Hydroelectric Power Plants

COMPREHENSION

Number 1

NEW SOURCES OF ENERGY

Specialists consider hydrogen a very promising energy source. It can be used as fuel in transport, industry and the home. Scientists have found many ways of producing hydrogen — basically from water. And it can also be obtained from coal.

The gas of hydrogen is easy to transport and store. Use of hydrogen as an energy source will help keep the environment clean. Besides, if hydrogen is used as motor-car fuel, there is no danger of any explosions in case of an accident on the road.

The experiment was conducted with the сars which run on liquid hydrogen fuel.

There is also tidal power to produce hydroelectricity by harness­ing the ebb and flow of the tides. The first power plant was built in 1961-67 in Brittany, a region in North-Western France on a peninsula between the English Channel and the Bay of Biscay. This power plant produced 240 MW power.

The energy of the Sun is an unlimited energy source. Solar batteries are known to be used for heating and lighting houses, for driving space ship equipment. Today solar batteries are used in new experimental motor-car designs.

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no danger of any explosion in case of an accident — нет опасности взрыва в случае (дорожного происшествия).

COMPREHENSION

Number 2

Radiation Energy

Although many nuclides are stable, most are not. Stability is determined mainly by the balance between the number of neutrons and protons a nuclide contains. Nuclei with too many neutrons tend to transform themselves to a more stable structure by converting a neutron to a proton, nuclei with too many protons convert the protons to neutrons. The spontaneous transformation of a nucleus is called radioactivity, and the excess energy emitted is a form of (ionizing) radiation.

The energy of the various types of radiation – alpha and beta particles and gamma rays – is usually expressed in the unit of electron volt, symbol eV. Multiples of this unit are often used, such as million or 106 electron volts, symbol MeV. For instance, the energy of alpha particles emitted by polonium-214 is about 7.7 MeV. Beta particles from lead-214, also formed in the uranium-238 decay series, have a maximum energy of 1.0 MeV. During the past few decades, several hundred radioactive isotopes (radioisotopes) of natural elements have been produced artificially including, for example, strontium-90, caesium-137 and iodine-131. Several new radioactive elements have also been produced in quantity, for instance promethium and plutonium, although the latter does occur naturally in trace amounts in uranium ores.

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artificial(ly) -

COMPREHENSION

Number 3

Nuclear reactors

Nuclear reactors depend on a reaction between neutrons and the atomic nuclei of the fuel for their operation. Uranium, the fuel for almost all reactors, consists princi­pally of two isotopes, uranium-235 and

uranium-238.

Energy is released when uranium-235 nucleus absorbs a neutron and undergoes fission, that is, splits into two large energetic fragmentsor fissionproducts, accompanied by the release of fast neutrons and some gamma radiation.

The neutrons are usually slowed in the reactor so that they induce further fissions in the uranium-235. Such neutrons are often called thermal (slow) neutrons and the reactors that employ them - thermal reactors.

The fuel in a nuclear reactor is assembled in an array called the core, which also contains the moderator a material, generally water or graphite, that slows the fast neutrons.

A coolant, usually water or gas, conducts heat away from the fuel and then passes through heat exchangers to make steam. The steam then drives turbine generators to make electricity.

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to induce -

COMPREHENSION

Number 4

Hydroelectric Power Plants

Hydroelectric power plants are built on rivers. Large-capacity hydroelectric power plants are commonly located at considerable distances from the consumers of electric power.

The production process at these plants is rather simple: the water flows into the hydroturbine, acts upon the runner blades and rotates the runner and the turbine shaft.

The generator shaft is connected to the turbine runner shaft. The difference in the water level influences the power capacity of a plant, i.e. the magnitude of the water head and the daily inflow of water fluctuates considerably according to the season.

The production process is different at power plants of different constructions and of different kinds. In nuclear power plants, for example, it is not so simple as in hydroelectric power plants. The nuclear power plant generates electricity by obtaining heat energy from fission chain reaction. The conventional power plants burn fossil fuels ( )for producing electrical power. As for hydroelectric power plants they use the power of falling water.

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runner - ротор

blade - лопасть

shaft - привод, вал

fluctuate - колебаться

COMPREHENSION

Number 5

COMPREHENSION

Number 6

COMPREHENSION

Number 7

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