[en] Rupture of boiling water reactor nuclear fuel cladding resulting from embrittlement caused by fission product cadmium is prevented by adding the stoichiometrically equivalent amount of CuFe2O4 or CuTi03 to the fuel

[en] Rupture of boiling water reactor nuclear fuel cladding resulting from embrittlement caused by fission product cadmium is prevented by adding the stoichiometrically equivalent amount of gold, silver or palladium to the fuel

[en] Rupture of boiling water reactor nuclear fuel cladding resulting from embrittlement by fission product cadmium is prevented by adding the stoichiometrically equivalent amount of V2O4 or V2O5 to the fuel

[en] Cadmium plays a major role in the embrittlement of zirconium alloy fuel cladding materials. It has been discovered that V₂O₄ or V₂O₅ or their mixtures, gold, silver, palladium and their mixtures, and CuFe₂O₄ and CuTiO₃ and their mixtures can prevent embrittlement caused by cesium. These substances may be added to uranium, plutonium or thorium oxide fuels in an amount between 0.0025 and 0.025 weight percent

[en] In the operation of a BWR reactor, very small amounts of cadmium are produced in the decay of nuclear fuel (UO₂- and/or PuO₂ compounds). This leads to an embrittlement of the zirconium alloy fuel cans. According to the invention, CuFe₂O₄ and/or CuTiO₃, added to the nuclear fuel, holds back the Cd produced by a chemical reaction, so that there will be no embrittlement. An addition of about 0.01 percent by weight (referred to the amount of nuclear fuel) appears to be sufficient. (HP)

[en] It has been found that a substantial reduction in metal embrittlement or stress corrosion cracking from fuel pellet-cladding interaction can be achieved by the employment of a copper layer or liner in proximity to the nuclear fuel and an intermediate zirconium oxide barrier layer between the copper layer and the zirconium cladding substrate. Although copper cannot be directly electroplated onto non-conducting zirconium oxide, modification of the zirconium cladding surface prior to oxidation allows for copper deposition by electroless plating

[en] A nuclear fuel element consisting of a zirconium or zirconium alloy container and nuclear fuel pellets is provided for use in the core of a nuclear reactor. The zirconium or zirconium alloy container has an inner coating of copper in proximity to the nuclear fuel, and is separated from the zirconium or zirconium alloy by an intermediate zirconium oxide diffusion barrier layer. The copper layer and the intermediate zirconium oxide diffusion barrier of the composite cladding reduce perforations or failure in the zirconium or zirconium alloy cladding substrate caused by stress corrosion cracking or metal embrittlement. Good bonding of the copper to the oxide zirconium and zirconium alloy prevents scaling of copper from the composite cladding during the loading of the fuel element with fuel pellets

[en] The possibility of undesired interactions between the pellets (of UO₂ or a mixture of UO₂ + PuO₂) and the cladding which can cause stress crack corrosion, are to be excluded in particular in the proposed fuel element. The container enclosing the fuel consists according to the invention of a zirconium alloy having a zirconium oxide diffusion barrier on the side facing the fuel and a metal coating on top of this. Cu is best suited, but Ni, Fe or their alloys are named. The treatment of the surfaces to simplify the coating of the individual layers is described. (UWI) 891 HP/UWI 892 CKA

[en] The invention is based on the discovery that a substantial reduction in metal embrittlement or stress corrosion cracking from fuel pellet-cladding interaction can be achieved by the use of a copper layer or liner in proximity to the nuclear fuel, and an intermediate zirconium oxide barrier layer between the copper layer and the zirconium cladding substrate. The intermediate zirconia layer is a good copper diffusion barrier; also, if the zirconium cladding surface is modified prior to oxidation, copper can be deposited by electroless plating. A nuclear fuel element is described which comprises a central core of fuel material and an elongated container using the system outlined above. The method for making the container is again described. It comprises roughening or etching the surface of the zirconium or zirconium alloy container, oxidizing the resulting container, activating the oxidized surface to allow for the metallic coating of such surfaces by electroless deposition and further coating the activated-oxidized surface of the zirconium or zirconium alloy container with copper, iron or nickel or an alloy thereof. (U.K.)

[en] Cadmium severely embrittles Zircaloy-2. The phenomenon was observed to occur with solid cadmium at 300/degree/C, liquid cadmium at 340/degree/C, and cadmium dissolved in liquid cesium over a range of temperatures. In liquid cesium alone at 300/degree/C, high reduction of area and only ductile fracture morphology was observed. The effect of texture was briefly evaluated using tensile samples machined from cross-rolled plate in different orientations. The results are presented in terms of fractography, and stress-elongation data obtained by constant extension rate tensile tests. 23 refs