| 摘要 |
PROBLEM TO BE SOLVED: To provide cooling facilities of a reactor pressure vessel capable of cooling a reactor pressure vessel with a natural return current when a severe accident occurs in a reactor.SOLUTION: A wall member 2 is fixed separately by a gap G from a lower part of a reactor pressure vessel 1. A coolant water system is provided so that coolant water can flow into and out of the gap G. The coolant water system comprises: a condenser 9 arranged in a position higher than an outlet of coolant water; and an on-off valve 13 switchable between a blocking state and a flowing state of coolant water flowing down from the condenser 9. By switching the on-off valve 13 from its closing state to its opening state when a severe accident occurs, a coolant water system is formed in a natural return current by buoyant force of vapor and water head pressure of coolant water. |
