Abstract: A control rod drive system (CRDS) for use in a nuclear reactor. In one embodiment, the system generally includes a drive rod mechanically coupled to a control rod drive mechanism (CRDM) operable to linearly raise and lower the drive rod along a vertical axis, a rod cluster control assembly (RCCA) comprising a plurality of control rods insertable into a nuclear fuel core, and a drive rod extension (DRE) releasably coupled at opposing ends to the drive rod and RCCA. The CRDM includes an electromagnet which operates to couple the CRDM to DRE. In the event of a power loss or SCRAM, the CRDM may be configured to remotely uncouple the RCCA from the DRE without releasing or dropping the drive rod which remains engaged with the CRDM and in position.

Abstract: A nuclear waste cask with impact protection includes impact limiters detachably coupled to opposite ends of the cask. Each impact limiter may comprise a deformable energy-absorbing perforated sleeve of cylindrical shape comprising an array of closely-spaced longitudinally elongated perforations. The perforations may comprise longitudinal passages having a circular cross-sectional shape in certain embodiments. The perforated sleeve may have an annular metallic body of monolithic unitary structure in which the perforations are formed and a central opening to receive the ends of the cask therein. When exposed to external impact forces such as created by dropping the cask, the perforations collapse inwards in the impact or crush zone to absorb the energy of fall while preventing or minimizing any forces transmitted to the cask to maintain the integrity of waste containment barrier.

Abstract: A container for storing and/or transporting spent nuclear fuel. The container includes a body that defines an internal cavity that holds the spent nuclear fuel and an outer surface. The outer surface has holes formed therein into which trunnions are positioned. The container can be lifted by a lift yoke by coupling the lift yoke to the trunnions. The trunnions may include first and second components such that the first component is slidable in its axial direction relative to the second component when a force that exceeds a threshold acts on the second component. Thus, the second component may be slidable between a protruded state in which a portion of the second component protrudes from the outer surface of the body and a retracted state in which the second component does not protrude from the outer surface of the body.

Abstract: 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.

Abstract: A module for storing high level radioactive waste includes an outer shell, having a hermetically closed bottom end, and an inner shell forming a cavity and being positioned inside the outer shell to form a space therebetween. At least one divider extends from the top to the bottom of the inner shell to create a plurality of inlet passageways through the space, each inlet passageway connecting to a bottom portion of the cavity. A plurality of inlet ducts each connect at least one of the inlet passageways and ambient atmosphere, and each includes an inlet duct cover affixed atop a surrounding inlet wall, the inlet wall being peripherally perforated. A removable lid is positioned atop the inner shell and has at least one outlet passageway connecting the cavity and the ambient atmosphere, the lid and the top of the inner shell being configured to form a hermetic seal therebetween.

Abstract: An impact amelioration system for nuclear fuel storage components in one embodiment includes a fuel storage canister and outer cask receiving the canister. The canister is configured for storing spent nuclear fuel or other high level radioactive waste. A plurality of impact limiter assemblies are disposed on the bottom closure plate of the cask at the canister interface. Each impact limiter assembly comprises an impact limiter plug frictionally engaged with a corresponding plug hole formed in the cask closure plate. The canister rests on tops of the plugs, which may protrude upwards beyond the top surface of the bottom closure lid. The plugs and holes may mating tapered and frictionally engaged surfaces. During a cask drop event, the canister drives the plugs deeper into the plug holes and elastoplastically deform to dissipate the kinetic impact energy and protect the structural integrity of the canister and its contents.

Abstract: 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.

Abstract: A system for preparing a container holding radioactive waste for dry storage. In one aspect, the invention can be a system for preparing a container having a cavity loaded with radioactive elements for dry storage, the system comprising: a gas circulation system comprising a condenser module, a desiccant module, and a gas circulator module; the gas circulation system configured to form a hermetically sealed closed-loop path when operably connected to the cavity of the container; and means for adding and removing the desiccant module as part of the hermetically sealed closed-loop path.

Abstract: A method of forming a sealed canister and a method of storing radioactive materials is provided. The method of forming includes placing a top plate on a top opening of a side wall, a bottom of the side wall being sealed to a base plate. The top plate includes a top surface with a top edge having a bevel and with a channel set in from the top edge. Finally, a weld is formed between the beveled top edge and the top opening of the side wall to seal the top plate to the side wall.

Abstract: Portable nuclear fuel cartridge comprising a unitary support structure and plurality of nuclear fuel assemblies that collectively form a nuclear fuel core. Control rod drive system for a nuclear reactor. A nuclear steam supply system having a shutdown system for removing residual decay heat generated by a nuclear fuel core. A nuclear reactor including a cylindrical body having an internal cavity, nuclear fuel core, and a shroud disposed in the cavity. A nuclear reactor cooling system with passive cooling capabilities operable during a loss-of-coolant accident (LOCA) without available electric power.

Abstract: A dry storage systems for radioactive nuclear waste materials may include a double-walled canister system. The canister system may include a canister having a tubular inner shell defining an internal cavity for storing nuclear waste material, a first lid sealably welded to a first end of the inner shell, a primary base plate defining a peripheral edge portion and having an annular closure flange, and an annular full thickness butt weld formed at an abutment joint between the annular closure flange and a second end of the inner shell. The inner shell, first lid, and first end closure may collectively define a sealed primary pressure retention barrier. A tubular outer shell may adjoin the inner shell. The outer shell may be welded to the canister to form a hermetically sealed secondary pressure retention barrier.

Abstract: An air-cooled condenser system for steam condensing applications in a power plant Rankine cycle includes an air cooled condenser having a plurality of interconnected modular cooling cells. A method for forming an axial flow baffle for a shell and tube heat exchanger includes providing a baffle workpiece, locating a centerpoint of a first axial flow tube aperture, drilling flow holes around the centerpoint of the flow aperture, and drilling a central tube hole at the centerpoint. A method of cooling high level waste includes surrounding a cask comprising an external surface and an internal storage cavity containing the high level radioactive waste which emits heat with a cooling water header; and discharging cooling water radially inwards from the cooling water header onto the external surface of the cask from the plurality of water dispensing outlets arranged on the cooling water header.

Abstract: A separable multi-component cask for spent nuclear fuel transport and storage includes a vertically elongated outer cylinder having a neutron radiation shielding composition and a vertically elongated inner cylinder having a gamma radiation blocking composition. The inner cylinder includes a cavity configured to hold a spent nuclear fuel canister. The inner cylinder is detachably mounted and nested inside a cavity of the outer cylinder and is separable therefrom during spent fuel cask loading operations in a staged manner. An air ventilation annulus formed between the first and second cylinders forms a heat removal passage to remove heat emitted by the radioactive canister when placed inside the second cylinder. A pair of removably coupled mating top flanges on the inner and outer cylinders supports and suspends the inner cylinder in a cantilevered manner, thereby allowing the directly heated inner cylinder to thermally expand to a greater degree than the outer cylinder.

Abstract: A method for heating primary coolant in a nuclear supply system in one embodiment includes filling a primary coolant loop within a reactor vessel and a steam generating vessel that are fluidly coupled together with a primary coolant, drawing a portion of the primary coolant from the primary coolant loop and into a start-up sub-system, heating the portion of the primary coolant to form a heated portion of the primary coolant, and injecting the heated portion of the primary coolant back into the primary coolant loop. The primary coolant may be heated to a no-load operating temperature.

Abstract: A system for storing nuclear fuel, the system including a storage rack and a bearing pad. The storage rack includes an array of cells, each cell configured to receive and store nuclear fuel rods, a base plate configured to support the array of cells, and a support structure configured to support the base plate and to allow cooling fluid to circulate under and up through apertures in the base plate. The bearing pad is coupled to the support structure and is configured to limit lateral movement of the storage rack independent from lateral movement of the bearing pad. The base plate defines a base plate profile in a horizontal plane of the base plate, and the bearing pad defines a bearing pad profile in the horizontal plane of the base plate, wherein the bearing pad profile extends outside of the base plate profile.

Abstract: A nuclear steam supply system having a start-up sub-system for heating a primary coolant. The nuclear steam supply system comprises a reactor vessel with core comprising nuclear fuel, and steam generating vessel fluidly coupled to the reactor vessel. A primary coolant loop formed within the reactor vessel and the steam generating vessel circulates primary coolant through the loop. A steam supply start-up sub-system is fluidly coupled to the primary coolant loop. The start-up sub-system is configured and operable to: (1) extract and receive a portion of the primary coolant from the primary coolant loop; (2) heat the portion of the primary coolant to form a heated portion of the primary coolant; and (3) inject the heated portion of the primary coolant back into the primary coolant loop.

Abstract: 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.

Abstract: A nuclear waste cask with impact protection includes impact limiters detachably coupled to opposite ends of the cask. Each impact limiter may comprise a deformable energy-absorbing perforated sleeve of cylindrical shape comprising an array of closely-spaced longitudinally elongated perforations. The perforations may comprise longitudinal passages having a circular cross-sectional shape in certain embodiments. The perforated sleeve may have an annular metallic body of monolithic unitary structure in which the perforations are formed and a central opening to receive the ends of the cask therein. When exposed to external impact forces such as created by dropping the cask, the perforations collapse inwards in the impact or crush zone to absorb the energy of fall while preventing or minimizing any forces transmitted to the cask to maintain the integrity of waste containment barrier.

Abstract: 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 themed 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.

Abstract: An underground ventilated system for storing nuclear waste materials. The system includes a storage module having an outer shell defining an internal cavity and an inner shell. A majority of the height of the outer shell may be disposed below grade. The outer shell may include a hermetically sealed bottom. First and second canisters are positioned in lower and upper portions within the cavity respectively in vertically stacked relationship. A centering and spacing ring assembly is interspersed between the first and second canisters to transfer the weight of the upper second canister to the lower first canister. The assembly may include centering lugs which laterally restrain the first and second canisters in case of a seismic event. A natural convection driven ventilated air system cools the canisters to remove residual decay heat to the atmosphere. In one non-limiting embodiment, the shells are made of steel.