Configurations of molten fuel salt reactors are described that allow for active cooling of the containment vessel of the reactor by the primary coolant. Furthermore, naturally circulating reactor configurations are described in which the reactor cores are substantially frustum-shaped so that the thermal center of the reactor core is below the outlet of the primary heat exchangers. Heat exchanger configurations are described in which welded components are distanced from the reactor core to reduce the damage caused by neutron flux from the reactor. Radial loop reactor configurations are also described.

Configurations of molten fuel salt reactors are described that allow for active cooling of the containment vessel of the reactor by the primary coolant. Furthermore, naturally circulating reactor configurations are described in which the reactor cores are substantially frustum-shaped so that the thermal center of the reactor core is below the outlet of the primary heat exchangers. Heat exchanger configurations are described in which welded components are distanced from the reactor core to reduce the damage caused by neutron flux from the reactor. Radial loop reactor configurations are also described.

A safety injection device includes, a cooling water storage section accommodating cooling water injected into the reactor coolant system, a power producing section producing power with steam discharged from the reactor coolant system in case of an accident, a steam supply pipe transmitting steam discharged from the reactor coolant system to the power producing section, a steam discharge pipe discharging steam used to drive the power producing section and a safety injection line supplying cooling water accommodated in the cooling water storage section to the inside of the reactor coolant system. In addition, cooling water accommodated in the cooling water storage section is supplied to the inside of the reactor coolant system, based on the power produced by the power producing section, through a cooling water inlet pipe connecting the cooling water storage section and the power producing section.

A safety injection device includes, a cooling water storage section accommodating cooling water injected into the reactor coolant system, a power producing section producing power with steam discharged from the reactor coolant system in case of an accident, a steam supply pipe transmitting steam discharged from the reactor coolant system to the power producing section, a steam discharge pipe discharging steam used to drive the power producing section and a safety injection line supplying cooling water accommodated in the cooling water storage section to the inside of the reactor coolant system. In addition, cooling water accommodated in the cooling water storage section is supplied to the inside of the reactor coolant system, based on the power produced by the power producing section, through a cooling water inlet pipe connecting the cooling water storage section and the power producing section.

A pump assisted heat pipe may combine the low mass flow rate required of latent heat pipe transfer loops with a hermetically sealed pump to overcome the typical heat pipe capillary limit. This may result in a device with substantially higher heat transfer capacity over conventional pumped single-phase loops, heat pipes, loop heat pipes, and capillary pumped loops with very modest power requirements to operate. Further, one or more embodiments overcome the gravitation limitations in the conventional heat pipe configuration, e.g., when the heat addition zone is above the heat rejection zone, the capillary forces are required to transfer the liquid from the heat rejection zone to the heat addition zone against gravity.

A pump assisted heat pipe may combine the low mass flow rate required of latent heat pipe transfer loops with a hermetically sealed pump to overcome the typical heat pipe capillary limit. This may result in a device with substantially higher heat transfer capacity over conventional pumped single-phase loops, heat pipes, loop heat pipes, and capillary pumped loops with very modest power requirements to operate. Further, one or more embodiments overcome the gravitation limitations in the conventional heat pipe configuration, e.g., when the heat addition zone is above the heat rejection zone, the capillary forces are required to transfer the liquid from the heat rejection zone to the heat addition zone against gravity.

Proposed is a passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system allowing a passive condensation tank to include an inner wall and an outer wall and a cooling means to be interposed between the inner wall and the outer wall, thereby suppressing the increase in the temperature of the heat exchange water in a condensation process in the passive condensation tank. To this end, proposed is the passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system including: a passive condensation tank having a water storage space to store heat-exchange water; and a condenser arranged to be immersed in the heat-exchange water in the passive condensation tank, wherein the passive condensation tank includes the outer and inner walls providing the water storage space and a cooling means interposed between the walls for absorbing heat of the heat-exchange water.

Proposed is a passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system allowing a passive condensation tank to include an inner wall and an outer wall and a cooling means to be interposed between the inner wall and the outer wall, thereby suppressing the increase in the temperature of the heat exchange water in a condensation process in the passive condensation tank. To this end, proposed is the passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system including: a passive condensation tank having a water storage space to store heat-exchange water; and a condenser arranged to be immersed in the heat-exchange water in the passive condensation tank, wherein the passive condensation tank includes the outer and inner walls providing the water storage space and a cooling means interposed between the walls for absorbing heat of the heat-exchange water.

A nuclear power generation system includes a nuclear reactor that includes a reactor core fuel and a nuclear reactor vessel, the nuclear reactor vessel covering a surrounding of the reactor core fuel, shielding a space in which the reactor core fuel is present, and shielding radioactive rays; a heat conductive portion that is disposed in at least a part of the nuclear reactor vessel to transfer heat inside the nuclear reactor vessel to an outside by solid heat conduction; a heat exchanger that performs heat exchange between the heat conductive portion and a refrigerant; a refrigerant circulation unit that circulates the refrigerant passing through the heat exchanger; a turbine that is rotated by the refrigerant circulated by the refrigerant circulation unit; and a generator that rotates integrally with the turbine.

Alternative designs for a modular test reactor are presented. In one aspect, a molten fuel salt nuclear reactor includes a vessel defining a reactor volume, the vessel being open-topped and otherwise having no penetrations. A neutron reflector is provided within the vessel and displacing at least some of the reactor volume, the neutron reflector defining a reactor core volume. A plurality of heat exchangers are contained within the vessel above the neutron reflector. A flow guide assembly is provided within the neutron reflector that includes a draft tube draft tube separating a central portion of the reactor core volume from an annular downcomer duct. Fuel salt circulates from the reactor core volume, through the heat exchangers, into the downcomer duct and then back into the reactor core volume.