Multi-objective optimal design of vertical natural circulation steam generator

• We proposed a hybrid non-dominated sorting genetic algorithm.
• An accurate Qinshan nuclear power plant RELAP5 model is built.
• Steam generator mathematical model is modified by RELAP5/MOD3.2 code.
• Sensitivity analysis of steam generator is made.
• Multi-objective optimization of steam generator is conducted and analyzed.

In this work, a hybrid non-dominated sorting genetic algorithm was proposed and utilized to perform the multi-objective optimization design of a natural circulation steam generator, which included minimizing of the weight, the volume and the reactor coolant flow-rate. Sensitivity analysis of the design variables was carried out to study the relationships between the optimization variables and the objective functions, which was also helpful for the explanation of the optimization results. The mathematical model of the steam generator was validated by the RELAP5 code. The results show that the mathematical model has a good agreement with the RELAP5 model after modifying the boiling correlation in the secondary side; the proposed hybrid non-dominated sorting genetic algorithm is able to find much better spread of solutions and better convergence near the true Pareto optimal front compared to the non-dominated sorting genetic algorithm; reactor inlet temperature is the most important variable which influences the distribution of Pareto optimal solutions.