Abstract: Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

Abstract: A system for monitoring a condition of a nuclear reactor pressure vessel disposed in a radioactive environment includes an instrument structured to monitor a condition of the nuclear reactor pressure vessel; a powered wireless transmitting modem disposed in the radioactive environment, the wireless transmitting modem being electrically coupled to the instrument; a receiving modem disposed in the line of sight of the transmitting modem, the receiving modem being in wireless communication with the transmitting modem; and a signal processing unit electrically coupled to the receiving modem, the signal processing unit being structured to determine the condition of the nuclear reactor pressure vessel from the instrument. The transmitting modem is powered by a thermocouple disposed in or on the reactor pressure vessel.

Abstract: Filtering systems and methods remove debris from coolant in a nuclear reactor setting. One or more filters are installed outside coolant reservoirs specifically where coolant will flow toward the reservoir, such as during a transient or other coolant leak event. Useable filters permit coolant through-flow while catching, straining, diverting, or otherwise removing debris from the coolant without significant interference with the coolant flow. Filters can be installed at any location in a flow path for coolant flowing toward the reservoir, including pipes draining into a suppression pool, floor or personnel platform gratings, areas around main steam legs or steam generators, in a reactor drywell, etc. One or more filters are installed by securing the filter in a coolant flow path into a coolant source. Installation and maintenance can be performed during any maintenance period.

Abstract: A nuclear fuel assembly is provided for a boiling water reactor. The nuclear fuel assembly includes a base, a head, and a bundle of full length fuel rods and partial length fuel rods, said bundle extending upwardly and longitudinally from the base to the head. The nuclear fuel assembly includes at least one clamp for longitudinally retaining a lower plug of a partial length fuel rod with respect to the base. The clamp is an additional part fitted to the base, the clamp is at least partially received in a housing provided in the base, and the clamp is assembled to the base by mechanical engagement of complementary assemblies.

Abstract: A nuclear fission reactor fuel assembly and system configured for controlled removal of a volatile fission product and heat released by a burn wave in a traveling wave nuclear fission reactor and method for same. The fuel assembly comprises an enclosure adapted to enclose a porous nuclear fuel body having the volatile fission product therein. A fluid control subassembly is coupled to the enclosure and adapted to control removal of at least a portion of the volatile fission product from the porous nuclear fuel body. In addition, the fluid control subassembly is capable of circulating a heat removal fluid through the porous nuclear fuel body in order to remove heat generated by the nuclear fuel body.

Abstract: An assembly is provided that includes at least one first conduit and at least one second conduit connected together through a connecting device. The connecting device includes an exteriorly threaded tube; a connecting part attached to one end of the tube and including an orifice; a holding nut screwed onto the tube and axially maintaining the connecting part relative to a tube; and a retaining member attached on the holding nut and engaging with the first conduit so as to axially retain the first conduit fitted into the orifice, the retaining member cooperating with the first conduit so as to oppose the unscrewing of the holding nut.

Abstract: An automated system for on-line monitoring and coil diagnostics of rod position indicator (RPI) coils coil diagnostic, or RPI coil diagnostic system. The RPI coil diagnostic system performs coil diagnostics for a RPI system in a nuclear power plant. The RPI coil diagnostic system is in electrical communication with and monitors the outputs of the detector coils. The RPI coil diagnostic system measures characteristics of the detector coils that are indicative of the health of the detector coils and/or the connections between the detector coils and the RPI electronics.

Abstract: A method and system for the thermoelectric conversion of nuclear reactor generated heat including upon a nuclear reactor system shutdown event, thermoelectrically converting nuclear reactor generated heat to electrical energy and supplying the electrical energy to a mechanical pump of the nuclear reactor system.

Abstract: A system, method and apparatus for remotely installing a flange cover assembly on a fuel transfer tube fixed flange in a containment pit in a nuclear power plant is presented. In one example, the flange cover assembly includes J-bolt spring assemblies in which the feet of the J-bolt are rotated between a clamping and non-clamping orientation to engage with the rear face of the fixed flange. A tool frame is lowered into the containment pit to engage with the flange cover assembly to compress the J-bolt springs and extend the J-bolt foot toward and away from the flange cover. Dual acting cylinders move a spring compression frame on the frame tool to compress and relax the J-bolt spring assemblies.

Abstract: An object of the present invention is to efficiently improve uniformity of energy lines to be irradiated.

Abstract: A tritium removal device for a lithium loop contains a neutron source (1) for colliding protons on a lithium flow, thereby generating neutrons, a lithium tank (11) for the lithium passing through this neutron source (1) to flow thereto through a flow passage (9), thereby temporarily accumulating it therein, and a lithium pump (17) for circulating and supplying the lithium of this lithium tank (11) to the neutron source (1) through a supply-side flow passage (9?). The lithium tank (11) and the lithium pump (17), into which hydrogen gas containing tritium therein can be easily collected, are enclosed within a hermetically sealed container (7) including an inactive gas therein, so that even if the hydrogen gas including the tritium therein is leaked into the hermetically sealed container (7), it is removed by a hydrogen isotope removal filter.

Abstract: A nuclear fission reactor fuel assembly and system configured for controlled removal of a volatile fission product and heat released by a burn wave in a traveling wave nuclear fission reactor and method for same. The fuel assembly comprises an enclosure adapted to enclose a porous nuclear fuel body having the volatile fission product therein. A fluid control subassembly is coupled to the enclosure and adapted to control removal of at least a portion of the volatile fission product from the porous nuclear fuel body. In addition, the fluid control subassembly is capable of circulating a heat removal fluid through the porous nuclear fuel body in order to remove heat generated by the nuclear fuel body.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: A neutron detector detects a neutron flux distribution of the inside of a reactor. The neutron detector includes a thimble guide tube that is inserted inside of the reactor, for inserting the neutron detector. A drive apparatus is connected to the thimble guide tube for inserting or extracting the neutron detector into or out of the thimble guide tube. A vacuum unit controls the vacuum state in the thimble guide tube. A supply unit supplies carbon dioxide gas. A gas purge unit is connected to the supply unit and conducts gas purge in the thimble guide tube. A gate valve is provided between the thimble guide tube and the drive apparatus, and performs an open/close operation. A control apparatus controls the gate valve, the drive apparatus, the vacuum unit, the supply unit, and the gas purge unit.

Abstract: This invention relates to a method of preparing a nuclear fuel including the step of depositing a coating which includes fluorine, or at least one compound thereof, around a kernel (12) of fissile material. The invention extends to a coated nuclear fuel particle (10).

Abstract: The present invention takes the form of an apparatus or system that provides an alternate source of the pneumatic fluid to a system inside containment of a nuclear powerplant. An embodiment of the present invention may provide a nearly radiation-proof and nearly leak-proof, pneumatic fluid supply for some systems of the nuclear powerplant. These systems may include, but is not limited to, actuators, valves, and the like. An embodiment of the present invention may comprise a device that may propel an object with a sufficient force to puncture a seal of a pressure vessel. The released pneumatic fluid may be ported to an actuator, valve, or the like, for immediate operation of a system of the nuclear powerplant. Alternately, in an embodiment of the present invention, the pneumatic fluid may be used to resupply a depleted accumulator, or the like.

Abstract: A pressurized water reactor (PWR) includes a vertical cylindrical pressure vessel and a nuclear reactor core disposed in a lower vessel section. A hollow cylindrical central riser is disposed concentrically inside the pressure vessel. A downcomer annulus is defined between the central riser and the pressure vessel. A reactor coolant pump (RCP) includes (i) an impeller disposed above the nuclear reactor core and in fluid communication with the downcomer annulus to impel primary coolant downward through the downcomer annulus, (ii) a pump motor disposed outside of the pressure vessel, and (iii) a drive shaft operatively connecting the pump motor with the impeller. The PWR may include an internal steam generator in the downcomer annulus, with the impeller is disposed below the steam generator. The impeller may be disposed in the downcomer annulus. The RCP may further comprise a pump casing that with the impeller defines a centrifugal pump.

Abstract: Example embodiments are directed to methods of producing desired isotopes in commercial nuclear reactors using instrumentation tubes conventionally found in nuclear reactor vessels to expose irradiation targets to neutron flux found in the operating nuclear reactor. Example embodiments include assemblies for retention and producing radioisotopes in nuclear reactors and instrumentation tubes thereof. Example embodiments include one or more retention assemblies that contain one or more irradiation targets and are useable with example delivery systems that permit delivery of irradiation targets. Example embodiments may be sized, shaped, fabricated, and otherwise configured to successfully move through example delivery systems and conventional instrumentation tubes while containing irradiation targets and desired isotopes produced therefrom.

Abstract: A debris filter for a nuclear reactor installation is provided. The debris filter comprises a plurality of plates arranged side-by-side in a spaced relationship and delimiting between them flow passages extending through the debris filter from a lower inlet face to an upper outlet face of the debris filter, each passage having an intermediate section offset with respect to an inlet section and an outlet section. At least one of the plates is formed with debris catching features distributed along the plate and protruding into at least one passage delimited by the plate.

Abstract: A pressurized water nuclear reactor (PWR) includes a pressure vessel having a lower portion containing a nuclear reactor core comprising a fissile material and an upper portion defining an internal pressurizer volume. A condenser is secured to, and optionally supported by, the upper portion of the pressure vessel. A condenser inlet is in fluid communication with the internal pressurizer volume. A heat sink is in fluid communication with the condenser such that the condenser operates as a passive heat exchanger to condense steam from the internal pressurizer volume into condensate while rejecting heat to the heat sink. A condenser outlet connects with the pressure vessel to return condensate to the pressure vessel. A single metal forging having a first end welded to the pressure vessel and a second end welded to the condenser inlet may provide the fluid communication between the condenser inlet and the internal pressurizer volume.