Nuclear+Reactor

Nuclear Reactor
Nuclear reactors are devices to initiate and control a sustained nuclear chain reaction. The most common use is for generation of electrical power. The heat from the nuclear fission is used to raised steam, which intern powers either ships ,propulsion or electrical generators.

**HOW IT WORKS**
Conventional power stations generate electricity by the thermal energy released from burning fossil fuels, nuclear reactors convert the thermal energy released from nuclear fission.

FISSION Fission is when a large fissile atomic nucleus such as uranium-235 or plutonium-239 absorbs a neutron, it may undergo nuclear fission. The heavy nucleus splits into two or more lighter nuclei, releasing kinetic energy, gamma radiation and free neutrons.



HEAT GENERATION The core of the reactor has a number of ways to generate heat. The kinetic energy of fission products is converted to thermal energy when these nuclei collide with atoms. Some gamma rays produced during fission are absorbed by the reactor, their energy being covered to head. Heat produced by radioactive decay of fission products and materials that have been activated by neutron absorption. This decay heat source will remain for some time even after the reactor is shut down.

COOLING A nuclear reactor coolant is usually water but sometimes a gas or a liquid metal or molten salt. Nuclear reactor coolant is circulated past the reactor core to absorb the heat is carried away from the reactor and is then used to generate steam. Most reactor systems have a cooling system that is physically separated from the water that will be boiled to produce pressurized water reactor.

REACTIVITY CONTROL The power output of the reactor is adjusted by controlling how many neutrons are able to create more fissions. Control rods made of neutron poison are used to absorb neutrons. Absorbing more neutrons in a control rod means that there are fewer neutrons available to cause fission, so pushing the control rod deeper into the reactor will reduce its power output, and extracting the control rod will increase it.

[|Wikipedia-Nuclear reactor technology]
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