Abstract: A passively cooled stackable nuclear waste storage system may include a pair of vertically stacked radiation-shielded nuclear waste storage casks. Each cask has a cavity which holds a nuclear waste canister containing spent nuclear fuel or other high-level radioactive wastes. The lower cask may be founded on an above-grade concrete pad. The upper cask is vertically stacked on and detachably coupled to the lower cask. 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 casks may include air inlet vents configured to draw ambient ventilation air into each respective cask cavity for cooling the nuclear waste. In operation, air is drawn inward into each cask cavity independently. Air heated in the lower cask rises into the upper cask where it mixes with air drawn into the upper cask and is returned to atmosphere.

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 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 vertical bundle air-cooled heat exchanger, a finned tube assembly for an air cooled condenser and method for forming the same, and a system for removing thermal energy generated by radioactive materials. In one aspect, an air cooled condenser sized for industrial and commercial application includes an inlet steam distribution header for conveying steam, a condensate outlet header for conveying condensate, an array of tube bundles each having a plurality of finned tube assemblies having a bare steel tube with an exposed outer surface and a set of aluminum fins brazed directly onto the tube by a brazing filler metal. The steel tubes may be spaced apart by the aluminum fins and have an inlet end fluidly coupled to the inlet steam distribution header and an outlet end fluidly coupled to the outlet header. A forced draft fan may be arranged to blow air through the tube bundles.

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 hybrid solar energy power generation system includes a thermal energy storage (TES) vessel containing a thermal mass composition operable to store thermal energy, a concentrated solar power (CSP) system, and a photovoltaic (PV) power system. The CSP system heats a first working fluid flowing in first closed flow loop via a solar collector. The heated first working fluid recirculates through the TES vessel to heat the TM composition. The PV power system generates electricity which can be delivered directly to the electric power grid or alternatively when grid demand drops energizes can electric heaters to supplement heating the first working fluid. This increases the temperature and enthalpy of the first working fluid to store additional thermal energy in the TM composition. The TES vessel is operable to heat a second working fluid to produce steam usable for industrial processes, district heating, or to power a Rankine power generation cycle.

Abstract: A nuclear waste cask in one embodiment includes an axially elongated cask body defining a longitudinally-extending opening forming an entrance to an internal storage cavity of the cask configured for holding radioactive nuclear waste materials. A closure lid detachably coupled to the cask body at the top opening seals the cavity. A cask locking mechanism includes a plurality of first locking protrusions spaced apart on the lid which are selectively interlockable with a plurality of second locking protrusions spaced apart on the cask body to lock the lid to the cask body. The first locking protrusions may be disposed on slideable locking bars moveable between locked and unlocked positions while the lid remains stationary on the cask body. Hydraulic or pneumatic actuators may be used to change position of the locking bars. The cask and lid may include other features such as impact absorbers and lifting elements.

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 overpressurization 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: 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 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: A hybrid power generation system in one embodiment comprises a green boiler containing a thermal mass composition operable to store thermal energy, a solar energy collection system which absorbs solar energy to heat a first working fluid and in turn the thermal mass composition, and a power generation system comprising a steam turbine coupled to an electric generator to produce electricity and a nuclear steam supply system which convert a second working fluid comprising water from liquid to steam. Steam output by the nuclear steam supply system flows through the green boiler and is heated by absorbing heat from the thermal mass composition to increase the enthalpy of the steam and concomitantly electric power output from the turbine-generator. The nuclear steam supply system and green boiler may be retrofit to replace existing fossil fuel steam generation systems while retaining the energy conversion part of the fossil power plant.

Abstract: A passively cooled stackable nuclear waste storage system may include a pair of vertically stacked radiation-shielded nuclear waste storage casks. Each cask has a cavity which holds a nuclear waste canister containing spent nuclear fuel or other high-level radioactive wastes. The lower cask may be founded on an above-grade concrete pad. The upper cask is vertically stacked on and detachably coupled to the lower cask. 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 casks may include air inlet vents configured to draw ambient ventilation air into each respective cask cavity for cooling the nuclear waste. In operation, air is drawn inward into each cask cavity independently. Air heated in the lower cask rises into the upper cask where it mixes with air drawn into the upper cask and is returned to atmosphere.

Abstract: A system uses nuclear fuel decay heat to heat a building. The system includes a plurality of fluidly-isolated but thermally-coupled heat removal flow loops that operate in tandem to absorb thermal energy originating from water in a spent nuclear fuel pool located in the building. The thermal energy is transferred in a cascading manner from a first flow loop to a final flow loop which has an external heat sink located outside the building. The heat sink can transfer heat to an ambient environment. A controller regulates the intake and flowrate of cooling water into the final flow loop. The controller also monitors fuel pool water temperature and air temperature inside the building. The controller can regulate the flowrate to maintain a predetermined building air temperature by allowing the fuel pool water temperature to rise to near a maximum permissible limit.

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: An automated welding system for sealing high level radioactive waste containers in the field at the nuclear plant site. The system includes a programmable portable robotic welder comprising a multi-jointed articulating robotic arm. A welding head operable to form a weld is mounted to the arm. Operation of the robotic welder and ancillary components is controlled by a programmable controller which implements a welding plan. In one embodiment, a circumferentially-extending lid-to-shell hermetic seal weld may be formed by the robotic welder. The weld is completed in multiple welding passes through the weld joint between the lid and shell guided by an automated joint tracking sensor linked to the controller. The highly portable robotic welder is detachably mountable on the lid to perform the welding. An automated pivotable cable-conduit management apparatus keeps electrically conductive wiring and flow tubing out of the path of the rotating robotic arm during welding.

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 solar power generation system includes a thermal energy storage vessel containing a thermal mass composition operable to store thermal energy, solar energy collection system, and power generation system. The collection system comprises a first closed flow loop including a solar collector which absorbs solar energy and heats a first working fluid. The heated first working fluid recirculates through a first closed flow loop through and heats the thermal mass composition. The generation system comprises a second closed flow loop including a turbine-generator. The second closed flow loop recirculates a second working fluid through the thermal mass composition to absorb thermal energy and heat the second working fluid which flows to the turbine and the generator produces electricity. The second working fluid may be water/steam or a compressible gas. The thermal mass composition comprises a mixture of a phase change material such as salt and a metallic material.

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 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 natural passively cooled ventilated cask includes a cavity which holds a canister containing heat and radiation emitting spent nuclear fuel assemblies or other high level wastes. Ambient ventilation or cooling air is drawn inwards beneath the cask and vertically upwards into a lower portion of the cavity through air inlet ducts formed integrally with a bottom canister support structure coupled to the cask. The air heated by the canister flows upwards in the cavity and returns to atmosphere through air outlet ducts in the cask lid. Air circulation is driven via natural convective thermo-siphon flow. Structural standoff members elevate the bottom of the cask above a concrete base pad forming an air inlet plenum beneath the canister support structure. The lateral sidewall surface of the cask has no penetrations for the air inlets, which eliminates any streaming path for radiation emanating from the spent nuclear fuel.