000852442 001__ 852442
000852442 005__ 20240708134001.0
000852442 037__ $$aFZJ-2018-05388
000852442 1001_ $$0P:(DE-Juel1)144040$$aBrandt, Felix$$b0$$eCorresponding author$$ufzj
000852442 1112_ $$aGoldschmidt$$cBoston$$d2018-08-12 - 2018-08-17$$wUSA
000852442 245__ $$aRa Uptake by the Sr-Rich Solid Solution of (Sr, Ba)SO4
000852442 260__ $$c2018
000852442 3367_ $$033$$2EndNote$$aConference Paper
000852442 3367_ $$2DataCite$$aOther
000852442 3367_ $$2BibTeX$$aINPROCEEDINGS
000852442 3367_ $$2DRIVER$$aconferenceObject
000852442 3367_ $$2ORCID$$aLECTURE_SPEECH
000852442 3367_ $$0PUB:(DE-HGF)6$$2PUB:(DE-HGF)$$aConference Presentation$$bconf$$mconf$$s1537347937_29575$$xOther
000852442 520__ $$aSolid  solution  formation  is  an  important  mechanism  of radionuclide  uptake  by  mineral  phases  which  is  favored  in natural  systems  due  to  a  lowered  configurational  entropy. Recent    studies    have    shown    that    the   formationof   a (Ba,Ra)SO4 solid solution significantly reduces the solubility of 226Ra  in  aqueous  systems.  This  result  is  very  relevant  for the  direct  disposal  of  spent  nuclear  fuel  in  a  deep  geological formation,   where 226Ra   would   dominate   the   dose   after 100,000  years  [1].  In  natural  systems SrSO4  often  occurs along   with   BaSO4   implying   that Ra-uptake   should   be assessed within the system of (Sr,Ba,Ra)SO4 + H2O. A recent thermodynamic  modelling  study  [2]  predicted  a  significant uptake of Ra into the ternary (Sr,Ba,Ra)SO4 solid-solution.  Here we present results     of long-term     batch-recristallisation experiments on Ra-uptake in a Sr-rich part of the  ternary  system.  A  mechanical  mixture  of  celestite  with a small  amount  of  barite  and  a  (Sr,Ba)SO4  solid  solution  of equivalent   comoposition   were   put   into a contact   with 226Ra,aq.  We  observed a  significant  uptake  of 226Ra  in  both cases  proceeding  via  the  formation  of  the  minor  ternary Sr-, Ba-  and  Ra-rich  phase  within  the  major  Sr-rich  phase.  In longer  experiments  the  ternary  phase  disappeared  leading  to the  formation  of  a  mixture  of  Sr-  and  Ba-rich  phases,  within which  Ra  could  not  be  detected by  scanning  transmission electron   microscopy-energy-dispersive   X-ray   spetroscopy (STEM-EDX). The   final 226Ra   concentrations   in   both experiments  were  similar  and  close  to  predicted  levels.  The formation  of  the  intermediate  phase  is  interpreted  based  on structural and kinetic considerations. [1]  Norrby,  S.  et  al.  (1997).  “SKI  SITE-94 Saekerhetsanalys  foer  Djupfoervar  iett  Kristallint  berg”.Stockholm,  Sweden.  [2]  Vinograd  et  al.  (2018).  Applied Geochemistry, in press.
000852442 536__ $$0G:(DE-HGF)POF3-161$$a161 - Nuclear Waste Management (POF3-161)$$cPOF3-161$$fPOF III$$x0
000852442 7001_ $$0P:(DE-Juel1)130364$$aKlinkenberg, Martina$$b1$$ufzj
000852442 7001_ $$0P:(DE-Juel1)169154$$aPoonoosamy, Jenna$$b2$$ufzj
000852442 7001_ $$0P:(DE-Juel1)130525$$aBarthel, Juri$$b3$$ufzj
000852442 7001_ $$0P:(DE-Juel1)157607$$aWeber, Juliane$$b4
000852442 7001_ $$0P:(DE-Juel1)130324$$aBosbach, Dirk$$b5$$ufzj
000852442 909CO $$ooai:juser.fz-juelich.de:852442$$pVDB
000852442 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)144040$$aForschungszentrum Jülich$$b0$$kFZJ
000852442 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)130364$$aForschungszentrum Jülich$$b1$$kFZJ
000852442 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)169154$$aForschungszentrum Jülich$$b2$$kFZJ
000852442 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)130525$$aForschungszentrum Jülich$$b3$$kFZJ
000852442 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)130324$$aForschungszentrum Jülich$$b5$$kFZJ
000852442 9131_ $$0G:(DE-HGF)POF3-161$$1G:(DE-HGF)POF3-160$$2G:(DE-HGF)POF3-100$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bEnergie$$lNukleare Entsorgung und Sicherheit sowie Strahlenforschung$$vNuclear Waste Management$$x0
000852442 9141_ $$y2018
000852442 9201_ $$0I:(DE-Juel1)IEK-6-20101013$$kIEK-6$$lNukleare Entsorgung und Reaktorsicherheit$$x0
000852442 9201_ $$0I:(DE-Juel1)ER-C-2-20170209$$kER-C-2$$lMaterialwissenschaft u. Werkstofftechnik$$x1
000852442 980__ $$aconf
000852442 980__ $$aVDB
000852442 980__ $$aI:(DE-Juel1)IEK-6-20101013
000852442 980__ $$aI:(DE-Juel1)ER-C-2-20170209
000852442 980__ $$aUNRESTRICTED
000852442 981__ $$aI:(DE-Juel1)IFN-2-20101013