The residual heat removal system of molten salt reactor designed by ORNL

using molten salt as fuel and draining the fuel into fuel drain tank after shutdown of the reactor

removes the decay heat by the circulation of water through the bayonet cooling thimbles in the fuel drain tank.According to structural features of the bayonet cooling thimbles in ORNL 10 MW molten salt reactor experiment(MSRE)

this paper presents the analytical results of the influence of the width of gas gap and the width of steam riser on the heat removal ability and the natural circulation of the cooling water

etc.The analysis results show that

when the width of gas gap range from 3.1 mm to 5.1 mm

the change of heat dissipation power and natural circulation flow rate are both less than 5%;when the width of steam riser changes from 3.6 mm to 5.1 mm

the flow mass of the natural circulation change from 1.9 kg/s to 4.79 kg/s

with a slightly effect on the heat transfer efficiency of the system.