The present disclosure provides a stopped cooling system including: a steam line connecting portion connected to a steam line so as to receive cooling water through the steam line connected to an outlet of a steam generator; a stopped cooling heat exchanger for receiving cooling water that enters the stopped cooling system through the steam line connecting portion, and discharging same through a passage of the heat exchanger; a stopped cooling pump activated to perform stopped cooling of the nuclear reactor upon normal stoppage of the nuclear reactor after primary cooling of the nuclear reactor cooling system or when an accident occurs, and for forming a circulating flow of cooling water that circulates between the steam generator and the stopped cooling heat exchanger; and a water supplying pipe connecting portion connected to the heat exchanger passage and a water supplying pipe, which is connected to the inlet of the steam generator, so as to supply the cooling water cooled in the stopped cooling heat exchanger to the steam generator through the water supplying pipe.

Controlled-debris elements inhibit the formation of a fibrous/particulate debris bed that unduly increases the pressure head loss through the perforated plates of strainers in a nuclear power plant emergency core cooling system. In a loss of cooling accident, pumps draw cooling water through the plates, which retain on their surfaces fibrous material in the circulating water to prevent it from reaching the pumps while permitting entrained particulate matter to pass through the perforations. The controlled-debris elements have a specific gravity substantially the same as the circulating water so they are entrained in the cooling water that is drawn toward the strainers and intimately intermix with the fibrous and particulate matter in the cooling water. The elements are configured to provide open structures in the bed formed on the plate surfaces to distribute fibers in the flow away from the surface and maintain cavities between the elements for the particulates.

The present invention provides a porous cooling block for cooling corium, comprising: a base part that includes a plurality of pores; a plurality of porous cooling blocks that include a channel part that communicates with some of the plurality of pores of the base part; a sacrificial part that covers the exposed upper surfaces of the porous cooling blocks; and a cooling-water supply unit that supplies cooling water to the porous cooling blocks. Corium is cooled by using steam or cooling water discharged from the porous cooling blocks. Therefore, the corium can be cooled and solidified in the shape of a porous form. Further, the cooling water is uniformly supplied to one surface formed by the cooling block on the whole, thereby easily cooling the corium.

In conjunction with a pressurized water reactor (PWR) and a pressurizer configured to control pressure in the reactor pressure vessel, a decay heat removal system comprises a pressurized passive condenser, a turbine-driven pump connected to suction water from at least one water source into the reactor pressure vessel; and steam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. The pump and turbine may be mounted on a common shaft via which the turbine drives the pump. The at least one water source may include a refueling water storage tank (RWST) and/or the pressurized passive condenser. A pressurizer power operated relief valve may control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer.

Disclosed is a nuclear power plant which drives a Stirling engine by means of heat generated in nuclear power plant safety systems during an accident, uses the resulting power directly or generates electric power so as to supply the power to the safety systems, and thus can improve economic efficiency as well as the reliability of safety systems, such as a passive safety system, by operating the safety systems without an emergency diesel generator or external electric power.

A face plate (10, 11), made of silicon nitride, of a seal package (1) for a sealing system (4) of a shaft (7) of a reactor coolant pump in a nuclear reactor, is intended to ensure sealing between the primary circuit and the atmosphere. The face plate (10, 11) has an active surface covered by a protective layer (13) made from a nonporous material that is chemically inert to pressurized water superheated to a temperature greater than or equal to 200 C.

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 in-vessel cooling and power generation system according to the present disclosure may be continuously operated not only during a normal operation but also during an accident to perform in-vessel cooling, and produce emergency power, thereby improving the system reliability. In addition, the in-vessel cooling and power generation system according to the present disclosure may facilitate the application of a safety class or seismic design with a small scale facility, thereby improving the reliability due to the application of the safety class or seismic design.

An assembly for containing and detecting leaks from a coolant line includes a basin with side and end walls, and at least one U-shaped cavity in an end wall for receiving a coolant line of a liquid cooling system. A bottom of the basin includes at least one sloped interior surface arranged to divert water in the basin to a local low point, where a sensor is positioned and operable to detect liquid in the collection basin. A leak detection system can employ a leak detection assembly to detect and/or locate a leak.

A reactor cooling and power generation system according to the present invention includes a reactor vessel, a heat exchange section to receive heat generated from a core inside the reactor vessel through a fluid, and a power production section having a thermoelectric element configured to produce electric energy using energy of the fluid whose temperature has increased while receiving the heat of the reactor, wherein the system is configured to allow the fluid that has received the heat from the core to circulate through the power production section, and to operate even during an accident as well as during a normal operation of a nuclear power plant to produce electric power.

Also, the reactor cooling and power generation system according to the present invention may continuously operate during an accident as well as a normal operation so as to cool the reactor and produce emergency power, thereby improving system reliability. In addition, the reactor cooling and power generation system according to the present invention may facilitate application of safety class or seismic design with a small scale facility, thereby improving the reliability owing to the application of the safety class or seismic design.

Integrated passive reactor including a reactor primary circuit, a containment cooling system, a residual heat removal system, and a reactor core cooling system. Loop resistance is reduced by means of a reactor-type process design, a flow guide device is provided at a rising section of fluid to reduce the loop resistance, the rising section is shrunken to increase the arrangement space of a heat exchanger so as to further optimize system resistance, and the designs of an infinite-time passive reactor core residual heat removal system and an infinite-time passive containment cooling system are achieved. By means of the rational configuration of a pressure relief system, high-pressure safety injection is removed, and the passive reactor core cooling system is simplified. By means of the design of an auxiliary circulation device for a loss of coolant accident, the safety of a reactor core in the loss of coolant accident is further enhanced.