Patent Number: 
Section: claims

1. A system for use in shutting down a nuclear reactor, the system comprising:a housing defining a region therein sealed from an ambient environment;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 comprising a material having a predetermined melting point;a neutron absorbing material disposed within the first compartment; anda dispersion mechanism disposed within the region, the dispersion mechanism structured to actively encourage the neutron absorbing material from the first compartment into the second compartment,wherein the system is positioned relative to a core of the nuclear reactor such that the first compartment is positioned outside of the core and the second compartment is disposed within the core, and wherein the dispersion mechanism comprises a porous matrix structure disposed in the second compartment. 2. The system of claim 1, wherein the predetermined melting point of the material is around 8000 C. 3. The system of claim 1, wherein the gate member comprises a number of heater coils embedded in the material that are structured to melt the material upon actuation by an electrical current. 4. The system of claim 1, wherein the neutron absorbing material comprises a phase change material. 5. The system of claim 4, wherein the phase change material comprises at least one of an indium/cadmium alloy, lithium, or boron oxide. 6. A system for use in shutting down a nuclear reactor, the system comprising:a housing defining a region therein sealed from an ambient environment;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 comprising a material having a predetermined melting point;a neutron absorbing material disposed within the first compartment; anda dispersion mechanism disposed within the region, the dispersion mechanism structured to encourage the neutron absorbing material from the first compartment into the second compartment,wherein the neutron absorbing material comprises a phase change material, and wherein the dispersion mechanism comprises a porous matrix structure disposed in the second compartment. 7. The system of claim 6, wherein the second compartment is held under vacuum. 8. The system of claim 6, wherein the porous matrix structure is formed from one or more metals. 9. The system of claim 6, wherein the porous matrix structure is formed from one or more ceramic materials. 10. The system of claim 1, wherein the neutron absorbing material comprises a solid material. 11. The system of claim 10, wherein the dispersion mechanism comprises a number of springs disposed in the first compartment. 12. The system of claim 1, further comprising:a second gate member disposed within the region in a manner such that the second gate member further segregates the region into a third compartment isolated from the second compartment by a second gate member comprising another material having a predetermined melting point; anda neutron absorbing material disposed within the first compartment. 13. A nuclear reactor comprising:a core structured to house nuclear reactions; anda system for use in shutting down the nuclear reactor, the system comprising:a housing defining a region therein sealed from an ambient environment;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 comprising a material having a predetermined melting point;a neutron absorbing material disposed within the first compartment; anda dispersion mechanism disposed within the region, the dispersion mechanism structured to encourage the neutron absorbing material from the first compartment into the second compartment,wherein the system is positioned relative to the core such that the first compartment is positioned outside of the core and the second compartment is disposed within the core, and wherein the dispersion mechanism comprises a porous matrix structure disposed in the second compartment. 14. A method of providing a system for use in ceasing nuclear reactions within a core of a nuclear reactor, the method comprising positioning a system for use in shutting down the nuclear reactor, the system comprising: a housing defining a region therein sealed from an ambient environment; 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 comprising a material having a predetermined melting point; 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, wherein positioning the system comprises positioning the housing with respect to the core such that the first compartment is positioned outside of the core and the second compartment is disposed within the core, and wherein the dispersion mechanism comprises a porous matrix structure disposed in the second compartment.