The invention relates to safety systems for nuclear power plants (NPP), and can be used during severe accidents leading to reactor vessel and NPP containment failure. The melt cooling and confinement system includes a cone-shaped guide plate installed under the reactor vessel bottom, cantilever girder installed under the guide plate and supporting the same, core catcher installed under the cantilever girder and equipped with cooled cladding in form of a multi-layer vessel for protection of the external heat-exchange wall from dynamic, thermal and chemical impacts, and filler material for melt dilution inside the multi-layer vessel. The said multi-layer vessel has external and internal metal walls with a filler that is highly heat-conductive in relation to wall material in between, where filler material thickness h.sub.fil meets the following criterion: 1.2h.sub.ext<h.sub.fil<2.4h.sub.ext, where h.sub.ext is vessel external wall thickness.

A nuclear power plant has a nuclear reactor including a reactor pressure vessel which houses plural fuel rods containing fissile material. The nuclear power plant further has means for submerging the reactor pressure vessel in water and thereby water-cooling the reactor pressure vessel in the event of an emergency requiring cooling of the nuclear reactor. The nuclear power plant further has a primary core catcher outwardly of the reactor pressure vessel, the primary core catcher being formed of a material suitable for retaining molten corium in the event corium escapes the reactor pressure vessel The nuclear power plant further has secondary core catcher outwardly of the primary core catcher, the secondary core catcher lining a tank which is water-filled in normal use of the plant to submerge and thereby water-cool the primary core catcher. The secondary core catcher is also is formed of a material suitable for retaining molten corium in the event corium escapes the primary core catcher.

A nuclear power plant has a nuclear reactor including a reactor pressure vessel which houses plural fuel rods containing fissile material. The nuclear power plant further has means for submerging the reactor pressure vessel in water and thereby water-cooling the reactor pressure vessel in the event of an emergency requiring cooling of the nuclear reactor. The nuclear power plant further has a primary core catcher outwardly of the reactor pressure vessel, the primary core catcher being formed of a material suitable for retaining molten corium in the event corium escapes the reactor pressure vessel The nuclear power plant further has secondary core catcher outwardly of the primary core catcher, the secondary core catcher lining a tank which is water-filled in normal use of the plant to submerge and thereby water-cool the primary core catcher. The secondary core catcher is also is formed of a material suitable for retaining molten corium in the event corium escapes the primary core catcher.

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.

Systems for ensuring safety of nuclear power plants (NPPs), and can be used in severe accidents resulting in destruction of the reactor pressure vessel and containment. The systems enhance reliability of the corium localizing and cooling system of a nuclear reactor. The technical result is achieved due to prevention of the corium localizing and cooling system destruction in the junction area between the vessel and the cantilever truss by use of a membrane with bandage plates installed on the drum within the system.

Systems for ensuring safety of nuclear power plants (NPPs), and can be used in severe accidents resulting in destruction of the reactor pressure vessel and containment. The systems enhance reliability of the corium localizing and cooling system of a nuclear reactor. The technical result is achieved due to prevention of the corium localizing and cooling system destruction in the junction area between the vessel and the cantilever truss by use of a membrane with bandage plates installed on the drum within the system.

Systems ensuring safety of nuclear power plants (NPPs) used in severe accidents resulting in destruction of the reactor pressure vessel and containment. The technical result of the claimed invention is to enhance reliability of the corium localizing and cooling system of a nuclear reactor. The technical result is achieved due to use of the membrane installed between the cantilever truss and the vessel, bandage plates installed on the external and internal side of the membrane, the hydraulic gas-dynamic damper installed on the internal side of the membrane in the corium localizing and cooling system of a nuclear reactor enabling to prevent any destruction within the leak-tight junction area between the multi-layered vessel and the cantilever truss under the conditions with non-axisymmetric corium flow from the reactor pressure vessel and falling of reactor pressure vessel head fragments into the vessel at the initial stage of the corium cooling with water.

Systems ensuring safety of nuclear power plants (NPPs) used in severe accidents resulting in destruction of the reactor pressure vessel and containment. The technical result of the claimed invention is to enhance reliability of the corium localizing and cooling system of a nuclear reactor. The technical result is achieved due to use of the membrane installed between the cantilever truss and the vessel, bandage plates installed on the external and internal side of the membrane, the hydraulic gas-dynamic damper installed on the internal side of the membrane in the corium localizing and cooling system of a nuclear reactor enabling to prevent any destruction within the leak-tight junction area between the multi-layered vessel and the cantilever truss under the conditions with non-axisymmetric corium flow from the reactor pressure vessel and falling of reactor pressure vessel head fragments into the vessel at the initial stage of the corium cooling with water.

According to an embodiment, a core catcher has: a main body including: a distributor arranged on a part of a base mat in the lower dry well, a basin arranged on the distributor, cooling channels arranged on a lower surface of the basin connected to the distributor and extending in radial directions, and a riser connected to the cooling channels and extending upward; a lid connected to an upper end of the riser and covering the main body; a cooling water injection pipe open, at one end, to the suppression pool, connected at another end to the distributor; and chimney pipes connected, at one end, to the riser, another end being located above the upper end of the riser and submerged and open in the pool water.