1. Pressurized Water Reactors
2. Chernobyl Accident
3. RBMK Reactor
4. Reactor Control
5. South-Ukrainian NPP
6. Zaporizzhya NPP
7. Nuclear Reactor Arrangement
8. First Nuclear Power Station
9. Types of Nuclear Power Plants
10. NPP Nuclear Safety
11. Fission Chain Reaction
12. The Arrangement of a NPP
13. Research Training Reactor IR-100
14. Reactor Classification
15. Boiling-Water Reactor
1. A pressurized-water reactor is that in which the coolant is under high pressure.
2. It uses uranium fuel enriched with U-235.
3. A constant flow of water passes through the core of this reactor.
4. A high pressure prevents the water from boiling at high temperatures.
5. The water flows through the heat exchanger and back to the reactor in a closed system of pipes.
6. In the heat exchanger heat is transferred to a low-pressure water of the secondary system.
7. This water is converted into low-pressure steam.
8. This steam drives a turbine that turns an electric generator.
9. The ease of operation is the main advantage of PWR.
10. The disadvantage of PWR is that most of them produce wet steam which causes erosion.
1. Chernobyl accident took place at Chernobyl NPP on April 26, 1986 at 01:23 a.m.
2. Chernobyl power plant is located near Pripyat, Ukraine.
3. The station consisted of four reactors of RBMK-1000 type, each capable of producing 1 gigawatt (GW) of electric power
4. The four units together produced about 10% of Ukraine’s electricity at the time of the accident.
5. The construction of the plant began in 1970s, with reactor No.1 commissioned in 1977 followed by No.2 (1978), No.3 (1981) and No.4 (1983).
6. During the daytime of April 25, 1986, reactor 4 was scheduled to be shut down for maintenance.
7. The aim of the test was to determine whether the turbines in the rundown phase could power the pumps while the generators were starting up.
8. At 1:23 a.m. steam to the turbine was shut off.
9. The turbine was disconnected from the reactor increasing the level of steam in the reactor core.
10. The reactor operation became progressively less stable and more dangerous.
11. The reactor jumped to around 30 GW, ten times the normal operational output.
12. An explosion at the plant was followed by radioactive contamination of the surrounding geographic area.
1. The RBMK channel-type uranium-graphite reactor operates as a single-loop system.
2. The steam produces in the core is directly fed to the turbine.
3. The reactor is located in a concrete well.
4. It is made of vertical graphite columns with central holes to house process channels and special channels.
5. Process channels house fuel elements and provide coolant flow.
6. Special channels house control and safety rods and also means of technological control system.
7. The core contains fuel cassettes.
8. Each cassette contains two fuel assemblies, each assembly consisting of 18 fuel elements.
9. Fuel elements are formed of fuel pellets enclosed in hermetical zirconium cans.
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.
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.
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.