A system is provided for use with a nuclear reactor which is mounted on a barge and which floats in a water tank. The system includes at least one water pipe which extends from a source of water to the interior of the tank. The system also includes a pipe which permits the drainage of water from the water tank. Valves are imposed in the piping so that the water in the tank will have a desired level and temperature. The system also enables fresh water to be supplied to the containment interior of the reactor. Further, the system includes piping and valves to supply water to the condenser and to drain water from the condenser. The system also includes flexible and slack tubular sections positioned in the piping between the barge and the water tank which allows the barge to move while maintaining the integrity of the tubing.

The present invention provides an alternative circulation cooling method for an emergency core cooling system that, even if the emergency core cooling system does not operate normally, can prevent the implementation of containment vessel venting by suppressing a rise in pressure and temperature in the containment vessel, and can suppress the implementation of dry-well venting even if containment vessel venting needs to be performed, as well as a nuclear power plant that is capable of the same. An alternative circulation cooling method for an emergency reactor core cooling system is performed at a nuclear power plant that includes an RHR system and a MUWC system. The method includes: connecting the downstream side of an RHR heat exchanger to the upstream side of a MUWC pump, and cooling water from a suppression chamber using the RHR heat exchanger and performing nuclear reactor injecting or containment vessel spraying using the MUWC pump.

A single-loop nuclear power plant with a pressurized coolant, comprising a power generating unit and a throttling device having an impeller, which are interconnected by an outlet pipe and a feed pipe, and a steam turbine connected to the throttling device and to a condenser connected to the throttling device, which device is a throttling steam generator vertically divided into a vapour zone, a high pressure zone, and a low pressure zone by horizontal sealed partitions. The high pressure zone is connected to the the feed pipe and is connected to the low pressure zone by throttling nozzles provided in the partition between said zones, and the low pressure zone is connected to the vapour zone by a vertical pipe which passes through the the horizontal sealed partitions and the high pressure zone. The single-loop nuclear power plant is provided with an electric motor to rotate the impeller.

The present invention provides an alternative circulation cooling method for an emergency core cooling system that, even if the emergency core cooling system does not operate normally, can prevent the implementation of containment vessel venting by suppressing a rise in pressure and temperature in the containment vessel, and can suppress the implementation of dry-well venting even if containment vessel venting needs to be performed, as well as a nuclear power plant that is capable of the same. An alternative circulation cooling method for an emergency reactor core cooling system is performed at a nuclear power plant that includes an RHR system and a MUWC system. The method includes: connecting the downstream side of an RHR heat exchanger to the upstream side of a MUWC pump, and cooling water from a suppression chamber using the RHR heat exchanger and performing nuclear reactor injecting or containment vessel spraying using the MUWC pump.

According to an embodiment, an emergency core cooling system has: three active safety divisions each including only one motor-driven active safety system; one passive safety division including a passive safety system; an emergency power source disposed in each of the active safety divisions to supply electric power to the motor-driven active safety system; and an advanced passive containment cooling system disposed in the passive safety division. Only two active safety divisions each includes a low pressure flooder system that is commonly used with a residual heat removal system as the only one motor-driven active safety system. The other active safety division includes an air-cooled injection system as the only one motor-driven active safety system.

Nuclear reactor systems and associated devices and methods are described herein. A representative nuclear reactor system includes a heat pipe network having an evaporator region, an adiabatic region, and a condenser region. The heat pipe network can define a plurality of flow paths having an increasing cross-sectional flow area in a direction from the evaporator region toward the condenser region. The system can further include nuclear fuel thermally coupled to at least a portion of the evaporator region. The heat pipe network is positioned to transfer heat received from the fuel at the evaporator region, to the condenser region. The system can further include one or more heat exchangers thermally coupled to the evaporator region for transporting the heat out of the system for use in one or more processes, such as generating electricity.

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.

An emergency cooling water system for a nuclear reactor which is mounted on a barge which floats in a water tank. The nuclear reactor includes an upstanding containment member having an interior compartment. At least one, and preferably two or more, cold water tubes are provided which have inner and outer ends with the outer ends of the cold water tubes being in communication with a source of cold water. The cold water tubes extend through the tank and the barge and have their inner ends in communication with the interior compartment of the nuclear reactor. In an emergency situation, cold water from the source of cold water is fed into the interior compartment of the containment member of the nuclear reactor.

A system is provided for use with a nuclear reactor which is mounted on a barge and which floats in a water tank. The system includes at least one water pipe which extends from a source of water to the interior of the tank. The system also includes a pipe which permits the drainage of water from the water tank. Valves are imposed in the piping so that the water in the tank will have a desired level and temperature. The system also enables fresh water to be supplied to the containment interior of the reactor. Further, the system includes piping and valves to supply water to the condenser and to drain water from the condenser. The system also includes flexible and slack tubular sections positioned in the piping between the barge and the water tank which allows the barge to move while maintaining the integrity of the tubing.

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.