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Title: Leaching fully radioactive SRP nuclear waste glass in tuff groundwater in stainless steel vessels

Abstract

SRP glass containing actual radioactive waste was leached in static tests at 90{sup 0}C in a tuffaceous groundwater (J-13 water at pH {similar_to}7.4) at a SA/V ratio of 100m{sup -1} in 316 stainless steel vessels. Tests were performed for time periods up to 134 days. Normalized mass losses were calculated for {sup 137}Cs, {sup 90}Sr, and {sup 238}Pu. The {sup 137}Cs in the leachate appeared to reach a steady value of {similar_to}3 g/m{sup 2}, corresponding to a steady-state concentration of only 1.0 ppB for total cesium. The mass losses based on {sup 90}Sr and {sup 238}Pu appearing in solution were low (<0.3 and <0.01, respectively) because of their low solubilities. However, significant amounts of these radionuclides had deposited on the steel vessel while the amount of deposited {sup 137}Cs was negligible. During the leach tests, the pH changed <0.4 unit and the only significant effect of radiolysis was reduction of NO{sub 3}{sup -} ions in solution to NO{sub 2}{sup -}. When compared to earlier tests, the results confirm that leach rates in the earlier tests with radioactive glass in Teflon vessels were high due to radiolysis of the Teflon. The results also indicate that radioactive and nonradioactive glasses of comparablemore » composition and surface finish leach essentially identically. 12 refs., 3 figs., 4 tabs.« less

Authors:
Publication Date:
Research Org.:
Savannah River Lab., Aiken, SC (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
60619
Report Number(s):
DP-MS-85-141; CONF-860418-18
ON: DE86015703
DOE Contract Number:
AC09-76SR00001
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1986
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 05 NUCLEAR FUELS; BOROSILICATE GLASS; LEACHING; GROUND WATER; TUFF; TEMPERATURE RANGE 0273-0400 K; STAINLESS STEEL-316; CESIUM 137; STRONTIUM 90; PLUTONIUM 238; EXPERIMENTAL DATA; Yucca Mountain Project

Citation Formats

Bibler, N.E.. Leaching fully radioactive SRP nuclear waste glass in tuff groundwater in stainless steel vessels. United States: N. p., 1986. Web. doi:10.2172/60619.
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Bibler, N.E.. Leaching fully radioactive SRP nuclear waste glass in tuff groundwater in stainless steel vessels. United States. doi:10.2172/60619.
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Bibler, N.E.. Wed . "Leaching fully radioactive SRP nuclear waste glass in tuff groundwater in stainless steel vessels". United States. doi:10.2172/60619. https://www.osti.gov/servlets/purl/60619.
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@article{osti_60619,
title = {Leaching fully radioactive SRP nuclear waste glass in tuff groundwater in stainless steel vessels},
author = {Bibler, N.E.},
abstractNote = {SRP glass containing actual radioactive waste was leached in static tests at 90{sup 0}C in a tuffaceous groundwater (J-13 water at pH {similar_to}7.4) at a SA/V ratio of 100m{sup -1} in 316 stainless steel vessels. Tests were performed for time periods up to 134 days. Normalized mass losses were calculated for {sup 137}Cs, {sup 90}Sr, and {sup 238}Pu. The {sup 137}Cs in the leachate appeared to reach a steady value of {similar_to}3 g/m{sup 2}, corresponding to a steady-state concentration of only 1.0 ppB for total cesium. The mass losses based on {sup 90}Sr and {sup 238}Pu appearing in solution were low (<0.3 and <0.01, respectively) because of their low solubilities. However, significant amounts of these radionuclides had deposited on the steel vessel while the amount of deposited {sup 137}Cs was negligible. During the leach tests, the pH changed <0.4 unit and the only significant effect of radiolysis was reduction of NO{sub 3}{sup -} ions in solution to NO{sub 2}{sup -}. When compared to earlier tests, the results confirm that leach rates in the earlier tests with radioactive glass in Teflon vessels were high due to radiolysis of the Teflon. The results also indicate that radioactive and nonradioactive glasses of comparable composition and surface finish leach essentially identically. 12 refs., 3 figs., 4 tabs.},
doi = {10.2172/60619},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1986},
month = {Wed Jan 01 00:00:00 EST 1986}
}
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DOI:  10.2172/60619
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  • SRP glass containing actual radioactive waste was leached in static tests at 90{sup 0}C in a tuffaceous ground water at an SA/V ratio of 100 m/sup -1/ in 316 stainless steel vessels. Tests were performed for up to 134 days. Normalized mass losses were calculated for /sup 137/Cs, /sup 90/Sr, and /sup 238/Pu. The /sup 137/Cs in the leachate appeared to reach a steady value of {approx}3 g/m/sup 2/, corresponding to steady state concentration of only 1.0 ppb for total cesium. The mass losses based on /sup 90/Sr and /sup 238/Pu appearing in solution were low (<0.3 and <0.01, respectively),more » because of their low solubilities. However, significant amounts of these radionuclides had deposited on the steel vessel, while the amount of deposited /sup 137/Cs was negligible. During the leach tests, the pH changed <0.4 units and the only significant effect of radiolysis was reduction of NO/sub 3//sup -/ ions in solution to NO/sub 2//sup -/. When compared to earlier tests, the results confirm that leach rates in the earlier tests with radioactive glass in Teflon vessels were high due to radiolysis of the Teflon. The results also indicate that radioactive and nonradioactive glasses of comparable composition and surface finish leach essentially identically.« less

  • ; ; ; ... - Mater. Res. Soc. Symp. Proc.; (United States)
    The results from the JSS phase II static glass leaching experiments are presented. The experiments have been performed in the presence of bentonite, granite and stainless steel corrosion products at 90/sup 0/C for 28 days. The leaching behavior of Cs has been analyzed using gamma-spectrometry. The surface of the leached glass samples has been analyzed by infrared reflection spectrometry. The presence of uncompacted bentonite seems to have a very small, increasing, effect on the leach rate of the glass compared to when no bentonite is present. In the presence of compacted bentonite, a lower leach rate has been found thanmore » in the presence of uncompacted bentonite. (For Cs 0.3 g x m/sup -2/ x d/sup -1/ and 0.7 g x m/sup -2/ x d/sup -1/ respectively.) The addition of stainless steel corrosion products seems to have a slightly increasing effect on the leach rate in the presence of compacted bentonite. The beneficial effect of granite on the leach rate seems to be overshadowed by the presence of uncompacted bentonite.« less

  • ; ;
    Samples of SRP glass containing either simulated or actual radioactive waste were leached at 90{sup 0}C under conditions simulating a saturated tuff repository environment. The leach vessels were fabricated of tuff and actual tuff groundwater was used. Thus, the glass was leached only in the presence of those materials (including the Type 304L stainless steel canister material) that would be in the actual repository. Tests were performed for time periods up t 6 months at a SA/V ratio of 100 m{sup -1}. Results with glass containing simulated waste indicated that stainless steel canister material around the glass did not significantlymore » affect the leaching. Based on Li and B (elements not in significant concentrations in the tuff or tuff groundwater), glass containing simulated waste leached identically to glass containing actual radioactive waste. The tuff buffered the pH so that only a slight increase was observed as a result of leaching. Results with glass containing actual radioactive waste indicated that tuff reduced the concentrations of Cs-137, Sr-90, and Pu-238 in the free groundwater in the simulated repository by 10 to 100X. Also, radiolysis of the groundwater by the glass (approximately 1000 rad/h) did not significantly affect the pH in the presence of tuff. Measured normalized mass losses in the presence of tuff for the glass based on Cs-137, Sr-90, and Pu-238 in the free groundwater were extremely low, nominally 0.02, 0.02, and 0.005 g/m{sup 2}, respectively, indicating that the glass-tuff system retained radionuclides well. 9 references, 2 figures, 3 tables.« less

  • ; ;
    A laboratory leaching test has been performed as part of a project to evaluate the suitability of tuff rocks at Yucca Mountain, Nevada, as a site for a high-level nuclear waste repository. Glass samples were placed in water inside tuff vessels, and then the tuff vessels were placed in water inside Teflon containers. Glass-component leach rates and migration through the tuff were measured for samples of the ATM-8 actinide glass, which is a PNL 76-68 based glass doped with low levels of {sup 99}Tc, {sup 237}Np, {sup 238}U, and {sup 239}Pu to simulate wastes. Disc samples of this glass weremore » leached at 90{sup 0}C for 30, 90, and 183 days inside tuff vessels using a natural groundwater (J-13 well-water) as the leachant. At the end of each leaching interval, the J-13 water present inside and outside the rock vessel was analyzed for glass components in solutions. Boron, molybdenum, and technetium appear to migrate through the rock at rates that depend on the porosity of each vessel and the time. The actinide elements were found only in the inner leachate. Normalized elemental mass loss values for boron, molybdenum, and technetium were calculated using concentrations of the inner and outer leachates and assuming a negligible retention on the rock. The maximum normalized release was 2.3 g/m{sup 2} for technetium. Boron, molybdenum, technetium, and neptunium were released linearly with respect to each other, with boron and molybdenum released at about 85% of the technetium rate, and neptunium at 5 to 10% of the technetium rate. Plutonium was found at low levels in the inner leachate but was strongly sorbed on the steel and Teflon supports. Neptunium was sorbed to a lesser extent. 8 refs., 6 figs., 6 tabs.« less

  • As part of continuing Department of Energy (DOE)-sponsored studies in waste management, the Pacific Northwest Laboratory (PNL) has been conducting the High-Level Waste Immobilization Program. The purpose of this program is to develop and demonstrate technology for incorporating nuclear wastes into final waste forms. The preparation and leach testing of fully radioactive, zinc borosilicate glass, which was prepared from power reactor waste, are described. Leach testing using the International Atomic Energy Association (IAEA) procedure was performed in deionized water for a period of 1.75 years. Leach rates were determined for activation products, fission products, and actinides. These rates ranged frommore » 4 x 10/sup -5/ g of glass/cm/sup 2/-day, based on cesium, to 4 x 10/sup -9/ g of glass/cm/sup 2/-day, based on cerium. Following is the ranking of the release rates of the elements, from highest to lowest: Cs > Sr > Co > Sb > Mn > Pu > Eu > Rh > Cm > Ce. A similar leach test, using the same glass composition but with nonradioactive elements, has recently been completed. The leach rates of Cs and Sr for the nonradioactive glass were found to be in close agreement with those in this study. Slopes calculated from curves of cumulative fractions leached show that radioisotope release begins with a diffusion-type mechanism and changes gradually to a silicate lattice alteration mechanism. Changes in sampling frequency altered the apparent release mechanism when leachant changes were longer than one month. The leach rates were quite constant for samples taken from the top to the bottom of the glass melt, indicating a homogeneous product. Safety assessment studies and modeling programs use leach rates to predict the amount of radioactive material released should the waste be contacted by aqueous solutions. Further tests, focusing on geologic storage conditions and using fully radioactive wastes, are planned.« less