Abstract: Fuel assemblies of nuclear reactors that increase the efficiency of a filter for retention of foreign objects in the coolant while maintaining the hydraulic resistance of the fuel assembly at the same level. The nuclear reactor's fuel assembly comprises a head, a fuel elements bundle, spacer grids and the filter for retention of the foreign objects. The filter is installed in the bottom nozzle of a fuel assembly and is made in the form of rectilinear plates' groups, located in the cross section of the bottom nozzle.

Abstract: A modular water purification system for a nuclear power plant includes a plurality of modules that may be selectively connected together directly or through the use of intermediary adapters in a plurality of arrangements. The modules may include a pump module, a FOSAR module, a particulate filtration module, a cross-flow filtration module, a degasification module, and/or a demineralization module, among other possible modules. The modules may have common interfaces so that they can be interconnected (directly or through intermediary adapters) in a variety of configurations for different purposes within the context of the nuclear power plant (e.g., filtering pool water; collecting large objects via vacuuming). Various modules may have form factors and/or mounting structures that are similar enough to the fuel assemblies of the plant that (1) the plant's fuel assembly handling equipment can grab, move, and reposition the modules, and/or (2) the modules may be stored in the fuel pool's storage rack.

Abstract: Embodiments of a bottom nozzle of a nuclear fuel assembly provided with flow holes by utilizing a layered aircraft airfoil structure are provided. The bottom nozzle not only increases efficiency of filtering foreign substances by minimizing a size of the flow holes by constituting a shape of flow holes into cross stripes but also prevents coolant water flow velocity drop through prevention of coolant water pressure drop by constituting a lateral sectional shape of the grid frames constituting the cross stripes into an aircraft airfoil type.

Abstract: A system with function of bending and elongation is used for discharging foreign matters from nuclear reactor vessel. The system includes an operating rod which includes a suction pipe, a bendable rod section connected to the suction pipe, and an expandable rod section connected to the bendable rod section; and a drainage pipe. A suction opening is disposed at the suction pipe and an electric valve is disposed at a connection of the suction opening and the suction pipe. A filter mesh is disposed in the suction pipe; a suction pump is disposed in the suction pipe; a touch switch is disposed on the filter mesh. A water inlet of the suction pump is connected to the suction opening, a water outlet of the suction pump is connected to the outside space of the suction pipe though the drainage pipe, and the electric valve is controlled by the touch switch.

Abstract: A device for removing foreign objects from nuclear reactor vessel includes a suction pipe; a suction opening structure disposed at a lower end of the suction pipe, an electric valve disposed at a connection of the suction pipe and the suction opening structure, a filter mesh and a suction pump sequentially located in the suction pipe and above the electric valve. The suction opening structure has a suction opening thereon, a water inlet of the suction pump is communicated with the suction opening, and a water outlet of the suction pump is communicated with the outside space of the suction pipe though a drainage pipe. The device further includes a touch switch disposed on the filter mesh which is in operative connection with the electric valve. A foreign object impact force to the filter mesh triggers the touch switch to close which causes the electric valve to close.

Abstract: A bottom nozzle includes a skirt, support blocks, transverse blades and longitudinal blades. The skirt is a hollow structure and a bottom thereof is provided with corner legs which are protruded downwards, a cavity is defined in the hollow structure, the transverse blades are configured in the cavity, the longitudinal blades are configured in the cavity, the transverse blades and longitudinal blades are firmly connected with the skirt, projections of the transverse blades and the longitudinal blades in a level plane are intersectant to form interleaved grids, and the support blocks run through and are fixed on the transverse blades and the longitudinal blades. In such a way, the bottom nozzle forms a three-dimensional gridded water passage, thereby improving the filter capacity and generating small water pressure drop.

Abstract: A method and a corresponding device for the pressure relief of a nuclear power plant having an outlet for a relief flow. The relief flow is guided out of a containment into the atmosphere via a relief line provided with a filter system. The filter system has a filter chamber with a filter-chamber inlet and outlet and a sorbent filter arranged therebetween. The relief flow is guided in a high-pressure section of the relief line past the filter chamber, with the latter being heated, and the relief flow is expanded at the end of the high-pressure section and dried. In order for efficient retention of iodine-containing organic compounds, the relief flow is guided through a bed filter, guided in a superheating section past the high-pressure section of the relief line and in the process is heated, guided in this state directly thereafter through the filter chamber having the sorbent filter.

Abstract: A method and device is claimed for preventing reverse coolant flow in a BWR Power Reactor. The device comprises a screen that is free to move between a top plate and a bottom plate in a fuel assembly lower tie plate box. Flow holes are formed and aligned in the top plate and in the bottom plate, creating a path for reactor coolant. Disks at a bottom of the screen are aligned with the flow holes in the bottom plate, and are shaped and formed to cover flow holes in the bottom plate. When flow stagnates or reverses, the screen drops causing the disks to rest on the bottom plate blocking downward flow. Upstanding tabs at the top surface of the screen contact the top plate when normal coolant flow is in the upward direction, allowing flow through the flow holes in the top plate.

Abstract: A drainage system for engaging and removing accumulating drainage water with a sump pump liner, a sump pump disposed within the liner, and at least one contiguous void with an inner volume in fluidic communication with an inner volume of the liner. The void can comprise a low pressure void compartment disposed distal to the bottom of the liner, or the void can comprise a water harvesting arm with a proximal end retained by the main body of the liner and a body portion that projects from the main body. Liner-void apertures can be disposed in the bottom of the main body of the liner, and void-environment apertures can be disposed in a void bottom partition. The main body can have a rectangular cross section with a lateral water harvesting arm projecting from each sidewall.

Abstract: A method for purifying water in a spent fuel pool in a nuclear power plant, the method including passing the water at a linear flow velocity of 50 m/h or less through a purification apparatus. The apparatus includes an ion exchange resin layer and a metal-doped resin layer laid at a bed height of 2 cm or more on a surface layer of the ion exchange resin layer. The method includes contacting the water with the metal-doped resin layer to decompose a pro-oxidant contained in the water and subsequently contacting the water with the ion exchange resin to produce purified water.

Abstract: A method of follow-up decontamination operation for the polluted storage canister of a high activity nuclear waste storage facility, using needle and steel brushes driven by pneumatic tools for abrading the bottom and the inner wall of the storage canister to remove contaminants, a multi-level filter system for air filtration and removing pollutants in the storage canister, and a cover to be used in association with the pneumatic tools and the multi-level filtration system suitable to cap the storage canister, thus effectively block the exposure of contaminant of the storage canister to the external environment, achieving effective decontamination of the radioactive waste and reducing spreading to the environment.

Abstract: A particulate removal apparatus and method are used to capture and remove particulates from nuclear reactor core coolant during normal operation. Bottom nozzle, particulate removal apparatus and top nozzle structures form an assembly sized to be installed in place of a nuclear fuel assembly. The particulate removal achieved reduces the inventory of corrosion product deposits, foreign objects and other particulates in the reactor coolant system. This in turn reduces activation or deposition of particulates on fuel cladding, with a corresponding improvement in fuel reliability and reduction in ex-core radiation fields.

Abstract: An apparatus is provided to extract radioactive solid particles. An extracting nozzle is used to extract radioactive solid particles. Then, a separator is used to separate out the radioactive solid particles into a storing container. The radioactive solid particles are avoided from entering a suction pump. Not only the suction pump is not polluted, but also the secondary waste is not increased. By designing a falling inlet of a suction channel at a position having a specific height, the amount of the radioactive solid particles being extracted is under control. There is a radiation-protection device outside of the storing container to minimize radiation dose. The separator and the storing container can be rapidly detached by remote operation, so that operators are avoided from receiving over-dose radiation. Hence, the present invention improves the level of technology and automation for handling radioactive waste.

Abstract: A purification method for spent fuel pool water from nuclear power generation, the method comprising: passing the water at a linear flow velocity of 50 m/h or less through a purification apparatus for the water comprising an ion exchange resin layer and a metal-doped resin layer which is laid at a bed height of 2 cm or more on a surface layer of the ion exchange resin layer wherein the water to be treated is contacted with the metal-doped resin layer to decompose a pro-oxidant contained in the water; and subsequently contacting the water with the ion exchange resin.

Abstract: A system configured to passively filter radioactive materials from a flow may include one or more particulate removal devices; one or more water removal devices; and/or one or more radionuclide removal devices. At least one of the one or more particulate removal devices may mechanically remove particulates of the radioactive materials from the flow. At least one of the one or more water removal devices mechanically may remove water from the flow. At least one of the one or more radionuclide removal devices may remove radioactive aerosols, reactive radioactive gases, or radioactive aerosols and reactive radioactive gases from the flow using engineered filter media. A filter may include a body, including an inlet and an outlet. The body may be configured to store filter media, to contain pressure from gas explosions, and/or to allow the stored filter media to move toward the outlet when pressure at the inlet increases.

Abstract: The present invention relates to a passive filtration system for a fuel handling area having a spent fuel pool in a nuclear reactor. The passive filtration system reduces a discharge into the atmosphere of particulates, such as radioactive particulates, generated in a spent fuel pool boiling event. The passive filtration system includes a discharge path, a vent mechanism positioned between the fuel handling area and the discharge path. The vent mechanism is structured to release a steam and air mixture from the fuel handling area to the discharge path. The steam and air mixture includes the particulates. The passive filtration system further includes an air filtration unit located in the discharge path and this unit has at least one passive filter. The steam and air mixture is forced through the at least one passive filter due to a differential pressure generated in the fuel handling area.

Abstract: Illustrative embodiments provide a nuclear fission reactor, a vented nuclear fission fuel module, methods therefor and a vented nuclear fission fuel module system.

Abstract: A high capacity suction strainer for a nuclear reactor has a frame, a flow-through plenum, and a filter array. The flow-through plenum is mechanically mounted to the frame and has a plurality of inlets and an outlet. The filter array is also mechanically mounted to the frame and has a plurality of filter groupings in fluid communication with the inlet on the plenum.

Abstract: A method and an apparatus for performing a condensate demineralization treatment within a condensate demineralization apparatus of a nuclear power plant, which are capable of producing a high-purity treated water containing a low concentration of sulfate ions derived from the TOC eluted from a cation exchange resin. A condensate demineralization method for performing a demineralization treatment of a condensate from a nuclear power plant using an ion exchange resin, wherein the demineralization treatment of the condensate is performed by bringing the condensate into contact with an ion exchange resin bed that includes a mixed bed prepared by uniformly mixing a strongly acidic gel-type cation exchange resin and a strongly basic type 1 porous anion exchange resin having a cross-linking within a range from 1% to 4%.

Abstract: A filter is provided which includes channels for circulation of coolant fluid through the filter, at least one channel extending along a channel centerline and includes an upstream section, a downstream section and an intermediate section extending between the upstream section and the downstream section and being enlarged relative to the upstream section and the downstream section. The filter also includes at least one separating member defining inside the intermediate section of the at least one channel an annular passage whose axis is substantially coaxial to the channel centerline in the intermediate section.

Abstract: A filter including a plurality of flow ducts extending in a longitudinal direction and each delimited between one pair of walls is provided. The filter includes deflectors protruding into each duct alternately from the pair of walls with overlapping in the longitudinal direction to define a zigzag shaped flow channel and provided with at least one set of holes aligned in the longitudinal direction to define through the overlapping deflectors a passage for accommodating a lower end pin of a fuel rod.

Abstract: The invention is directed to a purifying device for sludge under water and a method for operating the same. The device includes a main fixing frame having an accommodating portion assess to the outside, a hollow liquid container in the accommodating portion, wherein the liquid container is provided with a liquid-flow hole and at least a backwash hole, multiple filters on the liquid container, and a pump connected to the liquid-flow hole at the liquid container through a liquid pipeline. The method includes steps: moving the liquid container having the filters to an area having a liquid to be filtered; leading the liquid to flow into the liquid container through the filters filtering out solid particles contained in the liquid; and leading a fluid to flow into the liquid container such that the filters can be backwashed accompanying with an external cleaning device if the filters are clogged.

Abstract: The geometric dimensions and shape of a device for removing solid particles from the cooling medium that is circulated in the primary circuit of a nuclear reactor, in particular a boiling water nuclear reactor, are such that the device can be inserted in lieu of a fuel element or fuel assembly into an empty fuel element or assembly position of the reactor core of the nuclear reactor.

Abstract: A nuclear plant has a containment shell and a pressure relief pipe connected thereto in which a blowing device and a Venturi washer placed in a container with a washing liquid are connected in series. Even the finest particles or aerosols carried by air are held in the Venturi washer with a very high degree of reliability and the release thereof in environment is excluded in a particularly reliable manner in the case of decompression even associated with seal failures. For this purpose, the size of the blowing device and the Venturi washer are selected in such a way that during the operation of the blowing device a flow rate of liquid in the Venturi washer flowing to the decompressing pipe is higher than 130 m/sec, preferably higher than 180 m/sec.

Abstract: In a debris trap that may be used in an Emergency Core Cooling System of a nuclear power plant, the filter media is arranged to define both filtration and bypass flowpaths that are in fluid communication with one another. At least initially, each of the filtration and bypass flowpaths are open, and the filtration and bypass flowpaths have relatively low and relatively high head loss, respectively. The debris trap is operative so that flow through the debris trap may passively, and typically gradually, transition from the filtration flowpaths to the bypass flowpath in response to the filter media collecting increasing amounts of debris. More specifically, initially substantially all of the flow may be through the filtration flowpaths, and thereafter the filtration flowpaths may become substantially obstructed so that substantially all of the flow is through the bypass flowpath.

Abstract: A lower nozzle for use in a nuclear fuel assembly provided. The lower nozzle is of the type having an axis and comprising a transverse lower tie plate for channelling the coolant through the lower tie plate and a tubular skirt extending axially from the periphery of the lower tie plate, the skirt delimiting an axial housing closed at one end by the lower tie plate and open at the opposite end, a debris filter configured for axial insertion in the housing and snap-fit springs for retaining the debris filter in the housing after insertion. The springs are configured to shift the debris filter axially towards the lower tie plate.

Abstract: A strainer wall structure includes curved sections, a method of manufacturing the same, and a filtering method using the strainer wall structure to provide a substantially larger effective filtering area in the same length and width, substantially reducing foreign substances covering a suction surface and flow resistance of the foreign substances, and reducing pressure drop at a cooling water pass corresponding thereto. The strainer wall structure includes an inlet side through which cooling water is introduced and an outlet side through which the filtered cooling water is discharged, includes a body having openings in directions of the inlet side and the outlet side, and a first filter plate inserted into the body and including curved sections formed by alternately bending a first punched plate having filtering holes in opposite directions and at a predetermined interval.

Abstract: A debris filter for a nuclear reactor installation is provided. The debris filter comprises a plurality of plates arranged side-by-side in a spaced relationship and delimiting between them flow passages extending through the debris filter from a lower inlet face to an upper outlet face of the debris filter, each passage having an intermediate section offset with respect to an inlet section and an outlet section. At least one of the plates is formed with debris catching features distributed along the plate and protruding into at least one passage delimited by the plate.

Abstract: A method for processing a coolant includes filtering a coolant using a first filtration system to generate a first filtered material, and filtering the filtered coolant using a second filtration system to generate a second filtered material. The second filtration system is different from the first filtration system. The first filtered material is transferred to a first waste treatment container and converted to a first waste product for permanent disposal, and the second waste product is transferred to a second waste treatment container and converted to a second waste product for permanent disposal.

Abstract: A radioactive debris trap to be installed in a steam generator for removing debris in the primary flow of a nuclear power plant's primary heat transport system. The debris trap includes an outer cylinder and a coaxial inner cylinder both having a top end and a bottom end. A top plate connects the top ends of the outer and inner cylinders. A bottom plate which encloses the trap is connected to the bottom end of the outer cylinder. There is a gap between the bottom end of the inner cylinder and the bottom plate through which primary flow enters a settling chamber located in an annular gap between the outer and inner cylinders. Several small holes are located at the top end of the outer cylinder through which liquid exits the debris trap. A means for fixedly connecting the debris trap to the steam generator is provided on the outer surface of the outer cylinder. Also included is a means for removing the radioactive debris trap from the steam generator without exposing personnel to excessive radiation.

Abstract: A debris exclusion and retention device traps and retains foreign material within the lower tie plate of the fuel assembly utilizing the existing flow paths within the lower tie plate, and without redirecting coolant flow. Flow through the inlet nozzle of the lower tie plate into an enlarged lower tie plate housing creates strong jet impingement against the center of the lower tie plate grid or debris filter, if present, which has a tendency to push debris to the periphery of the lower tie plate. Low flow zones around the periphery of the lower tie plate allow debris to fall back toward the inlet nozzle. The retention device traps and retains debris in these low flow zones without impacting existing flow patterns in the lower tie plate. Thus, the retention device has minimal or no impact on lower tie plate pressure drop.

Abstract: In a nuclear reactor core having fuel assemblies with upper and lower end fittings, a debris filter plate is attached to a lower end fitting having a skirt. The filter prevents debris from entering the fuel assembly, while the skirt prevents the trapped debris from sliding off the lower end fitting and continuing into the core. The lower end fitting is formed from a substantially square base and has flow channels to allow coolant to flow through it to the fuel assembly. The skirt is an extension of the metal of the lower end fitting that extends around the perimeter of the lower end fitting, spanning all four corners of the lower end fitting. In addition to capturing debris, the skirt also positions the filter, which may be manufactured from the same metal as the lower end fitting.

Abstract: A radioactive debris trap to be installed in a steam generator for removing debris in the primary flow of a nuclear power plant's primary heat transport system. The debris trap includes an outer cylinder and a coaxial inner cylinder both having a top end and a bottom end. A top plate connects the top ends of the outer and inner cylinders. A bottom plate which encloses the trap is connected to the bottom end of the outer cylinder. There is a gap between the bottom end of the inner cylinder and the bottom plate through which primary flow enters a settling chamber located in an annular gap between the outer and inner cylinders. Several small holes are located at the top end of the outer cylinder through which liquid exits the debris trap. A means for fixedly connecting the debris trap to the steam generator is provided on the outer surface of the outer cylinder. Also included is a means for removing the radioactive debris trap from the steam generator without exposing personnel to excessive radiation.

Abstract: Example embodiments are directed to upper tie plates for debris mitigation and fuel bundles that use the upper tie plates. Example embodiment tie plates may include a plurality of debris capture elements that overlap each other so as to create debris traps for particulate debris that would fall onto the fuel bundle. Example embodiment fuel bundles may use the upper tie plates for debris mitigation.

Abstract: The present application is related to a concentrated decontaminating reagent composition and related method useful for decontamination of nuclear reactors, or components thereof. The concentrated reagent composition is injected into the nuclear reactor, or component thereof, to form a dilute reagent that comprises from about 0.6 to about 3.0 g/L (2.1-10.3 mM) EDTA and from about 0.4 to about 2.2 g/L (2.1-11.5 mM) citric acid. The composition and method of this application can be used effectively in a regenerative process to decontaminate a nuclear reactor, or a component of thereof, with high efficiency without causing significant corrosion to the components of the cooling systems.

Abstract: A particulate removal apparatus and method are used to capture and remove particulates from nuclear reactor core coolant during normal operation. Bottom nozzle, particulate removal apparatus and top nozzle structures form an assembly sized to be installed in place of a nuclear fuel assembly. The particulate removal achieved reduces the inventory of corrosion product deposits, foreign objects and other particulates in the reactor coolant system. This in turn reduces activation or deposition of particulates on fuel cladding, with a corresponding improvement in fuel reliability and reduction in ex-core radiation fields.

Abstract: A strainer wall structure that removes foreign substances from a fluid suctioned into a pipe and a re-circulation pump that is part of an emergency core cooling system (ECCS). The strainer wall structure has an inlet side and an outlet side through which cooling water is introduced and discharged, respectively, and includes a body having an opening in a direction of the inlet side, closed side surfaces, and an outlet port disposed at one of the closed side surfaces. The strainer includes a punched plate filter screen inserted into the opening. A modular cassette apparatus including grooved first filter plates is inserted into the body, and second filter plates having second grooves is inserted into the first grooves.

Abstract: A radioactive debris trap to be installed in a steam generator for removing debris in the primary flow of a nuclear power plant's primary heat transport system. The debris trap includes an outer cylinder and a coaxial inner cylinder both having a top end and a bottom end. A top plate connects the top ends of the outer and inner cylinders. A bottom plate which encloses the trap is connected to the bottom end of the outer cylinder. There is a gap between the bottom end of the inner cylinder and the bottom plate through which primary flow enters a settling chamber located in an annular gap between the outer and inner cylinders. Several small holes are located at the top end of the outer cylinder through which liquid exits the debris trap. A means for fixedly connecting the debris trap to the steam generator is provided on the outer surface of the outer cylinder. Also included is a means for removing the radioactive debris trap from the steam generator without exposing personnel to excessive radiation.

Abstract: The present invention relates to a system and method for removing dissolved gas from makeup water in a water-cooled nuclear reactor. The present invention includes a storage tank for containing the makeup water that includes the dissolved gas, a membrane system positioned downstream of the storage tank to at least partially remove the dissolved gas from the makeup water; and a transport mechanism to transfer the makeup water from an outlet of the membrane system for use in the water-cooled nuclear reactor. The dissolved gas can include at least one of dissolved oxygen, dissolved nitrogen, dissolved argon and mixtures thereof.

Abstract: A method to confine a nuclear reactor fuel bundle assembly including: inserting a lower portion of the fuel bundle assembly into an open end of a lower fuel particle barrier; supporting the lower portion of the fuel bundle with the lower fuel particle barrier; grasping the lower portion of the fuel bundle assembly with the lower fuel particle barrier; lowering an upper fuel particle barrier over an upper tie plate of the fuel bundle assembly; moving at least a portion of a handle fixed to the upper tie plate through an open slot in the upper fuel particle barrier; closing the open slot with a closure device after the handle passes through the slot, and preventing fuel particles being released from the nuclear reactor fuel bundle assembly by the upper and lower fuel particle barriers.

Abstract: This invention relates to a nuclear plant having a reactor vessel and a fluid circuit including flow path defining means, defining a flow path for circulating a reactor coolant fluid from and to the reactor vessel. The nuclear plant includes a particle collection zone defined along at least part of the length of the flow path, and particle deflection means arranged in particle deflecting relationship with the flow path to deflect particles from a fluid stream in the flow path into or toward the particle collection zone.

Abstract: A filter is provided for cooling water conducting primary circuit of a nuclear power station. The power station contains a reactor container with a discharge opening for the cooling water that opens into the interior of the reactor container and being accessed when the power station is brought to a stop for an inspection shutdown. The filter contains a base carrier with an entrance, at least one filter cartridge held on the base carrier and is fluidically coupled to the entrance, and a fixing device that can be fixed to the discharge end such that the entrance couples fluidically to the discharge opening. In a method for filtering cooling water during the inspection shutdown a filter is fixed, by its fixing device, with its entrance in fluid connection with the discharge opening, the cooling water is circulated through the discharge opening, and the filter is removed from the discharge opening.

Abstract: A filtration separation method for waste resin containing highly radioactive uranium powder and device thereof is mainly used for the waste resin after water treatment process in a nuclear facility. The uranium powder contained in the waste resin is highly radioactive. Thus, prior to the treatment of the waste resin, it is necessary to filter and separate the highly radioactive uranium powder to reduce the radioactivity. It is to put the uranium powder containing waste resin into an underwater holding tank and withdraw the waste resin by an underwater pump into a uranium powder filtration box. Then the uranium powder filtration box is lifted by a hoist to move to an underwater ultrasonic cleaner. High-pressure water flushing is applied and followed by underwater ultrasonic cleaning. Then the cleaning water (containing precipitated uranium powder) from the ultrasonic cleaner is drained to uranium powder collection device.

Abstract: The present invention relates to a passive filtration system for a fuel handling area having a spent fuel pool in a nuclear reactor. The passive filtration system reduces a discharge into the atmosphere of particulates, such as radioactive particulates, generated in a spent fuel pool boiling event. The passive filtration system includes a discharge path, a vent mechanism positioned between the fuel handling area and the discharge path. The vent mechanism is structured to release a steam and air mixture from the fuel handling area to the discharge path. The steam and air mixture includes the particulates. The passive filtration system further includes an air filtration unit located in the discharge path and this unit has at least one passive filter. The steam and air mixture is forced through the at least one passive filter due to a differential pressure generated in the fuel handling area.

Abstract: A debris filter for reactor coolant includes a plurality of adjacent plates defining a plurality of channels therebetween, each of said channels being at an angle to the flow path of the coolant into the filter.

Abstract: A nuclear fuel assembly for a boiling water reactor is provided. The nuclear fuel assembly includes a base, a head and a bundle of full length fuel rods and partial length fuel rods. The bundle extends longitudinally between the base and the head, at least one partial length fuel rod having a lower end received in a housing provided in the base and delimited by a closed bottom larger than the lower end. The housing is further delimited by a peripheral wall surrounding the lower end and the partial length fuel rod rests freely on the bottom.

Abstract: An outer filter removal tool for a boiling water reactor control rod drive that uses a mechanical advantage obtained through the use of lead screw threads to pull the outer filter off of the control rod drive. Fingers on the tool are closed around the upper flange of the outer filter by sliding a collar over the outwardly biased fingers. A shaft extending through the tool is rotated which in turn extends a push plate against the control rod drive index tube causing the fingers to pull against the upper flange on the outer filter until the filter is freed from the control rod drive. The tool will hold the filter in place until affirmatively released for proper disposal.

Abstract: A debris exclusion and retention device traps and retains foreign material within the lower tie plate of the fuel assembly utilizing the existing flow paths within the lower tie plate, and without redirecting coolant flow. Flow through the inlet nozzle of the lower tie plate into an enlarged lower tie plate housing creates strong jet impingement against the center of the lower tie plate grid or debris filter, if present, which has a tendency to push debris to the periphery of the lower tie plate. Low flow zones around the periphery of the lower tie plate allow debris to fall back toward the inlet nozzle. The retention device traps and retains debris in these low flow zones without impacting existing flow patterns in the lower tie plate. Thus, the retention device has minimal or no impact on lower tie plate pressure drop.

Abstract: In a method of fast reduction of all iodine species, exclusively, including all volatile iodine species, into non-volatile iodide ions in an aqueous solution, a reducing agent and a co-agent with phase transfer catalyst—ion-exchanger property are simultaneously added to the aqueous solution and concurrently, thermal and radiolytic oxidation of iodide ions, otherwise yielding to revolatilzation, is suppressed producing an efficient retention of all iodide species in the aqueous solution.

Abstract: The reactor containment structure is provided with a reactor containment vessel, a reactor containment chamber installed inside the reactor containment vessel to contain a nuclear power reactor, a pool installed inside the reactor containment vessel so as to be below the reactor containment chamber adjacently and in which an emergency cooling liquid is stored, an opening part for allowing the emergency cooling liquid to flow from the reactor containment chamber into the pool, a sump installed below the pool, a debris filtering body installed at the sump to filter debris contained in the emergency cooling liquid, a pumping system which sucks the emergency cooling liquid from the sump and discharges the emergency cooling liquid into the reactor containment chamber, and a debris trapping part installed in the pool to trap the debris, wherein the debris trapping part intersects with a flow path of the emergency cooling liquid.