Fuel, heat exchangers, and instrumentation for nuclear reactors are disclosed. A nuclear power system includes a plurality of nuclear fuel elements, each of the nuclear fuel elements including an annulus; and a plurality of heat pipes, each of the plurality of heat pipes configured to pass through the annulus of a respective one of the nuclear fuel elements in conductive thermal contact with the respective nuclear fuel element. A nuclear instrumentation module includes an assembly of optical fibers, each optical fiber comprising one or more sensors and configured for removable installation at one of the plurality of heat pipes. A heat exchanger includes a heat pipe including an evaporating region and a condensing region; and a tube bundle configured to wrap around the condensing region of the heat pipe and including one or more adjacent, parallel tubes, each tube forming a helix that is coaxial to the heat pipe.

Fuel, heat exchangers, and instrumentation for nuclear reactors are disclosed. A nuclear power system includes a plurality of nuclear fuel elements, each of the nuclear fuel elements including an annulus; and a plurality of heat pipes, each of the plurality of heat pipes configured to pass through the annulus of a respective one of the nuclear fuel elements in conductive thermal contact with the respective nuclear fuel element. A nuclear instrumentation module includes an assembly of optical fibers, each optical fiber comprising one or more sensors and configured for removable installation at one of the plurality of heat pipes. A heat exchanger includes a heat pipe including an evaporating region and a condensing region; and a tube bundle configured to wrap around the condensing region of the heat pipe and including one or more adjacent, parallel tubes, each tube forming a helix that is coaxial to the heat pipe.

A container for transporting a reactor is disclosed. The container includes a loop thermosiphon including a chamber, a heat exchanger fluidically coupled to the chamber, and an actuator including an unactuated state and an actuated state. The actuator is configured to automatically transition to the actuated state. The transition is based on an event occurring within the reactor. A working medium is configured to remove heat from the reactor in the actuated state.

A nuclear reactor core mechanical support bracket is disclosed. The support bracket includes a housing, a spring disposed internally within the housing, a shaft slidingly disposed within the housing, a shaft travel pin, and a flange. The shaft is configured to engage the spring to compress and decompress the spring as the shaft travels in and out of the housing. The shaft travel pin controls the travel of the shaft. The flange is configured to mount the nuclear reactor core mechanical support bracket to a canister of a nuclear reactor. The shaft includes an inset configured to interface with a nuclear reactor core component.

Heat pipes and methods of forming heat pipes, such as for use in nuclear reactor systems, are described herein. A representative method of forming a heat pipe includes forming a first wicking structure from a first material and forming a second wicking structure on the first wicking structure. Forming the second wicking structure can include mixing a second material and a third material, and heating the mixture of the second material and the third material to a temperature (a) less than a melting temperature of the second material and (b) greater than a melting temperature of the third material to melt the third material. The method can further include cooling the mixture of the second material and the third material to below the melting temperature of the third material such that the third material solidifies to bond together a plurality of particles of the second material into a porous structure.

Heat pipes and methods of forming heat pipes, such as for use in nuclear reactor systems, are described herein. A representative method of forming a heat pipe includes forming a first wicking structure from a first material and forming a second wicking structure on the first wicking structure. Forming the second wicking structure can include mixing a second material and a third material, and heating the mixture of the second material and the third material to a temperature (a) less than a melting temperature of the second material and (b) greater than a melting temperature of the third material to melt the third material. The method can further include cooling the mixture of the second material and the third material to below the melting temperature of the third material such that the third material solidifies to bond together a plurality of particles of the second material into a porous structure.

Power generation systems, such as nuclear power generation systems, are described herein. A representative power generation system includes a heat source, a heat pipe, and a thermophotovoltaic cell. The heat pipe includes a first region and a second region. The first region is positioned to absorb heat from the heat source, and the second region is positioned to radiate at least a portion of the absorbed heat away from the heat pipe as thermal radiation. The thermophotovoltaic cell is positioned to receive the thermal radiation from the second region of the heat pipe and to convert at least a portion of the thermal radiation to electrical energy. The power generation system can further include another heat pipe positioned to remove waste heat from the thermophotovoltaic cell.

Power generation systems, such as nuclear power generation systems, are described herein. A representative power generation system includes a heat source, a heat pipe, and a thermophotovoltaic cell. The heat pipe includes a first region and a second region. The first region is positioned to absorb heat from the heat source, and the second region is positioned to radiate at least a portion of the absorbed heat away from the heat pipe as thermal radiation. The thermophotovoltaic cell is positioned to receive the thermal radiation from the second region of the heat pipe and to convert at least a portion of the thermal radiation to electrical energy. The power generation system can further include another heat pipe positioned to remove waste heat from the thermophotovoltaic cell.

A system that measures the temperature distribution of the reactor coolant flowing through the hot leg or cold leg pipes by measuring the speed of sound time delay. This concept uses radiation hardened and temperature tolerant ultrasonic signal drivers based on vacuum micro-electronic technology. The system employs ultrasonic signals propagated through water, and relies on the characteristic that the speed of sound changes as the density and temperature of the water changes. Thus, a measured difference in the speed of sound in water may be directly correlated to a temperature change of the water.

A nuclear reactor core mechanical support bracket is disclosed. The support bracket includes a housing, a spring disposed internally within the housing, a shaft slidingly disposed within the housing and to engage the spring to compress and decompress the spring as the shaft travels in and out of the housing, a shaft travel pin to control the travel of the shaft, and a flange to mount the support bracket to a canister of a nuclear reactor. The shaft includes an inset configured to interface with a nuclear reactor core component.