Abstract: The present disclosure relates to an apparatus for detecting nuclear reactor coolant leaks that is capable of maintaining radiation detection reliability and the integrity of a radiation detector from high-dose background radiation inside a nuclear reactor when a coolant leaks from the primary coolant system of the nuclear reactor. The apparatus of the present disclosure includes a shield having an internal space into which sample air containing a coolant leaking from a primary coolant system pipe of a nuclear reactor is introduced, and configured to close the exposed internal space or expand the internal space through detachable coupling; a first sensor disposed in the internal space to obtain a radiation measurement signal from the sample air; and a discriminator for determining whether a coolant is leaking based on the radiation measurement signal. This work was supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government (MOTIE) (No.

Abstract: A sensor tube according to the present invention comprises: a tubular body for connecting two connection pipes to each other, wherein the two connection pipes are connected to a humidity sensor, so that the connection pipes transfer steam to the humidity sensor by using circulating air or air discharged from the humidity sensor flow in the connection pipes; and a cover surrounding at least a part of the outer surface of the body to prevent foreign substances having a predetermined size or larger from passing, wherein the body is formed as a porous sintered body which allows stream to be introduced from the outside of the body into the body and be transferred by the circulating air.

Abstract: A sensor tube according to the present disclosure includes a body including a body extension having opposite ends connected to measurement air connection pipes and an opening, the measurement air connecting pipes being connected to a humidity sensor to deliver moisture to the humidity sensor using measurement air or allow the measurement air released from the humidity sensor to flow therethrough, and the opening being formed in the body extension to cause an interior space of the body extension and the outside to be in communication with each other such that the moisture is introduced into the interior space of the body extension from the outside through the opening, and an opening/closing part that selectively opens or closes the opening by being operated by a difference in pressure between the interior space of the body extension and the outside.

Abstract: A semiconductor device includes: a fin-type active region protruding from a substrate and extending in a first direction; at least one nano-sheet spaced apart from an upper surface of the fin-type active region and facing the upper surface of the fin-type active region, the at least one nano-sheet having a channel region; a gate extending on the fin-type active region in a second direction crossing the first direction and surrounding at least a portion of the at least one nano-sheet; a source/drain region on the fin-type active region on both sides of the at least one nano-sheet; and a source/drain protection layer on a sidewall of the at least one nano-sheet and between the source/drain region and the at least one nano-sheet.

Abstract: A semiconductor device includes: a fin-type active region protruding from a substrate and extending in a first direction; at least one nano-sheet spaced apart from an upper surface of the fin-type active region and facing the upper surface of the fin-type active region, the at least one nano-sheet having a channel region; a gate extending on the fin-type active region in a second direction crossing the first direction and surrounding at least a portion of the at least one nano-sheet; a source/drain region on the fin-type active region on both sides of the at least one nano-sheet; and a source/drain protection layer on a sidewall of the at least one nano-sheet and between the source/drain region and the at least one nano-sheet.

Abstract: Disclosed herein is a water-air combined passive feed water cooling apparatus including a water cooling heat exchanger connected to the inside of a containment building to cool down heat of a steam generator using a water cooling method, a cooling tank including the water cooling heat exchanger therein and storing cooling water condensing main steam generated by the steam generator, an evaporative steam pipe connected to the cooling tank, the evaporative steam pipe, into which steam of the cooling water generated by the water cooling heat exchanger in the cooling tank flows, an air cooling heat exchanger connected to the evaporative steam pipe and cooling down and liquefying the steam flowing into the evaporative steam pipe, and a condensed water collecting pipe for refilling the cooling tank with the steam liquefied by the air cooling heat exchanger.

Abstract: A hybrid safety injection tank system. The system is pressurized with a safety valve of a pressurizer, which functions as a low pressure safety injection tank and as a high pressure core makeup tank of a nuclear reactor emergency core cooling system. The safety valve is configured to be automatically operated in response to a pressure difference and is installed on a pressure equalization pipe that can realize pressure equalization between the low pressure safety injection tank and the high pressure pressurizer in the event of the nuclear power plant station blackout and power outage.

Abstract: Provided is a passive containment air cooling device with an isolated pressure boundary, including a heat exchanger positioned inside and outside a containment, penetrating through an outer wall of the containment to be connected to the containment through a pipe and thus form a closed loop, and including a coolant, an air induction duct circulating air outside the heat exchanger, and a cooled air exhaust unit formed in the air induction duct to increase cooling efficiency of the heat exchanger.

Abstract: A passive high-pressure safety injection system includes a compressor which generates high-temperature and high-pressure steam, a cooling water supply tank which supplies cooling water using the compressed steam, a nuclear reactor which receives the cooling water so that the nuclear reactor is maintained in a cooled state, and an internal circulation prevention structure which is provided in the cooling water supply tank and prevents the cooling water from circulating in the cooling water supply tank.

Abstract: A residual heat removal system for a nuclear power plant. The residual heat removal system for a nuclear power plant may include an air duct provided on an outside of a reactor containment building, a heat exchanger disposed on an inside of the air duct, a first pipe to transfer, to the heat exchanger, steam generated in a steam generator disposed on an inside of the reactor containment building, and second pipe to transfer, to the steam generator, water condensation that is cooled and condensed in the heat exchanger, wherein the heat exchanger is air-cooled using outside air flowing inside of the air duct.

Abstract: A high pressure safety injection tank (HPSIT) system includes one safety injection tank (HIT) which replaces a core makeup tank (CMT) and a low pressure (approximately 4.3 Mpa or below) safety injection tank (SIT) and which can shift to and operate on a high pressure (approximately 17 Mpa) operation mode, to enable injection of emergency core coolant into a reactor system both under low pressure (approximately 4.3 Mpa or below) and high pressure (approximately 17 Mpa).

Abstract: Provided is a passive containment air cooling device with an isolated pressure boundary, including a heat exchanger positioned inside and outside a containment, penetrating through an outer wall of the containment to be connected to the containment through a pipe and thus form a closed loop, and including a coolant, an air induction duct circulating air outside the heat exchanger, and a cooled air exhaust unit formed in the air induction duct to increase cooling efficiency of the heat exchanger.

Abstract: A passive high-pressure safety injection system includes a compressor which generates high-temperature and high-pressure steam, a cooling water supply tank which supplies cooling water using the compressed steam, a nuclear reactor which receives the cooling water so that the nuclear reactor is maintained in a cooled state, and an internal circulation prevention structure which is provided in the cooling water supply tank and prevents the cooling water from circulating in the cooling water supply tank.

Abstract: Disclosed herein is a water-air combined passive feed water cooling apparatus including a water cooling heat exchanger connected to the inside of a containment building to cool down heat of a steam generator using a water cooling method, a cooling tank including the water cooling heat exchanger therein and storing cooling water condensing main steam generated by the steam generator, an evaporative steam pipe connected to the cooling tank, the evaporative steam pipe, into which steam of the cooling water generated by the water cooling heat exchanger in the cooling tank flows, an air cooling heat exchanger connected to the evaporative steam pipe and cooling down and liquefying the steam flowing into the evaporative steam pipe, and a condensed water collecting pipe for refilling the cooling tank with the steam liquefied by the air cooling heat exchanger.

Abstract: The present invention relates to a longitudinally divided emergency core cooling (ECC) duct in order to efficiently inject safety water to core of a pressurized light-water nuclear reactor. The ECC duct includes side supports for preventing the flow-induced vibration in the annular downcomer, and has structural stability while thermally expanding and contracting. A longitudinally divided ECC duct for emergency core cooling water injection of a nuclear reactor is provided on the periphery of a core barrel of a nuclear reactor, includes an emergency core cooling water inlet facing a direct vessel injection nozzle, and extends in a longitudinal direction of the core barrel. The longitudinally divided ECC duct is divided into a plurality of longitudinally-divided ducts in the longitudinal direction of the longitudinally divided ECC duct.

Abstract: A residual heat removal system for a nuclear power plant. The residual heat removal system for a nuclear power plant may include an air duct provided on an outside of a reactor containment building, a heat exchanger disposed on an inside of the air duct, a first pipe to transfer, to the heat exchanger, steam generated in a steam generator disposed on an inside of the reactor containment building, and second pipe to transfer, to the steam generator, water condensation that is cooled and condensed in the heat exchanger, wherein the heat exchanger is air-cooled using outside air flowing inside of the air duct.

Abstract: A high pressure safety injection tank (HPSIT) system includes one safety injection tank (HIT) which replaces a core makeup tank (CMT) and a low pressure (approximately 4.3 Mpa or below) safety injection tank (SIT) and which can shift to and operate on a high pressure (approximately 17 Mpa) operation mode, to enable injection of emergency core coolant into a reactor system both under low pressure (approximately 4.3 Mpa or below) and high pressure (approximately 17 Mpa).

Abstract: An emergency core cooling system directly injects emergency core cooling water, which is supplied from a high-pressure safety injection pump or a safety injection tank for a pressurized light water reactor, into a reactor vessel downcomer. A pipe connector is completely removed from between each direct vessel injection nozzle and each injection extension duct installed on an outer surface of the core barrel, which are opposite to each other. An emergency core cooling water intake port, through which the water is injected from each direct vessel injection nozzle, is formed on the surface of each injection extension duct facing an axis of each direct vessel injection nozzle. Thereby, a structure in which a jet of the emergency core cooling water flows into the injection extension ducts is adopted in a hydraulic connection fashion.

Abstract: A safety injection tank, used for quickly injecting emergency core cooling water (ECCW) to a reactor vessel in the case of a cold leg large break accident (CLLBA) in a pressurized water reactor (PWR), is disclosed. The safety injection tank has a gravity-driven fluidic device configured to efficiently change the ECCW injection mode from a high flow injection mode to a low flow injection mode. The gravity-driven fluidic device includes a spring placed in the upper end of the vertical pipe, and a vertically movable water tub placed on the spring so as to be movable in a vertical direction. When ECCW contained in the pressure vessel is discharged and the water level is reduced lower than the height of the tub, the tub is moved downwards such that the lower surface thereof comes into contact with the vertical pipe and closes the high flow inlet port.

Abstract: The present invention relates to a longitudinally divided emergency core cooling (ECC) duct in order to efficiently inject safety water to core of a pressurized light-water nuclear reactor. The ECC duct includes side supports for preventing the flow-induced vibration in the annular downcomer, and has structural stability while thermally expanding and contracting. A longitudinally divided ECC duct for emergency core cooling water injection of a nuclear reactor is provided on the periphery of a core barrel of a nuclear reactor, includes an emergency core cooling water inlet facing a direct vessel injection nozzle, and extends in a longitudinal direction of the core barrel. The longitudinally divided ECC duct is divided into a plurality of longitudinally-divided ducts in the longitudinal direction of the longitudinally divided ECC duct.