Abstract: Sodium-cesium trap systems and methods for the simultaneous removal of both sodium (Na) and cesium (Cs) in gas are provided. The trap system includes a contacting vessel having an inlet and an outlet with carrier gas channeled therethrough. A heating system maintains a temperature gradient across the contacting vessel between a first temperature at the inlet and a second temperature at the outlet such that sodium and cesium contained within the carrier gas are condensed into liquid and the carrier gas exiting the vessel is substantially free of sodium and cesium.

Abstract: Systems are provided for inspection and tooling submerged in nuclear reactors. Systems mount at the reactor edge, such as on a steam dam, to be independently operable from a refueling bridge or refueling operations. A moveable steam dam clamp may hold a position apparatus at the edge. The positioning apparatus includes a rotatable shoulder and arms move a tool, reactor component, and/or inspection device like a camera or VARD to desired and highly-determinable reactor positions. A float may counter shear and rotation on the shoulder from the arms. Motors at the shoulder with internal transmissions may rotate the shoulder and arms, or manual rotation may be used. The arms may also overlap vertically for installation and removal. Power, controls, and/or data may be provided underwater through an umbilical connection to operators.

Abstract: An apparatus for processing a plurality of semiconductor wafers, the apparatus including a spallation chamber, a neutron producing material mounted in the spallation chamber, a neutron moderator, and an irradiation chamber coupled to the spallation chamber, wherein the neutron moderator is disposed between the spallation chamber and the irradiation chamber, wherein the irradiation chamber is configured to accommodate the plurality of semiconductor wafers, wherein each of the plurality of semiconductor wafers has a first surface and a second surface opposite the first surface, wherein the plurality of semiconductor wafers are positioned so that a first surface of one semiconductor wafer faces a second surface of another semiconductor wafer.

Abstract: An apparatus for generating medical isotopes provides an annular fissile solution vessel surrounding a neutron generator. The annular fissile solution vessel provides for good capture of the emitted neutrons and a geometry that provides enhanced stability in an aqueous reactor. A neutron multiplier and/or a neutron moderator may be used to improve the efficiency and control the criticality of the reaction in the annular fissile solution vessel.

Abstract: According to an embodiment, a core catcher has: a main body including: a distributor arranged on a part of a base mat in the lower dry well, a basin arranged on the distributor, cooling channels arranged on a lower surface of the basin connected to the distributor and extending in radial directions, and a riser connected to the cooling channels and extending upward; a lid connected to an upper end of the riser and covering the main body; a cooling water injection pipe open, at one end, to the suppression pool, connected at another end to the distributor; and chimney pipes connected, at one end, to the riser, another end being located above the upper end of the riser and submerged and open in the pool water.

Abstract: The invention provides a method for generating medical isotopes, the method comprising contacting a primary radiation beam with a converter for a time sufficient to produce a secondary beam of gamma particles, and contacting the beam of gamma particles to a target, where the cross section dimension of the beam of gamma particles is similar to the cross section dimension of the target. Both the converter and target are small in diameter and very closely spaced. Also provided is a system for producing medical isotopes, the device comprising a housing having a first upstream end and a second downstream end, a radiotransparent channel (collimator) with a first upstream end and a downstream end, wherein the upstream end is adapted to receive a radiation beam, a target positioned downstream of the downstream end of the channel and coaxially aligned with the channel, wherein the target has a cross section that is similar to the cross section of the channel.

Abstract: A nuclear reactor is positioned on a barge which floats on the water of a water tank. The water tank includes a bottom wall, first and second end walls and first and second side walls. The bottom wall includes a lower layer of concrete, an intermediate layer of water impervious material positioned on the lower layer of concrete, and an upper layer of concrete positioned on the intermediate layer of water impervious material. Each of the first and second end walls and the first and second side walls includes an outer layer of concrete, an intermediate layer of water impervious material positioned at the inner side of the outer layer of concrete, and an inner layer of concrete material positioned at the inner side of the intermediate layer of water impervious material.

Abstract: A nuclear reactor comprises a nuclear reactor core disposed in a pressure vessel. An isolation valve protects a penetration through the pressure vessel. The isolation valve comprises: a mounting flange connecting with a mating flange of the pressure vessel; a valve seat formed into the mounting flange; and a valve member movable between an open position and a closed position sealing against the valve seat. The valve member is disposed inside the mounting flange or inside the mating flange of the pressure vessel. A biasing member operatively connects to the valve member to bias the valve member towards the open position. The bias keeps the valve member in the open position except when a differential fluid pressure across the isolation valve and directed outward from the pressure vessel exceeds a threshold pressure.

Abstract: The invention relates to a nuclear fuel cladding comprising: i) a substrate containing a zirconium-based inner layer, optionally coated with at least one intermediate layer formed by at least one intermediate material selected from among tantalum, molybdenum, tungsten, niobium, vanadium, hafnium or the alloys thereof; and ii) at least one protective outer layer placed on the substrate and formed by a protective material selected from either chromium or an alloy of chromium. The nuclear fuel cladding produced using the method of the invention has improved resistance to oxidation/hydriding. The invention also relates to the method for the production of the nuclear fuel cladding by ion etching of the surface of the substrate and deposition of the outer layer on the substrate with a high power impulse magnetron sputtering method (HiPIMS), as well as to the use thereof to protect against oxidation and/or hydriding.

Abstract: A method and system detects failures in nuclear fuel assemblies (600). A water treatment device degasses/removes fission gases from water used in the canister (500) of a vacuum sipping device (30). A sipping procedure then detects a failure in a fuel assembly in the canister. The degassing improves a signal-to-noise ratio of the detector used during the sipping process, and improves the failure detection sensitivity of the system. Additionally and/or alternatively, gas may be recirculated through the canister water before the vacuum is applied so that fission gas concentration in the recirculating gas reaches a baseline equilibrium with the canister water. The vacuum is thereafter applied and the sipping procedure proceeds such that an increase in detected radioactivity over the baseline equilibrium indicates a leak in the fuel assembly.

Abstract: A nuclear power plant comprising a primary coolant circuit, a steam-water circuit separated from the primary coolant circuit and a steam generator connected to the primary coolant circuit and the steam-water circuit to transfer heat from the primary coolant circuit into the steam-water circuit has at least one dosing point in the steam-water circuit to inject a reducing agent into the steam-water circuit, wherein the reducing agent is an organic compound consisting of carbon, hydrogen and oxygen. Furthermore, a method for operating said nuclear power plant and the use of the method for downtime preservation of the secondary side of a steam generator of a nuclear power plant are provided.

Abstract: This disclosure relates to reactor control, and more particularly to a control rod drive mechanism and a reactor control system. The control rod drive mechanism includes a lifting-lowering assembly, a mounting assembly and a release assembly. The mounting assembly is configured to mount a control rod. The lifting-lowering assembly includes a fixing component, a scissor-type lifting-lowering mechanism and a lifting-lowering component. An end of the scissor-type lifting-lowering mechanism is connected to the fixing component, and the other end is connected to the lifting-lowering component. The scissor-type lifting-lowering mechanism is configured to drive the lifting-lowering component to move close to or away from the fixing component. The release assembly is movably arranged on the lifting-lowering component, and is detachably connected to the mounting assembly. The release assembly is configured to move relative to the lifting-lowering component when power is off to release the mounting assembly.

Abstract: The present invention discloses a compact integrated deuterium-deuterium (D-D) neutron generator. A hemispherical metal head is disposed inside a cylindrical ceramic shell of the generator and is provided therein with an ion source and an ion source power supply. An inner ceramic insulated cylinder and an outer ceramic insulated cylinder are disposed between a metal plate of the metal head and a baseplate of the generator, and an isolated power supply system and a high-voltage power supply are disposed between the inner ceramic insulated cylinder and the outer ceramic insulated cylinder. A rear end of an extraction accelerating electrode disposed inside the inner ceramic insulated cylinder protrudes from the generator and is then connected to a target holder disposed outside the baseplate. A target is disposed inside the target holder, the target is at ground potential, and a cooling water interface is disposed on the target holder.

Abstract: Disclosed is a gas targeting system including a body, which has a frustoconical cavity; a cooling circuit including at least one channel which surrounds at least one portion of the cavity; a window, positioned facing an inlet of the cavity in order to close the cavity, including a fine sheet that is permeable to at least a portion of a beam of particles emitted by a particle accelerator and a support grid configured to support pressure differences between and inside of the cavity and an outside of the targeting system, with the fine sheet positioned between the support grid and the cavity; and a support flange which holds the window and is hermetically secured on the body, and which includes a mechanical attachment interface at the outlet of a particle accelerator.

Abstract: A printed circuit heat exchanger for use in a reactor includes a core formed from a stack of plates diffusion bonded together. The core has: a top face, a bottom face disposed opposite the top face, a first side face extending between the top face and the bottom face, and a second side face disposed opposite the first side face. The printed circuit heat exchanger includes: a plurality of primary channels defined in the core, each of the primary channels extending from a primary inlet defined in the first side face to a primary outlet defined in the second side face; and a plurality of secondary channels defined in the core, each of the secondary channels extending among at least some of the primary channels from a secondary inlet defined in the top face to a secondary outlet defined in the top face.

Abstract: A pressurized water reactor (PWR) comprises a pressure vessel containing primary coolant water. A nuclear reactor core is disposed in the pressure vessel and includes a plurality of fuel assemblies. Each fuel assembly includes a plurality of fuel rods containing a fissile material. A control system includes a plurality of control rod assemblies (CRA's). Each CRA is guided by a corresponding CRA guide structure. A support element is disposed above the CRA guide structures and supports the CRA guide structures. The pressure vessel may be cylindrical, and the support element may comprise a support plate having a circular periphery supported by the cylindrical pressure vessel. The CRA guide structures suitably hang downward from the support plate. The lower end of each CRA guide structure may include alignment features that engage corresponding alignment features of the upper end of the corresponding fuel assembly.

Abstract: A method and apparatus for extending the period a nuclear steam supply system spent fuel pool can be safely passively cooled by storing the spent fuel offloaded from the reactor, in the containment for one reactor operating cycle. During a refueling the spent fuel that is not to be returned to the reactor and the spent fuel that will be returned to the reactor are stored separately in shielded locations within the containment. After one operating cycle, the spent fuel stored within the containment that was not returned to the reactor just prior to the last operating cycle, is offloaded to the spent fuel pool and replaced by the newly offloaded spent fuel that is being retired.

Abstract: A control rod operation generates a rod insertion block signal during operation of a reactor. Four neutron detector assemblies including a plurality of LPRMs arranged in an axial direction of a core are arranged adjacent to a plurality of insertion selection control rods, respectively, which are simultaneously inserted into the core. Neutron flux ratio calculation units are arranged in each of the neutron detector assemblies, and ratios (neutron flux ratios BA/AA, CA/AA, and DA/AA) of an average LPRM signal of the respective LPRMs at positions B, C, and D to an average LPRM signal of the respective LPRMs at a position A which is closest to the control rod insertion end of the core are calculated. When the largest neutron flux ratio out of the neutron flux ratios exceeds a set neutron flux ratio, a rod insertion block signal which is generated by a local range rod insertion monitor is output.

Abstract: A method of using a pipe cap assembly for a normally-sealed system includes attaching the base portion of a pipe cap to a pipe of a normally sealed system. A transition cap having internal threads is releasably coupled to an externally-threaded cylindrical connector portion of the pipe cap for sealing the same during normal operation. When access to the normally sealed system is required, the transition cap is unthreaded from the pipe cap, and a transition fitting is installed instead. A drain hose, vent hose, or the like, may be coupled to an access port of the transition fitting and fastened thereto for passing fluids to or from the normally sealed system. Alternatively, a test instrument may be coupled to the access port. Thereafter, the transition fitting is removed, and the transition cap is re-installed.

Abstract: A methodology is disclosed for compaction of a ceramic matrix of certain nuclear fuels incorporating neutron poisons, whereby those poisons aid in reactor control while aiding in fuel fabrication. Neutronic poisons are rare-earth oxides that readily form eutectics suppressing fuel fabrication temperature, of particular importance to the fully ceramic microencapsulated fuel form and fuel forms with volatile species.