A nuclear power system includes a reactor vessel that includes a reactor core that includes nuclear fuel assemblies configured to generate a nuclear fission reaction. A representative nuclear power system further includes a riser positioned above the reactor core and a primary coolant flow path that extends from a bottom portion of the reactor vessel, through the reactor core, and through an annulus between the riser and the reactor vessel. A primary coolant circulates through the primary coolant flow path to receive heat from the nuclear fission reaction and release the heat to a power generation system configured to generate electric power. The nuclear power system further includes a control rod assembly system positioned in the reactor vessel and configured to position control rods in only two discrete positions.

A system for use in shutting down a nuclear reactor includes a housing that defines a region therein sealed from an ambient environment and a gate member disposed within the region in a manner such that the gate member segregates the region into a first compartment and a second compartment isolated from the first compartment. The gate member is formed from a material having a predetermined melting point. The system further includes a neutron absorbing material disposed within the first compartment and a dispersion mechanism disposed within the region. The dispersion mechanism structured to encourage the neutron absorbing material from the first compartment into the second compartment.

A system for use in shutting down a nuclear reactor includes a housing that defines a region therein sealed from an ambient environment and a gate member disposed within the region in a manner such that the gate member segregates the region into a first compartment and a second compartment isolated from the first compartment. The gate member is formed from a material having a predetermined melting point. The system further includes a neutron absorbing material disposed within the first compartment and a dispersion mechanism disposed within the region. The dispersion mechanism structured to encourage the neutron absorbing material from the first compartment into the second compartment.

A molten salt reactor is disclosed. In some embodiments, the molten salt reactor comprises a containment vessel; a molten salt chamber disposed within the containment vessel; a molten salt mixture disposed within the molten salt chamber; and a heat exchange system at least partially disposed within the molten salt chamber. In some embodiments, the molten salt reactor comprises one or more of a shutdown mechanism, a thermally activated failsafe mechanism, and/or a passive reactivity control system. The shutdown mechanism, for example, may be coupled with the molten salt chamber, the shutdown mechanism comprising a material that when inserted into the molten salt chamber will inhibit fission reactions within the molten salt mixture. The thermally activated failsafe mechanism, for example, may be coupled with the molten salt chamber, the thermally activated failsafe mechanism passively inhibits fission reactions within the molten salt mixture.

The invention relates to a method for eliminating neutrons from fission, fusion or aneutronic nuclear reactions in a reactor, in particular in a laser-driven nuclear fusion reactor which operates with hydrogen and the boron-11 isotope, in which method at least some moderated neutrons are made to undergo a nuclear reaction with tin. As a result of the nuclear reactions with tin, the neutrons convert the tin nuclei into stable nuclei having a higher atomic weight resulting from neutron capture. The invention also relates to a reactor which is designed for energy conversion by means of fission, fusion or aneutronic nuclear reactions and for generating electric energy, wherein the reactor contains a neutron elimination device which contains tin and is arranged such that at least some moderated neutrons are made to undergo a nuclear reaction with the tin.

The invention relates to a method for eliminating neutrons from fission, fusion or aneutronic nuclear reactions in a reactor (100), in particular in a laser-driven nuclear fusion reactor (100) which operates with hydrogen and the boron-11 isotope, in which method at least some moderated neutrons are made to undergo a nuclear reaction with tin (11). As a result of the nuclear reactions with tin, the neutrons convert the tin nuclei into stable nuclei having a higher atomic weight resulting from neutron capture. The invention also relates to a reactor (100) which is designed for energy conversion by means of fission, fusion or aneutronic nuclear reactions and for generating electric energy, wherein the reactor contains a neutron elimination device (50) which contains tin and is arranged such that at least some moderated neutrons are made to undergo a nuclear reaction with the tin.

A system for use in shutting down a nuclear reactor includes a housing that defines a region therein sealed from an ambient environment and a gate member disposed within the region in a manner such that the gate member segregates the region into a first compartment and a second compartment isolated from the first compartment. The gate member is formed from a material having a predetermined melting point. The system further includes a neutron absorbing material disposed within the first compartment and a dispersion mechanism disposed within the region. The dispersion mechanism structured to encourage the neutron absorbing material from the first compartment into the second compartment.

A system for use in shutting down a nuclear reactor includes a housing that defines a region therein sealed from an ambient environment and a gate member disposed within the region in a manner such that the gate member segregates the region into a first compartment and a second compartment isolated from the first compartment. The gate member is formed from a material having a predetermined melting point. The system further includes a neutron absorbing material disposed within the first compartment and a dispersion mechanism disposed within the region. The dispersion mechanism structured to encourage the neutron absorbing material from the first compartment into the second compartment.

An absorber cluster for a nuclear reactor includes at least a first absorber assembly and a second absorber assembly. Each absorber assembly respectively comprises neutron absorbing elements. Absorber elements of each of the first absorber assembly and the second absorber assembly are made from the same material or the same combination of materials selected from the group of neutron absorbing materials consisting of a first europium hafnate, a second europium hafnate, a first samarium hafnate, a second samarium hafnate, hafnium carbide, and samarium hexaboride. The first europium hafnate and the second europium hafnate have different compositions. The first samarium hafnate and the second samarium hafnate have different compositions. The absorber elements of the first absorber assembly have a cross-sectional structure different to that of the absorber elements of the second absorber assembly.

An absorber cluster for a nuclear reactor includes at least a first absorber assembly and a second absorber assembly. Each absorber assembly respectively comprises neutron absorbing elements. Absorber elements of each of the first absorber assembly and the second absorber assembly are made from the same material or the same combination of materials selected from the group of neutron absorbing materials consisting of a first europium hafnate, a second europium hafnate, a first samarium hafnate, a second samarium hafnate, hafnium carbide, and samarium hexaboride. The first europium hafnate and the second europium hafnate have different compositions. The first samarium hafnate and the second samarium hafnate have different compositions. The absorber elements of the first absorber assembly have a cross-sectional structure different to that of the absorber elements of the second absorber assembly.