Abstract: An automatically adjusting seismic restraint system for nuclear fuel storage in one embodiment comprises a free-standing first fuel storage component (FSC) configured to contain nuclear fuel, and a stationary second FSC configured to receive the first fuel storage component. An inter-body gap formed between the FSCs includes at least one seismic restraint assembly. The assembly includes a stationary wedge member fixedly coupled to the second FSC and a movable loose wedge member engaged with and supported in place by the stationary wedge member. The stationary wedge member defines an inclined load bearing surface slideably engaged with a mating inclined load bearing surface of the loose wedge member. During a seismic event or thermal expansion of the first FSC, the first FSC moves towards the second FSC which shrinks the inter-body gap and the loose wedge member is vertically displaced relative to the stationary wedge member while maintaining engagement therewith.

Abstract: A fuel rack for storing nuclear fuel in a fuel pool in one embodiment comprises a baseplate configured for placement in a fuel pool, and a cellular body coupled to the baseplate. The body comprises tightly-packed upwardly open cells which each hold a nuclear fuel assembly. In one embodiment, each cell may have a hexagonal cross-sectional configuration. The cells are each formed by angled cell walls and corners formed between adjoining cell walls. Adjacent cells are arranged to meet in corner-to-corner alignment. This produces triangular-shaped flux traps interspersed between the cells for reactivity control. In some embodiments, at least one peripheral side of the fuel rack has an undulating configuration defining a series of alternating peaks and valleys which nests with a complementary configured peripheral side of an adjacent fuel rack. This provides higher packing density of fuel racks and fuel assemblies in the fuel pool.

Abstract: An apparatus for supporting spent nuclear fuel including a plurality of wall plates arranged in an intersecting manner to define a basket apparatus extending along a longitudinal axis. The basket apparatus may include a plurality of fuel cells and a plurality of flux traps between adjacent fuel cells. A plurality of reinforcement members may be positioned in the flux traps and may extend between opposing ones of the wall plates that form the flux traps. Each of the wall plates may be a slotted wall plate. The slotted wall plates may be interlocked with one another to form the basket apparatus. Each of the slotted wall plates may include an upper edge, a lower edge, and a plurality of plate slots formed in each of the upper and lower edges. The plate slots of the slotted wall plates may receive intersecting slotted wall plates.

Abstract: A nuclear waste cask with impact protection includes impact limiters comprising deformable energy-absorbing perforated sleeves. An impact amelioration system for nuclear fuel storage components includes impact limiter assemblies at the bottom cask to canister interface including impact limiter plugs frictionally engaging corresponding plug holes formed in the cask closure plate. A nuclear waste fuel storage system includes an unventilated cask including a heavy free-floating radiation shielding lid loosely coupled the top end of the cask in a movable manner via the anchor bosses which provides cask over pressurization protection. A nuclear waste cask includes an axially elongated rectangular cuboid cask body having a cavity for holding nuclear waste materials and cask locking mechanism including first locking protrusions on the lid which are selectively interlockable with mating second locking protrusions on the cask body to lock the lid to the cask body.

Abstract: An induced draft air-cooled condenser for steam condensing applications includes a pair of inclined tube bundles defining a interior space therebetween in fluid communication with ambient air heated as it flows through the tube bundles. A fan supported above the interior space comprises rotatable fan blades disposed inside a cylindrical annular fan shroud. A drive mechanism operable to rotate the fan blades includes a motor operably coupled to the fan blades. The motor is supported inside the fan shroud and may be housed in a protective enclosure which may be insulated. A motor cooling system includes an air inlet duct fluidly coupled to ambient air outside the shroud and the enclosure. When the fan operates, cool ambient air is drawn via a vacuum formed by the fan through the duct to cool the motor. The air thus bypasses and is not heated by the tube bundles.

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: 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: A power generation system and related method for repowering a fossil-fueled power plant using a carbon-free nuclear steam supply system (NSSS) which replaces the existing fossil plant steam generator which burns fossil fuel such as coal, oil, or natural gas. The existing fossil plant energy conversion system including the turbine-generator (turbogenerator) and auxiliary components of the Rankine cycle is retained. The NSSS may include a small modular reactor (SMR) unit comprising a reactor vessel with nuclear fuel core and steam generator which receives heated primary coolant from the reactor to produce main steam to operate the Rankine cycle. The main steam output by the SMR unit is compressed in a steam compressor to increase its pressure to a level necessary to operate the turbogenerator. The compressor may be operated via a portion of the main steam. An intercooler of the compressor may be used for main steam reheating.

Abstract: A fuel rack comprises a base plate and vertically-extending hexagonal tubes. Each tube defines a cell. A top surface of the base plate forms a floor of each cell. Adjustable height pedestals can be connected to a bottom surface of the base plate. Each pedestal includes a tool engagement portion in a top surface of a peg. Rotation of the peg causes pedestal height adjustment. Each peg is aligned with a hole in a cell floor. A tool can extend through the hole to adjust the height of the pedestal. Vertically elongated spacing rods are positioned in gaps between adjacent hexagonal tubes to maintain the gaps. Each spacing rod is plug welded to a corner edge of three adjacent hexagonal tubes at a juncture via holes located in the corner edges of each of the three adjacent hexagonal tubes.

Abstract: A natural passively cooled ventilated cask includes a cavity which holds a canister containing heat and radiation emitting spent nuclear fuel assemblies. Cooling air inlet ducts draw ambient cooling air inwards into a lower portion of the cavity. The air heated by the canister flows upwards along the canister and is discharged from at least one air outlet duct formed by the cask lid to atmosphere via natural convective thermo-siphon flow. The air inlet ducts or at least one outlet duct in one embodiment may be fitted with an adjustable shutter plate which allows the flowrate of air entering the cask to be increased or decreased to maintain a predetermined canister maximum temperature limit selected in part to prevent the onset of stress corrosion cracking of the canister welds. Other embodiments may use a fixed orifice plate replaceable over time to maintain the minimum temperature.

Abstract: A container system for radioactive waste and method for using the same is provided. The system includes a canister configured for holding radioactive waste and a lid system. In one embodiment, the lid system comprises a two-part lid assembly including a confinement lid and a shielded lifting lid. The confinement lid is detachably mounted to the confinement lid. In use, the lifting lid supports the confinement lid for lifting and placement on the canister. The lifting lid further shields operators while the confinement lid is mounted to the canister. Thereafter, the lifting lid is removed and may be reused for confinement lid mountings on other canisters. In one embodiment, the confinement lid is bolted to the canister. The canister may be disposed in a protective overpack for transport and storage.

Abstract: A passively cooled stackable nuclear waste storage system includes an at least partially below grade cavity enclosure container (CEC) and above grade cask. Each vessel includes a cavity holding a nuclear waste canister containing spent nuclear fuel or other high-level radioactive wastes. The CEC is founded on a below grade concrete base pad and cask is mounted on an above-grade concrete top pad in a vertically stacked arrangement. The upper cask comprises a perforated baseplate which establishes fluid communication between cavities of both casks and is configured to prevent radiation shine. One or both vessels include air inlets which draw ambient cooling air into their respective cavities for cooling the nuclear waste. Air heated in the lower CEC rises into the upper cask through the baseplate where it mixes with air drawn into the cask and is returned to atmosphere. The system increases storage capacity of new or existing facilities.

Abstract: A radioactive nuclear waste storage system includes a cask comprising a hermetically sealed internal cavity configured for holding the waste such as spent nuclear fuel submerged in an inventory of water. One or more pressure surge capacitors disposed inside the cask include a vacuum cavity evacuated to sub-atmospheric conditions prior to storage of fuel in the cask. At least one rupture disk seals a vacuum chamber inside each capacitor. Each rupture disk is designed and constructed to burst at a predetermined burst pressure level occurring inside the cask external to the capacitor. This allows excess cask pressure occurring during a high pressure excursion resulting from abnormal operating conditions to bleed into capacitor, thereby returning the pressure inside the cask to acceptable levels. In one embodiment, the capacitors are located in peripheral regions of the cask cavity adjacent to the circumferential wall of the cask body.

Abstract: An impact amelioration apparatus and system comprising a stationary impact limiter containing a deformable impact-cushioning material that can be used as a kinetic energy-absorbing target against a free falling radioactive waste-laden vessel such as a nuclear waste storage and/or transport cask. In one embodiment, the cushioning material may be one or more layers of pervious concrete encased in a metal outer container, which may be hermetically-sealed in some embodiments. The pervious concrete is crushable upon impact by an accidentally dropped free-falling cask to safely decelerate the cask while preserving the structural radiation containment envelope of the cask to prevent release of radiation to the ambient environment. The stationary impact limiter may located on a support surface in an equipment loading area of a nuclear facility, such as a nuclear power generation plant, beneath an overhead lifting apparatus used to move equipment such as casks into and out of the facility.

Abstract: A green boiler includes a thermal energy storage vessel containing a captive bed of a thermal mass composition operable to store thermal energy, an array of heaters embedded in the mass, and at least one heat exchanger comprising a tube bundle. The heaters in one embodiment may be electric and coupled to an electric power source to heat the thermal mass. The tube bundle comprises tubes embedded in the thermal mass composition which are configured to convey heat transfer fluid (e.g., water or other) through a tube-side of the tubes. In operation, the heat transfer fluid is heated by absorbing stored thermal energy from the thermal mass composition. The thermal mass composition may be heated by power extracted from the power grid during off-peak demand periods in some embodiments. The vessel may produce heated water or steam for district heating, or steam for power generation or industrial uses.

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 system for transporting radioactive materials which may include a containment vessel, a thermal shield, and an impact limiter. The containment vessel may include a vessel body having a storage cavity for receiving radioactive materials, a lid coupled to an upper portion of the vessel body to enclose a top end of the storage cavity, and a lid seal such as a gasket positioned between the lid and the upper portion of the vessel body. The thermal shield may be positioned over the lid. The first impact limiter may be positioned over the thermal shield. The thermal shield may be resistant to high temperatures and may help to protect the integrity of the lid seal when the system is subjected to high temperatures, such as during a fire condition.

Abstract: A containment enclosure for shielding an outer cask containing an inner canister loaded with nuclear waste such as spent fuel rods. The enclosure includes a lower base portion at least partially embedded in a concrete pad and an upper radiation shielding portion defined by a shield jacket coupled to and supported by the lower base portion at a circumferential joint. Cavities of the base and shielding portions collectively define a contiguous containment space for the cask. A portion of the cask resides in each of the base and shielding portions which completely enclose and shield the cask to minimize radiation dosage of personnel in the environment surrounding the cask. The cask is cooled by a natural convectively-driven ambient cooling air ventilation system including air inlets at the circumferential joint of the enclosure. The concrete pad may be part of a spent nuclear fuel storage installation comprising plural cask containment enclosures.

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.