Page 914 - Basic Electrical Engineering

• Salal, Jammu & Kashmir 6 × 115 690

• Sardar Soravar, Gujrat 6 × 200; 5 × 1406 × 200; 5 × 140 1450

• Nagarjun Sagar, Andhra Pradesh 1 × 110; 7 × 100.8; 5 × 30 965

• Idukki, Kerala 6 × 130 780

However, there are certain demerits of hydroelectric plants like heavy

investment required for the construction of dam, etc.; time taken to instal a
plant is high; opposition from environmentalists and the people living on the

land to be used as a reservoir; cannot be constructed anywhere, i.e., near the
load centre, etc.
The first hydroelectric power plant was installed in USA in the year 1882

followed by Sweeden and Japan. In India, the first hydroelectric power plant
was installed in 1897 in Darjeeling area in West Bengal.

A few hydroelectric power plants in India are mentioned in Table 13.1.

13.6 NUCLEAR POWER-GENERATING STATIONS

We have known that in a thermal power plant, the heat required to produce
steam is obtained by burning coal, oil, or natural gas.
In a nuclear power plant the required heat is produced by a process called

fission of uranium atoms. Fission or splitting of uranium atoms takes place in
a nuclear reactor. Uranium is therefore called nuclear fuel. Nuclear fuel

consists of two types of uranium, namely U=238 and U=235. U=235 splits
easily, i.e., its nucleus, which is composed of protons and neutrons, break up

and release heat as well as neutrons. This splitting of atoms is a chain
reaction. Fission in U=235 is started by bombarding it with neutrons. In the

fission reaction, neutrons are released and heat is generated. When neutrons
hit other uranium atoms, these atoms also split releasing neutrons as well as
heat. These neutrons strike other atoms of uranium. Thus, one fission

(splitting of uranium atom) leads to more fission, and hence creates a chain
reaction. This makes the fission self-sustaining once the process is started.

This chain fission reaction once started will become an uncontrolled one
unless some control mechanism is used. In a nuclear reactor, fission reaction