Reactor Control

1. Operation of reactors is based on the process of fission chain reaction of U-235.

1. Stable reactor operation depends on the multiplication factor k.

2. If k=1, the reactor is in its critical state and can operate under stationary conditions.

3. If k>1, the reactor is in the subcritical state and so the chain reaction is damped.

4. With k>1 the chain reaction is accelerated.

5. k deviation is characterized by reactivity p.

6. For reactor stationary operation it is necessary to keep reactivity on the p=0 level.

7. This may be achieved through the system of absorber rods.

8. When the control rods are inserted into the core, the neutron absorption increases.

9. When they are moved up, the neutron flux increases.

10. When the reactor is in the active state, the fuel gradually burns out.

11. When the reactivity is depleted, the reaction ceases, the rods are completely drawn up.

South-Ukrainian npp

1. The construction of SU NPP began in the spring of 1975.

2. The first power unit was launched into operation in December 1982.

3. At present, it is one of the largest power-generating enterprises in the South of Ukraine.

4. SU NPP operates three power units with а total capacity of 3000 MW.

5. The first two ones comprise a WWPR-1000 reactor.

6. The station’s thermal arrangement consists of two circuits.

7. The first circuit includes the reactor unit, four circulation loops, steam generators, and main circulating pumps.

8. The fuel core, structural elements guiding the coolant, and reactivity controls are in the reactor’s shell.

9. Highly enriched uranium dioxide is used as fuel.

10. The secondary (non-radioactive) circuit consists of four steam generators and а 1,000 MW turbine generator set.

11. The station’s control combines central panel monitoring, remote control facilities, and automatic regulation.

12. Power control and scram functions are performed by moving the neutron absorbers in and out of the core.

Zaporizzhya npp

1. The Zaporizzhya NPP is situated in the Zaporizzhya region in the Ukraine, not far from the operating Zaporizzhya thermal power station.

2. That power station was designed to supply power to the southern regions of the Ukraine.

3. The power station is planned to have six power units with а unit capacity of 1000 МW.

4. The construction of the Zaporizzhya NPP was commenced in 1979.

5. The electric power capacity of the ZNPP is 6000 МW.

6. The enclosure of the reactor building is divided into confined access and free access zones.

7. The free access zone houses the reliable auxiliary power supply system, control rooms, ventilation system, emergency feed pumps with storage tanks and steam generator safety valves.

8. The confined access zone houses the systems and equipment operating in contact with the radioactive water of the primary circuit.

9. The primary coolant circuit comprises the reactor and four circulation loops, each consisting of а main coolant pump, а steam generator and austenite-steel piping.

10. WWER-1000 reactor is а shell-type pressurized water one, water being used here as coolant and moderator.

11. The secondary coolant circuit is non-radioactive, consisting of steam-producing part of steam generators, а turbine and the auxiliaries of the turbine room.