A passive nuclear reactor control device. The passive nuclear reactor control device comprises a sealed chamber, which comprises a reservoir and a tube in fluid communication with the reservoir. A molten salt is within the sealed chamber, the molten salt being a eutectic mixture of a monovalent metal halide, and a fluoride or chloride of one or more lanthanides and/or a luoride or chloride of hafnium. A gas is within the sealed chamber, and the gas does not react with the molten salt.

A passive nuclear reactor control device. The passive nuclear reactor control device comprises a sealed chamber, which comprises a reservoir and a tube in fluid communication with the reservoir. A molten salt is within the sealed chamber, the molten salt being a eutectic mixture of a monovalent metal halide, and a fluoride or chloride of one or more lanthanides and/or a luoride or chloride of hafnium. A gas is within the sealed chamber, and the gas does not react with the molten salt.

A nuclear reactor controlled by moving a liquid fuel between a reservoir and chambers in the core is provided. No pumps or moving parts within the reactor vessel are needed to move the fuel. The control system moves the liquid fuel between the core and the reservoir by moving a separate control gas. It can monitor the internal state of the core through the control connections. The fuel chamber is shaped so that evolved gases escape the core and can be collected at the control connections. The core reverts to a safe state on power failure.

A nuclear reactor controlled by moving a liquid fuel between a reservoir and chambers in the core is provided. No pumps or moving parts within the reactor vessel are needed to move the fuel. The control system moves the liquid fuel between the core and the reservoir by moving a separate control gas. It can monitor the internal state of the core through the control connections. The fuel chamber is shaped so that evolved gases escape the core and can be collected at the control connections. The core reverts to a safe state on power failure.

A nuclear reactor controlled by moving a liquid fuel between a reservoir and chambers in the core is provided. No pumps or moving parts within the reactor vessel are needed to move the fuel. The control system moves the liquid fuel between the core and the reservoir by moving a separate control gas. It can monitor the internal state of the core through the control connections. The fuel chamber is shaped so that evolved gases escape the core and can be collected at the control connections. The core reverts to a safe state on power failure.

A nuclear reactor controlled by moving a liquid fuel between a reservoir and chambers in the core is provided. No pumps or moving parts within the reactor vessel are needed to move the fuel. The control system moves the liquid fuel between the core and the reservoir by moving a separate control gas. It can monitor the internal state of the core through the control connections. The fuel chamber is shaped so that evolved gases escape the core and can be collected at the control connections. The core reverts to a safe state on power failure.

A stationary control rod that controls overall nuclear reactivity and axial reactivity distribution of a fuel assembly, such that power level and axial power distribution within the fuel assembly is controlled without the need for movable control rods and associated hardware. The device uses magnetic fields to control the concentration and distribution of a magneto-rheological fluid containing a material with a very high neutron capture cross section, contained in one or more enclosed thimbles placed within existing thimbles in a fuel assembly. The magnetic fields are generated from electricity produced from interactions of the radiation particles within the core, or supplied using electrical cables that attach to fuel assembly top nozzles. The electricity drives a device that encloses associated wire coil assemblies that surround different axial regions of a tube that contains the magneto-rheological fluid.

A stationary control rod that controls overall nuclear reactivity and axial reactivity distribution of a fuel assembly, such that power level and axial power distribution within the fuel assembly is controlled without the need for movable control rods and associated hardware. The device uses magnetic fields to control the concentration and distribution of a magneto-rheological fluid containing a material with a very high neutron capture cross section, contained in one or more enclosed thimbles placed within existing thimbles in a fuel assembly. The magnetic fields are generated from electricity produced from interactions of the radiation particles within the core, or supplied using electrical cables that attach to fuel assembly top nozzles. The electricity drives a device that encloses associated wire coil assemblies that surround different axial regions of a tube that contains the magneto-rheological fluid.

A nuclear power system includes a reactor vessel that includes a reactor core mounted within a volume of the reactor vessel. The reactor core includes one or more nuclear fuel assemblies configured to generate a nuclear fission reaction. The nuclear power system further includes a containment vessel sized to enclose the reactor vessel such that an open volume is defined between the containment vessel and the reactor vessel. A boron injection system is positioned in the open volume of the containment vessel and includes an amount of boron sufficient to stop the nuclear fission reaction or maintain the nuclear fission reaction at a sub-critical state. The boron injection system is positioned to deliver the amount of boron into the open volume.

A nuclear power system includes a reactor vessel that includes a reactor core mounted within a volume of the reactor vessel. The reactor core includes one or more nuclear fuel assemblies configured to generate a nuclear fission reaction. The nuclear power system further includes a containment vessel sized to enclose the reactor vessel such that an open volume is defined between the containment vessel and the reactor vessel. A boron injection system is positioned in the open volume of the containment vessel and includes an amount of boron sufficient to stop the nuclear fission reaction or maintain the nuclear fission reaction at a sub-critical state. The boron injection system is positioned to deliver the amount of boron into the open volume.