RECYCLING OF COPPER USED IN FUSION POWER-PLANTS

One of the major safety and environmental advantages of fusion power i s a limited waste management burden on future generations. In this con nection, the ability to recycle end-of-service materials from fusion p ower plants is beneficial both in terms of the conservation of natural resources and the minimisation of the volume of activated wastes. Aft er 100 years, the residual activity of near-plasma copper components e xceeds that permitted for free release or contact handling. The presen ce of silver as a common impurity in copper may exacerbate this proble m, through generation of Ag-108m. Removal of the silver impurity in a separate refining step prior to use of the copper in a fusion plant ob viates the problems associated with formation of Ag-108m. TWO alternat ive desilverisation processes have been demonstrated; one involving th e segregation of silver as AgBr and the other the absorption of Ag+ by ion exchange. The present study demonstrates that conventional electr orefining techniques can be adapted to recover used copper in a single refining stage, with sufficient decontamination to permit its reuse i n fusion power plants or, with a second stage, unrestricted release. S hielding requirements for the processing of scrap copper in convention al hot cells indicate a decay storage period of 50-100 years. To maxim ise the cost savings of reclamation over direct geological disposal, t he activation products may be separated out and disposed of in a metal lic form. A substantial reduction in the overall volume of active wast e should thus be achievable, especially if supercompaction can be appl ied to the product. (C) 1998 Elsevier Science S.A. All rights reserved .