The Fission Chain Reaction

Date: 2015-10-07; view: 433.

The First Nuclear Power Station in the World

1. The first electric power station working on nuclear fuel was built in the USSR in Obninsk by а team of scientists and engineers under the guidance of Igor Kurchatov in 1954.

2. The main purpose of the first NPS was to make sure of technical feasibility of converting nuclear energy into electrical one.

3. The reactor of the station was а uranium-graphite reactor of the channel type, water cooled.

4. The reactor core had the shape of а cylinder 150 cm high and 70 cm in diameter. It housed 128 fuel rods and 22 control rods, four of them were used for emergency cases.

5. The moderator was graphite in the form of а triangular lattice.

6. The double-circuit system produced superheated steam at the temperature of 280°С and the pressure of 12 atm. for а conventional turbine.

7. Heat capacity of the reactor was 30 MWt.

8. Four circulating pumps of centrifugal type circulated coolant through the primary circuit to four steam generators.

9. The biological shielding of the reactor was а layer of water one meter thick and а concrete wall 3 meters thick.

1. As secondary neutrons split other nuclei the number of fissions increases.

2. The fission chain reaction is established if at least one secondary neutron is produced in each fission.

3. The number of neutrons in one fission is called a generation.

4. The ratio of the number of neutrons in one generation to the number of neutrons in the preceding generation is called the multiplication factor.

5. Chain reaction can be self-sustaining if the multiplication factor is not less than unity.

6. To develop a fission chain reaction we can increase the U235 content in uranium or can slow down neutrons.

7. In the first case both fast and slow neutrons can maintain the chain reaction.

8. In the second case the chain reaction is induced mostly by slow neutrons.

9. Controllable chain reaction is used in nuclear reactors to produce energy.

10. Uncontrollable chain reaction results in explosion and is used in atomic bombs.