Remote Characterization of CNL Whiteshell Decommissioning Waste
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Abstract
The proposed paper discusses the gamma spectrometry systems designed for waste characterization at Whiteshell Laboratories (WL) site. The site is owned by Atomic Energy of Canada Limited (AECL); established in the early 1960s to conduct nuclear research.
AECL has since discontinued research activities at WL and has contracted Canadian Nuclear Laboratories (CNL) to complete the safe decommissioning, remediation, and restoration of the site.
The WL Waste Management Area (WMA) is used to store low and intermediate-level solid radioactive waste, low-level liquid organic radioactive waste, and small volumes of hazardous industrial chemicals. Radioactive waste with Fissionable Material (FM) and Special Fissionable Material (SFM) are stored in the standpipes and bunkers.
CNL is developing a project to complete the restoration of 171 in-ground standpipes and 7 in-ground bunkers. The restoration scope includes the retrieval, sorting, and repackaging of the waste from the standpipes and bunkers. The waste forms vary in size and radioactivity. Depending on the age of the standpipe, filler material (sand and/or gravel) will be present and likely contaminated as migration of radiation from the waste items is expected.
A first-of-its-kind, remotely operated set of equipment has been designed to support the retrieval, sorting, and repackaging activities. This equipment consists of three mobile units:
- Standpipe Waste Retrieval System (SWRS)
- Bunker Waste Retrieval System (BWRS)
- Sorting and Conditioning Unit (SCU)
The units will be positioned over the standpipes and bunkers to perform waste retrieval, sorting, and repackaging.
Integrated into the aforementioned equipment are gamma spectrometry systems. These systems play a key role in the preliminary screening of waste items (confirmation of FM/SFM), as well as satisfying the requirements of CNL WL’s Criticality Safety Document (CSD) and Waste Acceptance Criteria (WAC) of the CNL storage facility. To support this, specific crystals were selected for the gamma spectrometry systems based on their function.