The role of non-destructive assay in support of the exemption of solid waste from nuclear licensed sites

Available in abstract form only. Full text of publication follows: Nuclear Site License Holders within the United Kingdom are increasingly re-examining the options available for disposal of solid waste produced during routine operations and decommissioning activities. The incentives to do so include: 'Compliance with the requirement to minimise radioactive waste, as stipulated in Disposal Authorisations issued by the Environment Agency' Reducing the burden on the UK Low Level Waste Repository (LLWR)' Achieving cost savings on waste management, by avoiding expensive conditioning, transport and disposal costs for certain wastes. Wastes may be exempted from regulation under the Radioactive Substances Act, 1993 (RSA 93) provided they comply with the conditions laid out in the relevant Exemption Orders. In effect, they may be legally disposed as if they were non-radioactive waste. A national Code of Practice on Clearance and Exemption Principles, Processes and Practices was introduced in 2005 to clarify the requirements of these Exemption Orders and provide guidance on their practical application. In order to demonstrate compliance with these Exemption Orders, it is essential to have good knowledge of the items' history and their potential for contamination. Monitoring is frequently used as definitive evidence that the radioactivity content of waste items does not exceed limits proscribed in the relevant Exemption Orders. The practicalities of monitoring require careful consideration in order to achieve meaningful results and be capable of achieving the low specific activity limits quoted in the Exemption Orders. The Cross Industry Assay Working Group is a national collection of non-destructive assay specialists from a range of companies, which meets regularly to discuss challenges relating to the assay of all categories of waste. In this paper, the Group presents examples of how NDA techniques are being used to support the exemption of waste items. (authors)