EP0628969A1 - Verfahren zur Wiederherstellung eines Kernkraftwerkwärmeaustauschers - Google Patents

Verfahren zur Wiederherstellung eines Kernkraftwerkwärmeaustauschers Download PDF

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Publication number
EP0628969A1
EP0628969A1 EP94401266A EP94401266A EP0628969A1 EP 0628969 A1 EP0628969 A1 EP 0628969A1 EP 94401266 A EP94401266 A EP 94401266A EP 94401266 A EP94401266 A EP 94401266A EP 0628969 A1 EP0628969 A1 EP 0628969A1
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EP
European Patent Office
Prior art keywords
water
water box
heat exchanger
decontamination solution
circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94401266A
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English (en)
French (fr)
Inventor
Martin Bourdelet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Areva NP SAS
Original Assignee
Framatome SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Framatome SA filed Critical Framatome SA
Publication of EP0628969A1 publication Critical patent/EP0628969A1/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
    • F28G9/00—Cleaning by flushing or washing, e.g. with chemical solvents
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/48—Devices for removing water, salt, or sludge from boilers; Arrangements of cleaning apparatus in boilers; Combinations thereof with boilers
    • F22B37/483—Devices for removing water, salt, or sludge from boilers; Arrangements of cleaning apparatus in boilers; Combinations thereof with boilers specially adapted for nuclear steam generators
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof
    • G21F9/002—Decontamination of the surface of objects with chemical or electrochemical processes
    • G21F9/004—Decontamination of the surface of objects with chemical or electrochemical processes of metallic surfaces

Definitions

  • the present invention relates to a method for restoring a heat exchanger of a nuclear power plant and its application to a heat exchanger of the auxiliary cooling circuit of a nuclear reactor that is stopped.
  • the cooling circuit of the shutdown reactor has the function of removing the heat from the primary circuit and the residual power of the core during the cold shutdown of the reactor.
  • this cooling circuit comprises two identical subsystems arranged in parallel, each subsystem comprising a centrifugal pump, a heat exchanger, and a device for controlling the cooling rate.
  • the heat exchanger comprises a water box detachably attached to the rest of the heat exchanger, divided by a wall into two compartments or half water boxes.
  • Each half-water box is connected to the cooling circuit of the shutdown reactor by a pipe provided with an end connected to a member of this cooling circuit, for example to a valve of this circuit, by removable means.
  • the heat exchanger also comprises a bundle of U-shaped tubes forming heat exchange elements having their ends connected respectively to the two half-water boxes.
  • the wall separating the two half-water boxes is subjected to significant stresses which can lead, in the long run, to the deformation of this wall and to the appearance of leaks between the two half -water boxes.
  • the elements of the heat exchanger in which the water from the cooling circuit of the shutdown reactor circulates are contaminated by radioactive radiation which can harm the personnel responsible for maintenance operations.
  • Radioactive contamination is mainly distributed over the internal surfaces of the tube bundle, the water box and the connection conduits of each half-water box. This contamination is due in particular to the presence of a layer of oxides containing radionuclides such as cobalt 60.
  • the cerium solution constitutes an aggressive and strongly oxidizing chemical medium making it possible to erode the oxide layer and the contaminated surface.
  • the cerium is reduced to valence III and then regenerated to valence IV by injecting ozone into the solution.
  • the object of the invention is in particular to replace and decontaminate the used water box of a heat exchanger for the auxiliary cooling circuit of a stopped nuclear reactor, by using a decontamination solution of the aforementioned type and by minimizing the radiation doses to which maintenance personnel are subject as well as the time and cost of carrying out these interventions.
  • the invention also relates to the application of the method as defined above to a heat exchanger of the auxiliary cooling circuit of a shutdown nuclear reactor.
  • FIG. 1 shows a steam generator for the auxiliary cooling circuit of a shutdown nuclear reactor, in particular of a pressurized water or boiling water nuclear reactor, designated by the general reference 1, intended for undergo a maintenance process according to the invention.
  • the heat exchanger 1 comprises a water box 2 divided by a wall 3 into two compartments or half water boxes 2A, 2B, fixed to the rest of the heat exchanger 1 by removable means comprising a flange 4 and studs 5 shown schematically in the figures by dashed lines.
  • Each half-water box 2A, 2B is connected to the auxiliary cooling circuit by a duct 6A, 6B one end of which is secured to the water box and the other end of which is connected to the auxiliary circuit, for example to a valve of this circuit, by means of flanges 7A, 7B removable.
  • the heat exchanger further comprises a bundle 8 of tubes 9 in U, forming exchange elements heat, having their two ends connected respectively to the two half-water boxes 2A, 2B.
  • the ends of the tubes 9 are fixed in a tubular plate 10 covering an open face of the water box.
  • the auxiliary cooling circuit is supplied with primary water from the nuclear reactor, this water being cooled in the heat exchanger 1 by demineralized water circulating in contact with the external surface of the tubes 9 of the bundle 8 and in a circuit usually called "intermediate circuit".
  • the partition wall 3 is deformed under the effect of the thermal stresses to which it is subjected during the operation of the heat exchanger 1, and the internal surfaces of the tubes 9 of the bundle, of the water box 2 and of its conduits. connection 6A, 6B are contaminated by radiation. This justifies maintenance of the heat exchanger to keep it in working condition without excessive contamination.
  • connection conduits 6A, 6B are separated from the auxiliary cooling circuit by dismantling the flange means 7A, 7B.
  • each half-water box 2A, 2B is partitioned in a manner which will be specified below and the water box 2 is reassembled on the heat exchanger as shown in FIG. 2.
  • connection conduits 6A, 6B after separation of the connection conduits 6A, 6B from the auxiliary cooling circuit, the free ends of these conduits can be closed so as to avoid the diffusion of radiation outside these conduits during the disassembly operations , partitioning and reassembly of the water box.
  • each half-water box 2A, 2B is isolated from the tubes 9 of the bundle which are initially connected to it, for example by means of a separation plate 11 interposed between the flange 4 of the water box 2 and the tubular plate 10, and on the other hand so as to form in each half water box 2A, 2B a compartment 12A, 12B, delimited by the internal surface of the half-water box, having a limited volume compared to that of this half-water box.
  • Each compartment 12A, 12B is connected to the connection conduit 6A, 6B of the corresponding half-water box, and each assembly of connection conduit 6A, 6B-compartment 12A, 12B is connected, in a manner known per se, by upstream conduits 14A, 14B and downstream 16A, 16B, upstream branches AT and downstream AL of a decontamination circuit CD in which a predetermined volume of decontamination solution is intended to circulate in a closed loop.
  • This CD circuit will be described in more detail below.
  • the tubes 9 of the bundle are also connected to the upstream AT and downstream branches AL of the CD circuit by means of two upstream and downstream manifolds 18A, 18B fixed against the tube plate 10.
  • the upstream collector 18A is arranged opposite the upstream ends of the tubes 9 and the downstream collector 18B is arranged opposite the downstream ends of these tubes 9.
  • the two collectors 18A, 18B have shapes that are substantially symmetrical with respect to the dividing wall 3 of the two half-water boxes.
  • this collector 18A is partitioned so as to delimit compartments 20 communicating with a group of tubes 9 and connected by via an upstream branched conduit 14C to the upstream branch AT of the CD decontamination circuit.
  • the downstream collector 18B is connected, analogously to the upstream collector 18A, to the downstream branch AL of the decontamination circuit CD via a branched downstream conduit 16C.
  • connection ducts 6A, 6B-compartment 12A, 12B and the bundle 8 of tubes are connected in parallel to the upstream and downstream branches AT, AL of the decontamination circuit CD, each of these elements being able to be isolated from the CD decontamination circuit by valves 22A-22C, 24A-24C.
  • FIG 4 there is shown an installation 25 for the decontamination of contaminated elements of the heat exchanger, comprising the CD circuit.
  • the CD decontamination circuit includes a circulation tank 26 intended to contain the decontamination solution, connected by a conduit 28 to the suction of a circulation pump 30.
  • the pump 30 is connected to a discharge conduit 32 connected via an isolation valve 34 to a conduit forming the upstream branch AT of the CD circuit.
  • the CD circuit also includes filtration means 36 connected, on the one hand to a conduit 38 connected, by means of an isolation valve 39, to a conduit forming the downstream branch AL of the CD circuit, and on the other hand to the circulation tank 26, by a conduit 40.
  • the filtration means 36 comprise two filters 42,44 connected in parallel to the conduits 38 and 40. Each filter 42,44 can be isolated from the CD circuit by two valves 46,48 disposed respectively upstream and downstream of the filter. A valve 50 bypass valve 42, 44 is connected between the conduits 38 and 40.
  • a valve 54 bypassing the receptacle 2 is connected between the pipe 32 for discharging the pump 30 and the pipe 38 for supplying the filters 42, 44.
  • the installation 25 also includes means 56 for ozonation of the decontamination solution.
  • These means 56 comprise an ozonizer 58 connected by a conduit 60 to an injection circuit 62 with a horn 64.
  • the ozonator 58 is connected to a reservoir 66 for supplying oxygen by a conduit 68 provided with a valve 69 with safety valve.
  • the injection circuit 62 comprises an injection pump 70, the suction of which is connected by a conduit 72 to the circulation tank 26 and the discharge of which is connected to the upstream end of the tube 64 by a conduit 74. downstream end of the tube 64 is connected by a conduit 76 to the circulation tank 26.
  • the conduits 72, 76 are respectively provided with valves 72A, 76A for isolating the means 56 for ozonation of the circuit CD for circulation of the solution.
  • FIG. 4 also shows an auxiliary tank 78 connected to the circulation tank 26 by means 80 of content transfer.
  • This tank 78 is intended in particular for the preparation of the decontamination solution and for the intermediate storage of this solution after emptying of the circulation tank 26.
  • the transfer means 80 comprise a conduit 82, connecting the circulation tanks 26 and the auxiliary tanks 78 to one another, provided with a reversible pump 84.
  • Agitation means 86 arranged in the auxiliary tank 78, make it possible in particular to mix the various constituents of the solution during its preparation.
  • auxiliary tank 78 The upper part of the auxiliary tank 78 is connected by a conduit 88 to means 90 for processing and evacuating the gaseous atmosphere contained in the tank above the level of liquid.
  • means 90 comprise a very high efficiency filter 92, of known type, connected in series with an ozone destroyer 94 opening into the open air.
  • the upper part of the circulation tank 26 is connected to the upper part of the auxiliary tank 78 by a conduit 96 provided with a valve 98 with safety valve, allowing the communication of the gaseous atmospheres of the two circulation tanks 26 and auxiliary 78 .
  • the lower part of the auxiliary reservoir 78 is connected to means 100 for draining the solution from the reservoir comprising a conduit 102 provided with a drainage valve 104.
  • a first end of the conduit 102 is connected to the bottom of the reservoir 78 and the second end of the conduit 102 is connected to a collector of liquid effluents, not shown in the figures.
  • the various tanks and filters of the installation 25 are mounted on mobile supports or vehicles, so that they can be moved on the site of the power station in which the heat exchangers are arranged.
  • the various conduits of the installation 25 can advantageously comprise flexible metal pipes.
  • connection duct assembly 6A, 6B-compartment 12A, 12B and in the bundle 8 of tubes a so-called "mild” acid decontamination solution, comprising nitric acid imposing a pH of the solution between 2.5 and 3, and cerium nitrate in a proportion of 8 to 10 g / l.
  • cerium nitrate can be replaced by cerium sulfate.
  • this mild decontamination solution is initially prepared in the auxiliary tank 78, the volume of solution being adapted to the volume of the elements to be decontaminated.
  • the mild decontamination solution is transferred from the auxiliary tank 78 to the circulation tank 26 by means of the transfer pump 84.
  • the circulation pump 30 makes it possible to circulate the solution in the decontamination circuit CD and in the contaminated elements of the heat exchanger 1.
  • the partitioning of the half-water boxes makes it possible, mainly, to maintain an optimal speed of circulation of the decontamination solution in order to avoid the redeposition of the contaminated particles torn from the contaminated surfaces, and secondarily to minimize the volume of solution of decontamination circulating in contact with contaminated internal surfaces of water boxes or the tube bundle.
  • the latter is supplied with ozone using the ozonization means 56 so as to maintain an ozone concentration in the solution of between 2.5 and 25 ppm approximately.
  • the decontamination solution is circulated in the elements of the heat exchanger connected to the CD decontamination circuit for a period which can reach or even exceed 24 to 48 hours.
  • the decontamination solution reacts with the oxide layer covering the internal surface of the elements of the heat exchanger 1 connected to the CD circuit as well as with the surface layer of the metal constituting these elements.
  • the valence II iron of the oxide layer is oxidized to valence III and the valence III chromium of the oxide layer is oxidized to chromium of valence VI according to the chemical reaction below: 6 Ce4+ + Cr2O3 + 11 H2O ⁇ 2 H2CrO4 + 6 Ce3+ + 6 H3O +.
  • the valence III iron and the valence VI chromium are dissolved in the solution.
  • the valence III cerium (Ce3+ ions) is regenerated to valence IV cerium (Ce4+ ions) by ozone according to the chemical reaction below: 6 H3O+ + O3 + 6 Ce3+ ⁇ 6 Ce4+ + 9 H2O.
  • the temperature of the solution is maintained between 20 and 30 ° in order to ensure a sufficient lifetime of the ozone in the solution allowing it to regenerate the cerium to its valence IV.
  • the flow rate of the circulation pump 30 is adapted so that the speed of the decontamination solution in the contaminated elements of the heat exchanger heat 1 is sufficient to prevent the contaminated particles torn from the internal surface of the contaminated elements of the heat exchanger 1 from being redeposited in these elements.
  • the CD decontamination circuit can be provided with means for reversing the direction of circulation of the solution so as to be able to periodically reverse the direction of circulation of this solution in the contaminated elements of the heat exchanger connected to the CD circuit. .
  • the filtration means 36 make it possible to retain at least part of the particles torn from the contaminated elements of the heat exchanger 1.
  • only one filter 42,44 is used at a time.
  • the pressure drop across the operational filter becomes too large, it switches from one filter to another by means of valves 46,48 for isolating the filters. It is also possible, after a certain period of circulation of the solution, to stop the filtration by isolating the filters from the CD decontamination circuit and by opening the bypass valve 50.
  • the particles torn from the contaminated elements can be fixed on resins of known type.
  • the entire volume of solution contained in the CD decontamination circuit by first transferring it to the auxiliary tank 78 by means of the pump 84. Then the used decontamination solution is drained to a collector of liquid effluents, by opening the drainage valve 104 for be treated subsequently according to steps known per se.
  • the residual cerium is reduced to valence III by injection of an oxidizing agent of known type, and at the end of the emptying of the decontamination solution, the decontaminated elements of the heat exchanger with a solution comprising demineralized water.
  • the soft decontamination solution can be circulated separately in each connection duct assembly 6A, 6B-compartment 12A, 12B or in the bundle 8 of tubes by isolating the corresponding elements from the CD circuit or by connecting these elements to the CD circuit , by closing or opening valves 22A-22C, 24A-24C.
  • connection conduits 6A, 6B and the tubes 9 of the bundle 8 can be reused normally after treatment with the mild decontamination solution.
  • the radiation doses to which the maintenance personnel may be subjected are reduced so that interventions on the heat exchanger can be carried out in much less difficult or dangerous conditions than before the decontamination treatment.
  • connection conduits 6A, 6B Following the treatment of the water box 2 and the connection conduits 6A, 6B with the mild decontamination solution, the water half-boxes 2A, 2B are separated from their connection conduit 6A, 6B by cutting these conduits with known means, substantially at their junction with the half-boxes water 2A, 2B.
  • FIGS. 1 and 2 the places of sectioning of the connection conduits 6A, 6B are shown by phantom lines T.
  • each compartment 12A, 12B is connected directly to the upstream conduit 14A, 14B for supplying decontamination solution by connecting this conduit 14A, 14B to the orifice delimited by the base of the connection conduit 6A, 6B remaining on the corresponding half-water box 2A, 2B after cutting off.
  • a so-called "hard” acid decontamination solution is circulated in each compartment 12A, 12B comprising chemical components identical to those of the mild acid decontamination solution but having a pH of between 0.5 and 1.
  • the tube bundle is isolated from the decontamination circuit CD by closing the valves 22C, 24C.
  • the preparation, the circulation in the CD circuit, and the emptying of the hard decontamination solution are done in a similar manner to what has been described previously for the treatment with the soft decontamination solution.
  • the used water box is removed from the heat exchanger 1 and is replaced by a new water box.
  • the new water box provided with nozzles of identical length to that of the sectioned portions of the connection conduits 6A, 6B connected to the used water box, is connected to the auxiliary cooling circuit by the connection conduits 6A, 6B treated with the mild decontamination solution, these conduits 6A, 6B being connected to their corresponding half-water box by welding at the cut edges of the conduits 6A, 6B.
  • This process differs from the process described above in that the partitioning of the water half-boxes 2A, 2B, with a view to circulating therein a gentle decontamination solution, is carried out so as to connect the first conduit of series connection 6A, the compartment 12A of restricted volume of the first half-water box 2A, the compartment 12B of restricted volume of the second half-water box 2B and the second connection conduit 6B.
  • connection conduits 6A, 6B are connected one to the branch AT of the decontamination circuit CD and the other to the downstream branch AL of this circuit.
  • the partitioning of the water box 2 could be eliminated.
  • the method according to this second embodiment also differs from the method according to the first embodiment. realization by the fact that, after cutting off the connection conduits 6A, 6B, the water box 2 of the heat exchanger 1 is dismantled while keeping the partitioning of this water box, and the latter is assembled with another box with water 2 to form a receptacle 106 as shown in FIG. 6.
  • This other water box 2 comes from another heat exchanger identical to the heat exchanger shown in FIG. 1, this other heat exchanger having undergone a maintenance process similar to that undergone by the heat exchanger 1 that we have described.
  • the receptacle 106 is formed by assembling the two water boxes 2 by known means, open face against open face, so as to arrange the median walls of each water box in the extension of one another in order to divide the receptacle 106 in two partitioned compartments 106A, 106B.
  • each compartment 106A, 106B of the receptacle 106 is connected to the upstream AT and downstream AL branches of the decontamination circuit CD by upstream conduits 108A, 110A and downstream 108B, 110B.
  • conduits 108A, 108B, 110A, 110B are connected by known means, to the orifices delimited by the base of the connection conduits 6A, 6B remaining on the water boxes after cutting off the latter.
  • the decontamination of the beam 8 is optional.
  • the method according to the invention can be carried out on central heat exchangers nuclear similar to that described with reference to Figure 1 but intended to be connected to a circuit other than the auxiliary cooling circuit of the nuclear reactor stopped.
  • the invention has many advantages.
  • Treatment with the mild decontamination solution of the contaminated elements of the heat exchanger reduces their contamination while retaining their reliability.
  • the pipes connecting the water box to the water circuit to be cooled as well as the tube bundle can be reused.
  • the treatment of the water box with the hard decontamination solution makes it possible to lower the radiation emitted by this water box below a sufficient threshold to be able to allow the segmentation of this water box and the recycling of the material which constitutes it. .
  • the water box being reassembled after partitioning on the heat exchanger, the emission of radiation is avoided during the treatment of this water box with the decontamination solution.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Thermal Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Cleaning In General (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP94401266A 1993-06-08 1994-06-07 Verfahren zur Wiederherstellung eines Kernkraftwerkwärmeaustauschers Withdrawn EP0628969A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9306854 1993-06-08
FR9306854A FR2706217A1 (fr) 1993-06-08 1993-06-08 Procédé de remise en état d'un échangeur de chaleur de centrale nucléaire, notamment d'un échangeur de chaleur de circuit auxiliaire de refroidissement d'un réacteur nucléaire à l'arrêt.

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EP0628969A1 true EP0628969A1 (de) 1994-12-14

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EP94401266A Withdrawn EP0628969A1 (de) 1993-06-08 1994-06-07 Verfahren zur Wiederherstellung eines Kernkraftwerkwärmeaustauschers

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999043006A1 (fr) * 1998-02-20 1999-08-26 Centre D'etudes De L'energie Nucleaire Procede et installation de decontamination de surfaces metalliques
EP2724792A1 (de) * 2012-10-29 2014-04-30 Hitachi Ltd. Verfahren zur Reinigung von Rohrleitungen und Reinigungssystem für Rohrleitungen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0134664A1 (de) * 1983-07-12 1985-03-20 Westinghouse Electric Corporation Ozon-Oxidation von Ablagerungen in Kühlanlagen von Nuklearreaktoren
WO1985004279A1 (en) * 1984-03-09 1985-09-26 Studsvik Energiteknik Ab Decontamination of pressurized water reactors
EP0164937A1 (de) * 1984-05-29 1985-12-18 Westinghouse Electric Corporation Verfahren zur Dekontamination von Metalloberflächen
WO1990001774A1 (en) * 1988-08-11 1990-02-22 Studsvik Ab Decontamination method
EP0555127A1 (de) * 1992-02-03 1993-08-11 Framatome Verfahren und Einrichtung zur Dekontaminierung eines gebrauchten nuklearen Dampferzeugers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0134664A1 (de) * 1983-07-12 1985-03-20 Westinghouse Electric Corporation Ozon-Oxidation von Ablagerungen in Kühlanlagen von Nuklearreaktoren
WO1985004279A1 (en) * 1984-03-09 1985-09-26 Studsvik Energiteknik Ab Decontamination of pressurized water reactors
EP0164937A1 (de) * 1984-05-29 1985-12-18 Westinghouse Electric Corporation Verfahren zur Dekontamination von Metalloberflächen
WO1990001774A1 (en) * 1988-08-11 1990-02-22 Studsvik Ab Decontamination method
EP0555127A1 (de) * 1992-02-03 1993-08-11 Framatome Verfahren und Einrichtung zur Dekontaminierung eines gebrauchten nuklearen Dampferzeugers

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999043006A1 (fr) * 1998-02-20 1999-08-26 Centre D'etudes De L'energie Nucleaire Procede et installation de decontamination de surfaces metalliques
BE1011754A3 (fr) * 1998-02-20 1999-12-07 En Nucleaire Etabilissement D Procede et installation de decontamination de surfaces metalliques.
EP2724792A1 (de) * 2012-10-29 2014-04-30 Hitachi Ltd. Verfahren zur Reinigung von Rohrleitungen und Reinigungssystem für Rohrleitungen
US20150298179A1 (en) * 2012-10-29 2015-10-22 Hitachi Ltd. Method for cleaning piping and cleaning system for piping
US9744569B2 (en) * 2012-10-29 2017-08-29 Hitachi, Ltd. Method for cleaning piping and cleaning system for piping

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Publication number Publication date
FR2706217A1 (fr) 1994-12-16

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