Abstract: Maintainability of a traversing in-core probe is improved without any hindrance to passage and the like in an access tunnel in which an indexing device of a TIP system is installed. An indexing device installation unit provided in the TIP system includes: a base on which an indexing device of a traversing in-core probe used in a nuclear reactor is mounted; a holding part holding the base in a suspended state in an access tunnel formed in a nuclear reactor containment vessel; and a lift mechanism moving up and down the base held by the holding part together with the indexing device.

Abstract: A power module assembly includes a reactor vessel containing a reactor core surrounded by a primary coolant. A containment vessel is adapted to be submerged in a containment cooling pool and to prohibit a release of the primary coolant outside of the containment vessel. A secondary cooling system is configured to remove heat generated by the reactor core. The heat is removed by circulating liquid from the containment cooling pool through the primary coolant.

Abstract: One embodiment of the present invention includes a process for production and recovery of no-carrier-added radioactive tin (NCA radiotin). An antimony target can be irradiated with a beam of accelerated particles forming NCA radiotin, followed by separation of the NCA radiotin from the irradiated target. The target is metallic Sb in a hermetically sealed shell. The shell can be graphite, molybdenum, or stainless steel. The irradiated target can be removed from the shell by chemical or mechanical means, and dissolved in an acidic solution. Sb can be removed from the dissolved irradiated target by extraction. NCA radiotin can be separated from the remaining Sb and other impurities using chromatography on silica gel sorbent. NCA tin-117m can be obtained from this process. NCA tin-117m can be used for labeling organic compounds and biological objects to be applied in medicine for imaging and therapy of various diseases.

Abstract: A computer-implemented system and method for managing operations in a nuclear power plant generates an electronic request for a permit to perform work in the plant, performs a risk assessment using a rules engine to determine a level of fire risk posed by the work, automatically determines one or more compensatory measures to provide protection against the level of fire risk posed by work, generates a risk score based the probabilistic assessment, and generates electronic authorization for the permit based on the risk score.

Abstract: A spacer grid for nuclear fuel rods includes a plurality of unit spacer grids stacked one on top of another. Each unit spacer grid includes a plurality of unit spacer grid straps disposed at regular intervals in a row, and a plurality of fixing grid straps connected to respective opposite ends of the unit spacer grid straps so as to fix the unit spacer grid straps. Each unit spacer grid strap has convexities alternating with each other on opposite sides thereof at regular intervals, and at least one of the convexities has a diameter greater than the others. The unit spacer grids are rotated in one direction by a 90 or 180 degree angle when being stacked.

Abstract: A fuel assembly for a nuclear reactor that employs dissimilar materials for the fuel assembly grid and the control rod guide thimbles. The guide thimbles are secured to the grid employing a through grid cell sleeve that is welded to the grid and spot weld rings that are secured over the sleeve and welded directly to the guide tube through windows in the sleeve.

Abstract: In a nuclear power plant, a corrosion-resistant oxide film on a surface of the metal component of a reactor structure is exposed to a high-temperature water, the corrosion-resistant oxide film containing an oxide having a property of a P-type semiconductor, and a catalytic substance having a property of an N-type semiconductor is deposited on the oxide film. The oxide film maintains the property of the P-type semiconductor.

Abstract: Example embodiments relate to a method and apparatus for reducing electrostatic deposition of charged particles on wetted surfaces that are exposed, periodically or substantially continuously, to high velocity fluid flow within a coolant flow path in a nuclear reactor. The method may include depositing a first or base dielectric layer and a second or outer dielectric layer on a conductive surface that forms a portion of a high velocity flow path to attain the apparatus. The first dielectric layer material is selected to provide improved adhesion and insulation to the conductive surface and the second dielectric layer material is selected to provide suitable adhesion to the first dielectric layer and improved corrosion and/or mechanical resistance in the anticipated operating environment.

Abstract: A natural-circulation type boiling water reactor includes a plurality of divided chimneys provided above a reactor core and a number of fuel assemblies are charged in the reactor core. The natural-circulation type boiling water reactor is provided with a pressure equalization structure arranged on rectangular-columnar lattice plates of the divided chimneys for equalizing pressures in divided chimney portions so as to equalize the pressures of the divided chimneys with the pressure equalization structure.

Abstract: An article made by applying a burnable poison onto the cladding of a nuclear fuel rod, which involves providing a nuclear fuel rod and at least one application device, rotating the nuclear fuel rod, optionally removing one or more oxides and/or surface deposits on the outer surface of the nuclear fuel rod by spraying an abrasive material onto the nuclear fuel rod via the application device while adjusting the position of the application device in relation to the nuclear fuel rod, and applying burnable poison particles onto the outer surface of the nuclear fuel rod by spraying the burnable poison onto the nuclear fuel rod via the application device while adjusting the position of the application device in relation to the nuclear fuel rod, where the burnable poison particles are applied at a velocity sufficient to cause adhesion to the outer surface of the cladding.

Abstract: The present invention relates to an irradiation device for material test using a gamma ray radiated from a spent nuclear fuel assembly and provides the irradiation device for material test using a gamma ray radiated from a spent nuclear fuel assembly wherein an irradiation device for material test to achieve a radiation effect evaluation is manufactured to be movable upward, downward and horizontally in order to study the hardening phenomenon of the frail materials to the radiation among the atomic power facilities using a gamma ray radiated from a spent nuclear fuel assembly, thereby it is possible to adjust a position of the spent nuclear fuel used for material test using a gamma ray radiated from a spent nuclear fuel and a test material, identify a distance between the spent nuclear fuel and the test material easily with a scale and evaluate the radiation effects on the materials used at facilities handling a spent nuclear fuel under the same situation as they are really exposed.

Abstract: A digital rod control system that employs separate power modules to energize the respective coils of a magnetic jack control rod drive rod drive system so that two, independently powered grippers can simultaneously support the control rod drive rod when it is not in motion to avoid dropped rods. The basic building block of the system is two or more selecting cabinets which receive multiplex power from at least one moving cabinet and are under the control of a single logic cabinet. Each of the cabinets include monitoring features to confirm the reliability of the system.

Abstract: A locking mechanism for securing hatches internal to a steam generator that is made up of only mechanical locking elements with fully captured moving parts. The mechanism employs a locking pin with redundant mechanisms to secure the pin in the closed position. The moving parts of the device can be attached directly to a removable hatch so that installation and repairs that may be required can be performed outside of the pressure vessel of the steam generator.

Abstract: A spacer grid for a nuclear fuel assembly for a light water reactor delimits a substantially regular array of cells housing nuclear fuel rods. The spacer grid further including supporting members which project into the cells from the peripheral belt of walls. The inner surface of at least one supporting member has before irradiation a concave shape in a plane transverse to the longitudinal direction. The inner surface of the contact part of the supporting member also has a convex shape in a longitudinal plane orientated radially with respect to the central axis of the corresponding cell before irradiation.

Abstract: In an underwater remote surface inspection method for a reactor constituting member, in order to improve the precision of an operation of inspecting a surface shape of the reactor constituting member, an underwater remote surface inspection apparatus includes a replica picking head, an ultrasonic vibrator, and a replica agent cartridge. The replica picking head is pressed against a surface of core internal structure as an inspection target. A replica agent is supplied from the replica agent cartridge into the replica agent supply region formed inside the replica picking head and contacting with the surface of the core internal structure. After the operation of supplying the replica agent ends, an ultrasonic wave is transmitted from an ultrasonic vibrator to the replica agent inside the replica agent supply region. Accordingly, gas bubbles or liquid bubbles existing inside the replica agent supply region rise up so as to be discharged to the outside of the replica picking head through an air extracting hole.

Abstract: An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accommodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through which the dowel pins pass.

Abstract: Systems and methods for storing radioactive materials that afford adequate ventilation of the cavity in which the radioactive materials are stored. In one aspect, the invention is a method of storing radioactive materials comprising: a) positioning a system comprising a shell forming a cavity and at least one inlet ventilation duct extending from an inlet to an outlet at a bottom portion of the cavity in a below grade hole so that the inlet of the inlet ventilation duct is above grade and the outlet of the inlet ventilation duct into the cavity is below grade; b) introducing engineered till into the hole to circumferentially surround the shell; c) lowering a canister containing radioactive materials into the cavity; and d) subsequent to the canister being lowered into the cavity, placing a lid on the shell.

Abstract: An object of the present invention is to provide an inspection apparatus for inspecting weld zones in a reactor pressure vessel, the inspection apparatus comprising: an ultrasonic probe 6 for emitting an ultrasonic wave; a probe holding unit 60 for holding the ultrasonic probe 6 such that a ultrasonic wave transmitting surface of the ultrasonic probe 6 is kept in direct contact with or at a constant distance from the outer surface of the reactor pressure vessel 1; a pressing unit 50 for pressing the probe holding unit 60 parallel to a central axis of a control rod drive housing 8 against the reactor pressure vessel; and a rotator 40 for rotating the probe holding unit 60 and the pressing unit 50 about the central axis of the control rod drive housing 8.

Abstract: To provide a rod block monitor in which irrespective of the selection or non-selection of a control rod, such a process is repeatedly executed that gain adjustment is performed at fixed intervals at all times to match a local area average value of signals of neutron detectors surrounding the control rod with a nuclear reactor average power and a block level appropriate to the local area average value of the neutron detector signals after the gain adjustment is set.

Abstract: A fuel compact formed by integrally molding coated fuel particles by a press into a cylindrical body and comprising a chamfer having plane or curved surface at its corner to thereby prevent the coated fuel particles from being damaged due to stress on press molding whereby the strength thereof is improved against mechanical contact with a fuel sleeve and a graphite block.