WO1984003170A1 - Decontamination de reacteurs a eau sous pression - Google Patents

Decontamination de reacteurs a eau sous pression Download PDF

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Publication number
WO1984003170A1
WO1984003170A1 PCT/SE1984/000012 SE8400012W WO8403170A1 WO 1984003170 A1 WO1984003170 A1 WO 1984003170A1 SE 8400012 W SE8400012 W SE 8400012W WO 8403170 A1 WO8403170 A1 WO 8403170A1
Authority
WO
WIPO (PCT)
Prior art keywords
acid
oxidation
permanganate
ozone
decontamination
Prior art date
Application number
PCT/SE1984/000012
Other languages
English (en)
Inventor
Jan Arvesen
Hans-Peter Hermansson
Original Assignee
Studsvik Energiteknik Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Studsvik Energiteknik Ab filed Critical Studsvik Energiteknik Ab
Publication of WO1984003170A1 publication Critical patent/WO1984003170A1/fr

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Classifications

    • 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
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof
    • G21F9/002—Decontamination of the surface of objects with chemical or electrochemical processes
    • G21F9/004—Decontamination of the surface of objects with chemical or electrochemical processes of metallic surfaces

Definitions

  • the present invention relates to a method by which radi active coatings on the walls of the primary heating system in nuclear reactors of the pressurized water type can be removed More specifically, the invention relates to the decontaminat ⁇ ion of in acid insoluble or sparingly soluble corrosion pro ⁇ ducts from these primary system surfaces.
  • the invention is a development of the technique that includes a first step wherein the contaminated surfaces are contacted with an oxidation agent, for oxidation of the insoluble pro ⁇ ducts to acid-soluble oxidation products, whereupon in a sub ⁇ sequent step the oxidized products are dissolved and removed by means of an acidic decontamination solution.
  • the corrosion products which are now radioactive after the neutron irradiation, are liberated from the fuel elements and are subsequently deposited on the parts of the primary system in contact with water which lie outside the reactor core. Then the radioactive corrosion products giv rise to radiation fields outside the core and thereby to radiation doses to the operational personnel.
  • the decontaminat ion factor (Df) is defined in the following way:
  • R OM the APAC process is the large volumes of waste occurring in the form of radioactive ion exchangemasses or evaporator residues .
  • ox dizing agents permanganate in an alkaline or nitric acidic environ ⁇ ment (in the latter case the pH is about 2.5) - potassium hexacyanoferrate in an alkaline environment
  • organic acids citric or oxalic acids and ammoniu salts of these
  • EDTA ethylenediaminetetraaceticacid
  • Additives in the form of reducing agents such as aldehydes or ascorbic acid can also be present in the acid treatment step.
  • OMPI pre-treatment in an oxidizing environment.
  • the completely dominating oxidation agent in this respect is permanganate.
  • the reaction sequence for the oxidation step is substantially as follows: 3Mn0 ⁇ + Cr 3+ + 8H 2 0 "* ⁇ * ⁇ 3Mn 2+ + 5Cr0 4 2" + 16H +
  • the method according to the invention more specifically involves the utilization of the combination of permanganate, chromic acid and ozone as oxidation agent in the introductory oxidation step.
  • this combination has been found to give a synergistic effect which could not be predicted against the background of the known properties of these oxidation agents taken individually.
  • the contami ⁇ nated surfaces are brought into contact with the above-mentio ned oxidation agent in an aqueously based form and with an acidic pH, i.e. a pH be-low 7 .
  • an acidic pH i.e. a pH be-low 7 .
  • the oxidation agent is present in the form of an aqueous solution of permanganate and chromic acid, and ozone prefe ⁇ rably in a saturated solution and dispersed form.
  • the oxidation agen can however be utilized in the form of a two-phase ozone gas- -water mixture, where ozone in gaseous form is dispersed in water with added permanganate and chromic acid.
  • ozone in gaseous form is dispersed in water with added permanganate and chromic acid.
  • a particularly pre ⁇ ferable embodiment of the method in accordance with the inven ion thus means that the oxidation step or the acid dissolving step or preferably both these steps are carried out at room temperature or lower, i.e. at a temperature below about 25 C and preferably below about 20 C.
  • the oxidation step according to the invention means tha the contaminated surfaces are contacted with the new oxidatio agent for a sufficient period of time to oxidize insoluble oxi ⁇ des, so as to make these soluble in the acidic decontaminatio solutions used in subsequent steps.
  • the period of time requir ed in each individual case is of course easily determined by one skilled in the art against the background of utilized concentrations of oxidation reagents as well as subsequent acid solutions, utilized treatment temperatures etc.
  • the choice of permanganate is made according to the prior art, i.e.
  • the permanganate is preferably an alkali meta permanganate and particularly potassium permanganate.
  • the origin of the chromic acid is preferably dosed chromium tri- oxide, and the ozone is suitably utilized in the form of an ozone-enriched oxygen gas or air.
  • concentrations or proportions of the chemicals in ⁇ cluded in the oxidation agent are determined by one skilled in the art from case to case, so as to obtain the desired results, inter alia depending on the materials which are to be decontaminated and the desired decontamination effect, but generally the concentrations are usually within the range of 0.01-50 g/1, preferably 0.5-2 g/1, of the permanganate, with ⁇ in the range of 0.01-50 g/1, preferably 0.05-0.2 g/1, of the chromic acid and within the range of 0.001-1 g/1, preferably 0.005-0.015 g/1 of the ozone.
  • the water-based or aqueous oxidation agent ' has prefer ⁇ ably been made acidic by nitric acid or an aliphatic satur- ated monobasic carboxylic acid, suitably to a pH of about 3, an example of the latter type of acid being acetic acid.
  • the concentration of the acid used in the acid dissolving step can be kept low in accordance with the presen invention, even in spite of the fact that the temperature is about or below room temperature, the type of acid is selected in accordance with the prior art.
  • citric acid and oxalic acid can thus be mentioned.
  • the method in accordance with the invention is generall utilizable for the decontamination of all those different types of materials which are present in these connections.
  • the invention has been found to give extremely good results in the decontamination of chromium (III) oxide from a chromium-nickel-iron alloy, such a decontamination there- fore representing an especially preferable embodiment of the invention.
  • the second step treatment was carried out in an aqueous solution containing 12 g/1 of boric acid and solely citric acid in an amount of about 2 g/1 at a pH of 3,5 (adjusted with NH,) and room temperature (about 20 C) for 6 hours.
  • the three samples were exposed in parallel in a 100 ml glass container in an aqueous solution containing 12 g/1 of boric acid, 1.0 g/1 of KMn0 4 and 0.2 g/1 of Cr0 3 in 1% acetic acid at a pH of about 3.
  • Oxygen gas with about 2.5 percent by volume of ozone was bubbled into the same container at a rate of about 0.1 1/min.
  • the temperature was 20 C and the exposure time was 21 . hours.
  • the corrosion .test was terminated after a subsequent • exposure of up to 6 hours to an oxygen-free 2 % citric acid solution at 20 C and a pH of about 3.
  • Exposure times oxidizing step time hours reducing step time ho.urs 1a 23 2a 6

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Detergent Compositions (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Apparatus For Disinfection Or Sterilisation (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)

Abstract

Procédé de décontamination de produits de corrosion contaminés par des nucléides radioactifs et insolubles dans un acide, provenant des surfaces d'un système primaire dans des réacteurs à eau sous pression par oxydation et dissolution ultérieure dans une solution acide de décontamination des produits de corrosion qui ont été rendus solubles dans un acide par l'oxydation. Le procédé se caractérise par le fait que l'oxydation est exécutée à l'aide d'un agent d'oxydation à base aqueuse possédant un pH inférieur à 7 et contenant du permanganate, de l'acide chromique et de l'ozone. Dans un mode préférentiel de réalisation du procédé, l'oxydation est exécutée à une température relativement faible, par exemple en dessous de 60oC environ et souvent en dessous de 25oC environ.
PCT/SE1984/000012 1983-02-09 1984-01-17 Decontamination de reacteurs a eau sous pression WO1984003170A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE8300685A SE435329B (sv) 1983-02-09 1983-02-09 Dekontaminering av tryckvattenreaktorer

Publications (1)

Publication Number Publication Date
WO1984003170A1 true WO1984003170A1 (fr) 1984-08-16

Family

ID=20349962

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1984/000012 WO1984003170A1 (fr) 1983-02-09 1984-01-17 Decontamination de reacteurs a eau sous pression

Country Status (5)

Country Link
EP (1) EP0137002A1 (fr)
KR (1) KR840007798A (fr)
ES (1) ES8604701A1 (fr)
SE (1) SE435329B (fr)
WO (1) WO1984003170A1 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0180826A1 (fr) * 1984-10-31 1986-05-14 Siemens Aktiengesellschaft Procédé pour décontaminer chimiquement les composants importants et les système métalliques des réacteurs nucléaires
US4704235A (en) * 1984-03-09 1987-11-03 Studsvik Energiteknik Ab Decontamination of pressurized water reactors
FR2600203A1 (fr) * 1986-06-17 1987-12-18 Lemmens Godfried Procede pour la decontamination des materiaux a contamination radioactive
WO1989003113A1 (fr) * 1987-10-02 1989-04-06 Abb Reaktor Gmbh Procede de decontamination de surfaces
US4913849A (en) * 1988-07-07 1990-04-03 Aamir Husain Process for pretreatment of chromium-rich oxide surfaces prior to decontamination
FR2648946A1 (fr) * 1989-06-27 1990-12-28 Electricite De France Procede de dissolution d'oxyde depose sur un substrat metallique et son application a la decontamination
EP0727243A1 (fr) * 1995-02-20 1996-08-21 Commissariat A L'energie Atomique Mousse de décontamination à l'ozone, et procédé de décontamination utilisant cette mousse
EP1220233A2 (fr) * 2000-12-21 2002-07-03 Kabushiki Kaisha Toshiba Procédé de décontamination chimique ainsi que procédé et appareil pour le traitement de la solution de décontamination chimique
JP2002250794A (ja) * 2000-12-21 2002-09-06 Toshiba Corp 化学除染方法
US6875323B2 (en) * 1998-06-23 2005-04-05 Kabushiki Kaisha Toshiba Method of chemically decontaminating components of radioactive material handling facility and system for carrying out the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2358683A1 (de) * 1973-11-24 1975-06-05 Kalman Von Dipl Phys Soos Verfahren zum beizen und aetzen von metallen
US4287002A (en) * 1979-04-09 1981-09-01 Atomic Energy Of Canada Ltd. Nuclear reactor decontamination

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2358683A1 (de) * 1973-11-24 1975-06-05 Kalman Von Dipl Phys Soos Verfahren zum beizen und aetzen von metallen
US4287002A (en) * 1979-04-09 1981-09-01 Atomic Energy Of Canada Ltd. Nuclear reactor decontamination

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4704235A (en) * 1984-03-09 1987-11-03 Studsvik Energiteknik Ab Decontamination of pressurized water reactors
EP0180826A1 (fr) * 1984-10-31 1986-05-14 Siemens Aktiengesellschaft Procédé pour décontaminer chimiquement les composants importants et les système métalliques des réacteurs nucléaires
US4942594A (en) * 1984-10-31 1990-07-17 Siemens Aktiengesellschaft Method for the chemical decontamination of large components and systems of metallic materials of nuclear reactors
FR2600203A1 (fr) * 1986-06-17 1987-12-18 Lemmens Godfried Procede pour la decontamination des materiaux a contamination radioactive
WO1989003113A1 (fr) * 1987-10-02 1989-04-06 Abb Reaktor Gmbh Procede de decontamination de surfaces
EP0313843A1 (fr) * 1987-10-02 1989-05-03 ABB Reaktor GmbH Procédé pour décontaminer des surfaces
US4913849A (en) * 1988-07-07 1990-04-03 Aamir Husain Process for pretreatment of chromium-rich oxide surfaces prior to decontamination
EP0406098A1 (fr) * 1989-06-27 1991-01-02 Electricite De France Procédé de dissolution d'oxyde déposé sur un substrat métallique et son application à la décontamination
FR2648946A1 (fr) * 1989-06-27 1990-12-28 Electricite De France Procede de dissolution d'oxyde depose sur un substrat metallique et son application a la decontamination
EP0727243A1 (fr) * 1995-02-20 1996-08-21 Commissariat A L'energie Atomique Mousse de décontamination à l'ozone, et procédé de décontamination utilisant cette mousse
FR2730641A1 (fr) * 1995-02-20 1996-08-23 Commissariat Energie Atomique Mousse de decontamination a l'ozone, et procede de decontamination utilisant cette mousse
US6875323B2 (en) * 1998-06-23 2005-04-05 Kabushiki Kaisha Toshiba Method of chemically decontaminating components of radioactive material handling facility and system for carrying out the same
EP1220233A2 (fr) * 2000-12-21 2002-07-03 Kabushiki Kaisha Toshiba Procédé de décontamination chimique ainsi que procédé et appareil pour le traitement de la solution de décontamination chimique
JP2002250794A (ja) * 2000-12-21 2002-09-06 Toshiba Corp 化学除染方法
EP1220233A3 (fr) * 2000-12-21 2002-09-11 Kabushiki Kaisha Toshiba Procédé de décontamination chimique ainsi que procédé et appareil pour le traitement de la solution de décontamination chimique
KR100566725B1 (ko) * 2000-12-21 2006-04-03 가부시끼가이샤 도시바 화학 오염 제거 방법
US7713402B2 (en) 2000-12-21 2010-05-11 Kabushiki Kaisha Toshiba Method for treating a chemical decontamination solution

Also Published As

Publication number Publication date
KR840007798A (ko) 1984-12-10
EP0137002A1 (fr) 1985-04-17
SE8300685L (sv) 1984-08-10
SE8300685D0 (sv) 1983-02-09
SE435329B (sv) 1984-09-17
ES529540A0 (es) 1985-08-16
ES8604701A1 (es) 1985-08-16

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