It is interesting to note that a 210,000 kW heat power plant consumes more than 2,000 tons of coal daily, whereas an atomic - power plant of equal capacity takes only about 800 grammes of Uranium-235.

There are great possibilities for the use of radioactive radiation in different radiation-chemical processes. For instance, radiation polymerization of various organic compounds, which makes it possible to produce materials with new qualities.

Radioactive isotopes are of great importance today. Several thousand research medical, agricultural and industrial organizations of our country make use of radioactive isotopes.

Russian scientists do their best to make the atom serve peace and progress and further develop the peaceful uses of atomic energy.

Text 3. Nuclear power station

Atomic energy was first used for the explosion of the atomic bomb in 1945. Few people realized at first that the same energy which can destroy an entire city so easily can also be harnessed for the good of mankind.

The first practical realization of this came with the an­nouncement in 1954, that a power station working on atomic energy had been put into operation in the USSR. The effect of this was to make people realize that nuclear power was not something in the remote future but was quite possible, because the technical problems had been solved.

A nuclear power station is similar to ordinary power sta­tions with the one exception, namely, instead of a coal-burn­ing furnace it has a nuclear furnace, i.e., heat is produced by nuclear fission in a reactor.

As for the first in the world nuclear power station men­tioned above, the fuel is uranium enriched 5 per cent with U-235. The pile is graphite-moderated and water-cooled. It generates 5,000 kW.

The pile can be cooled by many means, namely, by gas, water or liquid metal. The heat is applied to produce steam which in its turn is used to generate electricity.

The pile is controlled by a "moderator" that is, rods of cadmium or boron steel which absorb neutrons readily and so stop the chain reaction when they are inserted into the pile.

The reactors being built at present, consist essentially of uranium bars which lie in a number of channels drilled through blocks of graphite. The purpose of graphite can be explained if we imagine the fission process starting in a bar of uranium somewhere at the centre of the pile. The first fission releases neutrons enough to carry on the process and establish the chain reaction but they are moving so fast that they escape out of the bar of uranium in which they were born without giving rise to any further fission. Outside the bar the neutrons find themselves surrounded on all sides by graphite. Graphite, like heavy water, is what is known as a “moderator”, that is to say, it possesses the power of making neutrons lose energy, without absorbing them; so that by the time the neutrons have reached the other side of the graphite and come into contact with another bar of uranium, they are of just the right energy to promote fission within the bar. The graphite is made exactly of the right thickness for this purpose.

In our country it is the practice to enclose a large-scale reactor in a steel shell. Thus, if an accident should occur to the pile, there is no possibility of radioactive leakage. A further shell of concrete, the so-called biological shield, lies outside the steel shell. The function of this biological shield is to absorb radiation escaping from the pile so that no one should be injured by approaching the pile.