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.

237Np aND 239Pu Solution Behavior During Hydrothermal Testing of Simulated Nuclear Waste Glass with Basalt and Steel

1984 ◽  
Vol 44 ◽  
Author(s):  
Janet A. Schramke ◽  
Scott A. Simonson ◽  
David G. Coles
Keyword(s):  
Nuclear Waste ◽  
Cast Steel ◽  
Size Fraction ◽  
Weight Ratio ◽  
Reaction Products ◽  
Solid Materials ◽  
Solution Behavior ◽  
Waste Package ◽  
Hydrothermal Experiments ◽  
Nuclear Waste Glass

AbstractA series of hydrothermal experiments were carried out on 237Np- and 239Pu-doped PNL 76–68 glass, synthetic basalt groundwater, basalt, and cast steel. These hydrothermal experiments are part of the Basalt Waste Isolation Project investigation of the interactions of waste package components in a basalt repository. Experiments of three months duration were conducted in Dickson-type rocking autoclaves at 200°C and 30 MPa, with an initial fluid to solid weight ratio of 10:1. All solid materials were ground and sieved to a narrow size fraction. The experiments carried out were: glass and groundwater; glass, basalt, and groundwater; glass, steel, and groundwater; and glass, steel, basalt, and groundwater. Unfiltered, 4000 Â filtered, and 18 Å filtered solutions were analyzed to determine the concentrations of radionuclides in solution and those associated with colloids.The quantities of 237Np and 239Pu in solution were very small. Worstcase calculations indicate that 0.01% or less of the total radionuclide inventories were present in solution. The highest solution concentrations of the actinide dopants were observed in the experiments with basalt, even though smaller amounts of glass were dissolved than in the experiments without basalt. The observed differences in the solution concentrations of 237Np and 239Pu were probably controlled by differences in the reaction products, which were clinoptilolite in the experiments with basalt, and an Fe-Zn smectite clay in the experiments without basalt.

The Interaction of Na-Al-P-Glass (Cs, Sr-Bearing) with Water at Elevated Temperatures (70–250°C)

1994 ◽  
Vol 353 ◽  
Author(s):  
Alexander P. Mukhamet-Galeyev ◽  
Larisa O. Magazina ◽  
Konstantin A. Levin ◽  
Nikolay D. Samotoin ◽  
Alexander V. Zotov ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Elevated Temperatures ◽  
Solid Phase ◽  
Geochemical Behavior ◽  
Slowing Down ◽  
Glass Dissolution ◽  
Detailed Composition ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Glass Leaching

At present Na-Al-P-glass is used in Russia as matrix for high level nuclear waste which include a sufficient portion of 90Sr and 137Cs isotopes. It has been known that this type of glass is characterized by relatively poor hydrothermal stability above 120°C (Krilova et al., 1990 [1], Balukova et al., 1987 [2]). Although careful studies were devoted to the glass, some questions of geochemical behavior of Sr and Cs in the limits of the nearest repository environment have remained undecided. For example, these have been left uncertain: the mechanism of the glass leaching, phenomena limiting the glass dissolution, the detailed composition of newly formed phases, temperature dependence of the glass solubility. The main purpose of the present experimental investigation was to detect factors controlling Sr and Cs concentrations of aquous solutions and to study the possibility of new solid phase formation as a factor slowing down migration of Cs and Sr in water satureted circumstance.

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.

HLW-Glass Dissolution and Co-Precipitation Studies

2006 ◽  
Vol 932 ◽  
Author(s):  
Berthold Luckscheiter ◽  
Maria Nesovic
Keyword(s):  
Fission Products ◽  
Solution Concentration ◽  
Solubility Data ◽  
Soluble Form ◽  
Glass Dissolution ◽  
Glass Corrosion ◽  
Alkaline Earths ◽  
Solid Phases ◽  
Co Precipitation

ABSTRACTTo determine the maximum attainable solution concentrations of U, Th and fission products during long-term glass corrosion, co-precipitation studies were performed. The HLW-glass GPWAK 1 was dissolved in highly acid and basic media (100 g glass/L) at 80°C and by preparing acid solutions containing the various elements in soluble form. After dissolution the pH of the solution was slowly lowered/increased and the high concentrated solutions become super-saturated and strong precipitation takes place. The found pH-dependent concentrations of the various elements reflect their different solubility, lowest concentration for Th, Zr and Fe and highest for B, alkalis and alkaline earths. To find out the solid phases controlling the solution concentration, the run of the concentrations of some elements is compared with the solubility data of their pure solid phases (e.g. hydroxides) from literature. It was found that the concentrations of Nd, Th and U in dependence on pH agree quite well with solubility data of AmOHCO3, ThO2/Th(OH)4 and Schoepite UO2·(OH)2) ·H2O. Therefore, it can be assumed that the maximum attainable concentrations of many elements are controlled by such pure solid phases.

Characterization of Lanthanoid Phases Formed Upon Glass Dissolution in Salt Solutions

1991 ◽  
Vol 257 ◽  
Author(s):  
Anette Rother ◽  
Werner Lutze ◽  
Peter Schubert-Bischoff
Keyword(s):  
Nuclear Waste ◽  
Solid Solutions ◽  
Type Material ◽  
Salt Solutions ◽  
Detailed Characterization ◽  
Glass Dissolution ◽  
Nuclear Waste Glass ◽  
Solid Phases ◽  
Additional Barrier

ABSTRACTThis communication gives a detailed characterization of some molybdate solid solutions and cerianite-type material which formed on the French borosilicate nuclear waste glass R7T7 upon corrosion in various saturated salt solutions at 110°C, 150 °C and 190 °C. The glass contained lanthanoid elements, such as neodymium, lanthanum, praseodymium, cerium and yttrium, but did not contain actinoid elements, except uranium and thorium. Various solid solutions containing lanthanoids (Ln) were found on the glass surface after corrosion, including powellite solid solutions and cerianite-type material. The secondary solid phases are characterized based on quantitative microchemical and structural analyses. These phases are expected to incorporate actinoids such as americium and curium in acid magnesiumcontaining salt solutions. The phases then constitute an additional barrier against migration of these radionuclides, which would otherwise be in the aqueous phase.

From Nanocomposite Aerogels to Glass Ceramics for Nuclear Wastes Containment

2011 ◽  
Vol 172-174 ◽  
pp. 791-796 ◽  
Author(s):  
Thierry Woignier ◽  
Jerome Reynes ◽  
Sylvie Calas
Keyword(s):  
Viscous Flow ◽  
Thermal Shock ◽  
Nuclear Waste ◽  
High Resistance ◽  
Solid Phase ◽  
Glass Ceramics ◽  
Chemical Species ◽  
Host Matrix ◽  
Waste Containment ◽  
Two Phases

Nanocomposite aerogel is proposed as a host matrix for the synthesis of glass ceramics. The large porosity is used as a sponge to incorporate chemical species getting a two phases material. We describe the steps of the synthesis of glass ceramics for nuclear waste containment, from nanocomposite aerogels loaded with actinides surrogates (Ce and Nd). The glass synthesis is obtained without melting, by a control of several solid phase transformations: sintering, viscous flow, crystallization and foaming. Thanks to their high resistance to thermal shock and water corrosion, these glass ceramics are certainly good candidates as actinides containment materials.

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.

scholarly journals Effects of Radiation Exposure on SRL 131 Composition Glass in a Steam Environment

1993 ◽  
Vol 333 ◽  
Author(s):  
D. J. Wronkiewicz ◽  
C. R. Bradley ◽  
J. K. Bates ◽  
L. M. Wang
Keyword(s):  
Radiation Exposure ◽  
Glass Surface ◽  
Average Rate ◽  
Reaction Times ◽  
Secondary Phase ◽  
Reaction Rates ◽  
Liquid Volume ◽  
Secondary Phase Formation ◽  
Effects Of Radiation ◽  
Doped Glass

ABSTRACTMonoliths of SRL 131 borosilicate glass were irradiated in a saturated air-steam environment, at temperatures of 150°C, to examine the effects of radiation on nuclear waste glass behavior. Half of the tests used actinide and Tc-99 doped glass and were exposed to an external ionizing gamma source, while the remaining glass samples were doped only with uranium and were reacted without any external radiation exposure. The effects of radiation exposure on glass alteration and secondary phase formation were determined by comparing the reaction rates and mineral paragenesis of the two sets of samples.All glass samples readily reacted with the water that condensed on their surfaces, producing two types of smectite clay within the first three days of testing. Additional crystalline phases precipitated on the altered glass surface with increasing reaction times, including zeolites, smectite, calcium and sodium silicates, phosphates, evaporitic salts, and uranyl silicates. Similar phases were produced on both the nonirradiated and irradiated samples; however, the quantity of precipitates was increased and the rate of paragenetic sequence development was accelerated in the latter. After 56 days of testing, the composite smectite layer developed at an average rate of ~0.16 and 0.63 µm/day for the nonirradiated and irradiated samples, respectively. These comparisons indicate that layer development is accelerated approximately four-fold due to the radiation exposure at high glass surface area/liquid volume (SA/V) conditions. This increase apparently occurs in response to the rapid concentration of radiolytic products, including nitric acid, in the thin films of water contacting the sample monoliths.

Solubilities and solubility products of thorium hydroxide under moderate temperature conditions

2018 ◽  
Vol 106 (8) ◽  
pp. 655-667
Author(s):  
Shogo Nishikawa ◽  
Taishi Kobayashi ◽  
Takayuki Sasaki ◽  
Ikuji Takagi
Keyword(s):  
Elevated Temperatures ◽  
Solid Phase ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Endothermic Process ◽  
Solid Phases ◽  
Solubility Products ◽  
Colloidal Species ◽  
Thorium Hydroxide

AbstractThe Th solubilities of the sample solutions that initially contained Th(OH)4(am) prepared by undersaturation and oversaturation methods in the pHcrange of 2.0–8.0 in a 0.5 M ionic strength solution of NaClO4and HClO4and stored at aging temperatures (Ta) of 298, 313 and 333 K were investigated in this study. After a certain period of time up to 40 weeks depending onTa, supernatants of the sample solutions were ultrafiltrated through 3 kDa membranes under the measurement temperature (Tm) of 298, 313 and 333 K. Size distributions of the colloidal species were investigated by ultrafiltration using membranes with different pore sizes ranging from 3 to 100 kDa, and the solid phases were examined by X-ray diffraction (XRD). The solubility of the sample solutions obtained after aging atTa=298 K using undersaturation method with continuous shaking was similar to those of dried precipitate of Th hydroxide. The solubilities obtained after aging atTa=313 and 333 K were lower than those atTa=298 K. The XRD spectra suggested that the crystallization of the solid phase proceeded under these elevated temperatures. The solubility of the sample solutions obtained after aging atTa=333 K using the oversaturation technique were similar to those prepared by undersaturation method and aged at the sameTa. A slight temperature dependence of the apparent solubilities on theTmwas observed in the sample solutions prepared by both methods. The solubility products$({K_{{\text{sp,}}{T_{\text{a}}}}}({T_{\text{m}}}))$after differentTaandTmwere determined from the solubility analysis. The observed increase in the formation constant$({K_{{\text{s,}}{T_{\text{a}}}}}({T_{\text{m}}}))$of Th4++(4+x)H2O(1)⇌Th(OH)4·xH2O(s,Ta)+4H+with increasingTmindicated that the reaction was endothermic. The enthalpy change$(\Delta_{r}H_{m\_ T_{\text{a}} \to {\text{cr}}}^{\circ} )$between the solid phases of Th(OH)4·xH2O(s,Ta) and ThO2(cr) suggested that the solid phase transformation from Th(OH)4·xH2O(s,Ta) to ThO2(cr) contains an endothermic process.

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