The Role of Piece Monitors for the Assay of Plutonium Waste in Alpha Plant Decommissioning Operations
- BIL Solutions Ltd., Cumbria, CA20 1PG (United Kingdom)
Plutonium contaminated (TRU) wastes arising during decommissioning and waste retrievals operations at a UK reprocessing facility include small process items, strippable coatings, size-reduced pieces of glove box and metal pipes, etc. These waste materials are generally assayed in a 'Piece Monitor' employing neutron coincidence counting and gamma assay technologies. The major function of the TRU D{sup R} Piece Monitor is to provide an accurate assay of the TRU content of waste pieces/packages, primarily for nuclear safety purposes. The Piece Monitor follows each waste measurement by calculating the cumulative plutonium content of a waste drum as it is filled with this waste, allowing maximum filling of the drum whilst ensuring it remains within fissile content limits. TRU Piece Monitors are deployed at the interface between clean-air (C2) and the active decommissioning (C5) areas by attaching them to the wall of removable modular containment structures (MCSs). In the C5 area, the plant operator uses a variety of cold-cutting processes to size-reduce plant equipment and then places waste items in the monitor chamber for assay, prior to placing the waste in a 200 litre drum. The 're-entrant bulge' design of the assay chamber provides access from the active operations side, whilst the detection equipment remains in the C2 area. This ensures that the Piece Monitor equipment does not become contaminated and remains readily accessible for maintenance or repair. Piece monitors measure and report the plutonium content of each waste item immediately prior to placing in the waste drum, and provides a continuous 'tally' of the drum content. Warnings are shown when a drum is close to exceeding its allowable plutonium content and the waste drum can therefore be changed when either physically full or nearing its nuclear safety limits. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 21326157
- Report Number(s):
- INIS-US-10-WM-08425; TRN: US10V0606067522
- Resource Relation:
- Conference: WM'08: Waste Management Symposium 2008 - HLW, TRU, LLW/ILW, Mixed, Hazardous Wastes and Environmental Management - Phoenix Rising: Moving Forward in Waste Management, Phoenix, AZ (United States), 24-28 Feb 2008; Other Information: Country of input: France; 4 refs
- Country of Publication:
- United States
- Language:
- English
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