Research and Application of Minimum Critical Accident Alarm System Layout Method

To meet the requirements of the national standard and the design requirement of the critical accident alarm system (CAAS) in reprocessing plants, a CAAS design method is proposed to deal with complex structure and strong background dose in reprocessing plant buildings with many equipment. The design method is consist of the analysis of the envelope minimum criticality accident source term of reduced model, and the confirmation of uncertainty of the calculation method, which are both based on the characteristics of equipment geometry, type and concentration of solution contained. In addition, forward weighted consistent adjoint driven importance sampling (FW-CADIS) method is used to accelerate the convergence speed. This design method is applied to the CAAS design of reprocessing plants, and the result shows that the CAAS location and alarm threshold of the target building meet the requirement of national standard. Compared with the calculation results of commercial Monte Carlo code, the results are similar and the efficiency is higher, so the feasibility, correctness and efficiency of this method are proved. Therefore, the method in this paper can be applied in the CAAS design of reprocessing plants, and has good accuracy and speed.