Multi-objective optimal design for the coolant system of a pressurized power reactor and its validation by the RELAP5/MOD3.2 code

•Multi-objective optimization of a reactor coolant system is conducted.•An optimal scheme is verified by the RELAP5/MOD3.2 code.•This work provides a reference for a typical PWR design.

The preliminary design of a nuclear power plant could be optimized with satisfying design requirements and safety regulations. Optimization methodology is of great importance for the design of a nuclear power plant in such cases that either space or weight is limited. In this work, a mathematical model package, which is used to evaluate the weight and volume of the reactor coolant system in Qinshan I nuclear power plant, was built and verified. The parameters, which influence the weight or volume of the system greater than others, were selected as optimization variables through the sensitivity analyses. Then the optimization was performed by means of the immune memory clone constraint multi-objective algorithm. The results show that the model is reliable for the evaluation of the reactor coolant system. The weight and volume of the system could be at least reduced by 9.71% and 8.16% respectively as compared to the prototype after being optimized. An optimal scheme was verified by the RELAP5/MOD3.2 code, the results show that the reactor core safety could be ascertained under station blackout accident and small break loss of coolant accident.