FISSION AND THE FIRST REACTORS - раздел Иностранные языки, THE PRE_ATOMIC AGE
Fission Of Uranium Was Discovered—Or, More Precisely, Recogni...
Fission of uranium was discovered—or, more precisely, recognized for what it was—in 1938. Scientists quickly recognized that large amounts of energy are released in fission and that there was now, in principle, a path to a chain reaction. By early 1939, it was verified that neutrons are emitted in fission, and it soon became apparent that enough neutrons were emitted to sustain a chain reaction in a properly arranged “pile” of uranium and graphite.It took several more years to demonstrate the practicality of achieving a chain reaction. This work was led by Fermi, who had left Italy for the United States, and it culminated in the development and demonstration of the first operating nuclear reactor on December 2, 1942 at an improvised facility in Chicago.
The discovery and preliminary understanding of fission came at a time when the prospect of war was much on people’s minds. The start of World War II in Europe in August 1939 ensured that military, rather than civilian, applications of atomic energy would take primacy, and the early work was heavily focused on the military side, in both thinking and accomplishments. A major goal of the nuclear program was the production of plutonium-239 (239Pu), which was recognized to be an effective material for a fission bomb. The 239Pu was to be produced in a reactor, by neutron capture on uranium-238 (238U) and subsequent radioactive decays.
The first reactor in Chicago was very small, running with a total power output of 200 W. However, even before the successful demonstration of a chain reaction in this reactor, plans had started for the construction of the much larger reactors required to produce the desired amounts of plutonium. A pilot plant, designed to produce 1 MW, was completed and put into operation at Oak Ridge, Tennessee in November 1943. A full-size 200-MW reactor began operating at the Hanford Reservation in Washington state in September 1944—a millionfold increase in power output in less than 2 years.
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FISSION AND THE FIRST REACTORS
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Pre-reading tasks
1. The text you are to read is headlined “The Pre-atomic Age”. In your opinion, what can it run about?
2. Think of and write down 4-5 questions the answers to which you expect
THE PRE-ATOMIC AGE
Ancient Greek philosophers were the first known scientists to suggest that matter was made up of small, unseen elements, a theory described as “atomism” by Democritus of Abdera in the 5th century В
Comprehension check
1. Choose the best ending a, b, or c to complete the sentences.
1. Ancient Greek philosophers
a) were the first to suppose that matter was composed of small
Vocabulary work
1. The words given in A are used in the text above. Find their synonyms in B.
A
B
to suggest
Pre-reading tasks
1. Have you ever heard about John Dalton, Heinrich Geissler, William Crookes?
2. Can you recollect what they are famous for? What contributions to science did they make?
Comprehension check
1. Consult the text above and complete the following sentences.
1. Atomism reentered scientific ... in the 19th century.
2. Dalto
Pre-reading tasks
1. Do you know:
a) the names of Henri Becquerel and Pierre and Marie Curie? What are they famous?
b) when the Curies and Becquerel worked?
c) what
HENRI BECQUEREL AND THE CURIES’ DISCOVERIES
X-rays were only the first, surprise of the 1890s. New rays were soon detected which proved to be even more profoundly alien to known science.
The French p
Comprehension check
1. Match the discoveries and inventions with the names of scientists.
Marie Curie
found out that uranium salt emitted pen
Vocabulary work
1. There are some words given in bold type in the text. Choose their synonyms in the box below.
to emit
to discover
Pre-reading tasks
1. The text you are going to read is headlined “Further advances in the field of radioactivity”. In your opinion,
- what does it run about?
- what
FURTHER ADVANCES IN THE FIELD OF RADIOACTIVITY
Their work, which led to the Nobel Prize for both (and two prizes for Marie, a rare honor), confirmed the cathode-ray research of British scientist J. J.Thomson, who had experimente
RADIOACTIVITY AND RADIOACTIVE EXPOSURES
Radioactivity and the associated radiation exposures are sometimes thought of as environmental problems that have been created by modern science and technology. However, substantial
Pre-reading tasks
1. If you were asked to make a report on the theme “From nuclear reactions to nuclear fission” which events would you include in it and what scientists would you mention? Comment
FROM NUCLEAR REACTIONS TO NUCLEAR FISSION
In 1913, Neils Bohr, a brilliant Danish physicist and a post-doctoral student of Rutherford’s, elaborated and modified Rutherford’s model by incorporating quantum mechanical (the study of mechanica
Comprehension check
1. Some dates, namely years are mentioned in the text. Match them with the events described.
J. Chadwick discovered the
Vocabulary work
1. The words given in two columns of the box are mentioned in the text and they have similar meanings. Find and name these pairs.
A
Pre-reading tasks
1. The paragraphs of the text given below are jumbled. Arrange them in the logical order. Comment on your choice of paragraphs succession.
2. You are sure to know the name of a f
SPECULATIONS BEFORE THE DISCOVERY OF FUSION
Atomic energy, now usually called nuclear energy, became a gleam in the eye of scientists in the early part of the 20th century. The possibility that the atom held a vast
Pre-reading tasks
1. Otto Hahn, Lise Meitner, Fritz Strassman made several key breakthroughs revealing secrets of nuclear fission. Can you give any information about these scientists? If nothing is known to you,
REVEALING SECRETS OF NUCLEAR FISSION
Enrico Fermi and his colleagues missed a reaction in the uranium which would later be determined to be the first example of nuclear fission. The task, therefore, fell tо scientist Otto Hahn, who wa
Comprehension check
1. Match the names of scientists with the information about them. (Sometimes information refers to more than one scientist).
Otto Hahn
co
Vocabulary work
1. Find synonyms or antonyms among the words given in italics in the text and name them. Be careful as the verbs are used in different forms
2. Fill in the tab
Follow-up activities
1. In pairs, discuss the information given in the text.
2. Make up a short report based on the text. (Presenting only key ideas).
3. Find some add
Pre-reading tasks
1.In the text below the names of Henri Becquerel, Pierre and Marie Curie, Ernest Rutherford are mentioned. Recollect what each of them is famous for. The table below will help you to fulfill the
RADIOACTIVE MATERIALS AS SOURCES OF NUCLEAR ENERGY
Radioactive … involves the spontaneous disintegration of an atomic nucleus. As the nucleus …, various particles as well as high-energy electromagnetic waves are … . Ra
Pre-reading tasks
1. The text you are to read is headlined “Boiling water reactors”. In your opinion, what problems are discussed in this text?
2. If you were to make a report on this theme wha
BOILING WATER REACTORS
Consider the simplified schematic of one of the most common types of nuclear reactor, a boiling water reactor. (See the accompanying illustration.) Boiling water reactors were firs
GLOBAL WARMING AND NUCLEAR POWER
The idea behind global warming is simple enough. Earth’s atmosphere retains some of the heat that Earth receives from the Sun. The amount of heat retained depends upon the chemical composition of t
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