EP0185393B1 - Process for decontaminating the surface of an object - Google Patents

Process for decontaminating the surface of an object Download PDF

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Publication number
EP0185393B1
EP0185393B1 EP85116401A EP85116401A EP0185393B1 EP 0185393 B1 EP0185393 B1 EP 0185393B1 EP 85116401 A EP85116401 A EP 85116401A EP 85116401 A EP85116401 A EP 85116401A EP 0185393 B1 EP0185393 B1 EP 0185393B1
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Prior art keywords
decontaminating
layer
agent
material contains
forming material
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German (de)
French (fr)
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EP0185393A1 (en
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Heinrich Dr. Dipl.-Chem. Weichselgartner
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Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
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Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
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    • 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

Definitions

  • the present invention relates to a method for decontaminating a surface of an object, in which a removable layer of a decontaminating and a layer-forming material is produced on the surface and the layer with the impurities contained therein is then removed from the surface.
  • the task often arises of cleaning the surface of radioactive or chemically contaminated objects (“decontaminate”).
  • the objects to be decontaminated can be as diverse as superficially highly radioactive metallic structures from nuclear reactors and a weakly contaminated work table from a tritium laboratory.
  • Decontamination processes have proven to be particularly expedient in which a strippable layer is formed on the surface to be decontaminated.
  • a strippable layer is formed on the surface to be decontaminated.
  • Such a method is known from DD-A-81048, in which a viscous mixture of decontaminating and film-forming material is applied to the surface to be decontaminated, which mixture contains formaldehyde and ammonium rhodanide for decontamination and polyvinyl alcohol as film former.
  • Complexing agents, detergents and / or organic acids can be added to the solution for decontamination enhancement.
  • EP-A-47 857 also discloses a process for the decontamination of radioactive contaminated surfaces, in which a pickling paste is applied to the surfaces to be decontaminated, which contains a pickling agent, a wetting agent, a filler and an aqueous, film-forming, agent-resistant plastic dispersion.
  • the mordant can contain a mixture of nitric acid, hydrochloric acid and hydrofluoric acid or concentrated hydrochloric acid with the addition of KJ or phosphoric acid with zinc oxide and sodium nitrite.
  • Aqueous copolymer dispersion of vinyl acetate, ethylene and vinyl chloride and copolymer dispersions of methacrylic acid esters are used as the film-forming component.
  • the present invention avoids this disadvantage in that only the decontaminating material is first applied to the surface and allowed to act, and only then is the layer-forming material applied in such a way that it absorbs the decontaminating material before it solidifies into the removable layer.
  • the decontaminating material or mordant can be left to act for as long as desired and the materials which can be used are also freer, since decontaminating materials which are intrinsically difficult to use with film formers can be modified before the film former is applied so that a good tolerance is guaranteed.
  • the method can also be easily adapted to different surfaces and / or contaminations and / or degrees of contamination.
  • a material is first applied to the contaminated surface in several steps, which can remove the contaminants from the surface and, if desired, attack the surface and dissolve it on the surface. Then a layer-forming material (film former) is applied, which is able to absorb the previously applied decontaminating material with the impurities contained therein and then to solidify into a coherent solid body.
  • film former a layer-forming material
  • the solid body thus preferably has the shape of a coherent, flexible, film-like structure which can be easily removed from the cleaned surface.
  • the process can easily be repeated with the same or a modified material system.
  • thixotropic materials such as amorphous silica (Si0 2 ) can be prevented that the pickling mixture of vertical walls u. The like. runs down before it causes the film formation by adding resin or another kenden material is solidified to the peelable film.
  • a second step which can be timed to the degree and type of contamination, etc., then an aggressive, in particular an inorganic pickling agent is applied, if necessary with the addition of the gel or thickening agent in order to run away, drip off or the like . to prevent.
  • a further component is applied which, alone or in cooperation with components of the previously applied layer (s), leads to the formation of a coherent, elastic layer or film.
  • the constituents, in particular matrix constituents, of the material applied in the first and second process step can simply be incorporated into the film-forming material applied in this process step or can react with this material by coagulation, precipitation or hardening.
  • the film formed which contains all constituents, including the contaminants removed from the surface, can be removed, e.g. B. be deducted.
  • Effective decontamination agents for radioactively contaminated metallic surfaces should dissolve the radioactive coating and remove it from the system: furthermore, they should not be too corrosive to the surfaces; The same applies of course to chemical contaminants.
  • Glasses and organic surfaces can have ionizable acidic groups that interact with strong cationic contaminants like ion exchangers. This contamination can then be removed by complexing agents.
  • Acrylic glass, PTFE, PE and rubber can be treated with mixtures of 20% HN0 3 and 3% HF or complexing agents with detergents.
  • halogens in particular chlorides and especially free chlorine, should be avoided if possible for reasons of corrosion.
  • organic solvents such as ketones and hydrocarbons, especially halogenated hydrocarbons, be used in order not to put additional strain on the exhaust air carbon filters for iodine retention, which are normally present in radioactive waste disposal plants.
  • Alcohols including higher ones, such as butyl alcohol, can generally be used.
  • surfactants or detergents and relatively weak pickling chemicals are preferably added.
  • the detergents cause degreasing of the surfaces and the weak, e.g. B. organic reagents such as oxalic acid, citric acid or lactic acid cause a first surface attack, which improves the adhesion necessary for the further film build-up.
  • more aggressive pickling chemicals can then be applied, e.g. B. phosphoric acid with additives to inhibitors and complexing agents, optionally together with gels and thickeners and / or a component of the layer-forming material.
  • the matrix e.g. B. by application of curable resins, such as urea, melamine and phenolic resins or by a second component that reacts with a previously applied component to form a layer, to form the “peelable film”.
  • curable resins such as urea, melamine and phenolic resins
  • a second component that reacts with a previously applied component to form a layer
  • the embedded aqueous components and organic components ensure that the films remain elastic and flexible so that they come together after a corresponding «curing time» can be peeled off without leaving any sticky or dried layers on the surface due to embrittlement or drying out.
  • the formation of the film can also be achieved by adding salts (borax, sulfates or carbonates), since these act gelling or even precipitating.
  • Vinnapas dispersions copolymers of vinyl acetate and higher fatty acid vinyl esters

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  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Food Science & Technology (AREA)
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  • Treatments Of Macromolecular Shaped Articles (AREA)
  • Detergent Compositions (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Details Or Accessories Of Spraying Plant Or Apparatus (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
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Abstract

1. Process for decontaminating the surface of an object in which a removable layer of a decontaminating and a layer-forming material is produced on the surface and then the layer is removed from the surface with the impurities contained in it, characterised in that firstly only the decontaminating material is applied to the surface and allowed to act and subsequently the layer-forming material is so applied that it absorbs the decontaminating material before its solidification into the removable layer.

Description

Die vorliegende Erfindung betrifft ein Verfahren zum Dekontaminieren einer Oberfläche eines Gegenstandes, bei welchem auf der Oberfläche eine abziehbare Schicht aus einem dekontaminierenden und einem schichtbildenden Material erzeugt und dann die Schicht mit den in ihr enthaltenen Verunreinigungen von der Oberfläche entfernt wird.The present invention relates to a method for decontaminating a surface of an object, in which a removable layer of a decontaminating and a layer-forming material is produced on the surface and the layer with the impurities contained therein is then removed from the surface.

In Wissenschaft und Technik tritt häufig die Aufgabe auf, die Oberfläche radioaktiv oder chemisch verunreinigter Gegenstände zu reinigen (« dekontaminieren •). Die zu dekontaminierenden Gegenstände können so verschieden sein wie oberflächlich hochradioaktiv metallische Strukturen aus Kernreaktoren und ein schwach kontaminierter Arbeitstisch aus einem Tritiumlabor.In science and technology, the task often arises of cleaning the surface of radioactive or chemically contaminated objects (“decontaminate”). The objects to be decontaminated can be as diverse as superficially highly radioactive metallic structures from nuclear reactors and a weakly contaminated work table from a tritium laboratory.

Als besonders zweckmäßig haben sich Dekontaminierungsverfahren erwiesen, bei denen auf der zu dekontaminierenden Oberfläche eine abziehbare Schicht gebildet wird. Aus DD-A-81048 ist ein solches Verfahren bekannt, bei dem auf die zu dekontaminierende Oberfläche eine dickflüssige Mischung aus dekontaminierendem und filmbildendem Material aufgetragen wird, welche zur Dekontaminierung Formaldehyd und Ammoniumrhodanid und als Filmbildner Polyvinylalkohol enthält. Der Lösung können zur Dekontaminationsverstärkung Komplexbildner, Detergentien und/oder organische Säuren zugesetzt werden.Decontamination processes have proven to be particularly expedient in which a strippable layer is formed on the surface to be decontaminated. Such a method is known from DD-A-81048, in which a viscous mixture of decontaminating and film-forming material is applied to the surface to be decontaminated, which mixture contains formaldehyde and ammonium rhodanide for decontamination and polyvinyl alcohol as film former. Complexing agents, detergents and / or organic acids can be added to the solution for decontamination enhancement.

Aus der EP-A-47 857 ist ferner ein Verfahren zur Dekontamination radioaktiv verunreinigter Oberflächen bekannt, bei dem auf die zu dekontaminierenden Oberflächen eine Beizpaste aufgetragen wird, die ein Beizmittel, ein Netzmittel, einen Füllstoff und eine wässrige, filmbildende, beizmittelresistente Kunststoffdispersion enthält. Das Beizmittel kann eine Mischung aus Salpetersäure, Salzsäure und Flußsäure oder konzentriete Salzsäure mit Zusatz von KJ oder Phosphorsäure mit Zinkoxid und Natriumnitrit enthalten. Als filmbildende Komponente werden wässrige Copolymerisatdispersion aus Vinylacetat, Ethylen und Vinylchlorid sowie Copolymerisatdispersionen aus Methacrylsäureestern verwendet.EP-A-47 857 also discloses a process for the decontamination of radioactive contaminated surfaces, in which a pickling paste is applied to the surfaces to be decontaminated, which contains a pickling agent, a wetting agent, a filler and an aqueous, film-forming, agent-resistant plastic dispersion. The mordant can contain a mixture of nitric acid, hydrochloric acid and hydrofluoric acid or concentrated hydrochloric acid with the addition of KJ or phosphoric acid with zinc oxide and sodium nitrite. Aqueous copolymer dispersion of vinyl acetate, ethylene and vinyl chloride and copolymer dispersions of methacrylic acid esters are used as the film-forming component.

Die oben erwähnten bekannten Verfahren haben zwar den Vorteil, daß kontaminierte Flächen in situ dekontaminiert werden können, daß kontaminierter Abfall lediglich in kompakter und fester Form anfällt und daß ein Abwaschen bzw. Spülen der dekontaminierten Oberflächen entfällt, somit auch jede Verdünnung und weitere Verbreitung von Aktivität oder Verunreinigungen. Nachteilig ist jedoch, daß die für die Einwirkung der Kontaminierungs- und Beizmittel zur Verfügung stehenden Zeit durch das Aushärten der filmbildenden Komponente begrenzt ist, so daß die Kontaminierungswirkung häufig zu wünschen übrig läßt.The known methods mentioned above have the advantage that contaminated areas can be decontaminated in situ, that contaminated waste is only obtained in a compact and solid form and that washing or rinsing of the decontaminated surfaces is omitted, thus also any dilution and further spread of activity or impurities. However, it is disadvantageous that the time available for the action of the contaminants and pickling agents is limited by the curing of the film-forming component, so that the contaminant effect often leaves something to be desired.

Die vorliegende Erfindung vermeidet diesen Nachteil dadurch, daß man zuerst nur das dekontaminierende Material auf die Oberfläche aufbringt und einwirken läßt und anschließend dann erst das schichtbildende Material so aufbringt, daß es vor seiner Verfestigung zu der abziehbaren Schicht das dekontaminierende Material aufnimmt.The present invention avoids this disadvantage in that only the decontaminating material is first applied to the surface and allowed to act, and only then is the layer-forming material applied in such a way that it absorbs the decontaminating material before it solidifies into the removable layer.

Bei dem erfindungsgemäßen Verfahren kann man das dekontaminierende Material oder Beizmittel beliebig lange einwirken lassen und man ist auch hinsichtlich der verwendbaren Materialien freier, da man dekontaminierende Materialien, die an sich schwer mit Filmbildnern verträglich sind, vor dem Aufbringen des Filmbildners so modifizieren kann, daß eine gute Verträglichkeit gewährleistet ist.In the process according to the invention, the decontaminating material or mordant can be left to act for as long as desired and the materials which can be used are also freer, since decontaminating materials which are intrinsically difficult to use with film formers can be modified before the film former is applied so that a good tolerance is guaranteed.

Das Verfahren kann auch leicht an verschiedene Oberflächen und/oder Verunreinigungen und/oder Verunreinigungsgrade angepaßt werden.The method can also be easily adapted to different surfaces and / or contaminations and / or degrees of contamination.

Bei dem vorliegenden Verfahren wird auf die kontaminierte Oberfläche in mehreren Schritten zuerst ein Material aufgebracht, das die Verunreinigungen von der Oberfläche zu entfernen sowie, falls gewünscht, die Oberfläche anzugreifen und oberflächlich aufzulösen vermag. Dann wird ein schichtbildendes Material (Filmbildner) aufgebracht, das das vorher aufgebrachte dekontaminierende Material mit den in diesem enthaltenen Verunreinigungen aufzunehmen und sich dann zu einem zusammenhängenden festen Körper zu verfestigen vermag. Anschließend wird der verfestigte, vorzugsweise elastische, schichtartige Körper, der die von der Oberfläche entfernten Verunreinigungen enthält, von der Oberfläche abgenommen. Der feste Körper hat also vorzugsweise die Form eines zusammenhängenden, flexiblen, folienartigen Gebildes, das sich von der gereinigten Oberfläche leicht abziehen läßt.In the present method, a material is first applied to the contaminated surface in several steps, which can remove the contaminants from the surface and, if desired, attack the surface and dissolve it on the surface. Then a layer-forming material (film former) is applied, which is able to absorb the previously applied decontaminating material with the impurities contained therein and then to solidify into a coherent solid body. The solidified, preferably elastic, layer-like body, which contains the contaminants removed from the surface, is then removed from the surface. The solid body thus preferably has the shape of a coherent, flexible, film-like structure which can be easily removed from the cleaned surface.

Das Verfahren läßt sich ohne weiteres mit dem gleichen oder einem abgeänderten Materialsystem wiederholen.The process can easily be repeated with the same or a modified material system.

Das vorliegende mehrstufige Verfahren zur Oberflächendekontamination kann z. B. wie folgt durchgeführt werden :

  • a) Durch Aufstreichen, Aufspritzen mittels einer Hochdruck-Kolbenpumpe oder irgendein anderes geeignetes Verfahren wird auf die zu dekontaminierende Oberfläche eine erste Schicht aufgebracht, die in einer pastosen oder gelartigen Matrix Lösungsmittel, oberflächenaktive Substanzen (Tenside) und schwache (organische) Beizmittel enthalten kann. Diese Schicht hat die Aufgabe, die Oberfläche zu entfetten und gleichzeitig so vorzubereiten (vorzubeizen), daß eine gute Haftung des Matrixmaterials einerseits und ein optimaler Angriff eines anschließend aufgebrachten aggressiven Beizmittels gewährleistet ist.
The present multi-stage process for surface decontamination can e.g. B. can be carried out as follows:
  • a) By brushing, spraying on using a high-pressure piston pump or any other suitable method, a first layer is applied to the surface to be decontaminated, which may contain solvents, surface-active substances (surfactants) and weak (organic) mordants in a pasty or gel-like matrix. This layer has the task of degreasing the surface and at the same time preparing (pre-pickling) such that good adhesion of the matrix material on the one hand and optimal attack by an aggressive pickling agent subsequently applied is ensured.

Durch Zusatz von thixotropen Materialien, wie amorpher Kieselsäure (Si02) kann verhindert werden, daß das Beizgemisch von senkrechten Wänden u. dgl. herabläuft, ehe es durch Zugabe von Harz oder einem anderen die Filmbildung bewirkenden Material zu der abziehbaren Folie verfestigt wird.By adding thixotropic materials such as amorphous silica (Si0 2 ) can be prevented that the pickling mixture of vertical walls u. The like. runs down before it causes the film formation by adding resin or another kenden material is solidified to the peelable film.

b) In einem zweiten Schritt, der zeitlich auf den Grad und die Art der Verschmutzung usw. abgestimmt werden kann, wird sodann ein aggressives, insbesondere ein anorganisches Beizmittel aufgebracht, ggf. mit Zusatz des Gels oder Verdickungsmittels, um ein Weglaufen, Abtropfen oder dgl. zu verhindern.b) In a second step, which can be timed to the degree and type of contamination, etc., then an aggressive, in particular an inorganic pickling agent is applied, if necessary with the addition of the gel or thickening agent in order to run away, drip off or the like . to prevent.

Nach Beendigung des Beizvorganges gemäß dem zweiten Verfahrensschritt, dessen Dauer durch Vorversuche optimiert wird, bringt man eine weitere Komponente auf, welche für sich alleine oder in Zusammenwirken mit Bestandteilen der vorher aufgebrachten Schicht(en) zur Ausbildung einer zusammenhängenden, elastischen Schicht oder Folie führt. Die Bestandteile, insbesondere Matrixbestandteile des im ersten und zweiten Verfahrensschritt aufgetragenen Materials können in das in diesem Verfahrensschritt aufgetragene, filmbildende Material einfach inkorporiert werden oder mit diesem Material durch Koagulation, Ausfällen oder Aushärten reagieren. Nachdem die Schichtstruktur sich genügend verfestigt hat, kann die gebildete Folie, die alle Bestandteile, einschließlich der von der Oberfläche abgetragenen Verunreinigungen enthält, entfernt, z. B. abgezogen werden.After the pickling process has ended in accordance with the second process step, the duration of which is optimized by preliminary tests, a further component is applied which, alone or in cooperation with components of the previously applied layer (s), leads to the formation of a coherent, elastic layer or film. The constituents, in particular matrix constituents, of the material applied in the first and second process step can simply be incorporated into the film-forming material applied in this process step or can react with this material by coagulation, precipitation or hardening. After the layer structure has solidified sufficiently, the film formed, which contains all constituents, including the contaminants removed from the surface, can be removed, e.g. B. be deducted.

Im Rahmen des vorliegenden Verfahrens können beispielsweise die folgenden chemischen Dekontaminationsmittel verwendet werden :The following chemical decontamination agents can be used in the context of the present method:

Effektive Dekontaminationsmittel für radioaktiv verseuchte metallische Oberflächen sollen den radioaktiven Belag auflösen und ihn vom System entfernen : weiterhin sollen sie nicht allzu korrosiv auf die Oberflächen wirken ; analoges gilt selbstverständlich auch für chemische Verunreinigungen.Effective decontamination agents for radioactively contaminated metallic surfaces should dissolve the radioactive coating and remove it from the system: furthermore, they should not be too corrosive to the surfaces; The same applies of course to chemical contaminants.

Belaglösende Reagenzien sind beispielsweise Salpetersäure, Schwefelsäure, Phosphorsäure, Flußsäure, Oxalsäure und Citronensäure ;

  • Pufferreagenzien wie Amine sorgen für Erhaltung der Acidität ;
  • Korrosionsinhibitoren wie Hexamethylentetramin und Tribenzylamin werden an der Oberfläche adsorbiert und unterbinden Wasserstoff-Entwicklung ;
  • Komplexbildner wie Karbonate, Phosphate, Fluoride, Citrate, Tartrate, Diethylentriamin, Ethylendiamintetraessigsäure halten Metallionen in Lösung und verhindern deren Wiederanlagerung ;
  • Reduktionsmittel, wie Hydrazin, Hydroxylamin unterstützen das Durchdringen von oxidationsresistenten Filmen auf Edelstahl ;
  • Oxidationsmittel, wie Kaliumpermanganat oder Natriumdichromat, überführen die Metallionen in höhere Wertigkeitsstufen und erhöhen so deren Löslichkeit und
  • handelsübliche Tenside und Detergentien erleichtern die Ablösung von Schmier- und Fettfilmen.
Deposit-releasing reagents are, for example, nitric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, oxalic acid and citric acid;
  • Buffer reagents such as amines maintain acidity;
  • Corrosion inhibitors such as hexamethylenetetramine and tribenzylamine are adsorbed on the surface and prevent hydrogen evolution;
  • Complexing agents such as carbonates, phosphates, fluorides, citrates, tartrates, diethylenetriamine, ethylenediaminetetraacetic acid keep metal ions in solution and prevent their reassembly;
  • Reducing agents such as hydrazine and hydroxylamine support the penetration of oxidation-resistant films on stainless steel;
  • Oxidizing agents, such as potassium permanganate or sodium dichromate, convert the metal ions into higher valence levels and thus increase their solubility and
  • Commercial surfactants and detergents make it easier to remove grease and grease films.

Oft ist es nützlich, unterschiedliche Reagenzien abwechselnd einzusetzen und so die Effektivität zu erhöhen.It is often useful to use different reagents alternately to increase effectiveness.

Gläser und organische Oberflächen können ionisierbare saure Gruppen aufweisen, die mit starken kationischen Kontaminationen nach Art von lonenaustauschern in Wechselwirkung treten. Diese Kontamination kann dann durch Komplexbildner entfernt werden.Glasses and organic surfaces can have ionizable acidic groups that interact with strong cationic contaminants like ion exchangers. This contamination can then be removed by complexing agents.

Acrylglas, PTFE, PE und auch Gummi können mit Mischungen von 20 % HN03 und 3 % HF oder Komplexbildnern mit Detergentien behandelt werden.Acrylic glass, PTFE, PE and rubber can be treated with mixtures of 20% HN0 3 and 3% HF or complexing agents with detergents.

Als Matrixmaterial der ablösbaren Beizfolien können z. B. in Wasser oder organischen Lösungsmitteln quellbare Substanzen wie

  • Polyvinylalkohole, wasserlöslich ;
  • Polyvinylacetate, löslich in org. Lösungsmittel ;
  • Polyethylenglykole, in Wasser und org. Lösungsmitteln löslich Verwendung finden.
As the matrix material of the removable pickling films z. B. swellable substances in water or organic solvents such as
  • Polyvinyl alcohols, water soluble;
  • Polyvinyl acetates, soluble in org. Solvents;
  • Polyethylene glycols, in water and org. Solvents are used soluble.

Allgemein gilt, daß Halogene, insbesondere Chloride und vor allem freies Chlor aus Korrosionsgründen nach Möglichkeit vermieden werden sollen. Auch organische Lösungsmittel, wie Ketone und Kohlenwasserstoffe, insbesondere halogenierte Kohlenwasserstoffe, sollen nicht verwendet werden, um die Abluft-Kohlefilter zur Jodrückhaltung, die bei Anlagen zur Beseitigung radioaktiven Abfalls normalerweise vorhanden sind, nicht zusätzlich zu belasten. Alkohole, auch höhere, wie Butylalkohol sind im allgemeinen verwendbar.In general, halogens, in particular chlorides and especially free chlorine, should be avoided if possible for reasons of corrosion. Nor should organic solvents, such as ketones and hydrocarbons, especially halogenated hydrocarbons, be used in order not to put additional strain on the exhaust air carbon filters for iodine retention, which are normally present in radioactive waste disposal plants. Alcohols, including higher ones, such as butyl alcohol, can generally be used.

Beim Aufbringen der ersten Schichtkomponente werden vorzugsweise Tenside bzw. Detergentien und relativ schwache Beizchemikalien beigemischt. Die Detergentien bewirken eine Entfettung der Oberflächen und die schwachen, z. B. organischen Reagenzien wie Oxalsäure, Citronensäure oder Milchsäure bewirken einen ersten Oberflächenangriff, der die für den weiteren Filmaufbau notwendige Haftung verbessert.When the first layer component is applied, surfactants or detergents and relatively weak pickling chemicals are preferably added. The detergents cause degreasing of the surfaces and the weak, e.g. B. organic reagents such as oxalic acid, citric acid or lactic acid cause a first surface attack, which improves the adhesion necessary for the further film build-up.

In einem zweiten Verfahrensschritt können dann aggressivere Beizchemikalien aufgebracht werden, z. B. Phosphorsäure mit Zusätzen an Inhibitoren und Komplexbildnern, ggf. zusammen mit Gelen und Verdickungsmitteln und/oder einer Komponente des schichtbildenden Materials.In a second process step, more aggressive pickling chemicals can then be applied, e.g. B. phosphoric acid with additives to inhibitors and complexing agents, optionally together with gels and thickeners and / or a component of the layer-forming material.

In einem dritten und letzten Verfahrensschritt wird schließlich die Matrix, z. B. durch Applikation von härtbaren Harzen, wie Harnstoff-, Melamin-und Phenolharzen oder durch eine zweite Komponente, die mit einer vorher aufgebrachten Komponente unter Bildung einer Schicht reagiert, zur « abziehbaren Folie » ausgebildet. Die bislang mehr oder weniger gelförmig vorliegenden, locker aneinander haftenden Makromoleküle des Matrixmaterials, in dessen Zwischenräumen die Beizreagenzien und schließlich auch die vom Substrat abgelösten Metallionen, Radionuclide und kontaminierten Schmutz- und Fettschichten eingelagert worden waren, schließen sich dann z. B. durch Vernetzungsreaktionen zu einer aneinanderhängenden Schicht, dem Film oder der Folie zusammen.In a third and final process step, the matrix, e.g. B. by application of curable resins, such as urea, melamine and phenolic resins or by a second component that reacts with a previously applied component to form a layer, to form the “peelable film”. The hitherto more or less gel-like, loosely adhering macromolecules of the matrix material, in the interstices of which the pickling reagents and finally the metal ions, radionuclides and contaminated dirt and fat layers detached from the substrate, were then closed. B. together by crosslinking reactions to form a contiguous layer, the film or the film.

Die eingelagerten wässrigen Bestandteile und organischen Komponenten bewirken dabei, daß die Filme elastisch und flexibel bleiben, so daß sie nach entsprechender « Aushärtezeit » zusammenhängend abgezogen werden können, ohne daß infolge von Versprödung oder Austrocknung an der Oberfläche klebende oder aufgetrocknete Schichten zurückbleiben.The embedded aqueous components and organic components ensure that the films remain elastic and flexible so that they come together after a corresponding «curing time» can be peeled off without leaving any sticky or dried layers on the surface due to embrittlement or drying out.

Beispiel 1example 1

Abziehbare Beizfolie auf der Basis von Polyvinylacetaten, z. B. Polyvinylbutyral :

  • 1. Pulverförmiges Polyvinylbutyral wird in
    • 1.1 einem organischen Lösungsmittel gelöst, wie Isopropylalkohol oder Äthylglykol.
    • 1.2 Polyethylenglykol (HO(CH2―CH2―0)n―H) wird als
      • a) Verdicker
      • b) Komplexbildner (Additionsverbindung mit Säuren, Salzen, Harnstoff u. a.)
      • c) Esterbildner (mit zweibasischen Carbonsäuren erhöhte Elastizität der Filme)
      • d) Lösungsvermittler (für Säuren etc., wie H2S04 oder H3P04) zugegeben und weiterhin
    • 1.3 Tenside und Detergentien, wie Laurylsulfonat zum Entfetten sowie
    • 1.4 Zitronensäure als erstes Beizmittel und
    • 1.5 Milchsäure
      • als Beizmittel
      • als Mischkomponente zur Unterstützung des Phasenübergangs organisch/wässrig beigemischt.' Diese pastöse Mischung wird auf die zu dekontaminierende Oberfläche durch Aufstreichen oder Aufspritzen in dicker Schicht aufgetragen.
      • Nach einer, durch Vorversuche zu bestimmenden Einwirkzeit (z. B. 15 - 60 Minuten) wird die
  • 2. Komponente, bestehend aus mit
    • 2.1 Polyethylenglykol verdickter
    • 2.2 O-Phosphorsäure zusätzlich auf die erste Schicht aufgetragen. Falls erforderlich, kann noch weitere
    • 2.3 Milchsäure zugegeben werden, um die Mischbarkeit mit organischen Lösungsmitteln zu verbessern.
  • 3. Mit der dritten Komponente schließlich wird eine reaktive polymerisierbare Komponente oder Harzkomponente, in einem geeigneten Lösungsmittel gelöst, auf die ersten beiden Schichten aufgetragen. Dazu werden z. B.
    • 3.1 Phenolharze, wie Phenodur, gelöst in
    • 3.2 Butylglykol, Ethylglykol oder in einer Mischung aus beiden Glykolen, oder
    • 3.3 Melaminharze, wie Hexamethoxymethylmelamin in einem
    • 3.4 Lösungsmittelgemisch
      • aus Isopropanol, Butylacetat,
      • und Ethylglykol gelöst, oder
    • 3.5 Harnstoffharze, gelöst in
    • 3.6 Alkoholen (Ethanol, Butanol) aufgespritzt.
Removable pickling film based on polyvinyl acetates, e.g. B. Polyvinyl butyral:
  • 1. Powdery polyvinyl butyral is in
    • 1.1 dissolved in an organic solvent, such as isopropyl alcohol or ethyl glycol.
    • 1.2 Polyethylene glycol (HO (CH2 ― CH2―0) n ― H) is considered
      • a) thickener
      • b) complexing agent (addition compound with acids, salts, urea, etc.)
      • c) ester former (with dibasic carboxylic acids increased elasticity of the films)
      • d) solubilizers (for acids etc., such as H 2 S0 4 or H 3 P0 4 ) added and continue
    • 1.3 surfactants and detergents such as lauryl sulfonate for degreasing and
    • 1.4 Citric acid as the first mordant and
    • 1.5 lactic acid
      • as a mordant
      • added as a mixing component to support the phase transition organic / aqueous. ' This pasty mixture is applied to the surface to be decontaminated by brushing or spraying in a thick layer.
      • After an exposure time to be determined by preliminary tests (e.g. 15 - 60 minutes), the
  • 2. component consisting of with
    • 2.1 Thickened polyethylene glycol
    • 2.2 Additionally apply O-phosphoric acid to the first layer. If necessary, more can be done
    • 2.3 Lactic acid can be added to improve miscibility with organic solvents.
  • 3. Finally, with the third component, a reactive polymerizable component or resin component, dissolved in a suitable solvent, is applied to the first two layers. For this z. B.
    • 3.1 Phenolic resins, such as Phenodur, dissolved in
    • 3.2 butyl glycol, ethyl glycol or in a mixture of both glycols, or
    • 3.3 melamine resins, such as hexamethoxymethylmelamine in one
    • 3.4 Solvent mixture
      • from isopropanol, butyl acetate,
      • and dissolved ethyl glycol, or
    • 3.5 urea resins, dissolved in
    • 3.6 Alcohols (ethanol, butanol) sprayed on.

Kombinationen mit Harnstoffharzen härten gewöhnlich schnell aus. Es können verwendet werden

  • Plastopal RH (BASF)
  • Soamin 85 (SOAB)
  • Melaminharze :
    • Maprenal PSX (Hoechst)
    • Cymel 300 (Cyanamid)
  • Phenolharze :
    • Phenodur PF 285.
Combinations with urea resins usually harden quickly. It can be used
  • Plastopal RH (BASF)
  • Soamin 85 (SOAB)
  • Melamine resins:
    • Maprenal PS X (Hoechst)
    • Cymel 300 (cyanamide)
  • Phenolic resins:
    • Phenodur PF 285.

Beispiel 2Example 2

Abziehbare Folie auf der Basis von wasserlöslichen Polyvinylalkoholen

  • 1. Pulverförmiges PVA-Ausgangsmateriat. z. B. Wacker Polyviol B 08/140 oder M 13/140 wird in kaltem Wasser unter Rühren aufgelöst, Weichmacher wie beispielsweise Äthylenglycol und Tenside sowie Zitronensäure und Milchsäure als milde Beizmittel zugegeben. Zum Andicken kann wiederum Polyethylenglykol verwendet werden.
  • 2. Nach vorgegebener Einwirkzeit, in der die Tenside die metallische Oberfläche entfettet haben und die gelförmige Paste aufgrund der Beizwirkung der organischen Säuren gut auf dem zu dekontaminierenden Untergrund haftet, werden 0-Phosphorsäure und weitere Anteile an Zitronensäure und Milchsäure, angedickt mit Polyethylenglykol aufgebracht und die Oberfläche stärker angebeizt.
  • 3. Die Ausbildung zur plastischen, abziehbaren Folie erfolgt in diesem Falle durch Aufbringung organischer Lösungsmittel, vorzugsweise höherer Alkohole wie z. B. Butylalkohol, die wiederum angedickt appliziert werden.
Peelable film based on water-soluble polyvinyl alcohols
  • 1. Powdered PVA starting material. e.g. B. Wacker Polyviol B 08/140 or M 13/140 is dissolved in cold water with stirring, plasticizers such as ethylene glycol and surfactants as well as citric acid and lactic acid are added as mild pickling agents. Polyethylene glycol can in turn be used for thickening.
  • 2. After the specified exposure time, in which the surfactants have degreased the metallic surface and the gel-like paste adheres well to the surface to be decontaminated due to the pickling effect of the organic acids, 0-phosphoric acid and further portions of citric acid and lactic acid, thickened with polyethylene glycol, are applied and the surface stained more strongly.
  • 3. The formation of a plastic, peelable film is carried out in this case by applying organic solvents, preferably higher alcohols such as. B. butyl alcohol, which in turn are applied thickened.

Auch durch die Zugabe von Salzen (Borax, Sulfaten oder Carbonaten) kann die Ausbildung der Folie erzielt werden, da diese gelierend bzw. sogar fällend wirken.The formation of the film can also be achieved by adding salts (borax, sulfates or carbonates), since these act gelling or even precipitating.

4. Auch der Zusatz von Vinnapas-Dispersionen (Copolymerisate von Vinylacetat und höheren Fettsäurevinylestern) verbessert die Ausbildung dicker, gut abziehbarer Folien.4. The addition of Vinnapas dispersions (copolymers of vinyl acetate and higher fatty acid vinyl esters) also improves the formation of thick, easily removable films.

Claims (15)

1. Process for decontaminating the surface of an object in which a removable layer of a decontaminating and a layer-forming material is produced on the surface and then the layer is removed from the surface with the impurities contained in it, characterised in that firstly only the decontaminating material is applied to the surface and allowed to act and subsequently the layer-forming material is so applied that it absorbs the decontaminating material before its solidification into the removable layer.
2. Process as claimed in claim 1, characterised in that the decontaminating material contains a cleansing agent and a chemically aggressive corrosive agent.
3. Process as claimed in claim 2, characterised in that the cleansing agent contains a surface active substance and/or a solvent and/or a weak organic corrosive agent.
4. Process as claimed in claim 1, 2 or 3, characterised in that the decontaminating and/or the layer-forming material has a pasty or gel-like consistency.
5. Process as claimed in one of the preceding claims, characterised in that the decontaminating and/or the layer-forming material contains a gel or a thickening agent.
6. Process as claimed in one of the preceding claims, characterised in that the layer-forming material contains a polymerisable compound.
7. Method as claimed in claim 1, 2 or 3, characterised in that
a) firstly a first liquid or pasty or gel-like material, which contains a surface active substance and/or a solvent and/or a weak organic corrosive agent, is applied to the surface,
b) the second liquid, pasty or gel-like material, which contains a chemically aggressive inorganic corrosive agent, is applied to the surface, and
c) subsequently a third material is applied which is miscible with the first two materials and on application to these materials forms with them the coherent, flexible removable layer.
8. Process as claimed in one of the preceding claims, characterised in that the decontaminating material contains a buffer reagent, such as an amine.
9. Process as claimed in one of the preceding claims, characterised in that the decontaminating material contains a corrosion inhibitor, such as hexamethylene tetramine and tribenzyl amine.
10. Process as claimed in one of the preceding claims, characterised in that the decontaminating material contains a sequestering agent, such as a carbonate, phosphate, fluoride, citrate, tartrate, diethyl triamine, ethylene diamine tetraacetic acid.
11. Process as claimed in one of the preceding claims, characterised in that the decontaminating. material contains a reducing agent, such as hydrazine or hydroxylamine.
12. Process as claimed in one of claims 1 to 10, characterised in that the decontaminating material contains an oxidizing agent, such as potassium permanganate and sodium dichromate.
13. Process as claimed in claim 1, characterised in that the decontaminating material contains ethylene glycol and/or polyethylene glycol and/or a tenside and/or citric acid and/or orthophosphoric acid.
14. Process as claimed in claim 1, characterised in that the layer-forming material contains polyvinyl formal and/or polyvinyl butyral and/or a ureaformaldehyde resin solution.
15. Process as claimed in one of the preceding claims, characterised in that the decontaminating material is free from halogens, in particular free from chlorine.
EP85116401A 1984-12-21 1985-12-20 Process for decontaminating the surface of an object Expired EP0185393B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85116401T ATE30804T1 (en) 1984-12-21 1985-12-20 METHOD OF DECONTAMINATING THE SURFACE OF AN OBJECT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19843446931 DE3446931A1 (en) 1984-12-21 1984-12-21 METHOD FOR DECONTAMINATING THE SURFACE OF AN OBJECT
DE3446931 1984-12-21

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EP0185393B1 true EP0185393B1 (en) 1987-11-11

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2656949B1 (en) * 1990-01-09 1994-03-25 Commissariat A Energie Atomique DECONTAMINANT GEL AND ITS USE FOR RADIOACTIVE DECONTAMINATION OF SURFACES.
FR2717709B1 (en) * 1994-03-22 1996-04-26 Commissariat Energie Atomique Gel capable of retaining radioactive contamination and its use to protect or decontaminate a surface.
DE19521236C2 (en) * 1995-06-10 1999-08-05 Nukem Gmbh Process for decontaminating the boundaries of closed areas
WO1997030457A1 (en) * 1996-02-12 1997-08-21 Siemens Aktiengesellschaft Drum with a body with toxic and/or radioactive contamination and production process of said drum
GB2331106A (en) * 1997-11-05 1999-05-12 Polyval Plc Use of polyvinyl alcohol as rust remover
US20040149311A1 (en) * 2002-11-15 2004-08-05 The Procter & Gamble Company Method for cleaning cookware and tableware with film-forming liquid dishwashing compositions, and compositions therefore
WO2005031757A1 (en) * 2003-09-23 2005-04-07 Microtek Medical Holdings, Inc. Strippable pva coatings and methods of making and using the same
DE102005037335B4 (en) * 2005-08-04 2008-12-11 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Residue-free removable pickling agent
RU2520446C2 (en) * 2012-10-15 2014-06-27 Открытое акционерное общество "Научно-производственное объединение по исследованию и проектированию энергетического оборудования им. И.И. Ползунова" (ОАО "НПО ЦКТИ") Method of cleaning of energotechnological equipment working surfaces
RU2638162C1 (en) * 2017-03-06 2017-12-12 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" Composition for dust suppression and containment of combustion products after fire extinguishing with radiation factor
DE102020120666B3 (en) * 2020-04-30 2021-02-04 Kompass Holding GbR Marc Schulte & Miriam Schulte (vertretungsberechtigter Gesellschafter: Miriam Schulte, 33739 Bielefeld) Method for removing a large area of a contaminated plastic coating from a building made of concrete or masonry
CN115926515A (en) * 2022-12-06 2023-04-07 核工业北京化工冶金研究院 Strippable membrane detergent and application method thereof

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GB848588A (en) * 1959-06-05 1960-09-21 Atomic Energy Authority Uk Method for separating particles of radioactive material from a solid surface
BE607242A (en) * 1960-08-16
DD81048A1 (en) * 1969-09-22 1971-04-05 Method for decontaminating surfaces using peelable layers
EP0047857A3 (en) * 1980-09-13 1982-06-23 Nukem GmbH Process for decontaminating radioactively polluted surfaces
DE3103353A1 (en) * 1981-01-31 1982-08-12 Nukem Gmbh, 6450 Hanau Process for the decontamination of radioactively contaminated surfaces
DE3172473D1 (en) * 1981-03-18 1985-11-07 Wiederaufarbeitung Von Kernbre Process for decontaminating objects

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DE3446931C2 (en) 1987-01-08
DE3560971D1 (en) 1987-12-17
ATE30804T1 (en) 1987-11-15
DE3446931A1 (en) 1986-07-03

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