Abstract: A valve control apparatus for generating an anticipatory output response for controlling a fluid flow in a fluid flow line includes a valve provided inside the fluid flow line, at least one sensor for providing at least one input signal, said at least one input signal responsive to properties of said fluid flow in advance of said valve, and a letdown back-pressure controller receiving said at least one input signal and providing a tunable output signal for selectively opening and closing said valve to vary flow in the flow line responsive to said at least one input signal.

Abstract: A fuel assembly (1) for a boiling water nuclear reactor comprising a plurality of vertical fuel rods (3) which are arranged in spaced relationship between a bottom tie plate (6) and a top tie plate (5). The bottom tie plate (6) is provided with through-holes (6a) for the passage of a coolant (F). Further, the fuel assembly (1) comprises a bottom support (10) which is formed substantially from a downstream and an upstream flat surface (12, 13) and four side surfaces (14). The flat surfaces (12, 13) and the side surfaces (14) form a parallelepiped which surrounds a cavity. A filtering member is arranged in the upstream flat surface (13) and comprises a plurality of through-holes (11).

Abstract: A method for removing oxides from a liquid metal heat exchange fluid following the initial startup of the heat exchange system fixes oxygen by locating an oxygen scavenging material in a drain tank. During initial fabrication and periods of maintenance metal surfaces of the conduits, heat exchange elements and other equipment become coated with an oxide layer. This invention eliminates the need for the sacrificial traps in the circulating system that are used to remove this initial oxide loading by placing an oxygen scavenging material in the drain tank. The drain tank is ordinarily provided to retain the inventory of liquid metal when it is not circulating in the heat exchange volume. A simple drain down of the liquid metal inventory can thereby remove from the liquid metal inventory essentially all of the oxide impurities that usually accompany an initial startup of such a system.

Abstract: In order to determine a concentration of a gas mixture, especially a hydrogen concentration of a containment atmosphere of a nuclear power station, a temperature change resulting from a catalytic reaction is measured. The gas mixture is diluted with a motive gas of known composition. The dilution is carried out by a jet pump.

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: An elongated internal core tube suction strainer supported at its ends for use in a suction system is disclosed as is a suction system comprising the elongated suction strainer in combination with ECCS pipes in various support combinations. The elongated internal core tube suction strainer of this invention is particularly suited for use with boiling water reactor (BWR) and pressurized water reactor (PWR) nuclear power plants. Because of the flexibility of the suction strainer of this invention, the suction strainer can be adapted for use in a variety of reactor plants. The elongated suction strainer has an internal core tube defining a plurality of fluid inlets and an exterior filtering structure defining a plurality of perforations.

Abstract: Metal ions are added to a circuit (20, 30) for the reactor water or feed water of a nuclear plant. This is accomplished by dissolving a soluble metal compound the counter-ion of which is possible to decompose to gaseous products and water in water in a reaction vessel (41) in an equipment arrangement (40). The solution is subsequently conducted to a series of vessels (42) for the decomposition of the counter-ion. The solution is then possibly transformed to a mixture or a slurry which is conducted to a vessel (43) for degassing the gaseous products before the addition to the circuit (20, 30) for the reactor water or feed water.

Abstract: When hydrogen is generated within the containment of a nuclear power station, its containment atmosphere must be inerted. An undesired pressure buildup within the containment is prevented during such inerting with the apparatus and the method. It is possible to vent and inert the containment atmosphere simultaneously. A reversible activity holdup device is provided, which makes it possible to vent the containment atmosphere, without radioactive material being released into the surroundings. It is thereby also possible for the containment of a nuclear power station to be inerted even as a preventive measure, so that the safety of the nuclear power station plant is markedly increased.

Abstract: A nuclear fuel assembly for use in a pressurized water reactor comprising a top nozzle and a bottom nozzle, fuel rods loaded and supported by grids in cells thereof and interconnected between a lowermost grid and the top nozzle, and a filter member interposed between the lowermost grid and the bottom nozzle.

Abstract: In a fuel assembly for a nuclear reactor and a process for the production of a screen plate for a foot of the fuel assembly, a particle trap is disposed in the foot of the fuel assembly in order to protect fuel rods of the fuel assembly from damage by foreign bodies. The particle trap is formed of a one-piece screen plate into which holes in the screen plate are worked by electrochemical material erosion. It is thereby possible to produce holes with geometrical dimensions and shapes which can only be achieved with difficulty in a casting process or by mechanical machining.

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 cation exchanger is loaded only with radioactive cations by repeatedly converting the non-bivalent, inactive cations into anionic complexes and flushing the complexes out of the cation exchanger. The cation exchanger, which may be integrated in a primary system of a nuclear power plant, is connected to a feed line for a complexing agent and to a discharge line through which the anionic complexes are flushed from the exchanger.

Abstract: A BWR emergency core cooling system suction strainer. The strainer comprises corrugated metal screen material formed of alternating ridges and furrows with flat chordal lands and flat side walls interconnecting the lands; and an elongated frame with arcuate end support portions shaped to accommodate the ridges and furrows. The flat side walls merge slightly toward one another in a substantially radially inwardly direction and diverge slightly away from one another in a substantially radially outwardly direction to permit release of debris from the screen surface while providing increased screening area for a given volume of strainer.

Abstract: Although a chelating agent solution having radioactive contaminants is solidified by mixing with cement and then stored, a vast storage place is required for storing an enormous amount of chelating agent solution. When such a chelating agent solution is treated with an ion-exchange resin, a large amount of ion-exchange resin is required, and a large amount of ion-exchange resin having radioactive contaminants is produced. The present invention thus provides a method of treating a chelating agent solution having radioactive contaminants, which can significantly decrease the amount of the chelating agent solution having radioactive contaminants, and which, when an ion-exchange resin is used, can significantly decrease the load on the ion-exchange resin without producing a large amount of ion-exchange resin having radioactive contaminants.

Abstract: A strainer for filtering a pumped fluid has a strainer body having a wall provided with fluid inlet perforations in an outer surface, a surface cleaning scraper or brush in juxtaposition with the outer surface, and a drive operatively connected to the surface cleaner for moving the surface cleaner over the outer surface for removing accumulated debris. At least one nozzle is oriented towards the cleaned outer surface of the strainer body for directing a jet of liquid against the perforations to assure that the perforations are clear. The strainer is thus self-cleaned continuously without requiring a back wash operation, allowing continuous flow through the strainer.

Abstract: A method for operating the LOMI decontamination process in a regenerative manner. The method incorporates an initial injection of a dilute LOMI solution (vanadous formate, picolinic acid and sodium hydroxide) into a decontamination circuit followed by operation of a small cluster of cation exchange columns during the decontamination process. The cation exchange resin is used to remove metals in the same manner as in prior decontamination processes but operation of the cation exchange resin is continued to allow picolinic acid initially bound to the cation exchange resin to be released and recycled to the LOMI solution. Operation of the cation exchange columns ceases after the picolinic acid has been released but before the metals (e.g. sodium, iron and vanadium) are released back to the LOMI solution. The cluster of cation exchange columns are operated according to a sequence wherein one column is releasing picolinic acid while another is binding picolinic acid.

Abstract: In a fuel assembly for a nuclear reactor and a process for the production of a screen plate for a foot of the fuel assembly, a particle trap is disposed in the foot of the fuel assembly in order to protect fuel rods of the fuel assembly from damage by foreign bodies. The particle trap is formed of a one-piece screen plate into which holes in the screen plate are worked by electrochemical material erosion. It is thereby possible to produce holes with geometrical dimensions and shapes which can only be achieved with difficulty in a casting process or by mechanical machining.

Abstract: A fuel bundle assembly for a nuclear reactor includes a modified channel that improves pressure drop performance and a handle assembly that includes structure for preventing a broken end plug from escaping the fuel bundle. In modifying the channel, one approach is to vary the outside dimension of the fuel channel along the length of the channel, but maintain a constant channel wall thickness. Another approach is to maintain the external dimensions of the fuel channel and vary the wall thickness along the length of the channel. The handle assembly replaces the conventional upper tie plate and is provided with structure for preventing debris such as a broken fuel rod end plug from escaping the fuel bundle. The structure preferably includes a plurality of gridwork cross members forming a substantially square grid including gridwork windows that are sized smaller than the fuel rod end plugs.

Abstract: A suction strainer for straining water from the emergency suppression pool of a boiling water reactor includes a plurality of stacked, perforated disks having an internal core with a minimum internal radius r(x) that decreases with increased distance from the intake of the strainer, so that the core has a tapered profile. Internal radius r(x) may vary linearly or exponentially or a combination of both. The stacked, perforated disks each include a first surface that faces in the direction of the intake and a second surface, that faces away from the intake. A circumferential band may connect the first and second surfaces together.

Abstract: A fuel bundle for a nuclear reactor includes a plurality of fuel rods extending between upper and lower tie plates, and a filter plate seated on the lower tie plate. The filter plate includes a substantially planar plate having a plurality of fuel rod holes in a predetermined array, the plate having web areas between the fuel rod holes which are formed with a plurality of smaller debris filter holes. At least one of the web areas is formed to include a spring tab pivotable out of the plane of the plate so that in the event of debris overload, coolant can bypass the smaller debris filter holes.

Abstract: Method and apparatus for enhancing removal of corrosion products from a nuclear reactor piping system. A reagent is supplied into a multi-part reactor piping system to react with the corrosion products therein. The corrosion products dissolve into the reagent to define a contaminated solution. The contaminated solution is brought into contact with an ion exchange resin bed that absorbs the corrosion products from the contaminated solution to define a reagent-containing contaminant-free solution. In this regard, a circulation pump having a predetermined net positive suction head (NPSH) interconnects the system with the resin bed for pumping the contaminated solution from one part of the reactor piping system and into contact with the resin bed and thereafter pumping the contaminant-free solution from the resin bed and to another part of the reactor piping system to remove the corrosion products.

Abstract: A system for filtering liquids like cooling water and emergency cooling water in nuclear power stations and other industrial plants wherein a continuous circulation of a coolant or other liquid has to be secured. The system comprises a first filtering surface and a first filtrate space which is at least partially limited by the first filtering surface and at least one further filtering surface with a second filtrate space which is at least partially limited by a filtering surface. A filtrate outlet channel is connected to the first filtrate space and a siphon connects the filtrate spaces.

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 self-cleaning, self-propelled strainer designed for installation in boiling water reactor suppression pools. The strainer is designed to prevent strainer clogging and subsequent loss of the emergency core cooling system flow during a postulated design basis loss-of-coolant accident. This self-cleaning strainer is driven by a turbine placed in the strainer flow path. The turbine drives rotation of a brush-and-plow arrangement. The wiping action of the brush and the centrifuging action of the plow remove insulation debris and other particulate matter which might be generated by the LOCA, thereby preventing the strainer from plugging.

Abstract: In a nuclear fuel rod assembly including a plurality of fuel rods and at least one water rod held together in a bundle, and wherein end plugs at the lower ends of the fuel rods and the at least one water rod engage a lower tie plate, an improvement wherein the end plug at the lower end of the at least one water rod is hollow and includes a multi-diameter flow metering bore for regulating coolant flow into the water rod.

Abstract: A filter for a control rod drive of a nuclear reactor is adapted to be attached to a connector extending upwardly from a piston. The filter includes a base portion and a perforated filter portion, the base portion having a radially open recess adapted to receive the connector in a sideways movement. The recess is bordered by a pair of spring arms of substantially square cross-section which are adapted to resiliently grip the connector upon installation.

Abstract: A maintenance cover for use in a nuclear reactor including a pump deck having at least one pump diffuser opening is described. The cover includes, in one embodiment, a substantially cylindrical member having a first end and a second end. The first end has a diameter larger than the diameter of the pump diffuser opening. The substantially cylindrical member includes a substantially cylindrical frame having a plurality of window openings formed therein. Grating is secured to the frame and extends over the window openings. The cover further includes an end member secured to and positioned over the second end of the substantially cylindrical member. The end member also includes grating. A handle is secured to the substantially cylindrical member.

Abstract: A device for filtering water to at least one emergency cooling system in a nuclear power plant of the type comprising a reactor arranged in a containment which substantially consists of an upright, suitably cylindrical container whose bottom part forms a pool for collecting water formed by condensation of steam present in the containment, the condensation pool including a number of back-flushable containers filter water which is taken from the pool and, if required, is supplied to nozzles in the emergency cooling system in order to cool the reactor core in the event of an inadmissible temperature rise therein, each strainer having a shape of a housing with at least one, suitably cylindrical, apertured strainer wall through which the water can flow from the outside and into the housing, and being connected, by a first conduit passing through the container wall, to a suction pump disposed outside the container wall, as well as connected to a secondary conduit for supplying wash water to the interior of the hous

Abstract: Medical isotopes are produced using a lower power, low cost nuclear reactor which permits the use of all the fission products produced in the reactor. Medical isotopes such as Molybdenum-99 are produced in a reactor operating at a power of 100 to 500 kilowatts.

Abstract: A filter adapter and filter cartridge for a filter assembly for removing particulate matter from an aqueous flow by means of a filter vessel having a support housing, a removable top, an input port for the aqueous flow, an exit port for the aqueous flow and an internal seal. The filter assembly includes a filter adapter configured similarly to the housing and sized to be substantially entirely received within the housing and sealingly engage the internal seal of the housing. A filter cartridge is configured similarly to the filter adapter and is sized to be substantially entirely received within the filter adapter and to simultaneously engage the filter vessel top and sealingly engage the filter adapter outlet. A biasing spring is located between the filter cartridge and the filter adapter.

Abstract: Disclosed is a transportation and storage assembly for transporting and storing nuclear fuel rod assemblies. The transportation and storage assembly includes a basket assembly (24) designed for failed nuclear fuel rod assemblies, or a basket assembly (122) designed for undamaged nuclear fuel rod assemblies. The basket assemblies (24, 122) are inserted into a canister (22). The canister (22) includes a shell (26) that receives and surrounds the basket assemblies (24, 122), and lids (28, 96) that enclose the shell (26). The basket assemblies (24, 122) include a plurality of apertured plates (36, 124) interconnected by structural members (42, 88) that maintain the plates (36, 124) in a spaced apart relationship, axially aligning the apertures (38, 126) in the plates (36, 124). In the basket assembly (24) for failed nuclear fuel rod assemblies, a container (44) is inserted into a row of axially aligned apertures (122), having a drain passage (104).

Abstract: The lower tie plate grid includes cylindrical bosses and webs interconnecting the bosses for supporting nuclear fuel rods and defining flow channels through the grid for flowing coolant upwardly about the fuel rods. The grid includes shaped body members having flow openings, the members being disposed in each of the flow channels. In one form, the members define with the side walls of the bosses and webs a debris retention zone. In another form, sets of generally parallel, laterally spaced bars are disposed at discrete elevations in the flow channels. The bars are orthogonally related to one another whereby the effective debris catching area is defined by the openings through the crossed bars in plan, while the coolant flow area comprises essentially the space between each set of bars.

Abstract: A strainer device for filtering water to an emergency cooling system in a nuclear power plant includes a housing or tube having a perforated or apertured strainer wall through which water may flow from the outside and into the interior of the housing in connection with the regular filtration of water taken in. A water-receiving accumulator tank is connected to the cavity of the strainer housing and a source of pressurized gas is connected to the tank in order, if required, to feed pressurized gas into the tank so as to momentarily force water out therefrom and into the cavity of the strainer housing while backflushing the same.

Abstract: A fuel bundle and lower tie plate assembly for a nuclear reactor includes a plurality of fuel rods supported between an upper tie plate and a lower tie plate assembly. The lower tie plate assembly includes an upper grid portion and a lower body portion, the upper grid portion having a plurality of fuel rod supporting bosses interconnected by a plurality of webs thus forming flow openings between the bosses. The body portion includes an inlet nozzle and a peripheral wall extending between the bottom nozzle and the upper grid portion to define a flow volume therein. A debris catcher is located within the flow volume and includes a pair of superposed plates, the plates each having a plurality of holes of substantially the same size, shape and pitch, but wherein the holes of one of the pair of plates are offset from the holes of the other of the pair of plates by one half the hole pitch.

Abstract: A debris resistant fuel rod sleeve that is received over the lower end of a fuel rod. The sleeve extends above the top of the lowermost spacer grid. Openings are spaced apart around the circumference of the sleeve to correspond to the location of hard stops in the spacer grid. The hard stops are received in the openings and retain the sleeves in position during operation and during reconstitution or recaging if necessary. The outboard side of the peripheral sleeves may be provided with top and bottom lead-in features to prevent hang-ups.

Abstract: A method for retrofitting an irradiated nuclear fuel assembly including removing a portion of the inlet nozzle and installing a debris filter.

Abstract: The lower tie plate grid includes cylindrical bosses and webs interconnecting the bosses for supporting nuclear fuel rods and defining flow openings through the grid. Coolant flows through the flow openings for flow upwardly about the fuel rods. The grid includes upper and lower portions and a screen is disposed between the upper and lower grid portions upon assembly with the bosses and webs of the respective upper and lower grid portions in registry with one another. The grid portions are welded to one another whereby the apertured screen serves to separate debris from the coolant flowing through the flow openings. The screen has openings in registry with the openings defined by the bosses for receiving the end plugs of the fuel rods.

Abstract: A nuclear reactor having a chemical decontamination clean-up system is provided in which every component of the chemical decontamination clean-up equipment which processes radioactive fluids is located within a shielded room of an existing on-site support building. Those components of the clean-up system not in direct contact with radioactive fluids are housed in portable trailers. The decontamination clean-up system is designed to provide for adequate shielding to minimize personnel exposure and also incorporates a modular design for component transportation and storage.

Abstract: A nuclear fuel assembly debris filter. Each fuel rod has a ring attached to the lower end cap. The rings are shaped and sized to define a space between the lower end cap and ring such that the space serves to trap, or filter, debris before it reaches the elevation of the fuel cladding. The rings may be circular, elliptical, or any suitable shape that provides the desired filtration effect.

Abstract: A unitary one-piece lower tie plate grid has a lower portion and an upper portion for supporting the fuel rods. The lower tie plate grid includes cylindrical boss portions extending upwardly from the lower grid portion and arranged in square matrices for receiving the lower end plugs of the fuel rods. Web portions extending upwardly from the lower tie plate portion interconnect the boss portions along the sides of the matrices. The lower grid portion includes a plurality of openings which open into the flow spaces defined by the convex portions of the bosses and the webs within each square matrix of the upper portion of the tie plate. Coolant flows through the openings into the flow spaces for further flow upwardly about the fuel rods. The openings are radiussed adjacent their lower ends and have divergent side walls downstream of a throat area to define a flow venturi.

Abstract: In a boiling water reactor fuel bundle, a three dimensional debris catching grid construction is placed within the flow volume defined by the lower tie plate assembly between the inlet nozzle and upper fuel rod supporting grid. A perforated plate is utilized having round holes as small consistent with the prevention of inadvertent closure due crudding and a hole pitch consistent with mechanical integrity requirements. The perforated plate is placed in a three dimensional construction such as a dome, cylinder, pyramid, inverted pyramid or corrugated construction spanning the flow volume of the lower tie plate assembly. As a consequence of this three dimensional grid construction, the total flow through area of the perforations in the metal plate does not introduce appreciable pressure drop in the lower tie plate assembly between the inlet nozzle and the rod supporting grid.

Abstract: The invention relates to a volume delimitation tank (1) for preventing or limiting contamination of the surrounding liquid medium when working with contaminated parts. The volume delimitation tank (1) comprises a sack or channel which constitutes at least the substantially vertical walls (1a-d) of the tank and is made of a material which is capable of being folded, which is radiation-resistant, and resistant to puncture. The walls (1a-d) can be provided with fold notches (27) to obtain a well-defined folding when, for example, lowering at least one wall portion (1a-d) for passing objects out of the tank (1). The walls (1a-d) of the tank (1) are arranged at a bottom part (9). Cleaning equipment (16) is arranged inside the tank (1) for continuous cleaning of the contained volume.

Abstract: A fuel bundle and lower tie plate assembly for a nuclear reactor includes a plurality of fuel rods supported between an upper tie plate and a lower tie plate assembly, the lower tie plate assembly including an upper grid portion and a lower body portion, the upper grid portion having a plurality of fuel rod supporting bosses interconnected by a plurality of webs thus forming flow openings between the bosses. The body portion includes an inlet nozzle and a peripheral wall extending between the bottom nozzle and the upper grid portion to define a flow volume therein. A debris catcher, including a plurality of perforated tubes, is incorporated into the lower tie plate assembly, such that one of the tubes is in abutment with a respective lowermost end of each of the plurality of fuel rod supporting bosses.

Abstract: A reactor coolant debris filter for insertion within a nuclear fuel assembly support.

Abstract: A method for retrofitting an irradiated nuclear fuel assembly including removing a portion of the inlet nozzle and installing a debris filter.

Abstract: A fuel assembly for a light-water nuclear reactor includes a plurality of vertical fuel rods (10) which are arranged, in spaced relationship in the lateral direction, between a bottom tie plate (11) and a top tie plate (12). The bottom tie plate and the top tie plate are provided with through-holes (35) for inlet and outlet of coolant for the fuel rods. Below the bottom tie plate, in the flow path of the water, a debris catcher (36) is arranged which includes helical springs (40) that are arranged in a frame having at least two ends (37, 38) in the form of substantially parallel plates, the flat sides of which are interconnected via pins (39). The pins are arranged in spaced relationship in at least two rows between the ends in such a way that the springs, in spaced relationship or adjacent to each other, can be fixed between the rows of pins in one or more layers.

Abstract: A unitary one-piece lower tie plate grid has a lower portion and an upper portion for supporting the fuel rods. The lower tie plate grid includes cylindrical boss portions extending upwardly from the lower grid portion and arranged in square matrices for receiving the lower end plugs of the fuel rods. Web portions extending upwardly from the lower tie plate portion interconnect the boss portions along the sides of the matrices. The lower grid portion includes a plurality of openings which open into the flow spaces defined by the convex portions of the bosses and the webs within each square matrix of the upper portion of the tie plate. Coolant flows through the openings into the flow spaces for further flow upwardly about the fuel rods. The openings are radiussed adjacent their lower ends and have tapered divergent walls opening into the flow spaces. In another form, the openings have a step intermediate the upper and lower surfaces of the lower grid portion to define a minimum cross-sectional flow area.

Abstract: A fuel assembly for a light-water nuclear reactor includes a plurality of vertical fuel rods (12) which are arranged, in spaced relationship in the lateral direction, between a bottom tie plate (13) and a top tie plate (14). The bottom tie plate and the top tie plate are provided with through-holes (17a) for inlet and outlet of coolant for the fuel rods. Below the bottom tie plate, in the flow path of the water, a debris catcher (18) is arranged. The debris catcher includes at least one helical spring (19) which is fixed in a holder permeable to the coolant and defining at least one slot which is formed as a plane spiral (30) or several concentric annular slots (23, 27) in which slot/slots the helical spring/helical springs is/are arranged.

Abstract: A process for selectively removing metal values which may include catalytic values from a mixture containing same, wherein a magnetic particle is contacted with a liquid solvent which selectively dissolves the metal values to absorb the liquid solvent onto the magnetic particle. Thereafter the solvent-containing magnetic particles are contacted with a mixture containing the heavy metal values to transfer metal values into the solvent carried by the magnetic particles, and then magnetically separating the magnetic particles. Ion exchange resins may be used for selective solvents.

Abstract: A back-flushable strainer is used for filtering water to an emergency cooling system in a nuclear power plant having a reactor arranged in a containment whose lower part forms a condensation pool in which the strainer is mounted. The strainer has a suitably cylindrical strainer wall having a plurality of perforations through which the water flows from the outside and in when filtering, while the direction of flow is the reverse in backflushing. A number of wings are arranged on the outside of the strainer wall, dividing a residue or fibre mat built up on the outside of the strainer wall into a number of sections which separately are more easily released than a continuous, circumferential fibre mat.