Benefits of low resolution gamma spectroscopy (LRGS) in assessment and remediation of alpha contamination - 16023

The legacy of alpha contamination in an exterior disused storage area at the Low Level Waste Repository (LLWR) presented difficult challenges with regard to assessment and remediation. The area was heavily overgrown, with degraded remnant surfaces and debris from past demolition activities. The use of conventional field instruments and/or an extensive intrusive sampling programme were precluded as being impractical, the latter prohibitively costly and not expeditious. This paper describes the identification of a cost-effective alternative for the initial site assessment and the role of LRGS in the subsequent remediation work. It includes: 1 - identification and selection of a field instrumentation/system for investigating the site. 2 - details of the TERRIERTM system, incorporating the SAM935 Low Resolution Gamma Spectrometer (LRGS) with the capability of real time identification of nuclides. 3 - use of the TERRIERTM for a non-intrusive survey of the site, with rapid transformation of field data into informative plots useful for remediation planning. 4 - use of the TERRIERTM during remediation work, including assay of arisings. 5 benefits and limitations of using LRGS to support remediation of alpha contamination. 6 application of the instrumentation/system to other radiological investigations. (authors)