Release of Materials During the Decommissioning of the Belgonucleaire Dessel MOX Fuel Fabrication Plant

Abstract

BELGONUCLEAIRE has been operating the Dessel plant from the mid-80’s at industrial scale. In this period, over 35 metric tons of plutonium (HM) has been processed into almost 100 reloads of MOX fuel for commercial west-european light water reactors. In late 2005, the decision was made to stop the production because of the shortage of the MOX fuel market remaining accessible to BELGONUCLEAIRE. As a significant part of the decommissioning project of this Dessel plant, about 170 medium-sized glove boxes and about 1.300 metric tons of structure and equipment outside the glove boxes are planned for dismantling. The dismantling works are expected to start in the second quarter of 2009. On account of stringent internal rules of alpha-containment during over 25 years of operation, there is no significant contamination of the plant, outside the glove boxes; that assumption has been confirmed by radiological surveys performed by independent bodies in 2001 and 2008. Therefore most of the materials outside the glove boxes that were not a priori destined for radioactive waste will be released without restriction on the basis of the applicable legal regulations in Belgium (ARBIS), along with the buildings and the plant site. In this paper, after having reviewed the different regulations in Belgium, the authors introduce the different options considered for release of materials, and the main decision criteria (process, safety aspects, radiological, etc) for the different expected types of materials (inert materials, metals, plastics, electrical cabinets and cables and electronics) are analysed. Besides the regulatory aspects, the technological and economical aspects are considered (as an example, comprehensive metal smelting is implemented, as a favourite solution because it provides with decontamination, homogeneization and volume characterization).