EP0507641A1 - Process and equipment for working with a laser in a contaminated area of a nuclear plant - Google Patents

Process and equipment for working with a laser in a contaminated area of a nuclear plant Download PDF

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Publication number
EP0507641A1
EP0507641A1 EP92400622A EP92400622A EP0507641A1 EP 0507641 A1 EP0507641 A1 EP 0507641A1 EP 92400622 A EP92400622 A EP 92400622A EP 92400622 A EP92400622 A EP 92400622A EP 0507641 A1 EP0507641 A1 EP 0507641A1
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EP
European Patent Office
Prior art keywords
laser
amplifier
laser beam
contaminated area
amplified
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Granted
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EP92400622A
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German (de)
French (fr)
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EP0507641B1 (en
Inventor
Jean-Pierre Cartry
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Areva NP SAS
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Framatome SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
    • B08B7/0035—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by radiant energy, e.g. UV, laser, light beam or the like
    • B08B7/0042—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by radiant energy, e.g. UV, laser, light beam or the like by laser
    • 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
    • G21F9/28—Treating solids
    • G21F9/30—Processing
    • 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
    • F22B37/002—Component parts or details of steam boilers specially adapted for nuclear steam generators, e.g. maintenance, repairing or inspecting equipment not otherwise provided for
    • F22B37/003—Maintenance, repairing or inspecting equipment positioned in or via the headers
    • 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
    • G21F9/005—Decontamination of the surface of objects by ablation

Definitions

  • the present invention relates to a method and an installation for laser work on a surface contained in a contaminated area of a nuclear installation.
  • the invention applies in particular to the decontamination by laser beam, in an aqueous or gaseous medium, of surfaces having received a deposit of radioactive materials such as activated metal oxides, in order to reduce the level of radiation and thus allow the access or approach of response personnel.
  • the primary circuit of pressurized water nuclear power plants is concerned with this invention and more particularly the water box of the steam generators and the primary pipes.
  • Decontamination may be necessary during a check or repair to be carried out in the contaminated part of the plant, when replacing equipment such as a steam generator, and also when dismantling this plant.
  • the object of the invention is to make it possible to work efficiently by means of a laser in a contaminated area.
  • the method according to the invention is characterized in that a pulsed laser beam is emitted from the contaminated area, this beam is transported to a location close to said surface, and, at this location, it is amplified the beam and the amplified beam is sent to said surface, possibly via a deflection mirror.
  • FIG. 1 there is shown in Figure 1, in axial section, one 1 of the two compartments of the water box 2 of a pressurized water nuclear reactor steam generator.
  • This compartment 1 is delimited upwards by the tube plate 3, on one side by the vertical middle partition 4 of the water box, and on the other side and downwards by the hemispherical bottom 5 of the water box , which is crossed by a manhole 6.
  • a equipment 7 adapted to allow the decontamination by laser beam of the surfaces which delimit compartment 1.
  • This equipment comprises an external apparatus 8 arranged outside the water box, in an appropriate room protected from radiation, and an internal apparatus 9 arranged inside compartment 1 and which can be introduced therein through the manhole.
  • the apparatus 8 comprises a control console 10, a generator of electrical energy and fluids 11, a pulsed laser beam generator 12, constituted by an oscillator possibly followed by a preamplifier, and a suction pump 13 at the inlet which is provided with a filter 14.
  • the apparatus 9 comprises a laser beam amplifier 15 and a confinement enclosure 16 carried by a support 17.
  • the input of the amplifier 15 is connected to the output of the generator 12 by an optical fiber 18 of multimode type having a length at least about 15 m.
  • the enclosure 16 is connected on the one hand, via a line 19, to a source of protective (neutral or reducing) or active gas contained in the generator 11, and on the other hand, via a line 20, to the filter 14 and at the pump 13.
  • the support 17 constitutes the end of an articulated robot, shown diagrammatically at 21, remotely controlled from the console 10 and making it possible to arrange the apparatus 9 facing any region of the surfaces 3, 4, 5 to decontaminate and in the vicinity thereof.
  • the apparatus 9 is shown in more detail in Figure 2.
  • the amplifier 15 is housed in a housing 22 fixed to the support 17 and provided with supply lines 23 and electrical supply 24 and 25 for cooling water discharge. Lines 23 to 25 are connected via a line 26 ( Figure 1) to the generator 11.
  • An inlet face of the housing 12 is pierced with an orifice in which the distal end of the optical fiber 18 is fixed, and an inlet optic 27 makes it possible to introduce at the input of the amplifier 15 a parallel beam of diameter equal to that of the bar of the amplifier.
  • the support 17 carries a frame 30 in which several columns 31 parallel to the axis X-X of the amplifier 15, biased by springs 32 in the opposite direction to this amplifier, are mounted sliding.
  • the enclosure 16, which has a cup shape, has a bottom 33 perpendicular to the axis XX which is fixed to the distal end of the balusters 31, and a side wall 34 whose free edge is provided with rollers 35.
  • the bottom 33 has an orifice 36 of axis XX whose diameter is slightly greater than that of the amplified beam 37.
  • the laser generator 12 is of a type allowing the transport of the beam by optical fiber. It can in particular be of the Nd-YAG type (wavelength 1.06 ⁇ m), of the sapphire type (wavelength centered on 0.78 ⁇ m) or of the excimer type (wavelength 0.3 ⁇ m) . It emits pulses with a duration of 10 to 30 ns.
  • This generator 12 and the amplifier 15 are adjusted to provide an amplified beam 37 whose pulses have an energy of 0.3 to 5 joules or more and an energy density (or fluence) of 1 to 15 J / cm 2 .
  • rollers 35 are applied, with a force determined by the springs 32, to the surface to be decontaminated, which is the partition 4 in the example shown.
  • a protective or active gas scans the enclosure 16, and the pulsed beam emitted by the generator 12, transported by the optical fiber 18 and amplified at 15, is sent directly, in the form of the parallel beam 37, to the surface to be treated, perpendicular to it. All the surfaces to be decontaminated are scanned in this way by moving the support 17 by means of the robot 21.
  • the above-mentioned energy density is chosen so as to allow thermal penetration corresponding to the thickness, or part of the thickness, of the layer of radioactive oxide to be eliminated, each pulse creating a shock wave on this layer.
  • the use of a neutral or sweeping reduction gas reduces the oxidation of the pickled surface, while the use of an active gas, in particular oxygen, makes it possible to increase the thickness of the oxide layer. interested in laser pulses.
  • the choice of sweep gas will therefore be established according to the specific conditions of each application.
  • the use of a multimode optical fiber for the transport of the unamplified laser beam provides a considerable advantage linked to the energy distribution in the beam leaving said fiber, and therefore at the level of the beam impact spot. on the wall. Indeed, in this case, the energy distribution is substantially constant over the entire surface of the spot; it is in the form of a slot instead of having a distribution comprising a central peak as is the case with transmission of the beam by air.
  • the fiber must be long enough for the energy homogenization to be correct, for example at least about 15 m. With a shorter optical fiber, it would be appropriate in certain cases to use in the generator 12 a so-called "Gaussian" mirror, known per se, providing a homogeneous, niche distribution of energy.
  • the apparatus 9A shown in Figure 3 differs from that of Figure 2 in that the support 17 is arranged so that the axis X-X of the amplifier 15 is parallel to the surface to be treated.
  • the posts 31 are perpendicular to this axis X-X, and a deflection mirror 38 inclined at 45 ° is fixed opposite the orifice 36 of the enclosure 16.
  • This variant is particularly applicable to laser work in reduced spaces, for example to decontaminate the wall of primary pipes.
  • the variant of Figure 3 can be modified as follows: the 16-column 31-mirror enclosure assembly 38 is connected to the support 17 by means of another support mounted mobile on the latter, in translation and / or in rotation about the axis of the amplifier 15. It is thus possible, for each position of the amplifier , effectively sweep a relatively large region to be treated, regardless of the shape of this region.
  • Figure 4 illustrates means other than suction means for capturing the oxide particles detached from the surface by the impact of the laser beam. It is in this case an electrode 39 held parallel to the surface to be treated by spacers not shown and pierced with an orifice 40 allowing the passage of the laser beam 37. This electrode is carried, thanks to a power supply 41 , at a high potential with respect to the treated surface, so that the detached oxide particles, ionized by the laser beam, are attracted to the electrode 39.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Optics & Photonics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Laser Beam Processing (AREA)
  • Cleaning In General (AREA)
  • Lasers (AREA)

Abstract

According to this process a pulsed laser beam is emitted out of the contaminated area (at 12), this beam is transported as far as a location close to the said surface and, at this location, the beam is amplified (at 15) and the amplified beam is directed onto the said surface. Application to the decontamination of the primary circuit of pressurised-water nuclear reactors. <IMAGE>

Description

La présente invention est relative à un procédé et une installation de travail au laser sur une surface contenue dans une zone contaminée d'une installation nucléaire.The present invention relates to a method and an installation for laser work on a surface contained in a contaminated area of a nuclear installation.

L'invention s'applique notamment à la décontamination par faisceau laser, en milieu aqueux ou gazeux, de surfaces ayant reçu un dépôt de matières radioactives telles que des oxydes de métaux activés, afin de réduire le niveau de radiations et de permettre ainsi l'accès ou l'approche du personnel d'intervention.The invention applies in particular to the decontamination by laser beam, in an aqueous or gaseous medium, of surfaces having received a deposit of radioactive materials such as activated metal oxides, in order to reduce the level of radiation and thus allow the access or approach of response personnel.

Le circuit primaire des centrales nucléaires à eau pressurisée est concerné par cette invention et plus particulièrement la boîte à eau des générateurs de vapeur et les tuyauteries primaires.The primary circuit of pressurized water nuclear power plants is concerned with this invention and more particularly the water box of the steam generators and the primary pipes.

La décontamination peut être nécessaire lors d'une vérification ou d'une réparation à effectuer dans la partie contaminée de la centrale, lors du remplacement d'un équipement tel qu'un générateur de vapeur, et également lors du démantèlement de cette centrale.Decontamination may be necessary during a check or repair to be carried out in the contaminated part of the plant, when replacing equipment such as a steam generator, and also when dismantling this plant.

On connait plusieurs procédés de décontamination :

  • la projection de particules abrasives pour éliminer par abrasion la pellicule d'oxyde radioactive, ou la dissolution chimique de cette pellicule, qui ont pour inconvénient de produire des quantités importantes d'effluents coûteux à traiter;
  • la décontamination par faisceau laser. Dans un procédé connu de ce type, décrit dans le FR-A-2 525 380, un faisceau laser est émis à l'entrée de la boîte à eau et renvoyé sur la paroi intérieure de celle-ci par des miroirs orientables fixés à la plaque tubulaire. Ce procédé, de par sa conception même, ne permet pas, même avec des impulsions laser à forte densité d'énergie, de traiter de façon uniforme toutes les surfaces à décontaminer.
Several decontamination processes are known:
  • the projection of abrasive particles to eliminate by abrasion the film of radioactive oxide, or the chemical dissolution of this film, which have the disadvantage of producing large quantities of effluents which are expensive to treat;
  • laser beam decontamination. In a known method of this type, described in FR-A-2 525 380, a laser beam is emitted at the entrance to the water box and returned to the inside wall of the latter by orientable mirrors fixed to the tubular plate. This process, by its very design, does not allow, even with high energy density laser pulses, to uniformly treat all surfaces to be decontaminated.

L'invention a pour but de permettre de travailler de façon efficace au moyen d'un laser dans une zone contaminée.The object of the invention is to make it possible to work efficiently by means of a laser in a contaminated area.

A cet effet, le procédé suivant l'invention est caractérisé en ce qu'on émet hors de la zone contaminée un faisceau laser pulsé, on transporte ce faisceau jusqu'à un emplacement voisin de ladite surface, et, à cet emplacement, on amplifie le faisceau et on envoie le faisceau amplifié sur ladite surface, éventuellement par l'intermédiaire d'un miroir de renvoi.To this end, the method according to the invention is characterized in that a pulsed laser beam is emitted from the contaminated area, this beam is transported to a location close to said surface, and, at this location, it is amplified the beam and the amplified beam is sent to said surface, possibly via a deflection mirror.

Suivant d'autres caractéristiques :

  • on effectue le transport au moyen d'une fibre optique;
  • on envoie un gaz protecteur ou actif dans la région de travail pendant le travail au laser;
  • on confine la région de travail et, pendant le travail au laser, on aspire le gaz contenu dans la région confinée;
  • on fait passer le faisceau amplifié à travers un orifice d'une électrode parallèle à ladite surface, et on crée un champ électrique entre cette électrode et ladite surface pendant le travail au laser;
  • pour la décontamination de ladite surface, on utilise un faisceau laser qui, après amplification, possède des impulsions ayant une énergie de 0,3 à 5 joules, ou plus, une durée de 10 à 30 ns, et une densité d'énergie de 1 à 15 J/cm2.
According to other characteristics:
  • the transport is carried out by means of an optical fiber;
  • a protective or active gas is sent into the working region during the laser work;
  • the working region is confined and, during laser work, the gas contained in the confined region is sucked;
  • passing the amplified beam through an orifice of an electrode parallel to said surface, and creating an electric field between this electrode and said surface during laser work;
  • for the decontamination of said surface, a laser beam is used which, after amplification, has pulses having an energy of 0.3 to 5 joules, or more, a duration of 10 to 30 ns, and an energy density of 1 at 15 J / cm2.

L'invention a également pour objet un équipement destiné à la mise en oeuvre d'un tel procédé. Cet équipement est caractérisé en ce qu'il comprend :

  • un générateur de faisceau laser pulsé disposé en dehors de la zone contaminée;
  • un amplificateur de faisceau laser;
  • des moyens de transport du faisceau laser pulsé jusqu'à l'entrée de cet amplificateur; et
  • des moyens pour déplacer l'amplificateur en regard de ladite surface et au voisinage de celle-ci.
The invention also relates to equipment intended for the implementation of such a method. This equipment is characterized in that it includes:
  • a pulsed laser beam generator disposed outside the contaminated area;
  • a laser beam amplifier;
  • means for transporting the pulsed laser beam to the input of this amplifier; and
  • means for moving the amplifier opposite said surface and in the vicinity thereof.

Suivant d'autres caractéristiques :

  • le générateur est du type Nd-YAG, saphir ou excimère, éventuellement muni d'un miroir gaussien de renvoi, et lesdits moyens de transport comprennent une fibre optique;
  • la fibre optique a une longueur d'au moins 15 m environ;
  • l'équipement comprend un miroir de renvoi monté en sortie de l'amplificateur et éventuellement mobile par rapport à celui-ci.
According to other characteristics:
  • the generator is of the Nd-YAG type, sapphire or excimer, optionally provided with a Gaussian reflecting mirror, and said means of transport comprise an optical fiber;
  • the optical fiber has a length of at least about 15 m;
  • the equipment includes a deflection mirror mounted at the output of the amplifier and possibly movable relative to the latter.

Des exemples de mise en oeuvre de l'invention vont maintenant être décrits en regard des dessins annexés sur lesquels :

  • la Figure 1 représente schématiquement un équipement de décontamination au laser conforme à l'invention;
  • la Figure 2 représente à plus grande échelle un détail de cet équipement;
  • la Figure 3 est une vue analogue à la Figure 2 d'une variante; et
  • la Figure 4 est une vue partielle d'une autre variante.
Examples of implementation of the invention will now be described with reference to the accompanying drawings in which:
  • Figure 1 schematically shows a laser decontamination equipment according to the invention;
  • Figure 2 shows on a larger scale a detail of this equipment;
  • Figure 3 is a view similar to Figure 2 of a variant; and
  • Figure 4 is a partial view of another variant.

On a représenté à la Figure 1, en coupe axiale, l'un 1 des deux compartiments de la boîte à eau 2 d'un générateur de vapeur de réacteur nucléaire à eau pressurisée. Ce compartiment 1 est délimité vers le haut par la plaque tubulaire 3, d'un côté par la cloison verticale médiane 4 de la boîte à eau, et de l'autre côté et vers le bas par le fond hémisphérique 5 de la boîte à eau, lequel est traversé par un trou d'homme 6.There is shown in Figure 1, in axial section, one 1 of the two compartments of the water box 2 of a pressurized water nuclear reactor steam generator. This compartment 1 is delimited upwards by the tube plate 3, on one side by the vertical middle partition 4 of the water box, and on the other side and downwards by the hemispherical bottom 5 of the water box , which is crossed by a manhole 6.

On a également représenté sur la Figure 1 un équipement 7 adapté pour permettre la décontamination par faisceau laser des surfaces qui délimitent le compartiment 1. Cet équipement comprend un appareillage externe 8 disposé à l'extérieur de la boîte à eau, dans un local approprié protégé des radiations, et un appareillage interne 9 disposé à l'intérieur du compartiment 1 et pouvant être introduit dans celui-ci à travers le trou d'homme.Also shown in Figure 1 is a equipment 7 adapted to allow the decontamination by laser beam of the surfaces which delimit compartment 1. This equipment comprises an external apparatus 8 arranged outside the water box, in an appropriate room protected from radiation, and an internal apparatus 9 arranged inside compartment 1 and which can be introduced therein through the manhole.

L'appareillage 8 comprend un pupitre de commande 10, un générateur d'énergie électrique et de fluides 11, un générateur de faisceau laser pulsé 12, constitué par un oscillateur éventuellement suivi d'un préamplificateur, et une pompe aspirante 13 à l'entrée de laquelle est prévu un filtre 14.The apparatus 8 comprises a control console 10, a generator of electrical energy and fluids 11, a pulsed laser beam generator 12, constituted by an oscillator possibly followed by a preamplifier, and a suction pump 13 at the inlet which is provided with a filter 14.

L'appareillage 9 comprend un amplificateur de faisceau laser 15 et une enceinte de confinement 16 portés par un support 17. L'entrée de l'amplificateur 15 est reliée à la sortie du générateur 12 par une fibre optique 18 de type multimode ayant une longueur d'au moins 15 m environ. L'enceinte 16 est reliée d'une part, via une conduite 19, à une source de gaz protecteur (neutre ou réducteur) ou actif contenue dans le générateur 11, et d'autre part, via une conduite 20, au filtre 14 et à la pompe 13. Le support 17 constitue l'extrémité d'un robot articulé, schématisé en 21, télécommandé depuis le pupitre 10 et permettant de disposer l'appareillage 9 en regard de n'importe quelle région des surfaces 3, 4, 5 à décontaminer et au voisinage de celle-ci.The apparatus 9 comprises a laser beam amplifier 15 and a confinement enclosure 16 carried by a support 17. The input of the amplifier 15 is connected to the output of the generator 12 by an optical fiber 18 of multimode type having a length at least about 15 m. The enclosure 16 is connected on the one hand, via a line 19, to a source of protective (neutral or reducing) or active gas contained in the generator 11, and on the other hand, via a line 20, to the filter 14 and at the pump 13. The support 17 constitutes the end of an articulated robot, shown diagrammatically at 21, remotely controlled from the console 10 and making it possible to arrange the apparatus 9 facing any region of the surfaces 3, 4, 5 to decontaminate and in the vicinity thereof.

L'appareillage 9 est représenté plus en détail sur la Figure 2. Comme on le voit sur cette figure, l'amplificateur 15 est logé dans un boîtier 22 fixé au support 17 et pourvu de conduites 23 d'alimentation électrique et 24 d'arrivée et 25 d'évacuation d'eau de refroidissement. Les conduites 23 à 25 sont reliées via une ligne 26 (Figure 1) au générateur 11. Une face d'entrée du boîtier 12 est percée d'un orifice dans lequel est fixée l'extrémité distale de la fibre optique 18, et une optique d'entrée 27 permet d'introduire à l'entrée de l'amplificateur 15 un faisceau parallèle de diamètre égal à celui du barreau de l'amplificateur. Ce faisceau ressort amplifié à l'autre extrémité de l'amplificateur 15, et son diamètre est réduit par une optique de sortie 28, puis sort du boîtier 22 sous forme d'un faisceau pulsé parallèle à travers un orifice de sortie 29.The apparatus 9 is shown in more detail in Figure 2. As can be seen in this figure, the amplifier 15 is housed in a housing 22 fixed to the support 17 and provided with supply lines 23 and electrical supply 24 and 25 for cooling water discharge. Lines 23 to 25 are connected via a line 26 (Figure 1) to the generator 11. An inlet face of the housing 12 is pierced with an orifice in which the distal end of the optical fiber 18 is fixed, and an inlet optic 27 makes it possible to introduce at the input of the amplifier 15 a parallel beam of diameter equal to that of the bar of the amplifier. This amplified spring beam at the other end of the amplifier 15, and its diameter is reduced by an exit optic 28, then leaves the case 22 in the form of a parallel pulsed beam through an exit orifice 29.

A son extrémité distale, le support 17 porte un cadre 30 dans lequel plusieurs colonnettes 31 parallèles à l'axe X-X de l'amplificateur 15, sollicitées par des ressorts 32 dans le sens opposé à cet amplificateur, sont montées coulissantes. L'enceinte 16, qui a une forme de coupelle, présente un fond 33 perpendiculaire à l'axe X-X qui est fixé à l'extrémité distale des colonnettes 31, et une paroi latérale 34 dont le bord libre est muni de roulettes 35. Le fond 33 comporte un orifice 36 d'axe X-X dont le diamètre est légèrement supérieur à celui du faisceau amplifié 37.At its distal end, the support 17 carries a frame 30 in which several columns 31 parallel to the axis X-X of the amplifier 15, biased by springs 32 in the opposite direction to this amplifier, are mounted sliding. The enclosure 16, which has a cup shape, has a bottom 33 perpendicular to the axis XX which is fixed to the distal end of the balusters 31, and a side wall 34 whose free edge is provided with rollers 35. The bottom 33 has an orifice 36 of axis XX whose diameter is slightly greater than that of the amplified beam 37.

Le générateur laser 12 est d'un type permettant le transport du faisceau par fibre optique. Il peut être en particulier du type Nd-YAG (longueur d'onde 1,06 µm), du type saphir (longueur d'onde centrée sur 0,78 µm) ou du type excimère (longueur d'onde 0,3 µm). Il émet des impulsions ayant une durée de 10 à 30 ns. Ce générateur 12 et l'amplificateur 15 sont réglés pour fournir un faisceau amplifié 37 dont les impulsions ont une énergie de 0,3 à 5 joules ou plus et une densité d'énergie (ou fluence) de 1 à 15 J/cm2.The laser generator 12 is of a type allowing the transport of the beam by optical fiber. It can in particular be of the Nd-YAG type (wavelength 1.06 μm), of the sapphire type (wavelength centered on 0.78 μm) or of the excimer type (wavelength 0.3 μm) . It emits pulses with a duration of 10 to 30 ns. This generator 12 and the amplifier 15 are adjusted to provide an amplified beam 37 whose pulses have an energy of 0.3 to 5 joules or more and an energy density (or fluence) of 1 to 15 J / cm 2 .

En fonctionnement, les roulettes 35 sont appliquées, avec une force déterminée par les ressorts 32, sur la surface à décontaminer, qui est la cloison 4 dans l'exemple représenté. Un gaz protecteur ou actif balaye l'enceinte 16, et le faisceau pulsé émis par le générateur 12, transporté par la fibre optique 18 et amplifié en 15, est envoyé directement, sous la forme du faisceau parallèle 37, sur la surface à traiter, perpendiculairement à celle-ci. On balaie toutes les surfaces à décontaminer de cette manière en déplaçant le support 17 au moyen du robot 21.In operation, the rollers 35 are applied, with a force determined by the springs 32, to the surface to be decontaminated, which is the partition 4 in the example shown. A protective or active gas scans the enclosure 16, and the pulsed beam emitted by the generator 12, transported by the optical fiber 18 and amplified at 15, is sent directly, in the form of the parallel beam 37, to the surface to be treated, perpendicular to it. All the surfaces to be decontaminated are scanned in this way by moving the support 17 by means of the robot 21.

La densité d'énergie précitée est choisie de manière à permettre une pénétration thermique correspondant à l'épaisseur, ou à une partie de l'épaisseur, de la couche d'oxyde radioactive à éliminer, chaque impulsion créant une onde de choc sur cette couche. L'utilisation d'un gaz neutre ou réducteur de balayage réduit l'oxydation de la surface décapée, tandis que l'utilisation d'un gaz actif, notamment d'oxygène, permet d'augmenter l'épaisseur de la couche d'oxyde intéressée par les impulsions laser. Le choix du gaz de balayage sera donc établi en fonction des conditions particulières de chaque application.The above-mentioned energy density is chosen so as to allow thermal penetration corresponding to the thickness, or part of the thickness, of the layer of radioactive oxide to be eliminated, each pulse creating a shock wave on this layer. . The use of a neutral or sweeping reduction gas reduces the oxidation of the pickled surface, while the use of an active gas, in particular oxygen, makes it possible to increase the thickness of the oxide layer. interested in laser pulses. The choice of sweep gas will therefore be established according to the specific conditions of each application.

L'utilisation d'une fibre optique multimode pour le transport du faisceau laser non amplifié, procure un avantage considérable lié à la répartition d'énergie dans le faisceau en sortie de ladite fibre, et donc au niveau de la tache d'impact du faisceau sur la paroi. En effet, dans ce cas, la répartition d'énergie est sensiblement constante sur toute la surface de la tache; elle est en forme de créneau au lieu d'avoir une répartition comportant un pic central comme c'est le cas avec une transmission du faisceau par voie aérienne. Il faut cependant que la fibre soit suffisamment longue pour que l'homogénéisation de l'énergie soit correcte, par exemple au moins 15 m environ. Avec une fibre optique plus courte, il conviendrait dans certains cas d'utiliser dans le générateur 12 un miroir dit "gaussien", connu en soi, fournissant une répartition homogène, en créneau, de l'énergie.The use of a multimode optical fiber for the transport of the unamplified laser beam, provides a considerable advantage linked to the energy distribution in the beam leaving said fiber, and therefore at the level of the beam impact spot. on the wall. Indeed, in this case, the energy distribution is substantially constant over the entire surface of the spot; it is in the form of a slot instead of having a distribution comprising a central peak as is the case with transmission of the beam by air. However, the fiber must be long enough for the energy homogenization to be correct, for example at least about 15 m. With a shorter optical fiber, it would be appropriate in certain cases to use in the generator 12 a so-called "Gaussian" mirror, known per se, providing a homogeneous, niche distribution of energy.

Comme on le comprend, une répartition en créneau de l'énergie permet de travailler sans perte d'efficacité avec des puissances laser réduites, ce qui est avantageux.As can be understood, a distribution of energy by niche makes it possible to work without loss of efficiency with reduced laser powers, which is advantageous.

L'utilisation d'un amplificateur 15 à proximité de la surface à décontaminer présente de nombreux avantages :

  • le générateur laser 12 est disposé en dehors de la zone contaminée;
  • le faisceau laser peut être transporté par fibre optique jusqu'au voisinage de la surface à traiter, avec les avantages précités, ce qui ne serait pas le cas si toute l'énergie du faisceau 37 était fournie par le générateur 12, à cause des possibilités limitées de transport de puissance laser des fibres optiques;
  • le faisceau 37 étant un faisceau parallèle qui arrive perpendiculairement sur la surface à traiter, la distance entre cette surface et l'orifice de sortie de faisceau 29 de l'amplificateur n'est pas critique, et il n'est pas nécessaire de la maintenir constante.
The use of an amplifier 15 near the surface to be decontaminated has many advantages:
  • the laser generator 12 is disposed outside the contaminated area;
  • the laser beam can be transported by optical fiber to the vicinity of the surface to be treated, with the aforementioned advantages, which would not be the case if all the energy of the beam 37 was supplied by the generator 12, because of the possibilities limited laser power transport of optical fibers;
  • the beam 37 being a parallel beam which arrives perpendicularly on the surface to be treated, the distance between this surface and the beam exit orifice 29 of the amplifier is not critical, and it is not necessary to maintain it constant.

L'appareillage 9A représenté sur la Figure 3 diffère de celui de la Figure 2 par le fait que le support 17 est agencé de façon que l'axe X-X de l'amplificateur 15 soit parallèle à la surface à traiter. Les colonnettes 31 sont perpendiculaires à cet axe X-X, et un miroir de renvoi 38 incliné à 45° est fixé en regard de l'orifice 36 de l'enceinte 16. Le fonctionnement de cette variante est le même que celui décrit plus haut. Cette variante s'applique notamment au travail au laser dans des espaces réduits, par exemple pour décontaminer la paroi des tuyauteries primaires.The apparatus 9A shown in Figure 3 differs from that of Figure 2 in that the support 17 is arranged so that the axis X-X of the amplifier 15 is parallel to the surface to be treated. The posts 31 are perpendicular to this axis X-X, and a deflection mirror 38 inclined at 45 ° is fixed opposite the orifice 36 of the enclosure 16. The operation of this variant is the same as that described above. This variant is particularly applicable to laser work in reduced spaces, for example to decontaminate the wall of primary pipes.

La variante de la Figure 3 peut être modifiée comme suit : l'ensemble enceinte 16-colonnettes 31-miroir 38 est relié au support 17 par l'intermédiaire d'un autre support monté mobile sur ce dernier, en translation et/ou en rotation autour de l'axe de l'amplificateur 15. On peut ainsi, pour chaque position de l'amplificateur, balayer efficacement une région relativement étendue à traiter, quelle que soit la forme de cette région.The variant of Figure 3 can be modified as follows: the 16-column 31-mirror enclosure assembly 38 is connected to the support 17 by means of another support mounted mobile on the latter, in translation and / or in rotation about the axis of the amplifier 15. It is thus possible, for each position of the amplifier , effectively sweep a relatively large region to be treated, regardless of the shape of this region.

La Figure 4 illustre des moyens autres que des moyens d'aspiration pour capturer les particules d'oxyde détachées de la surface par l'impact du faisceau laser. Il s'agit dans ce cas d'une électrode 39 maintenue parallèle à la surface à traiter par des entretoises non représentées et percée d'un orifice 40 permettant le passage du faisceau laser 37. Cette électrode est portée, grâce à une alimentation électrique 41, à un potentiel élevé par rapport à la surface traitée, de sorte que les particules d'oxyde détachées, ionisées par le faisceau laser, sont attirées sur l'électrode 39.Figure 4 illustrates means other than suction means for capturing the oxide particles detached from the surface by the impact of the laser beam. It is in this case an electrode 39 held parallel to the surface to be treated by spacers not shown and pierced with an orifice 40 allowing the passage of the laser beam 37. This electrode is carried, thanks to a power supply 41 , at a high potential with respect to the treated surface, so that the detached oxide particles, ionized by the laser beam, are attracted to the electrode 39.

Claims (12)

1 - Procédé de travail au laser sur une surface (3, 4, 5) contenue dans une zone contaminée (2) d'une installation nucléaire, caractérisé en ce qu'on émet hors de la zone contaminée (en 12) un faisceau laser pulsé, on transporte ce faisceau jusqu'à un emplacement voisin de ladite surface, et, à cet emplacement, on amplifie (en 15) le faisceau et on envoie le faisceau amplifié sur ladite surface, éventuellement par l'intermédiaire d'un miroir de renvoi. 1 - Method of working with a laser on a surface (3, 4, 5) contained in a contaminated area (2) of a nuclear installation, characterized in that a laser beam is emitted outside the contaminated area (at 12) pulsed, this beam is transported to a location close to said surface, and, at this location, the beam is amplified (at 15) and the amplified beam is sent to said surface, possibly via a dismissal. 2 - Procédé suivant la revendication 1, caractérisé en ce qu'on effectue le transport au moyen d'une fibre optique (18). 2 - Method according to claim 1, characterized in that the transport is carried out by means of an optical fiber (18). 3 - Procédé suivant la revendication 1 ou 2, caractérisé en ce qu'on envoie un gaz protecteur ou actif dans la région de travail pendant le travail au laser. 3 - Process according to claim 1 or 2, characterized in that a protective or active gas is sent into the working region during the laser work. 4 - Procédé suivant l'une quelconque des revendications 1 à 3, caractérisé en ce que l'on confine la région de travail et, pendant le travail au laser, on aspire le gaz contenu dans la région confinée. 4 - Process according to any one of claims 1 to 3, characterized in that the working region is confined and, during laser work, the gas contained in the confined region is sucked. 5 - Procédé suivant l'une quelconque des revendications 1 à 4, caractérisé en ce qu'on fait passer le faisceau amplifié (37) à travers un orifice (40) d'une électrode (39) parallèle à ladite surface, et on crée un champ électrique entre cette électrode et ladite surface pendant le travail au laser. 5 - Method according to any one of claims 1 to 4, characterized in that the amplified beam (37) is passed through an orifice (40) of an electrode (39) parallel to said surface, and one creates an electric field between this electrode and said surface during laser work. 6 - Procédé suivant l'une quelconque des revendications 1 à 5, pour la décontamination de ladite surface (3 à 5), caractérisé en ce qu'on utilise un faisceau laser qui, après amplification, possède des impulsions ayant une énergie de 0,3 à 5 joules, ou plus, une durée de 10 à 30 ns, et une densité d'énergie de 1 à 15 J/cm2. 6 - Method according to any one of claims 1 to 5, for the decontamination of said surface (3 to 5), characterized in that a laser beam is used which, after amplification, has pulses having an energy of 0, 3 to 5 joules, or more, a duration of 10 to 30 ns, and an energy density of 1 to 15 J / cm2. 7 - Equipement de travail au laser sur une surface (3, 4, 5) contenue dans une zone contaminée (2) d'une installation nucléaire, caractérisé en ce qu'il comprend : - un générateur de faisceau laser pulsé (12) disposé en dehors de la zone contaminée (2); - un amplificateur de faisceau laser (15); - des moyens (18) de transport du faisceau laser pulsé jusqu'à l'entrée de cet amplificateur; et - des moyens (21) pour déplacer l'amplificateur (15) en regard de ladite surface et au voisinage de celle-ci. 7 - Laser work equipment on a surface (3, 4, 5) contained in a contaminated area (2) a nuclear installation, characterized in that it comprises: - a pulsed laser beam generator (12) disposed outside the contaminated area (2); - a laser beam amplifier (15); - Means (18) for transporting the pulsed laser beam to the input of this amplifier; and - Means (21) for moving the amplifier (15) opposite said surface and in the vicinity thereof. 8 - Equipement suivant la revendication 7, caractérisé en ce que le générateur (12) est du type Nd-YAG, saphir ou excimère, éventuellement muni d'un miroir gaussien de renvoi, et en ce que lesdits moyens de transport (18) comprennent une fibre optique. 8 - Equipment according to claim 7, characterized in that the generator (12) is of the Nd-YAG, sapphire or excimer type, optionally provided with a Gaussian return mirror, and in that said means of transport (18) comprise an optical fiber. 9 - Equipement suivant la revendication 8, caractérisé en ce que la fibre optique (18) a une longueur d'au moins 15 m environ. 9 - Equipment according to claim 8, characterized in that the optical fiber (18) has a length of at least about 15 m. 10 - Equipement suivant l'une quelconque des revendications 7 à 9, caractérisé en ce qu'il comprend un miroir de renvoi (38) monté en sortie de l'amplificateur (15) et éventuellement mobile par rapport à celui-ci. 10 - Equipment according to any one of claims 7 to 9, characterized in that it comprises a deflection mirror (38) mounted at the output of the amplifier (15) and possibly movable relative to the latter. 11 - Equipement suivant l'une quelconque des revendications 7 à 10, caractérisé en ce qu'il comprend une enceinte de confinement (16) mobile solidairement avec l'amplificateur (15) ou avec le miroir (38) et munie de moyens d'aspiration (13, 14, 20) et éventuellement de moyens (19) d'introduction d'un gaz protecteur ou actif. 11 - Equipment according to any one of claims 7 to 10, characterized in that it comprises a confinement enclosure (16) movable integrally with the amplifier (15) or with the mirror (38) and provided with means of suction (13, 14, 20) and possibly means (19) for introducing a protective or active gas. 12 - Equipement suivant l'une quelconque des revendications 7 à 11, caractérisé en ce qu'il comprend une électrode (39) parallèle à ladite surface, percée d'un orifice (40) de passage du faisceau laser amplifié et mobile solidairement avec l'amplificateur (15), et des moyens (41) pour créer un champ électrique entre cette électrode et ladite surface. 12 - Equipment according to any one of claims 7 to 11, characterized in that it comprises an electrode (39) parallel to said surface, pierced with an orifice (40) for passage of the amplified laser beam and movable integrally with the amplifier (15), and means (41) for creating an electric field between this electrode and said surface.
EP92400622A 1991-04-05 1992-03-10 Process and equipment for working with a laser in a contaminated area of a nuclear plant Expired - Lifetime EP0507641B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR919104189A FR2674983B1 (en) 1991-04-05 1991-04-05 LASER WORKING PROCESS AND EQUIPMENT IN A CONTAMINATED AREA OF A NUCLEAR FACILITY.
FR9104189 1991-04-05

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EP0507641A1 true EP0507641A1 (en) 1992-10-07
EP0507641B1 EP0507641B1 (en) 1995-09-20

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KR (1) KR920020528A (en)
CA (1) CA2062623A1 (en)
DE (1) DE69204879T2 (en)
ES (1) ES2078681T3 (en)
FR (1) FR2674983B1 (en)
RU (1) RU2084978C1 (en)
TW (1) TW201356B (en)
ZA (1) ZA922453B (en)

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EP0724929A2 (en) * 1995-01-31 1996-08-07 Kabushiki Kaisha Toshiba Underwater laser processing method and apparatus
GB2391691A (en) * 2002-08-07 2004-02-11 Remote Marine Systems Ltd Method and apparatus for removing material from a target object
FR2879101A1 (en) * 2004-12-14 2006-06-16 Cogema LASER DECONTAMINATION OF THE SURFACE OF A PROFILE PIECE.
US8369473B2 (en) 2005-12-09 2013-02-05 Areva Nc Device and method for the automated decontamination of a nuclear fuel rod
CN104438227A (en) * 2013-09-16 2015-03-25 上海海固电器设备有限公司 Airplane coated paint laser cleaning equipment
CN112605068A (en) * 2020-12-15 2021-04-06 湖南大学 Irradiation-resistant variable-focus laser cleaning device and using method
CN113198802A (en) * 2021-05-17 2021-08-03 圣同激光设备(上海)有限公司 Large-breadth laser cleaning machine

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RU2199162C1 (en) * 2001-10-08 2003-02-20 Максимов Лев Николаевич Method and device for recovering spent nuclear fuel
RU2468457C1 (en) * 2011-08-03 2012-11-27 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Санкт-Петербургский национальный исследовательский университет информационных технологий, механики и оптики" Method for removing radioactive film from object surface
CN104438230A (en) * 2014-11-17 2015-03-25 成都莱普科技有限公司 Industrial product laser cleaning system and control method thereof
FR3100002B1 (en) 2019-08-21 2021-11-19 Onet Tech Cn Process for decontaminating by pulsed laser a metal part comprising on its surface a layer of metal oxides

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0724929A2 (en) * 1995-01-31 1996-08-07 Kabushiki Kaisha Toshiba Underwater laser processing method and apparatus
EP0724929A3 (en) * 1995-01-31 1997-08-20 Toshiba Kk Underwater laser processing method and apparatus
US5790620A (en) * 1995-01-31 1998-08-04 Kabushiki Kaisha Toshiba Underwater laser processing method and apparatus
US6084202A (en) * 1995-01-31 2000-07-04 Kabushiki Kaisha Toshiba Underwater laser processing method and apparatus
GB2391691A (en) * 2002-08-07 2004-02-11 Remote Marine Systems Ltd Method and apparatus for removing material from a target object
GB2391691B (en) * 2002-08-07 2006-02-08 Remote Marine Systems Ltd Method and apparatus for removing material from a target object
FR2879101A1 (en) * 2004-12-14 2006-06-16 Cogema LASER DECONTAMINATION OF THE SURFACE OF A PROFILE PIECE.
WO2006064156A1 (en) * 2004-12-14 2006-06-22 Compagnie Generale Des Matieres Nucleaires Laser decontamination of the surface of a shaped component
US8369473B2 (en) 2005-12-09 2013-02-05 Areva Nc Device and method for the automated decontamination of a nuclear fuel rod
CN104438227A (en) * 2013-09-16 2015-03-25 上海海固电器设备有限公司 Airplane coated paint laser cleaning equipment
CN112605068A (en) * 2020-12-15 2021-04-06 湖南大学 Irradiation-resistant variable-focus laser cleaning device and using method
CN113198802A (en) * 2021-05-17 2021-08-03 圣同激光设备(上海)有限公司 Large-breadth laser cleaning machine
CN113198802B (en) * 2021-05-17 2022-07-12 圣同激光设备(上海)有限公司 Large-breadth laser cleaning machine

Also Published As

Publication number Publication date
KR920020528A (en) 1992-11-21
FR2674983A1 (en) 1992-10-09
DE69204879T2 (en) 1996-04-04
EP0507641B1 (en) 1995-09-20
CA2062623A1 (en) 1992-10-06
ZA922453B (en) 1993-10-04
TW201356B (en) 1993-03-01
ES2078681T3 (en) 1995-12-16
FR2674983B1 (en) 1994-08-05
DE69204879D1 (en) 1995-10-26
RU2084978C1 (en) 1997-07-20

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