German ist2008 ecology of technetium IPCE RAS

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Recent advances in technetium in the environmental and radioactive wastes. 2008 - plenary lecture.

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German ist2008 ecology of technetium IPCE RAS

  1. 1. RECENT ADVANCES IN TECHNETIUMRECENT ADVANCES IN TECHNETIUM ENVIRONMENTALLY FOCUSEDENVIRONMENTALLY FOCUSED STUDIESSTUDIES RUSSIAN ACADEMY OF SCIENCES A.N. FRUMKIN INSTITUTE OF PHYSICAL CHEMISTRY AND ELECTROCHEMISTRY 31/4 Leninsky prospect, Moscow , 119991, RUSSIA, Fax: 7-495- 335-17-78 IST-2008 , Port-Elizabeth 7-10 Oct. 2008, South Africa KONSTANTIN E. GERMAN
  2. 2. 2008 – The Year of Tc2008 – The Year of Tc  Plan of presentationPlan of presentation  Tc in the environments – sources,Tc in the environments – sources, history and modern trends.history and modern trends.  Tc in acidic and basic HLW.Tc in acidic and basic HLW.  Different methods of Tc HLWDifferent methods of Tc HLW treatment (insoluble residues, liquidtreatment (insoluble residues, liquid wastes discharges, in-tank storage,wastes discharges, in-tank storage, vitrification, plantsvitrification, plants decommissioning, transmutationdecommissioning, transmutation projects )projects )  Chemical species of Tc in wasteChemical species of Tc in waste and environmentand environment  Physico-chemical aspects of TcPhysico-chemical aspects of Tc (colloids and nanoparticles)(colloids and nanoparticles)
  3. 3. Saying “Tc” here we mean Tc-Saying “Tc” here we mean Tc- 99g99g  ββ-emitter-emitter (T(T½½ == 2*102*1055 yy)) accumulating with ~6% yield byaccumulating with ~6% yield by U, Np or Pu fission =U, Np or Pu fission = 00.8 – 1 kg.8 – 1 kg//tt--UU  Tc concentration in reprocessing solutionsTc concentration in reprocessing solutions ~~ 5-805-80 mg/Lmg/L  Oxidation statesOxidation states:: 00, +1, + 2, +2.5,, +1, + 2, +2.5, +3+3,, +4+4 ,, +5+5,, +6,+6, +7+7  InsolubleInsoluble εε-phases = Tc metal alloys with Mo, Ru, Pd-phases = Tc metal alloys with Mo, Ru, Pd  VolatileVolatile as:as:  TcTc22OO77, HTcO, HTcO44 at T>100at T>100oo CC  TcO2 and Tc-metalTcO2 and Tc-metal (T>350(T>350oo C+OC+O22););  MTcOMTcO44 for M = Na, K, Cs atT>600for M = Na, K, Cs atT>600oo C =C = vitrificationvitrification??  InIn WATERWATER : Extremely high migration rate :: Extremely high migration rate : TcOTcO44 --
  4. 4. Technetium in the environmentTechnetium in the environment in 1986, NEA_TDB –RARD in 1999in 1986, NEA_TDB –RARD in 1999  An exceptional issue of “Technetium in the environment” in 1986 although made ofAn exceptional issue of “Technetium in the environment” in 1986 although made of independent parts was a complete presentation of all the pre-Chernobyl ideas andindependent parts was a complete presentation of all the pre-Chernobyl ideas and results :results : “Technetium in the Environment” (Proc. CEC-RPP – SERE CEA Seminar -“Technetium in the Environment” (Proc. CEC-RPP – SERE CEA Seminar - Cadarache, 1984), Eds.: G. Desmet and C. Myttenaere, Elsevier Publishers, L&N-Y. (1986).Cadarache, 1984), Eds.: G. Desmet and C. Myttenaere, Elsevier Publishers, L&N-Y. (1986).  13 years later an excellent review of NEA-TDB summed up the chemical13 years later an excellent review of NEA-TDB summed up the chemical thermodynamics of Tc :thermodynamics of Tc : Rard J.A., Rand M.H., Anderegg G., Wanner H., ChemicalRard J.A., Rand M.H., Anderegg G., Wanner H., Chemical thermodynamic of technetium. Eds. Sandino Amalia M., Osthols E. NEA (1999) Elsieverthermodynamic of technetium. Eds. Sandino Amalia M., Osthols E. NEA (1999) Elsiever Publ. Amsterdam.Publ. Amsterdam.  Time passed being characterized with the controversy of nuclear industry present andTime passed being characterized with the controversy of nuclear industry present and future status, drastic for Tc-99 originating mostly as the uranium fission product.future status, drastic for Tc-99 originating mostly as the uranium fission product.  The definite stop in nuclear development would fix Tc further accumulation but now isThe definite stop in nuclear development would fix Tc further accumulation but now is clearly not the case and we appreciate the authors were continuing efforts in Tcclearly not the case and we appreciate the authors were continuing efforts in Tc environmentally focused sciences.environmentally focused sciences.  This report is devoted to some principal results of my laboratory with someThis report is devoted to some principal results of my laboratory with some others mentioned when necessaryothers mentioned when necessary..
  5. 5. Technogenic sources of Tc to theTechnogenic sources of Tc to the environmentsenvironments  Tc present on EarthTc present on Earth  From U and Th spontaneous fission = 50 kgFrom U and Th spontaneous fission = 50 kg  From Mo(n,g)Mo99(b)Tc99 reaction s = 50 kgFrom Mo(n,g)Mo99(b)Tc99 reaction s = 50 kg  Accumulation ofAccumulation of 9999 ТсТс in nuclear industryin nuclear industry ≈≈ 2.5 g/d / 100 MW2.5 g/d / 100 MW    in NPP reactorsin NPP reactors == 8.58.5 tonton//yearyear Discharge sources of TcDischarge sources of Tc ::  Explosions in atmosphereExplosions in atmosphere 1140 TBq (Tera=1040 TBq (Tera=101212 )) == 220220 kgkg Chernobyl accidentChernobyl accident = 82= 82 kgkg  NPPNPP 1М1МBqBq //yearyear 1000 М1000 МWtWt ((electrelectr.),.), ii.е. :.е. :  InIn 20020077 release from NPP wasrelease from NPP was ≈≈ 40400 М0 МBqBq ТсТс == 200200 gg  Reprocessing plantsReprocessing plants ≈≈ 10%10% of NuFuCyof NuFuCy  1952-1986 :1952-1986 : == 20002000 kgkg ТсТс  Enrichment UEnrichment U (oper. with recycl. U):(oper. with recycl. U): 90%90% ≈≈ 4.104.101010 BkBk Тс/Тс/yy = 4,5= 4,5 kg-Tckg-Tc//yy  3-5 time rise in Tc discharges on decommissioning3-5 time rise in Tc discharges on decommissioning
  6. 6. Different approaches to handlingDifferent approaches to handling the Tc-radwastesthe Tc-radwastes  Dilution in natural watersDilution in natural waters ((only two isotopesonly two isotopes β−β− 33 H andH and 9999 TcTc)) (UK(UK,, Russia -historicRussia -historic))  Underground injection HLW, MLWUnderground injection HLW, MLW ((Tomsk, KrasnoyarskTomsk, Krasnoyarsk,, DimitrovgradDimitrovgrad))  Tank farms storageTank farms storage ((military wastes, historic wastesmilitary wastes, historic wastes))  Vitrification of historic wastes, vitrification of raffinatesVitrification of historic wastes, vitrification of raffinates  Metal formsMetal forms  New venture formsNew venture forms  Separation and storageSeparation and storage  Separation ant transmutationSeparation ant transmutation
  7. 7. The 1995-2005 years wereThe 1995-2005 years were ТсТс marked by severemarked by severe confrontation of Norwegian “greens” with Sellafieldconfrontation of Norwegian “greens” with Sellafield authorities for B205-MAGNOXauthorities for B205-MAGNOX discharges into the Irish sea -discharges into the Irish sea - 180180 kgkg-Тс/-Тс/yearyear Тс-Тс-to-sea standard for Sellafieldto-sea standard for Sellafield ( B205 + EARP-B211 + THORP )( B205 + EARP-B211 + THORP ) – 19919955-200-20000 - 200 Т- 200 ТBqBq-Тс-Тс – 2002000-2000-2003 - 90 Т3 - 90 ТBkBk-Тс-Тс – TPPBrTPPBr - April- April 23-2423-24 -- 20032003 B211 = 10 HLW tanksB211 = 10 HLW tanks 10501050 cub. m eachcub. m each :: 5 tanks for5 tanks for “MAC”“MAC” 2 tanks– sludge2 tanks– sludge 2 tanks - THORP2 tanks - THORP 1 – empty in 20031 – empty in 2003 EARPEARP
  8. 8. Pollution of the North seaPollution of the North sea,, caused bycaused by Sellafield, UKSellafield, UK)) Тс contentТс content In the samples collected in 1999 - 2001In the samples collected in 1999 - 2001  water = 0.01- 0.07 Bq/Lwater = 0.01- 0.07 Bq/L  algae = 510 Bq/kgalgae = 510 Bq/kg ( ! )( ! )  lobsters = 33 - 42 Bq/kglobsters = 33 - 42 Bq/kg ( ! )( ! ) (acc. to(acc. to Bellona,Bellona, Norvege)Norvege) Risks of refused distribution of Norvege sea-foodsRisks of refused distribution of Norvege sea-foods
  9. 9. Tc discharges in 2002-2005 The sum of total-beta activity (excluding tritium) from all nuclear installations has fallen significantly over the past 15 years. Total emissions are dominated by discharges from the nuclear fuel plant at Springfields and to a lesser extent the reprocessing plant at Sellafield. The two installations together contribute approximately 98 % of the overall discharges. The high, but decreasing total-beta discharges from Sellafield are mainly attributable to the radionuclide Technetium-99. The reduction of Sellafield’s total-beta discharges from 2002 to 2005 is a result of the significant reduction in Technetium-99 discharges, due to the vitrification process, since 1994 for oxide fuels and 2003, for magnox fuels. Discharge of Tc-99 to sea (primarily from treatment of stored Magnox wastes) has been reduced between 1994 and 2005. The total beta discharges from Sellafield (2002: 112 TBq, 2003: 83 TBq, 2004: 73 TBq, 2005: 43 TBq) were previously mainly attributable to the radionuclide Technetium-99 (2002: 85 TBq, 2003: 37 TBq, 2004 14 TBq, 2005: 6,7 TBq ), for which abatement technology was installed in 2004. The reduction of Sellafield’s total beta discharges in 2005 is due to the reduction of Technetium-99 (2004 14 TBq, 2005: 6,7 TBq),
  10. 10. Tc releases in Europe  For other European facilities the annual Tc release is negligible, no Tc was detected in Baltic sea due to Chernobyl accident (Holm, Aarkrog, 1990-91) Mayak Karachay lake VVER 3*10-2
  11. 11. Tc behavior during theTc behavior during the underground HLW storageunderground HLW storage  Pretreatment : рН +Pretreatment : рН + complexones + . . .complexones + . . . (contradictory demands :(contradictory demands : criticity risks - migration )criticity risks - migration )  Injection into the sandy levelsInjection into the sandy levels – collectors– collectors  Migration controlMigration control  Tc sorption at the minerals andTc sorption at the minerals and rocks was studied beforerocks was studied before  Main conclusionsMain conclusions  Тс(Тс(VII) has high migrationVII) has high migration mobilitymobility  Тс(Тс(IV) may form both immobileIV) may form both immobile TcOTcO22 and mobile complexesand mobile complexes Guerman K.E., Kosareva I.M., Peretroukhin V.F.,Guerman K.E., Kosareva I.M., Peretroukhin V.F., Savushkina M.K., Egorov N.N., Kudryavtsev E.,Savushkina M.K., Egorov N.N., Kudryavtsev E., Revenko Yu.A. ICEM'95. V.1. Cross-cutting IssuesRevenko Yu.A. ICEM'95. V.1. Cross-cutting Issues and management of high-level waste and spent fuel.and management of high-level waste and spent fuel. (Eds.: S.Slate, Feizollahi, C.Creer), NY, 1995, p. 713 – 722 .(Eds.: S.Slate, Feizollahi, C.Creer), NY, 1995, p. 713 – 722 . clay
  12. 12. Tc speciation in simulated radioactive wastes conditionnedTc speciation in simulated radioactive wastes conditionned for the underground injections (1980-88, 1994, 2000)for the underground injections (1980-88, 1994, 2000)  TcOTcO44 -- - is highly migrative- is highly migrative  Radiolyses in presence ofRadiolyses in presence of organic components lead toorganic components lead to the reduction of Тс(VII) tothe reduction of Тс(VII) to TcTc((V, IV, III)V, IV, III)  Acetate complexesAcetate complexes Тс(Тс(V, IV,V, IV, III) exist but the data areIII) exist but the data are scattered and the structurescattered and the structure not systematically studiednot systematically studied  Acetate complexes ofAcetate complexes of Тс(Тс(III)III) could co-exist withTc(VII) .could co-exist withTc(VII) . EXAFS ROBL_ESRFEXAFS ROBL_ESRF 4 3 2 1 0 FourierTransformMagnitude 543210 R + ∆ (Å) experiment fit -10 -5 0 5 10 k3 χ(k) 141210864 k(Å -1 )
  13. 13. Russians experience of Tc separation andRussians experience of Tc separation and conversion (decl. avail. for CEA France 1994-1997)conversion (decl. avail. for CEA France 1994-1997) Spitsyn V.I., Kuzina A.F., Prokopchuk Yu. Z., Chepurkov G.Ya. , German K.E.,Spitsyn V.I., Kuzina A.F., Prokopchuk Yu. Z., Chepurkov G.Ya. , German K.E., Oblova A.A.,Oblova A.A.,Kryuchcov S.V.Kryuchcov S.V. Preparation of technetium metal by thermalPreparation of technetium metal by thermal decomposition ofdecomposition of tetrabutylammonium pertechnetate in inert gas atmospheretetrabutylammonium pertechnetate in inert gas atmosphere.. Report IReport IPCASPCAS, N-P-2907, 1983., N-P-2907, 1983. Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., German K.E., OblovaSpitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., German K.E., Oblova A.A.,A.A., Kryuchcov S.V., Dzekun E.G., Sokhina L.P.Kryuchcov S.V., Dzekun E.G., Sokhina L.P. Precipitation technology forPrecipitation technology for technetium separationtechnetium separation from radioactive wastesfrom radioactive wastes. Report Mayak/IPCAS- 1984.. Report Mayak/IPCAS- 1984. Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., German K.E., OblovaSpitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., German K.E., Oblova A.A.,A.A., Kryuchcov S.V., Tzarenko A.F., Akopov G.A., Krinitsyn A., Kapitonov V.I.,Kryuchcov S.V., Tzarenko A.F., Akopov G.A., Krinitsyn A., Kapitonov V.I., Galkin A.,Maksimenko A., Berezuk N., Mezentsev V.I.Galkin A.,Maksimenko A., Berezuk N., Mezentsev V.I. Technology of technetiumTechnology of technetium recovery from radwastesrecovery from radwastes.Report Mayak /IPCAS/ Khlopin Radievy.Inst.,1985, N P-.Report Mayak /IPCAS/ Khlopin Radievy.Inst.,1985, N P- 3171. 32 p.3171. 32 p. Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., Guerman K.E.,Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., Guerman K.E., Oblova A.A.,Kryuchcov S.V., Kapitonov V.I., Mezentsev V.I.Oblova A.A.,Kryuchcov S.V., Kapitonov V.I., Mezentsev V.I. Improuvment ofImprouvment of anion exchange technetiumanion exchange technetium recovery from radwastes using TBP as eluentrecovery from radwastes using TBP as eluent.. Report Mayak -IPC AS. 1985, N P-3066 , 82 P.Report Mayak -IPC AS. 1985, N P-3066 , 82 P. German K.E., Kuzina A.F., Spitsyn V.I. Patent:German K.E., Kuzina A.F., Spitsyn V.I. Patent: Method of technetium carbideMethod of technetium carbide preparationpreparation. USSR. Patent No 1258016, 1986.2. USSR. Patent No 1258016, 1986.2
  14. 14. Russian approach to Tc separation in PUREX included (1980-1986):Russian approach to Tc separation in PUREX included (1980-1986): extraction at the first extraction stage, back extraction at the U-Puextraction at the first extraction stage, back extraction at the U-Pu separation stage, anion-exchange separation at QuatPhosBase AER,separation stage, anion-exchange separation at QuatPhosBase AER, purification at VP-1AP-AER, denitrification with formic acid or Hpurification at VP-1AP-AER, denitrification with formic acid or H22O-SH,O-SH, precipitation of KTcOprecipitation of KTcO44 or Ror R44NTcONTcO44 and its conversion to metal Tcand its conversion to metal Tc  Conversion to metal:Conversion to metal:  Search for theSearch for the conditions ( Ar-6%H2,conditions ( Ar-6%H2, gaz product evaquation,gaz product evaquation,  Products - volatile andProducts - volatile and solid,solid,  Russ. Inorg. Chem-2002Russ. Inorg. Chem-2002 -47-No5-47-No5 MTcO4 M = Solubility in water at 25°C Density g/ml Association constant in water, L/M Me4N+ 0.135 ± 0.005 0.096 [8] 1,67 - Et4N+ (2.5 ± 0.7) x 10-2 1.24 x 10-2 at 20°C 1,34 - Pr4N+ (8.7 ±0.2) x 10-3 7.8 x 10-3 [8] 1,26 2,6 ± 0,4 Bu4N+ (4.3 ± 0.20) x 10-3 4.2 x 10-3 at 20°C 1,17 15 ± 3 Pent4N+ (7.9 ± 0.2) x 10-4 1,12 27 ± 5 Hex4N+ (7.1 ± 0.5) x 10-5 1,07 40 ± 5 Hept4N+ (8.8 ± 0.8) x 10-6 1,03 52 ± 5 p[(C4 H9 )4 N]OH (aqueouse) ↔ [(C4 H9 )4 NOH]p (aqueouse) (8) [(C4 H9 )4 N]+ (aqueouse) + TcO4 - (aqueouse) ↔ [(C4 H9 )4 N]TcO4 (solide) (9) [(C4 H9 )4 NOH]p (aqueouse) + TcO4 - (aqueouse) ↔ [(C4 H9 )4 NOH]p-1 TcO4 (aqueouse) + OH- (10) HTcO4 ↔ H+ +TcO4 - (Tc Ka ) Tc Ka /( Tc Ka + [H+ ]) = [TcO4 - ] /([TcO4 - ]+ [HTcO4 ]) = [TcO4 - ] /[Tc]tot The Tc Ka was found equl to 4.02 M which is in very good agreement with [1] ] [i] 1 - Ashley K.R., Ball J. R. Solv. Extr. Ion Exchange, 1994, 12(2), p.239-259.
  15. 15. Co-precipitation of Tc(VII) with BuCo-precipitation of Tc(VII) with Bu44NReONReO44 from 100 ml 1.0 M NaOH, [ TcOfrom 100 ml 1.0 M NaOH, [ TcO44 -- ] = 5*10] = 5*10-4-4 M, [ BuM, [ Bu44NN++ ]] = 0.005 - 0.02 M, reagent = 0.1M NH= 0.005 - 0.02 M, reagent = 0.1M NH44ReOReO44 0 0.2 0.4 0.6 0.8 1 100 102 104 106 108 110 Total volume, % Tc fraction remained in the solution 0,02M Bu4N 0,01M Bu4N 0.005M Bu4N ∆∆V= +3%V= +3%
  16. 16. Eh-pHEh-pH PourbaixPourbaix diagram for Tcdiagram for Tc  The solubility of Tc(IV) remains independentThe solubility of Tc(IV) remains independent of pH until around 13.5, when a smallof pH until around 13.5, when a small increase can be seen which continues toincrease can be seen which continues to increase linearly with pH.increase linearly with pH.  Modelling suggests that this increase occursModelling suggests that this increase occurs as the species TcO(OH)as the species TcO(OH)33 −− is formed. Theis formed. The formation constant was estimated with dataformation constant was estimated with data from this study and was found to befrom this study and was found to be loglogKK22=−21.6±0.3.=−21.6±0.3.  Authors:Authors: Peter Warwick | S. Aldridge | NickPeter Warwick | S. Aldridge | Nick Evans | Sarah Vines - Rad. Acta 2007Evans | Sarah Vines - Rad. Acta 2007 TcO(OH)3 − Tc-O Tc-Tc C.N. R σ2 C.N. R σ2 6 2.03 0.006 1.5 2.56 0.005 Tc(OH)4(H2O)2 and E. Breynaert, D. Dom, J. Vancluysen,A. Maes 2007-8
  17. 17. Tc oxides & hydroxidesTc oxides & hydroxides TcTc22OO55- decomposition of- decomposition of TcTc22OO55*nH*nH22O at 100O at 100oo CC TcTc22OO55*nH*nH22O – gamma inO – gamma in NaOH + i-BuOHNaOH + i-BuOH TcTc44OO55*14H*14H22O hydrolisisO hydrolisis of Kof K33TcTc22ClCl88 TcTc44OO5 -5 - thermolisis ofthermolisis of TcTc44OO55*14H*14H22OO Mazzi,1974 - TcMazzi,1974 - Tc22OO33 Inorganica Chimica Acta, Volume 9,Inorganica Chimica Acta, Volume 9, 1974, Pages 263-268 G. A. Mazzocchin, F.1974, Pages 263-268 G. A. Mazzocchin, F. Magno, U. Mazzi, R. PortanovaMagno, U. Mazzi, R. Portanova Tc Oxide Parameters for inner electrons (Tc3d3/2,5/2) E(Tc) Half-width 1 Tc2O5 256,6 1,8 2 Tc2O5*nH2O 256,0 1,7 3 TcO2 255,2 1,8 4 TcO2*1.6H2O 255,4 2 5 Tc4O5*14H2O 255,9 1,8 6 Tc4O5 255,0 (0,4) 253,6 (0,4) (I1:I2=1:1.3) 3.5 7 Tc2O7 - volatile Possible fractional reduction of polymers Haefner - Sattelberger [Mo3O4(DMF)9]4+ Preparation and Characterization of Phosphine Complexes of Technetium Possessing a Metal-Metal Bond Order of 3.5. F. A. Cotton, S.C. Haefner and A. P. Sattelberger Inorg. Chem. 1996, 35, 1831.
  18. 18. Tc under HAW vitrification conditionsTc under HAW vitrification conditions  No stable Tc silicates were found before – but now weNo stable Tc silicates were found before – but now we know about Tc sodalite although losing in structureknow about Tc sodalite although losing in structure stability to cancrinite in presence of common nitratestability to cancrinite in presence of common nitrate  Pertechnetates are volatile at temp.Pertechnetates are volatile at temp. > 600> 600oo CC Reduced Tc valence formsReduced Tc valence forms ––  Tc(IV) no interaction with silicatesTc(IV) no interaction with silicates  Tc(0) no interaction with silicatesTc(0) no interaction with silicates  both volatilize in air at 350both volatilize in air at 350 oo CC Tc separation before HAW vitrification is preferableTc separation before HAW vitrification is preferable
  19. 19. Methods for Tc separation from alkaline andMethods for Tc separation from alkaline and neutral solutionsneutral solutions - Not easy when Tc species is different from Tc(VII)- Not easy when Tc species is different from Tc(VII) (Schroeder(Schroeder, 1996 -, 1996 - HanfordHanford:: treatment with Streatment with S22OO88 etc.etc. EXTRACTION Ketones : Aceton, Methyl-ethyl-ketone,) ТPPBr/ТPAsBr/CCl4 Polyglicoles Chromatography QuatPhosBase(KHL-Rad- Inst) +VP-1АP(IPCERAS) (= RAILEX) for technology HPLC - DIONEX-AS11 (for anallyt separation from MoO4/I/Br/ClO4/TcO4) Not a problem compared to acidic, quite efficient are several methods used in Russia in 1980-85 solidexsolidex TPPBrTPPBr ((developed for HLWdeveloped for HLW B205-MAGNOX)B205-MAGNOX)
  20. 20. The SRS waste volumes (Table 2.4 of "Integrated Database Report - 1993: S.Spent Fuel and Radioactive Waste Inventories, Projections, and Characteristics,”] Tc-99 quantities (Table 2.11), and Tc-99 concentrations calculated from these data Volume, Tc-99, Ci [Tc-99], [Tc], 10Volume, Tc-99, Ci [Tc-99], [Tc], 1066 KdKd liters Ci/liter g/literliters Ci/liter g/liter totaltotal Liquid 61.4 1.68E+04 2.74E-03 0.162 -Liquid 61.4 1.68E+04 2.74E-03 0.162 - Sludge 13.9 1.14E+04 8.20E-03 0.483 3Sludge 13.9 1.14E+04 8.20E-03 0.483 3 Salt Cake 53.8 2.78E+03 5.17E-04 0.0305 0.2Salt Cake 53.8 2.78E+03 5.17E-04 0.0305 0.2 Overall waste 129.1 3.098E+04 2.40E-03 0.141 -Overall waste 129.1 3.098E+04 2.40E-03 0.141 - Question to be answered : Which components absorb Tc with KdQuestion to be answered : Which components absorb Tc with Kd higher than 3 and are resistant to leaching?higher than 3 and are resistant to leaching? Reducing Grout Tank Equipment (e.g. slurry pump) CLSM 2000# grout Isolation Valve Capped Grout fill Underground line (valve closed) Underground line (line capped) Service Line (e.g. steam, air) Formwork (typ) Diversion Box Risers (typ) SRS TYPE IV HIGH LEVEL WASTE TANK
  21. 21. 9999 Tc concentrations found inTc concentrations found in various tank sludgesvarious tank sludges atat SRSSRS TankTank NumberNumber [Tc-99],[Tc-99], mCi/g driedmCi/g dried solidssolids ReferenceReference 1717 0.4620.462 d'Entremont etd'Entremont et al. 1997al. 1997 20, white20, white solidssolids 0.340.34 d'Entremont andd'Entremont and Hester 1996Hester 1996 20, brown20, brown solidssolids 0.940.94 d'Entremont andd'Entremont and Hester 1996Hester 1996 4242 0.220.22 Hay 1999Hay 1999 5151 0.210.21 Hay 1999Hay 1999 88 0.220.22 Hay 1999Hay 1999 1111 0.340.34 Hay 1999Hay 1999 The discovery of relativelyThe discovery of relatively highhigh 9999 Tc concentrationsTc concentrations in inorganic mineralin inorganic mineral sludge heels taken fromsludge heels taken from some tanks at the US-some tanks at the US- DOE Savannah River SiteDOE Savannah River Site (SRS) has prompted(SRS) has prompted investigations of Tcinvestigations of Tc uptake from alkalineuptake from alkaline highly active waste (HAW)highly active waste (HAW) by solid adsorbentsby solid adsorbents
  22. 22. Sludge components as carriersSludge components as carriers for Tc(VII) and Tc(IV)for Tc(VII) and Tc(IV) . S O D I U M O X A L A T E . N a 2 C 2 O 4 . C R Y O L I T E . N a 3 A l F 6 A L U M I N O S I L I C A T E S C A N C R I N I T E S O D A L I T E W H I T E S O L I D S . P L A T I N U M G R O U P . M E T A L S R h , R u , P d M E T A L H Y D R O X I D E S ( F e , C r , M n ) ( O ) ( O H ) B R O W N S O L I D S S O L I D S L U D G E C O M P O N E N T S TiO2 was also tested
  23. 23. Study of Tc uptake withStudy of Tc uptake with AluminosilicatesAluminosilicates under oxidizing conditions at 70-130under oxidizing conditions at 70-130oo CC  TcOTcO44 -- is too largeis too large and therefore it isand therefore it is excludedexcluded from thefrom the aluminosilicatealuminosilicate structure in bothstructure in both cancrinite andcancrinite and sodalitesodalite Solution Formed solid Kd 10-3 -10-5 M Tc 0.2-5M NaOH 0.5-5 M NaNO3 Cancrinite less 1 10-3 -10-5 M Tc 0.2-5M NaOH NaNO3 free Sodalite less 1  Literature data have demonstrated the possibility ofLiterature data have demonstrated the possibility of ClOClO44 -- and MnOand MnO44 -- co-crystallisaton with aluminosilicates :co-crystallisaton with aluminosilicates : purple Na8[AlSiO4]6(MnO4)2 (Weller,1999 etc.) OUR EXPERIMENTS on TcOOUR EXPERIMENTS on TcO44 -- (reaction: NaAlO2+Na2SiO3+NaOH)
  24. 24. Case of Aluminosilicates formedCase of Aluminosilicates formed in concentrated Tc(VII) solutionin concentrated Tc(VII) solution  [Tc] = 0.2 M[Tc] = 0.2 M  in NaNO3 solutions - cancrinitein NaNO3 solutions - cancrinite  in NaNO3-free solutions - sodalitein NaNO3-free solutions - sodalite  Although NMR spectrum presentedAlthough NMR spectrum presented shift typical for coordinated Tc(VII)shift typical for coordinated Tc(VII) its concentration is very lowits concentration is very low  Dissolution in NaHFDissolution in NaHF22 and LSC hasand LSC has shown : [Tc] in solid cancrinite wasshown : [Tc] in solid cancrinite was 57 mg/kg ~ 100 times less than in57 mg/kg ~ 100 times less than in initial solutioninitial solution  Tc is excluded from theTc is excluded from the aluminosilicate structure ofaluminosilicate structure of Fig. 1. NMR-99 Tc spectrum of the aluminosilicate containing 57 mg-Tc/kg. Tc spectrum presents evidence for -30 ppm shift characteristic of coordinated pertechnetate
  25. 25. Study of Tc uptake withStudy of Tc uptake with AluminosilicatesAluminosilicates (AS)(AS) underunder reducingreducing conditionsconditions ((0.2M N0.2M N22HH55Cl, 1M NaNOCl, 1M NaNO33,, TT = 80= 8000 С, t = 3 d)С, t = 3 d) Precipitation of cancrinite↓ Leaching conditions: NaOH M Tc yield, % Leaching agent: T, o C Leaching yield , Tc, % 3 hour 1 day 10 days 2.0 18.9 1M NaOH 20 0.8 1 3.7 4.0 32 2M NaOH 20 0.8 1.2 2.0 2.0 25.2 0.1M NaOH + 0.25 M H2 O2 60 25 26.9 27 2.0 18.9 0.1M NaOH + 0.5 H2 O2 18 4 6.9 7 4.0 32 0.1M NaOH + 0.5 H2 O2 18 6.5 6.9 11 Under reducing conditions Tc uptake by AS is importantUnder reducing conditions Tc uptake by AS is important Tc(IV) in AS is resistant to leaching due to occlusionTc(IV) in AS is resistant to leaching due to occlusion
  26. 26. Study of Tc(VII) sorptionStudy of Tc(VII) sorption by crystalline TiOby crystalline TiO22 under oxidizing conditionsunder oxidizing conditions  Tc(VII) was sorbed byTc(VII) was sorbed by TiOTiO22 from neutral solutionfrom neutral solution with Kwith Kdd = 30 ml/g.= 30 ml/g.  However, the KHowever, the Kdd at pH=10at pH=10 was only 3.3 ml/gwas only 3.3 ml/g  No affinity to Tc(VII) wasNo affinity to Tc(VII) was noted fornoted for TiOTiO22 at pH=12at pH=12 and higherand higher..  Among the minerals tested for Tc(VII) uptake, high-density TiO2 was the most efficient MST and Silicotitanates not tested yet..?
  27. 27. Study of Tc uptake withStudy of Tc uptake with Na oxalateNa oxalate underunder oxidizing and reducing conditionsoxidizing and reducing conditions  Tc(VII) is excluded from the Na oxalate structureTc(VII) is excluded from the Na oxalate structure under oxidizing conditions (Kd = 1-2)under oxidizing conditions (Kd = 1-2)  Under reducing conditions Tc(IV) forms a separateUnder reducing conditions Tc(IV) forms a separate TcOTcO22*1.6H*1.6H22O phase - no interaction between TcO phase - no interaction between Tc hydroxide and Na oxalate were detectedhydroxide and Na oxalate were detected  Tc precipitate is not resistant to leaching with 0.1 NTc precipitate is not resistant to leaching with 0.1 N NaNONaNO22 NaOH + H2C2O4 = Na2C2O4 X-ray diffraction tests : the precipitate is sodium oxalate Na2C2O4 (PDF#20-1149)
  28. 28. Study of Tc uptake withStudy of Tc uptake with Cryolite NaCryolite Na33AlFAlF66 underunder oxidizing and reducing conditionsoxidizing and reducing conditions  Reduced TcReduced Tc ::  17-35% of Tc(IV) as17-35% of Tc(IV) as TcClTcCl66 2-2- is co-is co- precipitated withprecipitated with cryolitecryolite  NN22HH55NONO33 inhibits co-inhibits co- precipitationprecipitation  OxidizingOxidizing conditionsconditions::  Kd is less 1Kd is less 1  Tc(VII) is excludedTc(VII) is excluded from cryolitefrom cryolite structurestructure 6F6F-- +NaAlO+NaAlO22+Na+Na22COCO33 X-ray diffraction tests : the precipitate is cryolite Na3AlF6
  29. 29. Study of Tc(IV) uptakeStudy of Tc(IV) uptake withwith Cryolite NaCryolite Na33AlFAlF66 underunder rreducing conditionseducing conditions No [NH4 F] initial, M [Na2 CO3 ] in final solution, M [N2 H5 NO3 ], in final solution, M Tc(IV) uptake, % 1 2 3 4 5 8 9 10 2,0 2.5 3.0 4,0 6,0 2,0 2,0 2,0 0,6 0.6 0,6 0.6 0,6 0,4 0,8 0,6 - - - - - - - 0,1 20 23 26 28 35 25 17 0 • Tc(IV) is added as NaTc(IV) is added as Na22 TcClTcCl66 to (to (NHNH44F+NaAlOF+NaAlO22)) solutionsolution • No additional reducing agent in exp. No 1-9No additional reducing agent in exp. No 1-9 • Leaching test were impossible to quantifyLeaching test were impossible to quantify
  30. 30. Study of Tc(IV) uptake withStudy of Tc(IV) uptake with FeOOHFeOOH underunder rreducing conditionseducing conditions Precipitation test: Leaching test (t=18 o C, d = days): Leaching yield ,Tc, %NaOH M Tc in solid phase, % Leaching agent: 1 d 10 d 29 d 105d 0.6 97 0.1M NaOH 1.0 9.8 14.9 24 2.0 88.0 1M NaOH 2.9 16.5 40.2 58 4.0 90 2M NaOH 0.8 2 3 8.2  Reducing agent: 0.02M FeSO4, T = 60Reducing agent: 0.02M FeSO4, T = 6000 СС, time = 3 h, time = 3 h  Precipitate : FeOOH/FePrecipitate : FeOOH/Fe22OO33 ThoughThough TcTc adsorbedadsorbed betterbetter on iron hydroxides from 0.5–2.0 M NaOHon iron hydroxides from 0.5–2.0 M NaOH than from 3.0-4.0 M NaOH,than from 3.0-4.0 M NaOH, the precipitates formedthe precipitates formed at lower NaOHat lower NaOH concentration were more easily leached by the NaOH leachantconcentration were more easily leached by the NaOH leachant Tc leaching with H2O2 was 20 % and with Na2S2O8 was70-100% in 100 days
  31. 31. Study of Tc(IV) uptake withStudy of Tc(IV) uptake with MnOOHMnOOH underunder rreducing conditionseducing conditions  Reaction NaOH + NaReaction NaOH + Na22MnOMnO44+ N+ N22HH55OH= MnOOHOH= MnOOH X-ray diffraction tests : the freshly precipitatedX-ray diffraction tests : the freshly precipitated solid was Mnsolid was Mn22OO33 , the aged precipitate was, the aged precipitate was manganite MnOOHmanganite MnOOH (PDF#18-805)(PDF#18-805)  Manganese(III) oxides were effective Tc carriers and underwent chemical transformations on ageing that increased leaching resistance to most agents. 0 2 4 6 8 10 12 0 2 4 6 8 10 12 Time. d LeachedTc,% 1) Mn/Al=1/10 2) Mn/Al=1/40 3)Mn/Al=1/10 4) Mn/Al=1/40 MnOOH precipitation MnOOH leaching to 0.1 NaOH (1,3,4) and Na2S2O8(2) 0 15 30 45 60 75 90 0 5 10 15 20 25 30 Time,d Tcuptakebyprecipitate,% Mn/Al=1/10 Mn/Al=1/40
  32. 32. (a)(a) Al(OH)3 - Aluminum hydroxide - gibbsite ;Al(OH)3 - Aluminum hydroxide - gibbsite ; (b)(b) Boehmite [AlO(OH)] -aluminum oxyhydroxideBoehmite [AlO(OH)] -aluminum oxyhydroxide (c)(c) Al2O3 aluminum oxide - corundAl2O3 aluminum oxide - corund Boehmite and Al-oxyhydroxide gels sorb ReO4Boehmite and Al-oxyhydroxide gels sorb ReO4 a non-radioactivea non-radioactive analogue of TcO4analogue of TcO4 from NaNO3 solutions.Sorption appears to befrom NaNO3 solutions.Sorption appears to be substantially electrostatic (though theresubstantially electrostatic (though there appears to be a specificappears to be a specific preference for ReO4preference for ReO4 over NO3over NO3 andand is most effective at pH = 8.is most effective at pH = 8. Measured Kd’s lie between 5 andMeasured Kd’s lie between 5 and 105 ml g105 ml g--1, depending on the solid,1, depending on the solid, pH, and ionic strength.pH, and ionic strength. ReO4ReO4 and TcO4 are both partially removedand TcO4 are both partially removed from high pHfrom high pH Hanford-type acid waste simulants upon neutralizationHanford-type acid waste simulants upon neutralization and formationand formation of Al-rich sludges. It was proposed that sequestrationof Al-rich sludges. It was proposed that sequestration ofof Tc by boehmite limits dissolved Tc levels in the nearTc by boehmite limits dissolved Tc levels in the near and sub-surfaceand sub-surface environment and for that purpose boehmiteenvironment and for that purpose boehmite might be relied on as amight be relied on as a backfill, or reactive barrier, to limitbackfill, or reactive barrier, to limit environmental transportenvironmental transport of Tc.of Tc. How Mo-Tc generators could do work being made of Al oxide - oxyhydroxide ???How Mo-Tc generators could do work being made of Al oxide - oxyhydroxide ??? Boehmite sorbs perrhenate and pertechnetateBoehmite sorbs perrhenate and pertechnetate By Peng-Chu Zhang*, James L. Krumhansl and Patrick V. BradyBy Peng-Chu Zhang*, James L. Krumhansl and Patrick V. Brady Sandia National Laboratories, Albuquerque, USASandia National Laboratories, Albuquerque, USA Radiochim. Acta 88, 3692373 (2000)Radiochim. Acta 88, 3692373 (2000)
  33. 33. Tc(VII) + STc(VII) + S2-2- 0 2 4 6 8 10 12 14 16 18 20 22 24 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Kinetics of the reaction of pertechnetate with sulfide in 0.3M Na 2 S solution at 22oC [Tc], *104M Tc2.66 Tc1.9 Tc1.52 Tc1.14 Tc0.57 Convertiondegree Time, min  Induction period of the reactionInduction period of the reaction of pertechnetate with Naof pertechnetate with Na22S variesS varies from 4 to 100 minutesfrom 4 to 100 minutes dependingdepending on the concentration of reagents,on the concentration of reagents, pH and TpH and T  Reaction of pertechnetate withReaction of pertechnetate with NaNa22S is completedS is completed within one to tenwithin one to ten hours depending on thehours depending on the concentration of reagentsconcentration of reagents  ReactionReaction is fast if compared tois fast if compared to slowslow TcTc22SS77 ((TcS3,33) sedimentation (undersedimentation (under most conditions) due to colloid formationmost conditions) due to colloid formation  David Shuh, Wayne Lukens, Carol Burns, Final report on Project Number: EMSP-73778, 2004 :
  34. 34. SSeeparationparation ofof TcTc22SS77 colloidcolloideses fromfrom NaNa22SS solutionsolution byby Microfilterfuge (RAININ Instr. Co)Microfilterfuge (RAININ Instr. Co) withwith ultrafiltrationultrafiltration membranesmembranes -- 30000 NMWL30000 NMWL  FormationFormation ofof colloidcolloideses TcTc22SS77 isis ccomplompletedeted inin 50 h50 hoursours underunder thesethese conditionsconditions  [Tc][Tc] in thein the solutionsolutionss at timesat times fromfrom 5050 toto 150 h150 hooursurs corresponds to truecorresponds to true solubilitsolubility ofy of TcTc22SS77 Tc2S7 ultrafiltration 0 0.0001 0.0002 0.0003 0.0004 0.0005 0.0006 0.0007 0 25 50 75 100 125 150 175 200 TIME, H C(Tc),M/L 0.46M 0.33M 0.2M 0.13M 0.066M 0.033M 0.02M [Na2S] Solubility Tc2S7 in Na2S solutions C(Tc) = -9E-05Ln[Na2S] - 2E-05 R 2 = 0.9917 0 0.00005 0.0001 0.00015 0.0002 0.00025 0.0003 0.00035 0 0.1 0.2 0.3 0.4 0.5 [Na2S], M/L C(Tc),M/L 0 20000 40000 60000 80000 100000 120000 140000 0 50 100 150 200 250 300 350 400 450 Time, hours A,cpm 0.46M 0.33M 0.2M 0.13M 0.066M 0.033M 0.02M Sedimentation of colloides Tc2S7 [Na2S]
  35. 35. The reduction of Tc(VII) to Tc(V,IV,III ) byThe reduction of Tc(VII) to Tc(V,IV,III ) by abiotic and biotic processesabiotic and biotic processes The reduction of Tc(VII) to Tc(IV) by abiotic and biotic processes has recentlyThe reduction of Tc(VII) to Tc(IV) by abiotic and biotic processes has recently been the subject of extensive studies because it has a significant effect onbeen the subject of extensive studies because it has a significant effect on the mobility of technetium in waste streams, vadose zones, sediments, andthe mobility of technetium in waste streams, vadose zones, sediments, and groundwater. These reaction processes are the basis for certaingroundwater. These reaction processes are the basis for certain remediationtechnologies such as permeable barriers composed of zero-remediationtechnologies such as permeable barriers composed of zero- valent iron particles (i.e., as metallic iron) or sodium-dithionite reduced soils,valent iron particles (i.e., as metallic iron) or sodium-dithionite reduced soils, which are being tested for immobilization of groundwater contaminants.which are being tested for immobilization of groundwater contaminants.
  36. 36. Transmutation target :Transmutation target : Tc/Ru recoveryTc/Ru recovery Tc-Ru acidic and pyrochemical solubilizationTc-Ru acidic and pyrochemical solubilization problemproblem N. Schroeder approach : homogeneous transmutation
  37. 37. Microbial reduction of Tc(VII)Microbial reduction of Tc(VII)  Microbial reduction of Tc(VII) has been suggested as a potential mechanismMicrobial reduction of Tc(VII) has been suggested as a potential mechanism for removing technetium from contaminated groundwaters and wastefor removing technetium from contaminated groundwaters and waste streams (e.g., Lovley 1993, 1995, Lyalikova,German et all. 1994).streams (e.g., Lovley 1993, 1995, Lyalikova,German et all. 1994).  Certain dissimilatory metal reducing bacteria and sulfate reducing bacteriaCertain dissimilatory metal reducing bacteria and sulfate reducing bacteria have been determined to be capable of coupling the oxidation of organichave been determined to be capable of coupling the oxidation of organic carbon or hydrogen to the reduction of Tc(VII) to Tc(IV)carbon or hydrogen to the reduction of Tc(VII) to Tc(IV)  Lyakikova,German,Khizhnyak , Peretrukhin 1994 , 1998,Lyakikova,German,Khizhnyak , Peretrukhin 1994 , 1998,  Gavrilov, German et all. 2007 ,Gavrilov, German et all. 2007 ,  Lloyd and Macaskie 1996;Lloyd and Macaskie 1996;  Lloyd et al. 1997, 1998, 1999, 2000a,b;Lloyd et al. 1997, 1998, 1999, 2000a,b;  Wildung et al. 2000;Wildung et al. 2000;  Fredrickson et al. 2000).Fredrickson et al. 2000).
  38. 38. Reduction of pertechnetate by haloalkaliphilic strainsReduction of pertechnetate by haloalkaliphilic strains of Halomonasof Halomonas Tatiana KhijniakTatiana Khijniak , Natalia Medvedeva-Lyalikova, Monique Simonoff, Natalia Medvedeva-Lyalikova, Monique Simonoff Microbiology Ecology – 2003/44Microbiology Ecology – 2003/44 It was shown by Khizhniak , 2003 thatIt was shown by Khizhniak , 2003 that haloalkaliphilic bacteriahaloalkaliphilic bacteria, isolated from, isolated from soda-lake environmentssoda-lake environments were capable of reducing Tc(VII)Owere capable of reducing Tc(VII)O44 −− to the Tc(V), Tc(IV)to the Tc(V), Tc(IV) andand Tc(III)Tc(III) at pH 10 in carbonate medium, whereas no reduction took placeat pH 10 in carbonate medium, whereas no reduction took place without bacteria or in the presence of dead biomass.without bacteria or in the presence of dead biomass. After 34 h of incubation, 55% remained as Tc(VII), 36% was found as Tc(IV) andAfter 34 h of incubation, 55% remained as Tc(VII), 36% was found as Tc(IV) and 8% as Tc(V) and after 2 months 80% of the technetium was reduced.8% as Tc(V) and after 2 months 80% of the technetium was reduced. Technetium had a toxic effect on bacteria. Reduction of TcOTechnetium had a toxic effect on bacteria. Reduction of TcO44 −− was drasticallywas drastically decreased at concentration above 1.5 mM.decreased at concentration above 1.5 mM. The microbial reduction has been suggested as a potential mechanism for theThe microbial reduction has been suggested as a potential mechanism for the removal of Tc from contaminated environments or waste streams.removal of Tc from contaminated environments or waste streams. Thermophilic :Thermophilic : fresh water crenarchaeonfresh water crenarchaeon Pyrobaculum islandicumPyrobaculum islandicum (Kashefi and Lovley(Kashefi and Lovley 2000) ,2000) , Last year we demonstrated that thermophilic representatives of both prokaryoticLast year we demonstrated that thermophilic representatives of both prokaryotic domains—Bacteria and Archaea, inhabiting marine and freshwater hydrothermaldomains—Bacteria and Archaea, inhabiting marine and freshwater hydrothermal
  39. 39. Characterization of technetium(VII) reduction by cellCharacterization of technetium(VII) reduction by cell suspensions of thermophilic bacteria and archaeasuspensions of thermophilic bacteria and archaea N. Chernyh , S. Gavrilov, V. Sorokin & K. German …N. Chernyh , S. Gavrilov, V. Sorokin & K. German … Appl Microbiol Biotechnol (2007) 76:467–472Appl Microbiol Biotechnol (2007) 76:467–472 Washed cell suspensions of the anaerobic hyperthermophilic archaea Thermococcus pacificus (a) and Thermoproteusuzoniensis (b) (both at 85o C ) and the anaerobic thermophilic gram-positive bacteria Thermoterrabacterium ferrireducens ( c , at 65o C ) and Tepidibacter thalassicus (d, at 50o C ) reduced technetium [99Tc(VII)], supplied as soluble pertechnetate with molecular hydrogen as an electron donor, forming highly insoluble Tc(IV)-containing grayish-black precipitate.
  40. 40. Thank you for your Attention !Thank you for your Attention !
  41. 41. Masataka Ogawa (1865 - 1930)

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