Physical Properties of Saltstone: Physical Properties of Saltstone: A Savannah River Plant Waste Form

1984 ◽  
Vol 44 ◽  
Author(s):  
Christine A. Langton
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Field Tests ◽  
Waste Form ◽  
Savannah River ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Leach Rate ◽  
Savannah River Plant ◽  
Water To Cement Ratio

AbstractA cement-based waste form, “saltstone,” has been designed for disposal of Savannah River Plant low-level radioactive salt waste. Laboratory and field tests indicate that this stabilization process greatly reduces the mobility of all of the waste constituents in the surface and near-surface environment. Bulk properties of this material have been tailored with respect to salt leach rate, permeability, and compressive strength. Microstructure and mineralogy were characterized by SEM and x-ray diffraction analyses.Compressive strength was found to increase as the water to cement ratio decreased. Porosity and mean pore size increased with increasing water to cement ratios. Bulk diffusivities of the various ions dissolved in the pore solutions were also found to increase as water to cement ratios increased.

scholarly journals Cement-Based Waste forms for Disposal of Savannah River Plant Low-Level Radioactive Salt Waste

1983 ◽  
Vol 26 ◽  
Author(s):  
Christine A. Langton ◽  
Michael D. Dukes ◽  
Randolph V. Simmons
Keyword(s):  
Disposal Site ◽  
Savannah River ◽  
Soluble Salts ◽  
X Ray Diffraction ◽  
Bulk Properties ◽  
X Ray ◽  
Low Level ◽  
Leach Rate ◽  
Savannah River Plant ◽  
Salt Waste

ABSTRACTDefense waste processing at the Savannah River Plant will include decontamination and disposal of approximately 100 million liters of soluble salts containing primarily NaNO3, NaOH, NaNO2, NaAl(OH)4, and Na2SO4. A cement-based waste form, “saltstone,” has been designed for disposal of Savannah River Plant low-level radioactive salt waste. Bulk properties of this material have been tailored with respect to salt leach rate, permeability, and compressive strength. Microstructure and mineralogy of leached and unleached specimens were characterized by SEM and X-ray diffraction analyses, respectively. It has been concluded that the salt leach rate can be limited so that amounts of salt and radionuclides in the groundwater at the perimeter of the 100 acre disposal site will not exceed EPA drinking water standards.

Effects of Alpha, Gamma, and Alpha-Recoil Radiation on Borosilicate Glass Containing Savannah River Plant Defense High-Level Nuclear Waste

1981 ◽  
Vol 6 ◽  
Author(s):  
Ned E. Bibler
Keyword(s):  
Borosilicate Glass ◽  
Deionized Water ◽  
Savannah River ◽  
Γ Radiation ◽  
Leach Rate ◽  
Geologic Storage ◽  
Savannah River Plant ◽  
Pb Ions ◽  
High Level ◽  
Doped Glass

ABSTRACTAt the Savannah River Plant, the reference process for the immobilization of defense high-level waste (DHLW) for geologic storage is vitrification into borosilicate glass. During geologic storage for 106y, the glass would be exposed to ∼3 × 1010 rad of β radiation, ∼1010 rad of γ radiation, and 1018 particles/g glass for both α and α-recoil radiation. This paper discusses tests of the effect of these radiations on the leachability and density of the glass. No effect of the radiations was detected that reduced the effectiveness of the glass for long-term storage of DHLW even at doses corresponding to 106 years storage for the actual glass. For the tests, glass containing simulated DHLW was prepared from frit of the reference composition. Three methods were used to irradiate the glass: external irradiations with beams of ∼200 keV or Pb ions, internal irradiations with Cm–244 doped glass, and external irradiations with Co–60 γ rays. Results with both Xe and Pb ions indicate that a dose of 3 × 1013 ions/cm2 (simulating >106 years storage) does not significantly increase the leachability of the glass in deionized water. Tests with Cm–244 doped glass show no increase in leach rate in deionized water up to a dose of 1.3 × 1018 α and α-recoils/g glass. The density of the Cm–244 doped glass has decreased by 1% at a dose of 1018 particles/g glass. With γ-radiation, the density has changed by <0.05% at a dose of 8.5 × 1010 rad. Results of leach tests in deionized water and brine indicated that this very large dose of γ-radiation increased the leach rate by only 20%. Also, the leach rates are 3 to 4 times lower in brine.

scholarly journals Nuclear waste-form risk assessment for US Defense waste at Savannah River Plant. Annual report FY 1981

1981 ◽  
Author(s):  
H. Cheung ◽  
L.L. Edwards ◽  
T.F. Harvey ◽  
D.D. Jackson ◽  
M.A. Revelli
Keyword(s):  
Risk Assessment ◽  
Nuclear Waste ◽  
Annual Report ◽  
Waste Form ◽  
Savannah River ◽  
Savannah River Plant

Effect of Firing Temperature on Mechanical and Physical Properties of Porcelain Balls as Grinding Media

2017 ◽  
Vol 888 ◽  
pp. 37-41
Author(s):  
Hasrul Yahya ◽  
Mohd Roslee Othman ◽  
Zainal Arifin Ahmad
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Water Absorption ◽  
Firing Temperature ◽  
Chemical Resistance ◽  
Firing Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grinding Media ◽  
Mechanical And Physical Properties

Porcelain balls as grinding media are produced by firing process of clay, quartz and feldspar mixtures. This application need high technological properties such as high compressive strength and hardness, wear resistance, low water absorption and excellent chemical resistance. These properties are associated with higher firing temperatures. The porcelain balls were prepared by mixing 30 wt.% clay, 40 wt.% feldspar and 30 wt.% quartz. The samples were sintered at 1200°C, 1230°C, 1250°C, 1270°C and 1300°C for 2 hours with heating rate of 3°C/min. Both green powder and fired samples were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM).The properties of the fired samples were evaluated by compressive strength, hardness, shrinkage, water absorption, bulk density, and porosity measurement. Increasing of compressive strength, hardness and density are associated with increasing of firing temperatures. Porcelain balls PB1 and PB2 can be produced as grinding media with optimum mechanical and physical properties at firing temperature 1270°C and 1250°C, respectively.

scholarly journals Results from the Long-Term Interaction and Modeling of SRL-131 Glass with Aqueous Solutions

1985 ◽  
Vol 50 ◽  
Author(s):  
Denis M. Strachan ◽  
L. R. Pederson ◽  
R. O. Lokken
Keyword(s):  
South Carolina ◽  
Cementitious Materials ◽  
Insoluble Fraction ◽  
Performance Criteria ◽  
National Defense ◽  
Savannah River ◽  
Geologic Repository ◽  
Glass Waste ◽  
Near Surface ◽  
Savannah River Plant

During the various processing activities in the production of plutonium for the U.S. national defense programs, waste by-products were generated. These wastes, which have been generated over about the past 40 years at sites such as Savannah River Plant in South Carolina and Hanford in Washington, have been stored in underground tanks. Plans for the final disposal of the Savannah River Plan waste have now been documented [1] and call for the decontaminated soluble fraction of the waste to be mixed with cementitious materials and disposed of in near-surface trenches [2]. The radionuclide fraction of the soluble waste and the insoluble fraction of the waste will be converted to glass and sent to a geologic repository. In order for the repository to accept the glass, certain performance criteria must be met. Although not fully defined, it is certain that these criteria will include some specification on the rate of release of nuclides from the glass waste form when contacted by water.

Thermal Properties of Fly Ash-Slag Cement Waste forms for Disposal of Savannah River Plant Salt Waste

1985 ◽  
Vol 65 ◽  
Author(s):  
S. Kaushal ◽  
D. M. Roy ◽  
P. H. Licastro ◽  
C. A. Langton
Keyword(s):  
Thermal Properties ◽  
Fly Ash ◽  
Thermal Stresses ◽  
Waste Form ◽  
Savannah River ◽  
Granulated Blast Furnace Slag ◽  
Savannah River Plant ◽  
High Calcium ◽  
Mechanical Durability ◽  
Concentrated Solution

ABSTRACTWaste processing at the Savannah River Plant will involve reconstitution of the salts (NaNO3, NaNO2, Na2 SO4 and NaOH) into a concentrated solution followed by solidification in a cement-based waste form. Phase stability and mechanical durability of this material will depend to a considerable extent on the thermal properties of the waste form. Fly ash has been used to moderate the hydration and setting processes so as to avoid high temperatures which could cause thermal stresses. Both high-calcium (Class C) and low-calcium (Class F) fly ashes were studied. Other constituents of the mixes include granulated blast furnace slag and finely crushed lime-stone. The adiabatic temperature increases and thermal conductivities were measured and related to matrix mineralogy and microstructure as determined by x-ray diffraction and scanning electron microscopy, respectively.

scholarly journals Near-Surface Leaching Studies of Pb-Implanted Savannah River Waste Glass

1981 ◽  
Vol 11 ◽  
Author(s):  
G. W. Arnold ◽  
C. J. M. Northrup ◽  
N. E. Bibler
Keyword(s):  
Energy Deposition ◽  
Surface Damage ◽  
High Level Waste ◽  
Savannah River ◽  
Near Surface ◽  
Ion Tracks ◽  
Savannah River Plant ◽  
High Level ◽  
Storage Times ◽  
Long Storage

Ion implantation into simulated nuclear waste glasses is a rapid means of producing near-surface energy deposition similar to that produced by α-recoil nuclei after long storage times (typically 103 – 106 years). For example, Dran, Maurette, and Petit1 used 200 keV Pb-ion implantations in glass at a fluence of 5 × 1012/cm2 to produce surface damage. This fluence is equivalent to approximately 2 × 1018 alpha-decays/cm3 which corresponds to approximately 106 years storage for glass containing Savannah River Plant (SRP) defense high-level waste (DHLW). These authors1 found that this fluence value corresponded to a critical fluence (Φc) for enhanced etching (a factor of 20 increase as inferred by step-height changes) for several silicate glasses when etched in a NaCl solution at 100°C. This critical fluence value also corresponds very well with the fluence at which significant overlap of individual ion tracks occurs.

scholarly journals Physical properties and hydration evolution of dispersant containing calcium aluminate cement compositions for endodontic applications

Cerâmica ◽  
2014 ◽  
Vol 60 (355) ◽  
pp. 366-370 ◽  
Author(s):  
A. P. Luz ◽  
V. C. Pandolfelli
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Calcium Aluminate ◽  
Dimensional Change ◽  
Calcium Aluminate Cement ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray ◽  
Polymeric Dispersant ◽  
Aluminate Cement

The purpose of this study was to evaluate the physical properties and hydration evolution of calcium aluminate cement (CAC) compositions containing an advanced dispersant. The compressive strength, dimensional change, apparent porosity and quantitative X ray diffraction analysis (XRD) of the cement pastes were carried out over 1-15 days of curing (with the samples immersed in distilled water) at 37 ºC. The addition of a polymeric dispersant to the selected CAC (Secar 71) resulted in higher, but suitable expansion of the cement samples, and improved uniaxial compressive strength reaching values in the range of 73-87 MPa after 15 days. Quantitative XRD results also showed that C3AH6 and Al(OH)3 were the main phases detected during the cement hydration process, but CAH10 and C2AH8 were also found due to the higher water availability in the curing environment. According to the attained results, it could be concluded that the dispersant containing calcium aluminate cement compositions have the potential to be used as endodontic materials.

Slag-Based Saltstone Formulations

1987 ◽  
Vol 112 ◽  
Author(s):  
C. A. Langton
Keyword(s):  
Fly Ash ◽  
Heat Of Hydration ◽  
Waste Form ◽  
Savannah River ◽  
Ion Release ◽  
Alkaline Salt ◽  
Savannah River Plant ◽  
Physical Entrapment ◽  
Class F Fly Ash ◽  
Class F

AbstractApproximately 400 × 106 liters of low-level alkaline salt solution will be treated at the Savannah River Plant (SRP) Defense Waste Processing Facility (DWPF) prior to disposal in concrete vaults at SRP. Treatment involves removal of Ca+and Sr+2 followed by solidification and stabilization of potential contaminants in saltstone, a hydrated ceramic waste form.Chromium, technetium, and nitrate releases from saltstone can be significantly reduced by substituting hydraulic blast furnace slag for portland cement in the formulation designs. Slag-based mixes are also compatible with Class F fly ash used in saltstone as a functional extender to control heat of hydration and reduce permeability. (Class F fly ash is locally available at SRP.)A monolithic waste form is produced by the hydration of the slag and fly ash. Soluble ion release (NO3−) is controlled by the saltstone microstructure (bulk porosity and pore size and connectivity). Chromium and technetium are 103−104 times less leachable from slag mixes than from cement-based waste forms. Results suggest that chemical stabilization rather than physical entrapment, as in the case of nitrate is responsible for this improved leaching. Reduction of Cr+6 and Tc+7 to Cr+3 and Tc+4 by ferrous iron or Mn+2 in the slag and subsequent precipitation of the relatively insoluble phses Cr(OH)3 and TcO2 are proposed as the stabilizing reactions.

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