AN INFORMAL EXPERT JUDGMENT ASSESSMENT OF SUBSIDENCE MITIGATION OPTIONS FOR LOW-LEVEL RADIOACTIVE WASTE MANAGEMENT SITES ON THE NEVADA TEST SITE

An assessment of options to mitigate the effects of subsidence at low-level radioactive waste disposal sites on the Nevada Test Site was conducted using an informal method of expert judgment. Mitigation options for existing waste cells and future waste cells were identified by a committee composed of knowledgeable personnel from the DOE and DOE-contractors. Eight ranking factors were developed to assess the mitigation options and these factors were scored through elicitation of consensus views from the committee. Different subsets of the factors were applied respectively, to existing waste cells and future waste cells, and the resulting scores were ranked using weighted and unweighted scores. These scores show that there is a large number of viable mitigation options and considerable flexibility in assessing the subsidence issue with a greater range of options for future waste cells compared to existing waste cells. A highly ranked option for both existing and future waste cells is covering the waste cells with a thick closure cap of compacted native alluvium