Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.

Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.

Provided are a system and method for reducing the atmospheric release of radioactive materials caused by a severe accident. The system includes a steam generator disposed in a containment building, configured to generate steam by using heat of a coolant heated in a nuclear reactor, and connected to a turbine through a main steam line, a decontamination tank connected to the main steam line through a connection line and containing decontamination water for decontaminating the steam delivered from the steam generator and reducing atmospheric release of radioactive materials when a severe accident occurs, and a depressurizing power generation unit disposed on the connection line and configured to generate emergency power while depressurizing the steam delivered from the steam generator toward the decontamination tank when the severe accident occurs.

A nuclear reactor cooling system with passive cooling capabilities operable during a reactor shutdown event without available electric power. In one embodiment, the system includes a reactor vessel with nuclear fuel core and a steam generator fluidly coupled thereto. Primary coolant circulates in a flow loop between the reactor vessel and steam generator to heat secondary coolant in the steam generator producing steam. The steam flows to a heat exchanger containing an inventory of cooling water in which a submerged tube bundle is immersed. The steam is condensed in the heat exchanger and returned to the steam generator forming a closed flow loop in which the secondary coolant flow is driven by natural gravity via changes in density from the heating and cooling cycles. In other embodiments, the cooling system is configured to extract and cool the primary coolant directly using the submerged tube bundle heat exchanger.

The invention relates to the nuclear energy field, including pressurized water reactor containment internal passive heat removal systems. The invention increases heat removal efficiency, flow stability in the circuit, and system reliability. The system has at least one cooling water circulation circuit comprising a heat exchanger inside the containment and including an upper and lower header interconnected by heat-exchange tubes, a riser pipeline and a downtake pipeline connected to the heat exchanger, a cooling water supply tank above the heat exchanger outside the containment and connected to the downtake pipeline, a steam relief valve connected to the riser pipeline and located in the water supply tank and hydraulically connected to the latter. The upper and lower header of the heat exchanger are divided into heat exchange tube sections on the assumption that: L/D20, L being the header section length, D being the header bore.

The invention relates to the nuclear energy field, including pressurized water reactor containment internal passive heat removal systems. The invention increases heat removal efficiency, flow stability in the circuit, and system reliability. The system has at least one cooling water circulation circuit comprising a heat exchanger inside the containment and including an upper and lower header interconnected by heat-exchange tubes, a riser pipeline and a downtake pipeline connected to the heat exchanger, a cooling water supply tank above the heat exchanger outside the containment and connected to the downtake pipeline, a steam relief valve connected to the riser pipeline and located in the water supply tank and hydraulically connected to the latter. The upper and lower header of the heat exchanger are divided into heat exchange tube sections on the assumption that: L/D20, L being the header section length, D being the header bore.

The present invention discloses a passive cooling system of a containment building, to which a plate-type heat exchanger is applied. A passive cooling system of a containment building comprises: a containment building; a plate-type heat exchanger provided to at least one of the inside and the outside of the containment building and comprising channels respectively provided to the both sides of a plate so as to be arranged dividedly from each other such that the plate-type heat exchanger carries out mutual heat exchange between the internal atmosphere of the containment building and a heat exchange fluid while maintaining a pressure boundary; and a pipe connected to the plate-type heat exchanger by penetrating the containment building so as to form the path of the internal atmosphere of the containment building or the heat exchange fluid.

The present invention discloses a passive cooling system of a containment building, to which a plate-type heat exchanger is applied. A passive cooling system of a containment building comprises: a containment building; a plate-type heat exchanger provided to at least one of the inside and the outside of the containment building and comprising channels respectively provided to the both sides of a plate so as to be arranged dividedly from each other such that the plate-type heat exchanger carries out mutual heat exchange between the internal atmosphere of the containment building and a heat exchange fluid while maintaining a pressure boundary; and a pipe connected to the plate-type heat exchanger by penetrating the containment building so as to form the path of the internal atmosphere of the containment building or the heat exchange fluid.

Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.

Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.