A Methodology for Establishing Zones of Acceptable CAAS Coverage for a New Storage Facility Utilizing MCNP 5 in Adjoint

ANSI/ANS 8.3 “Criticality Accident Alarm System”, Appendix B states “Determining the adequacy of criticality alarm detector placement is far from an exact process”. With this statement in mind a novel method for establishing areas of acceptable Criticality Accident Alarm System (CAAS) coverage was developed and demonstrated utilizing Los Alamos’ Monte Carlo N-Particle Code 5 (MCNP5) in multigroup Adjoint. Validation of the methodology was shown in the comparison of benchmark calculations with empirical results of Sandia testing and with hand calculations utilizing ANS 8.3. Demonstration involved the determination of zones of CAAS coverage from detector sensitivity maps generated by MCNP5 for a conceptual geometry of a new storage facility involving homogenized concrete and BoroBond^® slabs. Multiple detector coverage was further demonstrated through the superimposing of several maps corresponding to differing detector locations.