Korea Atomic Energy Research Institute

Korea Hydro Nuclear Power Co., Ltd.

Korea Hydro and Power Co., Ltd.

Won-Pil Baek

Tae-Soon Kwon

Chul-Hwa Song

Dong-Jin Euh

In-Chul Chu

Byong-Jo Yun

Kyoung-Ho Kang

Jong-kyun Park

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).

Passive high pressure safety injection tank system (HPSIT) for responding to station blackout (SBO) and loss-of-coolant accidents (LOCA)

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.

Emergency core cooling system having core barrel injection extension ducts

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.

Safety injection tank with gravity driven fluidic device

An average bidirectional flow tube, including a body having two side plates and upper and lower plates, a partition plate installed to be perpendicular to the side plates of the body so that front and rear ends of the tube are separated from each other, and two pairs of pressure impulse lines installed at front and rear positions of the partition plate. The upper and lower plates of the body each have a curvature to be in contact with an inner surface of a pipe in which the average bidirectional flow tube is installed, and each of the pressure impulse lines is installed to communicate with an interior of the pipe. Although a two-phase flow occurs in the pipe or the flow of the fluid flowing in the pipe is changed, an average flow rate of a fluid can be measured. Particularly, it is easy to measure an average flow rate of the fluid when the fluid flows at a low speed. Further, even when sudden pressure reduction occurs in the pipe, an additional cooling device is not required. When a two-phase flow occurs in the pipe, the fluid suffers a phase change due to the sudden pressure reduction of the pipe, or a stratified flow occurs due to the two-phase flow in a horizontal pipe, it is unnecessary to displace the average bidirectional flow tube.

Average bidirectional flow tube

A direct vessel injection-type pressurized light water reactor (DVI-PLWR), in which an emergency core cooling water (ECC) is directly injected into a downcomer of a reactor vessel, is disclosed. In order to reduce the ratio of ECC bypass from the downcomer to a broken area of a cold leg in the case of a cold leg guillotine break (CLGB), such as a double-ended guillo4tine break (DEGB), a plurality of corrugations, having a V-shaped cross-section, are vertically arranged around each of the inner surface of a pressure vessel and the outer surface of a core barrel at regular intervals, with a vertical groove formed between two neighboring corrugations. The grooves phase-separate the ECC from a high-speed lateral flow of fluid running in the downcomer, and the separated ECC stagnates in the form of vortexes in the grooves, prior to flowing down to the lower section of the downcomer due to gravity. The DVI-PLWR thus reduces the ratio of ECC bypass, and a large amount of ECC reaches the reactor core in the case of a large break loss-of-cooling water accident (LBLOCA) caused by DEGB. It is thus possible to limit an increase in the maximum cladding temperature of fuel rods, and to prevent the reactor core from being reheated at the late reflood phase after the DEGB-caused LBLOCA, so that the desired thermal hydraulic safety of the DVI-PLWR is secured.

Growing community of inventors

Daejeon, South Korea

Won-Pil Baek