Review of conceptual design and fundamental research related to the passive residual heat removal system in molten salt reactors

The molten salt reactor (MSR) is one of the six advanced reactor concepts declared by the Generation IV International Forum (GIF), which can be characterized by attractive attributes such as inherent safety, sustainable development, nuclear non-proliferation, natural resource protection, and economic efficiency. Passive residual heat removal systems for MSRs predominantly encompass Direct Reactor Auxiliary Cooling Systems (DRACS), Salt Discharge Tanks Residual Heat Removal Systems (DTRHRS), and Heat Pipes Residual Heat Removal Systems (HPRHRS). This study introduces an innovative Secondary Side Passive Residual Heat Removal System (SSHRS) for MSRs. The SSHRS employs the primary heat exchanger to dissipate the residual heat from the fuel salt in the primary loop, eliminating the necessity for an additional residual heat removal exchanger and enhancing economic efficiency. The SSHRS approach prevents direct heat transfer from the fuel salt to the environment, mitigates the risk of radioactive material leakage, and bolsters safety. Furthermore, this study also made a horizontal comparison of the advantages and disadvantages of DRACS, DTRHRS, and SSHRS in terms of safety and economy, and discussed the future research directions of passive residual heat removal from molten salt reactors.