EP0018922B1 - Procédé de décontamination en ruthénium d'effluents radioactifs liquides et dispositif pour la mise en oeuvre de ce procédé - Google Patents

Procédé de décontamination en ruthénium d'effluents radioactifs liquides et dispositif pour la mise en oeuvre de ce procédé Download PDF

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Publication number
EP0018922B1
EP0018922B1 EP80400615A EP80400615A EP0018922B1 EP 0018922 B1 EP0018922 B1 EP 0018922B1 EP 80400615 A EP80400615 A EP 80400615A EP 80400615 A EP80400615 A EP 80400615A EP 0018922 B1 EP0018922 B1 EP 0018922B1
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EP
European Patent Office
Prior art keywords
effluent
precipitate
hydrazine
ruthenium
cupric ions
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80400615A
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German (de)
English (en)
French (fr)
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EP0018922A1 (fr
Inventor
Jean-Paul Gauchon
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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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
    • G21F9/04—Treating liquids
    • G21F9/06—Processing

Definitions

  • the present invention relates to a ruthenium decontamination process of a liquid radioactive effluent, which can be used for raw effluents or for effluents treated beforehand chemically by conventional methods.
  • radioactive effluents such as aqueous solutions originating from the treatment of irradiated nuclear fuels can be subjected to various chemical decontamination treatments in order to eliminate in particular ruthenium.
  • Most of these treatments consist in forming precipitates capable of fixing ruthenium within the effluent to be treated, for example, by adding ferrous ions and cupric ions to this effluent and then adjusting the pH of the effluent to a value of 7 to 8.5 for precipitating the corresponding copper and iron compounds, as described in FR-A-2 124 126.
  • the present invention relates to a ruthenium decontamination process of a liquid radioactive effluent which consists in forming within the effluent a precipitate capable of fixing the ruthenium.
  • the method according to the invention consists in adding to said liquid effluent a reducing agent and cupric ions to form within said effluent a precipitate on which the ruthenium is fixed, and then separating from said effluent the precipitate thus formed, and it characterized in that the reducing agent consists of hydrazine so as to form within said effluent a precipitate of cuprous oxide on which the ruthenium is fixed.
  • the pH of said liquid effluent is adjusted, beforehand, to a value greater than 7 and preferably between 7 and 10, for example by addition of sodium hydroxide.
  • the cupric ions are generated directly in said effluent by electrochemical means, by subjecting said effluent to electrolysis in a cell comprising a copper anode.
  • the process as characterized above advantageously takes advantage of the fact that by adding a reducing agent, consisting of hydrazine, for example, in the form of a salt or hydrazine hydrate, to an effluent having a pH greater than 7, the redox potential of the effluent is stabilized at appropriate values, for example of the order of -120 mV relative to a saturated calomel electrode (ECS), which then makes it possible to form in this effluent, by addition of cupric ions Cu2 + a stable precipitate of cuprous oxide on which the ruthenium is fixed, the transformation of cupric salts into cuprous oxide being obtained fairly quickly.
  • a reducing agent consisting of hydrazine, for example, in the form of a salt or hydrazine hydrate
  • the method of the invention has the advantage of not leading to an excessive volume of precipitates or of sludge and of not requiring complex operations to ensure satisfactory separation of the sludges formed during the precipitation step. .
  • the volume of sludge formed in the effluent represents only 0.2 to 0.4% of the volume of effluent.
  • the amounts of hydrazine and cupric ions added to said effluent are such that the molar ratio of hydrazine to cupric ions is between 0.5 and 1.
  • the amount of hydrazine added to said effluent is between 1 and 2.10 - 3 moles of hydrazine per liter of effluent, and the amount of cupric ions added to said effluent is between 1 and 2.10 - 3 moles of ions copper per liter of effluent.
  • the precipitates formed in said effluent electrochemically can be separated preferably by means of a hydrocyclone, the effluent then being subjected to filtration.
  • the separation and decantation of the precipitate can be favored by adding to the effluent in which the precipitate is formed an anionic polyelectrolyte to coagulate the precipitate obtained.
  • the present invention also relates to a device for implementing this method.
  • This device is characterized in that it comprises a tank provided with stirring means, means for introducing into said tank the liquid effluent to be treated and the reducing agent, means for adjusting the pH of l to the desired value.
  • effluent present in said tank means for circulating in an electrolysis cell comprising a copper anode the effluent present in said tank, means for recovering the effluent leaving said electrolysis cell, and means for separating from said effluent the precipitate of cuprous oxide formed in said effluent when it passes through said electrolysis cell.
  • said cell is provided with a polarity reverser and comprises two copper electrodes.
  • the means for separating the precipitate of cuprous oxide formed in said effluent are constituted by a hydrocyclone and by a filter.
  • the device further comprises means for recycling into said tank at least part of the separated precipitate.
  • the decontamination installation includes a tank 1 which is supplied, on the one hand, with effluent to be treated by a pipe 3 provided with a pump 5 and, on the other hand, with hydrazine hydrate by a pipe 7 provided with a pump 9.
  • the tank 1 is provided with an agitator 11 driven by a motor 12 and a pH detector 13 associated with a control member 15 which actuates a pump 17 allowing the necessary quantity to be introduced into the tank 1 by the pipe 19 of soda in order to adjust the pH of the effluent present in tank 1 to the desired value.
  • the installation also includes an electrolysis cell 23 comprising 2 copper electrodes 25 and 26 which are supplied with electric current from an alternating current generator provided with a current rectifier 27 by means of an inverter. of polarity 29, which makes it possible to connect the electrodes 25 and 26 alternately to the positive pole and to the negative pole of the electric current generator.
  • this liquid effluent is put into circulation in the electrolysis cell 23 via pipes 31 and 33 by means of a pump 35.
  • the effluent is directed into a hydrocyclone 37 which ensures the separation of the sludge formed in the effluent, this sludge being extracted by a pipe 39 and recycled into the tank 1 via the pipe 41 provided with a valve 43 or discharged through a pipe 45 provided with a valve 47 in a storage container 49.
  • valves 43 and 47 are controlled by a timer 51.
  • the separated liquid is evacuated via line 53 then filtered through a filter 55 and then extracted through line 57.
  • the agitator 11 is started to agitate the effluent present in the tank 1, and the pH of this effluent is adjusted to a value substantially equal to 9 by adding sodium hydroxide to it via line 19, this addition of sodium hydroxide being controlled by the device 1 5 which actuates the pump 17 and makes it possible to introduce the desired quantity of soda as a function of the pH detected by the pH indicator 13.
  • the effluent is then circulated in the electrolysis cell 23 by switching on the pump 35 so that the flow rate of circulation of the effluent in the cell 23 allows the desired quantity to be generated in the effluent. of copper ions.
  • the effluent in which a precipitate of cuprous oxide has formed passes into the hydrocyclone 37, which makes it possible to separate the sludge which is partially recycled in the tank 1 by switching on the timer 51 which alternately controls the opening of the valves 43 and 47.
  • the liquid is filtered on the filter 55 then evacuated through the pipe 57.
  • the direction of current flow in cell 23 is periodically reversed by alternately connecting electrodes 25 and 26 to the positive and negative poles of the electric current generator, a period d 'reverse polarity of 5 to 10 seconds to achieve the highest faradic electrodissolution yields.
  • hydrazine is used as reducing agent because experience has shown that it makes it possible to obtain, in a reproducible manner, a good stabilization of the redox potential and turns out to be of more advantageous use than other reducing agents such as, for example, hydroxylamine.
  • a raw effluent from an irradiated nuclear fuel treatment installation having the following composition is subjected to a decontamination treatment:
  • hydrazine monohydrate corresponding to 1 x 10- 3 mole 1- 1 of hydrazine and 128 mg / I of cupric ions added in the form of copper sulphate, which leads to the formation of an orange-yellow precipitate on which the ruthenium is fixed.
  • the ruthenium 106 content of the supernatant is determined and it is found that the decontamination factor in ruthenium 106 (FD), which corresponds to the ratio between the ruthenium activities of the effluent before and after the decontamination treatment, has a value of 4.6.
  • the pH of the solution is adjusted beforehand to a value of 9.3, then different quantities of hydrazine are introduced into the effluent and the effluent is then subjected to electrolysis in an electrolysis cell comprising 2 copper electrodes, at a current density of 50 milliamps per cm 2 , the amount of electricity being 4 mF per liter.
  • the precipitates formed in the liquid effluent are removed by decantation for 30 min, then the supernatant is filtered or clarified by adding aluminum hydroxide to remove the cuprous oxide remaining in colloidal form .
  • radioactive effluents which initially have pH values ranging from 2 to 11.
  • the effluent After adding 2.10- 3 mole per liter of hydrazine to these effluents, the effluent is subjected to electrolysis in a cell comprising copper electrodes at a current density of 50 milliamps per cm 2 , the amount of electricity used being 4 mF per liter.
  • the electrodissolution of approximately 2.1 0-3 mole of copper is carried out per liter of effluent.
  • the pH is adjusted to 9.5 for all the tests carried out at a pH below 9.
  • the precipitates obtained After stirring the effluent for 30 min, the precipitates obtained are decanted and the supernatant is subjected to filtration before filtration. determine its ruthenium activity.
  • a liquid effluent the initial pH of which has been adjusted to 9.3, 2.10 - 3 mole of hydrazine per liter of effluent is added to an effluent, and this effluent is subjected to electrolysis in a cell comprising electrodes copper, at different current densities, the amount of electricity used being 4 mF per liter.
  • the effluent is decanted for 30 min, and the supernatant is clarified by means of 10 mg of aluminum hydroxide per liter of effluent.
  • the radioactive liquid effluent the pH of which is adjusted to 9.5, 2.10 - 3 mole of hydrazine per liter of effluent, is added to the radioactive effluent, then the effluent is subjected to electrolysis in an electrolysis cell. comprising copper electrodes, at a current density of 50 mA / cm 2 , by varying the quantity of electricity used to generate cupric ions electrochemically in the liquid effluent.
  • the pH and the redox potential of the effluent thus treated are checked, then the ruthenium activity of the supernatant filtered on a Millipore AP 20 filter (AFNOR standard) or clarified by means of 10 mg / I is determined. aluminum hydroxide.
  • variable quantities of hydrazine hydrate and 2.10- 3 mole of cupric ions per liter of effluent are introduced into this effluent, the latter being added to the solution in the form of cupric sulfate.
  • the effluent is clarified using an anionic polyelectrolyte, then the radiochemical activity of ruthenium 106 of the supernatant is determined, after settling of the precipitate.
  • This example illustrates the results obtained during ruthenium decontamination tests on the effluent 1 above having an activity in ruthenium 106 of 3180 microcuries per m 3 , these tests being carried out on 200 l of effluent whose pH has been adjusted to 9.
  • the effluent is stirred for 30 min to ensure the transformation of all the copper into cuprous oxide, then the precipitates are decanted, optionally after flocculation by means of an anionic polyelectrolyte added at a rate of 1 mg / l, and the ruthenium decontamination factor FD is determined by measuring the 106 Ru activity of the supernatant.
  • Quantity of solid matter measured after drying at 105 ° C of the sludge obtained by decantation of one liter of effluent.
  • TMS Dry matter rate
  • the COIN cone designates a cylindrical-conical container, the cone of which, placed at the bottom of the container, has an apex angle close to 10 °.
  • cuprous oxide obtained from the copper generated by electrodissolution in the presence of hydrazine is in the form of colloidal particles of smaller dimensions than those of the cuprous oxide obtained by addition of cupric ions in the form of compounds. chemicals.
  • the process of the invention proves to be very advantageous for lowering the residual activity in ruthenium of effluents, raw or treated beforehand by a chemical process, in particular when copper is introduced electrochemically, which leads to a higher concentration factor.
  • a secondary advantage of the electrochemical route lies in the fact that the generation of hydrogen in the electrolysis cell makes it possible to slightly decrease the amount of hydrazine to be used.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
  • Removal Of Specific Substances (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Electrolytic Production Of Metals (AREA)
EP80400615A 1979-05-07 1980-05-06 Procédé de décontamination en ruthénium d'effluents radioactifs liquides et dispositif pour la mise en oeuvre de ce procédé Expired EP0018922B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7911468A FR2456371A1 (fr) 1979-05-07 1979-05-07 Procede de decontamination en ruthenium d'effluents radio-actifs liquides et dispositif pour la mise en oeuvre de ce procede
FR7911468 1979-05-07

Publications (2)

Publication Number Publication Date
EP0018922A1 EP0018922A1 (fr) 1980-11-12
EP0018922B1 true EP0018922B1 (fr) 1983-04-06

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EP80400615A Expired EP0018922B1 (fr) 1979-05-07 1980-05-06 Procédé de décontamination en ruthénium d'effluents radioactifs liquides et dispositif pour la mise en oeuvre de ce procédé

Country Status (5)

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US (1) US4379082A (enExample)
EP (1) EP0018922B1 (enExample)
JP (1) JPS5619500A (enExample)
DE (1) DE3062591D1 (enExample)
FR (1) FR2456371A1 (enExample)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58169215U (ja) * 1982-05-07 1983-11-11 日本精工株式会社 動圧流体軸受
JPS5988692A (ja) * 1982-11-15 1984-05-22 動力炉・核燃料開発事業団 硝酸蒸発処理におけるルテニウムの除染効率改良法
FR2538603B1 (fr) * 1982-12-23 1988-07-01 Commissariat Energie Atomique Procede de conditionnement de dechets constitues par des particules metalliques radioactives telles que les fines de dissolution des elements combustibles irradies
GB2146486B (en) * 1983-09-08 1987-10-21 British Nuclear Fuels Ltd Treatment of effluents
US4615776A (en) * 1983-10-21 1986-10-07 Shinko-Pfaudler Company Electrolytic decontamination process and process for reproducing decontaminating electrolyte by electrodeposition and apparatuses therefore
US4790882A (en) * 1985-03-14 1988-12-13 Autospa Corporation Flushing and recharging method for the cooling system of an automotive engine
GB8719045D0 (en) * 1987-08-12 1987-10-07 Atomic Energy Authority Uk Liquid treatment process
DE68908564T2 (de) * 1989-11-20 1994-03-31 Agfa Gevaert Nv Vorrichtung für elektrolytische Silberrückgewinnung.
US5431825A (en) * 1992-10-29 1995-07-11 Chemical Waste Management, Inc. Method for the reduction and stabilization of metals
US6916427B2 (en) * 2002-05-03 2005-07-12 Ira E Whitlock Electrochemical method for treating wastewater
EP2076714B1 (en) * 2006-10-18 2016-08-31 Lean Flame, INC. Energy release/conversion device
UA102633C2 (ru) 2009-09-13 2013-07-25 Лин Флейм, Инк. Вихревое устройство для предварительного смешивания, предназначенное для устройств (варианты) с камерой сгорания

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3330771A (en) * 1961-11-30 1967-07-11 Nippon Soda Co Process for the removal of watersoluble ionic radioactive waste from water
BE758100A (fr) 1969-10-28 1971-04-01 Diffusion De Procedes Et Breve Procede et dispositif pour le traitement a partir d'ions metalliques deliquides divers, notamment de l'eau (
FR2124126B1 (enExample) * 1971-02-08 1974-03-01 Commissariat Energie Atomique
US4116863A (en) * 1976-03-31 1978-09-26 Commissariat A L'energie Atomique Method of decontamination of radioactive effluents

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Publication number Publication date
EP0018922A1 (fr) 1980-11-12
FR2456371B1 (enExample) 1981-08-14
JPS5619500A (en) 1981-02-24
US4379082A (en) 1983-04-05
DE3062591D1 (en) 1983-05-11
FR2456371A1 (fr) 1980-12-05

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