VESPA Behaviour of Long-Lived Fission and Activation Products in the Nearfield of a Nuclear

757 Pages·2016·13.7 MB·English

VESPA
Behaviour of
Long-Lived Fission and
Activation Products
in the Nearfeld of a
Nuclear Waste Repository
and the Possibilities of
their Retention
Conducted by:
Karlsruhe Institute of Technology
GRS - 374
Gesellschaft für Anlagen-
und Reaktorsicherheit
(GRS) gGmbH
VESPA
Behaviour of
Long-Lived Fission and
Activation Products
in the Nearfeld of a
Nuclear Waste Repository
and the Possibilities of
their Retention
Barbara Bischofer (GRS),
Sven Hagemann (GRS),
Marcus Altmaier, Nidhu Banik (KIT),
Dirk Bosbach (FZJ),
Guido Bracke (GRS),
Vinzenz Brendler (HZDR),
Hildegard Curtius (FZJ),
Nicolas Finck (KIT),
Carola Franzen (HZDR),
Xavier Gaona, Horst Geckeis (KIT),
Frank Heberling, Michel Herm (KIT),
Jonathan Kindlein (GRS),
Remi Marsac, Volker Metz (KIT),
Andrés Muñoz (GRS),
Konstantin Rozov (FZJ),
Thorsten Schäfer (KIT),
Tina Scharge (GRS),
Yuri Totskiy, Martin Wiedemann (KIT),
Ezgi Yalcintas (KIT)
June 2016
Remark:
The underlying work of this report
was supported under contract No.
02E10770, 02E10780, 02E10790
and 02E10800 by the German
Federal Ministry of Economics and
Energy (BMWi).
The work was conducted by the
Gesellschaft für Anlagen- und
Reaktorsicherheit (GRS) gGmbH,
Forschungszentrum Jülich GmbH
(FZJ), Helmholtz-Zentrum Dresden-
Rossendorf e.V. (HZDR) and Karls-
ruher Institut für Technologie (KIT).
The authors are responsible for the
content of this report.
GRS - 374
ISBN 978-3-944161-55-6
Keywords:
repository, radionuclides, modelling, sorption, solubility
Foreword
The present document is the final report of the Joint Research Project VESPA (Beha-
viour of Long-lived Fission and Activation Products in the Near Field of a Nuclear
Waste Repository and the Possibilities of Their Retention), started in July 2010 with a
duration of four years. The following four institutions were collaborative Partners in
VESPA:
 Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH
 Institut für Energie- und Klimaforschung, IEK-6: Nukleare Entsorgung und Re-
aktorsicherheit, Forschungszentrum Jülich (FZJ)
 Institut für Ressourcenökologie (IRE), Helmholtz-Zentrum Dresden-Rossendorf
(HZDR)
 Institut für Nukleare Entsorgung (INE), Karlsruher Institut für Technologie (KIT)
VESPA was funded by the German Federal Ministry of Economics and Energy (BMWi)
under the contract numbers 02 E 10770 (GRS), 02 E 10780 (FZJ-IEF-6), 02 E 10790
(HZDR-IRE), 02 E 10800 (KIT-INE).
The chapters within this report have been prepared by the following authors and institu-
tions:
 Chapter 4: HZDR-IRE: Carola Franzen, Norbert Jordan, Vinzenz Brendler
 Chapter 5: KIT-INE: Marcus Altmaier, Nidhu Banik, Nicolas Finck, Xavier
Gaona, Frank Heberling, Michel Herm, Remi Marsac, Volker Metz, Thorsten
Schäfer, Yuri Totskiy, Martin Wiedemann, Ezgi Yalcintas, Horst Geckeis
 Chapter 6: FZJ-IEK-6: Hildegard Curtius, Konstantin Rozov, Dirk Bosbach
 Chapter 7: GRS: Barbara Bischofer, Sven Hagemann, Guido Bracke, Jonathan
Kindlein, Andrés Muñoz, Tina Scharge
I
Table of Contents
1 Einleitung ................................................................................................... 1
2 Zusammenfassung ................................................................................... 5
14
2.1 Chemische Bindungsform und Freisetzung von C in radioaktiven
Abfällen ....................................................................................................... 5
14
2.2 Analytische Arbeiten zur Bestimmung der Speziation von C .................... 6
2.3 Chemische Thermodynamik der Spaltprodukte Selen, Iod und
Cäsium ........................................................................................................ 6
2.4 Aquatische Chemie und Thermodynamik von Tc(IV) .................................. 8
2.5 Reduktion, Sorption und Einbau von Tc(VII) in Magnetit ............................ 8
2.6 Einfluss der Reduktionskinetik auf die Tc-Migration in natürlichen
Systemen .................................................................................................... 9
2.7 Struktureller Einbau von Selen in Mineralphasen (Calcit, Pyrit) ................ 10
2.8 Kopräzipitation und Adsorption von Selen an FeS/FeS2 ........................... 11
2.9 Sorption von Selenit und Selenat an endlagerrelevanten
Mineralphasen ........................................................................................... 12
129
2.10 Synthese von Sorelphasen für die Untersuchung der I
Rückhaltung .............................................................................................. 13
2.11 Synthese, Charakterisierung und Langzeitstabilität von LDH-
Mischkristallen ........................................................................................... 14
2.12 Bestimmung der Löslichkeitskonstanten von LDH-Mischkristallen ........... 15
2.13 Rückhaltung anionischer Radionuklidspezies an den modifizierten
LDHs ......................................................................................................... 16
2.14 Methodische Weiterentwicklung von Redoxmessungen bei hohen
Temperaturen und Salinitäten ................................................................... 17
2.15 Berücksichtigung der Ergebnisse in Ausbreitungsmodellen der
Langzeitsicherheitsanalyse ....................................................................... 17
2.16 Resümee ................................................................................................... 18
3 Introduction ............................................................................................. 21
III
3.1 References (chapters 1 – 3) ...................................................................... 24
4 Aqueous speciation and sorption of selenium .................................... 27
4.1 Relevance and context .............................................................................. 27
4.2 Se aqueous chemistry ............................................................................... 35
4.3 Mineral phases characterization ............................................................... 45
4.4 Sorption of Se(VI) and Se(IV) onto mineral phases .................................. 58
4.5 Spectroscopic elucidation of Se(VI) and Se(IV) sorption and redox
processes .................................................................................................. 77
4.6 Surface Complexation Modeling of Se(VI) and Se(IV) sorption
processes ................................................................................................ 121
4.7 Sorption of Se(−II) onto mineral phases .................................................. 128
4.8 Implications on Se mobility in the context of nuclear waste disposals .... 132
4.9 Perspectives ............................................................................................ 135
4.10 Dissemination of results .......................................................................... 138
4.11 References (chapter 4) ........................................................................... 141
5 Redox behaviour, solubility, speciation and incorporation of Tc,
14
Se and C .............................................................................................. 173
5.1 Introduction ............................................................................................. 173
5.2 Redox behaviour of Tc(VII)/Tc(IV) in dilute to concentrated saline
systems ................................................................................................... 174
5.3 The solubility of Tc(IV) in dilute to concentrated NaCl, MgCl2 and
CaCl2 systems ......................................................................................... 206
5.4 Influence of the reduction kinetics on the Tc migration in natural
systems ................................................................................................... 224
5.5 Incorporation of selenium in iron sulfide and calcite................................ 273
14
5.6 Studies on C speciation, Tc uptake by Fe(II) phases and synthesis
of Mg-oxychloride phases ....................................................................... 337
5.7 Summary ................................................................................................. 365
IV
5.8 Contributions at conferences and workshops, and articles in peer-
reviewed journals resulting from work performed by KIT-INE ................. 371
5.9 References (chapter 5) ........................................................................... 377
6 Solid solutions of layered double hydroxides (LDHs) ─
Synthesis, structural/thermodynamic description and their
retention potential for iodide, pertechnetate and selenite ................ 401
6.1 Introduction ............................................................................................. 401
6.2 Objective of this study ............................................................................. 403
6.3 State of the art about layered double hydroxides (LDHs) and their
-
retention potential for iodide (I-), pertechnetate (TcO4 ) and selenite
2-
(SeO3 ) ................................................................................................... 404
6.4 Layered Double Hydroxides .................................................................... 412
6.5 Experimental ........................................................................................... 425
6.6 Results and Discussion ........................................................................... 435
6.7 Conclusion .............................................................................................. 479
6.8 Implication for radioactive waste disposal ............................................... 481
6.9 Future work ............................................................................................. 483
6.10 References (chapter 6) ........................................................................... 484
7 Occurrence, thermodynamic properties and migration of fission
products in the near-field of a repository system .............................. 495
7.1 Thermodynamic properties of aqueous solutions containing iodide,
selenite, selenate and caesium ............................................................... 495
7.2 Solubility of some partly substituted hydrotalcites ................................... 549
7.3 Model for redox measurements in saline solutions ................................. 556
7.4 Occurrence of C-14 in spent fuel............................................................. 570
7.5 Comparative long-term safety calculations ............................................. 591
7.6 References (chapter 7) ........................................................................... 600
8 Summary ................................................................................................ 619
V
14
8.1 Chemical bonding type and release of C in radioactive wastes ........... 619
14
8.2 Analytical studies on C speciation ........................................................ 619
8.3 Chemical thermodynamics of the Fission products selenium, iodine
und caesium ............................................................................................ 620
8.4 Aquatic chemistry, redox transformations and thermodynamics of
Tc(IV) ...................................................................................................... 622
8.5 Reduction, sorption and incorporation of Tc(VII) in magnetite ................ 623
8.6 Influence of redox kinetics on Tc migration in natural systems ............... 623
8.7 Structural incorporation of selenium into mineral phases (calcite,
pyrite) ...................................................................................................... 624
8.8 Co-precipitation and adsorption of selenium on FeS/FeS2 ..................... 626
8.9 Sorption of selenite and selenate onto repository-relevant mineral
phases ..................................................................................................... 627
8.10 Synthesis of Sorel phases as starting material for investigations on
129
I retention ............................................................................................ 628
8.11 Synthesis, characterization and long-term stability of LDH solid
solutions .................................................................................................. 628
8.12 Determination of solubility constant of LDH solid solutions ..................... 630
8.13 Retention of anionic radionuclide species by LDH solid solutions .......... 630
8.14 Methodical advancement of redox measurements at high
temperatures and salinities ..................................................................... 631
8.15 Implementation of the research results into migration models used
within long-term safety assessments ...................................................... 632
8.16 Conclusion .............................................................................................. 632
List of tables .............................................................................................................. 635
List of figures ............................................................................................................ 647
Acronyms and Abbreviations .................................................................................. 675
A Appendix A (chapter 4) ......................................................................... 679
A.1 Se aqueous chemistry ............................................................................. 679
VI