Chernobyl 25 years on: learning the lessons of nuclear disaster
Twenty-five years ago, the Chernobyl nuclear plant in the Ukraine suffered a catastrophic explosion. The real lessons are still being learned, says Roger Highfield.
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A Communist-era statue of Lenin stands in the grounds of the deserted Chernobyl nuclear reactor. Photo: AP
When my visit to Forsmark nuclear power station was cancelled at the end of April 1986, I was impressed by the candour of my Swedish hosts. I was with a group of Scandinavian journalists who were about to enter the plant, 50 miles north-east of Uppsala, when we were told that a nuclear leak had set off an alarm.
We felt a mix of surprise, excitement and unease when, later that day, the Swedish Nuclear Power Inspectorate told us that the pattern of radioactive isotopes in the leak was nothing to do with Forsmark – in fact, it was typical of a Soviet reactor design, known as an RBMK. It would take Moscow almost three days to admit that, on April 26, there had been an accident at the Chernobyl nuclear facility in the Ukraine, 1,000 miles away. Staff at the number four reactor had been running tests at low power to find out how well they could cope with a temporary shutdown of the cooling system. Things went badly wrong: the Russians tried to shut the plant down, but instead the reaction accelerated, with disastrous consequences.
Since then, Chernobyl has been the benchmark by which all other nuclear accidents have been judged – especially the one at the Fukushima in northern Japan, which suffered major damage from the earthquake and subsequent tsunami on March 11.
Luckily, the reactors in Fukushima were much safer designs. The working reactors in the plant automatically shut down as soon as they felt the earthquake, by inserting control rods, so the reactions in their cores began slowing within seconds. By contrast, Chernobyl was actually running – albeit at low power – at the time of the accident.
Crucially, Chernobyl had a “positive void coefficient’’: the formation of steam bubbles cut the ability of the liquid water coolant to absorb neutrons, which in turn increased the reactor’s power output. This caused yet more water to flash into steam, increasing the power up to 1,000-fold. The result was an explosion inside the reactor itself (unlike Fukushima, where hydrogen gas generated as the fuel melted detonated outside the reactors).
In the Ukraine, 1.5 tons of highly radioactive material were blasted many thousands of feet into the air. The damaged unit burned for 10 days, spewing out more radioactive material and a plume that could be detected around the globe. Even though Fukushima has been categorized as a Level 7 accident, the highest on the scale, the amount of radioactive material that has escaped is far smaller: Japan’s Nuclear and Industrial Safety Agency estimates that the plant has spilled between 370,000 and 630,000 terabecquerels of radioactivity into the environment, while Chernobyl released a total of 5,200,000.
But what will be the long-term impact? In the Ukraine, even today, a 19-mile exclusion zone remains around the plant, which includes the ghost town of Pripyat. Altogether, 350,400 people were evacuated and resettled from the most severely contaminated areas. Yet the health consequences of such disasters are far harder to calculate. Five years after Chernobyl, a 1,500-page report, drawing on the work of 200 health experts from 25 countries, attempted to assess the effect on 825,000 people in the most contaminated areas, Byelorussia, Russia and the Ukraine.
Radiation poses two distinct threats. One is from the huge doses encountered by firefighters and plant workers that cause burns and radiation sickness: in Chernobyl, these included the 600,000 so-called liquidators brought in to clean up after the accident and the 3,500 “biorobots”, soldiers and reservists who had to dart – with primitive protection – to the edge of the burning reactor to clear debris, in searingly radioactive conditions that disabled real robots. Even after working for less than a minute, many of the men complained of nosebleeds, exhaustion and a metallic taste.
The second threat is the long-term impact, in the shape of additional cancers – such as the estimated 1,900 extra cancers seen over the years in those exposed to the blasts at Hiroshima and Nagasaki, some of whom received significantly more radiation than those around Chernobyl.
In the Ukraine, two people died immediately after the blast and another 29 died in hospital over during the next few days, but the longer-term impact was far harder to measure. Hot spots were dotted around where rainfall washed radioactivity out of the plume of fallout: even today, Welsh sheep farmers are still dealing with the problem. And studies of the impact were hindered by the reluctance of the Soviet Union to release details of the calamity: it was only in 1989 that official contamination maps were released.
Two decades ago, Prof John Gittus of the Royal Academy of Engineering advised the Government that there could be around 10,000 fatalities. Today, some environmental groups put the toll well into six figures. However, Professor Wade Allison of Oxford University is adamant that “the only deaths that have been firmly established, either individually or statistically, are the 28 victims of Acute Radiation Syndrome and 15 cases of fatal child thyroid cancer”.
The mainstream view lies between these extremes. Dr Jim Smith of the University of Portsmouth prefers to cite a 2006 study by Dr Elisabeth Cardis of the International Agency for Research on Cancer, which predicted that by 2065, about 16,000 cases of thyroid cancer and 25,000 cases of other cancers may be expected, compared with several hundred million cases from other causes. Thyroid cancer in particular is treatable, so the latest estimate of the death toll from the UN’s Chernobyl Forum puts the death toll among the most exposed populations at around 4,000.
When it comes to Fukishima, the earthquake and tsunami killed two workers and injured many more. There were further casualties from the hydrogen explosions, and at least one worker was sent to hospital after an overdose of radiation. But as Prof Richard Wakeford of the University of Manchester explains, there will be difficulty getting reliable estimates of radiation doses, which are crucial for predictions of excess cancers.
As far as the workers are concerned, a dose at the emergency limit of 250 mSv would produce a lifetime risk of serious cancer of around 1 or 2 per cent. Therefore, if 100 workers received this dose then one or two additional serious cancers would be expected, in addition to the 20-25 which would develop in the normal course of things. For those further away, the risk would be negligible: “if the dose to the thyroids of young children was successfully limited by the various countermeasures,” says Prof Wakeford, “I doubt whether any effect could be detected”.
An editorial published in Lancet Oncology to mark the anniversary argues that the accident at Fukushima will at the very least offer a much better opportunity than Chernobyl to study the health consequences of a major nuclear accident – not just from radiation, but from psychological factors such as stress.
There is also growing evidence that the effects of radiation can be passed to future generations. Studies of mice by Prof Yuri Dubrova, of the University of Leicester, reveal that large doses of radiation can make the genetic code more likely to suffer mutations, and that this propensity can be passed down the generations in the “germ line”, the genes contained in sperm and eggs.
Although there have been claims that these effects have been seen in the families of Chernobyl clean-up workers, the jury is still out on whether people react in the same way – after all, such effects were not observed in the A-bomb survivors.
The long-term cost is not just medical, however. The Tokyo Electric Power Company hopes to shut down the Fukushima reactors completely within nine months, but experience at Chernobyl suggests that the subsequent cleanup could take decades. There, efforts are still under way to raise just over a billion dollars to complete the construction of a huge long-term shelter to replace the so-called sarcophagus, a crumbling protective structure which was hastily thrown up over the reactor in the months after the accident. The replacement will be the largest of its kind in the world, more than 100 meters high, 250m wide and 160m long. The great hanger will serve as an enduring monument to the world’s worst civil nuclear accident, and to our remarkable state of ignorance about the impact of nuclear fallout.
Самостійна робота №15
Теорія:Правила узгодження часів. Непряма мова. Інфінітив.
Текст: “City garbage: problems and solutions”
Ex.1 Read and translate following international words paying attention to the parts of speech.
Horde n; utilize v; conveyer n; extract n; briquette n; cylinder n; diameter n; rotate v; ballast n; vertical a; ceramics n;
Ex.2 Read and remember the following words:
Rid of – звільняти
Rodent – гризун
Handle – керувати
Tip – смітник, звалище
Smelt – плавити
Ripen – зріти, визрівати
Sift – просіювати
Ex.3 Check your knowledge the following words with of the terminological dictionary:
Penetrate, separator, extract
Ex.4 Give the correspondence to the English word combinations:
1. waste disposal 1. стрічковий конвеєр
2. decomposition products 2. бітумні смоли
3. consumer goods 3. компостна маса
4. belt conveyer 4. біопаливо
5. compost mass 5. продукти розпаду
6. bituminous resins 6. біотермічні барабани
7. biological fuel 7. споживчі товари
8. biothermal drums 8. видалення відходів
Ex.5 Give the correspondence to the Ukrainian word combinations:
1. calculation
2. calculated
1. незлічуваний 3. incalculable
4. calculator
5. calculating
1. saturation
2. насичений 2. saturated
3. unsaturated
1. separation
3. розподілювач 2. inseparable
3. separator
4. separated
Ex.6 Read the text and give its contents in some sentences.
City garbage problems and solutions
Almost everything that is produced for human needs, with time becomes garbage. All sorts of methods have been tried to get rid of refuse. It has been buried, removed as far as possible from population centers. Nevertheless, even in antiquity Rome lost the “battle”: garbage filled its famous Forum.
In our time the problem of domestic waste disposal has acquired a global nature. Cities with populations of several million form Everest’s of garbage. Every urbanite throws away nearly a tone of unwanted things annually. They wind up in the city garbage dumps, which take up hundreds of hectares of land, putting it out of useful circulation. Moreover, all such dumps are unsanitary. The mountains of garbage attract incalculable hordes of rodents and birds, which spread decomposition products. Rain water becomes saturated with noxious substances which subsequently penetrate into underground water and poison them. Not only does grass not grow on the sites of former dumps, but construction work and the laying of supply lines in these areas have to be banned for 50 to 100 years.
Many useful elements, including those of organic origin, are irretrievably lost in garbage dumps. While taking them from nature and in enormous quantities, man gives nothing back to it. On the contrary, he keeps on taking in order to turn out new consumer goods. Eventually, this can seriously upset the ecological balance.
The most effective method of waste disposal is to utilize it, in other words, to process it industrially.
How is this done?
Different countries handle this engineering problem in different ways. Experts have developed many production processes which make it possible to reconvert mountains of garbage into substances that are of crucial importance to industry and agriculture. Among such enterprises is the St. Petersburg automatic plant which processes solid domestic waste. It alone “gobbles up” 35-40 per cent of the city’s tips – 900,000 cubic meters.
The garbage is first fed to belt conveyers, where magnetic separators extract ferrous metals from it, which are subsequently pressed into compact briquettes and shipped to metallurgical plants for resmelting. Domestic wastes, in particular tin cans ( and other discarded objects as well), also contain valuable materials like tin, copper, zinc and brass. Until recently they were extracted in the metallurgical plants which receive the briquettes, but now this is being done in the automatic plant itself – in special newly built departments.
Refuse relieved of metal then goes into biothermal drums – enormous cylinders up to 60 meters long and four meters in diameter. They slowly rotate, mixing the waste. The air which is fed into the drums provokes an intensive aerobic process. Under the action of microorganisms all the garbage’s organic components decompose. The temperature of what is no longer waste, but is known as the compost mass, rises to 60 – 70 C. As a result, the disease-producing microbes die and the substance in the drums becomes harmless.
In 48 hours the compost mass ripens. Nevertheless, it still contains a wide variety of particles and fragments which biothermal treatment leaves unchanged. In order to dispose them the mass is sifted through giant sieves, where the material processed in the biothermal drums is separated into compost and ballast. Now the main thing is to get rid of glass fragments – enemy number one of compost. Obviously, fertilizer containing glass fragments cannot be introduced into soil. However, if they are reduced to the size of grains of sand and rolled smooth, they can no longer harm the roots of future plants.
To this end, all the material sifted through the giant sieves goes into a vertical shaft in which it gets into an upward air current. The light particles – mostly organic – are carried off. The particles of glass and ceramics which are left go to the grinding zone.
The ballast which fails to pass through the sieve - rubber, plastics and wood fragments had to be taken back to the garbage dumps, and this type of refuse accounts for almost a quarter of all domestic waste. Now even this ballast is processed – by pyrolisis, or the thermal disintegration of complex substances into simpler ones. As a result valuable products are obtained, such as fuel gas, bituminous resins and solid carbonaceous compounds, which in our day find broad application as graphite substitute in metallurgy.
The plant’s final and main product is compost. It looks like ordinary earth. In fact, it is a biologically active substance which can be used far more effectively than an ordinary fertilizer. Due to a high temperature it is possible to employ it as a biological fuel to heat the soil in hot-houses. The compost’s biological energy is sufficient to grow two crops. After that, it can be transformed to open ground as an ordinary fertilizer.
The Leningrad plant was the Soviet Union’s first enterprise which almost wholly restores to the national economy what is contained in city dumps. Not only does it pollute the environment in any way, it does not even consume water on its technological requirements.
Ex.7 Translate the questions and find the answers on them:
1. Чому проблема міських сміттєвих сховищ набуває в наші дні глобальне значення?
2. Про які основні стадії переробки міського сміття ви взнали з тексту?
3. Які цінні матеріали можуть бути отримані в результаті переробки міського сміття?
4. Що є кінцевим продуктом промислової переробки міського сміття?
Ex.8 Make up the dialogue using the translated questions and the information from the text.
Ex.9 Remember the rules and fulfill some exercises.
Sequence of Tenses
(Узгодження часів в додаткових підрядних реченнях.)
1.Якщо дієслово головного речення виражено одним з теперішніх часів, то в додатковому підрядному реченні вживається відповідний час за змістом:
I know that she is busy now.
Я знаю, що вона занята зараз.
I know that she was busy yesterday.
Я знаю, що вона була занята вчора.
I know that she will be busy tomorrow.
Я знаю, що вона буде занята завтра.
2.Якщо дієслово в головного речення виражено одним з минулих часів, то дієслово підрядного речення повинно стояти в одному з минулих часів. При цьому додержуються наступні правила:
а) якщо дія в підрядному реченні одночасна з дією головного, то дієслово підрядного ставиться в формі схожої з Past Indefinite або в Past Continuous. Але на українську мову дієслово підрядного перекладається теперішнім часом.
Я знала, що вона багато працює.
I knew that she worked hard.
Я знала що вона працює над цікавою проблемою.
I knew that she was working at some interesting problem.
б) якщо дія підрядного речення передує дії головного, то дієслово підрядного треба вживати у Past Perfect. На українську підрядне перекладається минулим часом.
She said that she had worked at the factory some years before.
Вона казала, що працювала на фабриці декілька років тому.
в) якщо дія підрядного речення є майбутньою по відношенню до головного, в підрядному дієслово вживається у Future-in-the-Past, яке утворюється за допомогою should/would та інфінітива дієслова без частки to.
I knew that she would work this Sunday.
Я знала, що вона буде працювати цієї неділі.
Indirect speech ( Непряма мова)
При змінюванні прямої мову в непряму треба додержуватися правил узгодження часів, причому відповідно до змісту необхідно замінювати особові та присвійні займенники, а також і вирази,які вказують на час або місце дії.
Direct into Indirect:
Today – that day; yesterday – the day before ; tomorrow – the next day; ...ago - ...before; this.. – that..; these... – those...; here – there; last year – the year before; last month – the month before; last... – the... before; next... – the following
Якщо після дієслова to say є додаток, то в непрямій мові це дієслово замінюється на to tell.
She said to me, “ I have seen a good film this week”.
She told me that she had seen a good film tat week.
Indirect question and orders
( непряме питання та наказ)
Необхідно пам’ятати, що порядок слів у непрямому питанні такий же як в стверджувальному реченні.
- загальне питання з’єднується сполучниками if або whether, які відповідають частці чи.
My friend said to me, “ Will you go to the skating-rink on Sunday?” –
My friend asked me if (whether) I should go to the skating-rink on Sunday.
I asked him, “ Do you skate well?” –
I asked him if(whether) he skated well.
Якщо відповідь на загальне питання стверджувальна, то говорять:
I answered in the affirmative.
Я відповів стверджувально.
Якщо відповідь заперечна, то говорять:
I answered in the negative.
Я відповів заперечно.
- Спеціальне питання в непрямій мові поєднується питальним займенником:
She asked me,” Where will you go today?” –
She asked me where I should go that day.
- наказ в непрямій мові відповідає структурі наказу в прямій мові.
The teacher said to me, “ Go to the blackboard!”
The teacher told me to go to the blackboard.
Заперечна форма наказу або прохання утворюється з часткою not та інфінітиву дієслова з часткою to.
She said to me,” Don’t tell my mother about it.”
She acked me not to tell her mother about that.
The Infinitive (Інфінітив)
Інфінітив має наступні форми:
Voice
|
Indefinite
|
Continuous
|
Perfect
|
Perfect continuous
|
Active
|
To ask
|
To be asking
|
To have asked
|
To have been asking
|
Passive
|
To be asked
|
-
|
To have been asked
|
-
|
Indefinite – одночасна дія з дією присудка.
I am ready to help you.
Continuous – дія в процесі її розвитку та одночасна з дією присудка.
The children must be sleeping now.
Perfect- дія, яка передує дії присудка.
I am story to have told him the sad news.
Функції
- підмета:
To listen to him is always pleasant. – Слухати його завжди приємно.
- називної частини складного присудка:
To talk too much is to waste time. – Говорити дуже багато значить губити час.
- частини складеного дієслівного присудка:
May I come in? – Можна мені війти?
She is to help you in your work.- Вона повинна вам допомогти в вашій роботі.
- додатка:
Ann learned to speak English well. – Аня навчилася добре розмовляти англійською.
- частини складного додатка:
Do you expect him to come today? – Ви вважаєте, що він прийде сьогодні?
- означення:
Yuri Gagarin was the first man to fly into space. – Юрій Гагарін був першою людиною, яка полетіла в космос.
Ex.10 Open the brackets using the corresponding tense of the verb:
1. I knew they (to wait) for me at the metro station and I decided to hurry. 2. I didn’t know that you already (to wind) up the clock. 3. I was afraid that the little girl (not to be) able to unlock the front door and ( to go ) upstairs to help her .4. He says that he (to know) the laws of the country. 5. Sarie understood why Lanny ( not to come) the previous evening. 6. She asked me whether I (to remember) the legend about a faithful lion. 7. He understood that the soldiers (to arrest) him. 8. He could not understand why people ( not to want ) to take water from that well. 9. I suppose they (to send) a dog after the burglar immediately. 10. He said he ( to leave) tomorrow morning. 11. She says she already (to find) the book. 12. He stopped and listened: the clock ( to strike0 five. 13. She said she (can) not tell me the right time, her watch ( to be ) wrong. 14. I asked my neighbour if he ever ( to travel) by air before. 15. The policeman asked George where he ( to run) so early. 16. The delegates were told that the guide just ( to go ) out and ( to be ) back in ten minutes.
Ex.11 Translate into English using the rules of the sequence of tenses:
1. Я боявся, що заблукаю у лісі. 2. Вона знала, що ми ніколи не бачили її картини. 3. вчений був упевнений, що знайде розв’язання проблеми.4. Я знав, що ти приїхав у Київ, і сподівався, що ти відвідаєш мене. 5. Ми не думали, що він так розсердиться. 6. Ми вчора довідалися , що вона хвора. 7. Він думав що вона не прийде в технікум.8. Я знав, що моя сестра вивчає французьку, і думав, що вона поїде в Париж. 9. Мені сказали, що ти мені телефонував. 10. Я думав, що ти в Москві.11. Я не знав, що ти вже повернувся в Київ. 12. Ми сподівалися, що поїдемо в Лондон. 13. Вчитель сказав, що наші друзі надіслали лист із Лондона.14. Вона сказала, що її подруга запросила її в театр.15. Ми боялися, що не купимо квиток у театр. 16. Ми побачили, що діти граються у піску. 17. Вона сказала, що більше не буде купатися, тому що вода холодна. 18 Моя двоюрідна сестра сказала, що любить оперу і буде рада піти з нами в театр, хоча вже двічі слухала „ Травіату.( La Traviata)”.
Ex.12 Change the following sentences from Direct into Indirect Speech:
a) 1. Jack wrote to his friend: “I am not able to come to see you this summer”. 2. He said: “Our boat carries an oxygen reserve that will be enough for more that a week”. 3. The worker said: “I have brought all essential equipment”. 4. Ann said: “ I went on an excursion last week”.5. He said: “I have read this novel and like it very much”.
b) 1. She asked me: “Will you go to the theatre on Sunday?” 2. I asked her: “Did you finish this book yesterday? 3. Pete asked his mother: “May I go out?”4. The mother asked him: “Have you done your homework?» Pete answered: “Yes, I have”.
c) 1. Mary said to me: “Why didn’t you come?” 2. Mother asked me: “When did Tom go to bed?” 3. They asked Mary: “When will your husband return home?”4. The teacher asked me: “What is your name?”5. He asked Pete: “Where were you born?”
d) 1. He said to me: “Go this way, please”.2. The man said tome: “Give me a match, please”. 3. The teacher said to us “Open your books on page 11 and read the text”.4. She said to the child: “Don’t touch my books”.
Непряма мова: При перетворенні прямої мови на непряму не забувайте замінити обставини часу, як нижче зазначено.
Direct into Indirect:
Today – that day; yesterday – the day before ; tomorrow – the next day; ...ago - ...before; this.. – that..; these... – those...; here – there; last year – the year before; last month – the month before; last... – the... before; next... – the following
Ex.13 State the forms functions of the Infinitive. Translate the sentences:
1. To flow through an electric field electrons must be freed from their atoms. 2. The most important fact to remember about a diode is how much current it will pass with a given amount of plate voltage. 3. Another use for a diode is to maintain a special voltage level for a signal. 4. A diode circuit used to pass one half of a signal is a detector. 5. You will learn how to use a tube manual to obtain information about vacuum tubes. 6. The tetrode was developed in order to overcome a particular shortcoming of triodes. 7. The two charges are concentrated immediately adjacent to the junction and produce a potential barrier is such as to oppose the further diffusion of majority charge carriers across the junction, but to aid the movement of minority charge carriers.8. This current increases with in crease in the reverse bias voltage until the point is reached where almost no majority charge carriers possess sufficient energy to be able to cross the junction. 9. Holes are caused to drift towards the junction.
Самостійна робота №16
Теорія: Герундій. Дієприкметник. Віддієслівний іменник.
Текст:”Era of new technologies’
Ex.1 Read and define the meaning of the following words:
sphere n , ordinary a, special a, synthesize v, demonstrate v, mobilize v, test n, generate v, automatic a, utilization n, container n, resist v, packet n, infect v, activize v, accelerate v.
Ex.2 Read and remember the following words:
endeavor – спроба,зусилля
agency – засіб
confine – обмежувати
derive – відбуватися
devise – придумувати, робити винахід
defy – не піддаватися
associate – співробітник
surface – з’являтися на поверхні
search – шукати
buoy – буй, бакен
lattice – решітка
clutter – загромаджувати
evolve – розробляти, розвивати
hover – знаходитися поблизу, парити
Ex.3 Give the correspondence:
A: animal protein, vegetable protein, wood wastes, artificial media, feed additive, full-valued food, all-powerful bacteria, modern technical means, underground explosion, biochemical energy sources, biochemical cells, sonar system, waste utilization, used containers;
B: повноцінна їжа, всесильні бактерії, твариний білок, сучасні технічні засоби, рослиний білок, підземний вибух, поживний додаток, деревинні відходи, штучна середа, використання відходів, система звукової локації, використання ємності, біохімічні електроелементи, біохімічні джерела енергії.
Ex.4 Check your knowledge the following words with of the terminological dictionary:
nutrient, harvest, farming, bed, spark, cell, clog, stench, convert, film, culture, community, feeding.
Ex.5 Read the text, translate it and give the main idea in two-three sentences:
Era of new technologies
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