Evidence Support Logic for Leak Mitigation

Quintessa is currently working with Jacobs Engineering (UK) to provide decision support to the Magnox Swarf Storage Silo decommissioning project at Sellafield.The Magnox Swarf Storage Silo comprises a series of water-filled concrete waste silos, into which predominantly intermediate level wastes were consigned between 1964 and 1991. Decommissioning of the facility, including the retrieval of past disposals of Magnox fuel cladding, is one of the most complex and difficult challenges for Sellafield Limited.

Defining an approach to waste retrieval that mitigates any leaks that might occur during retrieval operations is a key component of the overall safety management strategy for decommissioning. There is also a need to define a suitable system for responding to and mitigating the impact of any leaks that might occur. The aim of the present study is to support the Sellafield project team in reviewing and updating plans for mitigation of possible leaks to ground.

We are applying Evidence Support Logic, implemented using our TESLA software, to examine alternative approaches to mitigation and to assess the confidence with which they can be expected to achieve defined goals. This is a facilitated process, in which we work with experts at Sellafield, as well as external specialists, to develop a rationale for defining interactions between lines of evidence relevant to determining the preferred strategy. The intention is to build consensus by engaging different perspectives in structuring the complex issues involved and interpreting the available evidence.

Image Courtesy of Sellafield Ltd.