Solubility Constraint: An Important Consideration in Safety Assessment of Nuclear Waste Disposal

1983 ◽  
Vol 26 ◽  
Author(s):  
Dhanpat Rai ◽  
Jack L. Ryan
Keyword(s):  
Nuclear Waste ◽  
Safety Assessment ◽  
Additional Data ◽  
Solid Phase ◽  
Waste Form ◽  
Waste Package ◽  
Reducing Conditions ◽  
Solid Compounds ◽  
Adsorption Desorption ◽  
Hydrologic Transport

ABSTRACTSolubilities of key solid compounds that are either present in the waste form or can readily precipitate from waste package leachates under repository conditions can be used to set maximum limits on radionuclide concentrations expected in groundwater. This is because the solubility limited concentrations are independent of the release scenarios, hydrologic transport characteristics, and adsorption/desorption reactions. Some of the important factors that control solubilities are pH, pe, type of solid phase, and nature of complexing ligands in the ground waters. Most of the above factors are affected by radiolysis due to the inherent radiation field of the waste form. Experimental results pertaining to the solubilities of selected Am, U, Np, and Pu compounds and the effects of radiolysis are discussed. These results show that: 1) at expected repository pH and reducing conditions, solubility controlled concentrations of several actinides are low and near acceptable limits, 2) the redox conditions at the waste form-water interface may be very oxidizing due to radiolyticeffects, despite the fact that normal repository conditions are assumed to be reducing, 3) additional data on solubility limits and key thermodynamic parameters are needed.

Materials Interactions Relating to Long-Term Geologic Disposal of Nuclear Waste Glass

1986 ◽  
Vol 84 ◽  
Author(s):  
Ned E. Bibler ◽  
Carol M. Jantzen
Keyword(s):  
Nuclear Waste ◽  
Review Paper ◽  
Waste Glass ◽  
Waste Form ◽  
Glass Waste ◽  
Waste Package ◽  
Geologic Disposal ◽  
Nuclear Waste Glass ◽  
Backfill Materials

AbstractIn the geologic disposal of nuclear waste glass, the glass will eventually interact with groundwater in the repository system. Interactions can also occur between the glass and other waste package materials that are present. These include the steel canister that holds the glass, the metal overpack over the canister, backfill materials that may be used, and the repository host rock. This review paper systematizes the additional interactions that materials in the waste package will impose on the borosilicate glass waste form-groundwater interactions. The repository geologies reviewed are tuff, salt, basalt, and granite. The interactions emphasized are those appropriate to conditions expected after repository closure, e.g. oxic vs. anoxic conditions. Whenever possible, the effect of radiation from the waste form on the interactions is examined. The interactions are evaluated based on their effect on the release and speciation of various elements including radionuclides from the glass. It is noted when further tests of repository interactions are needed before long-term predictions can be made.

Phase evolution in [Nd1-xUx]2Zr2O7+δ system in oxidizing and reducing conditions: A nuclear waste form

2021 ◽  
pp. 153208
Author(s):  
Chiranjit Nandi ◽  
Rohan Phatak ◽  
Swayam Kesari ◽  
Muhammed Shafeeq ◽  
Rekha Rao ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Phase Evolution ◽  
Waste Form ◽  
Reducing Conditions

scholarly journals Methods of Simulating Low Redox Potential (Eh) for a Basalt Repository

1983 ◽  
Vol 26 ◽  
Author(s):  
Carol M. Jantzen
Keyword(s):  
Redox Potential ◽  
Nuclear Waste ◽  
Deionized Water ◽  
Waste Form ◽  
Laboratory Simulation ◽  
Redox Potentials ◽  
Waste Package ◽  
Leach Rate ◽  
Ph Conditions ◽  
Selection Of

ABSTRACTIn the selection of a repository for burying vitrified nuclear waste, the leach rate of the waste form in groundwater is of concern. Basaltic groundwaters have inherently low redox potentials which may affect the waste form leach rate. Laboratory simulation of the Eh-pH conditions to be found in a basalt repository can be achieved when crushed basalt is added to deoxygenated deionized water. The effects of other redoxactive waste package components, such as iron, were found to stabilize solution redox potential at different valves under oxic and anoxic conditions. When iron was present, different waste form leach rates were observed with and without oxygen.

Investigation of the Hydrothermal Interaction of 99Tc-Doped Glass with Basalt Repository Nuclear Waste Package Components

1984 ◽  
Vol 44 ◽  
Author(s):  
David G. Coles ◽  
S. A. Simonson ◽  
L. E. Thomas ◽  
J. A. Schranke ◽  
S. G. McKinley
Keyword(s):  
Nuclear Waste ◽  
Solid Phase ◽  
Synergistic Effects ◽  
Secondary Phase ◽  
Solution Concentration ◽  
Waste Package ◽  
Glass Dissolution ◽  
Hydrothermal Experiments ◽  
Solid Phases ◽  
Doped Glass

AbstractHydrothermal experiments using basalt-repository nuclear waste package components have been carried out at 200°C and 30 MPa using 99Tc-doped PNL 76–68 waste glass. This work was conducted in support of the Basalt Waste Isolation Project. The experiments were carried out in rocking autoclaves that allowed for periodic solution sampling. Preliminary results that illustrated the effect of basalt on 99Tc solution behavior were discussed previously[l]. In this paper, we continue those observations by discussing the additional experiments that investigated the effects of steel. We also include the post-experiment solid phase analyses from all test configurations.The effect of steel on glass dissolution was observed to be minimal when basalt was not present, i.e., there were no discernible differences in the amount of glass dissolved (based on boron release), with or without steel present.The 99Tc solution concentration results showed that basalt, steel, and a combination of basalt and steel have an ability to dramatically lower the concentration of 99Tc in the solution, probably through a redox mechanism[2]. Solid run product analyses showed that without basalt present, a gel-like secondary phase consisting of an iron, zinc clay with an apparent smectite structure formed. When basalt was present clinoptilolite formed as the major secondary phase, due primarily to the presence of aluminum in the basalt mesostasis. Separation of the various solid run products and residual initial solid phases has not yet been achieved. Such a separation would facilitate the identification of the phase or phases with which 99Tc was associated. The solution results indicated that 99Tc, a potentially mobile radionuclide, may be incorporated in a relatively insoluble phase in the environment of a basalt repository. In addition, no synergistic effects between waste package components were observed that would increase the concentration of 99Tc in solution.

Methodology of Research in Micropollutants – Heavy Metals

1982 ◽  
Vol 14 (12) ◽  
pp. 107-125 ◽  
Author(s):  
Roland Wollast
Keyword(s):  
Heavy Metals ◽  
Mathematical Models ◽  
Aqueous Phase ◽  
Suspended Matter ◽  
Solid Phase ◽  
Aquatic Organisms ◽  
Biological Processes ◽  
Particulate Phase ◽  
Sources Of Pollution ◽  
Adsorption Desorption

A comparison of the concentration of dissolved and of particulate heavy metals in the aquatic system indicates that these elements are strongly enriched in the suspended matter. The transfer between the aqueous phase and the solid phase may be due to dissolution-precipitation reactions, adsorption-desorption processes or biological processes. When these processes are identified, it is further possible to develop mathematical models which describe the behaviour of these elements. The enrichment of heavy metals in the particulate phase suspended or deposited and in aquatic organisms constitutes a powerful tool in order to evaluate sources of pollution.

scholarly journals Adsorption Capacity and Selectivity of Molecularly Imprinted Polymers towards β-Sitosterol

2019 ◽  
Vol 31 (11) ◽  
pp. 2527-2531
Author(s):  
St. Fauziah ◽  
N.H. Soekamto ◽  
P. Budi ◽  
P. Taba
Keyword(s):  
Adsorption Capacity ◽  
Molecularly Imprinted Polymers ◽  
Solid Phase ◽  
Polymerization Reaction ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Sample Extract ◽  
Uv Visible ◽  
Adsorption Desorption ◽  
Isothermal Equation

Molecularly imprinted polymers (MIP) as an adsorbent has been synthesized using β-sitosterol as molecule template on free radical polymerization reaction. The capacity and selectivity of the adsorption from MIP to β-sitosterol was studied in this study. The β-sitosterol concentration in the adsorption-desorption test and the MIP selectivity test were analyzed by UV-visible and HPLC. The MIP obtained from the synthesis results in a high adsorption capacity. Based on the Freundlich adsorption isothermal equation, the adsorption capacity (k) was found to be 1.24 mg/g. The MIP can adsorb 100 % β-sitosterol while cholesterol was only 3 %. The MIP is most selective to β-sitosterol, therefore, has high potential to apply as adsorbent at solid phase extraction method to isolate β-sitosterol from sample extract.

Pools and Fluxes of Organic Matter in a Boreal Landscape: Implications for a Safety Assessment of a Repository for Nuclear Waste

AMBIO ◽  
2006 ◽  
Vol 35 (8) ◽  
pp. 496-504 ◽  
Author(s):  
Linda Kumblad ◽  
Björn Söderbäck ◽  
Anders Löfgren ◽  
Tobias Lindborg ◽  
Erik Wijnbladh ◽  
...  
Keyword(s):  
Organic Matter ◽  
Nuclear Waste ◽  
Safety Assessment ◽  
Boreal Landscape
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