Water Ingress Accident of 250 MW Pebble-Bed Modular High-Temperature Gas-Cooled Reactor

Based on the preliminary design of 250 MW Pebble-bed Modular High-Temperature Gas-cooled Reactor(HTR-PM),the design basis accident(DBA) of two-area broken of single heat-exchange tube was analyzed by using TINTE,a special system analysis program for high-temperature gas-cooled reactors.Some safety relevant concerns,such as the fuel temperature and primary loop pressure,the graphite corrosion mass,the explosive gas releasing amount,as well as the natural convection influence under the condition of the failure of the blower baffle shut down,were studied.The calculation results indicate that,in the DBA of two-area broken of single heat-exchange tube of a steam generator and the consequent maximal water ingress amount of 600 kg,the maximal fuel temperature keeps far below the design limit 1 620 ℃.The results also show that the slight amount of graphite corrosion will not damage the reactor structure and the fuel element,and there is no potential explosive risk caused by the opening of the safety valve.