Research on simplification of branches method of accident sequences based on expert knowledge and heuristic optimization algorithm

Abstract

The simplification of branches method of accident sequences based on expert knowledge and heuristic optimization algorithm is proposed in this paper, to increase the effectiveness of nuclear power plant safety margin analysis. First, the classification criteria for accident sequence and expert knowledge are used to screen out the deterministic failure sequences and deterministic safety sequences that are obviously. Secondly, a heuristic optimization method is used to study the variation in the accident sequences for those accident sequences that are challenging to evaluate with expert knowledge. Moreover, a hybrid particle swarm optimization (HPSO) is proposed to increase the accuracy of key safety parameters. This enables efficient accident sequence type identification, by comparing and evaluating key safety parameters and safety limits. Finally, the accident sequences are simplified using the cut-off frequency. To verify the effectiveness of the method, the small break loss of coolant (SBLOCA) accident in the nuclear power plant is analyzed in this paper. The numerical results show that the proposed HPSO improved the accuracy of solving the key safety parameters of accident sequences compared with the traditional method. By simplifying the accident sequences, the number of accident sequences requiring further analysis was reduced from 64 to 5.