Analysis of Transient Thermal-Hydraulic and Safety of Lead-Cooled Fast Reactor Based on Unified Coupling Framework

Abstract

In order to improve the accuracy of the reactor numerical simulation, a unified framework of multi-scale and multi-physical coupling based on the ICOCO (Interface for Code Coupling) packaging and integration method is constructed by coupling the neutron diffusion code NDK, subchannel codes KMC-SUB and open-source CFD code TrioCFD. By encapsulating the source codes in accordance with the ICOCO specification and writing a unified coupling scheduling (SuperVisor) program, taking the medium-sized modular lead-cooled fast reactor M2LFR-1000 as an example, three-dimensional flow and heat transfer phenomenon under the shutdown condition and unprotected loss of flow accident are studied. The results show that the developed multi-scale and multi-physical coupling analysis tool can more accurately capture the three-dimensional T/H and overall phenomena of the lead-cooled fast reactor. Under the shutdown condition, obvious thermal stratification phenomenon occurs in the upper chamber. Under the asymmetric unprotected loss of flow accident, the thermal parameters of the primary circuit oscillate significantly, and the upper chamber exists thermal stratification, jet mixing, and recirculation flow phenomenon.