Abstract: A core catcher includes a holding surface that catches and holds corium and that introduces a surrounding coolant into the core catcher and cool the core catcher by heat exchange with the introduced coolant. The holding surface and the cooling unit are constructed by arranging blocks which each include a polyhedron having at least one pair of parallel surfaces and having an opening portion formed in a surface located in a lateral direction when a first surface that is one of the parallel surfaces is arranged as a bottom surface and are configured such that the polyhedrons communicate with each other via the opening portion when the polyhedrons are arranged adjacent in the lateral direction. The core catcher can achieve easier installation of the blocks without an increase in installation cost.

Abstract: According to an embodiment, a molten-core retention structure comprises the following inside a reactor vessel that contains a reactor core: a bottom support plate, in which vertically penetrating flow holes are formed, that is provided beneath the core and supports the core; a bottom support plate support that is affixed to the reactor vessel and supports the bottom support plate; a thermally insulating spacer; a reticulated heat path that is affixed to the bottom support plate support with the thermally insulating spacer interposed therebetween and contacts the bottom support plate; and vertical heat paths that extend downwards from the reticulated heat path. The reticulated heat path and the vertical heat paths have higher coefficients of thermal conductivity than the thermally insulating spacer.

Abstract: Core debris generated during a molten reactor core in a reactor containment vessel penetrating the reactor containment vessel is configured to be caught by a core catcher located beneath the reactor containment vessel which has a main body having first stage cooling water channels and second stage surrounded by cooling fins extending radially. The number of the second stage cooling channels is larger than that of the first stage cooling channels. Cooling water is supplied from a cooling water injection opening and distributed to the first cooling water channels at a distributor. An intermediate header is formed between the first and the second cooling water channels, and the cooling water is distributed to the second cooling water channels uniformly.

Abstract: An embodiment of a nuclear power plant has: a reactor vessel containing a core; a reactor containment vessel containing the reactor vessel; and a radiation heat reflecting member disposed at a portion below the reactor vessel inside the reactor containment vessel. The radiation heat reflecting member may block radiation heat, which is emitted toward a side wall surface of the reactor containment vessel from the core that has been put in a molten state by an accident and flowed downward from the reactor vessel to be accumulated at a lower portion of the reactor containment vessel. The radiation heat reflecting member may block radiation heat, which is emitted toward a supporting structure supporting devices disposed inside the reactor containment vessel.

Abstract: A core catcher includes a holding surface that catches and holds corium and that introduces a coolant with which surroundings of the core catcher are filled into the core catcher and cool a whole of the core catcher by heat exchange with the introduced coolant. The holding surface and the cooling unit are constructed by arranging blocks which each include a polyhedron having at least one pair of parallel surfaces and having opening portion formed in a surface located in a lateral direction when a first surface that is one of the parallel surfaces is arranged as a bottom surface and are configured such that the polyhedrons communicate with each other via the opening portion when the polyhedrons are arranged adjacent in the lateral direction. The core catcher, as described above, can be achieved easier installation of the blocks without an increase in installation cost.

Abstract: A reactor containment vessel cooling technology for preventing the cooling capability and structural integrity of a reactor containment vessel cooling system from decreasing by lowering the temperature of water vapor and gases acquired by the reactor containment vessel cooling system is provided. Based on the technology, the present invention provides a reactor containment vessel cooling system that acquires water vapor in a reactor containment vessel by using water vapor pressure in the vessel as a drive force, condenses the acquired water vapor into condensate, and cools the reactor containment vessel with the condensate.

Abstract: A water leak detection floor transversally suspended by a pedestal side wall is installed between a reactor pressure vessel and a molten core holding apparatus. If a water leak occurs at the reactor pressure vessel, the water leak detection floor receives and detects the leak water. In a core meltdown accident, corium melts and penetrates the water leak detection floor and deposits on the molten core holding apparatus.

Abstract: Core debris generated during a molten reactor core in a reactor containment vessel penetrating the reactor containment vessel is configured to be caught by a core catcher located beneath the reactor containment vessel which has a main body having first stage cooling water channels and second stage surrounded by cooling fins extending radially. The number of the second stage cooling channels is larger than that of the first stage cooling channels. Cooling water is supplied from a cooling water injection opening and distributed to the first cooling water channels at a distributor. An intermediate header is formed between the first and the second cooling water channels, and the cooling water is distributed to the second cooling water channels uniformly.

Abstract: A hydrogen removing apparatus removes without fail the hydrogen gas generated within a nuclear reactor-housing vessel by a metal-water reaction so as to suppress the pressure elevation within the nuclear reactor-housing vessel. The hydrogen removing apparatus comprises a reactor provided with at least two openings through which the outer atmosphere is introduced into the reactor and a catalyst bed arranged within the reactor and loaded with a catalyst for promoting the ammonia synthesizing reaction between a nitrogen gas and a hydrogen gas.

Abstract: An apparatus for removing flammable gas is started only when a concentration change in the flammable gas in a primary containment vessel is detected, so that the decrease in activity of a catalyst due to a catalyst poison is prevented. This apparatus has a catalytic recombining apparatus equipped with a catalyst 1 for reacting the flammable gas, a case 2 that houses the catalyst, and lids 4a and 4b installed at openings 3a and 3b of the case 2. Adhesive parts 5a and 5b which adhere the lids 4a and 4b and the case 2 is melted at high temperatures, and heating elements 6a and 6b composed of an oxidizing catalyst of hydrogen is installed in contact with the adhesive parts 5a and 5b. Thus, the lids are not only closed under normal conditions but opened when the adhesive parts 5a and 5b being melted along with the temperature increase in the surrounding atmosphere.

Abstract: An interactive recording/reproducing medium including: image data; image reproduction control data which defines an operation instruction received from operation input apparatus and a reproduction procedure for the image data in correlation with each other, the operation input apparatus performing a reproducing operation for the image data in an interactive manner; image related data related to the contents of the image data; and relation defining information which defines the relation between the image related data and the image data. More particularly, an interactive recording/reproducing system which is interactively responsive to operations made by a user, which defines information such as text data (e.g., ASCII text) in association with an image and reproduces the text data simultaneously with reproduction of the image. An optical disk medium comprises a Video-CD recording area for recording image data (e.g.