Thermodynamic modelling of nuclear waste glasses

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To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. For the handling of high level nuclear waste HLWnew glass formulations with a high waste capacity and an enhanced thermal stability, chemical durability, and processability are under consideration. To qualify the behavior of such a peraluminous glass in a geological storage situation, its chemical durability was studied in various environments pure water, groundwater, and alkaline solutions related to a cement environment and glass alteration regimes initial rate, residual rate, and resumption of alteration.

The alteration solution was characterized by inductively coupled plasma, and the altered glass by scanning electron microscopy, X-ray diffraction and secondary ion mass spectrometry. A comparative study of the chemical durability of these and reference glasses ISG and SON68 over all timescales highlights the remarkable properties of the former.

While their initial dissolution rate is of the same order as the reference glasses, the gel formed under silica saturation conditions is more passivating, making its dissolution rate at least one order of magnitude lower, while its low alkalinity makes it less susceptible to clayey groundwater and highly alkaline solutions.

In France, high level nuclear waste is currently immobilized in R7T7 borosilicate glass. The standard procedure for the management of these waste packages over geological time scales is to store them in a deep, low permeability and stable geological formation, such as the Callovo-Oxfordian COx claystone that France could choose. R7T7 glass can hold up to To limit the number of vitrified canisters produced, new glass matrices with a higher waste capacity are under study.

The glass network and the structural role of the REs differ substantially in these two composition ranges. The alkaline and alkaline-earth elements thus act both as charge compensators and as network modifiers in the peralkaline domain, but principally as charge compensators in the peraluminous domain. The solubility of lanthanides, substantially higher in peraluminous glasses, and their tendency to crystallize, also appear to be strongly dependent on the R P ratio.

The resistance of glass to aqueous alteration is not an intrinsic property of the material, but is rather the response of glass to a range of environmental factors.

thermodynamic modelling of nuclear waste glasses

This initial dissolution period or Stage Icontinues as long as there is no feedback effect of dissolved elements on the glass dissolution rate. In a given solution pH, ionic strength at a fixed temperature, the initial alteration rate r 0 is the fastest. Mechanisms and their associated dissolution rates during Stages II and III are mostly governed by the secondary phases that precipitate as the glass degrades, which in turn depend on the composition of the glass and environmental conditions—in particular the composition of the surrounding solution, its renewal rate and the presence of iron and iron corrosion products in the vicinity of the glass.

To acquire an overall understanding of the long-term behavior of peraluminous glasses, the alteration of a peraluminous reference glass, called G0. The results obtained are compared herein with those in the literature for peralkaline glasses, in particular ISG, the reference standard for the long-term behavior of nuclear glasses, 4647 and SON68, the radiologically inactive surrogate of the French R7T7 reference nuclear glass.

In most studies on borosilicate glass durability, boron is selected as the glass alteration tracer as it is highly soluble and not incorporated in the alteration products.

After a leaching period of two months of the G0. For silicon and aluminum, this retention is similar to what is observed in peralkaline glasses in which these two elements are involved in the formation of the gel. H profile, due to water and hydroxyl groups in the altered layer, is not normalized. For experiments in pure water, sodium can be used as an alteration tracer for G0. For experiments performed in COx water or in alkaline solutions, sodium is involved in the formation of secondary phases and thus cannot be used as a dissolution tracer.

For these experiments, the probably underestimated dissolution rates calculated from boron release rates are given with the caveat that this element is partially retained in the altered layer. Figure 2 shows the equivalent alteration thicknesses measured as a function of time for G0.

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The initial dissolution rates calculated for Si, Al, B, and Na are 0. Initial dissolution rates in pure water. Figure 3 shows the time evolution of the equivalent alteration thicknesses of Si, Al, B, and Na for a static alteration test of G0. The dissolution rate then decreases slowly. Residual rates in pure water. The dissolution rates calculated between the th and th day for Na and B are 2.

The pH over this period was stable at around 8. Figure 4 shows the time evolution of the equivalent alteration thickness of boron, and the magnesium and silicon concentrations, as well as the variation of the pH of the solution during peraluminous G0. The magnesium and silicon concentrations both decrease, the former significantly Supplementary Table 3.Studies aimed primarily at determining leach rates of different elements from doped glasses have resulted in computerized models for predicting leachate concentrations.

However, leach rate related data should be limited to predicting the stability behavior of the glass matrix; the radionuclide release data based on these studies are empirical and are highly dependant on many variables and processes which have not been systematically evaluated and thus do not provide a reliable method of predicting leachate concentrations.

This alternate approach relies on the experimental solubilities of pulverized doped glasses, in a wide range of well-controlled important variables such as pH and pe, and their comparisons at the given aqueous composition to predicted solubilities of known solid phases from the thermodynamic data.

This paper summarizes data available for the application of this alternate approach to reliably predict concentrations of thorium, uranium, neptunium, plutonium, and trivalent actinides and rare earth elements leachable from the doped glasses. The thermodynamic data, in addition to that reported in recent critical reviews, includes new data that were developed for the solubility products of Th 3 PO 4 4 s and the solid solutions of trivalent actinides and rare earth hydroxides.

Needed future research in this area is briefly outlined. This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. Ribet, I. Grambow, B. McGrail, B. Advocat, T. Ashida, T. Bates, J.

Bosbach, D. Kienzler, B. Waste Manag. Kohara, Y.

thermodynamic modelling of nuclear waste glasses

Menard, O. Miyahara, K. Nakayama, S. Pierce, E. Pirlet, V. Wellman, D.November 3, Bates, Rutgers University. How do you handle nuclear waste that will be radioactive for millions of years, keeping it from harming people and the environment?

It isn't easy, but Rutgers researcher Ashutosh Goel has discovered ways to immobilize such waste — the offshoot of decades of nuclear weapons production — in glass and ceramics. Goel, an assistant professor in the Department of Materials Science and Engineering, is the primary inventor of a new method to immobilize radioactive iodine in ceramics at room temperature. Developing ways to immobilize iodine, which is especially troublesome, is crucial for its safe storage and disposal in underground geological formations.

The half-life of iodine is Environmental Protection Agency. If it's released into the environment, iodine will linger for millions of years. Iodine targets the thyroid gland and can increase the chances of getting cancer. Among Goel's major funders is the U. Department of Energy DOEwhich oversees one of the world's largest nuclear cleanups following 45 years of producing nuclear weapons.

Chemical durability of peraluminous glasses for nuclear waste conditioning

The national weapons complex once had 16 major facilities that covered vast swaths of Idaho, Nevada, South Carolina, Tennessee and Washington state, according to the DOE. The agency says the Hanford site in southeastern Washington, which manufactured more than 20 million pieces of uranium metal fuel for nine nuclear reactors near the Columbia River, is its biggest cleanup challenge.

Hanford plants processedtons of fuel from the reactors. Some 56 million gallons of radioactive waste — enough to fill more than 1 million bathtubs — went to large underground tanks. As many as 67 tanks — more than one third — are thought to have leaked, the DOE says. The liquids have been pumped out of the 67 tanks, leaving mostly dried solids. The Hanford cleanup mission commenced inand construction of a waste treatment plant for the liquid radioactive waste in tanks was launched a decade later and is more than three-fifths finished.

Goel, a native of Punjab state in northern India, earned a doctorate in glasses and glass-ceramics from the University of Aveiro in Portugal in and was a postdoctoral researcher there. He worked as a "glass scientist" at the Pacific Northwest National Laboratory in andand then as a senior scientist at Sterlite Technologies Ltd.

One of his inventions involves mass producing chemically durable apatite mineralsor glasses, to immobilize iodine without using high temperatures.

thermodynamic modelling of nuclear waste glasses

A second innovation deploys synthesizing apatite minerals from silver iodide particles. He's also studying how to immobilize sodium and alumina in high-level radioactive waste in borosilicate glasses that resist crystallization. At the Hanford site, creating glass with radioactive waste is expected to start in around orGoel said, and "the implications of our research will be much more visible by that time.

The research may eventually help lead to ways to safely dispose of highly radioactive spent nuclear fuel that is stored now at commercial nuclear power plants.

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By using our site, you acknowledge that you have read and understand our Privacy Policy and Terms of Use.AbstractAmong the large number of matrixes explored as hosts for high-level nuclear wastes, conditioning of fission products and minor actinides into a homogeneous borosilicate glass is the most promising technique already implemented at the industrial scale.

The advantage of this vitrification process is the volume reduction of the high level waste coming from the spent fuel reprocessing and its stability for the long-term storage. In order to point out the chemical interactions between the glass and these precipitated phases issuing from the calcinated waste, a thermodynamic approach is developed using the Calphad method.

Danger! Radioactive Waste -- Full Program

The objective of this work is to calculate thermodynamic properties for complex fission product systems in order to predict the precipitation of platinoids or molybdate phases. This flexible tool enables to predict phase diagrams, composition and relative stability of the metallic or oxide precipitated phases as a function of both temperature and oxygen potential in the glass melt.

Location of Repository. Bordier, S. Schuller, A. Laplace and J. Provided by: Elsevier - Publisher Connector. Suggested articles.Search this site Search this site. This is required in order to make the nuclear industry sustainable and is also necessary for the environmental reasons due to large amount of legacy waste already accumulated.

We model new types of glasses as encapsulation matrices and perform state-of-the-art molecular dynamics simulations to understand the stability of glasses and their suitability for long-term encapsulation of nuclear waste. We calculate several important properties of novel glass compositions including the activation energy for crystallization and phase separation as well as structure.

We compare our results with the structural and thermodynamic experiments performed by our US partners. This will enable us to gain atomistic understanding of what governs stability of glasses at the microscopic level and predict their long-term performance. Modelling of glasses as nuclear waste forms. Trachenko, Professor K.

Dove, Professor MT. Queen Mary University of London. Standard Research - NR1. Energy - Nuclear. Panel Date.

Summary on Grant Application Form. This proposal addresses the pressing need to find suitable methods to safely encapsulate nuclear waste. Key Findings. Potential use in non-academic contexts. Sectors submitted by the Researcher.Disabling it will result in some disabled or missing features. You can still see all customer reviews for the product. But with so many terrific random digits, it's a shame they didn't sort them, to make it easier to find the one you're looking for.

It lists almost 600 integers in numerical order. ByObi Wanon January 27, 2015I was duped by the title of this book. It is supposed to be about random digits. And at first glance you do see randomness. But after reading the book a while I started seeing a pattern. I did extensive research to prove my theory. After hours of mathematical modeling I conclusively proved that there is a set of numbers in this book that it not only a pattern, but is outright sequential.

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Can radioactive waste be immobilized in glass for millions of years?

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Guidelines Sign in to comment Showing 0 commentsSort by: Newest Oldest There was a problem loading comments right now. If you look closely, you will note that every tenth digit or so is just a repeat of the last digit and every hundredth or so is a just the same digit repeated three times. A sampling of this "work":Page 36 - Line 6 - 15 characters in should be 5, not 4. Page 99 - Line 18 - first three characters should be "453" not "345". Page 145 - Line 2 - 7th and 19th characters transposed.

Page 190 - Whole line of numbers omitted betwen 6th and 7th lines. Pages 210 and 211 - Two sections appear quasi-randomized, instead of randomized. Also, if you stare at it long enough, you can decode something around page 300 about Jody Foster and J. Salinger giving me some sort of instructions. I'm going to stay up another couple nights staring at this to see if I can make out anything further.

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