Abstract: A pump leakage mitigation device includes one or more clamp arms on an outer surface of a pump that can be driven by a biasing element to seat against a shaft of the pump to seal or reduce fluid flow through a breakdown of the pump. The biasing element engages only at threshold temperatures, such as those associated with breakdown orifice failure when additional sealing may be necessary. Clamp arms of any number and shape can be used to achieve the desired seal and based on the pump geometry. A sealant surface and/or keeping mechanism are useable with the leakage mitigation device to enhance fluid flow blockage throughout a pump failure transient scenario. Pump leakage mitigation devices are installed on an outside of a variety of different pump types and can thus be installed, actuated, manipulated, disengaged, and/or removed without having to destroy or disassemble the pump.

Abstract: A pump leakage mitigation device includes one or more clamp arms on an outer surface of a pump that can be driven by a biasing element to seat against a shaft of the pump to seal or reduce fluid flow through a breakdown of the pump. The biasing element engages only at threshold temperatures, such as those associated with breakdown orifice failure when additional sealing may be necessary. Clamp arms of any number and shape can be used to achieve the desired seal and based on the pump geometry. A sealant surface and/or keeping mechanism are useable with the leakage mitigation device to enhance fluid flow blockage throughout a pump failure transient scenario. Pump leakage mitigation devices are installed on an outside of a variety of different pump types and can thus be installed, actuated, manipulated, disengaged, and/or removed without having to destroy or disassemble the pump.

Abstract: A method and system for external alternate suppression pool cooling for a Boiling Water Nuclear Reactor (BWR) that does not breach the Mark I primary containment. The external cooling system may include a heat sink fluidly coupled to cooling coils surrounding the suppression pool. Cool water may be pumped through the cooling coils without the need for normal plant electrical power, which is ideal during a plant emergency. The cooling system may also be operated and controlled from a remote location to protect the safety of plant personnel.

Abstract: A method of transferring heat from a nuclear plant may include: connecting a heat transfer system to the nuclear plant; and using the heat transfer system to transfer heat from the nuclear plant. The heat transfer system may include: a piping system that includes first and second connectors; a heat exchanger; a pump; and a power source. The heat transfer system may not be connected to the nuclear plant during normal plant power operations. The power source may be independent of a normal electrical power distribution system for the nuclear plant. The power source may be configured to power the pump. The piping system may be configured to connect the heat exchanger and pump. The first and second connectors may be configured to connect the heat transfer system to a fluid system of the nuclear plant.

Abstract: A temperature sensor array includes several temperature sensors at different positions for installation within an instrumentation tube of a nuclear reactor. The temperature sensors measure temperature at multiple axial positions of the nuclear reactor, and plant operators are able to access and interpret this measurement data. Temperatures associated with vessel coolant boiling or loss and/or fuel damage can be detected by the temperature sensors to permit more direct determinations of core fluid levels. Multiple temperature sensor arrays permit vessel fluid levels and conditions to be measured at multiple core locations.

Abstract: A method and apparatus for measuring a liquid level of a Spent Fuel Pool of a Light Water Reactor without using electrical power. The method and apparatus may use a pressurized gas source connected to tubing or piping that may discharge near the bottom of the Spent Fuel Pool. The system may include a flow meter and throttle valve that may be used to determine a required gas pressure to provide a specified flow rate of gas for known Spent Fuel Pool water levels. By obtaining calibration data points of pressure and flow for multiple Spent Fuel Pool water levels, a calibration curve may be obtained that allows for the measurement of Spent Fuel Pool liquid level using the system, without the need for electrical power.

Abstract: A method and apparatus for an alternative cooling system used to cool the suppression pool of a Boiling Water Reactor (BWR) nuclear reactor. The cooling system includes a cooling coil in an isolation condenser located at an elevation that is above the suppression pool. The isolation condenser is connected to the suppression pool via inlet and outlet pipes. The system may provide a natural convection flow of fluids between the suppression pool and the cooling coils to passively cool fluid from the suppression pool without requiring external electrical power.

Abstract: A method and system for an alternate energy removal path for a reactor pressure vessel (RPV) of a light water reactor. A pair of manually operated containment isolation valves, one located inside and one located outside of primary containment, are used to open and close a steam extraction line that is fluidly coupled between the RPV and a heat sink. The heat sink is located outside of primary containment. A source of external electrical power is not required to operate the system or perform the method.

Abstract: A method and system for measuring a temperature and liquid level of water within a Spent Fuel Pool (SFP) of a Light Water Reactor, without using external electrical power. The method and system may use a string of thermocouples attached to a cable and mounted in the spent fuel pool. The thermocouples supply their own power when heated by water that is exposed to the thermocouples within the spent fuel pool. The thermocouples may measure the temperature in the SFP. By measuring the temperature, the liquid water level of the SFP may be inferred by comparing a difference in temperature measurements of the thermocouples, as thermocouples exposed to ambient air will experience a noticeably different temperature from the thermocouples covered by water. The cable (with the thermocouples on one end) may terminate in a location that is remote from the SFP.

Abstract: A method and system for external alternate suppression pool cooling for a Boiling Water Nuclear Reactor (BWR) that does not breach the Mark I primary containment. The external cooling system may include a heat sink fluidly coupled to cooling coils surrounding the suppression pool. Cool water may be pumped through the cooling coils without the need for normal plant electrical power, which is ideal during a plant emergency. The cooling system may also be operated and controlled from a remote location to protect the safety of plant personnel.

Abstract: A heat transfer system for a nuclear plant may include a piping system that includes first and second connectors, heat exchanger, pump, and power source. The heat transfer system may not be connected to the plant during normal power operations. The power source may be independent of a normal electrical power distribution system for the plant and may be configured to power the pump. The piping system may be configured to connect the heat exchanger and pump. The connectors may be configured to connect the heat transfer system to a fluid system of the plant. When the connectors connect the heat transfer system to the fluid system, the heat transfer system may be configured to receive fluid from the fluid system of the plant via the first connector, to pump the fluid through the heat exchanger, and to return the fluid to the fluid system via the second connector.

Abstract: A temperature sensor array includes several temperature sensors at different positions for installation within an instrumentation tube of a nuclear reactor. The temperature sensors measure temperature at multiple axial positions of the nuclear reactor, and plant operators are able to access and interpret this measurement data. Temperatures associated with vessel coolant boiling or loss and/or fuel damage can be detected by the temperature sensors to permit more direct determinations of core fluid levels. Multiple temperature sensor arrays permit vessel fluid levels and conditions to be measured at multiple core locations.

Abstract: A pump leakage mitigation device includes one or more clamp arms on an outer surface of a pump that can be driven by a biasing element to seat against a shaft of the pump to seal or reduce fluid flow through a breakdown of the pump. The biasing element engages only at threshold temperatures, such as those associated with breakdown orifice failure when additional sealing may be necessary. Clamp arms of any number and shape can be used to achieve the desired seal and based on the pump geometry. A sealant surface and/or keeping mechanism are useable with the leakage mitigation device to enhance fluid flow blockage throughout a pump failure transient scenario. Pump leakage mitigation devices are installed on an outside of a variety of different pump types and can thus be installed, actuated, manipulated, disengaged, and/or removed without having to destroy or disassemble the pump.