Abstract: An apparatus for loosening and removing sludge and other impurities from the interior of a heat exchanger vessel which may be the secondary side of a nuclear steam generator is disclosed herein. The apparatus generally comprises a nozzle having a first end that is detachably mountable into an access opening such as a sludge lance port in the secondary side of the generator, and a second end that extends into the interior of the secondary side at a 30 degree downward angle relative to the tubesheet in the vessel for minimizing the stresses applied to the heat exchanger tubes, and for uniformly reflecting the pulse back up toward the upper portions of the secondary side. A pulse generator is operably connected to the nozzle which has a controller for controlling the power level of the pulses generated. To further minimize such peak tube stresses, the pulse generator includes a pulse flattener, and the second end of the nozzle is aligned down the main tube lane.

Abstract: A nuclear reactor includes a spaced sidewall and a core shroud defining a flow passage for channeling a coolant. A foreign object separator includes an arcuate endwall extending from the sidewall, with the core shroud including an intermediate portion spaced from the endwall to define an annular inlet for receiving coolant from the flow passage. The core shroud also includes a distal end spaced from the endwall to define a throat. A separator member has a proximal end joined to the endwall, and a distal end spaced from the core shroud to define an outlet. The distal end of the separator is spaced from its proximal end for allowing the coolant from the throat to impinge against the separator member for turning the coolant prior to discharge from the outlet and using centrifugal force to separate any foreign objects of predetermined size from the coolant. The separated foreign objects are retained adjacent to the separator member proximal end.

Abstract: Both a system and a method for removing sludge and debris from the interior of the secondary side of a nuclear steam generator is disclosed. The method comprises the steps of introducing a sufficient amount of water in the secondary side to submerge at least the tubesheet, generating a succession of shock waves in the water by means of pulses of pressurized gas to create shock waves that loosen the sludge and debris, and vertically flushing the interior of the secondary side by suctioning water off from the bottom portion of the steam generator while simultaneously forcefully spraying water from the top portion of the generator over the bundle of heat exchanger tubes in order to remove the sludge and debris loosened by the shock waves.

Abstract: A method for loosening and removing sludge and debris from the vessel of a heat exchanger, such as the secondary side of a nuclear steam generator, is disclosed herein. The method generally comprises the steps of providing a sufficient volume of a liquid, such as water, into the steam generator so that the lower portion which includes the tubesheet is submerged, and then generating a succession of pressure pulses within the water from one or more pressure pulse generators wherein each pressure pulse creates shock waves that exert momentary forces throughout the submerged portion of the generator of a magnitude sufficient to loosen the sludge and debris, but safely below the yield and fatigue limits of the heat exchanger tubes and other components within the generator. The pressure pulses commence as soon as a sufficient amount of water is introduced into the steam generator to submerge the tubesheet, and continue all the way through the draining of the steam generator.

Abstract: The present invention relates to intermittently introducing, under carefully controlled conditions, an inert gas, into at least the channel head primary coolant water outlet side of steam generators during the drain-down of a nuclear-powered steam generating system. Predetermined quantities of such gas are introduced into open ends of the inverted U-tubes which terminate at the tubesheet in the channel heads to thereby alleviate the propensity for formation of vacuum pockets at the tops thereof, and at the same time to provide that water columns defined severely near their tops by the water within each such tube and collectively near their bottoms by the water extending downward through the steam generator channel head, are not disrupted by the inadvertent formation of a gas/water interface formed in the general vicinity of the tubesheet and resulting from the flooding of the underside thereof with said gas.

Abstract: An articulated lance for cleaning sludge located between steam generator tubes is disclosed. A plurality of radius blocks are attached to the end of manipulator member and are actuatable by a cam assembly to form an arc permitting the lance to be received between adjacent tubes within a tube bundle. A plurality of fluid passageways interconnect a fluid inlet on the manipulator member with one or more outlet orifices adjacent the end of the lance. The outlet orifices are positioned outwardly with respect to the end of the manipulator member so that fluid passing therethrough can be directed to impinge upon sludge surrounding the tubes. A spring backing place biases the radius blocks and the manipulator member back into the same plane upon deactuation of the cam assembly.

Abstract: Built-up deposits on the top surface of a tubesheet and on adjacent tube sections in a tube bundle heat exchanger are removed by inducing vigorous turbulent flow of cleaning liquid radially along the surface of the tubesheet by repetitively and periodically injecting gas pulses into the liquid to form an expanding and retracting gas bubble proximate the plate center. The gas pulse rise time is smoothed by controlling the actuation time of a discharge valve and by a surge volume downstream of the valve to thereby avoid harmful pressure shock waves in the heat exchanger. The cleaning liquid is recirculated through an external filter loop to remove suspended foreign materials dislodged by the turbulent flow.

Abstract: A method for loosening and removing sludge and debris from the vessel of a heat exchanger, such as the secondary side of a nuclear steam generator, is disclosed herein. The method generally comprises the steps of providing a sufficient volume of a liquid, such as water, into the steam generator so that the lower portion which includes the tubesheet is submerged, and then generating a succession of pressure pulses within the water from one or more pressure pulse generators wherein each pressure pulse creates shock waves that exert momentary forces throughout the submerged portion of the generator of a magnitude sufficient to loosen the sludge and debris, but safely below the yield and fatigue limits of the heat exchanger tubes and other components within the generator. The pressure pulses commence as soon as a sufficient amount of water is introduced into the steam generator to submerge the tubesheet, and continue all the way through the draining of the steam generator.

Abstract: A method and apparatus, comprising a tool having a clam shell design, for sealing the interface volume between the internal wall of a reactor pressure vessel and submerged piping that penetrates the wall, and for cleaning the interface volume using a series of hydraulic and pneumatic operations. The tool is operable from a remote suface location, using a robotic arm for fine positioning, to clamp around the penetrating pipe. Hydraulic nozzles compressed air and mechanical brushes on the tool may be used to dislodge sediment in the interface volume.

Abstract: A water cannon, having an air gun disposed within its breach, for explosively discharging a quantity of water from the muzzle, which may include a constricted directional nozzle, to dislodge sludge from the tube sheet of a heat exchanger, and a method of cleaning the tube sheet of a heat exchanger are disclosed.

Abstract: The process involves injecting water into the guide tube (6) from the instrumentation room (10) and generating suction within the guide conduit (8) from the outlet end of this conduit located level with the upper face of the core support plate (5). The suction rate Q2 is higher than the injection rate Q1, the ration of these rates being at least equal to the ratio between the inlet cross-section of the guide conduit (8) and the inner cross-section of the entry sleeve (7) of the guide tube (6). The cleaning device comprises a bell (34) in which the suction is generated and which comes to bear on the upper surface of the support plate (5) via a gasket (35).

Abstract: A nuclear power plant includes a containment for containing activity carriers. An outlet in the form of an excess pressure safety device leads out of the containment. A filter connects the outlet to the atmosphere. The filter includes a container, a washing fluid disposed in the container, a Venturi scrubber being integrated in the container and connected to the outlet, the container having an upper region with a gas outlet, and a stack connected to the gas outlet.

Abstract: An apparatus for storing nuclear reactor fuel assemblies in a water pit, includes means for holding an end of a fuel assembly and for transporting the fuel assembly through the water pit, a vessel disposed in the water pit having a closed bottom and an open top in communication with a water space in the water pit forming a vertically elongated well in the vessel for at least partly receiving a fuel assembly, a suction connection in communicaton with the well through the closed bottom of the vessel, a suction pump connected to the suction connection, a shielding container, and a filter disposed in the shielding container and connected to the pump for collecting deposits suctioned from the well.

Abstract: A process and apparatus for decontaminating parts of nuclear power plants which are contaminated with radioactive material, wherein surface layers are removed from the parts. The parts to be decontaminated are treated with a jet of pressurized water which contains a granular abrasive and which may contain admixed air. The mixed effluent consisting of water, abrasive and detached particles is separated into an aqueous phase and a sludge phase, the sludge phase is dried, and the resulting dry material is separated into abrasive and particles smaller in diameter than the abrasive. The purified abrasive is recycled to the water for forming the jet of water under pressure, and the separated particles are made available for safe disposal.

Abstract: Device for flushing out a lance-housing tube in a reactor pressure vessel of a boiling-water reactor and for aligning therein a dry LVD lance which partly protrudes with a pressure-tight lance passthrough from an end flange on the lance-housing tube of the reactor pressure vessel, includes a tubular housing surrounding from below a part of the lance protruding from the reactor pressure vessel and sealed by a lance protection tube, the tubular housing being fastenable to the end flange; and a piston arranged in the tubular housing underneath the sealed lance, the piston being vertically displaceable and rotatable.

Abstract: A water cannon, having an air gun disposed within its breach, for explosively discharging a quantity of water from the muzzle, which may include a constricted directional nozzle, to dislodge sludge from the tube sheet of a heat exchanger, and a method of cleaning the tube sheet of a heat exchanger are disclosed.

Abstract: A cleaning apparatus for atomic reactor control rod driving means (CRD) comprises a water tub for washing a CRD, rails laid within the water tub, a truck for loading the CRD installed on the rails, a CRD clamp unit mounted on the truck having means for rotating the CRD in the circumferential direction as well as for clamping the CRD, a CRD disassembling and assembling grapple unit installed within the water tub to clamp the CRD and move the same sideways, an outer-surface washing nozzle for washing an outer tube surface and strainer of the CRD, a lance installed within the water tub, which is insertable into the tubes of the CRD and which is equipped with a nozzle assembly to spray the washing water onto the inner surface of the tubes, a filter washing nozzle unit installed within the water tub to spray the washing water onto a cylindrical filter of the CRD, a washing-water circulating pipe connected to the water tub, and a filter unit provided on a portion of the pipe, to filter the washing water.

Abstract: Injection device used when a reactor is shut down to remove radioactive substances from within the gap between the internal piping and the inside of the nozzles of a RPV by injecting fluid towards the inside of these nozzles. The injection device is equipped with an injection nozzle that injects fluid towards the end of the gap, a casing that supports this injection nozzle, a suspension mechanism whereby the casing is movably suspended from above the RPV, a water feed device that supplies high-pressure fluid to the injection nozzle, a sensor or the like that senses when the casing is positioned directly above the internal piping and a fixing mechanism that temporarily fixes the casing to the inside wall of the RPV.

Abstract: A non-corrosive, non chemical cleaning process for tube bundle heat exchangers develops and physically transmits kinetic energy in the form of a vigorous, high volume "water slap" to dislodge internally accumulated contaminants. A plurality of injectors periodically inject discrete quantities of pressurized inert nitrogen into the heat exchanger downcomer annulus, near the steam generator bottom, and in response to the expanding gas bubble the water column established in the tube bundle is accelerated upwardly. A rapid displacement of a body of water causes the surface of the water to slap debris from components in its path. The water column level is established slightly below the bottom of a tube support structure, and the rapid rise of the water surface impacts the bottom of the structure and is forced through the water flow passageways where the fluid flow acceleration pressures dislodge the accumulated debris.

Abstract: A method and apparatus for removing from the tube sheet and transfer tubes of a nuclear steam generator sludge deposits which occur from the use of all volatile treatment water chemistry. A continuously activated suction apparatus maintains at a low level the water/sludge inventory on the tube sheet. A high pressure first water lance is oscillated and stepped inwardly along the central tube lane of the generator to dislodge the sludge from the tube plate and heat exchange tubes. After this lance has been stepped inwardly to a predetermined position, a low pressure second water lance is activated and periodically advanced to a position just short of the first lance and functions both to dislodge sludge and to form a water barrier which prevents redeposition of sludge in the clean area.

Abstract: The present invention relates to an improved method of cleaning a nuclear steam generator by removing the buildup of deposits which accumulate on the upper tube support plates, on the heat exchanger tubes, on flow holes in the support plates and between the support plates and heat exchanger tubes, and on other secondary side surfaces of a heat exchanger vessel through utilization of a repetitive shock wave induced in the deposits. The shock wave serves to effectively and safely loosen the products of corrosion and other elements which settle on these surfaces of the heat exchanger vessel and thereby facilitiates their easy removal through flushing and vacuuming the vessel. The shock waves are induced by air-gun type pressure pulse shock wave sources or pressurized gas-type pressure pulse shock wave sources.

Abstract: The overflow in the secondary of a steam generator of a nuclear-reactor plant, which occurs when one or more primary tubes conducting the coolant are ruptured, is controlled. The secondary of the steam generator, which contains the water that is converted to steam, is connected through valves to the pressurizer relief tank. The level of the liquid in the shell is monitored. An alarm is sounded when the level of the liquid in the generator reaches a predetermined height alerting the operator. When the level reaches a greater height, the valves are opened and the liquid in the shell is discharged into the pressurizer relief tank. The liquid in the tank is discharged into the containment sump when a disc is ruptured. The time taken after the rupture is 30 minutes as mandated by safety regulations. If, after the liquid in the shell reaches the level at which the valves are opened, the level drops to a height at which steam may be injected into the pressurizer relief tank, the valves are automatically closed.

Abstract: A debris trap is mounted within a bottom nozzle of a fuel assembly so as to capture and retain debris carried by coolant flowing from the lower core plate openings of the nuclear reactor to the fuel assembly. The trap includes a hollow enclosure disposed below the bottom nozzle adapter plate and between the corner legs thereof. The enclosure is composed of upper and lower walls and inwardly inclined side walls which space apart the upper and lower walls and interconnect their peripheries so as to form a debris capturing and retaining chamber within the hollow enclosure. The walls are composed of a material, such as wire mesh screen and/or perforated plate, which is permeable to liquid coolant but impermeable to debris. Openings are defined in the bottom wall of the enclosure aligned with the flow openings of the core plate. Two embodiments of features are provided for capturing debris and diffusing coolant flow within and through the trap.

Abstract: A sludge lancing method comprises providing a lancing nozzle and a barrier nozzle for respectively emitting cleaning and barrier streams of fluid along two channels between columns of heat exchange tubes in a nuclear steam generator vessel, the two channels being spaced apart by at least two columns of tubes. The barrier stream prevents dislodged sludge from being moved laterally past it into previously cleaned areas. The streams may be rotated between the center and the periphery of the tube sheet. The barrier nozzle comprises three jets angularly disposed with respect to one another for increased coverage of the barrier channel.

Abstract: Structures are constructed and arranged on a camp site to provide shelter to evacuees seeking survival, as a GROUP, in case of a nuclear attack on or near their city. The construction, disposition, arrangement and shapes of the structures are such that people inside these structures are not affected by the blast of the nuclear explosion, for peak overpressure levels well above those which conventional structures cannot survive. The structures and the camp site are equipped to provide the elimination of fallout dust in a short time so as to bring the total exposure of the evacuees to radioactivity levels low enough to be safe, until the radioactivity within miles has decayed down to levels acceptable for long time exposure. The sheltering structures are interlinked to provide a quasi normal indoor way of life during the period of necessary confinement of the evacuees, so that no evacuee feels the urge to leave the protection provided within the compound against the surrounding grounds radioactivity.

Abstract: A steam generator recirculating system for use with the secondary coolant of the steam generators of a pressurized water nuclear reactor is comprised of two separate recirculation loops. Each loop contains a common discharge line into which a secondary coolant discharge line and blowdown discharge line from at least one steam generator feeds. The common discharge line contains a recirculating pump and a heat exchanger, with bypasses provided about each. The common discharge lines discharge into branch feedlines back to the steam generators. The system may also be used as a blowdown system leading to a steam generator blowdown processing system and may include a water purification means and used to purify the secondary coolant water. Cross-connecting lines are provided to permit optional use of a particular loop with various steam generators.

Abstract: The present invention relates to an improved method of cleaning a tube bundle heat exchanger by removing the buildup of sedimentation or "sludge" which accumulates in the bottom or at other elevations of a heat exchanger vessel through utilization of a repetitive shock wave induced in the liquid layer above the sludge. The shock waves are induced by air-gun type pressure pulse shock wave sources or pressurized gas-type pressure pulse shock wave sources. The shock wave serves to effectively and safely loosen the products of corrosion and other elements which settle at the bottom of the heat exchanger or steam generator and thereby facilitates their easy removal through flushing and vacuuming the vessel.

Abstract: A method and means for continuously introducing nitrogen into the primary coolant side of each steam generator during drain-down of a nuclear powered steam generating system is described, which will prevent the forming of a vacuum at the tops of the inverted U-tubes of the generators, thus to allow continuous drain-down of the water from within the tubes.

Abstract: The present invention relates to an improved method of cleaning and removing the products of corrosion, oxidation and sedimentation which occur within and become attached to the walls of the interior of heat exchanger tubes which are located within a pressure vessel such as a tube bundle heat exchanger, boiler, condenser or the like, through utilization of a repetitive shock wave induced into a liquid which is placed within the tubes and then subsequently flushing the tubes. The shock wave serves to effectively and safely loosen the products of corrosion, oxidation and sedimentation which are located within or settle on the walls of the interior of the heat exchanger tubes, and thereby facilitates their easy removal through flushing and vacuuming the vessel. The shock waves are induced by air-gun type pressure pulse shock wave sources or pressurized gas-type pressure pulse shock wave sources.

Abstract: A ventilation system for a storage or transfer canal for radioactive materials comprises a series of air emitting nozzles spaced along one side of and above the upper surface of the canal to produce an air curtain completely covering the surface of the canal, and a series of exhaust hood openings on the opposite side of the canal to capture and exhaust the air in the air curtain and a part of the air above the air curtain.

Abstract: A device for removing a cladding material from a bottom portion of a control rod guide tube of a nuclear reactor. A rotor tube is removably mounted in a housing of a control rod drive of the nuclear reactor and has at least its forward end portion hydraulically insertable into the bottom portion of the control rod guide tube through an opening located in a lower portion of the control rod guide tube for inserting the control rod drive. The rotor tube is provided at the forward end portion thereof with a foldable rotary brush and cleaning water supply nozzles. A rotary drive shaft is extending through the rotor tube for rotating the rotary brush. The cladding material deposited on the bottom portion of the control rod guide tube that has become radioactive can be readily and positively removed therefrom with a small volume of water while enabling the risk of exposure to radiation to be minimized at a time the operation of cleaning the bottom portion of the control rod guide tube is performed.

Abstract: There is disclosed in the present application, a decontamination system for reactor vessels. The system is operatable without entry by personnel into the contaminated vessel before the decontamination operation is carried out and comprises an assembly which is introduced into the vertical cylindrical vessel of the typical boiling water reactor through the open top. The assembly includes a circular track which is centered by guideways permanently installed in the reactor vessel and the track guides opposed pairs of nozzles through which water under very high pressure is directed at the wall for progressively cutting and sweeping a tenacious radioactive coating as the nozzles are driven around the track in close proximity to the vessel wall. The whole assembly is hoisted to a level above the top of the vessel by a crane, outboard slides on the assembly brought into engagement with the permanent guideways and the assembly progressively lowered in the vessel as the decontamination operation progresses.

Abstract: Apparatus is disclosed for decontaminating a nuclear reactor pressure vessel. It comprises a buoyant annular frame which descends into the vessel as the water level within it is lowered. Spray nozzles move around the frame on trolleys in a reciprocating fashion and spray water under high pressure on the inner surface of the vessel wall, resulting in automatic washdown of the reactor vessel.

Abstract: In a blow-off device for limiting excess pressure in nuclear power plants, at least one condensation tube disposed so that a lower outlet end thereof is immersed in a volume of cooling water in a condensation chamber having a gas cushion located in a space above the volume of cooling water, and the upper inlet end of the condensation tube extending out of the volume of cooling water and being connectible to a source of condensing steam or a steam-air mixture, the outlet end of the condensation tube being provided with an insert for smoothing the condensation, said insert comprising wall portions forming storage chambers distributed over the length of said tube outlet end and having overflow edges for the cooling water, whereby a spraying action multiplying the heat-transfer surface between the cooling water and a flow of the steam is releasable at said overflow edges when cooling water received in said storage chambers is alternatingly depleted and replenished due to pressure and water-level fluctuations with

Abstract: Apparatus for preventing the diversion of plutonium in nuclear fuel reprocessing plants. The apparatus includes various piping arrangements which prevent plutonium in a liquid state from being drawn out of a nuclear fuel reprocessing cell through conduits which are normally accessible to the operators of the facility.

Abstract: A device having a tubular body of an increased diameter closed at its bottom and connected at its top to the lower end of a vent pipe in such a state that the tubular body is immersed in a water pool. The tubular body is formed in its side wall with a multitude of openings for venting steam therethrough to the water pool to condense the same.

Abstract: A blast head including a plurality of spray nozzles mounted in a chamber for receiving a workpiece. The several spray nozzles concurrently direct a plurality of streams of a pressurized gas and abrasive grit mixture toward a peripheral portion of the workpiece to remove particulates or debris therefrom. An exhaust outlet is formed in the chamber for discharging the particulates and spent grit.

Abstract: Method for removal of radioactive cesium from a hot vapor, such as high temperature steam, including the steps of passing input hot vapor containing radioactive cesium into a bed of silicate glass particles and chemically incorporating radioactive cesium in the silicate glass particles at a temperature of at least about 700.degree. F.

Abstract: A robot arm apparatus is provided for inspecting and/or maintaining an interior of a steam generator which has an outside wall and a port for accessing the interior of the steam generator. The robot arm apparatus includes a flexible movable conduit for conveying inspection and/or maintenance apparatus from outside the steam generator to the interior of the steam generator. The flexible conduit has a terminal working end which is translated into and around the interior of the steam generator. Three motors located outside the steam generator are employed for moving the terminal working end inside the steam generator in "x", "y", and "z" directions, respectively. Commonly conducted inspection and maintenance operations include visual inspection for damaged areas, water jet lancing for cleaning sludge deposits, core boring for obtaining sludge deposits, and scrubbing of internal parts.