EP1082728B1 - Method for reducing the level of radioactivity of a metal part - Google Patents

Method for reducing the level of radioactivity of a metal part Download PDF

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Publication number
EP1082728B1
EP1082728B1 EP99927700A EP99927700A EP1082728B1 EP 1082728 B1 EP1082728 B1 EP 1082728B1 EP 99927700 A EP99927700 A EP 99927700A EP 99927700 A EP99927700 A EP 99927700A EP 1082728 B1 EP1082728 B1 EP 1082728B1
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Prior art keywords
agents
metal
decontamination solution
oxidizing
decontamination
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German (de)
French (fr)
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EP1082728A1 (en
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Horst-Otto Bertholdt
Rainer Gassen
Franz Strohmer
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Areva GmbH
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Framatome ANP GmbH
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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
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof
    • G21F9/002—Decontamination of the surface of objects with chemical or electrochemical processes
    • G21F9/004—Decontamination of the surface of objects with chemical or electrochemical processes of metallic surfaces

Definitions

  • the invention relates to a method for reducing radioactivity of a metal part, with a decontamination solution an oxide layer is removed from the metal part.
  • a process for the chemical decontamination of surfaces metallic components of nuclear reactor plants is for example known from EP 0 355 628 B1.
  • the goal of such The procedure is to remove the surface of metallic components from a rid radioactive contaminated oxide layer.
  • the z.3. Contains oxalic acid or another carboxylic acid.
  • radionuclides are mainly stored in the oxidic Protective layers that are metallic on the surfaces Components.
  • oxidic Protective layers that are metallic on the surfaces Components.
  • decontamination work during a normal revision of a nuclear power plant consequently removing the oxide layer.
  • suitable decontamination solution selected so that the Base metal of the components is not attacked.
  • the invention was based on the object of specifying a method with which it is possible to contaminate radioactive metal rid of radionuclides so far that it is considered inactive Scrap can be fed into the usual material cycle.
  • the redox potential in the decontamination solution becomes average lowered and there is also the corrosion potential of the base metal reduced. As a result, an attack on the base metal is made specifically. Doing some Micrometer of the base metal removed.
  • the advantage of the method according to the invention is achieved, that the targeted base metal attack the radionuclides be separated from the metal. It advantageously remains Metal scrap, which is, as usual, inactive scrap can be treated further. On the other hand, no more Base metal removed as necessary, so that little waste one Repository must be supplied.
  • Agents having an oxidizing action and which are removed from the decontamination solution are, for example, Fe 3+ and / or residual oxygen.
  • the oxidizing Fe 3+ comes from the oxide layer, which was detached from the metal surface in a previous decontamination step.
  • a reducing agent for example, is added to the decontamination solution.
  • the interfering Fe 3+ can be converted into non-interfering Fe 2+ .
  • This reducing agent can be ascorbic acid.
  • the decontamination solution can also be used with a Be gassed with inert gas. This will make the one that still exists Residual oxygen expelled.
  • a suitable inert gas is, for example Nitrogen.
  • the decontamination solution is irradiated with UV light in order to remove oxidizing agents.
  • the disruptive Fe 3+ and existing organic decontamination acid produce Fe 2+ and carbon dioxide when exposed to UV radiation.
  • the Fe 2+ formed in this way and the organic decontamination acid present then form Fe 3+ and carbon dioxide together with the disturbing residual oxygen when exposed to UV radiation. This reaction continues until there is no more oxygen.
  • the Fe 3+ formed is then converted into Fe 2+ and carbon dioxide after the first-mentioned reaction, so that only these two substances and no oxidizing agents are left.
  • Fe 2+ ions that are formed are removed with a cation exchanger.
  • a cation exchanger advantageously has a very large capacity. So you can get by with a small ion exchanger.
  • an anion exchanger would be required, since Fe 3+ forms organic complexes with organic decontamination acids, for example an oxalato complex, the capacity of which is significantly smaller than that of a cation exchanger.
  • the conversion of Fe 3+ into Fe 2+ also has the advantage that the remaining decontamination solution to be disposed of does not contain any chelates (complexes) which would have to be removed in a complex manner.
  • the decontamination solution can be used to improve the removal of base metal additionally nitric acid, e.g. in a concentration from 100 ppm to 10000 ppm can be added to the solution.
  • the removal process becomes oxidizing active agents not continued until no oxidizing agents Means more are available. This will be removing stopped, for example, by adding an oxidizing agent.
  • the oxidizing agent can e.g. Air, oxygen, iron (3) ions, Be hydrogen peroxide and / or ozone.
  • the base metal attack can be special advantageously only the exact amount of metal is removed, the radionuclides present in the near-surface area contains.
  • the treatment time and also the amount of waste to be disposed of, which is sent to a repository must be greatly minimized.
  • the basic metal removal can by alternating triggering and stopping in single Steps of up to a tenth of a micron can be controlled. Depending on requirements, up to several 100 micrometers can then be used or less.
  • the drawing shows the course of the corrosion potential of a metal part from triggering the removal oxidizing active agent from the decontamination solution until stopping of the process.
  • the lower curve shows the Base metal attack.
  • Period A During a normal decontamination process without attacking the base metal (Period A) is the corrosion potential about 200 mV. During this period A there is almost no base metal attack instead of what is a common decontamination process is also not desired.
  • Period B takes place a UV treatment, so that the corrosion potential drops to about -300 mV and the base metal attack rises slowly and then very quickly.
  • the desired base metal attack takes place in the following period C. instead, which contains at least some of the radionuclides Layer of the metal part is removed.
  • Period D becomes the base metal attack by adding Hydrogen peroxide stopped. The corrosion potential increases back to a value of almost 200 mV and the base metal attack goes back to a negligible value.
  • Period E can passivate the base metal respectively. But it can also be determined whether enough metal has been removed. The described procedure can join several times if necessary until the remaining one Metal is free of radionuclides and a common one Scrapping can be fed.

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  • Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Apparatus For Disinfection Or Sterilisation (AREA)
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Description

Die Erfindung betrifft ein Verfahren zum Abbau der Radioaktivität eines Metallteiles, wobei mit einer Dekontaminationslösung eine Oxidschicht vom Metallteil entfernt wird.The invention relates to a method for reducing radioactivity of a metal part, with a decontamination solution an oxide layer is removed from the metal part.

Ein Verfahren zur chemischen Dekontamination von Oberflächen metallischer Bauteile von Kernreaktoranlagen ist beispielsweise aus der EP 0 355 628 B1 bekannt. Das Ziel eines solchen Verfahrens ist, die Oberfläche metallischer Bauteile von einer radioaktiv kontaminierten Oxidschicht zu befreien. Dazu kann als Dekontaminationslösung eine Lösung verwendet werden, die z.3. Oxalsäure oder eine andere Carbonsäure enthält.A process for the chemical decontamination of surfaces metallic components of nuclear reactor plants is for example known from EP 0 355 628 B1. The goal of such The procedure is to remove the surface of metallic components from a rid radioactive contaminated oxide layer. To a solution can be used as a decontamination solution, the z.3. Contains oxalic acid or another carboxylic acid.

Während des langjährigen Leistungsbetriebes eines Kernkraftwerkes lagern sich Radionuklide hauptsächlich in die oxidischen Schutzschichten ein, die sich auf den Oberflächen metallischer Bauteile befinden. Für Dekontaminationsarbeiten während einer üblichen Revision eines Kernkraftwerkes reicht folglich ein Entfernen der Oxidschicht aus. Dabei wird eine geeignete Dekontaminationslösung so ausgewählt, daß das Grundmetall der Bauteile nicht angegriffen wird.During the long-term performance of a nuclear power plant radionuclides are mainly stored in the oxidic Protective layers that are metallic on the surfaces Components. For decontamination work during a normal revision of a nuclear power plant consequently removing the oxide layer. Doing so suitable decontamination solution selected so that the Base metal of the components is not attacked.

Dieses Vorgehen ist bei einer Revision sinnvoll, da sich ca. 98 % der Radionuklide in der Oxidschicht befinden. Nur ca. 2 % der Radionuklide gelangen durch Diffusion in Oberflächennahe Bereiche des Grundmetalls, aus dem die Bauteile bestehen.This procedure makes sense for a revision because approx. 98% of the radionuclides are in the oxide layer. Only approx 2% of the radionuclides reach the surface by diffusion Areas of the base metal that make up the components.

Bei einem Austausch von Komponenten eines Kernkraftwerkes oder bei einer Stillegung führen die ca. 2 % der Radionuklide, die sich durch Diffusion im Oberflächenbereich des Grundmetalls befinden, dazu, daß das Metall auch nach einer Dekontamination in ein Endlager verbracht werden muß. When replacing components of a nuclear power plant or in the case of decommissioning, the approx. 2% of the radionuclides diffusion in the surface area of the Base metal, that the metal even after a Decontamination must be brought to a repository.

Da sehr große Metallmengen anfallen, wäre ein sehr großes Endlager notwendig, das nicht wirtschaftlich ist.Since there are very large amounts of metal, this would be a very large one Repository necessary, which is not economical.

Der Erfindung lag die Aufgabe zugrunde, ein Verfahren anzugeben, mit dem es möglich ist, radioaktiv kontaminiertes Metall so weit von Radionukliden zu befreien, daß es als inaktiver Schrott dem üblichen Materialkreislauf zugeführt werden kann.The invention was based on the object of specifying a method with which it is possible to contaminate radioactive metal rid of radionuclides so far that it is considered inactive Scrap can be fed into the usual material cycle.

Die Aufgabe wird gemäß Anspruch 1 gelöst.The object is achieved according to claim 1.

Durch das Entfernen eines oder mehrerer oxidierend wirkender Mittel wird das Redoxpotential in der Dekontaminationslösung abgesenkt und es wird auch das Korrosionspotential des Grundmetalls vermindert. Das hat zur Folge, daß ein Angriff auf das Grundmetall gezielt vorgenommen wird. Dabei werden einige Mikrometer des Grundmetalls abgetragen.By removing one or more oxidizing The redox potential in the decontamination solution becomes average lowered and there is also the corrosion potential of the base metal reduced. As a result, an attack on the base metal is made specifically. Doing some Micrometer of the base metal removed.

Da sich die durch Diffusion in das Metall gelangten Radionuklide nur in oberflächennahen Bereichen des Metalls befinden, wird mit dem Verfahren nach der Erfindung der Vorteil erzielt, daß durch den gezielten Grundmetallangriff die Radionuklide vom Metall abgetrennt werden. Es verbleibt vorteilhafterweise Metallschrott, der wie üblicher inaktiver Schrott weiterbehandelt werden kann. Andererseits wird nicht mehr Grundmetall als nötig abgetragen, so daß nur wenig Abfall einem Endlager zugeführt werden muß.Because the radionuclides that got into the metal by diffusion only in areas of the metal near the surface, the advantage of the method according to the invention is achieved, that the targeted base metal attack the radionuclides be separated from the metal. It advantageously remains Metal scrap, which is, as usual, inactive scrap can be treated further. On the other hand, no more Base metal removed as necessary, so that little waste one Repository must be supplied.

Oxidierend wirkende Mittel, die aus der Dekontaminationslösung entfernt werden, sind beispielsweise Fe3+ und/oder Restsauerstoff. Das oxidierend wirkende Fe3+ stammt dabei aus der Oxidschicht, die in einem vorangegangenen Dekontaminationsschritt von der Metalloberfläche abgelöst worden ist. Agents having an oxidizing action and which are removed from the decontamination solution are, for example, Fe 3+ and / or residual oxygen. The oxidizing Fe 3+ comes from the oxide layer, which was detached from the metal surface in a previous decontamination step.

Zum Entfernen oxidierend wirkender Mittel wird der Dekontaminationslösung beispielsweise ein Reduktionsmittel zugegeben. Mit einem solchen Reduktionsmittel kann das störende Fe3+ in nicht störendes Fe2+ umgewandelt werden. Dieses Reduktionsmittel kann Ascorbinsäure sein.To remove oxidizing agents, a reducing agent, for example, is added to the decontamination solution. With such a reducing agent, the interfering Fe 3+ can be converted into non-interfering Fe 2+ . This reducing agent can be ascorbic acid.

Zum Entfernen oxidierend wirkender Mittel, die in der Regel Gase sind, kann die Dekontaminationslösung auch mit einem Inertgas begast werden. Dadurch wird der noch vorhandene Restsauerstoff ausgetrieben. Ein geeignetes Inertgas ist beispielsweise Stickstoff.To remove oxidizing agents, as a rule Are gases, the decontamination solution can also be used with a Be gassed with inert gas. This will make the one that still exists Residual oxygen expelled. A suitable inert gas is, for example Nitrogen.

Nach einer besonders vorteilhaften Weiterbildung des Verfahrens wird die Dekontaminationslösung zum Entfernen oxidierend wirkender Mittel mit UV-Licht bestrahlt. Damit wird der Vorteil erzielt, daß mit Hilfe einer organischen Dekontaminationssäure, die aufgrund des vorangegangenen Dekontaminationsschrittes noch in der Dekontaminationslösung vorhanden ist, sowohl störendes Fe3+ als auch störender Restsauerstoff entfernt werden können.According to a particularly advantageous development of the method, the decontamination solution is irradiated with UV light in order to remove oxidizing agents. This has the advantage that with the help of an organic decontamination acid, which is still present in the decontamination solution due to the previous decontamination step, both disturbing Fe 3+ and disturbing residual oxygen can be removed.

Aus dem störenden Fe3+ und vorhandener organischer Dekontaminationssäure entstehen bei UV-Bestrahlung Fe2+ und Kohlenstoffdioxid. Das so gebildete Fe2+ und vorhandene organische Dekontaminationssäure bilden bei UV-Bestrahlung zusammen mit dem störenden Restsauerstoff dann Fe3+ und Kohlenstoffioxid. Diese Reaktion läuft solange ab, bis kein Sauerstoff mehr vorhanden ist. Das entstandene Fe3+ wird dann nach der zuerstgenannten Reaktion in Fe2+ und Kohlenstoffdioxid umgewandelt, so daß nur noch diese beiden Stoffe und keine oxidierend wirkenden Mittel mehr vorhanden sind.The disruptive Fe 3+ and existing organic decontamination acid produce Fe 2+ and carbon dioxide when exposed to UV radiation. The Fe 2+ formed in this way and the organic decontamination acid present then form Fe 3+ and carbon dioxide together with the disturbing residual oxygen when exposed to UV radiation. This reaction continues until there is no more oxygen. The Fe 3+ formed is then converted into Fe 2+ and carbon dioxide after the first-mentioned reaction, so that only these two substances and no oxidizing agents are left.

Beispielsweise werden entstehende Fe2+-Ionen mit einem Kationenaustauscher entfernt. Ein Kationenaustauscher hat vorteilhafterweise eine sehr große Kapazität. Man kommt also mit einem kleinen Ionenaustauscher aus. Bei einer direkten Entfernung von Fe3+-Ionen wäre namlich, da Fe3+ mit organischen Dekontaminationssäuren organische Komplexe bildet, z.B. einen Oxalatokomplex, ein Anionenaustauscher erforderlich, dessen Kapazität deutlich kleiner als die eines Kationenaustauschers ist.For example, Fe 2+ ions that are formed are removed with a cation exchanger. A cation exchanger advantageously has a very large capacity. So you can get by with a small ion exchanger. In the case of direct removal of Fe 3+ ions, an anion exchanger would be required, since Fe 3+ forms organic complexes with organic decontamination acids, for example an oxalato complex, the capacity of which is significantly smaller than that of a cation exchanger.

Durch die Umwandlung von Fe3+ in Fe2+ wird darüber hinaus der Vorteil erzielt, daß die verbleibende zu entsorgende Dekontaminationslösung keine Chelate (Komplexe) enthält, die aufwendig beseitigt werden müßten.The conversion of Fe 3+ into Fe 2+ also has the advantage that the remaining decontamination solution to be disposed of does not contain any chelates (complexes) which would have to be removed in a complex manner.

Zum Verbessern des Grundmetallabtrags kann der Dekontaminationslösung zusätzlich Salpetersäure, z.B. in einer Konzentration von 100 ppm bis 10000 ppm in der Lösung zugegeben werden.The decontamination solution can be used to improve the removal of base metal additionally nitric acid, e.g. in a concentration from 100 ppm to 10000 ppm can be added to the solution.

Beispielsweise wird das Verfahren zum Entfernen oxidierend wirkender Mittel nicht fortgeführt, bis keine oxidierend wirkende Mittel mehr vorhanden sind. Dazu wird das Entfernen beispielsweise durch Zugabe eines Oxidationsmittels gestoppt. Das Oxidationsmittel kann z.B. Luft, Sauerstoff, Eisen (3)-Ionen, Wasserstoffperoxid und/oder Ozon sein.For example, the removal process becomes oxidizing active agents not continued until no oxidizing agents Means more are available. This will be removing stopped, for example, by adding an oxidizing agent. The oxidizing agent can e.g. Air, oxygen, iron (3) ions, Be hydrogen peroxide and / or ozone.

Mit dem Stoppen des Entfernens oxidierend wirkender Mittel wird der Vorteil erzielt, daß man nur eine gewünschte sehr dünne Schicht vom Grundmetall abtragen kann. Es hat sich nämlich herausgestellt, daß die Radionuklide nur bis zur Tiefe von einigen 10 Mikrometer in das Grundmetall durch Diffusion, d.h. durch den Austausch von Gitterplätzen im Metallgitter, eindringen.By stopping the removal of oxidizing agents the advantage is achieved that you only a desired very can remove a thin layer from the base metal. Because it has found that the radionuclides only to the deep of some 10 microns into the base metal by diffusion, i.e. by exchanging lattice sites in the metal lattice, penetration.

Beispielsweise wird das Entfernen oxidierend wirkender Mittel aus der Dekontaminationslösung in zeitlichen Wechsel ausgelöst und gestoppt. Mit einem möglichst schnellen Wechsel von Auslösen und Stoppen des Grundmetallangriffs kann besonders vorteilhaft exakt nur diejenige Metallmenge entfernt werden, die die im oberflächennahen Bereich vorhandenen Radionuklide enthält. Vorteilhafterweise werden die Behandlungszeit und auch die zu entsorgende Abfallmenge, die einem Endlager zugeführt werden muß, stark minimiert. Der Grundmetallabtrag kann durch den Wechsel von Auslösen und Stoppen in einzelnen Schritten von bis zu einem Zehntel Mikrometer gesteuert werden. Je nach Erfordernis können dann bis zu mehreren 100 Mikrometer oder auch weniger abgetragen werden.For example, removing oxidizing agents triggered from the decontamination solution in alternating times and stopped. With a change from Triggering and stopping the base metal attack can be special advantageously only the exact amount of metal is removed, the radionuclides present in the near-surface area contains. The treatment time and also the amount of waste to be disposed of, which is sent to a repository must be greatly minimized. The basic metal removal can by alternating triggering and stopping in single Steps of up to a tenth of a micron can be controlled. Depending on requirements, up to several 100 micrometers can then be used or less.

Mit dem Verfahren nach der Erfindung wird insbesondere der Vorteil erzielt, daß radioaktiv kontaminierte Metallteile nach der Behandlung als nicht kontaminierter Schrott einer üblichen Verwertung zugeführt werden können und nicht in einem Endlager gelagert werden müssen.With the method according to the invention, in particular Advantage achieved that radioactive contaminated metal parts after treatment as uncontaminated scrap one usual recycling can be supplied and not in one Repository must be stored.

Das Verfahren zum Abbau der Radioaktivität eines Metallteiles wird anhand der Zeichnung näher erläutert:The process of reducing the radioactivity of a metal part is explained in more detail using the drawing:

Die Zeichnung zeigt oben den Verlauf des Korrosionspotentials eines Metallteiles vom Auslösen der Entfernung oxidierend wirkender Mittel aus der Dekontaminationslösung bis zum Stoppen des Vorganges. Die untere Kurve zeigt zeitgleich den Grundmetallangriff.The drawing shows the course of the corrosion potential of a metal part from triggering the removal oxidizing active agent from the decontamination solution until stopping of the process. The lower curve shows the Base metal attack.

Während eines üblichen Dekontaminationsverfahrens ohne Grundmetallangriff (Zeitraum A) beträgt das Korrosionspotential ungefähr 200 mV. In diesem Zeitraum A findet fast kein Grundmetallangriff statt, was bei einem üblichen Dekontaminationsverfahren auch nicht gewünscht ist. Im anschließenden Zeitraum B findet eine UV-Behandlung statt, so daß das Korrosionspotential auf ungefähr -300 mV abfällt und der Grundmetallangriff erst langsam und dann sehr schnell ansteigt. Im folgenden Zeitraum C findet der gewünschte Grundmetallangriff statt, wodurch zumindest ein Teil der Radionuklide enthaltenden Schicht des Metallteiles entfernt wird. Im anschließenden Zeitraum D wird der Grundmetallangriff durch die Zugabe von Wasserstoffperoxid gestoppt. Das Korrosionspotential steigt wieder auf einen Wert von fast 200 mV an und der Grundmetallangriff geht zurück auf einen vernachlässigbaren Wert. Im anschließenden Zeitraum E kann eine Passivierung des Grundmetalls erfolgen. Es kann aber dann auch festgestellt werden, ob genügend Metall abgetragen ist. Das geschilderte Verfahren kann sich bei Bedarf noch mehrmals anschließen bis das verbleibende Metall von Radionukliden frei ist und einer üblichen Verschrottung zugeführt werden kann.During a normal decontamination process without attacking the base metal (Period A) is the corrosion potential about 200 mV. During this period A there is almost no base metal attack instead of what is a common decontamination process is also not desired. In the subsequent period B takes place a UV treatment, so that the corrosion potential drops to about -300 mV and the base metal attack rises slowly and then very quickly. in the The desired base metal attack takes place in the following period C. instead, which contains at least some of the radionuclides Layer of the metal part is removed. In the following Period D becomes the base metal attack by adding Hydrogen peroxide stopped. The corrosion potential increases back to a value of almost 200 mV and the base metal attack goes back to a negligible value. in the subsequent period E can passivate the base metal respectively. But it can also be determined whether enough metal has been removed. The described procedure can join several times if necessary until the remaining one Metal is free of radionuclides and a common one Scrapping can be fed.

Claims (11)

  1. Method for reducing the radioactivity of a metal part, in which an oxide layer is removed from the metal part using a decontamination solution, characterized in that as a result of one or more agents which have an oxidizing action being removed from the decontamination solution, the redox potential of this solution is lowered and the corrosion potential of the metal of which the metal part consists is reduced, and as a result a layer of the metal is removed.
  2. Method according to Claim 1, characterized in that agents which have an oxidizing action are Fe3+ and/or residual oxygen.
  3. Method according to either of Claims 1 and 2, characterized in that a reducing agent is added to the decontamination solution in order to remove agents which have an oxidizing action.
  4. Method according to Claim 3, characterized in that the reducing agent is ascorbic acid.
  5. Method according to one of Claims 1 to 4, characterized in that an inert gas is passed through the decontamination solution in order to remove agents which have an oxidizing action.
  6. Method according to one of Claims 1 to 5, characterized in that the decontamination solution is irradiated with UV light in order to remove agents which have an oxidizing action.
  7. Method according to one of Claims 3 to 6, characterized in that Fe2+ ions which form are removed using a cation exchanger.
  8. Method according to one of Claims 1 to 7, characterized in that nitric acid is added to the decontamination solution.
  9. Method according to one of Claims 1 to 8, characterized in that the removal of agents which have an oxidizing action is stopped by the addition of an oxidizing agent.
  10. Method according to Claim 9, characterized in that the oxidizing agent is air, oxygen, iron(3) ions, hydrogen peroxide and/or ozone.
  11. Method according to either of Claims 9 and 10, characterized in that the removal of agents which have an oxidizing action is initiated and stopped in an alternating sequence.
EP99927700A 1998-04-27 1999-04-21 Method for reducing the level of radioactivity of a metal part Expired - Lifetime EP1082728B1 (en)

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DE19818772 1998-04-27
DE19818772A DE19818772C2 (en) 1998-04-27 1998-04-27 Process for reducing the radioactivity of a metal part
PCT/DE1999/001203 WO1999056286A2 (en) 1998-04-27 1999-04-21 Method for reducing the level of radioactivity of a metal part

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EP1082728A1 EP1082728A1 (en) 2001-03-14
EP1082728B1 true EP1082728B1 (en) 2002-08-07

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US (1) US6613153B1 (en)
EP (1) EP1082728B1 (en)
JP (1) JP3881515B2 (en)
KR (1) KR100446810B1 (en)
AR (1) AR016220A1 (en)
BR (1) BR9909968B1 (en)
CA (1) CA2329814C (en)
DE (2) DE19818772C2 (en)
ES (1) ES2180306T3 (en)
MX (1) MXPA00010614A (en)
TW (1) TW418404B (en)
WO (1) WO1999056286A2 (en)

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WO2013041595A1 (en) 2011-09-20 2013-03-28 Nis Ingenieurgesellschaft Mbh Method for decomposing an oxide layer
DE102012023938A1 (en) 2012-12-06 2014-06-12 Kathrein-Werke Kg Dual polarized omnidirectional antenna
DE102013102331B3 (en) * 2013-03-08 2014-07-03 Horst-Otto Bertholdt Process for breaking down an oxide layer
WO2018149862A1 (en) 2017-02-14 2018-08-23 Siempelkamp NIS Ingenieurgesellschaft mbH Method for decomposing a radionuclide-containing oxide layer

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KR100724710B1 (en) * 2002-11-21 2007-06-04 가부시끼가이샤 도시바 System and method for chemical decontamination of radioactive material
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TW418404B (en) 2001-01-11
EP1082728A1 (en) 2001-03-14
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CA2329814A1 (en) 1999-11-04

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