Modification and application of Relap5 Mod3 code to several types of nonwater-cooled advanced nuclear reactors

Nonwater fluids have been widely adopted in the designs of several advanced nuclear reactors, especially the fourth-generation nuclear reactors and International Thermonuclear Experimental Reactor (ITER) blankets. Relap5 Mod3, initially developed for the water-cooled nuclear reactors, can continue to be applied to conduct the transient analysis of nonwater-cooled nuclear reactor systems as recommended. Thermodynamic and transport properties of fluoride salts, sodium, and lithium-lead eutectic are summarized and embedded into the Relap5 Mod3 code. Flow and heat transfer empirical correlations specific for low-Prandtl-number liquid metal and high-Prandtl-number fluoride salts are also added into the corresponding modules of the code. Through the benchmark problems including the protected loss of forced cooling of Mark1 pebble bed fluoride-salts-cooled high-temperature reactor and the Shutdown Heat Removal Test (SHRT) 17 of Experimental Breeder Reactor II, the modified Relap5 Mod3 has been verified and validated for the transient simulation of the fluoride-salt-cooled high-temperature reactors and sodium-cooled fast reactors. An ITER demo lithium-lead eutectic blanket, China Dual-Functional Lithium-Lead Test Blanket Module (DFLL-TBM), also proves safe under the protected loss of forced cooling accident through the analysis of the modified Relap5 Mod3.