Npp Nuclear Safety

1. Nuclear safety should prevent nuclear and radiation accidents and limit their consequences.

2. Nuclear safety strategy includes five layers of defense.

3. The first defense barrier in design is the inert ceramic quality of nuclear fuel.

4. The second layer of defense covers quality of fuel cladding.

5. The third layer of defense is determined with the reactor pressure vessel.

6. The fourth layer of defense includes resistance of the containment building.

7. The fifth layer of defense depends upon the reactor building or а second outer containment building.

8. Redundancy in engineering is the duplication of critical components of а system to increase reliability of the system.

9. An error in а control system may result in а failure of the whole plant.

10. Duplication or triplication of critical components of а system increases its reliability.

Fission Chain Reaction

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 at 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.

The Arrangement of a npp

1. A NPP converts heat into electricity.

2. Nuclear energy is usually used as a heat source.

3. Energy is given off by the nuclear fuel as nuclei of Uranium split into pieces.

4. This energy is in the form of fast-moving particles and invisible radiation.

5. As the particles and radiation move through the fuel and surrounding water, the energy is converted into heat.

6. The heat is used to heat water to the boiling point and produce steam.

7. This steam is carried by pipes to spin the turbine.

8. The turbine is connected to a generator.

9. When the turbine shaft spins, the generator turns and produces electricity.

10. This electricity is then carried by wires to the homes, enterprises and institutions which use the electricity.

Research Training Reactor ir-100

1. IR-100 is a research reactor used for training engineers for Ukrainian NPSs.

2. It is also employed for experiments and research work.

3. IR-100 is a water-cooled and water-moderated reactor with thermal output of 200 kWt.

4. Its core is a hexahedral prism filled with UO2 enriched with U235.

5. The enrichment of fresh fuel is 10 per cent.

6. The fuel assembly is made of 7 fuel rods.

7. The cooling system has two circuits, primary and secondary, and two heat exchangers.

8. The pressure in the secondary circuit is 2-3 times greater than in the primary one to prevent contamination in case of an integrity failure.

9. Experimental facilities are the heat tower, three horizontal channels, 8 vertical channels, one central experimental channel, the recoil box and pneumatic post.

10. IR-100 was put into operation in 1974.