Combining chemical decontamination and melting for volume reduction of metals originally classified as ILW - 000107

In a BWR, the upper reactor internals, i.e. the steam separators and the steam dryer converts the hot water to a dry steam for the turbines. These components have due to the distance to the reactor core low to very low levels of neutron activation, if any. The contamination of these components is usually significant and consists of both loose and fixed contamination incorporated in the oxide layers. The upper reactor internals on a BWR are quite voluminous in relation to their weight, has a complex geometry and are therefore time consuming to cut in pieces that allows high density packing in waste disposal containers for ILW. The incentives for decontamination of the components down to levels that allow melting for volume reduction are therefore high. A performed full-scale treatment project on a steam dryer confirms the significant volume reduction. The steam dryer was decayed prior to segmentation and melting for volume reduction. Cyclife/EDF has, since significant volume reduction is within reach if the inventory of gamma emitting nuclides and by then the dose rate can be reduced, taken benefit of chemical decontamination studies and an analyze of potential treatment results. The analyze confirm that high decontamination factors can be achieved and that the acceptance criteria for melting can be met, with margin. Full scale chemical decontamination results achieved by Framatome and others do align fairly well with the test results. Even without the option of clearance/recycling of the metals, due to high residual activity, a high or very high volume reduction factors can be achieved by melting as well as a potential reclassification of the waste category in a disposal perspective. One key aspect for success is to keep the volume of the secondary waste from the decontamination process down and to make sure that the waste form fulfils the requirements for disposal. (authors)