Preventing Fuel Failure for a Beyond Design Basis Accident in a Fluoride Salt-Cooled High-Temperature Reactor

摘要

The fluoride salt-cooled high-temperature reactor (FHR) combines high-temperature coated-particle fuel with a high-temperature salt coolant for a reactor with unique market and safety characteristics. This combination may eliminate large-scale radionuclide releases by avoiding major fuel failure during a catastrophic Beyond Design Basis Accident (BDBA). A BDBA system may prevent major fuel failure even if there is a large-scale reactor accident and vessel failure. If there is no major fuel failure, there can be no large radionuclide release. A 1047 MWth FHR was modeled using the STAR-CCM+ computational fluid dynamics package. Peak temperatures and heat transfer phenomena were calculated, focusing on the feasibility of melting a BDBA salt to improve heat transfer from vessel to silo during a BDBA. A simplified wavelength-independent radiation model was examined to approximate the heat transfer capability with radiation heat transfer. The FHR BDBA system kept peak temperatures below fuel- failure point in all modeled cases.