TY - JOUR
T1 - Interaction between spent fuel components and carbonate rocks
AU - Klein-BenDavid, O.
AU - Harlavan, Y.
AU - Levkov, I.
AU - Teutsch, N.
AU - Brown, K. G.
AU - Gruber, C.
AU - Ganor, J.
N1 - Funding Information:
We would like to thank the TAGAR administration at the Ministry of Energy, Israel for funding this research, number 213-11-026 . We would also like to thank Ms. Emily Tran for constructive discussions and English editing.
Publisher Copyright:
© 2019
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Deep geological repository is considered the internationally accepted method for spent fuel (SF) disposal. In countries where salt, clay, tuff and granite are unavailable at geologically suitable area, other rock types may come into consideration. In Israel, carbonate rocks make up a significant portion of the surface and subsurface lithologies, thus, low permeability carbonates were evaluated as possible host rocks for a repository, and for an interim storage facility. Sorption and retardation capacity of SF components to low permeability carbonate rocks were evaluated using their chemical simulants. Strontium and Cs represent components that may leach during interim storage, while U and Ce (as a simulant for redox-active actinides) represent components that may leach under repository conditions. Rocks from the Upper Cretaceous Mount Scopus Group were sampled from boreholes at the Yamin Plateau, Israel. Single point batch experiments were conducted with synthetic rainwater spiked with tracers and interacted with five rock types of various particle sizes at 25 °C. Results were evaluated using the LeachXS™-ORCHESTRA geochemical speciation and data management program. Cerium removal was found to be related to the HCO3 – concentration in solution, where Ce precipitated as Ce2(CO3)3·XH2O and as an amorphous carbonate phase. Removal of Cs and Sr was controlled by clays. No Sr co-precipitation as carbonate species was observed. Uranium was removed mainly by sorption onto solid organic matter, whereas clays had no significant role in U sorption. Iron-(hydr) oxides may have also played a role in U removal. Calculated partition coefficients for U, Cs, and Sr were in the order of 101–102 mL/g. Grain size had no significant effect on the retention capacity of the studied rocks due to similar effective surface area. The current study indicates that a repository or an interim storage facility within carbonate rocks, would provide only partial isolation of radionuclides from the environment, hence, additional engineered barriers may be required.
AB - Deep geological repository is considered the internationally accepted method for spent fuel (SF) disposal. In countries where salt, clay, tuff and granite are unavailable at geologically suitable area, other rock types may come into consideration. In Israel, carbonate rocks make up a significant portion of the surface and subsurface lithologies, thus, low permeability carbonates were evaluated as possible host rocks for a repository, and for an interim storage facility. Sorption and retardation capacity of SF components to low permeability carbonate rocks were evaluated using their chemical simulants. Strontium and Cs represent components that may leach during interim storage, while U and Ce (as a simulant for redox-active actinides) represent components that may leach under repository conditions. Rocks from the Upper Cretaceous Mount Scopus Group were sampled from boreholes at the Yamin Plateau, Israel. Single point batch experiments were conducted with synthetic rainwater spiked with tracers and interacted with five rock types of various particle sizes at 25 °C. Results were evaluated using the LeachXS™-ORCHESTRA geochemical speciation and data management program. Cerium removal was found to be related to the HCO3 – concentration in solution, where Ce precipitated as Ce2(CO3)3·XH2O and as an amorphous carbonate phase. Removal of Cs and Sr was controlled by clays. No Sr co-precipitation as carbonate species was observed. Uranium was removed mainly by sorption onto solid organic matter, whereas clays had no significant role in U sorption. Iron-(hydr) oxides may have also played a role in U removal. Calculated partition coefficients for U, Cs, and Sr were in the order of 101–102 mL/g. Grain size had no significant effect on the retention capacity of the studied rocks due to similar effective surface area. The current study indicates that a repository or an interim storage facility within carbonate rocks, would provide only partial isolation of radionuclides from the environment, hence, additional engineered barriers may be required.
KW - Carbonate
KW - Deep geological repository
KW - Interim storage
KW - Spent fuel
UR - http://www.scopus.com/inward/record.url?scp=85068213458&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2019.06.396
DO - 10.1016/j.scitotenv.2019.06.396
M3 - Article
C2 - 31279194
AN - SCOPUS:85068213458
SN - 0048-9697
VL - 689
SP - 469
EP - 480
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -