Abstract: A debris trap catches debris falling through a fuel bundle orifice in a nuclear reactor. The debris trap includes a shaft and a debris capture tray attached to an end of the shaft. The debris capture tray includes a tray cavity sized larger than the fuel bundle orifice.

Abstract: An adsorbing substance made of a material having an acid center in its molecular frame is installed in a passage for steam generated in a reactor pressure vessel 1. The adsorbing substance adsorbs and holds N-16 compound for decay. Therefore, the amount of N-16 entering into a turbine system is decreased and dose in the turbine system can be reduced.

Abstract: A filter medium for strainers used in the emergency sump of a nuclear power plant ECCS. The filter medium is employed with double wall, concentric tube type strainer modules. The filter medium is preferably constructed of a woven or knitted stainless steel wire material and is shaped in a cylinder so that it can be inserted between two concentric strainer walls, concentric tube type strainer in such a manner that water that passes through the strainer must pass through and be filtered by the filter medium before the water can be pumped to the reactor core. The filter medium is inserted through the bottom of the strainer module and is held in place by an x-shaped retainer. The filter creates varied approach velocity of the fluid and results in non-uniform fibrous debris accumulation on the strainer, insuring acceptable strainer debris hydraulic head loss.

Abstract: A filter including a plurality of flow ducts extending in a longitudinal direction and each delimited between one pair of walls. According to one aspect of the invention, 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: A filter medium for strainers used in the emergency sump of a nuclear power plant ECCS. The filter medium is employed with double wall, concentric tube type strainer modules. The filter medium is preferably constructed of a woven or knitted stainless steel wire material and is shaped in a cylinder so that it can be inserted between two concentric strainer walls, concentric tube type strainer in such a manner that water that passes through the strainer must pass through and be filtered by the filter medium before the water can be pumped to the reactor core. The filter medium is inserted through the bottom of the strainer module and is held in place by an x-shaped retainer. The filter creates varied approach velocity of the fluid and results in non-uniform fibrous debris accumulation on the strainer, insuring acceptable strainer debris hydraulic head loss.

Abstract: Systems and methods for servicing a fuel assembly in a light water reactor include those for controlling flow through a fuel assembly to maintain debris in the fuel assembly during removal and transportation of the fuel assembly, those for discharging debris from the fuel assembly, and those for isolating and sampling the water chemistry of a fuel assembly. An exemplary system includes a closure device configured to seal a mast to a fuel assembly to surround the upper opening of the fuel assembly and provide a flow control channel between a void in the mast and a lower opening in a lower tie plate.

Abstract: A debris trap catches debris falling through a fuel bundle orifice in a nuclear reactor. The debris trap includes a shaft and a debris capture tray attached to an end of the shaft. The debris capture tray includes a tray cavity sized larger than the fuel bundle orifice.

Abstract: Disclosed is an apparatus and method whereby small particle nano materials may be contained in a highly functional package for fluid separation and/or purification applications. The package consists of an aerogel material which uniformly surrounds the nano-particles. The aerogel may be composed of carbon, silicon, or silicon oxide or other suitable materials. The morphological features of the aerogel may be tailored specifically towards fine particle and ultrafine particle containment while maintaining uniform fluid flow in separation and purification processes. The aerogel may be bonded to a suitable rigid housing by chemical or mechanical means.

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 may also include 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 debris filter bottom nozzle for a pressurized water nuclear reactor fuel assembly that employs a corrugated screen in combination with flow through holes in an adapter plate to filter out potentially damaging debris. The area between the screen and the adapter plate defines a plenum that forms a collection point for the debris and coolant access is provided to the plenum through openings in the screen and sidewalls of the nozzle.

Abstract: A nuclear fuel assembly bottom nozzle, of the type including a perforated plate to allow water to pass through it, the nozzle having lateral faces, and at least one anti-debris element positioned on a lateral face to block out debris likely to infiltrate between the bottom nozzle and another adjacent bottom nozzle, characterized in that, in the free state, the or each anti-debris element permanently projects from the lateral face on which it is positioned, the or each anti-debris element being elastically deformable so as to retract towards the lateral face in the event of a force being exerted on the anti-debris element towards the lateral face.

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 features 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: A strainer for an emergency core cooling system (ECCS) in a nuclear power plant comprises a perforated strainer element that is immersed in a reservoir of cooling water, which is drawn through the strainer element into the emergency core cooling system. The side of the strainer element in contact with the cooling water has a contoured configuration for disrupting the formation of a flat bed of fibrous material that can trap small particulate material intended to pass through the strainer element. Incorporating this strainer element into an ECCS strainer enables the strainer to be made more compact, because the debris bed need not be spread over an unduly large area to prevent excessive head loss from the debris load in the event of a reactor loss of coolant accident. The strainer also incorporates a modular construction that uses individual strainer disc modules. Each disc module includes a perforated first disc part having a central opening and a perforated second disc part also having a central opening.

Abstract: A protective screen for the screening off of a suction space and a suction duct connected to it in a cooling system, include at least one screen wall element which has a suction side and an outflow side. The screen wall element is built up from a plurality of modular rectangular cassette units, which respectively contain a plurality of suction pockets open towards the suction side, with the screen pockets being surrounded by outflow gaps which are open towards the outflow side.

Abstract: The invention refers to a device and a method for handling a fuel assembly (3), which comprises a number of fuel rods extending between a lower part and an upper part of the fuel assembly, a debris filter located in the lower part of the fuel assembly and a casing surrounding the fuel rods. The device comprises a lifting device (15) for engaging, during a lifting operation, a fuel assembly located in a reactor vessel (1) and lifting the fuel assembly upwards and out from the reactor vessel. A conduit member is connected to the upper part of the fuel assembly. A pump (32) creates a flow of water through the conduit member and the fuel assembly during the lifting operation. The flow has such a size that possible debris particles contained in and/or immediately beneath the debris filter at least are retained in and/or immediately beneath the debris filter during the iifting operation.

Abstract: A debris trap catches debris falling through a fuel bundle orifice in a nuclear reactor. The debris trap includes a shaft and a debris capture tray attached to an end of the shaft. The debris capture tray includes a tray cavity sized larger than the fuel bundle orifice.

Abstract: Environmentally protective Method of treating an aqueous radioactive fluid (AF) in a nuclear reactor cycle or radwaste system to selectively capture or remove radioactive isotopes in a reduced quantitative package to minimize radwaste generated and revitalize neutron absorption capacity of nuclear reactor coolant by separately carrying away boron constituents, when B10 is later added.

Abstract: By using a boric acid-resistant anion exchange resin as the anion exchange resin used in a demineralizer that purifies the primary cooling water in a pressurized-water reactor power plant, even when a boric acid-containing primary cooling water is brought into contact with the anion exchange resin disposed in the demineralizer, the generation of breaking or cracking in the anion exchange resin can be prevented.

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 method of suppressing deposition of radionuclides on components of a nuclear power plant comprises forming a ferrite film by contacting a first chemical including iron (II) ions, a second chemical for oxidizing the iron (II) ions to iron (III) ions, and a third chemical for adjusting the pH of a processing solution containing a mixture of the first and second chemicals to be 5.5 to 9.0 with the metal member surface in a time period from a finishing stage in decontamination step of removing contaminants formed on the surface of metal member composing the nuclear power plant, and suppressing deposition of radionuclides on the metal member by the ferrite film.

Abstract: In a fuel assembly for a nuclear reactor, a plurality of nuclear fuel rods and at least one fuel rod spacer assembly supporting the fuel rods in an organized array. The fuel rod spacer assembly includes a guide at a leading edge of the fuel rod spacer assembly. The guide is angled towards the fuel rod for directing debris to open passages in the fuel rod spacer assembly.

Abstract: A method to prevent debris falling into a nuclear reactor fuel assembly including a bundle of fuel rods mounted below an upper tie plate and housed in a channel including: inserting a debris shield in the upper tie plate; maintaining the shield in the upper tie plate and above the fuel rods, while the fuel assembly is in an operating nuclear reactor core; flowing coolant through the bundle and the debris shield during operation of the nuclear reactor core, and capturing or deflecting debris falling in the fuel assembly with the debris shield.

Abstract: A method to capture, retain and remove debris falling into a nuclear reactor fuel bundle assembly including a bundle of fuel rods mounted below an upper tie plate and housed in a hollow metal channel, the method includes: inserting a debris shield in the upper tie plate; maintaining the shield in the upper tie plate and above the fuel rods, and water rods, while the fuel bundle assembly is in an operating nuclear reactor core; capturing debris falling in the fuel assembly on the debris shield; after capturing the debris, removing the fuel bundle assembly with the inserted debris shield from the nuclear reactor core to a maintenance/fuel inspection pool and thereafter removing the debris shield from the upper tie plate, cleaning and then reinserting the cleaned debris shield back into the upper tie plate, and moving the fuel bundle assembly from the maintenance/fuel inspection pool back into the nuclear reactor core.

Abstract: A nuclear reactor fuel assembly including: an upper tie plate having apertures to receive and support fuel rods of a fuel bundle; the fuel bundle includes an array of the fuel rods mounted and housed in the walls of a channel, and a load bearing or non-load bearing debris shield may be mounted in the upper tie plate, wherein the debris shield is porous to prevent the passage of debris. The debris shield is mounted in the frame of the upper tie plate. The debris shield can be either a removable unit, or it can be attached as a permanent integrated structure within the upper tie plate. The upper tie plate frame is also porous, e.g., has small vertical openings to allow fluid to pass through the frame and block passage of debris. The openings in the frame increase the effective flow area of passages through the upper tie plate and thereby compensate or offset any flow restrictions due to the debris shield.

Abstract: A method of suppressing deposition of radionuclides on components of a nuclear power plant comprises forming a ferrite film by contacting a first chemical including iron (II) ions, a second chemical for oxidizing the iron (II) ions to iron (III) ions, and a third chemical for adjusting the pH of a processing solution containing a mixture of the first and second chemicals to be 5.5 to 9.0 with the metal member surface in a time period from a finishing stage in decontamination step of removing contaminants formed on the surface of metal member composing the nuclear power plant, and suppressing deposition of radionuclides on the metal member by the ferrite film.

Abstract: A fuel inlet mechanism to introduce a coolant into a fuel assembly configured to be charged in a light water nuclear reactor, includes, a filter catching a foreign substance included in the coolant on an upstream side of the fuel assembly, the filter having a plurality of through holes to pass the coolant, and the through holes having an inlet portion, an outlet portion and at least one bent portion to a degree by which the outlet portion cannot be seen through from the inlet portion by a straight line.

Abstract: A strainer wall (1) to screen off a suction space (3) and a suction duct (5) connected to it in an emergency cooling system of a nuclear power plant includes at least one strainer wall element (2) which has an inlet side (12) and an outflow side (13), wherein the inlet side is essentially oriented perpendicular. The strainer wall element (2) is built up from a plurality of modular cassette units (11), which respectively contain a plurality of screen elements (17.1?–17.nm) open towards the inlet side (12) and connected to the outflow side (13).

Abstract: The invention refers to a filter (1) for separating particle from cooling water in a nuclear plant, and a fuel assembly with such a filter. The filter has an inlet end (2) and an outlet end (3) and permits through-flow of the cooling water in a main flow direction (x). The filter includes a number of sheets (4) extending in the flow direction from the inlet end to the outlet end. The sheets are arranged beside each other and form passages for the cooling water. The sheets include a first portion (4?) extending from the inlet end (2), a second portion (4?) extending from the outlet end (3), and a third portion (4??) extending between the first portion (4?) and the second portion (4?). The sheets (4) have along the first portion continuous wave-shape extending in a direction (y) transversally to the flow direction (x) and along the third portion a continuous wave-shape extending in the flow direction (x).

Abstract: Migration of radioactive materials from a pressure vessel to a steam system in a nuclear power plant is suppressed by using a dryer (3) provided with corrugated plates (22) having surfaces coated with an inorganic ion-exchange material stable under a condition in which high-temperature water exist, such as TiO2.

Abstract: The invention relates to a guide tube especially for an instrumentation lance extending into a reactor pressure vessel. The guide tube includes a lower tube section and an upper tube section that extends into the interior of the reactor pressure vessel. In order to prevent radioactively contaminated particles from reaching the lower tube section disposed outside the reactor pressure vessel from forming a source of radiation, a separator is arranged in the upper tube section. The separator has a separation chamber in which the particles are deposited and are removed from the water.

Abstract: In a chemical decontamination apparatus, a catalyst decomposition column in an upstream side of an ion exchange resin column and a hydrogen peroxide injection apparatus in a further upstream side, reduce the amount of waste products caused by a chemical decontaminating agent where a mixed decontaminating agent for a composition trapped in a cation resin column and for a composition trapped in an anion exchange resin are used for the chemical decontaminating agent, selectively decompose the composition trapped in the cation resin column in an inlet side of a cleaning apparatus when radioactive nuclides in the decontaminating agent are cleansed using the cation resin column during decontamination, and decompose both compositions after completion of the decontamination. The chemical decontamination thus selectively decomposes the chemical decontaminating agent, which is a component of the load to the cation resin column.

Abstract: A filter for separating particles from cooling water in a nuclear plant of light water model. The filter has an inlet end (2) and an outlet end (3) and allow flowing through of the cooling water in a flow direction z from the inlet end to the outlet end. The filter comprises a plurality of channels (5) extending mainly in the flow from the inlet end to the outlet end. Each of the channels comprise a first (6) channel section provided closer to the inlet end, a second (8) channel section arranged closer to the outlet end, and an intermediate section (7) provided between the first and the second channel section. The intermediate section (7) has an extension d2 in a direction x transversely to the flow direction, which is essentially larger than the extension d1, d3 of the first and the second channel section. The filter further comprises a separating member (9) arranged in the intermediate section.

Abstract: A fuel assembly lower tie-plate with better performance in capturing linearly elongated foreign substances. The lower tie-plate has a screening plate positioned below the network section in the lower tie-plate cavity. The screening plate is arranged substantially horizontally so that the lower tie-plate cavity is divided into upper and lower parts by the screening plate. Tubular filters are attached to the screening plate so that the tubular filters have openings below and above the screening plate. Top ends of the tubular filters are closed, and the openings above the screening plate are formed in side walls of the tubular filters. The lower tie-plate may be assembled by combining the screening plate, the network section and the nozzle section together, after the tubular filters have been attached to the screening plate.

Abstract: In a demineralization apparatus, a mixed bed of a gel type cation exchange resin having a moisture holding capacity of 41% or less or a degree of crosslinkage of 12% or greater is employed along with a porous type anion exchange resin. As a result, oxidation degradation of the cation exchange resin due to hydrogen peroxide can be inhibited and the performance of the ion exchange resins and of the condensate water demineralizer can be stabilized and maintained for a long period of time.

Abstract: A nuclear fuel assembly includes a fuel bundle resting on a lower tie plate. The lower tie plate includes a grid having raised bosses disposed in a rectilinear array for receiving the end plugs of the fuel rods and webs interconnecting the bosses. Between the raised bosses and the end plugs, there is disposed a filter plate having holes registering with the holes through the bosses for receiving the end plugs and apertures providing an approximate 40% open area through the filter plate. The webs of the tie plate grid are recessed from the upper edges of the bosses, facilitating flow through the apertures of the filter plate.

Abstract: A nuclear fuel assembly includes a fuel bundle resting on a lower tie plate. The lower tie plate includes a grid having raised bosses disposed in a rectilinear array for receiving the end plugs of the fuel rods and webs interconnecting the bosses. Between the raised bosses and the end plugs, there is disposed a filter plate having holes registering with the holes through the bosses for receiving the end plugs and apertures providing an approximate 40% open area through the filter plate. The webs of the tie plate grid are recessed from the upper edges of the bosses, facilitating flow through the apertures of the filter plate.

Abstract: In a demineralization apparatus, a mixed bed of a gel type cation exchange resin having a moisture holding capacity of 41% or less or a degree of crosslinkage of 12% or greater is employed along with a porous type anion exchange resin. As a result, oxidation degradation of the cation exchange resin due to hydrogen peroxide can be inhibited and the performance of the ion exchange resins and of the condensate water demineralizer can be stabilized and maintained for a long period of time.

Abstract: A reduced pressure drop debris filter bottom nozzle for use in a fuel assembly of a nuclear reactor includes a plate member formed with a plurality of first flow holes and a plurality of second flow holes. The first flow holes are oblong in cross section and may be of an oval configuration. The first flow holes each have in cross section a major axis and a minor axis, the major axis being longer than the minor axis. The second flow holes are circular in cross section and may have a diameter substantially equal to the minor axis of the first flow holes. The bottom nozzle also features support ligaments that extend between the first flow holes and that are axially aligned with fuel rods within the fuel assembly.

Abstract: A suction strainer includes a hollow internal core tube and an external filtering surface built around the internal core tube. A plurality of openings are defined through the side wall of the internal core tube core. In some cases the openings through the side wall are constructed and arranged such that there is somewhat less open area near the downstream end than the upstream end of the internal core tube, and the amount of open area tapers between the upstream end and the downstream end. As a result, when liquid is drawn into the internal core tube through the plurality of openings, a substantially uniform inflow distribution may be defined along substantially the entire length of the internal core tube. The internal core tube functions as a rigid structural support for the external filtering surface, enabling the apparatus to withstand post-LOCA hydrodynamic forces.

Abstract: A CRUD collection system for removing deposits from a nuclear reactor fuel rod submerged in pool water. The system includes a sealable collection head for containing a portion of the fuel rod. The collection head includes at least one seal positioned to receive the fuel rod. Also provided is a liquid inlet communicating with an interior portion of the collection head, the inlet is configured to inject a liquid into the interior to displace the pool water therefrom. At least one blade is provided that is positionable in scraping engagement with the fuel rod. Also included is a liquid outlet for eliminating a CRUD sample and the liquid to a filter.

Abstract: A method and an apparatus for deionizing water are disclosed. A condensate in the secondary cooling water system in a PWR nuclear power plant is passed through a mixture of an anion exchange resin and a cation exchange resin having a crosslinking degree of about 12 to 16%. The cation exchange resin has an improved, ion exchange capacity. thereby decreasing the frequency of changing the condensate.

Abstract: A device for measuring gas pressure that is dependent upon the level of a liquid comprises a pressure indicator or sensor (6, 6′) which is connected to an upper part of a tube conduit (7, 7′) which is filled with gas and intended to operate in a liquid mass, said conduit having a lower part connected to an upper part of a vessel (8, 8′) with a volume that is larger than the volume of the tube conduit. The vessel (8, 8′) has an inlet (13) to let the liquid in, which inlet has a cross-sectional area that is smaller than the cross-sectional area of the vessel and that is located near the bottom of the vessel. Therefore, liquid that penetrates into the vessel via the inlet forms a surface whose level in itself in the vessel may vary depending upon the level of the surrounding main liquid mass, however normally without the liquid rising up into the tube conduit (7, 7′) as such.

Abstract: A novel high-purity polymer dispersant and sludge conditioner added to the feedwater entering the secondary side of a nuclear steam generator for minimizing the accumulation of metal-oxide deposits within the nuclear steam generator during the continuing operation of the generator is disclosed. The high-purity polymer is selected from a group consisting of acrylic acid polymer, methacrylic acid polymer, acrylate polymer, methacrylate polymer, copolymers, and terpolymers, acrylate/acrylamide copolymer, acrylate/methacrylate copolymer, terpolymers, and mixtures thereof. Methods of making and applying the polymer dispersant and sludge conditioner are described. Means for removing the metal oxides and polymer from the blowdown stream are disclosed.

Abstract: Migration of radioactive materials from a pressure vessel to a steam system in a nuclear power plant is suppressed by using a dryer (3) provided with corrugated plates (22) having surfaces coated with an inorganic ion-exchange material stable under a condition in which high-temperature water exist, such as TiO2.

Abstract: The present invention aims to reduce the total exposed dose of the workers inside a reactor well during the annual inspection of a nuclear reactor. In order to achieve the above-mentioned aim, the present invention provides a boiling water reactor, comprising a first piping for pouring water of a reactor vessel to a reactor well located above the reactor vessel via a pump and a cooler, a second piping for pouring water of a spent fuel storage pool to the reactor well via a pump and a filter/demineralizer, and a third piping for pouring the water of the spent fuel storage pool to the spent fuel storage pool via the pump and the filter/demineralizer.

Abstract: A system (20) is presented for extraction of debris (22) from a tank (24) of potentially radioactive water (26) in a nuclear-powered energy-generation facility. The system (20) utilizes a subaqueous reversible motor (28), a subaqueous pump (30) magnetically coupled to the motor (28), and a subaqueous filter housing (50) removably coupled to the pump (30). A filter (52) having a metallic filter element (56) is incorporated into the filter housing (50). A control unit (34) is electrically coupled to the motor (28) and determines a rotational direction thereof from outside the tank (24). When the motor (28) is run in a forward rotational direction, the pump (30) produces a forward flow (36′) of water (26), substantially all of which passes through the filter (52) so that debris (22) in the water (26) is entrapped in the filter (52).

Abstract: Apparatus is provided for filtering particulate matter from a fluid flow pumped from a coolant pool for a nuclear reactor. The apparatus comprises a large vessel with an interior chamber in which is rotatably supported a turntable in the form of a rigid basket-like support structure on which a large number of disposable filter cartridges are removably secured. Part of the turntable is a manifold assembly for distributing contaminated fluid received from a central conduit to the inlet side of the filter cartridges in the chamber. The vessel serves as a containment for coolant processed through the filters whereby the cleansed coolant may be conducted outwardly from the vessel through an outlet port and piped back to the pool of origin. Gate means are provided on the vessel in the form of normally closed ball valves which allow, during shut-down of the apparatus, extension, into and through the vessel, of tools to manipulate the turntable within the vessel and to accomplish filter cartridge replacement.

Abstract: Passive aerosol retention apparatus positioned in the connecting vents of a nuclear reactor containment are described. The aerosol retention apparatus minimizes aerosol transport from the lower drywell to the upper drywell of the reactor containment. The retention apparatus includes a substantially cylindrical housing and a flow modulator positioned inside the housing and extending at least partially from a first end to a second end of the housing. The flow modulator includes a helically shaped baffle positioned in the housing so as to be coaxial with the housing. The baffle is coupled at each end to the housing by attachment bars.

Abstract: A maintenance of a suppression pool or spent fuel storage pool in a reactor primary containment vessel of a nuclear power plant includes a cleaning step of a water in the suppression pool and a decontamination step of an interior of the suppression pool, and in the maintenance, the coated film applied on an inner surface of a wall portion of the suppression pool is inspected. These cleaning, decontaminating and inspecting steps are performed by divers while maintaining a water level in the suppression pool.