Atomic Power for Rockets

The heart of a nuclear-rocket engine, of course, is the reactor that converts nuclear energy into heat.

The fuel of the reactor consists of a special kind of «isotope» of Uranium-235. When properly bombarded with neutrons the uranium nuclei break up or «fission» into a pair of fragments and emit more neutrons in the process, thus keeping the reactions going.

The fission process releases energy and the excess energy is carried away by the neutrons and by gamma rays. Since all of the fragments and most of the neutrons and gamma rays are stopped within the reactor, the energy that is released by U-235 fission will heat the reactor.

For making a nuclear-rocket engine thermally efficient the reactor’s temperature must be as high as possible. The melting point of uranium, 2,070 degrees F, sets a theoretical limit. Graphite, which withstands much higher temperatures, is a very good material for the reactor’s «moderator». So all present experimental reactors for nuclear-rocket engines are made of U-235 metal powder placed in graphite.

A cold gas, hydrogen, enters several hundred narrow passages drilled through the graphite - uranium reactor core and is heated almost to the white-hot operating temperature. On coming from the passages, the hot gas expands through a nozzle in which it attains supersonic speed. The exhaust speed of the nuclear-rocket engine can probably reach 23.000 to 30.000 feet per second, which is twice as much as from a rocket engine using chemical combustion of hydrogen and oxyden.

Вариант 3

1. Перепишите и письменно переведите на русский язык следующие предложения. Помните, что объектный и субъектный инфинитивные обороты соответствуют придаточным предложениям (см. образец выполнения 1)

We supposed them to have finished their work.

The two countries are expected to discuss measures to eliminate double taxation.

Television is said to have both advantages and disadvantages.

This is the subject to be discussed at the next meeting.

2. Перепишите и письменно переведите на русский язык следующие предложения. Обратите внимание на перевод зависимого и независимого (самостоятельного) причастных оборотов (см. образец выполнения 2).

The night being dark, the victim could not notice whether the robber was armed.

Mendeleyev discovered the Periodic law of elements, the table bearing his name.

Having refused to unload American ships the French dockers lost their job.

3. Перепишите и письменно переведите на русский язык следующие сложные предложения. Обратите внимание на перевод условных предложений (см. образец выполнения 3).

If he were at the Institute now, he would help us to translate the article.

He demanded that the car should be repaired by tomorrow.

If it had not been so cold, I should have gone to the country.

4. Прочитайте и устно переведите с 1-го по 5-й абзацы текста. Перепишите и письменно переведите 1, 2, 3, 4 абзацы текста.