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Cladding is the outer layer of the fuel rods, standing between the coolant and the nuclear fuel. It is made of a corrosion -resistant material with low absorption cross section for thermal neutrons , usually Zircaloy or steel in modern constructions, or magnesium with small amount of aluminium and other metals for the now-obsolete Magnox reactors .
One of the main uses of zirconium alloys is in nuclear technology, as cladding of fuel rods in nuclear reactors, especially water reactors. A typical composition of nuclear-grade zirconium alloys is more than 95 weight percent [ 1 ] zirconium and less than 2% of tin , niobium , iron , chromium , nickel and other metals, which are added to ...
This page describes how uranium dioxide nuclear fuel behaves during both normal nuclear reactor operation and under reactor accident conditions, such as overheating. Work in this area is often very expensive to conduct, and so has often been performed on a collaborative basis between groups of countries, usually under the aegis of the Organisation for Economic Co-operation and Development's ...
The fuel cladding is the first layer of protection around the nuclear fuel and is designed to protect the fuel from corrosion that would spread fuel material throughout the reactor coolant circuit. In most reactors it takes the form of a sealed metallic or ceramic layer.
A fuel element failure is a rupture in a nuclear reactor's fuel cladding that allows the nuclear fuel or fission products, either in the form of dissolved radioisotopes or hot particles, to enter the reactor coolant or storage water. [1] The de facto standard nuclear fuel is uranium dioxide or a mixed uranium/plutonium dioxide.
Caesium-134 is found in spent nuclear fuel but is not produced by nuclear weapon explosions, as it is only formed by neutron capture on stable Cs-133, which is only produced by beta decay of Xe-133 with a half-life of 3 days. Cs-134 has a half-life of 2 years and may be a major source of gamma radiation in the first 20 years after discharge.
The Chernobyl corium is composed of the reactor uranium dioxide fuel, its zircaloy cladding, molten concrete, as well as other materials in and below the reactor, and decomposed and molten serpentinite packed around the reactor as its thermal insulation. Analysis has shown that the corium was heated to at most 2,255 °C (4,091 °F), and ...
The five criteria for ECCS are to prevent peak fuel cladding temperature from exceeding 2200 °F (1204 °C), prevent more than 17% oxidation of the fuel cladding, prevent more than 1% of the maximum theoretical hydrogen generation due the zircalloy metal-water reaction, maintain a coolable geometry, and allow for long-term cooling.