A cooling air amount adjustment device of a concrete cask is provided. The device includes at least one of an air outlet port opening level adjustment mechanism and an air inlet port opening level adjustment mechanism which are adapted to automatically perform adjustment to reduce a flow rate of a cooling air when a temperature of the cooling air at an air outlet port is lower than an adjustment reference temperature, and adjustment to increase the flow rate of the cooling air so as to restore the flow rate of the cooling air when the temperature of the cooling air at the air outlet port is higher than the adjustment reference temperature.

A cooling air amount adjustment device of a concrete cask is provided. The device includes at least one of an air outlet port opening level adjustment mechanism and an air inlet port opening level adjustment mechanism which are adapted to automatically perform adjustment to reduce a flow rate of a cooling air when a temperature of the cooling air at an air outlet port is lower than an adjustment reference temperature, and adjustment to increase the flow rate of the cooling air so as to restore the flow rate of the cooling air when the temperature of the cooling air at the air outlet port is higher than the adjustment reference temperature.

A nuclear waste fuel storage system includes an unventilated cask including inner and outer shells, an annular space between the shells containing radiation shielding, and sealed baseplate. Threaded anchor bosses are affixed to the top end of the cask. A heavy free-floating radiation shielding lid is loosely coupled the top end of the cask in a movable manner via the anchor bosses by bolt assemblies which loosely secure the lid to the cask. An internal cavity of the cask which holds a nuclear waste fuel canister is sealed by an annular gasket compressed between the lid and cask, thereby forming a gas tight pressure vessel operable to retain internal pressures exceeding atmospheric. During a cask overpressurization condition, the lid automatically moves between a normal downward sealed position on the cask to an installer-adjustable raised relief position ajar from the cask to relieve excess pressure to atmosphere.

Casks shield materials and passively remove heat via heat transport paths from deep inside to outside the cask. The transport path may be heat pipes and conductive rods that are non-linear so that radiation is always shielded by the cask. A damper may surround an end of the heat transport path to control heat loss from the cask. A jacket of fluid or meltable material that conducts heat by convection may surround stored materials ensure an even temperature within the cask, and the heat transport path may absorb heat from the jacket. Casks are useable to safely store, transport, and dispose of any sensitive or heat-generating material. Casks may be opened or closed to simultaneously load and offload materials at a consistent operating temperature provided by heaters in the cask.

Casks shield materials and passively remove heat via heat transport paths from deep inside to outside the cask. The transport path may be heat pipes and conductive rods that are non-linear so that radiation is always shielded by the cask. A damper may surround an end of the heat transport path to control heat loss from the cask. A jacket of fluid or meltable material that conducts heat by convection may surround stored materials ensure an even temperature within the cask, and the heat transport path may absorb heat from the jacket. Casks are useable to safely store, transport, and dispose of any sensitive or heat-generating material. Casks may be opened or closed to simultaneously load and offload materials at a consistent operating temperature provided by heaters in the cask.

A neutron absorbing insert for use in a fuel rack. In one aspect, the insert includes: a plate structure having a first wall and a second wall that is non-coplanar to the first wall; the first and second walls being formed by a single panel of a metal matrix composite having neutron absorbing particulate reinforcement that is bent into the non-coplanar arrangement along a crease; and a plurality of spaced-apart holes formed into the single panel along the crease prior to bending.

An apparatus for supporting radioactive fuel assemblies, such as spent nuclear fuel. In one aspect, the apparatus is in the form of a fuel rack having adjustable height pedestals. In another aspect, the apparatus is a canister including a first pressure vessel forming a first cavity and a second pressure vessel forming a second cavity, the first pressure vessel located in the second cavity of the second pressure vessel. An inner surface of the second pressure vessel may be in continuous surface contact with an outer surface of the first pressure vessel to form a dual-walled canister.

An apparatus for supporting radioactive fuel assemblies, such as spent nuclear fuel. In one aspect, the apparatus is in the form of a fuel rack having adjustable height pedestals. In another aspect, the apparatus is a canister including a first pressure vessel forming a first cavity and a second pressure vessel forming a second cavity, the first pressure vessel located in the second cavity of the second pressure vessel. An inner surface of the second pressure vessel may be in continuous surface contact with an outer surface of the first pressure vessel to form a dual-walled canister.

Embodiments of a thermal divider insert for a dry storage, spent nuclear fuel cask are disclosed. The thermal divider insert enables safe storage of the hazardous nuclear material when one or more air inlets have been fully or partially blocked to an extent that insufficient air flows into the air inlets and through the cask for adequate cooling of the hazardous nuclear material. In one embodiment, the cask comprises a metal canister having a top, bottom, and sidewall. The canister contains the hazardous nuclear material. A concrete overpack contains the metal canister with the hazardous nuclear material. The overpack has a top, bottom, and sidewall. The overpack has an inside surface that is spaced from an outer surface of the canister to create an annular region that permits flow of air between the surfaces for cooling the canister. One or more air inlets near the bottom of the overpack communicate air from an outside environment into the annular region. One or more outlet vents near the top of the overpack communicate air from the annular region to the outside environment. The thermal divider insert extends through a respective outlet vent and into the annular region and is designed to establish two separate and opposite air flows (i.e., inward and outward air flows) through the respective vent and the annular region when the overpack air inlets have been blocked. When not blocked in normal operation, the two air flows both flow upwardly through the annular region and outwardly from the vent.

Embodiments of a thermal divider insert for a dry storage, spent nuclear fuel cask are disclosed. The thermal divider insert enables safe storage of the hazardous nuclear material when one or more air inlets have been fully or partially blocked to an extent that insufficient air flows into the air inlets and through the cask for adequate cooling of the hazardous nuclear material. In one embodiment, the cask comprises a metal canister having a top, bottom, and sidewall. The canister contains the hazardous nuclear material. A concrete overpack contains the metal canister with the hazardous nuclear material. The overpack has a top, bottom, and sidewall. The overpack has an inside surface that is spaced from an outer surface of the canister to create an annular region that permits flow of air between the surfaces for cooling the canister. One or more air inlets near the bottom of the overpack communicate air from an outside environment into the annular region. One or more outlet vents near the top of the overpack communicate air from the annular region to the outside environment. The thermal divider insert extends through a respective outlet vent and into the annular region and is designed to establish two separate and opposite air flows (i.e., inward and outward air flows) through the respective vent and the annular region when the overpack air inlets have been blocked. When not blocked in normal operation, the two air flows both flow upwardly through the annular region and outwardly from the vent.