Abstract: A molten metal level measuring device in a continuous molten metal level measuring device uses temperature compensation. The device includes a cylindrical bobbin, a liquid level measuring unit helically wound around an outer surface of the bobbin, a circular inner cylinder in which the bobbin and the liquid level measuring part are located and which seals the bobbin and the liquid level measuring part from the outside and has the same axial direction as the bobbin, and a cylindrical protective tube in which the inner cylinder is located and which has the same axial direction as the bobbin and has one open end. Thermocouples extend axially in the space between the inner cylinder and the protective tube, and a control unit controls the liquid level measuring part to measure a liquid level of the molten metal based on the temperatures measured by the thermocouples.

Abstract: A molten metal level measuring device in a continuous molten metal level measuring device uses temperature compensation. The device includes a cylindrical bobbin, a liquid level measuring unit helically wound around an outer surface of the bobbin, a circular inner cylinder in which the bobbin and the liquid level measuring part are located and which seals the bobbin and the liquid level measuring part from the outside and has the same axial direction as the bobbin, and a cylindrical protective tube in which the inner cylinder is located and which has the same axial direction as the bobbin and has one open end. Thermocouples extend axially in the space between the inner cylinder and the protective tube, and a control unit controls the liquid level measuring part to measure a liquid level of the molten metal based on the temperatures measured by the thermocouples.

Abstract: An apparatus and method for monitoring a flow of liquid in a pipe are provided. The apparatus may include a temperature sensor attached to a pipe of a heat exchanger system to measure a temperature of the pipe, and a controller to determine whether a liquid is present in the pipe, based on a change in the measured temperature.

Abstract: Disclosed herein is a fully passive decay heat removal system utilizing a partially immersed heat exchanger, the system comprising: a hot pool; an intermediate heat exchanger which heat-exchanges with the sodium of the hot pool; a cold pool; a support barrel extending vertically through the boundary between the hot pool and the cold pool; a sodium-sodium decay heat exchanger received in the support barrel; a sodium-air heat exchanger provided at a position higher than the sodium-sodium decay heat exchanger; an intermediate sodium loop connecting the sodium-sodium decay heat exchanger with the sodium-air heat exchanger; and a primary pump, wherein a portion of the effective heat transfer tube of the sodium-sodium decay heat exchanger is immersed in the cold pool, particularly in a normal operating state, and the surface of the lower end of a shroud for the sodium-sodium decay heat exchanger, the lower end being immersed in the sodium of the cold pool, has perforated holes.

Abstract: An apparatus and method for monitoring a flow of liquid in a pipe are provided. The apparatus may include a temperature sensor attached to a pipe of a heat exchanger system to measure a temperature of the pipe, and a controller to determine whether a liquid is present in the pipe, based on a change in the measured temperature.

Abstract: Disclosed herein is a decay heat removal system, including: a decay heat exchanger that absorbs decay heat generated by a nuclear reactor; a heat pipe heat exchanger that receives the decay heat from the decay heat exchanger through a sodium loop for heat removal and then discharges the decay heat to the outside; and a sodium-air heat exchanger that is connected to the heat pipe heat exchanger through the sodium loop and discharges the decay heat transferred thereto through the sodium loop to the outside. According to the decay heat removal system, a heat removal capability can be realized by the heat pipe heat exchanger at such a high temperature at which the safety of a nuclear reactor is under threat, and a cooling effect can be obtained through the sodium-air heat exchanger at a temperature lower than that temperature.

Abstract: Disclosed herein is a fully passive decay heat removal system utilizing a partially immersed heat exchanger, the system comprising: a hot pool; an intermediate heat exchanger which heat-exchanges with the sodium of the hot pool; a cold pool; a support barrel extending vertically through the boundary between the hot pool and the cold pool; a sodium-sodium decay heat exchanger received in the support barrel; a sodium-air heat exchanger provided at a position higher than the sodium-sodium decay heat exchanger; an intermediate sodium loop connecting the sodium-sodium decay heat exchanger with the sodium-air heat exchanger; and a primary pump, wherein a portion of the effective heat transfer tube of the sodium-sodium decay heat exchanger is immersed in the cold pool, particularly in a normal operating state, and the surface of the lower end of a shroud for the sodium-sodium decay heat exchanger, the lower end being immersed in the sodium of the cold pool, has perforated holes.

Abstract: Disclosed herein is a decay heat removal system, including: a decay heat exchanger that absorbs decay heat generated by a nuclear reactor; a heat pipe heat exchanger that receives the decay heat from the decay heat exchanger through a sodium loop for heat removal and then discharges the decay heat to the outside; and a sodium-air heat exchanger that is connected to the heat pipe heat exchanger through the sodium loop and discharges the decay heat transferred thereto through the sodium loop to the outside. According to the decay heat removal system, a heat removal capability can be realized by the heat pipe heat exchanger at such a high temperature at which the safety of a nuclear reactor is under threat, and a cooling effect can be obtained through the sodium-air heat exchanger at a temperature lower than that temperature.

Abstract: A direct pool cooling type passive safety grade decay heat removal method and system for removing core decay heat in a pool type liquid metal reactor when a normal heat removal system breaks down. In the liquid metal reactor comprising a reactor vessel, the interior of which is partitioned into a hot pool above a core and a cold pool around the core so that liquid level difference between the hot pool and the cold pool is maintained by a primary pumping head under normal steady-state conditions, is disposed at least one circular vertical tube in such a manner that the sodium in the circular vertical tube is maintained with the same liquid level as the liquid level of the sodium in the cold pool.

Abstract: Dis0closed herein is a direct pool cooling type passive safety grade decay heat removal method and system for removing core decay heat in a pool type liquid metal reactor when a normal heat removal system breaks down. In the liquid metal reactor comprising a reactor vessel, the interior of which is partitioned into a hot pool above a core and a cold pool around the core so that liquid level difference between the hot pool and the cold pool is maintained by a primary pumping head under normal steady-state conditions, is disposed at least one circular vertical tube in such a manner that the sodium in the circular vertical tube is maintained with the same liquid level as the liquid level of the sodium in the cold pool.