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An Advanced ISOCS In Situ Gamma Spectrometry Services Tool to Reduce Uncertainties in Waste Characterization Projects - 16311

Conference ·
OSTI ID:22838152
; ;  [1]; ; ; ;  [2]
  1. Canberra UK Ltd, 528.10 Unit 1, Harwell Oxford, Didcot, Oxfordshire, UK, OX11 0DF (United Kingdom)
  2. Canberra Industries, 800 Research Pkwy, Meriden, CT 06450 (United States)
Canberra's In Situ Object Counting System (ISOCS) is an established tool used for gamma spectrometry allowing a physical representation of complex geometries and mathematical calculation of the calibration function. It avoids the need for radioisotope standards which can be costly and prohibitively difficult to produce. Uncertainties in the sample - detector geometry lead to uncertainties in the calibrations. Canberra's ISOCS Uncertainty Estimator (IUE) tool offers an automated means of accommodating known model geometry uncertainties, with calculation of robust defensible calibration uncertainties. However these uncertainties may be large leading to potential over-estimation of under-estimation of activity. This can be equated directly to waste disposal costs if one is using ISOCS for waste sentencing to classify wastes as (for example) Transuranic Waste (TRU) or Low Level Waste (LLW). An Advanced ISOCS in-situ Gamma Spectrometry (AIGS) services tool has been developed to reduce the uncertainties. This system is based on generating and comparing geometry models that yield Figures of Merit (FoM) indicative of improved consistency between modelled data and available diverse measurement data. This paper describes the development and features of AIGS, focusing on recent testing with radioisotope sources in a 200 litre drum filled with a simulated waste matrix. The results demonstrate a significant advantage for Am-241 where uncertainties can otherwise amount to a factor of 2 or more. We show how our specialist teams can develop procedures for deployment of standard ISOCS hardware, adapting measurement geometries and procedures through careful planning, to provide data that can be used to greatly reduce the uncertainties in the measured activities. Lastly, we comment on the range of potential applications for this new technique and the wider benefits for the decommissioning industry. (authors)
Research Organization:
WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
OSTI ID:
22838152
Report Number(s):
INIS-US--19-WM-16311
Country of Publication:
United States
Language:
English