A list of active words and expressions

fission chain reaction	– цепная реакция деления
fissile	– делящийся
coolant	– теплоноситель
rod	– стержень
core	– активная зона реактора
moderator	– замедлитель
rate	– скорость
arrangement	– устройство
shield	– защита
to remove	– отводить, удалять
to confine	– удерживать
to drive (drove, driven)	– приводить в движение

Ex. 1. Fill in the blanks

1. A nuclear reactor is a … where a fission … reaction produces heat energy … generating electricity. 2. The mechanical energy of … drives the turbines. 3. The fuel rods … a fission chain reaction. 4. The coolant is used to ... heat from the core. 5. The moderator is needed to ... fast neutrons. 6. Control ... are used to control the … of the chain reaction. 7. The shield is used to ... radiation. 8. There is a great ... of nuclear reactors. 9. All nuclear reactors … in fuel, power level and purpose. 10. The nuclear reactors use such ... materials as U-233, U-235 and P-239.

Ex. 2. Translate from Russian into English.

1. производить пар

2. механическая (тепловая) энергия

3. большое разнообразие

4. уровень мощности

5. отводить тепло

6. удалять радиоактивные продукты распада

7. сдерживать (препятствовать выходу) радиацию

8. замедлять быстрые нейтроны

9. регулировать скорость цепной реакции

10. время от времени

Ex. 3. Learn the dialogues.

1. – What do you know about a nuclear reactor?

– Well, I know that it is a device which produces a fission chain reaction for generating electricity.

– What fuel does it use?

– It uses mostly uranium.

– What components does reactor consist of?

– It consists of five basic components: the core, the coolant, control rods, the shield and the moderator, which is used only in thermal reactors.

2. – What materials can be used as fuel in a nuclear reactor?

– There are three fissile materials that can be used in a reactor: U-233, U-235, and Pu-239.

– And which of them is preferable?

– U-235. It can be used both in naturally-occurring form in a mixture with U-238 and in an enriched form.

3. – Why is the coolant necessary in a reactor?

– It is used to take away heat to prevent core-melting.

– What are the requirements for the coolant?

– They are obvious: it should not capture neutrons and must have a high boiling point.

4. – What is the purpose of control rods?

– Their purpose can be clearly seen in their name: they control the rate of the chain reaction.

– But how is this control achieved?

– Well, for one thing the rods are made of neutron-absorbing materials and, secondly, they are automatically pushed in or pulled out whenever the rate of neutron production exceeds or drops below a certain level.

Ex. 4. Answer the following questions.

1. What is a nuclear reactor?

1. What does the fission chain reaction produce?

1. In what way does the nuclear reactor generate electricity?

1. What does the nuclear reactor consist of?

2. What is the moderator used for?

1. What kind of fuel does a nuclear reactor use?

Ex. 5. Speak about the reactor requirements.

UNIT VII

TEXT Reactor Types

There are two principal categories of nuclear reactors. They are divided into thermal reactors which employ thermal neutrons, and fast neutron reactors which employ fast neutrons.

As for the thermal reactors, they have a moderator to slow down fast neutrons. It may be ordinary water, carbon or heavy water.

There are some predominant types of thermal reactors. They are a boiling-water reactor, a pressurised-water reactor, CANDU, a high-temperature gas-cooled reactor and a water-cooled graphite moderated channel type reactor. The thermal reactors use U-235 as the fuel and a moderator to slow down fast neutrons.

The fertile raw materials for breeder reactors are Th-232 and U-238. There are two breeder systems: thermal breeder reactors which use slow neutrons and Th-232 as the fuel, and fast breeders which use fast neutrons and U-238 as the fuel. The fast breeder reactors convert U-238 into Pu-239. They have some advantages over the thermal reactors.

The fast breeder reactors can produce more fuel than they consume it. They make full use of the fuel and non-productive absorption of neutrons is less in them.

The general trend in the future development of nuclear power is towards the construction of the fast breeder reactors.