A CAPSULE FOR THE CONTAINMENT OF SPENT NUCLEAR FUEL AND A METHOD OF MANUFACTURING SUCH A CAPSULE

摘要

The invention relates to a capsule for the containment of spent nuclear fuel, wherein the capsule has a cylindrical part which comprises a steel cylinder tightly embraced by a copper layer whose thickness is of the same order as the thickness of the cylinder wall. The copper layer is a continuous layer applied electrolytically over the outer surface of the steel cylinder and has an homogenous grain structure. The invention also relates to a method of producing capsules for the containment of spent nuclear fuel, wherein a steel cylinder of predetermined length and diameter is placed as a cathode in an electrolytic cell containing a copper salt solution as electrolyte. An electric current whose strength is effective in precipitating copper is passed through the cell to the steel cylinder via one or more anodes, while rotating the cylinder, until a copper coating of predetermined thickness has been formed on the outer surface of the cylinder. The copper-coated cylinder is then heated to a temperature and for a period of time that will ensure that the whole of the inhomogenous copper-grain structure formed in the electrolysis process is converted to a structure having a predetermined homogenous grain size. The coated cylinder is then cooled as rapidly as possible, so as to maintain essentially the copper-layer structure of homogenous grain size.