Weathered Basalt Glass: A Natural Analogue for the Effects of REACTION Progress on Nuclear Waste Glass Alteration

1985 ◽  
Vol 50 ◽  
Author(s):  
B. Grambow ◽  
M. J. Jercinovic ◽  
R. C. Ewing ◽  
C. D. Byers
Keyword(s):  
Nuclear Waste ◽  
Laboratory Experiments ◽  
Reaction Rates ◽  
Similar Reaction ◽  
Natural Analogue ◽  
Reaction Progress ◽  
Basalt Glass ◽  
Basalt Glasses ◽  
Analogous Behavior

AbstractLaboratory experiments alone cannot be used to verify models for the long-term release of radionuclides from nuclear waste glasses. Basalt glasses have been proposed as an appropriate natural analogue for the long-term validation of release models [1]. Their analogous behavior has been demonstrated in laboratory experiments in which both types of glasses display similar reaction rates, alteration products and surface layer morphologies [2,3]. This paper illustrates how empirical data from natural occurrences of basalt glass can be interpreted by a model which is developed to describe the reaction progress of the corrosion of nuclear waste form borosilicate glass [4,5].

scholarly journals Basalt Glass: An Analogue for the Evaluation of the Long-Term Stability of Nuclear Waste form Borosilicate Glasses

1984 ◽  
Vol 44 ◽  
Author(s):  
C. D. Byers ◽  
M. J. Jercinovic ◽  
R. C. Ewing ◽  
K. Keil
Keyword(s):  
Nuclear Waste ◽  
Laboratory Data ◽  
Waste Form ◽  
Borosilicate Glasses ◽  
Term Stability ◽  
Long Term Stability ◽  
Basalt Glass ◽  
Time Periods ◽  
Basalt Glasses

AbstractThe long-term stability of nuclear waste form borosilicate glasses can be evaluated by understanding the processes that effect the long-term alteration of glass and by comparing laboratory alteration of synthetic basalt and borosilicate glasses with the observed stability of naturally occurring basaltic glasses in diverse geologic environments. This paper presents detailed electron microprobe analyses of naturally altered basaltic glasses (with maximum ages of 10,000 to 20 million years) from low-temperature environments. These results are compared to laboratory data on the corrosion of a synthetic basaltic glass in MCC-1 tests (90°C, a SA/V of 0.1 cm−1 and time periods up to 182 days), MCC-2 tests (190°C, a SA/V of 0.1 cm−1 and time periods up to 210 days) and hydration tests in saturated water vapor (240°C, an estimated SA/V of ∼ 106 cm−1 and time periods up to 63 days). Additionally, laboratory induced hydration alteration of synthetic basalt and borosilicate glasses is compared. These preliminary experiments provide evidence that the alteration processes observed for natural basalt glasses are relevant to understanding the alteration of nuclear waste glass, as both appear to react via similar processes.

Studies of Ancient Glass and Their Application to Nuclear-Waste Management

MRS Bulletin ◽  
2003 ◽  
Vol 28 (7) ◽  
pp. 500-504 ◽  
Author(s):  
Hannelore Römich
Keyword(s):  
Waste Management ◽  
Nuclear Waste ◽  
Laboratory Experiments ◽  
Glass Composition ◽  
Nuclear Waste Management ◽  
High Potassium ◽  
Ancient Glass ◽  
Long Term Behavior ◽  
High Potassium Content

AbstractDuring several hundred years of burial in the soil, glass objects, especially those with the high potassium content of medieval compositions, develop heavily corroded surfaces, showing phenomena such as local pitting, laminated layers, and browning effects. The long-term behavior of glass in the soil or in contact with groundwater is not only of interest to glass scientists with a background in archaeology, but also for those with a special interest in nuclear-waste management. Several attempts have been made to propose the decomposition of ancient glasses as an indicator for the performance of buried nuclear-waste glasses. In spite of differences in glass composition and exposure conditions, the development of alteration or corrosion layers with time is a common concern, as shown in this article. Laboratory experiments, representing a simplified model for real conditions, offer the possibility for systematic investigations.

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).

Alteration of basalt glasses: implications for modelling the long-term stability of nuclear waste glasses

Nature ◽  
1985 ◽  
Vol 314 (6008) ◽  
pp. 252-255 ◽  
Author(s):  
W. Lutze ◽  
G. Malow ◽  
R. C. Ewing ◽  
M. J. Jercinovic ◽  
K. Keil
Keyword(s):  
Nuclear Waste ◽  
Term Stability ◽  
Long Term Stability ◽  
Basalt Glasses

Dissolution of Basaltic Glass in Seawater : Experiments and Thermodynamic Modelling

1985 ◽  
Vol 50 ◽  
Author(s):  
J. L. Crovisier ◽  
B. Fritz ◽  
B. Grambow ◽  
J. P. Eberhart
Keyword(s):  
Nuclear Waste ◽  
Natural Waters ◽  
Thermodynamic Modelling ◽  
Basaltic Glass ◽  
Analog Systems ◽  
Basalt Glasses

The reaction of basalt glasses with natural waters were proposed as analog systems to the long-term alteration of nuclear waste glasses in the geosphere [1].

scholarly journals Solubility Product of Vanadinite Pb5(VO4)3Cl at 25 °C—A Comprehensive Approach to Incongruent Dissolution Modeling

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 135
Author(s):  
Justyna Topolska ◽  
Bartosz Puzio ◽  
Olaf Borkiewicz ◽  
Julia Sordyl ◽  
Maciej Manecki
Keyword(s):  
Nuclear Waste ◽  
Solubility Product ◽  
Geochemical Modeling ◽  
Incongruent Dissolution ◽  
Mineral Solubility ◽  
Actual Application ◽  
Universal Approach ◽  
Solubility Constant ◽  
First Time

Although vanadinite (Pb5(VO4)3Cl) occurs in abundance in various terrestrial geochemical systems of natural and anthropogenic origin and is seriously considered as a potential nuclear waste sequestering agent, its actual application is severely limited by a lack of understanding of its basic thermodynamic parameters. In this regard, the greatest challenge is posed by its incongruent dissolution, which is a pivotal hurdle for effective geochemical modeling. Our paper presents an universal approach for geochemical computing of systems undergoing incongruent dissolution which, along with unique, long-term experiments on vanadinites’ stability, allowed us to determine the mineral solubility constant. The dissolution experiments were carried out at pH = 3.5 for 12 years. Vanadinite has dissolved incongruently, continuously re-precipitating into chervetite (Pb2V2O7) with the two minerals remaining in mutual equilibrium until termination of the experiments. The empirically derived solubility constant Ksp,V,298 = 10–91.89 ± 0.05 of vanadinite was determined for the first time. The proposed modeling method is versatile and can be adopted to other mineral systems undergoing incongruent dissolution.

Geochemical Behaviour of Uranium in Sedimentary Formations: Insights From a Natural Analogue Study

2009 ◽  
Author(s):  
Ulrich Noseck ◽  
Vaclava Havlova ◽  
Juhani Suksi ◽  
Thomas Brasser ◽  
Radek Cervinka
Keyword(s):  
Current Knowledge ◽  
Natural Analogue ◽  
Near Surface ◽  
Co2 Partial Pressure ◽  
Long Term Stability ◽  
Reducing Conditions ◽  
Phosphate Mineral ◽  
Sedimentary System ◽  
The Impact

Groundwater data from the natural analogue site Ruprechtov have been evaluated with special emphasis on the uranium behaviour in the so-called uranium-rich clay/lignite horizon. In this horizon in-situ Eh-values in the range of −160 to −280 mV seem to be determined by the SO42−/HS− couple. Under these conditions U(IV) is expected to be the preferential redox state in solution. However, on-site measurements in groundwater from the clay/lignite horizon show only a fraction of about 20% occurring in the reduced state U(IV). Thermodynamic calculations reveal that the high CO2 partial pressure in the clay/lignite horizon can stabilise hexavalent uranium, which explains the occurrence of U(VI). The calculations also indicate that the low uranium concentrations in the range between 0.2 and 2.1μg/l are controlled by amorphous UO2 and/or the U(IV) phosphate mineral ningyoite. This confirms the findings from previous work that the uranium (IV) mineral phases are long-term stable under the reducing conditions in the clay/lignite horizon without any signatures for uranium mobilisation. It supports the current knowledge of the geological development of the site and is also another important indication for the long-term stability of the sedimentary system itself, namely of the reducing geochemical conditions in the near-surface (30m to 60 m deep) clay/lignite horizon. Further work with respect to the impact of changes in redox conditions on the uranium speciation is on the way.

scholarly journals THE TRANSMUTATION MODELING FOR PLUTONIUM AND MINOR ACTINIDES IN THE TWO-ZONE SUBCRITICAL REACTOR

2019 ◽  
pp. 83-87
Author(s):  
V.I. Gulik ◽  
D.O. Sheliahovskyi ◽  
A.V. Nosovskyi
Keyword(s):  
Nuclear Waste ◽  
Reaction Rates ◽  
Fast Neutrons ◽  
Minor Actinides ◽  
Capture Reaction ◽  
Thermal And Fast Neutrons ◽  
Subcritical System ◽  
Subcritical Reactor

The investigations directed to plutonium and minor actinides transmutations for two-zone subcritical reactor is considered in present paper. The distributions of thermal and fast neutrons in the subcritical system were obtained. The distributions of fission and capture reaction rates for 237Np and 243Am were analyzed from viewpoint of minor actinides transmutation. The transmutation simulations for different distributions of pin targets were carried out within the scope of this paper. The obtained modeling results for different nuclear waste isotopes were analyzed and discussed.

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