scholarly journals Leaching Savannah River Plant Nuclear Waste Glass in a Saturated Tuff Environment

1984 ◽  
Vol 44 ◽  
Author(s):  
N. E. Bibler ◽  
G. G. Wicks ◽  
V. M. Oversby

AbstractSamples of SRP glass containing either simulated or actual radioactive waste were leached at 90°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 to 6 months at a SA/V ratio of 100 m−1. Results with glass containing simulated waste indicated that stainless steel canister material around the glass did not significantly 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 10–100X. Also, radiolysis of the groundwater by the glass (approximately 1000 rad/hr) 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/m2, respectively, indicating that the glass-tuff system retained radionuclides well.

MRS Bulletin ◽  
1987 ◽  
Vol 12 (5) ◽  
pp. 61-65 ◽  
Author(s):  
M.J. Plodinec

At the Savannah River Plant (SRP), construction of what will be the world's largest solidification facility for nuclear waste has been under way since 1983. Beginning in 1990, the nearly 100 million liters of liquid high-level nuclear waste now stored on the site will be made into a durable borosilicate glass in this Defense Waste Processing Facility (DWPF).In developing a slurry-fed melting process for the DWPF, we made advances in understanding both glass processing and glass durability. This article focuses on what we learned and what further advances are likely to be made.Generally speaking, the goal of any glass technologist is to make a good glass and to make it well. In the glass industry a good product is whatever people will buy. To make it well means, above all, to make the product as economically as possible. Thus, the commercial glass technologist will control the composition of the melter feed material very closely to ensure that only the components necessary for glass performance are included, and in the least expensive form possible. The commercial glass technologist may also tolerate low yields or specify several stages of post-melt processing if it is necessary to produce a product to demanding specifications.To the nuclear waste glass technologist, however, a good product is one which will be stable in geologic environments for millions of years.


1984 ◽  
Vol 44 ◽  
Author(s):  
Bing-Fu Zhu ◽  
D. E. Clark ◽  
L. L. Hench ◽  
G. G. Wicks ◽  
Lars Werme

AbstractThree Savannah River Laboratory (SRL) simulated nuclear waste glasses were buried in granite boreholes 345 meters deep. Included in the same boreholes were other potential waste package components including stainless steel and bentonite. Samples were maintained at either ambient mine temperature (8–10°C) or 90°C. Differences in glass leaching performances were observed among the three compositions, with SRL 165 being more durable than SRL 131, both with 29.8% TDS waste. Likewise, the presence of some package components affected the leaching performances. Bentonite resulted in accelerated attack on the glass while the presence of stainless steel did not appear to have much effect. Results obtained through one year of burial are presented in this paper.


1991 ◽  
Vol 257 ◽  
Author(s):  
James J. Mazer ◽  
John K. Bates ◽  
Christopher M. Stevenson ◽  
C. R. Bradley

ABSTRACTMolecular water diffusion in natural obsidians and tektite was investigated in vapor hydration tests performed between 75 and 230°C for up to 400 days. Reaction progress was monitored using measurements of the birefringent hydration layer, an alteration feature associated with strain caused by molecular water diffusion in obsidians. The hydration rate constants and temperature dependence of the reaction are strongly correlated with the logarithm of the initial total water content of the glass. These values have been quantified for conditions relevant to the potential Yucca Mountain repository. The low initial total water concentrations of Savannah River Lab nuclear waste glasses produced at the bench-top scale help to minimze the effects of molecular water diffusion in waste glasses. The results of this study indicate that molecular water diffusion does not dominate waste glass reactions under conditions considered in this study. However, it is unknown whether molecular water diffusion will be important under other reaction conditions, especially longer time periods.


1981 ◽  
Vol 6 ◽  
Author(s):  
Gerald B. Woolsey ◽  
M. John Plodinec

ABSTRACTVitrification is the reference process for the immobilization of radioactive waste from the production of defense materials at the Savannah River Plant (SRP). Since 1979, a small vitrification facility (1 Ib/hr) has been operated at the Savannah River Laboratory using actual SRP waste. In previous studies. dried waste was fed to this smaller melter. This report discusses direct feeding of actual liquid-waste slurries to the small melter. These liquidfeeding tests demonstrated that addition of premelted glass frit to the waste slurry reduces the amount of material volatilized. Results of these tests are in accord with results of large-scale tests with actual waste.


1984 ◽  
Vol 44 ◽  
Author(s):  
B. A. Hamm ◽  
R. E. Eibling ◽  
M. A. Ebra ◽  
T. Motyka ◽  
H. D. Martin

AbstractAt the Savannah River Plant (SRP), a process has been developed for immobilizing high-level radioactive waste in a borosilicate glass. The waste is currently stored as soluble salts and insoluble solids. Insoluble waste as stored requires further processing before vitrification is possible. The processes required have been developed and demonstrated with actual waste. They include removal of aluminum in some waste, washing soluble salts out of the insoluble waste, and mercury stripping. Each of the processes and the results with actual SRP waste will be discussed. The benefits of each step will also be included.


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