Validation and Application of Transport Theory Methods for Predicting Neutron Detector Readings in FBR In-Core Shields

摘要

A pool type 500 MWe Prototype Fast Breeder Reactor (PFBR) is under construction in India. It is well known that the neutron flux monitoring system in a pool type fast breeder reactor is a very challenging issue, which involves high complexity. The use of external neutron source subassemblies of Sb-Be type has been explored as a possibility to obtain enhanced neutron detector count rate for the regular startups of PFBR. The neutron flux at the detector location is estimated by Monte Carlo and deterministic neutron transport methods. It is at first estimated by Monte Carlo particle transport code MCNP with continuous energy cross-sections derived from ENDF-B/VI. Later on, a newly developed multi-group neutron transport code Anisotropic Transport Equation Solver in 3-D (ATES3) based on advanced acceleration schemes is also used to estimate the same. A comparison of results obtained by both the methods are also presented. The results are encouraging from the reactor startup point of view and it is inferred from the study that the reactor startup can be hastened with the introduction of the three external neutron source subassemblies.