The fuel used in a nuclear reactor usually comes from?
Mines, usually it is uranium, with only 0.7% (aproximately) U-235 (the isotope that is used for fission), the rest is U-238, known as depleted uranium, or natural uranium. Then it enriched to about 3-5% U-235, unless it is used in a CANDU reactor, in which case it can almost literaly be used straight out of the ground.
The used fuel in a nuclear power plant is the nuclear fuel being discharged from the nuclear reactor after being irradiated during reactor operation. It is usually composed of trans-uranium heavy elements, a wide variety of fission products (that resulted from the nuclear fission processes in the nuclear reactor) and products of radioactive decay (produced before and after fuel discharge from the nuclear reactor).
The nuclear fuel of light water Pressurized Water Reactor (PWR) is fabricated as thin nuclear fuel pins assembled in an open square array of usually 17 x 17 or 18 x 18. The assembly usually keeps the central location for instrumentation and keeps also 24 locations to allow, when needed for a control rod spider to pass through in and out. This cluster of fuel pins is usually called fuel assembly.
This is used in the nuclear reactor that is known as Boiling Water Reactor (BWR) in which heat produced by the nuclear fission in the nuclear fuel allows the light water reactor coolant to boil. Then, the nuclear reactor moisture separator is used to increase the dryness of the produced steam before it goes to the reactor steam turbines.
Mainly: Nuclear fuel: where nuclear fission and energy is produced Reactor coolant: to extract heat from fuel Reactor neutron moderator: to reduce neutron energy to thermal range (0.025 ev) Reactor control elements: to control nuclear reaction rate, compensate for fuel burnup, and for shutdown and safety conditions Reflector: to reduce neutron leakage
The length of time we see fuel rods left in the core of a reactor will depend on the time it takes to deplete the nuclear fuel in those rods. Reactor design, specifically fuel rod design, and the rate at which the fuel is consumed during operation all have an effect. Typical life of the fuel in a nuclear reactor at a power station is several years.
A nuclear reactor is an assembly of fuel elements (uranium usually), a moderator which can be ordinary water, heavy water, or graphite, and control rods. The reactor is made to reach criticality when uranium fuel will produce a steady power output as a result of nuclear fissions which release heat. The heat is used to produce steam which feeds a conventional steam turbine/generating unit.
A nuclear meltdown is an informal term for a severe nuclear reactor accident that results in core damage from overheating. A meltdown occurs when the heat generated by a nuclear reactor exceeds the heat removed by the cooling systems to the point which at least one nuclear fuel plate exceeds its melting point.
for pressurized light water reactor type, as an example, the nuclear reactor components are * Reactor vessel (that contains the nuclear fuel and surrounded with water and contains control rod for power control and for safety) * reactor coolant pump * steam generator * reactor pressurizer * piping out of the vessel to the pressurizer, from pressurizer to steam generator, from steam generator to reactor coolant pump, and from pump back to the reactor vessel.