The Release of Technetium from Defense Waste Processing Facility Glasses

MRS Proceedings ◽

10.1557/proc-412-221 ◽

1995 ◽

Vol 412 ◽

Cited By ~ 6

Author(s):

W. L. Ebert ◽

S. F. Wolf ◽

J. K. Bates

Keyword(s):

Glass Surface ◽

Laboratory Tests ◽

Water Solution ◽

Waste Processing ◽

Glass Dissolution ◽

Test Conditions ◽

Processing Facility ◽

Nitrite Nitrate ◽

Solution Volume

AbstractLaboratory tests are being conducted using two radionuclide-doped Defense Waste Processing Facility (DWPF) glasses (referred to as SRL 131A and SRL 202A) to characterize the effects of the glass surface area/solution volume (SN) ratio on the release and disposition of Tc and several actinide elements. Tests are being conducted at 90°C in a tuff ground water solution at S/V ratios of 10, 2000, and 20,000 m−1 and have been completed through 1822 days. The formation of certain alteration phases in tests at 2000 and 20,000 m−1 results in an increase in the dissolution rates of both glasses. The release of Tc parallels that of B and Na under most test conditions and its release increases when alteration phases form. However, in tests with SRL 202A glass at 20,000 m−1, the Tc concentration in solution decreases coincidentally with an increase in the nitrite/nitrate ratio that indicates a decrease in the solution Eh. This may have occurred due to radiolysis, glass dissolution, the formation of alteration phases, or vessel interactions. Technetium that was reduced from Tc(VII) to Tc(IV) may have precipitated, though the amount of Tc was too low to detect any Tc-bearing phases. These results show the importance of conducting long-term tests with radioactive glasses to characterize the behavior of radionuclides, rather than relying on the observed behavior of nonradioactive surrogates.

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The Long-Term Dissolution Behaviour of the Pamela Borosilicate Glass SM527 - Application of SA/V as Accelerating Parameter

MRS Proceedings ◽

10.1557/proc-257-49 ◽

1991 ◽

Vol 257 ◽

Cited By ~ 8

Author(s):

K. Lemmens ◽

P. Van Iseghem

Keyword(s):

Borosilicate Glass ◽

Water Mixture ◽

Boom Clay ◽

Glass Dissolution ◽

Dissolution Behaviour ◽

Powdered Glass ◽

Clay Slurry ◽

Term Data ◽

Solution Volume

ABSTRACTThe Al2O3 rich borosilicate glass SM527 was submitted to corrosion tests with glass surface area to solution volume ratios ranging from 10 to 10000 m-1. This latter condition would correspond with a 1000 fold acceleration relative to the reference MCCI condition. Powdered glass was used to reach SANV ratios of 500 m-1 and more. The leaching solutions were either distilled water or referred to Boom clay disposal conditions. The results based on the boron concentration in solution revealed a relatively linear dependence on SA/V.t0.5 in the pure solutions, on the longer term (DW and clay water). Diffusion is suggested to be the process governing the glass dissolution, although other processes should not be excluded. In a clay / clay water mixture (slurry), long term dissolution seems to be limited by saturation. Short term data for boron are largest in the clay slurry, but with time the boron concentrations converge to similar values in the three media considered. The use of SA/V as an accelerating factor is promising, but certainly requires additional research.

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Effects of glass surface area-to-solution volume ratio (S/V) on glass dissolution. Part one: Relationship between S/V and leachate pH

10.2172/10194453 ◽

1992 ◽

Author(s):

X. Feng ◽

I.L. Pegg

Keyword(s):

Surface Area ◽

Glass Surface ◽

Volume Ratio ◽

Glass Dissolution ◽

Solution Volume

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Glass as a Waste Form for the Immobilization of Plutonium

MRS Proceedings ◽

10.1557/proc-412-57 ◽

1995 ◽

Vol 412 ◽

Cited By ~ 19

Author(s):

J. K. Bates ◽

A. J. G. Ellison ◽

J. W. Emery ◽

J. C. Hoh

Keyword(s):

Silicate Glass ◽

Neutron Absorber ◽

Test Conditions ◽

Rate Of Reaction ◽

Processing Facility ◽

Surface Alteration ◽

Reaction With Water ◽

Tin Silicate ◽

Static Corrosion

AbstractSeveral alternatives for disposal of surplus plutonium are being considered. One method is incorporating Pu into glass and in this paper we discuss the development and corrosion behavior of an alkali-tin-silicate glass and update results in testing Pu doped Defense Waste Processing Facility (DWPF) reference glasses. The alkali-tin-silicate glass was engineered to accommodate a high Pu loading and to be durable under conditions likely to accelerate glass reaction. The glass dissolves about 7 wt% Pu together with the neutron absorber Gd, and under test conditions expected to accelerate the glass reaction with water, is resistant to corrosion. The Pu and the Gd are released from the glass at nearly the same rate in static corrosion tests in water, and are not segregated into surface alteration phases when the glass is reacted in water vapor. Similar results for the behavior of Pu and Gd are found for the DWPF reference glasses, although the long-term rate of reaction for the reference glasses is more rapid than for the alkalitin-silicate glass.

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Aem Analyses of SRL 131 Glass Altered as a Function of SA/V

MRS Proceedings ◽

10.1557/proc-257-73 ◽

1991 ◽

Vol 257 ◽

Cited By ~ 2

Author(s):

James J. Mazer ◽

John K. Bates ◽

Bruce M. Biwer ◽

C. R. Bradley

Keyword(s):

Experimental Studies ◽

Volume Ratio ◽

Scaling Factor ◽

Experimental Results ◽

Geologic Repository ◽

Short Term ◽

Natural Systems ◽

Test Conditions ◽

Solution Volume

Experimental studies of silicate glass/water reactions at low temperatures have previously identified the glass surface area-to-solution volume ratio (SA/V) as a significant rate determining parameter [1-4]. The value produced when SA/V is multiplied by reaction time, hereafter referred to as SVT, has been proposed as a scaling factor for comparing experimental results collected under different test conditions and for extrapolating short-term results to longer periods of time. Developing an understanding of the effect of SAN is needed for modeling experimental results where SA/V ranges in value or may vary during experiments. It is also useful to understand the effect of SA/V for modeling natural systems where this value almost certainly varies, such as during the hydrothermal diagenesis of natural glasses or projecting the long-term reaction of water and borosilicate nuclear waste glass in a geologic repository.

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An overview of simple basic equations used in HLW glass dissolution modeling: consequences for long term leaching and element profiles

MRS Proceedings ◽

10.1557/proc-932-82.1 ◽

2006 ◽

Vol 932 ◽

Cited By ~ 3

Author(s):

Marc Aertsens

Keyword(s):

Experimental Data ◽

Analytical Solution ◽

Water Solution ◽

Numerical Code ◽

Leach Rate ◽

Glass Dissolution ◽

Basic Assumptions ◽

Basic Equations ◽

The Relationship

ABSTRACTOver the last decades, several models describing glass dissolution have been published. Starting from the basic equations in their simplest form, the relationships between models are evaluated to address the following questions: 'What is the relationship between their basic assumptions?, What is the resulting long term leach rate? and, Which element profiles do they allow one to predict?' Although not part of it, this paper could complement the European project GLAMOR, where two models describing the dissolution of glass in a water solution, the r(t) and the GM models, are used by several groups to fit the same sets of experimental data. In this paper, other models are considered as well and all models are compared with each other.From comparison with the Boksay model, which uses the same equations, a simplification is suggested for the GM model concerning the water diffusion in the glass. The use of the numerical code developed to solve part of it, can mostly be avoided by using the analytical solution of the Boksay model.

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Classifying the Biological Status of Honeybee Workers Using Gas Sensors

Sensors ◽

10.3390/s21010166 ◽

2020 ◽

Vol 21 (1) ◽

pp. 166

Author(s):

Jakub T. Wilk ◽

Beata Bąk ◽

Piotr Artiemjew ◽

Jerzy Wilde ◽

Maciej Siuda

Keyword(s):

Gas Sensors ◽

Laboratory Tests ◽

Test Chamber ◽

Ambient Air ◽

True Positive Rate ◽

True Positive ◽

Positive Rate ◽

Parameters Of Accuracy ◽

Selection Of

Honeybee workers have a specific smell depending on the age of workers and the biological status of the colony. Laboratory tests were carried out at the Department of Apiculture at UWM Olsztyn, using gas sensors installed in two twin prototype multi-sensor detectors. The study aimed to compare the responses of sensors to the odor of old worker bees (3–6 weeks old), young ones (0–1 days old), and those from long-term queenless colonies. From the experimental colonies, 10 samples of 100 workers were taken for each group and placed successively in the research chambers for the duration of the study. Old workers came from outer nest combs, young workers from hatching out brood in an incubator, and laying worker bees from long-term queenless colonies from brood combs (with laying worker bee’s eggs, humped brood, and drones). Each probe was measured for 10 min, and then immediately for another 10 min ambient air was given to regenerate sensors. The results were analyzed using 10 different classifiers. Research has shown that the devices can distinguish between the biological status of bees. The effectiveness of distinguishing between classes, determined by the parameters of accuracy balanced and true positive rate, of 0.763 and 0.742 in the case of the best euclidean.1nn classifier, may be satisfactory in the context of practical beekeeping. Depending on the environment accompanying the tested objects (a type of insert in the test chamber), the introduction of other classifiers as well as baseline correction methods may be considered, while the selection of the appropriate classifier for the task may be of great importance for the effectiveness of the classification.

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Examination of some microbiological and biochemical parameters and tests of product quality used in a long-term fertilization trial

American Journal of Alternative Agriculture ◽

10.1017/s0889189300007827 ◽

1998 ◽

Vol 13 (3) ◽

pp. 138-144 ◽

Cited By ~ 2

Author(s):

Joachim Raupp

Keyword(s):

Food Storage ◽

Optimal Conditions ◽

Social Psychological ◽

Optimal Test ◽

Test Conditions ◽

Environmental Criteria ◽

Degradation Tests ◽

Reliable Parameter ◽

Chemical Contents

AbstractOn the basis of investigations with samples from a fertilization trial started in 1980, some parameters of food storage ability are evaluated. Microbial infestation of the product during incubation seems to be the most reliable parameter, but the circumstances of infestation and the optimal test conditions are unknown. There are no reliable correlations among the results of degradation tests, storage tests under optimal conditions, and chemical contents of the product. The concept of product vitality (a product-oriented quality referring to a product full of vigor) is based on results of degradation tests. Ultimately, however, food quality standards are based on human priorities (human-oriented). Therefore, not only product characteristics, but also social, psychological, and environmental criteria should be considered.

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Bone Regeneration by Novel Bioactive Glasses Containing Strontium and/or Magnesium: A Preliminary In-Vivo Study

Materials ◽

10.3390/ma11112223 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2223 ◽

Cited By ~ 12

Author(s):

Devis Bellucci ◽

Valeria Cannillo ◽

Alexandre Anesi ◽

Roberta Salvatori ◽

Luigi Chiarini ◽

...

Keyword(s):

Statistical Significance ◽

Formation Processes ◽

Complete Dissolution ◽

In Vitro Bioactivity ◽

Bioactive Glasses ◽

Beneficial Effects ◽

Glass Dissolution

In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in the literature. To simulate a long-term implant and to study the effect of the complete dissolution of glasses, samples were implanted in the mid-shaft of rabbits’ femur and analyzed 60 days after the surgery; such samples were in undersized powder form. The statistical significance with respect to the type of bioactive glass was analyzed by Kruskal–Wallis test. The results show high levels of bone remodeling, several new bone formations containing granules of calcium phosphate (sometimes with amounts of strontium and/or magnesium), and the absence of adverse effects on bone processes due to the almost complete glass dissolution. In vivo results confirming the cell culture outcomes of a previous study highlighted that these novel bioglasses had osteostimulative effect without adverse skeletal reaction, thus indicating possible beneficial effects on bone formation processes. The presence of strontium in the glasses seems to be particularly interesting.

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