A method that provides a more direct indication of peak fuel rod centerline temperature and peak fuel rod clad temperature than conventionally inferred from the power distribution by directly and continuously measuring the fuel temperatures of the fuel pellets in one or more of the hottest fuel elements in the core. The peak fuel rod clad temperature is then obtained from the maximum measured peak fuel rod centerline temperature in combination with the maximum coolant core exit temperature and the minimum coolant flow rate.

A digital protection system includes a process protection system having at least two channels and a reactor protection system having at least two trains. The process protection system includes, in one channel, first and second comparative logic controllers of different types that are mutually independent of each other and that respectively receive process variables as inputs and each outputting comparison logic results. The reactor protection system includes, in one train, first and second concurrent logic controllers of different types that are mutually independent from each other and that respectively receive the comparison logic results as inputs and each outputting concurrent logic results. The reactor protection system includes initiation circuits, each circuit including a plurality of relays connected in series and a plurality of relays connected in parallel. One series-connected relay is controlled by one of the two different concurrent logic results, and one parallel-connected relay is controlled by the other.

A digital protection system includes a process protection system having at least two channels and a reactor protection system having at least two trains. The process protection system includes, in one channel, first and second comparative logic controllers of different types that are mutually independent of each other and that respectively receive process variables as inputs and each outputting comparison logic results. The reactor protection system includes, in one train, first and second concurrent logic controllers of different types that are mutually independent from each other and that respectively receive the comparison logic results as inputs and each outputting concurrent logic results. The reactor protection system includes initiation circuits, each circuit including a plurality of relays connected in series and a plurality of relays connected in parallel. One series-connected relay is controlled by one of the two different concurrent logic results, and one parallel-connected relay is controlled by the other.

The present disclosure relates to a narrow slit channel visualization experimental device and method under a six-degree-of-freedom motion condition. The system comprises a six-degree-of-freedom motion simulation platform, a main circulation loop, a cooling water system, an electric heating system and a bubble monitoring system, wherein the main circulation loop is composed of an S-shaped preheater, a three-surface visualization experimental section, a double-pipe condenser, a pressurizing circulating pump, a voltage stabilizer and related equipment, wherein the cooling water system is composed of the double-pipe condenser, a plate heat exchanger, a cooling tower, a cooling fan, a cooling water tank and related equipment, wherein the electric heating system is composed of a direct-current power supply, a low-voltage power controller and a transformer, and wherein the bubble monitoring system is composed of two high-speed cameras, a PIV measuring system and an electric servo module.

The present disclosure relates to a narrow slit channel visualization experimental device and method under a six-degree-of-freedom motion condition. The system comprises a six-degree-of-freedom motion simulation platform, a main circulation loop, a cooling water system, an electric heating system and a bubble monitoring system, wherein the main circulation loop is composed of an S-shaped preheater, a three-surface visualization experimental section, a double-pipe condenser, a pressurizing circulating pump, a voltage stabilizer and related equipment, wherein the cooling water system is composed of the double-pipe condenser, a plate heat exchanger, a cooling tower, a cooling fan, a cooling water tank and related equipment, wherein the electric heating system is composed of a direct-current power supply, a low-voltage power controller and a transformer, and wherein the bubble monitoring system is composed of two high-speed cameras, a PIV measuring system and an electric servo module.

A system for measuring flow rate within a volume includes one or more transmission devices that transmit one or more signals through fluid contained within the volume. The volume may be bounded, at least in part, by an outer structure and by an object at least partially contained within the outer structure. A transmission device located at a first location of the outer structure transmits a first signal to a second location of the outer structure. A second signal is transmitted through the fluid from the second location to a third location of the outer structure. The flow rate of the fluid within the volume may be determined based, at least in part, on the time of flight of both the first signal and the second signal.

A system for measuring flow rate within a volume includes one or more transmission devices that transmit one or more signals through fluid contained within the volume. The volume may be bounded, at least in part, by an outer structure and by an object at least partially contained within the outer structure. A transmission device located at a first location of the outer structure transmits a first signal to a second location of the outer structure. A second signal is transmitted through the fluid from the second location to a third location of the outer structure. The flow rate of the fluid within the volume may be determined based, at least in part, on the time of flight of both the first signal and the second signal.

A jet pump measuring pipe repair method that repairs a ruptured part of a measuring pipe horizontally installed to a lower portion of a jet pump provided in reactor water inside a reactor pressure vessel. The repair method includes: fixing a support member to the jet pump near the measuring pipe left remained; mounting, after the support member fixing, a measuring pipe connector provided with a pipe-repairing pipe having both ends over which connecting pipes are fitted, respectively, to the support member; connecting, after the connector mounting, the remaining measuring pipe and connecting pipe using the measuring pipe connector.

A jet pump measuring pipe repair method that repairs a ruptured part of a measuring pipe horizontally installed to a lower portion of a jet pump provided in reactor water inside a reactor pressure vessel. The repair method includes: fixing a support member to the jet pump near the measuring pipe left remained; mounting, after the support member fixing, a measuring pipe connector provided with a pipe-repairing pipe having both ends over which connecting pipes are fitted, respectively, to the support member; connecting, after the connector mounting, the remaining measuring pipe and connecting pipe using the measuring pipe connector.

A system for controlling the power level of a natural circulation boiling water nuclear reactor (NCBWR) may include a heating subsystem for heating feedwater flowing into an annulus of the NCBWR to increase the temperature of recirculation water flowing through the core above a predetermined recirculation water operating temperature. Additionally the system may include a temperature sensor operable to sense the temperature of the feedwater flowing into the annulus. The temperature sensor is communicatively connected to a temperature controller operable to command the heating subsystem to increase the temperature of the feedwater flowing into the annulus to a requested temperature above a predetermined operating temperature of the feedwater flowing into the annulus. By increasing the temperature of the feedwater flowing into the annulus, the temperature of the recirculation water is increased above the predetermined recirculation water operating temperature causing a reduction in the power level generated by the NCBWR core.