Examine individual changes

'[[Image:Wwer-1000-scheme.png|thumb|Example of the core of a nuclear power plant, a [[VVER]] design.]] A '''nuclear reactor core''' is the portiSuck MY DICK HOESon of a [[nuclear reactor]] containing the [[nuclear fuel]] components where the [[Nuclear fission|nuclear reactions]] take place and the heat is generated. Typically, the fuel will be low-enriched uranium contained in thousands of individual fuel pins. The core also contains structural components, the means to both moderate the neutrons and control the reaction, and the means to transfer the heat from the fuel to where it is required, outside the core. == Water-moderated reactors == Inside the core of a typical [[pressurized water reactor]] or [[boiling water reactor]] are nuclear fuel rods equivalent to the diameter of a large gel type ink-pen, each about 4 m long, which are grouped by the hundreds in bundles called "fuel assemblies". Inside each fuel rod, pellets of uranium, or more commonly uranium oxide, are stacked end to end. Also inside the core are [[control rods]], filled with pellets of substances like [[boron]] or [[hafnium]] or [[cadmium]] that readily capture [[neutron]]s. When the control rods are lowered into the core, they absorb neutrons, which thus cannot take part in the [[chain reaction]]. Conversely, when the control rods are lifted out of the way, more neutrons strike the [[fissile]] [[uranium]]-235 (U-235) or [[plutonium]]-239 (Pu-239) nuclei in nearby fuel rods, and the [[nuclear chain reaction|chain reaction]] intensifies. The [[core shroud]], also located inside of the reactor, directs the water flow to cool the nuclear reactions inside of the core. The heat of the fission reaction is removed by the water, which also acts to [[neutron moderators|moderate]] the neutron reactions. An alternative form of nuclear fuel would be [[fissile]] [[uranium]]-233 (U-233) made by the neutron-bombardment of the common [[thorium]]-232. == Graphite-moderated reactors == [[Image:MSRE Core.JPG|right|200px|thumb|Graphite [[Molten-Salt Reactor Experiment]] core]] There are also [[Graphite moderated reactor]]s in use. One type uses solid graphite for the [[neutron moderator]] and ordinary water for the coolant. See the Soviet-made [[RBMK]] nuclear-power reactor. This was the type of reactor involved in the [[Chernobyl disaster]]. In the [[advanced gas-cooled reactor]], a British design, the core is made of a graphite [[neutron moderator]] where the fuel assemblies are located. [[Carbon dioxide]] gas acts as a coolant and it circulates through the core, removing heat. There have also been several experimental reactors that use graphite for moderation, such as the [[pebble bed reactor]] concepts and the [[molten-salt reactor experiment]] (graphite core shown at right). ==See also== {{portal|Nuclear technology}} *[[Nuclear meltdown]] *[[Lists of nuclear disasters and radioactive incidents]] *[[Nuclear power]] *[[Nuclear reactor technology]] ==References== *Nuclear Reactor Analysis, John Wiley & Sons Canada, Ltd. [[Category:Nuclear power plant components]] [[Category:Nuclear technology]]'