Summary of U.S. EPA Research on Solidified/stabilized Waste Form Long-Term Durability

2009 ◽  
pp. 239-239-12 ◽  
Author(s):  
DR Kirk
Keyword(s):  
Waste Form

Study of Natural Minerals of U-Ryrochlore-Type Structure as Analogues of Plutonium Ceramic Waste-form

2002 ◽  
Vol 713 ◽  
Author(s):  
Roman V. Bogdanov ◽  
Yuri F. Batrakov ◽  
Elena V. Puchkova ◽  
Andrey S. Sergeev ◽  
Boris E. Burakov
Keyword(s):  
Chemical Shifts ◽  
Pyrochlore Structure ◽  
Type Structure ◽  
Waste Form ◽  
X Ray ◽  
Ceramic Waste ◽  
Natural Minerals ◽  
The Us ◽  
Pyrochlore Type

ABSTRACTAt present, crystalline ceramic based on titanate pyrochlore, (Ca,Gd,Hf,Pu,U)2Ti2O7, is considered as the US candidate waste form for the immobilization of weapons grade plutonium. Naturally occuring U-bearing minerals with pyrochlore-type structure: hatchettolite, betafite, and ellsworthite, were studied in orders to understand long-term radiation damage effects in Pu ceramic waste forms. Chemical shifts (δ) of U(Lδ1)– and U(Lβ1) – X-ray emission lines were measured by X-ray spectrometry. Calculations were performed on the basis of a two-dimensional δLá1- and δLδ1- correlation diagram. It was shown that 100% of uranium in hatchettolite and, probably, 95-100% of uranium in betafite are in the form of (UO2)2+. formal calculation shows that in ellsworthite only 20% of uranium is in the form of U4+ and 80% of the rest is in the forms of U5+ and U6+. The conversion of the initial U4+ ion originally occurring in the pyrochlore structure of natural minerals to (UO2)2+ due to metamict decay causes a significant increase in uranium mobility.

Aging Studies of Pu-238 and -239 Containing Calcium Phosphate Ceramic Waste-forms

2013 ◽  
Vol 1518 ◽  
pp. 73-78 ◽  
Author(s):  
Shirley K. Fong ◽  
Brian L. Metcalfe ◽  
Randall D. Scheele ◽  
Denis M. Strachan
Keyword(s):  
Calcium Phosphate ◽  
Accelerated Aging ◽  
Waste Form ◽  
Calcium Phosphate Ceramic ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Aging Studies ◽  
Flow Through ◽  
Pyrochemical Reprocessing

ABSTRACTA calcium phosphate ceramic waste-form has been developed at AWE for the immobilisation of chloride containing wastes arising from the pyrochemical reprocessing of plutonium. In order to determine the long term durability of the waste-form, aging trials have been carried out at PNNL. Ceramics were prepared using Pu-239 and -238, these were characterised by PXRD at regular intervals and Single Pass Flow Through (SPFT) tests after approximately 5 yrs.While XRD indicated some loss of crystallinity in the Pu-238 samples after exposure to 2.8 x 1018 α decays, SPFT tests indicated that accelerated aging had not had a detrimental effect on the durability of Pu-238 samples compared to Pu-239 waste-forms.

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.

Natural Analogues: Their Application to the Prediction of the Long-Term Behavior of Nuclear Waste Forms

1986 ◽  
Vol 84 ◽  
Author(s):  
Rodney C. Ewing ◽  
Michael J. Jercinovic
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Large Scale ◽  
Laboratory Data ◽  
Waste Form ◽  
Long Time ◽  
Natural Analogues ◽  
Long Term Behavior ◽  
Nuclear Waste Forms

AbstractOne of the unique and scientifically most difficult aspects of nuclear waste isolation is the extrapolation ofshot-term laboratory data (hours to years) to the long time periods (103-105 years) required by regulatory agencies for performance assessment. The direct verification of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural analogues of both the repository environment (e.g. radionuclide migration at Oklo) and nuclear waste form behavior (e.g. alteration of basaltic glasses and radiation damage in minerals) have been used to demonstrate the long-term behavior of large scale geologic systems and, on a smaller scale, waste form durability. This paper reviews the use of natural analogues to predict the long-term behavior of nuclear waste form glasses. Particular emphasis is placed on the inherent limitations of any conclusions that are based on “proof” by analogy. An example -- corrosion of borosilicate glass -- is discussed in detail with specific attention to the proper and successful use of natural analogues (basaltic glass) in understanding the long-term corrosion behavior of borosilicate glass.

Laboratory Testing of the Corrosion of Waste Glasses in Aqueous Environments - Effects of Experimental Parameters

1993 ◽  
Vol 333 ◽  
Author(s):  
AA. Barkatt ◽  
Jing C. Sang ◽  
S.-B. Xing ◽  
Yan Guo ◽  
I. L. Pegg ◽  
...  
Keyword(s):  
Test Methods ◽  
Waste Form ◽  
Test Duration ◽  
Leach Rate ◽  
Aqueous Environments ◽  
Experimental Parameters ◽  
Sensitive Function ◽  
Nuclear Waste Forms ◽  
Critical Aspects

ABSTRACTMany types of procedures have been developed for testing of the chemical durability of nuclear waste forms. These procedures differ from each other in critical aspects, such as duration, replenishment or non-replenishment of the leachates, and S/V ratio. As a result, different answers to basic questions, such as how waste-form leachability depends on its chemical composition, are obtained when different test methods are used. Furthermore, the possibility that some glasses may exhibit a leach rate excursion within the test period causes the composition dependence to be an even more sensitive function of test duration and of leachant replenishment. These factors also complicate the use of test data for the prediction of long-term waste form behavior.

Preliminary Studies of the Disposition of Cesium in a Glass-Bonded Sodalite Waste form

2002 ◽  
Vol 713 ◽  
Author(s):  
Marsha J. Lambregts ◽  
Steven M. Frank
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Fission Products ◽  
Waste Form ◽  
Resonance Spectroscopy ◽  
Ceramic Waste ◽  
Long Term Storage ◽  
Geological Repository ◽  
Term Storage

ABSTRACTArgonne National Laboratory has developed an electrometallurgical treatment for DOE spent metallic nuclear fuel. Fission products are immobilized in a durable glass bonded sodalite ceramic waste form (CWF) suitable for long term storage in a geological repository. Cesium is estimated to be in the waste form at approximately 0.1 wt.%. The exact disposition of cesium was uncertain and it was believed to be uniformly distributed throughout the waste form. A correlation of X-ray diffractometry (XRD), electron microscopy (EM), and nuclear magnetic resonance spectroscopy (NMR) performed on surrogate ceramic waste forms with high cesium loadings found a high cesium content in the glass phase and in several non-sodalite aluminosilicate phases. Cesium was not detected in the sodalite phase.

scholarly journals Cementation of Bioproducts Generated from Biodegradation of Radioactive Cellulosic-Based Waste Simulates by Mushroom

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
S. B. Eskander ◽  
S. M. Abd El-Aziz ◽  
H. El-Sayaad ◽  
H. M. Saleh
Keyword(s):  
Radioactive Waste ◽  
Portland Cement ◽  
Current Work ◽  
Waste Form ◽  
Pleurotus Pulmonarius ◽  
Long Term Stability ◽  
Surrounding Environment ◽  
Solidified Waste ◽  
Physical And Chemical

The current work was devoted to study the solidification of bioproducts originated from the bioremediation of mixture of solid cellulose-based radioactive waste simulates using a mushroom (Pleurotus pulmonarius), in Portland cement. The obtained solidified waste form was subjected to mechanical integrity qualification after curing periods of 28 and 90 days. Chemical performance of the cement-waste form was also evaluated in different leachant media during 540 days. The results obtained gave useful information about the mechanical, physical, and chemical performances of the final cement-waste form incorporated the radioactive bioproducts. Moreover, it indicated that cement can provide a highly durable form that ensures a long-term stability of the solidified waste material and can act as a first barrier against the release of radiocontaminants from radioactive wastes to the surrounding environment.

Long-Term Radioactivity Release from Solidified High-Level Waste - Part II Parametric Study of Waste form Properties, Temperature and Time

1982 ◽  
Vol 15 ◽  
Author(s):  
Friedrich K. Altenhein ◽  
Werner Lutze ◽  
Rodney C. Ewing
Keyword(s):  
Parametric Study ◽  
Computer Code ◽  
Salt Dome ◽  
Waste Form ◽  
Glass Block ◽  
High Level Waste ◽  
Surface Layers ◽  
History Of ◽  
High Level

The computer code QTERM has been used to calculate the total released activity from a single glass block when in contact with brine in a salt dome repository as a function of: (1) waste form properties, (2) leaching mechanisms, (3) retention or precipitation of specific radionuclides in surface layers, (4) thermal history of the repository and (5) decreasing activity as a function of time.

Transmission electron microscopy of alpha-decay damage and alteration of betafite

1987 ◽  
Vol 45 ◽  
pp. 376-377
Author(s):  
G. R. Lumpkin ◽  
R. C. Ewing
Keyword(s):  
Nuclear Waste ◽  
Pyrochlore Structure ◽  
Alpha Decay ◽  
Structure Type ◽  
Waste Form ◽  
Natural Analogue ◽  
The Core ◽  
Transmission Electron ◽  
Pyrochlore Group

The pyrochlore structure type occurs as a constituent of crystalline nuclear waste form assemblages proposed for the long term isolation of actinides. Betafite, the Ti-rich end-member of the pyrochlore group, is a natural analogue similar in composition to waste form pyrochlores. This study examines the effects of alpha-recoil damage and geochemical alteration on a specimen of betafite from Antanifotsy, Madagascar (Harvard no. 87876, UNM no. 205).Electron microprobe analyses were performed using a JEOL 733 Superprobe operated at 15 kV and 20 nA sample current crushed fragments of the sample were dispersed on holey-carbon grids and examined with a JEOL 2000 EX TEM operated at 200 kV. Phase compositions were checked using a Tracor TN5500 EDS.The 1.5 cm diameter betafite crystal displays an unusual zonal sequence of alteration. The core consists of relatively unaltered betafite containing ca. 27 wt.% U02 and 2.5 wt.% CaO (TABLE 1, analysis 1).

Radiation Damage in Materials – Effects of Disorder

2009 ◽  
Vol 1193 ◽  
Author(s):  
Karl R. Whittle ◽  
Mark G. Blackford ◽  
Gregory R. Lumpkin ◽  
Katherine L. Smith ◽  
Nestor J. Zaluze
Keyword(s):  
Critical Temperature ◽  
Radiation Damage ◽  
Chemical Properties ◽  
Waste Form ◽  
Physical And Chemical Properties ◽  
Long Term Stability ◽  
Effects Of Disorder ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractRadiation damage and the effect on physical and chemical properties is an important component in the prediction of the long-term stability of waste form materials. As part of the ongoing goal of increasing the accuracy of long-term predictions of radiation damage, two types of material, based on proposed materials with a waste form application have been irradiated. Results have shown that Y2TiO5 (Y2.67Ti1.33O6.67), and Yb2TiO5 (Yb2.67Ti1.33O6.67), both of which are non-stoichiometric, disordered pyrochlore-based compounds, behave significantly different to the stoichiometric, ordered pyrochlore equivalent. For example the critical temperature, the temperature above which materials remain crystalline during irradiation, is found to decrease from the ordered equivalents, e.g. Y2Ti2O7. ⁡ A second material based on La2TiO5 has been found to behave differently to both La2/3TiO3 and La2Ti2O7, with a change in Tc of ∼ 200 K.

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