Focused Practice

I. Answer the following questions:

1. What do you need to build a nuclear reactor?

2. How are the pellets arranged?

3. What is water inside a pressure vessel used for?

4. Why are control rods inserted into the bundle?

5. How does the uranium bundle act?

6. What acts as a radiation shield?

7. What are the secondary containment structures necessary for?

II. Analyse the grammar structures underlined in the above text.

III. Speak on: Building a nuclear reactor.

Unit 42 Grammar: Non-finite Forms of the Verb. The Infinitive Constructions. The Passive Voice Word List:

1. ocean energy sources	источники энергии океана
2. tidal	приливно-отливный
3. ocean thermal energy conversion	преобразование тепловой энергии океана в электричество
4. water column	водяной столб, водомерная колонка
5. chamber	камера
6. funnel	загрузочная воронка
7. counter-rotating	вращение в противоположном направлении
8. to suck	всасывать
9. regardless of	независимо от
10. to exploit	разрабатывать
11. temperature gradient	перепад температур
12. temperature differential	разность температур
13. the working fluid	рабочая среда, рабочее тело
14. open-cycle	разомкнутый цикл
15. closed- cycle	замкнутый цикл
16. desalinated	опресненный
17. flash	мгновенно
18. loop	контур
19. vaporizer	испаритель

Big Plans for Ocean Power Hinge on Funding and Additional r&d

There are three ocean energy sources:

1) Wave. 2) Tidal. 3) Ocean thermal energy conversion (OTEC).

Where the shoreline has suitable topography, a cliff-mounted oscillating water column can be used. With oscillating water columns the incoming waves cause the water level in the main chamber to rise. As the water level rises, it forces air up a funnel that drives a “Wells” counter-rotating turbine. When the wave falls the air is sucked back down into the turbine. The Wells turbine is designed to turn in the same direction regardless of the air’s flow.

OTEC exploits the temperature gradient at various depths of the ocean. In essence, OTEC converts solar radiation into electricity. For OTEC to produce significant amounts of electricity, a temperature differential of at least 36 F is required. There are three types of OTEC systems: open–cycle, closed–cycle and hybrid–cycle.

In the open–cycle system, the warmer seawater closer to the surface, which is the working fluid, is evaporated in a vacuum chamber to produce steam. This steam is then expanded through a low–pressure turbine generator to produce electricity. After leaving the turbine the steam is condensed in a condenser to produce desalinated water. Cold seawater from lower ocean depths is used in the condenser. A new supply of warmer seawater is used in the next cycle.

With a closed–cycle system, a low boiling liquid is used as the working fluid. The warm seawater vaporizes the working fluid, which is used to drive an electric turbine generator. Using cold seawater, the vapor is condensed back into a liquid to start the cycle all over again.

The hybrid system is a combination of the open and closed–systems. In a hybrid system, warm seawater enters a vacuum chamber where it is flash evaporated into steam. This is similar to the open–cycle evaporation process. The steam is used to vaporize the working fluid of the closed–cycle loop on the other side of an ammonia vaporizer. From here the vaporized working fluid drives a turbine to produce electricity.