Patent ID: 6944255

Claim:
A nuclear reactor comprising: a double vessel accommodating a reactor core therein, the double vessel including a reactor vessel as an inner vessel of the double vessel, and an outer vessel of the double vessel which is outward of the reactor vessel; a primary coolant stored in the reactor vessel and adapted to be heated by the reactor core for creating convection of the primary coolant in the reactor vessel; a first heat transfer tube in the reactor vessel and in contact with the primary coolant; a secondary coolant stored between the outer vessel and the reactor vessel of the double vessel with first means for supplying the secondary coolant from outside the reactor vessel to the first heat transfer tube for cooling the primary coolant and for leading the secondary coolant to the outside the reactor vessel; a second heat transfer tube between the outer vessel and the reactor vessel of the double vessel and in contact with the secondary coolant; and a tertiary coolant with second means for supplying the tertiary coolant from outside the double vessel to the second heat transfer tube for cooling the secondary coolant and for leading the tertiary coolant to the outside of the double vessel; and wherein the first heat transfer tube is arranged on an inner surface of the reactor vessel and is connected to an upper header and to a lower header, the upper and lower headers being open to the outside of the reactor vessel, and the primary coolant and the secondary coolant being liquid metal.