purpose of fuel rods in a nuclear reactor
Nuclear fuel Uranium dioxide (UO2) powder is compacted to cylindrical pellets and sintered at high temperatures to produce ceramic nuclear fuel pellets with a high density and well defined physical properties and chemical composition. A grinding process is used to achieve a uniform cylindrical geometry with narrow tolerances. Such fuel pellets are then stacked and filled into the metallic tubes. The metal used for the tubes depends on the design of the reactor. Stainless steel was used in the past, but most reactors now use a zirconium alloy which, in addition to being highly corrosion-resistant, has low neutron absorption. The tubes containing the fuel pellets are sealed: these tubes are called fuel rods. The finished fuel rods are grouped into fuel assemblies that are used to build up the core of a power reactor.
Thermonuclear weapon A thermonuclear weapon is a second-generation nuclear weapon design using a secondary nuclear fusion stage consisting of implosion tamper, fusion fuel, and sparkplug which is bombarded by the energy released by the detonation of a primary fission bomb within, compressing the fuel material (tritium, deuterium or lithium deuteride) and causing a fusion reaction. Some advanced designs use fast neutrons produced by this second stage to ignite a third fast fission or fusion stage. The fission bomb and fusion fuel are placed near each other in a special radiation-reflecting container called a radiation case that is designed to contain x-rays for as long as possible. The result is greatly increased explosive power when compared to single-stage fission weapons. The device is colloquially referred to as a hydrogen bomb or, an H-bomb, because it employs the fusion of isotopes of hydrogen.[1]