Thermal-hydraulic transient analysis for heat transport system of thorium-based advanced CANDU reactor

Background: The utilization of thorium in reactors is of great significance to alleviate the shortage of nuclear fuel and Canadian deuterium uranium (CANDU) reactor is one of the best choice to be introduced in thorium fuel cycles. The abundant thorium deposit and rich experience in operating Qinshan phase III laid a foundation for researches on thorium-based advanced CANDU reactor (TACR) in China. Purpose: To support the international cooperative study on TACR between Canada and China and lay a foundation for self-development of the software for CANDU thermal hydraulic analysis in our country, it is necessary to develop analysis code in order to evaluate thermal hydraulic performance of CANDU reactor heat transport system. Methods: In this study, a CANDU thermal hydraulic transient analysis code (CANTHAC) was developed using FORTRAN language and used to analysis the transient performance of TACR heat transport system. The full power steady state, steam generator (SG) feed water temperature reduction accident and complete loss of flow accident were simulated. Results: The steady state results by CANTHAC were in good agreement with the rated value designed by Tsinghua University and the maximum calculation error was less than 2%, which is acceptable. The calculation results of SG feed water temperature reduction accident and complete loss of flow accident shown that key parameters including the fuel temperature and system pressure do not exceed specified limits and satisfy the safety criteria. Conclusion: The steady state results agree well with the rated value and the transient results are reasonable, which preliminarily evaluate the validity of the transient analysis code. Since the code was modularized, it would be convenient for further modification and application.