Nuclear power plant Performed by Zhuk A.D.

Purpose of this presentation is to show importance and danger of nuclear power plant. My opinion: I think we need of nuclear power plant because now we can’t live without it. It’s electricity, worm, foods, computer and so on. But sometimes we are not carefully using this energy and if we want to generate energy from nuclear reactor we must protect the Earth of pollutant emission!

Contents 1 Introduction 2 History 3 Systems 3.1 Nuclear reactors 3.2 Steam turbine 3.3 Generator 3.4 Cooling system 3.5 Safety valves 3.6 Feed water pump 3.7 Emergency power supply 4 Human error 5 Future power plants Conclusion

1 Introduction A nuclear power plant is a thermal power station in which the heat source is a nuclear reactor. As is typical in all conventional thermal power stations the heat is used to generate steam which drives a steam turbine connected to a generator which produces electricity. As of 16 January 2013, the IAEA report there are 439 nuclear power reactors in operation operating in 31 countries.

2 History Electricity was generated by a nuclear reactor for the first time ever on December 20, 1951 at the EBR-I experimental station near Arco, Idaho in the United States. On June 27, 1954, the world's first nuclear power plant to generate electricity for a power grid started operations at Obninsk, USSR. The world's first commercial scale power station, Calder Hall in England opened on October 17, 1956.

Nuclear power plant at Obninsk, USSR.

3 Systems 3.1 Nuclear reactors A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction.

The nuclear reactor is the heart of the plant. In its central part, the reactor core's heat is generated by controlled nuclear fission. With this heat, a coolant is heated as it is pumped through the reactor and thereby removes the energy from the reactor. Heat from nuclear fission is used to raise steam, which runs through turbines, which in turn powers either ship's propellers or electrical generators.

3.2 Steam turbine The purpose of the steam turbine is to convert the heat contained in steam into mechanical energy. The engine house with the steam turbine is usually structurally separated from the main reactor building. It is so aligned to prevent debris from the destruction of a turbine in operation from flying towards the reactor.

3.3 Generator The generator converts kinetic energy supplied by the turbine into electrical energy. Low-pole AC synchronous generators of high rated power are used.

3.4 Cooling system A cooling system removes heat from the reactor core and transports it to another area of the plant, where the thermal energy can be harnessed to produce electricity or to do other useful work. Typically the hot coolant is used as a heat source for a boiler, and the pressurized steam from that boiler powers one or more steam turbine driven electrical generators.

3.5 Safety valves In the event of an emergency, two independent safety valves can be used to prevent pipes from bursting or the reactor from exploding. The valves are designed so that they can derive all of the supplied flow rates with little increase in pressure. In the case of the BWR, the steam is directed into the condensate chamber and condenses there. The chambers on a heat exchanger are connected to the intermediate cooling circuit.

3.6 Feed water pump The water level in the steam generator and nuclear reactor is controlled using the feed water system. The feed water pump has the task of taking the water from the condensate system, increasing the pressure and forcing it into either the Steam Generators (Pressurized Water Reactor) or directly into the reactor vessel (Boiling Water Reactor).

Pressurized Water Reactor

3.7 Emergency power supply The emergency power supplies of a nuclear power plant are built up by several layers of redundancy, such as diesel generators, gas turbine generators and battery buffers. If necessary, the emergency power supply allows the safe shut down of the nuclear reactor. Less important auxiliary systems such as, for example, heat tracing of pipelines are not supplied by these back ups. The majority of the required power is used to supply the feed pumps in order to cool the reactor and remove the decay heat after a shut down.

4 Human error There are concerns that a combination of human and mechanical error at a nuclear facility could result in significant harm to people and the environment: Operating nuclear reactors contain large amounts of radioactive fission products which, if dispersed, can pose a direct radiation hazard, contaminate soil and vegetation, and be ingested by humans and animals. Human exposure at high enough levels can cause both short-term illness and death and longer-term death by cancer and other diseases.

5 Future power plants A number of new designs for nuclear power generation, collectively known as the Generation IV reactors, are the subject of active research and may be used for practical power generation in the future. Many of these new designs specifically attempt to make fission reactors cleaner, safer and/or less of a risk to the proliferation of nuclear weapons.

Conclusion We have learned a small part of this idea but we understood how we can be dangerous. We have to be more careful using nuclear power. Our potential is very great. We have very smart scientists which can design a best defense from bad pollution. Nuclear energy has a future!!!

Thank you for attention.