New MCNPX Capabilities for Nuclear Safeguards

摘要

A number of new capabilities have been developed for the MCNPX [1] radiation transport Monte Carlo computer code specifically for the Next Generation Safeguards Initiative (NGS1) of the DOE Nuclear Safeguards Program, which, in 2009, began a five-year effort to develop an integrated nondestructive assay (NDA) instrument fully capable of determining plutonium mass in, and detecting diversion of pins from, spent commercial fuel assemblies [2]. Characterizing the plutonium or equivalent content in spent nuclear fuel presents many new challenges requiring sophisticated modeling. No single detector is capable, so combinations of various nondestructive assay techniques have been proposed. These make use of delayed neutrons, fission chambers, 3He neutron captures, direct gamma radiation signals, fission multiplicity, coincidence counting, and other passive and active nuclear material assay techniques.