Reactor container

A pressure suppression chamber is divided by a wall into an inner circumferential portion on the side of an exit port and an outer circumferential portion in adjacent with an outer circumferential pool, and the outer circumferential portion and the inner circumferential portion are in communication with each other. If a great amount of steams at a high temperature and a high pressure in a reactor pressure vessel should be leaked in a dry well, the leaked steams are flown into the inner circumferential side of a pressure suppression pool together with incondensible gases in the dry well. The steams are condensed there to elevate the temperature of the pressure suppression pool, while incondensible gases are accumulated in a wet well on the inner circumferential side. This can increase the partial pressure of the incondensible gas higher than that in the wet well on the outer circumferential side. The water level in the inner circumferential portion is reduced due to the pressure difference by the effect of the communication pipe to elevate, on the contrary, the water level in the outer circumferential portion. As a result, the area for thermal conduction to the outer circumferential pool is increased and heat dissipation characteristics are improved, to lower the pressure. After-heat can be eliminated efficiently and the size of the reactor container can be reduced without using dynamic equipments. (N.H.)