PASSIVE COOLING SYSTEM FOR LIQUID-METAL COOLED NUCLEAR REACTOR HAVING RESERVED COOLING FLOW PATH

摘要

PURPOSE: To obtain a passive auxiliary safety cooling system for removing the residual heat generated by fuel disintegration during shutdown of a liquid-metal cooled fission reactor or the heat generated on the occasion of an accident by a construction wherein a secondary passive safety cooling system surrounding a primary passive safety cooling system is provided outside this system. CONSTITUTION: A reserved safety cooling passage 58 is separated from a primary auxiliary safety cooling passage 56 and partial spaces 62 and 64 of cooling air and ducts 68 and 66 are still open when isolation valves 52 and 54 are closed. The heat of a nuclear reactor is removed by the cooling passage 58 at all times, including a state of normal operation of the reactor and a state of disintegration heat removing operation of the cooling passage 56. However, the removal of the heat is increased remarkably by the cooling passage 58 when a protective vessel 24 is filled partly with a metal coolant of high temperature subsequently to a phenomenon of double leak of vessels 12 and 20 and when the level 80 of the liquid-metal coolant in the normal operation in the vessel 12 lowers to a double vessel leak level 82 in the vessel 12. Thereby the temperature of the liquid-metal coolant of maximum bulk can be maintained at the design limit or below for preventing destructive or dangerous results.