A method of operating a nuclear reactor includes operating a valve actuator to open and close a valve in fluid communication with a nuclear reactor fluid control system. The valve actuator includes a motor having windings of magnet wire. The magnet wire includes a layer of insulating material disposed over a conductor. The layer of insulating material comprises polyetheretherketone (PEEK) and has a thickness between about 0.025 mm and about 0.381 mm. A method of replacing a valve actuator motor with such a motor having windings formed of PEEK-insulated magnet wire is also disclosed. A method of coupling a valve actuator with such a motor having windings formed of PEEK-insulated magnet wire to a valve is also disclosed.

A method of operating a nuclear reactor includes operating a valve actuator to open and close a valve in fluid communication with a nuclear reactor fluid control system. The valve actuator includes a motor having windings of magnet wire. The magnet wire includes a layer of insulating material disposed over a conductor. The layer of insulating material comprises polyetheretherketone (PEEK) and has a thickness between about 0.025 mm and about 0.381 mm. A method of replacing a valve actuator motor with such a motor having windings formed of PEEK-insulated magnet wire is also disclosed. A method of coupling a valve actuator with such a motor having windings formed of PEEK-insulated magnet wire to a valve is also disclosed.

Damper systems selectively reduce coolant fluid flow in nuclear reactor passive cooling systems, including related RVACS. Systems include a damper that blocks the flow in a coolant conduit and is moveable to open, closed, and intermediate positions. The damper blocks the coolant flow when closed to prevent heat loss, vibration, and development of large temperature gradients, and the damper passively opens, to allow full coolant flow, at failure and in transient scenarios. The damper may be moveable by an attachment extending into the coolant channel that holds the damper in a closed position. When a transient occurs, the resulting loss of power and/or overheat causes the attachment to stop holding the damper, which may be driven by gravity, pressure, a spring, or other passive structure into the open position for full coolant flow. A power source and temperature-dependent switch may detect and stop holding the damper closed in such scenarios.

Damper systems selectively reduce coolant fluid flow in nuclear reactor passive cooling systems, including related RVACS. Systems include a damper that blocks the flow in a coolant conduit and is moveable to open, closed, and intermediate positions. The damper blocks the coolant flow when closed to prevent heat loss, vibration, and development of large temperature gradients, and the damper passively opens, to allow full coolant flow, at failure and in transient scenarios. The damper may be moveable by an attachment extending into the coolant channel that holds the damper in a closed position. When a transient occurs, the resulting loss of power and/or overheat causes the attachment to stop holding the damper, which may be driven by gravity, pressure, a spring, or other passive structure into the open position for full coolant flow. A power source and temperature-dependent switch may detect and stop holding the damper closed in such scenarios.

The invention relates to a multi-component cladding for a nuclear fuel rod that includes a combination of ceramic and metal components. More particularly, the invention is directed to a cladding that includes a ceramic composite having a zirconium composition deposited thereon to form a zirconium coated ceramic composite. The ceramic composite includes a ceramic matrix and a plurality of ceramic fibers. The cladding is effective to protect the contents of the cladding structure from exposure to high temperature environments during various load conditions of a nuclear reactor.

Portable nuclear fuel cartridge comprising a unitary support structure and plurality of nuclear fuel assemblies that collectively form a nuclear fuel core. Control rod drive system for a nuclear reactor. A nuclear steam supply system having a shutdown system for removing residual decay heat generated by a nuclear fuel core. A nuclear reactor including a cylindrical body having an internal cavity, nuclear fuel core, and a shroud disposed in the cavity. A nuclear reactor cooling system with passive cooling capabilities operable during a loss-of-coolant accident (LOCA) without available electric power.

The invention relates to a multi-component cladding for a nuclear fuel rod that includes a combination of ceramic and metal components. More particularly, the invention is directed to a cladding that includes a ceramic composite having a zirconium composition deposited thereon to form a zirconium coated ceramic composite. The ceramic composite includes a ceramic matrix and a plurality of ceramic fibers. The cladding is effective to protect the contents of the cladding structure from exposure to high temperature environments during various load conditions of a nuclear reactor.

The invention relates to a multi-component cladding for a nuclear fuel rod that includes a combination of ceramic and metal components. More particularly, the invention is directed to a cladding that includes a ceramic composite having a zirconium composition deposited thereon to form a zirconium coated ceramic composite. The ceramic composite includes a ceramic matrix and a plurality of ceramic fibers. The cladding is effective to protect the contents of the cladding structure from exposure to high temperature environments during various load conditions of a nuclear reactor.

A passive cooling system for cooling the in-containment refueling water storage tank and the spent fuel pool of nuclear power plants that can extend the number of days the plants can safely be maintained without operator intervention. The cooling system employs a thermosiphon in a closed loop cycle that circulates a refrigerant around the cooling loop between heat exchangers within the spent fuel and in-containment refueling water and the ambient atmosphere outside the containment, by natural circulation.

A high reliable water injection device is provided that injects water into a reactor containment vessel and can reliably shut off cooling water at normal times and quickly and reliably inject water into the reactor containment vessel without the need for external power, in a case of emergency. The water injection device injects water into a reactor containment vessel includes a flow path through which cooling water is supplied; a disk that closes the flow path; a swing arm that is connected to the disk and performs closing and opening of the flow path by the disk; and a weight that is connected to the swing arm via a swing lever, in which the weight is supported by a support member made of a low melting point alloy.