Development of optimization platform and its application in severe accident management

Highlights: • An optimization platform based on downhill simplex algorithm is developed to search the optimized strategy automatically. • The optimization platform is used to search the optimized RCS depressurization strategy under a SBO accident successfully. • The efficiency of optimization platform is 12 times than the traditional enumeration algorithm. • It is expected that the optimization platform could be applied to other severe accident management study in the future. The consequence of severe accident can be alleviated by proper severe accident management (SAM). Variety of schemes have been developed to seek optimized SAM strategy for many given accident sequences. In this paper, an optimization platform based on downhill simplex algorithm is developed. Mathematically speaking, the scheme enables automatic finding of optimum of a function in terms of maximum or minimum, which does not require derivatives. The optimization platform is applied to find the optimized depressurization strategy of reactor coolant system aiming at maximizing the reactor vessel failure time for CPR1000 nuclear power plant in a station blackout (SBO) accident. The application process is compared against that with a traditional enumeration algorithm. The comparison shows that the new optimization scheme is about 12 times more efficient than the traditional one, making the new scheme a better candidate to the efficient and appropriate decision-making tool for SAM. It may be applied to other severe accident management study in the future.