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.

A safety method for a reactor including a primary circuit in which a water-based primary fluid is intended to circulate, and a secondary circuit, in which a water-based secondary fluid is intended to circulate, the secondary circuit being hydraulically isolated from the primary circuit and including a steam generator is provided. In the event of a meltdown of the core of the reactor with the formation of a corium bath in a bottom of the vessel: in response to the detection of the formation of a liquid metallic layer at the surface of the corium bath: the method provides for setting the secondary circuit in fluidic communication with the primary circuit so that the secondary fluid follows the primary circuit to flow inside the vessel over the liquid metallic layer of the corium bath.

A safety method for a reactor including a primary circuit in which a water-based primary fluid is intended to circulate, and a secondary circuit, in which a water-based secondary fluid is intended to circulate, the secondary circuit being hydraulically isolated from the primary circuit and including a steam generator is provided. In the event of a meltdown of the core of the reactor with the formation of a corium bath in a bottom of the vessel: in response to the detection of the formation of a liquid metallic layer at the surface of the corium bath: the method provides for setting the secondary circuit in fluidic communication with the primary circuit so that the secondary fluid follows the primary circuit to flow inside the vessel over the liquid metallic layer of the corium bath.

An in-vessel cooling and power generation system according to the present disclosure may include a small scale reactor vessel, a heat exchange section provided inside the reactor vessel, and formed to supply supercritical fluid to receive heat from a reactor coolant system in the reactor vessel, an electric power production section comprising a supercritical turbine formed to produce electric energy using the energy of the supercritical fluid whose temperature has increased while receiving heat from the reactor coolant system, a cooling section configured to exchange heat with the supercritical fluid discharged after driving the supercritical turbine to shrink a volume of the supercritical fluid, wherein the supercritical fluid that has received heat from the reactor coolant system in the heat exchange section is formed to circulate through the electric power production section, and the cooling section.

An in-vessel cooling and power generation system according to the present disclosure may include a small scale reactor vessel, a heat exchange section provided inside the reactor vessel, and formed to supply supercritical fluid to receive heat from a reactor coolant system in the reactor vessel, an electric power production section comprising a supercritical turbine formed to produce electric energy using the energy of the supercritical fluid whose temperature has increased while receiving heat from the reactor coolant system, a cooling section configured to exchange heat with the supercritical fluid discharged after driving the supercritical turbine to shrink a volume of the supercritical fluid, wherein the supercritical fluid that has received heat from the reactor coolant system in the heat exchange section is formed to circulate through the electric power production section, and the cooling section.

The invention relates to safety systems for nuclear power plants (NPP), and can be used in the event of 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 contains external and internal metal walls with filler of poorly heat-conductive in relation to the wall material in between. Filler thickness h.sub.fil shall meet the following requirement: 0.8 h.sub.ext<h.sub.fil<1.6 h.sub.ext, where h.sub.ext is vessel external wall thickness.

The invention relates to safety systems for nuclear power plants (NPP), and can be used in the event of 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 contains external and internal metal walls with filler of poorly heat-conductive in relation to the wall material in between. Filler thickness h.sub.fil shall meet the following requirement: 0.8 h.sub.ext<h.sub.fil<1.6 h.sub.ext, where h.sub.ext is vessel external wall thickness.

The invention relates to safety systems for nuclear power plants (NPP), and can be used in the event of 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 contains internal and external metal layers with an intermediate layer in the form of a non-metal filler located in between. Bearing ribs are installed between the internal and external layers at an azimuth pitch (Spitch) that meets the following criterion: dext/15<spitch<dext/5, where dext is external diameter of the vessel.

The invention relates to safety systems for nuclear power plants (NPP), and can be used in the event of 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 contains internal and external metal layers with an intermediate layer in the form of a non-metal filler located in between. Bearing ribs are installed between the internal and external layers at an azimuth pitch (Spitch) that meets the following criterion: dext/15<spitch<dext/5, where dext is external diameter of the vessel.

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.