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Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
We identify the state of the art, gaps in current understanding, and key research needs in the area of modeling the long-term degradation of ceramic waste forms for nuclear waste disposition. The directed purpose of this report is to define a roadmap for Waste IPSC needs to extend capabilities of waste degradation to ceramic waste forms, which overlaps with the needs of the subconsinuum scale of FMM interests. The key knowledge gaps are in the areas of (i) methodology for developing reliable interatomic potentials to model the complex atomic-level interactions in waste forms; (ii) characterization of water interactions at ceramic surfaces and interfaces; and (iii) extension of atomic-level insights to the long time and distance scales relevant to the problem of actinide and fission product immobilization.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
We identify the state of the art, gaps in current understanding, and key research needs in the area of modeling the long-term degradation of ceramic waste forms for nuclear waste disposition. The directed purpose of this report is to define a roadmap for Waste IPSC needs to extend capabilities of waste degradation to ceramic waste forms, which overlaps with the needs of the subconsinuum scale of FMM interests. The key knowledge gaps are in the areas of (i) methodology for developing reliable interatomic potentials to model the complex atomic-level interactions in waste forms; (ii) characterization of water interactions at ceramic surfaces and interfaces; and (iii) extension of atomic-level insights to the long time and distance scales relevant to the problem of actinide and fission product immobilization.
Author: W. L. Bourcier Publisher: ISBN: Category : Languages : en Pages : 17
Book Description
Not all the nuclear waste destined for Yucca Mountain is in the form of spent fuel. Some of it will be radioactive waste generated from the production of nuclear weapons. This so-called defense waste exists mainly as corrosive liquids and sludge in underground tanks. An essential task of the U.S. high-level radioactive waste program is to process these defense wastes into a solid material--called a waste form. An ideal waste form would be extremely durable and unreactive with other repository materials. It would be simple to fabricate remotely so that it could be safely transported to a repository for permanent storage. What's more, the material should be able to tolerate exposure to intense radiation without degradation. And to minimize waste volume, the material must be able to contain high concentrations of radionuclides. The material most likely to be used for immobilization of radioactive waste is glass. Glasses are produced by rapid cooling of high-temperature liquids such that the liquid-like non-periodic structure is preserved at lower temperatures. This rapid cooling does not allow enough time for thermodynamically stable crystalline phases (mineral species) to form. In spite of their thermodynamic instability, glasses can persist for millions of years. An alternate to glass is a ceramic waste form--an assemblage of mineral-like crystalline solids that incorporate radionuclides into their structures. The crystalline phases are thermodynamically stable at the temperature of their synthesis; ceramics therefore tend to be more durable than glasses. Ceramic waste forms are fabricated at temperatures below their melting points and so avoid the danger of handling molten radioactive liquid--a danger that exists with incorporation of waste in glasses. The waste form provides a repository's first line of defense against release of radionuclides. It, along with the canister, is the barrier in the repository over which we have the most control. When a waste form is designed, the atomic environment of the radionuclides is chosen to maximize chemical durability. Elements such as zirconium and phosphorus can be included in the waste form that react with and make some radionuclides less soluble and therefore less likely to be released. The long-term performance assessment of radionuclide containment requires the development of models for each part of the barrier system. It is almost certainly easier to model the corrosion and alteration of waste forms than it is to develop coupled hydrologic, chemical, and geophysical models of radionuclide transport away from a repository. Therefore, much time and effort has been spent optimizing the chemical durability of both glass and ceramic waste forms for radionuclide containment. This has not been an easy task. Three problems in particular posed the greatest challenges. The first is that radionuclides decay, transmuting into daughter elements that may have different chemical properties. These new elements might degrade the existing mineral by making it unstable. A good waste form that works well for uranium may work poorly for lead, its final decay product. The second problem is that the radioactive decay itself damages the solid over time. Radioactive decay is an energetic process in which ejected particles and the recoiling nucleus disrupt the surrounding atoms. A single alpha-decay event can displace thousands of atoms in the surrounding volume. We know from laboratory measurements that radionuclides are more easily released from radiation-damaged structures than from materials that do not sustain radiation damage. The third problem is that radioactive waste, particularly the high level waste from reprocessing of spent nuclear fuel to extract plutonium and uranium, contains a variety of elements with widely varying chemistry. The waste form must incorporate the radionuclides, as well as non-radioactive elements such as silicon and sodium that are present in the waste stream as a result of waste processing. A number of ceramic waste forms have been developed that minimize these problems and provide a potentially useful host for radionuclides. For ceramics, the mineralogy can be tailored to the waste stream by selecting solid mineral phases with structural sites that can accommodate the waste elements, as well as newly formed radioactive decay elements. Radiation damage can be minimized by selecting mineral phases that allow atoms to renew or regain their original crystalline structure, a process known as annealing. For example, actinide phosphate minerals anneal more readily than actinide silicate minerals. Despite the superior thermodynamic stability of crystalline materials, borosilicate glasses have become the preferred waste forms. One reason is that the processing technologies associated with this glass are believed to be easier to adapt to handling highly radioactive material.
Author: Dennis F. Bickford Publisher: ISBN: 9780944904794 Category : Technology & Engineering Languages : en Pages : 530
Book Description
Presents papers from a symposium on environmental and waste management issues in the ceramic industry at the April 1994 meeting. Topics include waste management/environmental solutions using ceramics, modeling and mechanisms of waste form dissolution, properties and characteristics of wastes and was
Author: Gary L. Smith Publisher: John Wiley & Sons ISBN: 1118371453 Category : Technology & Engineering Languages : en Pages : 389
Book Description
Composed from two symposia conducted at the 2001 Annual Meeting of The American Ceramic Society, this new volume details the advances in the state of knowledge in nuclear and waste materials science and technology. Highlighted are areas of rapid change such as in the application, development, and testing of ceramics and glasses in the nuclear and waste industries. As companies begin to focus on ¿green ceramics¿ and the manufacturing of environmentally friendly products, the development of innovative processing approaches and novel environmental treatment technologies soon follows. These are being developed to address more stringent regulations and to obtain an improved scientific understanding of the industrial processes and treatment technologies. This seventh volume in the series addresses current nuclear and environmental problems and provides solutions for them. It is an excellent resource for researchers and scientists involved in the ceramic and nuclear industries. roceedings of the symposium held at the 103rd Annual Meeting of The American Ceramic Society, April 22-25, 2001, in Indiana; Ceramic Transactions, Volume 132.
Author: John D. Vienna Publisher: John Wiley & Sons ISBN: 1118407024 Category : Technology & Engineering Languages : en Pages : 384
Book Description
In today's world of increasingly stringent environmental regulations, it is critical to identify and adequately address environmental issues in the ceramic industry to ensure success. In addition, ceramics and glasses play a critical role in the nuclear industry. Nuclear fuels and waste forms for low-level and high-level radioactive, mixed, and hazardous wastes are primarily either ceramic of glass. Effective and responsible environmental stewardship is becoming increasingly more important in the world. These proceedings detail the results of the ongoing effort in these areas. Proceedings of the symposium held at the 105th Annual Meeting of The American Ceramic Society, April 27-30, in Nashville, Tennessee; Ceramic Transactions, Volume 155.
Author: Vijay Jain Publisher: ISBN: Category : Technology & Engineering Languages : en Pages : 552
Book Description
The 52 contributions explore technical issues involving the use of ceramic materials in the storage of nuclear waste. The main themes are vitrification operations and testing, waste form modeling, the development of alternative waste forms, environmental solutions, waste form durability, cement wast
Author: S. K. Sundaram Publisher: John Wiley & Sons ISBN: 1118406001 Category : Technology & Engineering Languages : en Pages : 398
Book Description
Papers in this volume illustrate the delicate balance that exists among the environment, the processes/technologies that have been used in glass and ceramic industries, as well as the wastes - both nuclear and non-nuclear (hazardous) - that have been generated. This book helps to foster continued scientific understanding, technological growth, and environmental stewardship within the fields of ceramics, glass, and environmental/nuclear engineering. Proceedings of the symposium held at the 104th Annual Meeting of The American Ceramic Society, April 28-May1, 2002 in Missouri; Ceramic Transactions, Volume 143.
Author: Publisher: ISBN: Category : Radioactive waste disposal in the ground Languages : en Pages : 524
Book Description
The purpose of this environmental impact statement (EIS) is to provide information on potential environmental impacts that could result from a Proposed Action to construct, operate and monitor, and eventually close a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste at the Yucca Mountain site in Nye County, Nevada. The EIS also provides information on potential environmental impacts from an alternative referred to as the No-Action Alternative, under which there would be no development of a geologic repository at Yucca Mountain.
Author: Dennis F. Bickford Publisher: Amer Ceramic Society ISBN: 9780944904794 Category : Technology & Engineering Languages : en Pages : 504
Book Description
Presents papers from a symposium on environmental and waste management issues in the ceramic industry at the April 1994 meeting. Topics include waste management/environmental solutions using ceramics, modeling and mechanisms of waste form dissolution, properties and characteristics of wastes and was
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Author: W. L. Bourcier
Author: Dennis F. Bickford
Author: Gary L. Smith
Author: John D. Vienna
Author: Vijay Jain
Author: S. K. Sundaram
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Author: Dennis F. Bickford