Emergency core cooling method

Purpose: To eliminate the use of driving equipments such as pumps or valves and improve the cooling effect. Method: Referring to a case of applied to a BWR type reactor for example, a partition wall is disposed at a lower portion of a reactor container to define a water storing portion by the partition wall and the lower portion of the container, and coolants are filled to the inside thereof. Communication pipes are disposed for connecting the lower portion of the water storing portion and the reactor core. In the simple structure as described above, the coolants in the upper portion of the water storing portion is maintained at a high temperature by the heat of the primary coolants, while the coolants in the lower portion are kept at a lower temperature by the heat dissipation from the reactor vessel. Now upon occurrence of reactor accidents, if the pressure in the reactor vessel is lowered, high temperature coolants in the water storing portion are boiled under a reduced pressure and their volume is expanded by the boiling and the low temperature coolants are supplied in the reactor core by the volume expanding force. Since the volume expanding force is used as a driving source for supplying the coolant to reactor core, driving equipments such as pumps are no more necessary. (Ikeda, J.)