Preliminary investigation on the primary heat exchanger lower head rupture accident of forced circulation LBE-cooled fast reactor

The problem about the interaction between heavy liquid metal and water is one of the grand challenges in the development of lead or Lead-Bismuth Eutectic (LBE) cooled fast reactor. In this paper, the primary heat exchanger lower head rupture (HXLHR) accident of a forced circulation LBE-cooled fast reactor was simulated with a transient analysis code NTC (Neutronics and Thermal-hydraulics Coupled transient analysis program). The simulation results showed that the water in primary heat exchanger was injected into the primary circuit and vaporized immediately. Then the main vessel was pressurized and the maximum pressure was about 27 bar compared with 0.5 bar in normal condition. During the accident, some of the generated vapors were dragged into the core by LBE, which may cause a reactivity insertion accident. If any positive void coefficient exists in the core, a further study on the HXLHR accident should be performed to evaluate the reactivity insertion accident.