Abstract: According to an embodiment, a nuclear reactor containment vessel has: a primary reactor containment vessel which contains a nuclear pressure vessel; a secondary reactor containment vessel and which is disposed outside the primary reactor containment vessel which has the pressure resistant properties and the leak-tightness which are equivalent to those of the primary reactor containment vessel; an air bag which is disposed within the secondary reactor containment vessel and which, when a failure occurs in primary reactor containment vessel, expands while receiving and encapsulating a high pressure gas discharged from the inside of the primary reactor containment vessel; and a gas phase vent pipe which connects the primary reactor containment vessel and the air bag.

Abstract: According to an embodiment, a pressurized water reactor plant has a primary system which includes: a reactor vessel for housing a reactor core which is cooled by a primary coolant, a single steam generator, a hot leg pipe for connecting the reactor vessel and the steam generator, cold leg pipes, at least two primary coolant pumps, and a pressurizer for pressurizing the primary coolant pressure boundary in which the primary coolant flows. The plant also has: a passive cooling and depressurization system which is a primary depressurization means for equalizing the primary system pressure to the secondary system pressure at the time of a tube rupture accident of the steam generator, and a reactor containment vessel containing the primary system and cooling the primary system by air cooling. Thus, a compact pressurized water rector with high economic efficiency, safety, and reliability can be provided.

Abstract: A drain sump of a reactor containment vessel having a containment vessel floor down below a reactor pressure vessel, and includes a heat-proof sump cover and two or more drain flow paths. The drain sump is arranged inside the containment vessel floor. The heat-proof sump cover has a thickness, and covers an upper part of the drain sump. The thickness allows a top surface of the sump cover to lie in the same surface as a top surface of the containment vessel floor. The drain flow paths pass through the sump cover in a thickness direction to flow water therethrough and solidify a molten corium therein. The molten corium is produced in the unlikely event of a severe accident.

Abstract: According to an embodiment, a nuclear reactor containment vessel has: a primary reactor containment vessel which contains a nuclear pressure vessel; a secondary reactor containment vessel and which is disposed outside the primary reactor containment vessel which has the pressure resistant properties and the leak-tightness which are equivalent to those of the primary reactor containment vessel; an air bag which is disposed within the secondary reactor containment vessel and which, when a failure occurs in primary reactor containment vessel, expands while receiving and encapsulating a high pressure gas discharged from the inside of the primary reactor containment vessel; and a gas phase vent pipe which connects the primary reactor containment vessel and the air bag.

Abstract: According to an embodiment, a pressurized water reactor plant has a primary system which includes: a reactor vessel for housing a reactor core which is cooled by a primary coolant, a single steam generator, a hot leg pipe for connecting the reactor vessel and the steam generator, cold leg pipes, at least two primary coolant pumps, and a pressurizer for pressurizing the primary coolant pressure boundary in which the primary coolant flows. The plant also has: a passive cooling and depressurization system which is a primary depressurization means for equalizing the primary system pressure to the secondary system pressure at the time of a tube rupture accident of the steam generator, and a reactor containment vessel containing the primary system and cooling the primary system by air cooling. Thus, a compact pressurized water rector with high economic efficiency, safety, and reliability can be provided.

Abstract: A drain sump of a reactor containment vessel having a containment vessel floor down below a reactor pressure vessel, and includes a heat-proof sump cover and two or more drain flow paths. The drain sump is arranged inside the containment vessel floor. The heat-proof sump cover has a thickness, and covers an upper part of the drain sump. The thickness allows a top surface of the sump cover to lie in the same surface as a top surface of the containment vessel floor. The drain flow paths pass through the sump cover in a thickness direction to flow water therethrough and solidify a molten corium therein. The molten corium is produced in the unlikely event of a severe accident.

Abstract: A pressure suppression and decontamination apparatus for a reactor container which is provided with a reactor pressure vessel containing nuclear core fuel and forms a dry well space including, a dry well cooling unit for cooling a gas in the dry well space and for producing a condensate of the gas, a circulation device for leading the gas in the dry well space to the dry well cooling unit, and a sprinkling device for sprinkling the condensate in the dry well space.

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: There is provided an optical pickup apparatus which is small in size and excellent in releasing action of heat generated inside the apparatus. An optical pickup apparatus includes semiconductor lasers as light sources for emitting light, a laser driver for controlling light emitting operations of the semiconductor lasers, a first housing in which the laser driver is housed, and a second housing in which the semiconductor lasers are housed. The first housing 31 and the second housing are separately formed and connected to each other so as to have a void portion therebetween, which penetrates the first housing and the second housing in thickness directions thereof. The laser driver and the semiconductor lasers are disposed so as to be adjacent to each other via the void portion, and housed in the housing.

Abstract: Light from a light source is led to a condensing lens by a light leading unit and is condensed onto an optical recording medium by the condensing lens. Light reflected from the optical recording medium is led to a light sensing device through a spot adjustment lens facing the light sensing device. Between the spot adjustment lens and the light sensing device, a cylindrical dustproof member is provided. The full periphery of an optical path extending between the spot adjustment lens and the light sensing device is covered with the dustproof member. It can prevent intrusion of a foreign matter such as dusts into the optical path extending between the spot adjustment lens and the light sensing device.

Abstract: Light from a light source is led to a condensing lens by a light leading unit and is condensed onto an optical recording medium by the condensing lens. Light reflected from the optical recording medium is led to a light sensing device through a spot adjustment lens facing the light sensing device. Between the spot adjustment lens and the light sensing device, a cylindrical dustproof member is provided. The full periphery of an optical path extending between the spot adjustment lens and the light sensing device is covered with the dustproof member. It can prevent intrusion of a foreign matter such as dusts into the optical path extending between the spot adjustment lens and the light sensing device.

Abstract: There is provided an optical pickup apparatus which is small in size and excellent in releasing action of heat generated inside the apparatus. An optical pickup apparatus includes semiconductor lasers as light sources for emitting light, a laser driver for controlling light emitting operations of, the semiconductor lasers, a first housing in which the laser driver is housed, and a second housing in which the semiconductor lasers are housed. The first housing 31 and the second housing are separately formed and connected to each other so as to have a void portion therebetween, which penetrates the first housing and the second housing in thickness directions thereof. The laser driver and the semiconductor lasers are disposed so as to be adjacent to each other via the void portion, and housed in the housing.

Abstract: A nuclear reactor containment vessel cooling equipment has: a dry well cooler casing in a containment vessel, having an opening at its top and a shutter at its lower part; a heat transfer tube arranged at an upper part in the dry well cooler casing; a forced cooling water circulation system for feeding cooling water from outside of the containment vessel into the heat transfer tube by a pump; a blower for mobilizing gas around the heat transfer tube; an external pool container arranged outside the containment vessel and above the heat transfer tube and containing cooling water; and a gravity-driven cooling system to supply cooling water in the external pool container into the heat transfer tube, utilizing gravity.

Abstract: Light from a light source is led to a condensing lens by a light leading unit and is condensed onto an optical recording medium by the condensing lens. Light reflected from the optical recording medium is led to a light sensing device through a spot adjustment lens facing the light sensing device. Between the spot adjustment lens and the light sensing device, a cylindrical dustproof member is provided. The full periphery of an optical path extending between the spot adjustment lens and the light sensing device is covered with the dustproof member. It can prevent intrusion of a foreign matter such as dusts into the optical path extending between the spot adjustment lens and the light sensing device.

Abstract: A pressure suppression and decontamination apparatus for a reactor container which is provided with a reactor pressure vessel containing nuclear core fuel and forms a dry well space including, a dry well cooling unit for cooling a gas in the dry well space and for producing a condensate of the gas, a circulation device for leading the gas in the dry well space to the dry well cooling unit, and a sprinkling device for sprinkling the condensate in the dry well space.

Abstract: Light from a light source is led to a condensing lens by a light leading unit and is condensed onto an optical recording medium by the condensing lens. Light reflected from the optical recording medium is led to a light sensing device through a spot adjustment lens facing the light sensing device. Between the spot adjustment lens and the light sensing device, a cylindrical dustproof member is provided. The full periphery of an optical path extending between the spot adjustment lens and the light sensing device is covered with the dustproof member. It can prevent intrusion of a foreign matter such as dusts into the optical path extending between the spot adjustment lens and the light sensing device.