МИНИСТЕРСТВО ОБРАЗОВАНИЯ И НАУКИ РОССИЙСКОЙ ФЕДЕРАЦИИ НАЦИОНАЛЬНЫЙ ИССЛЕДОВАТЕЛЬСКИЙ ЯДЕРНЫЙ УНИВЕРСИТЕТ «МИФИ» ОБНИНСКИЙ ИНСТИТУТ АТОМНОЙ ЭНЕРГЕТИКИ Е.А. АВРАМОВА NUCLEAR ENGLISH FOR UNIVERSITY STUDENTS Учебное пособие по английскому языку Рекомендовано УМО «Ядерные физика и технологии» в качестве учебного пособия для студентов высших учебных заведений Москва 2013 УДК 811.111(075.8) ББК 81.2Англя7 А21 Аврамова Е.А. Nuclear English for University Students: Учебное пособие по английскому языку. М.: НИЯУ МИФИ, 2013. – 88 с. Составлено в соответствии с Государственным образовательным стандартом по дисциплине «Иностранный язык». Цель пособия – формирование у студентов ядерно-энергетических специальностей навыков профессиональной коммуникации на английском языке. Пособие содержит тщательно отобранные оригинальные современные тексты по ядерным технологиям. К ним разработана система упражнений, нацеленных на овладение общенаучной лексикой, а также терминологией, относящейся к профессиональной сфере деятельности студентов. Упражнения к текстам имеют коммуникативную направленность и позволяют вовлекать студентов во все виды речевой деятельности. Предназначено для студентов ядерно-энергетических специальностей, продолжающих изучение иностранного языка в вузе. Подготовлено в рамках Программы создания и развития НИЯУ МИФИ. Рецензент канд. пед. наук Ю.В. Фалькович ISBN 978-5-7262-1733-8 © Национальный исследовательский ядерный университет «МИФИ», 2013 Корректор М.А. Никитина Оригинал-макет подготовлен С.Б. Долговой Подписано в печать 15.11.2012. Формат 60×84 1/16 Уч.-изд. л. 5,5. Печ. л. 5,5. Тираж 510 экз. Изд. № 42/1. Заказ № 15. Национальный исследовательский ядерный университет «МИФИ». 115409, Москва, Каширское ш., 31 ООО «Полиграфический комплекс «Курчатовский». 144000, Московская обл., г. Электросталь, ул. Красная, д. 42 INTRODUCTION Indeed, perchance, electrons may be Worlds themselves, with continents five, With memories, full forty ages Of science, art, of war or life. And may be, too, our every atom Has stars and planets by the score, Compressing into unique pattern All that we are owners of, and more. Быть может, эти электроны Миры, где пять материков, Искусства, знанья, войны, троны И память сорока веков! Еще, быть может, каждый атом Вселенная, где сто планет, Там – все, что здесь в объеме сжатом, Но также то, чего здесь нет. This poem “The World of the Electron” was written by the famous Russian poet Valery Bryusov in 1922. When he wrote it, he was inspired by the revolutionary scientific discoveries made by J. J. Thomson, Ernest Rutherford, Niels Bohr and others at the beginning of the 20th century. Until the end of the 19th century the atom was thought to be nothing more than a tiny indivisible sphere. However, a series of discoveries in the fields of chemistry, electricity and magnetism, radioactivity, and quantum mechanics in the late 19th and early 20th centuries changed all 3 that. Thanks to these discoveries, scientists split the atom into smaller pieces called subatomic particles and harnessed the power of the atom. These discoveries changed the world and paved the way to controlled nuclear fission. As a result, scientists learned to make atomic bombs and generate electricity by nuclear power. But what exactly is an atom? What is it made of? What does it look like? UNIT I The Structure of the Atom What do you know about the atom? Before you go on, check yourself by doing the Atom Quiz. The Atom Quiz 1. Who was the first to devise the idea of the atom? A. Democritus B. John Dalton C. Werner Heisenberg 2. What cannot be broken down by chemical reactions? A. compound B. element C. molecule 3. What do the properties of an element depend on? A. the electron shell B. the number of fundamental particles C. the number and arrangement of fundamental particles 4. What does the word “isotope” mean? A. occupying the same place B. indivisible C. having the same number of protons 5. How do isotopes differ from each other? A. in chemical properties B. in nuclear properties C. in physical properties 6. What is the smallest piece of a compound that keeps its chemical properties? A. molecule 4 B. neutron C. electron 7. What is the nucleus of an atom composed of? A. protons and neutrons B. neutrons and electrons C. protons, neutrons and electrons 8. Who discovered the electron? A. J.J. Thomson B. Dmitry Mendeleyev C. Amadeo Avogadro 9. What is the atomic weight determined by? A. the number of neutrons B. the number of neutrons and protons C. the number of electrons 10. Who were X-rays discovered by? A. Becquerel B. Roentgen C. Rutherford 11. What is another name for the Rutherford nuclear atom model? A. the drop model B. the solar-system model C. the plum-pudding model 12. What atom was the Bohr model based on? A. oxygen atom B. nitrogen atom C. hydrogen atom Reading 1-A The Thomson Atom: Discovering the Electron Read the text and choose a suitable heading for each part. There is one extra heading. A Discovery of the electron B Origin and meaning of the word «atom» C The plum-pudding model D Invisible and indivisible E Two hypotheses 5 1. The idea of an atom came from ancient Greek science/philosophy. The English word “atom” comes from the Greek word “atomos” meaning the smallest unit of matter. The idea of an atom was first proposed in 530 B.C. by Democritus, who thought that atoms were invisible and indivisible. We know it is not so, but we continue to use the word to designate the smallest particle which takes part in chemical interactions. 2. Every atom is electrically neutral and consists at least in part of equal amounts of positive and negative charge. The negative charge carriers in an atom are called electrons. The mass of an electron is very small compared to the mass of even the smallest atom (hydrogen). So, the question arises as to how the rest of the mass of the atom is distributed. If it is distributed uniformly throughout the atom, then it should occupy а spherical volume whose radius is about 10-10 meters, which is the radius of any atom. But it is also possible that it is concentrated into a smaller volume inside the atom in a compact arrangement of mass and charge called a nucleus. 3. The notion that the positive charge in an atom is spread out uniformly in a sphere with a radius of 10-10 meters was advanced by the British physicist J. J. Thomson around 1900. In 1897, he was studying the relationship between electricity and matter. He carried out experiments with cathode rays. From his experiments Thomson concluded that cathode rays were made of tiny, negatively charged particles, which he called electrons. He believed that they came from inside the atoms. He also thought that because the electron was negatively charged and the atom was electrically neutral, there must be a positive charge somewhere in the atom. 4. From these results, Thomson proposed a model of the atom. In this model the positive charge carriers are uniformly distributed throughout the atom as a whole, and all the space in the atom is occupied by electrons and positive charge carriers. The Thomson model is often called the plum pudding model of the atom because the electrons which neutralize the positive charge are supposed to be sсаtterеd around in the positive charge mass like plums in a plum pudding. Exercise 1. Match the following Russian and English equivalents. 1. To designate a particle a) Модель сливового пудинга 2. Chemical interactions b) Возникает вопрос 3. Charge carriers c) Обозначать частицу 4. Equal amount of charge d) Предложить модель 5. The question arises e) Компактное расположение 6 6. To distribute uniformly 7. Spherical volume 8. Compact arrangement 9. To advance a notion 10. The plum-pudding model 11. To occupy space 12. To study the relationship 13. To propose a model 14. According to the theory f) Занимать пространство g) Носители заряда h) Изучать взаимосвязь i) Химические взаимодействия j) Сферический объем k) Одинаковое количество заряда l) Выдвигать концепцию m) Согласно теории n) Распределять равномерно Exercise 2. Complete the sentences with the words from Reading 1-A. 1. The atom is the smallest ______ which takes part in chemical ______. 2. The idea of an atom was first proposed by ______ in ______. 3. He thought that atoms were ______ and _______. 4. One of the early models of an atom was advanced by _______ at the end of the 19th century. 5. According to this model, the positive charge carriers are uniformly _________ throughout the atom. 6. _______ are like plums in a plum pudding. 7. That is why the model is called the ____ ____ model. Exercise 3. Give the derivatives of the words below. 1. To divide –деление, неделимый. 2. To act – взаимодействовать, взаимодействие. 3. To compare – сравнительный, по сравнению. 4. To arrange – расположение. 5. To relate to – отношение, относительный, относительность. 6. To conclude – вывод/заключение 7. To scatter– рассеяние. 8. To charge – заряженный, разрядить. 9. Sign – сигнал, конструировать, обозначать. 10. Chemistry – химический, химик. 11. Neutron – нейтральный, нейтрализовать. 12. Science – ученый, научный. 7 Exercise 4. Read the text again and answer the questions below. 1. Where does the word "atom" come from? What does it mean? 2. Who proposed the idea of an atom? 3. What is the modern meaning of the word “atom”? 4. What is the charge of the atom? What is its size? 5. How does the mass of the electron compare with that of the atom? 6. What two hypotheses were put forward to explain the distribution of positive and negative charge in an atom? 7. What is the structure of the atom according to J.J. Thomson? Time for Fun Enjoy the joke: Two atoms bump into each other. One says 'I think I lost an electron!' The other asks, 'Are you sure?' to which the first replies, 'I'm positive.' Reading 1-B The Rutherford Atom "Your theory is crazy...but it's not crazy enough to be true." (Niels Bohr) The counter hypothesis that the positive charge carriers in an atom are not uniformly distributed throughout the atom but are concentrated in а small region at its centre is called the nuclear atom theory. The nuclear atom is often referred to аs the Rutherford atom after Ernest Rutherford who headed the team which carried out the first аlpha-particle scattering experiments. The Rutherford atom соnsists of а highly concentrated mass with а positive charge callеd the nucleus surrounded by negative charge carriers called electrons. Almost all the mass of the atom resides in the nucleus, which is composed of two different types of stable particles of almost equal mass, the proton which is positively charged and the neutron which is electrically neutral. The mass of the electron is 1/1836-th that of the proton, and although its charge is opposite in sign, it is numerically equal to that оf the proton. The number of planetary electrons in the electrically neutral atom is therefore 8 equal to the number of protons in the nucleus. The chemical behavior of an atom is determined by its number of planetary electrons. Chemical combinations between atoms take place when combining atoms transfer or share outer electrons. The Rutherford atom has аlsо been called the solar-system atom, since the concentration of mass in a nucleus surrounded by electrons reminds us of the sun-planet system in which we live. Actually, the differences between the solar system and the nuclear atom are much more scientifically significant than their similarities are. For example, the force which holds the planets in their orbits is gravitational, while the force which holds electrons in their orbits is elесtriсаl. Exercise 1. Match the two parts of the sentences below. Look at Reading 1-B to help you. 1. The nuclear-atom model was advanced by... 2. According to this model, the positive charge carriers... 3. Electrons are like... 4. Hence, another name of this model is ... 5. Actually, there is a great difference between... 6. The force that holds the planets together is gravitational, while… A. ....are concentrated in the nucleus and the electrons are revolving around the nucleus. B. .... planets in the solar system. C. ....the force that holds the atom together is electrical. D. ....Ernest Rutherford at the beginning of the 20th century. E. ....the solar-system model of the atom. F. ….the nuclear atom and the solar system. Exercise 2. Find the following international words in Reading 1-A and Reading 1-B. Copy them out. Радиус, ядро, гипотеза, теория, модель, электрон, масса, орбита, положительный, нейтральный, электрический, стабильный, планетарный, солнечный, химический, гравитационный, концентрироваться, нейтрализовать. 9 Exercise 3. Use Reading 1-B to find the English equivalents for the following Russian phrases. Противоположная гипотеза, модель ядерного атома, солнечная система, проводить эксперименты, эксперименты по рассеянию альфа-частиц, состоять из, противоположный по знаку, численно равен, соединяться – химические связи, определять химическое поведение, передавать электроны, важное сходство. Exercise 4. Match the two parts to make expressions from Reading 1-B. Read the text again if necessary. 1. counter 2. chemical 3. alpha-particle 4. opposite 5. numerically 6. transfer 7. uniformly a) electrons b) equal c) distributed d) behavior e) hypothesis f) in sign g) scattering experiments Now complete these sentences using the expressions above. 1. The _____________ that the positive charge carriers in an atom are not _______________ throughout the atom but are concentrated in а small region at its centre is called the nuclear atom theory. 2. The nuclear atom is often referred to аs the Rutherford atom after Ernest Rutherford who headed the team which carried out the first _____________. 3. Although the charge of the electron is ________, it is _________ to that оf the proton. 4. The _________ of an atom is determined by its number of planetary electrons. 5. Chemical combinations between atoms take place when combining atoms ______ or share outer electrons. Exercise 5. Read the text again and answer the questions below. 1. Who was the nuclear atom model proposed by? 2. Where are the positive charge carriers concentrated according to Ernest Rutherford? 3. What is the nucleus surrounded by? 10 4. What is the nucleus composed of? 5. What is the chemical behavior of an atom determined by? 6. In what way do chemical combinations take place between atoms? 7. Why is the nuclear-atom model sometimes called the solar-system model of the atom? 8. What is the difference between the nuclear atom and the solar system? Exercise 6. Do you know how the nucleus was discovered? Read the passage below and find out. Think of suitable headings for paragraphs 1-4. Rutherford’s Alpha-Particle Scattering Experiments 1. At about the same time as Thomson conducted experiments with cathode rays, physicists such as Henri Becquerel, Marie Curie, Pierre Curie, and Ernest Rutherford were studying radioactivity. 2. The experiment with radioactivity that contributed most to our knowledge of the structure of the atom was made by Rutherford and his colleagues. Rutherford bombarded a thin foil of gold with a beam of alpha particles and observed the beams on a fluorescent screen. 3. He noticed the following: most of the particles went straight through the foil and struck the screen. Some (0.1 percent) were deflected or scattered (at various angles) in front of the foil, while others were scattered behind the foil. However, a few particles were deflected sharply, by 90 degrees. 11 4. Therefore, Rutherford concluded that the gold atoms were mostly empty space, which allowed most of the alpha particles to pass through. However, some small region of the atom must have been dense enough to deflect or scatter the alpha particle. He called this dense region the nucleus; the nucleus contained most of the mass of the atom. Exercise 7. Put each of the following words in its correct place in the passage below. Think of a suitable heading for the passage. Close the book and write the passage in your own words. Particle, nucleus, neutron, electron, uncharged, radiation, proton, subatomic, weight, number. When Rutherford bombarded nitrogen with alpha particles, a positively charged particle that was lighter than the alpha particle was emitand realized that it was a fundated. He called this particle a (a) . The proton has a mass about 1,836 mental particle in the (b) times larger than the (c) ! However, the proton could not be the only (d) in the nucleus because the (e) of protons in any given element was less than the (f) of the nucleus. Therefore, a third, neutrally charged particle must exist! It was James Chadwick, a British physicist and co-worker of Ruther. Chadwick ford, who discovered the third (g) _____ particle, the (h) bombarded beryllium foil with alpha particles and noticed very high-energy (i) coming out. Chadwick concluded that this radiation was a stream of (j) _____ particles with about the same mass as the proton. Time for Fun Enjoy the joke: A neutron walks into a bar. "I'd like a beer" he says. The bartender promptly serves up a beer. "How much will that be?" asks the neutron. “For you?" replies the bartender, "no charge." Reading 1-C Quantum Mechanics Throws Light on the Atom: The Bohr Model Before reading the passage refer to the list of terms in Exercise 1. They will help you understand the text. Q: What happens when electrons lose their energy? A: They get Bohr'ed. 12 The Rutherford model of the atom presented a problem. If Rutherford was right and the electrons moved in a circle, they would lose energy, slow down and fall into the nucleus. In fact, it was calculated that the Rutherford atom would last only a few billionths of a second before collapsing! Something was missing! In 1913, the Danish physicist named Niels Bohr noticed the problem with Rutherford’s idea. He modified Rutherford’s model by proposing that electrons had set energy levels. One method of observing indirectly what is going on inside the atom is tо analyze the spectra produced when samples of various elementary substances are made to glow. Bohr studied the spectra emitted by hydrogen. He chose hydrogen because the hydrogen atom has the smallest mass and nuclear charge and it is the least complicated structurally. Bohr discovered that the visible spectrum of hydrogen is bright line. However, according to the classical theory of electromagnetic waves, atoms should emit radiation over а continuous spectrum. This prediction is not consistent with the bright-line spectra characteristic of hydrogen. So, the classical theory of electromagnetic waves could not explain the observed bright-line spectrum of hydrogen. To account for the fact that the hydrogen atom does not emit electromagnetic waves continuously, Niels Bohr put forward the theory based on three postulates: 1. The electron in а hydrogen atom exists only in certain allowable orbits (оr shells) and while it is in any of these orbits the electron does not radiate energy. 2. These orbits are such that the angular momentum of the electron about the nucleus is an integral multiple of h/2, where h is Plank's constant (the universal constant relating the frequency of radiation, F, to its quantum of energy, Е). 3. Emission оr absorption of radiation occurs when an electron jumps from one of the so-called stationary states of energy, E1, to another state of energy, Е2. In other words, Bohr suggested that electrons move in circular orbits with set energy levels around the atomic nucleus. Only certain orbits are allowed, and in these allowable orbits, the electrons do not radiate energy. 13 The atom emits electromagnetic radiation (a photon), when its electron changes from an orbit with a higher energy to an orbit with a lower energy. The transition from one energy level to another is sometimes called the “quantum jump” indicating that this process is not continuous. Despite the new questions this model raised (e.g. how orbiting electrons avoid violating the rules of electricity and magnetism when they do not fall into the nucleus), this model was powerful and led to a number of new discoveries: from predicting the outcome of chemical reactions, to determining the composition of distant stars, to developing the atomic bomb. Exercise 1. Learn the terms below. 1. Set energy levels 2. Samples of various substances 3. Allowable orbits (shells) 4. Bright-line spectrum 5. Continuous spectrum 6. An integral multiple 7. Angular momentum 8. Quantum jump 9. To violate the rule 10. Outcome of a reaction a) Постоянные уровни энергии b) Образцы различных веществ c) Допустимые орбиты d) Линейчатый спектр e) Сплошной спектр f) Целое кратное g) Угловой момент h) Квантовый скачок i) Нарушать правило/закон j) Результат реакции Exercise 2. Read the text again and put these statements in the correct order. The first one is done for you: 1 – B. A. To account for this difference, Bohr put forward three postulates. B. Bohr analyzed the spectra emitted by the hydrogen atom to study the atom structure. C. Bohr’s model is quite a good approximation to other atoms. D. He chose the hydrogen atom, because it is the least complicated structurally and has the smallest mass and nuclear charge. E. According to Bohr, the atom emits electromagnetic radiation (a photon), when its electron changes from an orbit with a higher energy to an orbit with a lower energy. F. Bohr’s observation was not consistent with the classical theory, because the classical theory says that the atom should emit radiation continuously. 14 G. He observed that the spectrum emitted by the hydrogen atom was not continuous. H. This transition from one energy state to another is called the “quantum jump”. Exercise 3. Use Reading 1-C to find the English equivalents for the following Russian phrases. Представлять проблему; замедлять электрон; существовать несколько миллиардных долей секунды; предложить; объяснять; видимый спектр; согласно классической теории; это предсказание не согласуется с; спектры, характерные для водорода; выдвинуть теорию; допустимые орбиты; квантовый скачок; частота излучения; поднимать/вызвать новые вопросы; нарушать правило/закон; предсказать результат реакции; определить состав; создать атомную бомбу; несмотря на; фактически; однако; другими словами. Exercise 4. Read the text again and answer the questions below. 1. What was the problem with the Rutherford model of the atom? 2. What method did Bohr use to study the atom structure? 3. Why did he choose the hydrogen atom? 4. What spectrum did hydrogen atom produce? 5. Why was his observation not consistent with the classical theory? 6. What postulates did Bohr put forward to account for this difference? 7. Does the Bohr model apply to the hydrogen atom only? Exercise 5. 1) Speak about the structure of the atom and its fundamental particles. 2) Compare the Thomson and the Rutherford models of the atom. 3) Describe the Bohr model of the atom. Use the following expressions: 1. The question arises… 2. …according to the hypothesis… 3. …is referred to as… 4. It was found that… It can be shown that… It is possible that… 5. In fact, actually, as a matter of fact 6. The theory is consistent with… 15 Enjoy the poem: The well-known rhyme "This is the House that Jack Built" was parodied on the occasion оf Niels Bohr's birthday. Enjoy the poem below. The Atom that Bohr Built (With apologies to 'Jack' from Bohr's colleague, Professor Rudolph E. Peierls) This is the atom that Bohr built. This is the nucleus That sits in the atom That Bohr built. This is the drop that looks like the nucleus That sits in the atom That Bohr built. These are the compound levels galore That make up the spectrum That's due to the modes That belong to the drop That looks like the nucleus That sits in the atom That Bohr built. This is the shell and this is the core That possesses the compound levels galore That make up the spectrum That's due to the modes That belong to the drop That looks like the nucleus That sits in the atom That Bohr built. This is correspondence (as Bohr said before) That holds in the shell as well as the core That possesses the compound levels galore That make up the spectrum That's due to the modes That belong to the drop That looks like the nucleus That sits in the atom That Bohr built. 16 This is the day we celebrate Bohr Who gave us the complementarity law That gives correspondence (as Bohr said before) That holds in the shell as well as the core That possesses the compound levels galore That make up the spectrum That's due to the modes That belong to the drop That looks like the nucleus That sits in the atom That Bohr built. The poem was translated into Russian by the Soviet and American scientist Valentin Turchin, a co-author of the book Physicists Continue to Laugh («Физики продолжают шутить»). Атом, который построил Бор Вот атом, который построил Бор. Это – протон, Который в центр помещен Атома, который построил Бор. А вот электрон, Который стремглав облетает протон, Который в центре помещен Атома, который построил Бор. Вот мю-мезон, Который распался на электрон, Который стремглав облетает протон, Который в центре помещен Атома, который построил Бор. А вот пи-мезон, Который распавшись дал мю-мезон, Который распался на электрон, Который стремглав облетает протон, Который в центре помещен Атома, который построил Бор. 17 А вот дополнительность. Это закон, Который Бором провозглашен. Закон всех народов, Закон всех времен, Успешно описывающий с двух сторон Не только протон И электрон, Но также нейтрон, Фотон, Позитрон, Фонон, Магнон, Экситон, Полярон, Бетатрон, Синхротрон, Фазотрон, Циклотрон, Циклон, Цейлон, Нейлон, Перлон, Одеколон, Декамерон, И, несомненно, каждый нейрон Мозга, которым изобретен Тот замечательный беватрон, В котором ускорился тот протон, Который в ударе родил пи-мезон, Который распавшись дал мю-мезон, Который распался на электрон, Который стремглав облетает протон, Который в центре помещен Атома, который построил Нильс Бор! 18 UNIT 2 Reading 2-А Quark Hypothesis 1. The word "atom" means “indivisible”, and it was once thought that аtoms were the ultimate, indivisible constituents of matter, that is, they were regarded аs elementary particles. One of the principal achievements of physics in the 20th century was the revelation that the atom is not indivisible or elementary, but has а complex structure. In 1911 Ernest Rutherford showed that the atom consists of а small, dense nucleus surrounded by a cloud of electrons. It was later revealed that the nucleus itself can be broken down into discrete particles, the protons and neutrons, and since then а great many related particles have been identified. During the past few decades it has become apparent that those particles, too, are complex rather than elementary. 2. They are now thought to be made up of simpler things called quarks. А solitary (одиночный) quark has never been observed, in spite of many attempts to isolate one. Nonetheless, there are excellent grounds for believing they do exist. More important, quarks seem to be truly elementary. 3. Subatomic particles can be classified into large families according to the kinds of interactions they participate in, or according to the kinds of forces they "feel." These forces are: gravitation, electromagnetism, the strong force and the weak force. All particles except the photon are classified according to their response to the last two forces. Those that feel the strong force are called hadrons (from the Greek word meaning "large'"); 19 those that do not feel the strong force but do respond to the weak force are called leptons. There are just six of them: the electron and the electron neutrino, the muon and the muon neutrino, the tau lepton and the tau neutrino (and their six antiparticles). The leptons give every indication of being elementary particles. The electron, for example, behaves as а point charge, and even when it is studied at the energies of the largest particle accelerators, no internal structure саn be detected. 4. The hadrons, on the other hand, seem complex. They have а measurable size of about 10-13 centimeters. Moreover, there are hundreds of them, and most of them are massive and unstable. It was in an effort to explain this great variety of particles that the quark hypothesis appeared. It was introduced independently in 1963 by Murray Gell-Mann and by George Zweig, both of the California Institute of Technology. Murray Gell-Man (left) and George Zweig (right) 5. The quark model states that a quark is an elementary particle and a fundamental constituent of matter. Quarks combine to form particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Quarks are never found in isolation; they can only be found within hadrons. When the quark hypothesis was first proposed, there were supposed to be three kinds of quark. The revised version of the theory requires 18 kinds (and 18 anti-quarks). In the terminology that has evolved for the discussion of quarks they are said to come in six flavors, and each flavor is said to come in three colors. ("Flavor" and "color" are, of course, arbitrary labels; they have no relation to the usual meanings of those words). 20 Exercise 1. The following five sentences (A-F) summarize the five paragraphs of Reading 2-A. Read the sentences and then match them to the paragraphs of Reading 2-A, 1-5. A. Subatomic particles can be classified into hadrons and leptons. B. Hadrons are made up of quarks which come in six flavors and three colors. C. Quarks are truly elementary. D. The atomic nucleus consists of particles which are complex rather than elementary. E. The quark hypothesis was proposed to explain the hundreds of particles known at the time as different combinations of quarks. Exercise 2. Use Reading 2-A to find the English equivalents for the following Russian phrases. Конечные составляющие; рассматривать; впоследствии было обнаружено; определять (распознавать) частицы; сложные, а не элементарные; есть основания полагать; выделить кварки; реакция на силу; обнаружить внутреннее строение; вводить гипотезу; предлагать; предполагать; «аромат» и «цвет»; произвольные названия (ярлыки); не иметь отношения к; обычное значение слова; за исключением фотона; несмотря на попытки; тем не менее; более того; то есть; согласно. Exercise 3. Below you will see a list of words related to Reading 2-A. Translate the words and write ten sentences using the words below. 1. 2. 3. 4. 5. Verb To constitute To achieve To reveal To relate (to) 6. To identify 7. To observe 8. To exist Noun a constituent achievement revelation density relation relative relativity identification identity observer observation existence 21 Adjective constituent dense related relative identical observable existing 9. To respond (to) 10. To behave 11. To detect 12. To introduce 13. To require response responsibility behaviour detection detector detective introduction requirement responsible introductory requiring Exercise 4. Complete the following sentences using the words and phrases from Reading 2-A. 1. One of the principal achievements of the 20th century was… 2. In 1911 Ernest Rutherford showed that… 3. During the past few decades it has become apparent… 4. Those particles are now thought to be made up of… 5. Quarks seem to be… 6. Subatomic particles can be classified according to… 7. Those that feel the strong force are referred to as… 8. Those that respond to the weak force are referred to as… 9. Leptons give every indication of… 10. There are just six of them: … 11. Hadrons, on the other hand, seem complex, and there are… 12. It was in an effort to explain this great variety of particles… 13. The quark hypothesis was introduced … 14. The quark model states that… 15. The revised version requires… 16. “Flavor” and “color” have no relation to…. Exercise 5. Read the text again and answer the questions below. 1. Who was the first to show that the atom consists of a small dense nucleus surrounded by electrons? 2. What other particles have been identified since Rutherford’s discovery in 1911? 3. Are these particles really elementary? What are they made up of? 4. Into what two families can subatomic particles be divided? 5. According to what principle can they be classified? 6. In general, how many forces are there? 7. What force do hadrons feel? 22 8. What force do leptons respond to? 9. How many leptons are there? 10. Why are leptons regarded as truly elementary particles? 11. Why did the quark hypothesis appear? 12. Who was it introduced by and when? 13. What does the quark hypothesis state? 14. How many kinds of quarks does the revised version of the hypothesis require? Do you know how the quark got its name? In 1963, Murray Gell-Mann and George Zweig suggested that hundreds of the particles known at the time could be explained as combinations of just three fundamental particles. Gell-Mann chose the name "quarks," pronounced "kworks," for these three particles, a nonsense word used by James Joyce in the novel Finnegan's Wake (Джеймс Джойс «Поминки по Финнегану»): "Three quarks for Muster Mark!" Reading 2-B Classification of Quarks Read the passage below and write it down in your own words. There are six different types of quarks known as flavors with three "color charges" each. There are the up, the down, the charm, the strange, the top, and the bottom quarks, each with a "red" charge, a "blue" charge, or a "green" charge. For every quark flavor there is a corresponding type of antiparticle, known as anti-quark that differs from the 23 quark only in sign. There are six anti-quarks, each with "anti-color charges." The anti-colors are anti-green, anti-red, and anti-blue. So, there are in all 36 quarks. Quarks have various properties, including electric charge, color charge, spin, and mass. Quarks are the only elementary particles which feel all four fundamental interactions, also known as fundamental forces (electromagnetism, gravitation, strong interaction, and weak interaction). Reading 2-C You are going to read a passage about neutrinos. Five sentences have been removed from the text. Choose from the sentences A-F the one which fits each gap (1-5). There is one extra sentence which you will not need to use. A. But for a long time it was not known whether the neutrino had mass. B. This discovery was of tremendous scientific importance because it radically changed our concept of the Universe. C. Nobody doubted it any longer. D. A solitary quark has never been observed. E. One of them is the neutrino's fantastic penetrating capacity. F. This makes the neutrino extremely difficult to detect. 24 The Mysterious Neutrino The elementary particle called the neutrino from the Italian "little neutral one" was predicted in 1931 by the Swiss scientist Wolfgang Pauli. For а long time it remained just a hypothesis, and it was not before 1956 that American physicists С. Cowan and F.Reines made the first experiment in which а neutrino beam produced an observable effect. 1).____________. Further studies revealed some very important properties of this particle. 2).____________. Neutrino beams fly through planets and stars without interacting with their matter. The reason is that the neutrino is electrically neutral. In fact, the neutrino is a lepton which has no electrical charge. It travels close to the speed of light, and is able to pass through ordinary matter almost unaffected. 3).____________. It was established that neutrinos are created as a result of certain types of radioactive decay or nuclear reactions such as those that take place in the Sun, in nuclear reactors, or when cosmic rays hit atoms. 4).__________. In 1980 scientists at the Institute of Theoretical and Experimental Physics in Moscow managed to calculate the rest mass оf the electron neutrino - one of the three types of neutrino. The neutrino rest mass, which is approximately 35 electron volts (10,000 times less than the mass of the electron), was determined on the basis of analyzing the energy spectrum of electrons resulting from the radioactive decay of tritium. 5).____________. Reading 2-D Nanotechnology You are going to read five paragraphs about nanotechnology. Choose the most suitable heading from the list A-F for each part (1-5). There is one extra heading which you do not need to use. A. Graphite Versus Diamonds B. Apocalyptic Scenarios C. It’s a Small World D. Products with Nanotechnology E. Nanowires and Nanotubes F. How New is Nanotechnology? 25 1. In 1959, the famous physicist and future Nobel Prize winner Richard Feynman gave a lecture to the American Physical Society called "There's Plenty of Room at the Bottom" («Там внизу много места»). His speech was about the field of miniaturization and how he believed man would create increasingly smaller, powerful devices. In 1986, Eric Drexler wrote "Engines of Creation" («Машины созидания») and introduced the term nanotechnology. 2. At the nanoscale, objects are so small that we cannot see them -even with a light microscope. Nanoscientists have to use tools like scanning tunneling microscopes or atomic force microscopes to observe anything at the nanoscale. Scanning tunneling microscopes use a weak electric current to study the scanned material. Atomic force microscopes scan surfaces with an incredibly fine tip. Both microscopes send data to a computer, which can collect the information and display it graphically on a monitor. 3. What is the difference between graphite and diamonds? Both materials are made of carbon, but both have very different properties. Graphite is soft; diamonds are hard. Graphite conducts electricity, but diamonds are insulators and cannot conduct electricity. Graphite absorbs light; diamonds are usually transparent. Graphite and diamonds have these properties because of their differences at the nanoscale. They have different crystal structures: the way the carbon atoms are arranged in space is different for carbon and diamonds. 4. Eric Drexler, the man who introduced the word nanotechnology, presented a frightening end-of-the-world picture -- self-replicating (самовоспроизводящиеся) nanorobots getting out of control and rapidly consuming all matter on Earth as they use carbon from the environment to build more of themselves. It is called the "grey goo" («серая слизь») scenario, in which synthetic nano-size devices replace all organic material. According to another scenario, nanodevices made of organic material wipe out the Earth -- the "green goo" scenario. 5. You may be surprised to find out how many products on the market are already based on nanotechnology: sunscreens, self-cleaning glass, clothing, scratch-resistant coatings, antimicrobial bandages, 26 swimming-pool cleaners and disinfectants. New products incorporating nanotechnology are coming out every day. Wrinkle-resistant fabrics, deep-penetrating cosmetics, liquid crystal displays (LCD) and other goods using nanotechnology are on the market. Very soon, we'll see dozens of other nanotechnology products ranging from Intel microprocessors to bio-nanobatteries only a few nanometers thick. UNIT 3 Reading 3-А Radiation and Radioactivity "Life on earth has developed with an ever present background of radiation. It is not something new, invented by the wit of man: radiation has always been there." Eric J. Hall 1. As is the case with so many discoveries, the discovery of the phenomenon of radioactivity was purely accidental. It was discovered in 1896 by the French physicist Henri Becquerel (1852-1908), who was interested at that time in the phenomenon of fluorescence. Не found that compounds of uranium emitted rays that gave an impression on а photographic plate covered with black paper. These rays were able to pass through thin sheets of metal and other substances that are opaque to light. Becquerel called these rays 'radiation'. 2. It is now known that radiation is emitted by the atoms themselves. The radiation may be in the form of particles, such as neutrons, alpha particles, and beta particles, or waves of energy, such as gamma and Xrays. The property of certain atoms to emit radiation is called radioactivity. Such atoms are called radioactive, and the process in which they spontaneously disintegrate or decay emitting both particles and energy is known as radioactive decay. This process occurs because unstable isotopes tend to transform into different, more stable atoms. 3. As unstable isotopes decay and stabilize themselves in this way, a radioactive material becomes less radioactive. Atoms in a radioactive substance decay at a characteristic rate. Each radioactive substance has its own 'half-life'. The half-life is the time taken for half of the atoms of a radioactive substance to decay. Half-lives can range from a millionth of a second to millions of years depending on the element concerned. After one half-life 27 the level of radioactivity of a substance is halved, after two half-lives it is reduced to one quarter, after three half-lives to one-eighth, and so on. Take iodine-131, which has a half-life of eight days. If we start off with a billion atoms of I-131, it will be practically all gone within three months. On the other hand, uranium-238 has a half-life of about 4.6 billion years, which is about the lifetime of the earth. Starting with a billion atoms of uranium, it takes 4. 6 billion years for half of them to become stable. 4. This leads to a very important fact about radioactivity. If a substance has a long half-life, it will not give off much radiation in a second - it will have 'low activity’. In general, substances with very long half-lives are not very radioactive. On the other hand, substances with very short half-lives are very radioactive but are soon gone. The most dangerous ones are those in between, such as caesium (half-life 28 years), which are radioactive enough to cause a problem, but have a long enough half-life to remain radioactive for a considerable period of time. Exercise 1. The following sentences (A-F) summarize the four paragraphs of Reading 3-A. Read the sentences and then match them to the paragraphs of Reading 3-A, 1-4. A. The radioactivity of a substance depends on its half-life. B. Radiation and radioactivity are not the same thing. C. The discovery of radioactivity was purely accidental. D. Each radioactive isotope has its own characteristic half-life which can range from a millionth of a second to millions of years. Exercise 2. Match the two parts of the sentences. Look at Reading 3-A to help you. 1. The property of certain atoms to emit radiation... 2. The radiation may be in the form of particles,... 3. The process in which radioactive atoms spontaneously disintegrate or decay... 4. This process occurs because unstable isotopes... 5. The half-life is the time... 6. Substances with very long half-lives are not very radioactive, … A. .... emitting both particles and energy is known as radioactive decay. B. .... tend to transform into different, more stable atoms. C. .... taken for half of the atoms of a radioactive substance to decay. 28 D. .... while substances with very short half-lives are very radioactive but are soon gone. E. .... such as neutrons, alpha particles, and beta particles, or waves of energy, such as gamma and X-rays. F. ….is called radioactivity. Exercise 3. Classify the nouns below according to their suffixes. Copy them out. Radiation, measurement, fluorescence, emission, impression, ability, passage, property, disintegration, stability, equipment, difference, excitation, tendency, dependence, density, voltage, requirement, existence, brevity, absorption, achievement, deflection, invention, isolation, substance, radioactivity, storage, development, accuracy. Exercise 4. Use Reading 3-A to find the English equivalents for the following Russian phrases. Как часто бывает с открытиями; интересоваться явлением; элементы и соединения; соединения урана; оставлять отпечаток на; проходить сквозь тонкие листы; непроницаемый для света; энергия в виде волн; радиоактивный распад; распадаться с характерной скоростью; находиться в диапазоне от… до…; данный элемент; вызывать проблему; оставаться радиоактивным; значительный период времени. Exercise 5. Read the text again and answer the questions below. 1. When was the phenomenon of radioactivity discovered? Who made this discovery? 2. How was the discovery made? 3. Where does radiation come from? 4. In what form can radiation be emitted? 5. What is radioactivity? What is the difference between radiation and radioactivity? 6. What is meant by radioactive decay? 7. Why does the process of radioactive decay occur? 8. What happens when unstable isotopes decay? 9. What is meant by the half-life of a radioactive substance? 10. What does the half-life of a radioactive substance depend on? 29 11. Which is more radioactive: substances with very long half-lives or those with very short half-lives? 12. What radioactive substances are the most dangerous ones? Reading 3-B Alpha, Beta and Gamma Rays Three different types оf radiation are emitted by radioactive substances. These radiations for brevity are called alpha rays, beta rays, and gamma rays. The alpha rays consist of positively charged particles projected from the parent atom with а velocity about one-tenth the velocity оf light. They are very easily absorbed by thin foil or by a few centimeters of air. They affect а photographic plate, cause many bodies to fluoresce brilliantly, and ionize the air through which they pass. They are deflected by an electric or a magnetic field. The beta rays consist of negatively charged particles which are projected from the atom of the radioactive substance with a velocity which is nearly, but not quite, as great as the velocity of light. Because of their larger velocities and smaller mass, they are much more penetrating than the alpha particles. They produce much less ionization in the gas through which they pass than do the alpha particles and are less active photographically than alpha particles. In an electric and magnetic field they are deflected just as cathode rays are deflected. The gamma rays are extremely penetrating, and are not deflected by either а magnetic or an electric field. Their nature is entirely different from that of the alpha or beta rays. They are electromagnetic pulses like very penetrating Х-rays. Exercise 1. Use Reading 3-B to find the English equivalents for the following Russian phrases. Поглощать излучение; воздействовать на фотопластинку; исходный атом; вызывать свечение; отклоняться в магнитном поле; из-за высокой скорости; проникающее излучение; ионизировать газ; вызывать ионизацию; электромагнитные импульсы; для краткости. 30 Exercise 2. Use the notes given below to write a description of three types of rays. Alpha-rays positively charged particles the velocity about 1/10 that of light to be absorbed by thin foil to affect a photographic plate to cause bodies to fluoresce to ionize the air to be deflected by an electric and magnetic field Beta-rays negatively charged particles the velocity is not as great as that of light much more penetrating to be less active photographically to produce less ionization to be deflected in an electric or magnetic field Gamma-rays electromagnetic pulses extremely penetrating to be unaffected by electric or magnetic fields Reading 3-C The Discovery of Radioactivity The existence of penetrating radiation that could pass through layers of opaque materials as if they were made of clear glass was а recognized fact at the time of Becquerel's discovery. In fact, only а year earlier (1895) а German physicist Wilhelm Roentgen (1845-1923), discovered X-rays, which can penetrate equally well through cardboard, black paper, or the human body. But there was an important difference between the rays discovered by Becquerel and the X-rays. While special equipment was required to produce X-rays, the radiation discovered by Becquerel was flowing from the piece of uranium ore without any external excitation. It was Marie Curie who invented the term ‘radioactive’ to describe a substance that gave out these new rays all the time. The early studies of the newly discovered phenomenon which was called radioactivity showed that the emission of mysterious radiation was completely unaffected by physical or chemical conditions. 31 It was soon found that this property of emitting penetrating radiations was not confined to uranium and its compounds. Thorium and its compounds and minerals containing thorium have this same property. Such substances are said to be radioactive. Ву studying the radioactive mineral called pitchblende (урановая смолка) which contained uranium and thorium Pierre and Marie Curie found that this mineral contained substances which were much more radioactive than either uranium or thorium. The Curies finally isolated two new elements. Marie called the first one ‘polonium’ after Poland, where she was born. The second one was called ‘radium’ because it was highly radioactive. Exercise 1. Use Reading 3-C to find the English equivalents for the following Russian phrases. Существование проникающего излучения; признавать - признанный факт; требовать специального оборудования; без внешнего возбуждения; ограничиваться соединениями урана; не зависеть от физических и химических условий; обладать таким же свойством; выделить новый элемент; как уран, так и торий; либо уран, либо торий; ни уран, ни торий. Exercise 2. Summary writing. Answer the questions below and write down your answers. You will get thirteen simple sentences. 1. Was penetrating radiation quite a new phenomenon at the time of Becquerel or was it a recognized fact? 2. Were X-rays discovered by Roentgen a year earlier? 3. Can X-rays discovered by Roentgen penetrate through opaque substances easily? 4. Is there a difference between X-rays and the rays discovered by Becquerel? 5. Do X-rays require special equipment? 6. Do Becquerel’s rays flow spontaneously from a piece of uranium ore? 7. Was the emission of mysterious radiation completely unaffected by physical or chemical conditions? 8. Is the spontaneous radiation confined to uranium compounds? 9. Do thorium compounds have the same property? 10. Did the Curies study pitchblende? 11. Is pitchblende a mixture of uranium and thorium? 12. Did they isolate new highly radioactive substances? 13. Did they call them polonium and radium? 32 Combine the sentences to make five complex sentences and write them as a paragraph. You can join the simple sentences in the following way: 1. Join 1 and 2 by means of «in fact». 2. Join 3 and 4 by «however». 3. Join 5 and 6 by «while». 4. Join 6 and 7 by «therefore», «thus» or «so». 5. Join 8 and 9 by «as». 6. Join 10 and 11 by «which». 7. Begin 12 with «As a result…» 8. Join 12 and 13 by «which». Do you know? Pitchblende is an old name for uraninite, which is uranium ore mineral, basically uranium oxide. Pitchblende is also the rock in which Marie Curie discovered radium. Pitchblende was first discovered in the silver mines of St. Joachimsthal (now the Czech Republic), as a material that accompanied rich silver deposits. «Pitchblende» comes from the German word «pechblende». The German word «blende» means «mineral», while «pech» means «bad luck», so it was literally the «bad-luck-mineral». Seeing this mineral was never welcome: it usually meant that there was no more silver left in the mine and that miners would have to work hard to start a new one. Pitchblende was useless at the time it was named. That was because nobody had a use for uranium at the time. The town of Joachimsthal is also known to have given its name to the U.S. dollar. In the 16th century, the silver mined there was used to produce coins, which were called «Joachimsthalers». The name was later shortened to «thalers» (талеры), and then changed into «dollars» in English-speaking countries. Isn't it ironic that a small town in the Czech Republic gave us the two things that shaped the modern world? Both have changed, and continue to affect our lives, our politics and international relations. 33 Reading 3-D How Dangerous is Radiation? Background radiation is that which is naturally and inevitably present in our environment. It is all around us, all the time. Our bodies are exposed to natural radiation every day -- from soil and underground gases to cosmic radiation from the sun and outer space. But radiation is not always dangerous. It depends on its strength, type and the length of exposure. Radiation comes in many forms and can be either ionizing or nonionizing. Ionizing radiation changes the physical state of atoms and causes them to become electrically charged or “ionized”. This means that when ionizing radiation passes through the body, it actually has enough energy to damage DNA and cause various diseases. Ionizing radiation is both natural and man-made. Some of the natural sources of ionizing radiation are naturally-occurring radionuclides in the earth, building materials, air, food and water, and cosmic rays. Medical and dental X-rays, smoke detectors and radionuclides emitted from nuclear power plants are good examples of man-made ionizing radiation. Overexposure to ionizing radiation can cause mutations in genes, which causes birth defects, a high risk of cancer, burns or radiation sickness. Non-ionizing radiation does not have enough energy to ionize atoms or molecules. It consists of electromagnetic radiation ranging from the extremely low frequency (ELF) to the ultraviolet (UV). Non-ionizing radiation sources include microwaves, radio waves, infrared radiation, visible light and lasers. We are constantly exposed to non-ionizing radiation from our own inventions – power lines, cell phones and microwave ovens. Although considered less dangerous than ionizing radiation, overexposure to non-ionizing radiation can cause health problems. Living things have evolved in an environment which has significant levels of ionizing radiation. Furthermore, many of us owe our lives and health to such radiation produced artificially. Ionizing radiation is used to diagnose diseases, and some people are treated with radiation to cure diseases. We all benefit from a great number of products and services made possible by the careful use of radiation. Exercise 1. Translate the following noun groups. Background radiation, uranium compounds, fluorescence phenomenon, reactor accident, mineral properties, metal sheets, radiation emission, 34 radiation exposure, energy waves, decay process, energy transformation, isotope disintegration, radioactivity level, isotope half-life, gas ionization. Exercise 2. What do the following abbreviations stand for? Refer to the dictionary or other sources if you do not know the answer. ELF, UV, DNA, REM, Bq, Ci, laser. Exercise 3. Give the derivatives of the words below. 1. Ground – фон. 2. Present – присутствие. 3. To expose to – воздействие, чрезмерное воздействие. 4. Danger – опасный. 5. Strong – интенсивность, сила. 6. Ion – ионизировать, ионизация, ионизирующий. 7. To vary – разнообразный, переменный. 8. Nature – естественный, естественно. 9. To detect – обнаружение, детектор. 10. Frequency – частый, часто. 11. To evolve – эволюция. 12. Sign – сигнал, значительный, конструировать. 13. Art – искусственный. 14. To benefit – полезный. Exercise 4. Use Readings 3-A, 3-B, 3-C and 3-D to find definitions for the terms below. Radioactivity, radiation, radioactive substances, radioactive decay, half-life, alpha-rays, beta-rays, gamma-rays, pitchblende, background radiation, ionizing radiation, non-ionizing radiation. Exercise 5. Discuss with your group one of the topics listed below. 1. Is background radiation dangerous? 2. Sources of natural and man-made background radiation. 3. Difference between ionizing and non-ionizing radiation. 4. Risks and benefits of ionizing radiation. 35 Reading 3-E Radiation Facts You are going to read five paragraphs about radiation. Choose the most suitable heading from the list A-F for each part (1-5). There is one extra heading which you do not need to use. A. Radium Girls B. X-Ray Shoe Fitter C. Living in a Radioactive World D. The Ironic Death of Marie Curie E. Your Superheroes Can Be Radioactive F. Radiation Can Be Good for You 1. We know today that overexposure to X-rays is dangerous. However, from the 1930s to the 1950s, salesmen in shoe shops actually used Xray machines for fitting shoes. It was estimated that there were 10,000 of these devices in use. The device consisted of an x-ray tube with a fluorescent (светящийся) screen above it. In use, the customer placed his or her feet between the two, and an X-ray image of the customer's feet with shoes on them appeared on the screen. In reality, the shoe-fitting machine was just a way to attract potential customers. In 1949, the dangers of radiation became widely known, and the machines disappeared from the shops during the 1950s. 2. Radiation exposure has always attracted comic book writers. We think it is because radiation can change DNA and cause mutations and superpowers. Here is just a short list of some comic book characters affected by radioactivity: Spider-Man, Radioactive Man, Godzilla, X-ray, Doctor Phosphorus. There are dozens more, and who knows how many are living in the minds of tomorrow's comic book writers? 3. Before you lock yourself down in your nuclear shelter, remember that some radiation is actually beneficial to your health. Ultraviolet (UV) radiation, for example, is necessary for the body to stimulate production of vitamin D. Yes, a little bit of sunlight is actually good for you. But experts say that five to 15 minutes a day, three times a week, is more than enough to keep your vitamin D levels high. 36 4. In the 1920s, a watch company used the newly discovered substance radium to make its watches glow in the dark. Thousands of girls went to work in the watch factory to paint watch dials with glow-in-thedark paint which contained radium. Thinking that the paint was harmless, the girls licked their paintbrushes to keep them sharp. For fun, the girls painted their teeth and lips and turned off the lights. Although managers regularly tested the girls for radioactivity, the women never received the results of these tests. Many of the workers became sick. Many others died over the years, but a link was never proved and the company never took responsibility. 5. Sadly, the very thing that made Marie Curie famous is what eventually killed her. In the late 1890s, both Marie and her husband Pierre began suffering from various diseases. Marie suffered several cataracts (a side effect of radiation) and eventually got leukaemia caused by exposure to large amounts of radiation from her research. After her death, Marie's family gave her lab journals to the Bibliotheque Nationale in Paris, where they are still kept. Some of these papers were so radioactive that they required years of decontamination before anyone could handle them. Nuclear Radiation Quiz This nuclear radiation quiz will test your knowledge of radiation and radioactivity facts. 1. What makes something radioactive? A. An unstable nucleus B. Elements with an atomic number higher than 83 C. Equal number of neutrons and protons in the atomic nucleus 2. Which of the following events would expose you to the most radiation? A. Living next to a nuclear power plant for a year B. Talking over your cell phone 15 minutes a day C. Getting an X-ray examination of your chest 3. How does radioactive material generate electricity? A. The heat generated during fission creates steam that powers electricity generating turbines. B. The decay of uranium creates enough force to turn turbines directly. C. To quote Joe Dirt, "How exactly does the sun set? It just does." 37 4. Which of the following typically poses the biggest health threat to humans? A. Alpha particles B. Beta particles C. Gamma rays 5. Which of the following household devices might contain radioactive material? A. Smoke detectors B. Thermometers C. Microwave ovens 6. How do you neutralize the radioactivity of a substance? A. Burn the material B. Pass a high-voltage current through the material C. It cannot be done. 7. Who was the first person to discover radioactivity? A. Ernest Rutherford B. Henri Becquerel C. Albert Einstein -- he pretty much discovered everything, right? 8. Who invented the term «radioactivity»? A. Marie Curie B. Pierre Curie C. Wilhelm Roentgen 9. What does the term "half-life" mean in reference to radioactive material? A. The amount of time it takes for a radioactive atom to decay B. The amount of time it takes for half of a given sample of a radioactive material to decay C. Half-life? That's one of my favorite computer games! 10. Which of the following IS NOT true? A. The radioactive element polonium was used as a minor component of a toy bicycle in the 1950s. B. Before the first nuclear bomb was detonated, scientists took bets on whether or not it would destroy the entire world. C. X-ray machines were once used in shoe stores to help the shoe fitting process before the dangers of radiation were well-known. 38 UNIT 4 Reading 4-А Nuclear Fission and Chain Reaction Q: What did the Nuclear Physicist have for lunch? A: Fission Chips. Nuclear fission is a nuclear reaction in which the nucleus of a heavy atom splits into lighter atoms, producing free neutrons and large amounts of energy. If it occurs without neutron bombardment, as a type of radioactive decay, this type of fission is called spontaneous fission. However, most nuclear fission occurs as a "nuclear reaction" (called induced fission) in a nuclear reactor as a result of the bombardment of heavy nuclei by neutrons. In nuclear reactions, a subatomic particle (a neutron) collides with an atomic nucleus and causes it to split. The splitting nucleus releases two or three new neutrons which cause more fissions in the neighbouring uranium atoms. This makes possible a selfsustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon. The isotopes that can sustain a fission chain reaction are called nuclear fuels, and are said to be fissile or fissionable. Uranium is the most common nuclear fuel. The two most important isotopes of uranium are uranium-238 and uranium-235. Uranium-238 (U-238) undergoes spontaneous fission very slowly and has an extremely long half-life (the time it takes for half of its atoms to decay) of 4.5 billion years. It goes through many stages of decay in its life span, eventually forming a stable isotope of lead. U-238 makes up 99 percent of the uranium on Earth, while uranium-235 (U-235) makes up about 0.7 percent of the remaining uranium found naturally. Uranium-235 is the most important of all the uranium isotopes. Like U-238, U-235 decays naturally, by emitting alpha radiation. However, U-235 is one of the few materials that can undergo induced fission. If a free neutron runs into a U-235 nucleus, the nucleus will absorb the neutron, become unstable and split immediately. The splitting of an atom releases tremendous heat. The decay of a single U-235 atom releases approximately 200 MeV (million electron volts). That may not seem like much, but there are a lot of uranium at39 oms in a pound (0.45 kg) of uranium. So many, in fact, that a pound of highly enriched uranium used to power a nuclear submarine is equal to about a million gallons of gasoline. The energy released by a single fission comes from the fact that the fission products and the neutrons, together, weigh less than the original U-235 atom. The difference in weight is converted directly to energy at a rate given by Einstein’s equation E = mc2. However, for all of this to work, uranium must be enriched so that it contains 3 to 5 percent U-235. Three-percent enrichment is sufficient for nuclear power plants, but weapons-grade uranium is composed of at least 90 percent U-235. Note: Fissionable materials can be either fissile or fertile. A fissile material is one that will undergo fission when bombarded by neutrons of any energy. The isotope uranium-235 is fissile. A fertile material is one that will capture a neutron, and transmute by radioactive decay into a fissile material. Uranium-238 is a fertile material. Fertile isotopes may also undergo fission directly, but only by fast, high-energy neutrons. Exercise 1. Match the two parts to make expressions from Reading 4-A. Read the text again if necessary. 1. spontaneous 2. undergo 3. half 4. self-sustaining 5. at a controlled 6. nuclear 7. weapons-grade a) induced fission b) chain reaction c) uranium d) weapon e) fission f) life g) rate Now complete these sentences using the expressions above. Uranium-238 (U-238) undergoes ______ very slowly and has an extremely long ______. 1. U-235 is one of the few materials that can ______. 2. A _______ releases energy______ in a nuclear reactor or at a very rapid uncontrolled rate in a _____. 3. Three-percent enrichment is sufficient for nuclear power plants, but _______ is composed of at least 90 percent U-235. 40 Exercise 2. Match the two parts of the sentences. Look at Reading 4-A to help you. 1. Nuclear fission is a nuclear reaction... 2. If it occurs without neutron bombardment, as a type of radioactive decay, ... 3. However, most nuclear fission occurs as induced fission in a nuclear reactor... 4. This makes possible a self-sustaining chain reaction... 5. The isotopes that can sustain a fission chain reaction... 6. Uranium 235 is one of the few materials … 7. The energy released by a single fission comes from the fact that the fission products and the neutrons … 8. The difference in weight is converted directly to energy … A. ... as a result of the bombardment of heavy nuclei by neutrons. B. … at a rate given by Einstein’s equation E = mc2. C. …weigh less than the original U-235 atom. D. ... in which the nucleus of a heavy atom splits into lighter atoms, producing free neutrons and large amounts of energy. E. ... that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon. F. ... are called nuclear fuels, and are said to be fissile or fissionable. G. ... this type of fission is called spontaneous fission. H. … that can undergo induced fission. Exercise 3. Use Reading 4-A to find the English equivalents for the following Russian phrases. Ядро – ядра – ядерная реакция; делиться на более легкие атомы, делящееся ядро, деление атома; радиоактивный распад; спонтанное деление, контролируемое деление; поддерживать цепную реакцию, самоподдерживающаяся цепная реакция; заставлять ядро делиться, вызвать дальнейшее деление; ядерное топливо, делящиеся материалы, подвергаться спонтанному делению (делиться спонтанно), период полураспада, природный уран, поглощать нейтрон, выделять огромное тепло, обогащать – обогащенный уран – обогащение, оружейный уран. Exercise 4. Give the derivatives of the words below. 1. To heat – тепло, отопление. 41 2. To weigh – вес. 3. To fission – деление, делящийся, способный к делению. 4. To collide – столкновение. 5. To bombard – бомбардировка. 6. To induce – индукция, индуцированный. 7. To cause – причина, потому что, из-за. 8. To absorb – поглощение. 9. To equal – равный, уравнение. 10. To remain – оставшаяся часть, остаток. 11. To convert – преобразование, преобразователь, обратимый. 12. To contain – содержание. 13. To compose – состав, разлагать. 14. To live – жизнь, период полураспада. 15. Possible – невозможный, возможность. Exercise 5. Use Reading 4-A to answer the questions below: 1. What is nuclear fission? 2. What is meant by spontaneous fission? Induced fission? 3. What causes the atom to split in a nuclear reaction of fission? 4. What makes the self-sustaining chain reaction possible? 5. In what two ways can the chain reaction release energy? 6. What is meant by fissile/fissionable materials? 7. What are the two most common uranium isotopes? 8. How does U-238 behave and what is it finally transformed into? 9. What is the proportion of U-238 to U-235 in nature? 10. Why is U-235 the most important of all the uranium isotopes? 11. How much energy does the splitting of a U-235 atom release? 12. Where does this energy come from? 13. What is required for the fission reaction to occur in a nuclear reactor? 14. What enrichment is required for a NPP? For weapons-grade uranium? Reading 4-B Emission of Neutrons Neutrons are ideal projectiles for nuclear bombardment because they have nо electrical charge and thus suffer no repulsion when they approach atomic nuclei. They are usually divided into thermal and fast neutrons according to their energy. 42 A thermal neutron is a neutron with a relatively low energy of less than 1 MeV, and a speed of 2.2 km/s. Fast neutrons are fast! A fast neutron is a neutron with a kinetic energy close to 2 MeV, and a speed of 28,000 km/s. Fast neutrons can be made into thermal neutrons using a process called moderation. This is done with a neutron moderator. Most fission reactors use a neutron moderator to slow down the fast neutrons so that they are more easily captured, causing further fission. In reactors, heavy water, light water, or graphite is used to moderate neutrons. The neutrons emitted as a result of the fission process can be divided into two categories, namely, prompt and delayed neutrons. The prompt neutrons are over 99 percent of the total fission neutrons. They are released within an extremely short interval of time, about 10-14 sec, of the fission process. Prompt neutrons are emitted directly by the fissioning nuclei. The delayed neutrons are produced by the decay of fission products and are emitted with a delay of a few seconds. The delayed neutrons are of great importance. They keep the chain reaction from developing into an uncontrolled process. Hence, they enable the reactor operation to be controlled. Exercise 1. Match the two parts to make expressions from Reading 4-B. Read the text again if necessary. 1. ideal 2. delayed 3. fission 4. neutron 5. uncontrolled 6. reactor 7. nuclear a) neutrons b) moderator c) process d) bombardment e) products f) projectiles g) operation Now complete these sentences using the expressions above. 1. Neutrons are _______ for ______ because they have nо electrical charge. 2. Most fission reactors use a ______ to slow down the fast neutrons so that they are more easily captured, causing further fission. 3. The _______ are produced by the decay of ______ and are emitted with a delay of a few seconds. 4. The delayed neutrons keep the chain reaction from developing into an _______. 43 Exercise 2. Use Reading 4-B to find the English equivalents for the following Russian phrases. Бомбардирующая частица, отталкивать – испытывать отталкивание, быстрые и тепловые нейтроны, замедление – замедлитель нейтронов, замедлять (быстрые) нейтроны, захватывать нейтроны, мгновенные и запаздывающие нейтроны, испускать/излучать нейтроны, продукты деления, распад, задержка в несколько секунд, управлять работой реактора. Exercise 3. Use Reading 4-B to answer the questions below. 1. Why are neutrons ideal projectiles for nuclear bombardment? 2. What is the difference between fast and thermal neutrons? 3. Into what two groups can fission neutrons be classified? 4. What is meant by “prompt” neutrons? 5. What is meant by “delayed” neutrons? 6. Why are delayed neutrons so important for fission reactors? Reading 4-C A Walk in the Snow You are going to read a passage about the discovery of fission. Five sentences have been removed from the text. Choose from the sentences A-F the one which fits each gap (1-5). There is one extra sentence which you will not need to use. A. Under the bombardment of neutrons, the uranium nuclei were splitting. B. It was Frisch who introduced the term “fission”. C. To his surprise, he only succeeded in producing isotopes of barium (Z=56). D. But Meitner never received the Nobel Prize for her work. E. He didn't know how the results of his research would be used. F. In Germany in 1938, Otto Hahn was studying the effect of irradiating heavy elements with neutrons. Who was the first to discover that heavy nuclei could undergo fission? 1).____________ He hoped the heavy nuclei would absorb the neutrons, creating “transuranic elements”. These have a higher atomic number than uranium, with more than 92 protons in their nuclei (expressed as Z=92). 2)._________ 44 Hahn wrote to one of his colleagues, Lise Meitner, to tell her about his curious finding. Meitner was a Jew and had to leave Nazi Germany to live in Sweden. During a walk in the snow with her nephew, the nuclear physicist Otto Frisch, she realized the importance of Hahn’s discovery. 3)._________ If barium (Z=56) was being produced, then so much krypton (Z=36), since 36+56=92. It soon became clear that this is not the only pair of nuclei that can be produced. Another possible pair is rubidium (Z=37) and caesium (Z=55). 4).________ And it was Meitner who suggested that it releases energy. A Nobel Prize was a suitable reward for the discovery of nuclear fission, and Hahn was awarded the chemistry prize for the work in 1944. 5)._________ It was a strange mistake that has provoked a lot of discussion among nuclear scientists. Reading 4-D Architect of the Nuclear Age Read the passage about the famous Italian physicist Enrico Fermi and answer the question: What role did Fermi play in the American atomic bomb project? Enrico Fermi discovered physics at the age of 14 and by 32 had developed the theory of beta decay. То explain it he had to introduce the fourth fundamental force of the universe, now known as Fermi’s ‘weak force’, the other three forces being gravity, electromagnetism and the strong force. In 1934, Fermi and his team conducted а series of experiments that involved bombarding atomic nuclei with neutrons, and obtained many new isotopes. As a by-product, they found that slowing down neutrons by passing them through paraffin increased their effectiveness. That was the most important discovery of his life, as it would allow the controlled release of nuclear energy in а reactor. For these two discoveries, Fermi was awarded the Nobel Prize in1938. In 1934 he had missed another Nobel Prize discovery - nuclear fission. The foil in which the uranium samples had been wrapped during experiments was too thick and the instruments were not sensitive enough to record the fission fragments. It was а blessing in disguise (something that at first appears to be bad or unlucky but is actually 45 good – «нет худа без добра»). If fission had been discovered then, Nazi Germany would have built an atomic bomb. In 1939 Fermi immigrated to the USA in order to save his Jewish wife Laura from anti-Semitic persecution in Mussolini’s Italy. Many Jewish scientists had to leave Nazi Germany for the same reason. Historians agree that if Hitler had not forced Jewish scientists to leave Europe, he might have got the atomic bomb before America. Fermi and other famous scientists who had left Europe, including Leo Szilard, John von Neumann, Edward Teller and Hans Bethe played an important role in the American nuclear story. In 1942, at the head of the multi-national research group, Fermi produced the first controlled, self-sustaining chain reaction. When in 1949 President Truman initiated the program to develop the hydrogen bomb, Fermi strongly opposed it. ‘It is clear that such а weapon cannot be justified on any ethical ground... The fact that no limits exist to the destructiveness of this weapon makes its very existence and the knowledge of its construction а danger to humanity as а whole,’ he wrote. His warnings were ignored. The Cold War arms race between America and the Soviet Union put the world at mortal risk. But there is no doubt that the discovery of controlled nuclear energy, in which Fermi’s role was so crucial, did have long-term beneficial results: a potentially unlimited source of energy and keeping humanity from another world-scale war. Exercise 1. Read the text again and answer the following questions. 1. What are Fermi's main contributions to nuclear physics? 2. Fermi and his group nearly made one more important discovery. What was it? Why did they fail? 3. What was Fermi's attitude to the hydrogen bomb program? Exercise 2. Suggest explanations for the following facts mentioned about Enrico Fermi in Reading 4-D. 1. He failed to discover nuclear fission. This fact is called «a blessing in disguise». 2. He was an Italian but lived and worked in the USA. 3. He played a crucial role in the development of the A-bomb but was against the H-bomb program. 46 Exercise 3. Match the following Russian and English equivalents. 1. To create a theory 2. To design a bomb 3. To increase the effectiveness 4. To play a crucial role 5. To put at mortal risk 6. To oppose strongly 7. To ignore the warnings 8. Cannot be justified a) Бета-распад b) Выделение ядерной энергии c) Создать теорию d) Неисчерпаемый источник энергии e) Гонка вооружений f) Не может быть оправдан(о) g) Играть важную роль h) Долгосрочные благоприятные результаты 9. Beta decay i) Война мирового масштаба 10. Arms race j) Подвергать смертельной опасности 11. Unlimited source of energy k) Выступать категорически против 12. World-scale war l) Повысить эффективность 13. Long-term beneficial results m) Не обращать внимания на предупреждения 14. Release of nuclear energy n) Создать (спроектировать) бомбу Exercise 4. Re-write the sentences and replace the underlined parts with the words or phrases listed below. Chain reaction, mortal danger, crucial, arms race, release, nuclear fission, beneficial, long-term effects 1. A competition between industrial countries to produce more and deadlier weapons is a waste of human and material resources which otherwise might be put to more beneficial uses. 2. Some specialists say that no matter how costly modern research may be the favorable and useful effects by far outweigh the costs. 3. Few specialists could predict the effects of the scientist's discoveries in the distant future. 4. The discovery of nuclear fission was of great importance for humankind in the 20th century. 5. On August 6, 1945, humankind became aware of the danger of complete destruction caused by nuclear weapons. 47 6. One free neutron can lead to the liberation of two or three; that makes the extraction of energy in useful quantities from the process of splitting the nucleus of certain atoms into parts possible. 7. The released neutrons can start a number of related changes in the fissile material, each of which causes the next, but it can also die out quickly if there is not enough U235, i.e., no critical mass of fissile material. Exercise 5. Read the last sentence in Reading 4-D again. Think about the questions below and write your answers to them. 1. According to the author, how did the developments in nuclear physics in the 20th century affect the humanity? 2. Do you agree with him? Why? Why not? Reading 4-E Nuclear Scientists and the Nuclear Bomb Look through these encyclopaedia entries about four scientists and say what they have in common. Why do you think these scientists took part in the nuclear projects? Hans Bethe – a German physicist who went to the USA to escape the Nazis in 1935, discovered the fusion reactions that power the stars, directed work on the first A-bombs and contributed to the H-bomb. At the same time he strongly opposed nuclear testing and the nuclear arms race. J. Robert Oppenheimer – an American physicist who headed the atom bomb project known as the Manhattan Project. He directed the Los Alamos laboratory that created the first A-bombs and made a considerable contribution to the post-war nuclear arms race. Because of his opposition to the US H-bomb program he was tried and lost his security clearance (допуск к секретным материалам) in 1954. Edward Teller – a Hungarian nuclear physicist who emigrated to the US in 1935. He was known as the father of the H-bomb and never expressed any doubt about it. Because of his fear of Russia he supported 48 the US H-bomb program after the first Soviet A-bomb test. Later he became an enthusiastic supporter of the US Star Wars program. Andrey Sakharov - as a young Soviet physicist he was ordered by the KGB to work on the H-bomb and designed a kiloton weapon that exploded in 1955, only 13 months after the first US H-bomb test. He is regarded as the father of the Soviet hydrogen bomb. In the 1960s, he opposed nuclear proliferation and protested against atmospheric testing of the hydrogen bomb. In 1975 he became the first Russian to win the Nobel Peace Prize. Do you know? The Manhattan Project (1939 – 1945) was the top-secret plan to develop the world's first atomic bomb in the United States. With the discovery of fission in 1939, it became clear to scientists that certain radioactive materials could be used to make a bomb of great power. At the beginning of World War II, news arrived in the U.S. that the Nazis were making an atomic bomb. The U.S. believed they could not allow the Nazis to build such a powerful weapon first and started the Manhattan Project to design a nuclear weapon. In 1942 Enrico Fermi and his associates achieved the first controlled nuclear fission reaction. In 1945 their work resulted in the first test of a nuclear weapon called «Trinity» which was a plutonium device. The first uranium bomb (“Little Boy”) was dropped on Hiroshima on August 6, 1945, killing at least 70,000 people. On August 9, 1945, a plutonium bomb (“Fat Man”) identical to the Trinity device was dropped on Nagasaki, killing at least 35,000 people. 49 Unit 5 Reading 5-А Nuclear Reactor Primer The paper-moderated, ink-cooled reactor is the safest of all. Read Passage 1 and answer the questions below: 1. How much nuclear electricity did nuclear reactors produce worldwide as of July 2008? 2. Which country depends on nuclear power most? 3. In what way do nuclear power plants differ from conventional plants? 4. What are the principal categories of nuclear reactors? 5. How can you account for the difference between them? 1. Nuclear Power in the World Today As of July 2008, there were more than 430 operating nuclear power plants in 31 countries and, together, they provided about 15 percent of the world’s electricity in 2007. Some countries depend more on nuclear power than others. For instance, in France about 77 percent of the country's electricity comes from nuclear power. In the United States, 104 nuclear power plants supply 20 percent of the electricity overall. In Russia, 31 nuclear power plants supply 16 percent of the country's electricity. Actually, a nuclear power plant does not operate differently from a conventional power plant. Both heat water into steam, which drives a turbine generator. The main difference between the two plants is the method of heating the water. While conventional plants burn fossil fuels, nuclear plants derive the heat from nuclear fission, when one atom splits into two. 50 The two principal categories into which nuclear reactors may be divided are: thermal reactors, in which fission is produced by neutrons of thermal energies and fast reactors in which the fission chain reaction is supported by neutrons of energies more than 1 MeV. Read Passage 2 and define the requirements for nuclear reactors in simple terms. Which of the requirements determine the reactor type? 2. Requirements for Nuclear Reactors The principal requirements for а nuclear reactor may be summarized as follows: а) а supply of fissile material (fuel contained in the reactor core); b) in a thermal reactor, a moderator; с) devices for controlling the rate at which the chain reaction proceeds; d) arrangements for removing the heat generated by the operation of the reactor; е) а shield to contain the radiation emitted by the reactor; f) arrangements for removing the radioactive fission products from time to time. Read Passage 3 and answer the questions below: 1. Can you name the three fissile materials suitable for use in a nuclear reactor? 2. Which of them occurs in nature? 3. What is the content of 235U in natural uranium? 4. Which fissile materials do not occur in nature? How are they produced? 5. What are 232Th and 238U called? What materials are referred to as fertile materials? 3. Supply of Fissile Material There are three fissile materials suitable for use in а nuclear reactor 235 U, 239Pu, and 233U. 235U may be used in the form of a naturallyoccurring element, in which it is mixed with a much greater amount of 238 U. The critical amount of uranium for a reactor using the natural metal is several tons and the size of the reactor core may be reduced by using uranium in which the proportion of 235U has been increased, through one of the separation methods. When а uranium reactor is working, neu51 tron capture in 238U leads to the formation of 239Рu which may be extracted chemically from time to time and stored for use in a plutonium reactor. 233U does not occur in nature but may be made by exposing 232 Th to neutron bombardment. Read Passage 4 and answer the questions below: 1. What is the function of the moderator? 2. Why is it necessary to moderate neutrons to thermal energies? 3. What is meant by the fission cross-section? What is the unit of the fission cross-section? (Please refer to the «Do you know?» section to find out where the term «barn» comes from.) 4. What is the fission cross-section for fast and thermal neutrons? 5. What materials can be used as a moderator? 4. Necessity for а Moderator А chain reaction in natural uranium is practicable only if the fast neutrons released in the fission process are reduced to thermal energies before they are lost. The probability that one or another type of interaction between, say, а neutron and а nucleus will occur is usually measured in terms of the "cross section" for that particular interaction. The cross section for fission of natural uranium by neutrons of energy 1.5 MeV is 0.29 barns and is not enough to sustain а chain reaction in a structure of reasonable size. For fission by thermal neutrons, however, the cross section is 3.92 barns, which is quite adequate. For this reason the fuel in а natural uranium reactor is surrounded by moderating material which slows down neutrons rapidly to improve their chances of inducing fission and thus continuing the chain reaction. In a typical thermal reactor, the moderator is ordinary water, which also serves as the coolant. Other choices оf a moderator are possible, such as graphite or heavy water. Read Passage 5 and answer the questions below: 1. What is the power of the reactor limited by? 2. What can happen unless proper cooling facilities are provided? 3. How is surplus heat removed from the reactor? 4. What are the requirements for the coolant? 5. What two purposes does the reactor cooling fluid serve? 6. What parts does the nuclear system consist of? 52 5. Cooling and Energy Conversion The power at which the reactor саn operate is limited only by the capacity of the cooling system to take away the heat which is produced by the fission process. Unless proper cooling facilities are provided, the reactor will disintegrate as a result of thermal stresses. The obvious way to remove surplus heat is to circulate а fluid through the reactor and the requirements for the coolant are easily formulated. It should not capture neutrons or be decomposed by them, it should have а high specific heat and thermal conductivity, and, if а liquid, a high boiling point. The reactor cooling fluid serves a dual purpose. Its most urgent function, as has been pointed out, is to remove the heat from the core. The coolant then transfers this heat for use outside the core, typically for production of electricity. This fluid may be used directly, or it may heat a secondary fluid, to drive а turbogenerator. In all present nuclear generating systems the final fluid is vaporized water, i.e. steam, although this is not the only possibility. In fact it has become conventional to divide the nuclear system into two parts: the nuclear steam supply system (NSSS), which includes the reactor itself and any associated equipment (such as heat exchangers) necessary to produce steam, and the turbogenerator system that is driven by this steam. Read Passage 6 and answer the questions below: 1. What is the function of the control? 2. Why is control necessary? 3. What materials are control rods made of? 4. In what way is the chain reaction controlled? 6. Control The important problem in maintaining а steady chain reaction is that of regulating the rate of neutron production to keep the chain reaction from "dying out" or "running away." This is achieved by using control rods made of neutron-absorbing materials (such as boron) which are automatically pushed in or pulled out of the narrow channels drilled through the reacting fissionable material as soon as the rate of neutron production drops below or exceeds the desired level. 53 Exercise 1. Match the terms on the left with their definitions on the right. 1. Fuel a) The region of a reactor containing the nuclear fuel 2. Moderator b) A device used to produce a chain reaction with uranium to get heat energy for generating electricity 3. Control rods c) Fissile material where the nuclear reactions occur 4. Reactor core d) The fluid that removes heat from the core 5. Coolant e) A machine that is used to convert mechanical energy into electrical energy 6. Shield f) The region of a reactor where steam is generated 7. Heat exchanger g) The material used in a thermal reactor to slow down fast neutrons 8. Turbogenerator h) The structure designed to prevent leakage of radioactive materials 9. Nuclear reactor i) Rods made of materials that regulate the rate of the chain reaction Exercise 2. Match the following Russian and English equivalents. 1. To supply 20 percent of electricity a) Переносить тепло 2. Conventional plants b) Обеспечивать охлаждающие устройства 3. To derive heat from fission c) Увеличить содержание делящегося материала 4. To serve a dual purpose d) Нейтронный захват 5. To regulate the rate of the reaction e) Ядерная паропроизводящая установка (ЯППУ) 6. To keep the reaction from dying f) Не дать реакции выйти из-под out контроля 7. To keep the reaction from run- g) Регулировать скорость реакции ning away 8. Nuclear steam supply system h) Замедлять до тепловых энергий 9. To transfer heat i) Получать тепло в результате ядерного деления 10. To reduce to thermal energies j) Служить двойной цели 11. To provide cooling facilities k) Станции, работающие на традиционных видах топлива 54 12. Neutron capture 13. Fission cross-section 14. To increase the proportion of the fissile material l) Сечение деления m) Не дать реакции остановиться n) Производить 20% электричества Exercise 3. Use Reading 5-A to make sure you know the following words and word combinations. Тепловые реакторы, быстрые реакторы, основные требования к…, источник делящегося материала, замедлитель, теплоноситель, активная зона, управляющие стержни, охлаждающие устройства, защита, отводить избыточное тепло, извлекать, хранить, встречаться в природе, подвергать действию, данное взаимодействие, замедлять нейтроны, поддерживать цепную реакцию, улучшать вероятность, захватывать нейтроны, удельная теплота, теплопроводность, турбогенератор, теплообменник, стало общепринятым, приводить в действие, узкие каналы, падать ниже уровня, превышать уровень, как указывалось, следующим образом, посредством (в терминах), если не…, как только. Exercise 4. Give the derivatives of the words below. 1. To require – требование/потребность. 2. To supply – запас. 3. To moderate – замедление, замедлитель. 4. To proceed – методика (процедура), процесс, обработка, переработка. 5. To arrange – расположение. 6. To contain – содержание, контейнер, защитная оболочка/защитное здание. 7. To suit – подходящий. 8. To occur – встречающийся в природе. 9. To reduce – сокращение. 10. To expose to – воздействие. 11. To practise – практика, практически осуществимая реакция. 12. To measure – мера, измерение. 13. To sustain – самоподдерживающаяся реакция, устойчивое развитие, устойчивость. 14. To cool – теплоноситель, охлаждение. 15. Necessary – необходимость. 55 Exercise 5. Match the pairs of synonyms below. 1) To liberate a) To be destroyed 2) It is apparent b) Quantity 3) To lead to c) To remove 4) To maintain d) To release 5) To generate e) To split 6) To disintegrate f) To moderate 7) Amount g) To result in 8) To break up h) To sustain 9) To enable i) To produce 10) To induce j) To reduce 11) To decrease k) To permit 12) To slow down l) To drive 13) To control m) It is obvious 14) To take away n) To initiate 15) To power o) To regulate Exercise 6. Replace the underlined words with their synonyms from the list below. Use the appropriate form of the verb. To remove, to release, to disintegrate, to moderate, amount, to regulate, to reduce, to lead to, to maintain, to generate. 1. When the nucleus is split, tremendous energy is liberated. 2. 235U is mixed with a much greater quantity of 238U. 3. The size of the reactor core can be decreased. 4. Neutron capture in 238U may result in the formation of 239Рu. 5. 233U does not occur in nature but may be produced by exposing 232 Th to neutron bombardment. 6. This cross-section is not adequate to sustain a chain reaction in a structure of reasonable size. 7. The function of the cooling system is to take away the heat produced by the fission process. 8. But for the cooling fluid, the reactor would be destroyed as a result of thermal stresses. 9. To maintain a steady chain reaction, it is necessary to control the rate of neutron production. 56 10. The fuel in а natural uranium reactor is surrounded by the material which slows down neutrons rapidly to improve their chances of inducing fission Exercise 7. Use Reading 5-A to decide if the statements below are true or false. If they are false, correct them. Use expressions of agreement and disagreement below. I agree with you. That sounds like a good idea. That's right/true. You are right! Absolutely! I don't (really) agree with you. I am not sure about that. That's wrong, I am afraid. Yes, but… 1. There is a great difference in the operation of a NPP and a coalburning plant. 2. The fission cross-section is the probability that a fission event will occur. 3. Fission is more likely to occur if it is caused by fast neutrons. 4. Water, heavy water and graphite are moderators which are commonly used in fast neutron reactors. 5. The most urgent function of the coolant is to prevent the destruction of the reactor as a result of thermal stresses. 6. The NPP consists of two principal systems: the Nuclear Steam Supply System and the turbogenerator system. 7. Control rods keep the chain reaction from «dying out», but they cannot prevent it from «running away». 8. Control rods are made of neutron-moderating materials such as boron. Reading 5-B Chicago Pile-1 You are going to read a passage about the world's first man-made nuclear reactor. Five sentences or parts of sentences have been removed from the text. Choose from the phrases and sentences A-F the one which fits each gap (1-5). There is one extra sentence which you will not need to use. A. led to the atomic pile (nuclear reactor) and the first controlled nuclear chain reaction. 57 B. who actually made uranium "burn". C. a new fissionable element was produced inside the pile during operation. D. nor could it be very useful as а power source. E. "The atomic pile works successfully. The nuclear chain reaction has been achieved." F. it was necessary to mix natural uranium with a large amount of carbon in the form of graphite. The Italian-American physicist Enrico Fermi is sometimes called the Architect of the Atomic Age. It was Enrico Fermi 1). ________. Не was able to do so by utilizing the fact that the effectiveness of fission neutrons in producing the fission оf U235 nuclei increases considerably when they are slowed down. То slow down the original fission neutrons, 2)._______. А large "pile" of graphite bricks with small pieces of natural uranium included in the structure was constructed in great secrecy under the grandstand of the University of Chicago Stadium. And on December 2, 1942, Professor A. Compton telegraphed to Dr. V. Bush in Washington, D.C. "The Italian navigator has landed in the New World. The natives are friendly." In the secret language of the Manhattan Project this meant: 3).________. In the Fermi-pile the natural uranium was so highly diluted by carbon that high efficiency in energy production could not be achieved. Owing to the presence of inactive U238 the chain reaction in the pile could not result in an explosion, 4). ________. But although the energy released in the fission of U235 nuclei was less than the amount necessary to light a small electric bulb, 5). _______. This element was plutonium. Do you know why the first reactor was called a pile? Read the passage below and find out. The Chicago Pile-1was named so because the reactor was more or less a pile of elements stacked on top of one another, primarily made of uranium pellets separated by graphite blocks. Rods coated with cadmium were used to control the reaction. The pile of blocks was held together by wood. An "atomic pile" was a code word for a device that in peacetime would be known as a "nuclear reactor". 58 Reading 5-C Reactor Types Put each of the following words in its correct place in the passage below. Breeder, light water, boiling, thermal reactors, pressurized, rare, heavy, coolant, fertile, fast-neutron reactors, gas, fissile. There are many types of nuclear reactors. Basically, they fall into two broad classes: (a) ______ in which the chain reaction is supported by thermal neutrons, and (b) ______ in which fission is produced by fast neutrons. Thermal reactors are classified according to the type of (c) ______ used. 80% of the commercial reactors in use are cooled and moderated by ordinary water and are known as (d) ______ reactors. Two major types of light water reactors are (e) ______ water reactors, including a Russian version (VVER), and (f) ______ water reactors. The water-cooled graphite-moderated channel type reactor (RBMK, the Chernobyl reactor) is also a light water reactor. Most of the remaining 20% of reactors are cooled by (g) ______ water, like CANDU (the Canadian Deuterium-Uranium reactor), or (h) ______, like the high-temperature gas-cooled reactor. Thermal reactors use only one uranium isotope – U235, which is very (i) ______. Besides, they extract only 1-2 % of the energy from uranium. That is why Russia is interested in fast-neutron reactors which make full use of natural uranium. Fast-neutron reactors can convert (j) ______ materials Th232 and U238 into (k) ______ U233 and Pu239 and produce (or breed) more fuel than they consume. That is why they are called fast (l) ______ reactors. Fast breeder reactors, by creating fuel from nonfissile isotopes, can increase available world nuclear fuel resources. The general trend in the future development of Russian nuclear power is toward the construction of fast reactors. Reading 5-D What is in Nuclear Power? Read the text and choose a suitable heading for each part. There is one extra heading. Translate Parts 5 and 6 in writing. A To err is human B The rest is easy C The fuel 59 D Support and opposition E Be in control F Why the whole is more than the sum of its parts G Einstein was right 1 Commercial nuclear power has been around for nearly half a century. In 1956, the reactor at Calder Hall in north-west England became the first in the world to supply electricity to a national grid. A year later, in Shippingport, Pennsylvania, the US opened its first commercial plant, while France followed suit in 1959 and the Soviet Union in 1964. From the start, great claims were made for the industry: it was going to produce cheap, clean and reliable power. But its critics saw it as costly, polluting, dangerous in the event of an accident, and closely linked to nuclear proliferation. 2 All nuclear power plants use uranium as fuel. With an atomic number of 92 (the number of protons in its nuclei), uranium is the heaviest element found in considerable amounts in nature. It's radioactive. All the uranium on Earth was formed from lighter elements during supernova ехрlоsions billions of years ago. Material from these exploded stars was strewn across space, and eventually some was incorporated into new stars and their orbiting planets. So nuclear power here on Earth harnesses energy that has been stored in uranium for more than 4.5 billion years. Uranium is fissile - its atomic nuclei can be split to release energy. Its most common isotopes are U-238 and U-235. 3 In fission, the nucleus of а heavy element splits and energy is liberated. То trigger the fission of а uranium nucleus, it must be struck by а neutron. This particle is temporarily absorbed, making the nucleus unstable. The nucleus then splits to form two smaller nuclei, releasing two or three more neutrons in the process. Some of the energy of the nucleus is liberated in the form of the kinetic energy of the particles and gamma radiation. Einstein’s famous equation Е= mc2 expresses this fact. The mass of the initial nucleus and the neutron that strikes it is greater than that of the split nuclei and released neutrons, because the missing mass was converted into energy. 60 4 The fact that one free neutron can lead to the release of two or three makes it possible to extract energy in useful quantities from this process, because the neutrons released may trigger а chain reaction - they may collide with other nuclei that in turn split to produce more neutrons, and so on. In а nuclear reactor, the reaction is controlled so that, on average, one neutron from each fission event leads to the release of another. If you allow on average more than one neutron from each event to cause further fission, the neutron flux increases and the power output goes up. 5 So what stops the chain reaction from running out of control? In the reactor core, the rods of natural or enriched uranium are interspersed with control rods, which regulate the rate of fission by absorbing the neutrons. These rods can be raised or lowered to keep the release of energy steady. They are made of neutron-absorbing material, typically boron or cadmium, so when lowered into the core they absorb excess neutrons and slow down the reaction. Raising them speeds it up. Reactors have а fail-safe design: the rods automatically drop into place in an emergency, shutting down the reactor as quickly as possible. The accident at Chernobyl in Ukraine in April 1986 happened during а test in which operators deliberately ignored and disabled safety mechanisms and withdrew most of the control rods. The core overheated and а fire broke out, releasing large amounts of radioactive material. More than 9,000 extra deaths from cancer have since been recorded in the local population. 6 Circulating around the core is а coolant that carries away the heat. Gas-cooled reactors use СО2, as а coolant. Pressurized reactors use water. After the coolant has been heated in the core of the reactor, it is pumped through а heat exchanger where it transfers its energy to water, creating high-pressure steam. The steam is used to turn turbines which drive а generator. This part of а nuclear power station is like any other thermal electricity-generating station. Do you know how the barn got its name? Read the passage and find out. A barn is a unit of cross-section equal to 10-24 cm2. It is more or less equivalent to the cross-sectional area of a nucleus, but refers to the 61 probability of a particular interaction, not a physical area. The origin of the term «barn» is curious. Here is a popular myth about it. Once in December of 1942, a group of nuclear physicists were having dinner in the café of Purdue University. With cigarettes and coffee, the conversation turned to the topic of cross sections. In the course of the conversation it was mentioned that there was no name for the unit of cross section of 10-24 cm2. The tradition of naming a unit after some great man closely associated with the field ran into difficulties, since no such persons could be brought to mind. Failing in this, the names of Oppenheimer and Bethe were tried, since these men had suggested and made possible the work on the problem with which the Purdue project was concerned. The “Oppenheimer” was rejected because of its length, although in shortened form an “Oppy” or “Oppie” would seem to be short enough. The “Bethe” was thought to be confusing because of the wide-spread use of the Greek letter. Since John Barkley was directing the work at Purdue, his name was tried, but the “Barkley” was thought to be too long. The “John” was considered, but it was rejected because of the wide use of the term for purposes other than as the name of a person. Then one of the authors led to the bridging between “Barkley” and “John”. This immediately seemed good and further it was pointed out that a cross section of 10-24 cm2 for nuclear processes was really "as big as a barn” (i.e. an easy target for nuclear bombardment) The term “barn” is spelled just that way, and no capital letter “B” is needed, and that the plural form is “barns” with no letter “e” involved. The meanings of “millibarn” and “kilobarn” are obvious. Unit 6 Reading 6-A Pros and Cons of Nuclear Power Plants Power corrupts, but we need electricity. Nuclear power has a number of advantages, as well as a number of depressing negatives. As far as positives go, nuclear power's biggest advantage is related to the simple fact that it does not depend on fossil fuels. Coal and natural gas power plants emit carbon dioxide into the atmosphere, contributing to climate change. With nuclear power plants, 62 CO2 emissions are minimal. Besides, a properly functioning nuclear power plant actually releases less radioactivity into the atmosphere than a coal-fired power plant. Finally, the cost of nuclear power is not affected by fluctuations in oil and gas prices. As for negatives, nuclear fuel may not produce CO2, but it does cause problems. Historically, mining and purifying uranium has not been a very clean process. Even transporting nuclear fuel to and from plants poses a contamination risk. And once the fuel is spent, you cannot just throw it in the city dump. It is still radioactive and potentially deadly. On average, a nuclear power plant annually generates 20 metric tons of spent nuclear fuel, classified as high-level radioactive waste. When you take into account every nuclear plant on Earth, the combined total amount is roughly 2,000 metric tons yearly. All of this waste emits radiation and heat, meaning that it will eventually corrode any container and can prove lethal to nearby life forms. Eventually, spent nuclear fuel will decay to safe radioactive levels, but it takes tens of thousands of years. Currently, most spent nuclear fuel is stored at reactor sites in specially designed storage pools. In the future, much of this waste may be mixed with glass and transported deep underground. In the meantime, however, this waste has to be stored, monitored and guarded to prevent the materials from falling into the wrong hands. All of these services cost money -- on top of the high costs required to build a plant. Nuclear waste can pose a problem, and it is the result of properly functioning nuclear power plants. When something goes wrong, the situation can turn catastrophic. The Chernobyl disaster is a good example. In 1986, the Ukrainian nuclear reactor exploded, releasing 50 tons of radioactive material into the surrounding area, contaminating millions of acres of forest. The disaster forced the evacuation of at least 30,000 people, and eventually caused a number of deaths from cancer and other illnesses. Chernobyl is still a black eye for the nuclear power industry, often overshadowing some of the environmental advantages the technology has to offer. Exercise 1. Match the following Russian and English equivalents. 1. To be related to safety a) Загрязнять окружающую среду 2. To contribute to climate change b) Следить за состоянием отходов 3. To affect the cost c) Учитывать риск 4. Uranium mining d) Взрыв на реакторе 63 5. To pose a problem (risk) 6. To contaminate the environment 7. High-level waste 8. To take the risk into account 9. To monitor the waste 10. To prevent radiation from escaping 11. The reactor explosion 12. To offer advantages e) Способствовать изменению климата f) Давать преимущества g) Добыча урана h) Препятствовать утечке радиации i) Быть связанным с безопасностью (иметь отношение к…) j) Влиять на стоимость k) Отходы высокого уровня l) Представлять проблему (риск) Exercise 2. Below you will see a list of words related to Reading 6-A. Translate the words and write ten sentences using the words below. Verb 1. To relate 7. To contaminate 8. To die Noun relation relationship relative relativity emission emitter contribution contributor effect efficiency purity impurity mine miner mining contamination death 9. To monitor monitoring 2. To emit 3. To contribute 4. To affect 5. To purify 6. To mine 64 Adjective relative effective efficient pure impure contaminating dead deadly (radiation) monitoring 10. To explode 11. - explosion explosive disaster explosive (substance) disastrous Exercise 3. Put each of the following words in its correct place in the passage below. Nuclear, burn, chain, dangerous, energy, reactor, robot, rods, shielding, turbines, uranium, waste, water. 1. Is nuclear power renewable? [yes/no] 2. Nuclear power stations use _______ as fuel. They need very little fuel, compared to a «fossil» power station because there is much more ______ in nuclear fuel. 3. The ______ reaction inside the ______ creates heat, which turns ______ into steam to drive ______, which drive generators to make electricity. 4. The fuel _____ are safe to handle before they go into the reactor, it is only when they come out that you need to handle them with ______ arms and heavy ______. 5. ______ power stations do not create atmospheric pollution, because they do not _____ anything. However, the small amount of _____ that they do produce is very _______. Exercise 4. Use Reading 6-A to answer the questions below. 1. What is the biggest advantage of nuclear power? 2. What fuels contribute to climate change? 3. Why are nuclear power plants more environmentally friendly than gas- and coal-fired plants? 4. What economic advantage does nuclear power offer? 5. What risk do nuclear power plants pose? 6. What processes in the nuclear industry cause environmental contamination? 7. What is the most important source of contamination? Why? 8. How long does it take for spent nuclear fuel to decay to safe levels? 9. How is spent fuel stored currently? 10. What will happen to nuclear waste in the future? 11. What is the biggest risk posed by nuclear power? 12. What happened at Chernobyl in 1986? 13. What were the consequences of the disaster? 65 Exercise 5. Write a short essay summarizing the advantages and disadvantages of nuclear power using the table below. Use the following plan. 1. Introduction (State the problem). 2. Arguments «for». 3. Arguments «against». 4. Conclusion. Use the following phrases for expressing «for» and against» views: The good/bad thing(s) is/are… One advantage/disadvantage is that… On the one hand… on the other hand… There is one more argument in favor of/against… As far as positives go/As for negatives Besides, however, in the meantime, finally, eventually Advantages Disadvantages Nuclear power costs about the Although not much waste is prosame as coal, so it is not expensive duced, it is very, very dangerous. to make. The waste must be sealed up Does not produce smoke or car- and buried for many years to allow bon dioxide, so it does not contribute the radioactivity to decay. to the greenhouse effect. Nuclear power is reliable, but a Produces great amounts of en- lot of money has to be spent on safeergy from small amounts of fuel. ty, if it goes wrong, a nuclear acci Produces small amounts of waste. dent can be a major disaster. Nuclear power is reliable. Reading 6-B The Problem of Safety Before reading the passage refer to the list of terms below. They will help you understand the text. 1. Routine reactor operation 2. Nuclear accident 3. Volatile fission products 4. Fuel pellets a) Нормальная работа реактора b) Ядерная авария c) Летучие продукты деления f) Топливные таблетки 66 5. Reactor vessel 6. Containment building 7. Economic damage 8. Reactor explosion 9. Probability of an accident 10. Consequences of an accident g) Корпус реактора j) Здание защиты k) Экономический ущерб l) Взрыв реактора m) Вероятность аварии j) Последствия аварии 1. Nuclear fission is the only major non-fossil power source the world can rely on for the rest of the century and for some time afterwards. However, many objections are raised against this source of power. The main concern is expressed over the risk of a release of radioactivity either in routine operation or as a result of a nuclear accident. 2. Some concern is expressed over the fact that nuclear reactors in routine operation release radioactivity through out-flowing liquids. However, most modern fission power plants release a very small amount of radioactivity. 3. A more common fear is that a reactor accident would release catastrophic amounts of radioactivity. Such an accident would involve the release of about half of the volatile fission products contained in the reactor. It is a huge amount since an operating reactor contains about 100,000 tons of fission fragments. 4. Fortunately, the probability of such an event is small. First, the nuclear material in the reactor can never explode under any circumstances, because the content of U-235 in it is 3% (a reactor is not a bomb). Second, an accident could occur only if two or more essential elements in the reactor fail simultaneously. Third, there are at least 3 barriers to a release of radioactivity. They are fuel pellets, a strong reactor vessel and a containment building. The nuclear industry has been very successful in avoiding such accidents. In over 14,500 reactoryears of operation, there have been only three major accidents to nuclear power plants - Three Mile Island, Chernobyl, and Fukushima 5. Anyway, what would be the consequences of a major release of radioactivity? The immediate effects depend on the population density near the reactor and on the wind direction and other weather conditions. Such effects would include: early fatalities radiation sickness 67 latent cancers genetic changes economic damage psychological effects. 6. However, a nuclear accident would not exactly be the end of the world. It is less serious than most minor wars, and these are unfortunately frequent. Some industrial accidents can be more serious, such as explosions and fires in gasoline storage tanks. Compared with other accident risks that our society routinely accepts, the risk from nuclear reactors is very small. Exercise 1. The following six sentences (A-F) summarize the six paragraphs of Reading 6-B. Read the sentences and then match them to the paragraphs of Reading 6-B, 1-6. A. Routine releases are not dangerous because they produce very little radioactivity. B. The risk from nuclear reactors is less serious compared to other man-made risks. C. Many objections are raised against nuclear power. D. The consequences of a major release of radioactivity would include numerous effects. E. The probability of an accidental release is small. F. A reactor would release a catastrophic amount of radioactivity in case of an accident. Exercise 2. In the following sentences the verbs have been omitted. Put in the missing verbs. Use the appropriate verb forms. 1. Many objections ______ against nuclear power. 2. Some concern ______ over the risk of routine releases of radioactivity. 3. Nuclear reactors in routine operation _____ a very small amount of radioactivity. 4. A reactor accident _____ the release of about half of the volatile fission products. 5. Fortunately, the probability of such an event _____. 6. Nuclear reactors ______ to avoid such accidents. 7. Anyway, the consequences of an accident _____ on many factors. 8. The immediate effects _____ early fatalities, radiation sickness and more. 68 9. However, a nuclear accident _____ less serious than many industrial accidents. 10. Our society _____ the risk from nuclear reactors. Exercise 3. Use Reading 6-B to make sure you know the following words and word combinations. Единственный источник энергии, полагаться на ядерную энергетику, вызывать возражения против, выражать опасения по поводу, работа в штатном режиме, в результате ядерной аварии, влечь за собой выброс осколков деления, летучие продукты деления, вероятность события, содержание урана 235, важные элементы реактора, отказывать одновременно, прочный корпус, непосредственные эффекты, плотность населения, погодные условия, острая лучевая болезнь, частые войны, пожары на нефтехранилищах, по сравнению с промышленными авариями, соглашаться на риск. Exercise 4. Listen to the MP3 recording of Reading 6-B and answer the questions below. 1. What is the most reliable source of power currently? 2. What concerns are expressed over nuclear power? 3. What happens at nuclear power plants in routine operation? 4. Why are routine releases of radioactivity not dangerous? 5. What is a more common fear? 6. What would a reactor accident involve? 7. Why is the probability of an accidental release of radioactivity small? Give three reasons. 8. What would the consequences of a major release of radioactivity include? 9. What would they depend on? 10. How can the risk from a nuclear accident be compared to other man-made risks? Do you know? The safety of a nuclear power plant depends on the operation of its various safety systems, from cooling water to the control rods that slow down or stop the nuclear chain reaction. Such shutdowns are known as “scrams”. A scram is a rapid emergency shutdown of a nuclear reactor. The name comes from the safety control rods that were moved by ropes 69 on Fermi's first primitive reactor. To prevent a runaway reaction, a man with an axe (топор) stood ready to literally chop the rope, which would drop the control rods by gravity and stop nuclear fission if a meltdown was going to happen. So scram is an abbreviation meaning “safety control rod axe man”, SCRAM for short. There are no longer axe men at nuclear power plants, but the term remains. Scrams can occur for everything from a loss of coolant to a loss of auxiliary power. Reading 6-C Nuclear Accidents that Shook the World Nuclear power is well known to have a difficult history. Even though it provides us with clean, carbon-free energy, it has revealed its dangerous side with releases of radioactivity and core meltdowns. Here we take a look at five of the most devastating nuclear accidents to date. Windscale (October 10, 1957) Britain’s first nuclear reactor, known as Windscale, was built in the late 1940s. It was designed to produce plutonium for the country’s nuclear weapons program. On October 10, 1957, workers conducting standard maintenance discovered that the reactor’s uranium-filled graphite core had caught fire. Plant operators risked their lives to fight the flames with cooling fans, carbon dioxide and water. The fire finally died out on October 12, but by that time a radioactive cloud was already spreading across the United Kingdom and Europe. While no evacuation occurred, officials stopped the sale of milk from the affected area for about a month. Scientists estimate that radioactive fallout from the Windscale fire caused some 240 cases of cancer. Kyshtym (September 29, 1957) In the years following World War II, the Soviet Union constructed dozens of secret facilities in order to strengthen their nuclear arsenal. One of these, the Mayak nuclear fuel processing plant in the Russian town of Ozyorsk (Озерск), became the site of a major accident. The cooling system in a waste storage tank failed. This caused the radioactive material it contained to overheat and explode. A cloud of deadly particles spread over Ozyorsk and the surrounding region with an area of about some 300 square miles. A week passed before the affected zone’s 10,000 residents were evacuated; because the plant was shrouded in secrecy, they received no explanation for their resettlement. 70 According to estimates, 200 people died of cancer because of exposure to radiation, and thousands more suffered from related illnesses. The Mayak incident is associated with the nearby town of Kyshtym (Кыштым) because Ozyorsk did not appear on any official maps at the time. Three Mile Island (March 28, 1979) The worst nuclear disaster in the United States happened at the Three Mile Island nuclear plant, which is located near Harrisburg, Penn. This accident started with a plumbing breakdown. When a small valve opened to release pressure in the nuclear reactor, it malfunctioned and did not close. This led to a leakage of the cooling water and the core started to overheat. The systems monitoring the reactor’s conditions provided incorrect information. Hence, the reactor operators shut down the emergency water which could have cooled the core. As the core started to overheat, it gradually reached 4,300 degrees Fahrenheit and the plant had a near meltdown. But the full meltdown was prevented by the plant operators who were instructed to turn on the supply of water. The reactor’s conditions were stabilized. According to the Nuclear Regulatory Committee, there were no deaths due to the accident, though some individuals received radiation doses of as high as 100 millirems. The Three Mile Island nuclear accident left a huge impact on the American people’s attitude towards nuclear power. Chernobyl (April 26, 1986) The accident in Chernolyl, Ukraine, involved a reactor that on April 26, 1986, exploded after a series of mistakes by Soviet operators during an experiment at one of the facility’s four reactors. The experiment created a sudden power surge, which in turn led to a series of explosions that blew the 1,000-ton steel top off of the reactor. A cloud of radioactive material spread over the nearby town of Pripyat which was evacuated only 36 hours after the explosion. Soviet officials tried to keep the accident a secret, but on April 28 Swedish radiation monitoring stations reported radiation levels 40 percent higher than normal. The radioactive material spread as far as the UK. In the opening days of the crisis, 32 people died at Chernobyl and dozens more suffered radiation burns. The accident caused countless birth defects and started a thyroid cancer epidemic in the region. The radiation that escaped into the atmosphere contaminated millions of acres of forest and farmland. 150,000 people had to be permanently re71 located. In 2000, the last working reactors at Chernobyl were shut down and the plant was officially closed. Fukushima (March 11, 2011) An 8.9 magnitude massive earthquake and the following tsunami led to disruptions in the cooling system of the nuclear plant located along Japan’s northeast coastline. They destroyed the electrical grid that powered the reactor, including its water-circulating system. A backup diesel generator was also destroyed. This accident triggered several explosions in the different reactors at the complex. This led to a massive evacuation in the area. The latter three severe accidents occurred during more than 14,000 reactor-years of operation. Of all the accidents and incidents, only the Chernobyl and Fukushima resulted in significant radiation doses to the public. Other accidents were completely confined to the plant. Radiation should be respected, not feared, experts say. Of course, there is no such thing as zero risk. But the goal for nuclear power plant operators and builders is to reduce the risk of a serious accident, like the ones at TMI and Chernobyl, to less than one in 100,000 or more years. Exercise 1. Use Reading 6-C to write brief notes about each of the nuclear accidents described in the text. When October 10, 1957 September 29, 1957 March 28, 1979 April 26, 1986 March 11, 2011 Where What Exercise 2. Read about different types of reactor accidents and prepare to discuss their consequences. A loss-of-coolant accident (LOCA) occurs if for some reason the flow of water is stopped or slowed -- for example if a pipe breaks. Then the fuel rods do not receive adequate cooling and begin to overheat. A core meltdown is caused by an overheating of the nuclear fuel rods as a result of loss of cooling. Then the fuel rods can become so hot that they can melt. If not managed effectively, a meltdown can damage 72 or destroy the reactor and release extreme levels of radiation into the environment. The term China Syndrome describes a nuclear reactor accident characterized by a severe meltdown of the core components of the reactor, which burn through the reactor vessel and the containment building, then through the crust and body of the Earth and reach the opposite side of the Earth, which in the United States is popularly said to be China. Reading 6-D The "Atoms for Peace" Agency The International Atomic Energy Agency, known as the IAEA (МАГАТЭ), is the world's center of cooperation in the nuclear field. It was set up as the world´s "Atoms for Peace" organization in 1957 as a United Nations agency. The IAEA works for the safe, secure and peaceful uses of nuclear science and technology. The work of the IAEA covers three fields: Safety and Security (Ядерная безопасность и физическая защита ядерных объектов); Science and Technology (Ядерная наука и технология); and Safeguards and Verification (Гарантии и контроль над ядерной деятельностью государств, не обладающих ядерным оружием). In these three areas, the Agency works to develop the use of nuclear technology for peaceful purposes, and at the same time to prevent using nuclear energy for military purposes. The IAEA is the world's leading nuclear non-proliferation agency. The Agency plays an important role in ensuring compliance with the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) (Договор о нераспространении ядерного оружия (ДНЯО)) of 1968. The IAEA has its headquarters in Vienna, Austria. The agency was headed by Hans Blix of Sweden from 1981 to 1997, and by Mohammed El Baradei of Egypt from 1997 to 2009. El Baradei won the Nobel peace prize in 2005 for his work at the IAEA. Since 2009, the agency has been headed by Yukiya Amano of Japan. Please note the difference: Safety focuses on unintended conditions or events leading to radiological releases from authorised activities. Security focuses on the intentional misuse of nuclear or other radioactive materials to cause harm. 73 Safeguards focus on stopping activities that could lead to proliferation of nuclear weapons. Nuclear Power Quiz Some people think of nuclear power as a threatening menace, while others see it as a long-term source of greener electricity. What do you know about nuclear energy? Test yourself. 1. Nuclear power plants produce energy through: A. induced fission B. induced fusion C. beta decay 2. Uranium-235 splits when _______ hits its nucleus: A. a proton B. a neutron C. an electron 3. Uranium is a fairly common element on Earth, but it was originally formed: A. on the moon B. in stars C. on asteroids 4. Fission produces lots of energy because: A. Some of the subatomic particles disintegrate, releasing lots of energy. B. The fission products and neutrons have more mass than the original atom. C. The fission products and neutrons have less mass than the original atom. 5. How many nuclear power plants are there worldwide? A. several dozen B. several hundred C. a few thousand 6. The main difference between a nuclear plant and an oil- or coal-fired plant is: A. the size of the generator B. the shape of the generator C. the fuel 74 7. Where was the first nuclear reactor constructed? A. the Gabon Republic in South Africa B. the Department of Defense's New York facility C. under the stands of the University of Chicago's old baseball stadium 8. To prevent overheating, control rods: A. move extra uranium out of the way B. absorb excess neutrons C. create a barrier between different parts of the fuel 9. What prevents the escape of radiation in the event of an accident at a nuclear plant? A. the containment structure B. cooling towers C. control rooms 10. What are some of the difficulties with nuclear power? A. dealing with spent fuel, which is toxic B. transporting fuel to the power plant C. preventing nuclear accidents D. all of the above 75 APPENDIX LINKING DEVICES Linking devices are important because they show how the parts of the sentence or of the text relate to each other. They are like signposts on a road, because they help the reader understand where he or she has come from, or where he or she is going to. Exercise 1. Translate the following sentences. Pay attention to the use of «as». as – как, в качестве – предлог e.g.: He works as an engineer. as – 1) как (в вводных предложениях и оборотах) e.g.: As you know… As mentioned above… 2) когда, в то время как, по мере того как e.g.: As the temperature rises… 3) так как, поскольку e.g.: As the problem is too difficult… as… as – так же… как, такой же… как NB! as soon as – как только as long as, so long as – пока, если только as to/as for – что касается as well as – так же, как as well – также as early as the 19th century – еще, уже в 19 столетии as far as we know - насколько нам известно as yet – до сих пор 1. As you know, it was E. Fermi that started up the first nuclear reactor in 1942. 2. As mentioned above, light water serves both as a coolant and as a moderator in the LWR. 3. Radioactive material becomes less radioactive as time goes by. 4. As radiation continues the level of radioactivity falls exponentially. 76 5. Radioactivity decreases with time as radioactive isotopes decay into stable, non-radioactive ones. 6. As uranium nuclei split, they release more neutrons, which can be used to split further nuclei. 7. Spent fuel is treated as high-level waste. 8. As the speed of light is extremely great, we cannot measure it by ordinary means. 9. As the temperature rises, the total energy radiated by a body increases. 10. The mass of the proton is small. It is nearly 2000 times as heavy as that of the electron. 11. As the atom fissions, heat and more neutrons are released by the atom. 12. As soon as this occurs, the two isotopes are readily separated both by chemical and physical means. 13. Alpha-particles continue to exist as long as they move fast enough. 14. Like all other subatomic particles, electrons have wavelike as well as particle-like properties. 15. As a gas is cooled, it loses heat as well as energy. 16. As far as we know, the supplies of oil will not last very long. 17. The concept of the breeder reactor is almost as old as the idea of the nuclear chain reaction. 18. The chain reaction in the fuel stops as soon as the fuel is removed from the reactor. 19. As discussed above, the neutrons released in the fission process are slowed down as they strike the hydrogen nuclei in the water coolant. 20. In any nuclear power reactor heavy metal atoms are consumed as the fuel “burns”. 21. Every chemical change involves a physical change as well. 22. In nature uranium occurs as a mixture of two isotopes: U235 and U238. 23. Any spent fuel will still contain some of the original U235 as well as various plutonium isotopes. 24. As the name suggests, dry cooling relies on air as the medium of heat transfer. 25. This process creates carbon dioxide as a by-product. 77 Exercise 2. Translate the following sentences. Pay attention to the use of «because». because – потому что, так как (союз, вводит придаточное предложение) because of – из-за, вследствие, благодаря (предлог) 1. Because the neutron is neutral, the positive charge of the nucleus does not affect it. 2. Because of their electric charge protons do not penetrate matter as easily as neutrons do. 3. Because of their energy the molecules of a liquid are always in rapid motion. 4. Friction causes losses because part of the useful energy is transformed into useless heat because of friction. 5. Because γ-radiation has no weight, it is very penetrating. 6. Many people are opposed to nuclear power because of fear associated with radiation. 7. Nuclear fusion has attracted scientists because of its tremendous amount of energy. 8. Fusion power is difficult to achieve because of the tremendous complexity of the process. 9. Because the world’s uranium supply is limited, it is necessary to develop alternative energy sources. Exercise 3. Translate the following sentences. Pay attention to the use of «one». one – один, единица (числительное) one (ones) – слово-заменитель существительного one – вы (местоимение) NB! once – 1) как только (союз), 2) однажды (наречие) at once - сразу 1. One should remember that one form of energy can be transformed into another one. 2. This value is equal to one. 3. One of the neutrons must trigger another fission. 78 4. The time comes when one has to make a decision. 5. This particle has a mass the same as that one. 6. One can express the same information in terms of the decay constant. 7. Carbon emissions can be reduced by simply replacing fossil fuel power plants with nuclear ones. 8. One neutron is needed to continue the chain reaction, one must convert a fertile nucleus into one that is fissile. 9. Many countries are replacing their older plants with new ones. 10. Another source of radioactivity is when one form of a radioisotope changes into another one, or isomer releasing a gamma-ray in the process. 11. Once the fission reaction was experimentally confirmed in 1939, scientists in many countries started nuclear fission research. 12. Once started, the chain reaction must be controlled. 13. Once the nucleus gives off some type of radiation, the original atom changes into a new one, with different nuclear properties. Exercise 4. Translate the following sentences. Pay attention to the use of «only». only – только (частица) the only – единственный (определение к существительному) 1. Hydrogen is the only element containing one electron. 2. The only fissile material found in nature is U235. 3. Fossil fuel is not the only source of energy. 4. Nuclear power should only be used for peace. 5. This paper only deals with the safety of nuclear reactors. 6. “We can’t go back, we can only go forward”, said the scientist. 7. Inherent or passive safety depends only on physical phenomena, such as convection, gravity or resistance to high temperatures. 8. Nuclear power is the only technology that takes care of its wastes. 79 Exercise 5. Translate the following sentences. Pay attention to the use of «since». since – с, после (какого-то времени) – предлог e.g.: Since the discovery… since - с тех пор, как (союз времени) e.g.: Since radioactivity was discovered… since – так как, поскольку (союз причины) e.g.: Since the atom is electrically neutral,… since – с тех пор (наречие) e.g.: This hasn’t happened since. 1. Radiation has been with us since the beginning of the earth. 2. Since the discovery of radioactivity in 1896 the use of radiation has become widespread. 3. Scientists have studied the use of radioisotopes since the beginning of the 20th century. 4. Since Rutherford’s time radiations have been classified into 3 basic types. 5. Since an atom has an equal number of protons and electrons, it is electrically neutral. 6. Since the neutron is uncharged, it is an ideal projectile for nuclear bombardment. 7. Since the neutron is uncharged, it is not affected by the charged electrons and protons. 8. Since electrons have a negative charge, atoms that lose electrons become positively charged ions. 9. Since an atom loses an electron, it becomes positively charged. 10. Since radiation presents health problems, it must be handled with great care. 11. Fossil fuels are bad for the environment since they cause pollution. 12. Fusion power has been under investigation since the 1950s. 13. Since the fuels we use today are limited, scientists are looking for new ways to obtain energy. 80 Exercise 6. Translate the following sentences. Pay attention to the use of «that». that (those) – тот, та, то (те) – указательное местоимение that - что (союз) that – который (союзное слово) that, so that, in order that – чтобы (союзы цели) that – то, чтобы; так, чтобы – союз (вводит придаточное предложение) that is – то есть that (those) – слово-заменитель …is that… – состоит в том, что… 1. Nuclear specialists say that nuclear power is the only available method of producing clean electricity. 2. An important feature of the nuclear reactor is that the products of reactor operation are radioactive. 3. As the speed of the particle approaches that of light, its mass increases. 4. Radioactivity is readily measurable and its effects are well understood compared with those of chemical substances. 5. Accident statistics in nuclear power should be compared with those from coal-fired electricity generation. 6. All the types considered are thermal reactors, that is, the neutrons in them are moderated. 7. A number of the new designs are based on passive safety, that is, on natural forces. 8. Electricity is important for many reasons. One is that it helps increase our standard of living as the population grows. 9. The total number of operations that that device can perform is great. Exercise 7. Translate the following sentences. Pay attention to the use of «number». a number – число, номер (существительное) a number of – (целый) ряд, набор, несколько the number of – число 81 1. Since the atom is electrically neutral, the number of electrons is equal to the number of protons. 2. A number of important discoveries in the nuclear field were made in the 20th century. 3. Actually, the number of discoveries was so great that this resulted in the nuclear technology. 4. There are a number of technologies for reprocessing the spent fuel. 5. The International Atomic Energy Agency has a number of nuclear energy programs. 6. The number of fuel assemblies in the reactor depends on the reactor power output. 7. A number of instruments can detect and measure radiation. 8. The number of steps for the atom to decay is well known. Exercise 8. Translate the following sentences. Pay attention to the use of «result». a result – результат (существительное) to result – возникать (глагол) to result in – приводить к… (глагол) to result from – проистекать из, быть результатом чего-либо (глагол) as a result – в результате, как результат 1. The results of the reactor safety study were published in 1974 in the document known as the Rasmussen Report. 2. Each nuclear fission in the reactor produces one additional fission, which results in the chain reaction. 3. The new evolutionary designs have already produced good results. 4. They resulted in improving safety and reliability, simplifying the operation and reducing the cost. 5. The Chernobyl accident resulted from lack of safety culture. 6. Radioactivity decay results in the release of ionizing radiation. 7. A major loss-of-coolant accident (LOCA) can result in a core meltdown. 8. Carbon dioxide and sulphur dioxide are produced as a result of coal-fired electricity generation. 82 9. There have been a number of accidents in reactors but none of these resulted in loss of life or long-term contamination. 10. Lack of national resources in Japan resulted in a major nuclear program. Exercise 9. Translate the following sentences. Pay attention to the use of «before». before – до (предлог) before – до того как, прежде чем (союз) e.g.: Before the experiment… before – прежде (наречие) e.g.: before the experiment starts… 1. Before the experiment you should read the instructions. 2. Before you start the experiment, you should study the instructions. 3. Before the idea becomes a reality, there is much experimentation to be carried out. 4. Man always wants to know something which has never been known before. Exercise 10. Translate the following sentences. Pay attention to the use of «after». after – после (предлог) e.g.: After the experiment… after – после того как (союз) e.g.: After the experimentation was completed… 1. After completing the experiment the scientists obtained important results. 2. After the experiment was completed, the scientists obtained important results. 3. Fission products are the smaller atoms left after the atom undergoes fission. 4. Fission products continue to give off heat and radiation after fission has stopped. 83 5. After the Chernobyl accident changes were made in both the reactors themselves and in the control systems. 6. The amount of energy before and after transformation is always the same. Exercise 11. Translate the following sentences. Pay attention to the use of «if, unless, provided, in case, until». if – если (условный союз) unless – если не… (условный союз) provided (that) – если, при условии, что… (условный союз) in case – если, в случае если (условный союз) NB! until – 1) до тех пор, пока не… (союз времени), 2) до (предлог времени) 1. A chain reaction can be sustained if there is a critical mass of fissile material available. 2. An atom with an electrical charge is called an ion. The charge is positive if the atom has more protons than electrons and the charge is negative if the atom has more electrons than protons. 3. The particle will not be absorbed by the target nucleus unless its velocity corresponds with one of the energy levels of the nucleus. 4. The neutron is likely to be captured by the nucleus provided it is in resonance with an energy level of the nucleus. 5. Radioactive isotopes must be handled with great care in case they cause radiation damage. 6. Unless urgent steps are taken to reduce the use of fossil fuels, the consequences could be catastrophic. 7. Until the programmers learn to think clearly, we will probably have to live with computer bugs. 8. If a substance has a long half-life, it will not give off many bits of radiation in a second – it will have “low activity”. 9. As the reaction proceeds, the temperature rises, until a steady state is reached. 10. Unless they make this assumption, they won’t obtain the proper data from the experiment. 11. In case ECCS should fail, further protection barriers become operative. 84 12. Fast breeder reactors will be introduced commercially, but not until 2050. 13. No exposure to radiation should be allowed unless it produces a net benefit to those exposed or to the general public. Exercise 12. Translate the following sentences. Pay attention to the use of «like». to like – нравиться (глагол) like – подобный (прилагательное) like – как, подобно (союз) unlike – в отличие would like – хотелось бы 1. The scientist liked the idea of making another experiment. 2. Like other subatomic particles, electrons have wavelike as well as particle-like properties. 3. A reactor simply cannot explode like a nuclear bomb. 4. Like all industries, the nuclear generation of electricity produces waste. 5. Unlike fossil-fuel power plants, NPPs do not produce carbon dioxide. 6. Plutonium, like uranium-235, is fissile and can sustain the chain reaction. Exercise 13. Translate the following sentences. Pay attention to the use of «both…and…». both – оба both… and – как…, так и 1. In both cases there is no loss of energy. 2. Both isotopes can be effectively isolated and stored safely. 3. Both scientists studied this phenomenon. 4. Both reactors use light water both as a coolant and as a moderator. 5. The advanced reactors are designed to improve the safety of people – both the operators and the general public, if and when things go wrong. 6. The health effects of exposure both to radiation and to chemical agents must be considered in relation to time. 7. The new design reduced both the construction and generation costs. 85 8. This reactor is designed for both uranium and plutonium fuel. 9. Both fission and fusion seem promising for space propulsion applications. 10. Both solar power and wind power are already used, though on a small scale. 11. Both protons and neutrons can be obtained in a free state. Exercise 14. Translate the following sentences. Pay attention to the use of «either… or…», «neither…nor…». either – также (в отрицательных предложениях) – наречие either of – любой (из двух), один (из двух), и тот и другой, ни тот ни другой either – или (союз) either… or – либо… либо, ни… ни (в отрицательных предложениях) neither… nor – ни… ни neither – никакой, ни один (прилагательное) neither – также не (наречие) 1. Either of these two particles may be of use. 2. Depending on the plant design, the water either boils in the reactor vessel or in a separate circuit. 3. High-level waste (HLW) may be either the used fuel itself or the waste separated in reprocessing it. 4. In either case the amount is small. 5. Either way, after 40-50 years the heat and radioactivity fall to one thousandth of the original level. 6. Most star products are either stable nuclei or nuclei decaying via electron capture. 7. Neither of the two values is correct. 8. Neither of these phenomena has yet been studied. 9. The universe is neither solid, nor liquid, nor gaseous. 10. Neither of these modes of radioactive decay is important to nuclear reactors. 86 ИСПОЛЬЗУЕМЫЕ ИСТОЧНИКИ 1. Смирнова С.Н. Учебное пособие «История атомных идей». – ОИАТЭ, Обнинск, 1990. 2. Статьи из английских и американских периодических изданий «Scientific American», «Nuclear Science and Engineering», «Nuclear Europe Worldscan» и др., 2007–2012. 3. Ресурсы Интернет (www.wired.com, www.worldnuclear.org, www.iaea.org, www.energy.gov и т.д.). 4. Zoellner T. Uranium: War, Energy and the Rock that Shaped the World. – Viking Penguin, 2009. 87 СОДЕРЖАНИЕ Introduction .................................................................................................... 3 Unit I. The Structure of the Atom. The Atom Quiz ......................................... 4 Reading 1-A. The Thomson Atom: Discovering the Electron ......................... 5 Reading 1-B. The Rutherford Atom ................................................................ 8 Reading 1-C. Quantum Mechanics Throws Light on the Atom: The Bohr Model ............................................................................................................. 12 Unit 2. Reading 2-A. Quark Hypothesis ...................................................... 19 Reading 2-B. Classification of Quarks ........................................................ ..23 Reading 2-C. The Mysterious Neutrino ........................................................ 24 Reading 2-D. Nanotechnology ...................................................................... 25 Unit 3. Reading 3-A. Radiation and Radioactivity..................................... ..27 Reading 3-B. Alpha, Beta and Gamma Rays ............................................... ..30 Reading 3-C. The Discovery of Radioactivity .............................................. 31 Reading 3-D. How Dangerous is Radiation ................................................... 34 Reading 3-E. Radiation Facts ........................................................................ 36 Nuclear Radiation Quiz................................................................................ 37 Unit 4. Reading 4-A. Nuclear Fission and Chain Reaction .......................... .39 Reading 4-B. Emission of Neutrons ............................................................. .42 Reading 4-C. A Walk in the Snow ................................................................ 44 Reading 4-D Architect of the Nuclear Age.................................................... 45 Reading 4-E. Nuclear Scientists and the Nuclear Bomb ............................... 48 Unit 5. Reading 5-A. Nuclear Reactor Primer ............................................. .50 Reading 5-B. Chicago Pile-1 ........................................................................ .57 Reading 5-C. Reactor Types.......................................................................... 59 Reading 5-D. What is in Nuclear Power? ...................................................... 59 Unit 6. Reading 6-A. Pros and Cons of Nuclear Power Plants..................... .62 Reading 6-B. The Problem of Safety ............................................................ .66 Reading 6-C. Nuclear Accidents that Shook the World ................................ 70 Reading 6-D. The «Atoms for Peace» Agency .............................................. 73 Nuclear Power Quiz ..................................................................................... 74 Appendix. Linking Devices ........................................................................... 76 Используемые источники ......................................................................... 87 88