Combustion device for hydrogen contained in atmosphere of reactor container

A helical-shaped heater of a combustion device is protruded horizontally from a terminal member secured to a structural member such as a building wall inside the reactor container. A plurality of bent rectangular outer cover members, namely, C-shape cross sectioned baffles are disposed in an annular shape each at an interval in the circumferential direction. The baffle having a C-shaped cross section is concave radially inwardly and turn-back portions are formed on both sides. The turn-back portion acts as a gutter for flowing dropped spray water of emergency cooling water. Bent rectangular inner cover members, namely, C-shape cross sectioned baffles are formed being opposed to each gap between adjacent outer C-shape cross sectioned baffles. The inner C-shape cross sectioned baffles are concave radially outwardly in the cross section being reversed to the outer C-shape cross sectioned baffles, and turned back portions are formed on both sides. (I.N.)