Numerical simulation of a potential CO2 ingress accident in a SFR employing an advanced energy conversion system

A numerical simulation method for the potential tube rupture and the consequential CO2 ingress accident possibly occurring inside the Na–CO2 heat exchanger of a SFR employing a supercritical CO2 Brayton cycle has been developed. Based on the thermo-chemical considerations and a reasonable hypothesis, the computer code, STASCOR was formulated by reflecting suitable chemical reaction processes and various system models. The physical models implemented in the numerical method were tentatively verified by using a scale-down mock-up test, and it was confirmed that the analysis model and its assumptions feasibly replicate the overall system transients with a physically reasonable understanding. By using the numerical simulation method, the potential pressure boundary failure accident for the shell-and-tube type Na/CO2 heat exchanger was analyzed and the system dynamic responses were systematically evaluated. Based on the analysis results, it was demonstrated that the STASCOR code has the capabilities to simulate a system transient regarding the various design conditions associated with a pressure relief system. The applicability of the numerical simulation method to a micro-channel type heat exchanger, e.g. PCHE, was assessed qualitatively, and the possibility of a self-plugging or self-mitigation against the CO2 ingress accident was discussed as well.