A system and method for storing multiple canisters containing high level waste below grade that afford adequate ventilation of the spent fuel storage cavity. In one aspect, the invention is a ventilated system for storing high level waste emitting heat, the system comprising: an air-intake shell forming an air-intake cavity; a plurality of storage shells, each storage shell forming a storage cavity; a lid positioned atop each of the storage shells; an outlet vent forming a passageway between an ambient environment and a top portion of each of the storage cavities; and a network of pipes forming hermetically sealed passageways between a bottom portion of the air-intake cavity and at least two different openings at a bottom portion of each of the storage cavities such that blockage of a first one of the openings does not prohibit air from flowing from the air-intake cavity into the storage cavity via a second one of the openings.

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 transfer cask system for cooling spent nuclear fuel during the transfer from a spent nuclear fuel pool to a storage or transfer cask is disclosed. A canister containing spent nuclear fuel is inserted into a transfer cask. The transfer cask includes spacing components which define an annular region between the transfer cask and the canister. The transfer cask includes air inlets near a bottom end that permit air to flow through the defined annular region and exit at the open top of the transfer cask, thereby cooling the fuel within the canister. The transfer cask further comprises a neutron shield configured to absorb additional heat and shield radiation that may be generated within the canister. The transfer cask includes a transfer door that can open and close and has support rails that can support a spent nuclear fuel canister located in the transfer cask.

A transfer cask system for cooling spent nuclear fuel during the transfer from a spent nuclear fuel pool to a storage or transfer cask is disclosed. A canister containing spent nuclear fuel is inserted into a transfer cask. The transfer cask includes spacing components which define an annular region between the transfer cask and the canister. The transfer cask includes air inlets near a bottom end that permit air to flow through the defined annular region and exit at the open top of the transfer cask, thereby cooling the fuel within the canister. The transfer cask further comprises a neutron shield configured to absorb additional heat and shield radiation that may be generated within the canister. The transfer cask includes a transfer door that can open and close and has support rails that can support a spent nuclear fuel canister located in the transfer cask.

A nuclear fuel storage system includes an outer canister and fuel basket positioned therein. The basket is formed by orthogonally arranged and interlocked slotted plates which collectively define exterior side surfaces of the basket and a grid array of open cells each configured to hold a fuel assembly. At least some slotted plates comprise cantilevered plate extensions protruding laterally beyond the side surfaces of the basket to define various shaped peripheral gaps between the basket and canister. The plate extensions are configured to engage the shell of the canister. Vertically elongated reinforcement members are inserted in the peripheral gaps and fixedly coupled to the basket. Reinforcement members may comprise elongated reinforcement plates and/or tubular shimming members which may be fixedly coupled to the slotted plate extensions. The reinforcement members structurally strengthen the fuel basket. The plate extensions further act as fins to enhance heat dissipation from the basket.

A method of handling spent nuclear fuel assemblies immerses the spent nuclear fuel assemblies in water in a relatively short time period when compared to traditional methods. A spent nuclear fuel assembly is removed from a nuclear reactor, an inert gas is applied to the fuel assembly, moisture content in the inert gas is gradually increased as it is applied to the fuel assembly, and the fuel assembly is immersed in water. The fuel assembly is immersed relatively quickly, within about 2 hours or less, which improves safety and allows normal processing and handling equipment to care for the fuel assembly. The fuel assembly may then be loaded into a cask for long-term storage and/or disposal.

A method of handling spent nuclear fuel assemblies immerses the spent nuclear fuel assemblies in water in a relatively short time period when compared to traditional methods. A spent nuclear fuel assembly is removed from a nuclear reactor, an inert gas is applied to the fuel assembly, moisture content in the inert gas is gradually increased as it is applied to the fuel assembly, and the fuel assembly is immersed in water. The fuel assembly is immersed relatively quickly, within about 2 hours or less, which improves safety and allows normal processing and handling equipment to care for the fuel assembly. The fuel assembly may then be loaded into a cask for long-term storage and/or disposal.

To provide a containment cask for storage or transport of radioactive material, without employing a homogenization treatment. Pouring a molten lead between an inner shell 2 and an intermediate shell 3 to serve as a gamma ray shielding material, allowing the lead to cool, and subsequently, filling either one or both of a first void layer 9a formed at a boundary between the inner shell 2 and the poured lead 5a or a second void layer 9b formed at a boundary between the intermediate shell 3 and the poured lead 5a, using a low melting point metal 10 in a closely adhering state. To provide the cask 1 with a good heat-dissipating effect, by filling the void layers 9a, 9b that prevent the cask 1 from dissipating heat, with the low melting point metal 10 that has a superb thermal conductivity.

To provide a containment cask for storage or transport of radioactive material, without employing a homogenization treatment. Pouring a molten lead between an inner shell 2 and an intermediate shell 3 to serve as a gamma ray shielding material, allowing the lead to cool, and subsequently, filling either one or both of a first void layer 9a formed at a boundary between the inner shell 2 and the poured lead 5a or a second void layer 9b formed at a boundary between the intermediate shell 3 and the poured lead 5a, using a low melting point metal 10 in a closely adhering state. To provide the cask 1 with a good heat-dissipating effect, by filling the void layers 9a, 9b that prevent the cask 1 from dissipating heat, with the low melting point metal 10 that has a superb thermal conductivity.

Sealed containers for radioactive material are presented herein. A sealed container forms an interior envelope for housing a radioactive material and prevents escape of the radioactive material into a surrounding environment. The sealed container provides a diffusion window for gaseous decay products to escape at a particular diffusion rate. In one example, an apparatus, comprises a container forming a sealed interior envelope for a radioactive material. The container has an aperture covered by a window material, and properties of the window material are selected to provide for diffusion of at least one gas produced by radioactive decay of the radioactive material.