Modeling and Optimization of Gamma Measurement Subsystem Based on NPL-NMC System

The non-destructive analysis is usually employed to measure attributes of mass, isotopic ratio and age for nuclear component in arm control and verification scenario.The NPL-NMC system was developed with making use of neutron multiplicity principle for measuring mass attribute of plutonium and HEU in arm control and verification scenario. To build a comprehensive verification system for nuclear component, attributes of isotopic ratio and age for plutonium and HEU needed to be confirmed by the non-destructive gamma measurement. Therefore, a gamma measurement sub-system based on the NPL-NMC system was modeled and the neutron shield for protecting the gamma system from neutron damage was optimized. The isotopic ratio and age attributes for HEU could be analyzed. The calculation result indicates that it is effective for attribute measurement for isotopic ratio and age of HEU, which satisfies the requirement of establishing an integrate attribute measurement system in arm control and verification scenario.