Operator declaration verification technique for spent fuel at reprocessingfacilities

A verification technique for use at reprocessing facilities, which integrat es existing technologies to strengthen safeguards through the use of enviro nmental monitoring, has been developed at Los Alamos National Laboratory. T his technique involves the measurement of isotopic ratios of stable noble f ission gases from on-stack emissions during reprocessing of spent fuel usin g high-precision mass spectrometry. These results are then compared to a da tabase of calculated isotopic ratios using a data analysis method to determ ine specific fuel parameters (e.g., burnup, fuel type, reactor type, etc.). These inferred parameters call be used to verify operator declarations. Th e integrated system (mass spectrometry, reactor modeling, and data analysis ) has been validated using on-stack measurements during reprocessing of fue l from a US production reactor. These measurements led to an inferred burnu p that matched the declared burnup to within 3.9%. suggesting that the curr ent system is sufficient fur most safeguards applications. Partial system v alidation using gas samples from literature measurements of power reactor f uel has been reported elsewhere, This has shown that the technique develope d here may have some difficulty distinguishing pressurized water reactor (P WR) from boiling water reactor (BWR) fuel; however, it consistently can dis tinguish light water reactor (either PWR or BWR) fuels from other reactor f uel types. Future validations will include advanced power reactor fuels (su ch as breeder reactor fuels) and research reactor fuels as samples become a vailable. (C) 2000 Elsevier Science B.V. All rights reserved.