EP0475635A1 - Procédé pour enlever le cesium de solutions aqueuses ayant une haute concentration en acide nitrique - Google Patents

Procédé pour enlever le cesium de solutions aqueuses ayant une haute concentration en acide nitrique Download PDF

Info

Publication number
EP0475635A1
EP0475635A1 EP91307879A EP91307879A EP0475635A1 EP 0475635 A1 EP0475635 A1 EP 0475635A1 EP 91307879 A EP91307879 A EP 91307879A EP 91307879 A EP91307879 A EP 91307879A EP 0475635 A1 EP0475635 A1 EP 0475635A1
Authority
EP
European Patent Office
Prior art keywords
cesium
salts
aqueous solution
acid
concentration
Prior art date
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.)
Granted
Application number
EP91307879A
Other languages
German (de)
English (en)
Other versions
EP0475635B1 (fr
Inventor
Koichi C/O Government Ind. Technology Tanihara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National Institute of Advanced Industrial Science and Technology AIST
Original Assignee
Agency of Industrial Science and Technology
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
Priority claimed from JP2240420A external-priority patent/JPH0727069B2/ja
Priority claimed from JP3142272A external-priority patent/JPH0685869B2/ja
Application filed by Agency of Industrial Science and Technology filed Critical Agency of Industrial Science and Technology
Publication of EP0475635A1 publication Critical patent/EP0475635A1/fr
Application granted granted Critical
Publication of EP0475635B1 publication Critical patent/EP0475635B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • G21F9/04—Treating liquids
    • G21F9/06—Processing
    • G21F9/12—Processing by absorption; by adsorption; by ion-exchange

Definitions

  • the present invention relates to a method for removing cesium from an aqueous solution containing nitric acid in a high concentration of, for example, 1M or higher. More particularly, the invention relates to a reliable and efficient method for removing cesium from an aqueous solution containing nitric acid in a high concentration by sorption on a solid sorbent.
  • the method is of course applicable to the removal of radioactive nuclides of cesium from a high-level radioactive waste solution produced in facilities relative to atomic power plants such as a reprocessing plant for spent nuclear fuels.
  • the so-called purex process is and will be the major method for the reprocessing of spent nuclear fuels.
  • the purex process necessarily produces a large volume of high-level radioactive waste solutions which are highly acidic since they contain nitric acid in a concentration as high as 2M to 4M. Accordingly, one of the most serious issues in completing a nuclear fuel cycle is to establish a reliable and efficient method for the disposal of such high-level radioactive waste solutions while each of the heretofore proposed methods therefor is defective in one or more respects.
  • radioactive nuclides of cesium also belong to the class of the species having highest leachability.
  • great difficulties are encountered in the safety assessment of this process in relation to the safety to be secured in handling and transportation as well as in the storage of the glassy solids due to their strong radioactivity and the large quantity of heat evolved therefrom.
  • radioactive cesium is important due to a growing demand for it as a gamma-ray irradiation source in the germicidal treatment of various kinds of foods as well as the excess sludge produced in the activated sludge process for the disposal of municipal sewages.
  • inorganic ion exchangers including zeolites such as mordenite, salts of a heteropoly acid such as ammonium molybdophosphate, acidic salts of a polyvalent metal such as titanium phosphate and several insoluble ferrocyanides.
  • each of these inorganic ion exchangers heretofore proposed has its own advantages and disadvantages so that none of them is quite satisfactory as a sorbent to be used in a high-level radioactive waste solution.
  • the zeolite-based sorbents are readily dissolved in an acidic solution so that they cannot be used in a highly acidic radioactive waste solution such as those coming from the purex process.
  • heteropolyacid salts and the acidic salts of a polyvalent metal are excellent in resistance against acid, although those of the latter class are not without problems in respect of adsorptive power and selectivity of adsorption in a highly acidic medium, but their high acid resistance alone is not sufficient to ensure their practical applicability, as is discussed in IAEA-TECDOC-337, page 31 (1985), another important characteristic in the sorbent is that sorption of the species of actinide elements is as small as possible. In this regard, ammonium molybdophosphate and titanium phosphate mentioned above are poor in selectivity for the separation of cesium and the actinide elements.
  • ammonium molybdophosphate as a typical sorbent for cesium is, as though having a high sorptivity for cesium, defective from the practical standpoint of the absence of an appropriate eluent for the desoprtion of the cesium sorbed on the sorbent.
  • an insoluble ferrocyanide compound could be a sorbent for cesium with greatly increased utilizability from an aqueous solution containing nitric acid in high concentration if oxidation of the ferrocyanide by the nitric acid could be effectively prevented.
  • a highly reducing compound which might be a potential oxidation-preventing agent for ferrocyanides is readily oxidized by nitric acid, resulting in the loss of the oxidation-preventing power for ferrocyanides.
  • the present invention has an object to provide a novel method for removing cesium from an aqueous solution even when the solution contains nitric acid in a high concentration of, for example, 1M or higher, by the method of sorption on an insoluble ferrocyanide compound.
  • the present invention provides an improvement, in a method for removing cesium from an aqueous solution containing nitric acid by bringing the said aqueous solution into contact with an insoluble ferrocyanide compound as a sorbent to effect sorption of the cesium thereon, which comprises: admixing the aqueous solution with an oxidation-preventing agent selected from hydrazinium compounds, i.e.
  • amidosulphonic acid compounds including salts of an imido(bis)sulphuric acid or a nitrido(tris)sulphuric acid which can be hydrolyzed to form amidosulphonic acid in a strongly acidic medium, hydrogen peroxide, resorcine, hydroquinone, urea, thioglycolic acid and salts thereof, hydroiodic acid and salts thereof, sulfanilic acid and salts thereof, sulfanilamide, dihydroxytoluene, sulfanilhydrazine-p-sulphonic acid and salts thereof, and hydrazine compounds, e.g., methylhydrazine, phenylhydrazine, 1,1-diphenylhydrazine and tolylhydrazine, and salts thereof.
  • hydrazine compounds e.g., methylhydrazine, phenylhydrazine, 1,1-diphenylhydrazine and tolylhydra
  • the insoluble ferrocyanide compound used in the present invention includes those compounds insoluble or scarcely soluble in water obtained by the precipitation reaction of a water-soluble ferrocyanide or ferrocyanic acid with a salt or hydroxide of a polyvalent metal other than alkaline earth elements.
  • Such an insoluble ferrocyanide compound is exemplified typically by: potassium copper ferrocyanides K2Cu3[Fe(CN)6]2, K2Cu5[Fe(CN)6]2 and K2Cu11[Fe(CN)6]2, referred to as K2Cu3FC, K2Cu5FC and K2Cu11FC, respectively, hereinbelow; copper ferrocyanide Cu2Fe(CN)6, referred to as CuFC hereinbelow; potassium zinc ferrocyanide K2Zn3[Fe(CN)6]2, referred to as K2Zn3FC hereinbelow; zinc ferrocyanide Zn2Fe(CN)6, referred to as ZnFC hereinbelow; cadmium ferrocyanide Cd2Fe(CN)6, referred to as CdFC hereinbelow; nickel ferrocyanide Ni2Fe(CN)6, referred to as NiFC hereinbelow and cobalt ferrocyanide Co2Fe(CN)6, referred to as CoFC herein
  • the sorbent used in the present invention is not limited to the precipitates of these ferrocyanides per se but any solid material, such as silica gel and anion- and cation-exchange resins, supporting the ferrocyanide precipitated in its pores by in situ reaction can be used as well.
  • the improvement according to the present invention is applicable to cesium-containing aqueous solutions of which the concentration of nitric acid is 1M or higher or sufficient to cause oxidation of the ferrocyanide into ferricyanide but the invention is applicable to an aqueous solution of a lower nitric acid concentration.
  • the oxidation reaction of a ferrocyanide into ferricyanide proceeds at a substantial velocity even at room temperature when the concentration of nitric acid is 1M or higher although the exact velocity of the oxidation reaction depends on various factors such as the kind of ferrocyanide, treatment temperature and other factors.
  • the oxidation reaction of the ferrocyanide into ferricyanide can be almost completely prevented according to the present invention even when the concentration of nitric acid in the aqueous solution is 3M or higher so that the sorptive capacity of the ferrocyanide for cesium can be as large as that in the absence of nitric acid in the solution.
  • the characteristic feature of the inventive improvement consists in the admixture of a specific oxidation-preventing agent listed above to the cesium-containing aqueous solution of high nitric acid concentration.
  • a compound having a high reducing power for a ferricyanide compound into ferrocyanide is not always suitable as the oxidation-preventing agent for the ferrocyanides.
  • oxidation-preventing agents for example, urea, resorcine and amidosulphonic acid have no reducing power for ferricyanides as compared with conventional strong reducing agents such as hydroxylammonium salts, sulphites, thiosulphates and dithionites.
  • hydrazinium compounds such as hydrazine and salts thereof
  • amidosulphonic acid compounds such as amidosulphonic acid and salts thereof
  • hydrazinium compounds such as hydrazine and salts thereof
  • amidosulphonic acid compounds such as amidosulphonic acid and salts thereof
  • oxidation-preventing activity exhibiting the desired effect even when their concentration in aqueous solution is very low, in the range, for example, from 5 x 10 ⁇ 6 to 1 x 10 ⁇ 4 M in the sorption of cesium on a potassium copper ferrocyanide from an aqueous solution containing nitric acid in a concentration of 3M.
  • the effectiveness of the oxidation-preventing agents listed above depends on the kind of insoluble ferrocyanide compound used as the sorbent. This is presumably dependent on the sorptive power of the corresponding ferricyanide compound for cesium.
  • the insoluble ferrocyanide compounds in general have a higher sorptive power for cesium than the corresponding ferricyanide compounds so that the improvement of the invention can be obtained more or less in any of the insoluble ferrocyanide compounds.
  • the effectiveness of the inventive improvement is very pronounced for copper-containing ferrocyanide compounds as the sorbent as a consequence of the very low sorptive power of the corresponding copper-containing ferricyanide compounds for cesium. Therefore, recovery of cesium sorbed on copper-containing insoluble ferrocyanide can be efficiently performed by using an aqueous nitric acid solution of high concentration containing no oxidation-preventing agent as the eluent.
  • Determination of the concentration of cesium in the aqueous solution was performed for the solution with admixture of potassium chloride in a concentration of 0.1M as a sensitizer by the method of atomic absorption spectrophotometry or atomic emission spectrometry each using an air-acetylene flame.
  • insoluble ferrocyanide compounds were prepared to serve as a sorbent for cesium including: ZnFC, CdFC, two kinds of CuFC, i.e. CuFC-A and CuFC-B, NiFC and CoFC obtained as precipitates by admixture of an aqueous solution of sodium ferrocyanide with an aqueous solution of zinc nitrate, cadmium chloride, copper (II) chloride, copper (II) sulfate, nickel (II) chloride and cobalt (II) nitrate, respectively, in an amount such that the molar ratio of the transition metal element to the ferrocyanide ions was at least 2 followed by separation of the precipitates by filtration, washing with water and air-drying as the insoluble ferrocyanides of simple-salt form; and K2Zn3FC, K2Cu3FC, K2Cu5FC and K2Cu11FC obtained as precipitates by admixture of an aqueous solution of potassium ferrocyanide with an aque
  • KCoFC potassium cobalt ferrocyanide
  • MoO3FC molybdic acid ferrocyanide
  • each of the insoluble ferrocyanide compounds prepared above was taken in an exact amount of 0.01 g calculated as anhydrous compound in a stoppered Erlenmeyer flask to which 10 ml of an aqueous solution, of which the concentration of nitric acid was 3M, containing cesium chloride in a concentration of 1 x 10 ⁇ 3M and hydrazine sulphate in a concentration of 2 x 10 ⁇ 4M.
  • the flask was stoppered and shaken for 7 days in a water bath thermostatted at 25 °C. After subjecting the solution to solid-liquid separation by filtration, a portion of the filtrate was taken and analyzed for the concentration of cesium therein and the value of Kd was calculated to give the results shown in Table 1 below.
  • the experimental procedure using K2Cu3FC as the sorbent was substantially the same as in Example 1 except that the concentration of hydrazine sulphate was 5 x 10 ⁇ 6M instead of 2 x 10 ⁇ 4M and shaking of the flask was terminated after 1 hour.
  • the value of Kd was 2.0 x 104 ml/g as calculated from the residual concentration of cesium of 4.70 x 10 ⁇ 5M in the filtrate obtained by filtration.
  • the experimental procedure using K2Cu3FC as the sorbent was substantially the same as in Example 2 except for omission of the hydrazine sulphate added to the aqueous solution as the oxidation-preventing agent.
  • the value of Kd was 5.0 x 102 ml/g as calculated from the residual concentration of cesium of 6.67 x 10 ⁇ 4M in the filtrate obtained by filtration.
  • the experimental procedure was substantially the same as in Example 3 except for omission of hydrazine sulphate.
  • the value of Kd was 2.9 x 102 ml/g as calculated from the residual concentration of cesium of 7.76 x 10 ⁇ 4M in the filtrate obtained by filtration.
  • the experimental procedure was substantially the same as in Example 4 except for omission of hydrazine sulphate.
  • the value of Kd was 9.6 x 101 ml/g as calculated from the residual concentration of cesium of 9.12 x 10 ⁇ 4M in the filtrate obtained by filtration.
  • the experimental procedure using K2Cu3FC was substantially the same as in Example 2 except that the hydrazine sulphate as the oxidation-preventing agent was replaced with one of the compounds listed in Table 2 each in the concentration indicated in the same table and shaking of the flask was continued for 24 hours.
  • the values of Kd as calculated from the respective residual concentrations of cesium in the filtrates obtained by filtration are also shown in the table.
  • the experimental procedure using K2Cu3FC was substantially the same as in Example 6 except that the oxidation-preventing agent was replaced by hydroxylamine hydrochloride, sodium thiosulphate, sodium sulphite or sodium dithionite each in a concentration indicated in Table 2 or entirely omitted.
  • the values of Kd as calculated from the respective residual concentrations of cesium in the supernatant are also shown in the table.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
EP19910307879 1990-09-10 1991-08-28 Procédé pour enlever le cesium de solutions aqueuses ayant une haute concentration en acide nitrique Expired - Lifetime EP0475635B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP240420/90 1990-09-10
JP2240420A JPH0727069B2 (ja) 1990-09-10 1990-09-10 硝酸含有水溶液中のセシウムの分離方法
JP3142272A JPH0685869B2 (ja) 1991-03-29 1991-03-29 硝酸含有水溶液中のセシウムの分離方法
JP142272/91 1991-03-29

Publications (2)

Publication Number Publication Date
EP0475635A1 true EP0475635A1 (fr) 1992-03-18
EP0475635B1 EP0475635B1 (fr) 1994-12-14

Family

ID=26474332

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910307879 Expired - Lifetime EP0475635B1 (fr) 1990-09-10 1991-08-28 Procédé pour enlever le cesium de solutions aqueuses ayant une haute concentration en acide nitrique

Country Status (2)

Country Link
EP (1) EP0475635B1 (fr)
DE (1) DE69105884T2 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008002282A1 (fr) * 2006-06-29 2008-01-03 Fos International S.A. procédé de décontamination de déchets radioactifs liquides (variantes) et sorbant sélectif vis-à-vis du Cs
RU2474898C1 (ru) * 2011-06-27 2013-02-10 Федеральное государственное унитарное предприятие "Горно-химический комбинат" Способ переработки оксалатных маточных растворов и пульпообразных отходов, содержащих трансурановые элементы
RU2521606C2 (ru) * 2012-10-18 2014-07-10 Открытое акционерное общество "Чепецкий механический завод" Способ утилизации сбросных растворов в производстве тетрафторида урана
US8962907B2 (en) 2012-01-18 2015-02-24 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Method for removing radioactive cesium, hydrophilic resin composition for removing radioactive cesium, method for removing radioactive iodine and radioactive cesium, and hydrophilic resin composition for removing radioactive iodine and radioactive cesium
JP2015099139A (ja) * 2013-11-20 2015-05-28 株式会社クラレ 放射性セシウム除染方法及び放射性セシウム除染シート
US9412479B2 (en) 2013-02-19 2016-08-09 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Method and composition for removing radioactive cesium
US9536630B2 (en) 2011-12-28 2017-01-03 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Method for removing radioactive cesium, hydrophilic resin composition for removal of radioactive cesium, method for removing radioactive iodine and radioactive cesium, and hydrophilic resin composition for removal of radioactive iodine and radioactive cesium
CN110205494A (zh) * 2019-05-22 2019-09-06 浙江大学 一种吸附分离铷和铯的方法
CN112285226A (zh) * 2020-10-16 2021-01-29 中国人民解放军63653部队 废液中Pu-239、Sr-90、Cs-137快速联合分析方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102773067B (zh) * 2012-08-22 2014-09-24 中国原子能科学研究院 一种磁性铯选择性吸附剂的制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3296123A (en) * 1964-04-01 1967-01-03 William E Prout Removal of cesium from aqueous solutions by ion exchange
US3896045A (en) * 1971-08-24 1975-07-22 Belgonucleaire Sa Decontamination process for radio-active liquids
FR2346817A1 (fr) * 1976-03-31 1977-10-28 Commissariat Energie Atomique Procede de decontamination d'effluents radioactifs, notamment en antimoine et en ruthenium
FR2548042A1 (fr) * 1983-06-15 1985-01-04 Sumitomo Metal Mining Co Procede de traitement de dechets faiblement radioactifs

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3296123A (en) * 1964-04-01 1967-01-03 William E Prout Removal of cesium from aqueous solutions by ion exchange
US3896045A (en) * 1971-08-24 1975-07-22 Belgonucleaire Sa Decontamination process for radio-active liquids
FR2346817A1 (fr) * 1976-03-31 1977-10-28 Commissariat Energie Atomique Procede de decontamination d'effluents radioactifs, notamment en antimoine et en ruthenium
FR2548042A1 (fr) * 1983-06-15 1985-01-04 Sumitomo Metal Mining Co Procede de traitement de dechets faiblement radioactifs

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008002282A1 (fr) * 2006-06-29 2008-01-03 Fos International S.A. procédé de décontamination de déchets radioactifs liquides (variantes) et sorbant sélectif vis-à-vis du Cs
RU2474898C1 (ru) * 2011-06-27 2013-02-10 Федеральное государственное унитарное предприятие "Горно-химический комбинат" Способ переработки оксалатных маточных растворов и пульпообразных отходов, содержащих трансурановые элементы
US9536630B2 (en) 2011-12-28 2017-01-03 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Method for removing radioactive cesium, hydrophilic resin composition for removal of radioactive cesium, method for removing radioactive iodine and radioactive cesium, and hydrophilic resin composition for removal of radioactive iodine and radioactive cesium
US8962907B2 (en) 2012-01-18 2015-02-24 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Method for removing radioactive cesium, hydrophilic resin composition for removing radioactive cesium, method for removing radioactive iodine and radioactive cesium, and hydrophilic resin composition for removing radioactive iodine and radioactive cesium
RU2521606C2 (ru) * 2012-10-18 2014-07-10 Открытое акционерное общество "Чепецкий механический завод" Способ утилизации сбросных растворов в производстве тетрафторида урана
US9412479B2 (en) 2013-02-19 2016-08-09 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Method and composition for removing radioactive cesium
JP2015099139A (ja) * 2013-11-20 2015-05-28 株式会社クラレ 放射性セシウム除染方法及び放射性セシウム除染シート
CN110205494A (zh) * 2019-05-22 2019-09-06 浙江大学 一种吸附分离铷和铯的方法
CN112285226A (zh) * 2020-10-16 2021-01-29 中国人民解放军63653部队 废液中Pu-239、Sr-90、Cs-137快速联合分析方法

Also Published As

Publication number Publication date
DE69105884T2 (de) 1995-05-04
DE69105884D1 (de) 1995-01-26
EP0475635B1 (fr) 1994-12-14

Similar Documents

Publication Publication Date Title
US4512921A (en) Nuclear reactor cooling system decontamination reagent regeneration
Lento et al. Separation of cesium from nuclear waste solutions with hexacyanoferrate (II) s and ammonium phosphomolybdate
Del Cul et al. Technetium-99 removal from process solutions and contaminated groundwater
US6214234B1 (en) Method for the removal of cesium from radioactive waste liquids
EP0575612B1 (fr) Procede d'obtention de sorbants composites
EP0118493B1 (fr) Fixation de materiaux anioniques au moyen d'un agent de complexage
EP0475635B1 (fr) Procédé pour enlever le cesium de solutions aqueuses ayant une haute concentration en acide nitrique
Dhami et al. Biosorption of radionuclides by Rhizopus arrhizus
US4156646A (en) Removal of plutonium and americium from alkaline waste solutions
US5298166A (en) Method for aqueous radioactive waste treatment
JPH0727069B2 (ja) 硝酸含有水溶液中のセシウムの分離方法
Collins et al. Evaluation of selected ion exchangers for the removal of cesium from MVST W-25 supernate
KR100764904B1 (ko) 이온교환체를 이용한 세슘 또는 스트론튬의 방사성 핵종 제거방법
Hooper Activity removal from aqueous waste streams by seeded ultrafiltration
JPS61195400A (ja) 放射性核種を含有する廃液の処理方法
JPS62176913A (ja) ナトリウム塩含有処理液からのセシウムの分離、回収方法
US4959181A (en) Ion exchange using hydrous uranium dioxide
EP0456382B1 (fr) Méthode pour éliminer des cations radioisotopes d'un environnement aqueux en utilisant de la clinoptilolite modifiée
JPH05317697A (ja) 硝酸含有水溶液中のセシウムの分離方法
JPS62161097A (ja) 放射性核種を含有する廃液の処理法
Verguts et al. Recovery of cesium and strontium isotopes
Rimshaw Decontamination of fission product wastes with separation of kilocurie quantities of cesium, strontium, rare earths, and ruthenium
Blanco et al. Removal of Fission Products from High Level Radioactive Waste Solutions
Denton et al. Development and Testing of Two Novel and Vitrification Compatible Classes of Ion Specific Media for Application on the Hanford Waste Treatment Plant Supplemental Pretreatment and Secondary Waste Streams-11001
Burger et al. Technical requirements for the control of 129I in a nuclear fuels reprocessing plant

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19920407

17Q First examination report despatched

Effective date: 19940221

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 69105884

Country of ref document: DE

Date of ref document: 19950126

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20020823

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20020828

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20021030

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030828

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040302

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040430

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST