Аврамова NUCLEAR ENGLISH 2013

Exercise 2. Use the notes given below to write a description of three types of rays.

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 X- ray 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-the- dark 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 radio-

active 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 urani- um-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 at-

39

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 convert-

ed 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.

Now complete these sentences using the expressions above. Uranium-238 (U-238) undergoes ______ very slowly and has an ex-

tremely 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