scholarly journals Study on Structure and Properties of La2O3-Doped Basaltic Glasses for Immobilizing Simulated Lanthanides

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4709
Author(s):  
Qin Tong ◽  
Jichuan Huo ◽  
Xingquan Zhang ◽  
Zhu Cui ◽  
Yongchang Zhu
Keyword(s):  
Thermal Stability ◽  
Chemical Stability ◽  
Glass Network ◽  
Waste Form ◽  
High Level Waste ◽  
Basaltic Glass ◽  
Consistency Test ◽  
Simulated Waste ◽  
High Level ◽  
Simulated High Level Waste

The La2O3-doped basaltic glass simulated high-level waste form (HLW) was prepared by the solid-state melt method. The simulated waste La2O3 maximum loading and the doping effect on structure, thermal stability, leaching behavior, density, and hardness of basaltic glasses were studied. XRD and SEM results show that the simulated waste loading of La2O3 in basaltic glass can be up to ~46 wt.%, and apatite (CaLa4(SiO4)3O) precipitates when the content of La2O3 reaches 56 wt.%. Raman results indicate that the addition of La2O3 breaks the Si–O–Si bond of large-membered and four-membered, but the number of A13+ involved in the formation of the network increase. Low content of La2O3 can help to repair the glass network, but it destroys the network as above 26 wt.%. DSC results show the thermal stability of simulated waste forms first increases and then decreases with the increase of La2O3 content. With the increase of La2O3 content, the density of the simulated waste form increases, and the hardness decreases. The leaching chemical stability of samples was evaluated by the ASTM Product Consistency Test (PCT) Method, which show that all the samples have good chemical stability. The leaching rates of La and Fe are three orders of magnitude lower than those of the other elements. Among them, L36 has the best comprehensive leaching performance.

Nepheline Precipitation in High-Level Waste Glasses : Compositional Effects and Impact on the Waste Form Acceptability

1996 ◽  
Vol 465 ◽  
Author(s):  
H. Li ◽  
J. D. Vienna ◽  
P. Hrma ◽  
D. E. Smith ◽  
M. J. Schweiger
Keyword(s):  
Chemical Durability ◽  
Primary Phase ◽  
Waste Form ◽  
High Level Waste ◽  
X Ray Diffraction ◽  
Consistency Test ◽  
Compositional Effects ◽  
High Level ◽  
The Impact ◽  
Glass Compositions

ABSTRACTThe impact of crystalline phase precipitation in glass during canister cooling on chemical durability of the waste form limits waste loading in glass, especially for vitrification of certain high-level waste (HLW) streams rich in Na2O and Al2O3. This study investigates compositional effects on nepheline precipitation in simulated Hanford HLW glasses during canister centerline cooling (CCC) heat treatment. It has been demonstrated that the nepheline primary phase field defined by the Na2O-Al2O3-SiO2 ternary system can be used as an indicator for screening HLW glass compositions that are prone to nepheline formation. Based on the CCC results, the component effects on increasing nepheline precipitation can be approximately ranked as Al2O3 > Na2O > Li2O ≈ K2O ≈ Fe2O3 > CaO > SiC2. The presence of nepheline in glass is usually detrimental to chemical durability. Using x-ray diffraction data in conjunction with a mass balance and a second-order mixture model for 7-day product consistency test (PCT) normalized B release, the effect of glass crystallization on glass durability can be predicted with an uncertainty less than 50% if the residual glass composition is within the range of the PCT model.

Nepheline crystallization behavior in simulated high-level waste glasses

2019 ◽  
Vol 505 ◽  
pp. 215-224 ◽  
Author(s):  
Devon L. McClane ◽  
Jake W. Amoroso ◽  
Kevin M. Fox ◽  
Albert A. Kruger
Keyword(s):  
Crystallization Behavior ◽  
High Level Waste ◽  
High Level ◽  
Simulated High Level Waste

scholarly journals Simulated high-level waste-basalt interaction experiments. Annual progress report, October 1, 1977--September 30, 1978

1978 ◽  
Author(s):  
B.E. Scheetz ◽  
D.K. Smith ◽  
M.W. Barnes ◽  
S. Komarneni ◽  
L.M. Stull ◽  
...  
Keyword(s):  
Progress Report ◽  
High Level Waste ◽  
High Level ◽  
Simulated High Level Waste ◽  
Annual Progress Report

scholarly journals Spent Fuel as a Waste Form - Data Needs to Allow Long Term Performance Assessment Under Repository Disposal Conditions.

1986 ◽  
Vol 84 ◽  
Author(s):  
V. M. Oversby
Keyword(s):  
Performance Assessment ◽  
Waste Form ◽  
High Level Waste ◽  
Detailed Knowledge ◽  
Spent Fuel ◽  
Expected Performance ◽  
High Level ◽  
Term Performance ◽  
Physical And Chemical ◽  
Waste Repositories

AbstractPerformance assessment calculations are required for high level waste repositories for a period of 10,000 years under NRC and EPA regulations. In addition, the Siting Guidelines (IOCFR960) require a comparison of sites following site characterization and prior to final site selection to be made over a 100,000 year period. In order to perform the required calculations, a detailed knowledge of the physical and chemical processes that affect waste form performance will be needed for each site. While bounding calculations might be sufficient to show compliance with the requirements of IOCFR60 and 40CFRI91, the site comparison for 100,000 years will need to be based on expected performance under site specific conditions. The only case where detailed knowledge of waste form characteristics in the repository would not be needed would be where radionuclide travel times to the accessible environment can be shown to exceed 100,000 years. This paper will review the factors that affect the release of radionuclides from spemt fuel under repository conditions, summarize our present state of knowledge, and suggest areas where more work is needed in order to support the performance assessment calculations.

Immobilization of simulated high-level waste in sintered glasses

1995 ◽  
Vol 223 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Miguel A. Audero ◽  
Arturo M. Bevilacqua ◽  
Norma B.M. de Bernasconi ◽  
Diego O. Russo ◽  
Mario E. Sterba
Keyword(s):  
High Level Waste ◽  
High Level ◽  
Simulated High Level Waste

Lessons Learned Siting and Successfully Processing U.S. DOE Radioactive Wastes Using a High Throughput Vitrification Process

2003 ◽  
Author(s):  
Robert E. Prince ◽  
Bradley W. Bowan
Keyword(s):  
The United States ◽  
Lessons Learned ◽  
Volume Reduction ◽  
Waste Form ◽  
High Level Waste ◽  
Hanford Site ◽  
High Level ◽  
Low Activity ◽  
The U.S ◽  
Ceramic Melter

This paper describes actual experience applying a technology to achieve volume reduction while producing a stable waste form for low and intermediate level liquid (L/ILW) wastes, and the L/ILW fraction produced from pre-processing of high level wastes. The chief process addressed will be vitrification. The joule-heated ceramic melter vitrification process has been used successfully on a number of waste streams produced by the U.S. Department of Energy (DOE). This paper will address lessons learned in achieving dramatic improvements in process throughput, based on actual pilot and full-scale waste processing experience. Since 1991, Duratek, Inc., and its long-term research partner, the Vitreous State Laboratory of The Catholic University of America, have worked to continuously improve joule heated ceramic melter vitrification technology in support of waste stabilization and disposition in the United States. From 1993 to 1998, under contact to the DOE, the team designed, built, and operated a joule-heated melter (the DuraMelterTM) to process liquid mixed (hazardous/low activity) waste material at the Savannah River Site (SRS) in South Carolina. This melter produced 1,000,000 kilograms of vitrified waste, achieving a volume reduction of approximately 70 percent and ultimately producing a waste form that the U.S. Environmental Protection Agency (EPA) delisted for its hazardous classification. The team built upon its SRS M Area experience to produce state-of-the-art melter technology that will be used at the DOE’s Hanford site in Richland, Washington. Since 1998, the DuraMelterTM has been the reference vitrification technology for processing both the high level waste (HLW) and low activity waste (LAW) fractions of liquid HLW waste from the U.S. DOE’s Hanford site. Process innovations have doubled the throughput and enhanced the ability to handle problem constituents in LAW. This paper provides lessons learned from the operation and testing of two facilities that provide the technology for a vitrification system that will be used in the stabilization of the low level fraction of Hanford’s high level tank wastes.

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