Abstract: A flow-path forming gasket is interposed between peripheries of each adjacent ones of stacked heat transfer plates; communicating-path forming gaskets are each installed, surrounding the passage holes in each adjacent ones of the heat transfer plates alternately; and thereby a first flow path adapted to pass a high-temperature fluid, a second flow path adapted to pass a low-temperature fluid, and communicating paths adapted to cause the fluids, respectively, to flow in and out of the first and second flow paths are formed alternately on opposite sides of each heat transfer plate. A drain hole is formed in each of the heat transfer plates to discharge fluid leaking from the first flow path, the second flow path, or the communicating path. The drain hole is surrounded by gaskets isolated from the first flow path, the second flow path, or the communicating path. A leakage flow path or a leakage collector is formed by the gaskets.

Abstract: To provide a cooling system of a reactor suppression pool capable of cooling suppression pool water and improving the safety of a reactor in the case where an event surpassing a postulated initiating event occurs, or in the case where cooling of the suppression pool water by a residual heat removable system does not function. A cooling system of a reactor suppression pool according to the present invention includes a heat exchanger for cooling suppression pool water installed in the middle of a suppression pool water cooling line, operating when the temperature of the suppression pool water reaches a given temperature, performing heat exchange with the suppression pool water from a suppression pool water cleanup system suction line to cool the water, and returning the cooled suppression pool water to the suppression pool through a suppression pool water cleanup system discharge line.

Abstract: A flow-path forming gasket is interposed between peripheries of each adjacent ones of stacked heat transfer plates; communicating-path forming gaskets are each installed, surrounding the passage holes in each adjacent ones of the heat transfer plates alternately; and thereby a first flow path adapted to pass a high-temperature fluid, a second flow path adapted to pass a low-temperature fluid, and communicating paths adapted to cause the fluids, respectively, to flow in and out of the first and second flow paths are formed alternately on opposite sides of each heat transfer plate. A drain hole is formed in each of the heat transfer plates to discharge fluid leaking from the first flow path, the second flow path, or the communicating path. The drain hole is surrounded by gaskets isolated from the first flow path, the second flow path, or the communicating path. A leakage flow path or a leakage collector is formed by the gaskets.