Joule-Heated Ceramic-Lined Melter to Vitrify Liquid Radioactive Wastes Containing Am241 Generated From MOX Fuel Fabrication in Russia

Joule-Heated Ceramic-Lined Melter to Vitrify Liquid Radioactive Wastes Containing Am241 Generated From MOX Fuel Fabrication in Russia
Author: E. C. Smith
Publisher:
Total Pages:
Release: 2004
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ISBN:

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The governments of the United Stated of America and the Russian Federation (RF) signed an Agreement September 1, 2000 to dispose of weapons plutonium that has been designated as no longer required for defense purposes. The Agreement declares that each country will disposition 34MT of excess weapons grade plutonium from their stockpiles. The preferred disposition technology is the fabrication of mixed oxide (MOx) fuel for use or burning in pressurized water reactors to destroy the plutonium. Implementation of this Agreement will require the conversion of plutonium metal to oxide and the fabrication of MOx fuel within the Russian Federation. The MOx fuel fabrication and metal to oxide conversion processes will generate solid and liquid radioactive wastes containing trace amounts of plutonium, neptunium, americium, and uranium requiring treatment, storage, and disposal. Unique to the Russian MOx fuel fabrication facility's flow-sheet is a liquid waste stream with high concentrations ({approx}1 g/l) of {sup 241}Am and non radioactive silver. The silver is used to dissolve PuO{sub 2} feed materials to the MOx fabrication facility. Technical solutions are needed to treat and solidify this liquid waste stream. Alternative treatment technologies for this liquid waste stream are being evaluated by a Russian engineering team. The technologies being evaluated include borosilicate and phosphate vitrification alternatives. The evaluations are being performed at a conceptual design level of detail under a Lawrence Livermore National Laboratory (LLNL) contract with the Russian organization TVEL using DOE NA-26 funding. As part of this contract, the RF team is evaluating the technical and economic feasibility of the US borosilicate glass vitrification technology based on a Duratek melter to solidify this waste stream into a form acceptable for storage and geologic disposal. The composition of the glass formed from treating the waste is dictated by the concentration of silver and americium it contains. Silver is widely used as an additive in glass making. However, its solubility is known to be limited in borosilicate glasses. Further, silver, which is present as a nitrate salt in the waste, can be easily reduced to molten silver in the melting process. Molten silver, if formed, would be difficult to reintroduce into the glass matrix and could pose operating difficulties for the glass melter. This will place a limitation on the waste loading of the melter feed material to prevent the separation of silver from the waste within the melter. If the silver were recovered in the MOx fabrication process, which is currently under consideration, the composition of the glass would likely be limited only by the thermal heat load from the incorporated {sup 241}Am. The resulting mass of glass used to encapsulate the waste could then be reduced by a factor of approximately three. The vitrification process used to treat the waste stream is proposed to center on a joule-heated ceramic lined slurry fed melter. Glass furnaces of this type are used in the United States to treat high-level waste (HLW) at the: Defense Waste Processing Facility, West Valley Demonstration Project, and to process the Hanford tank waste. The waste will initially be blended with glass-forming chemicals, which are primarily sand and boric acid. The resulting slurry is pumped to the melter for conversion to glass. The melter is a ceramic lined metal box that contains a molten glass pool heated by passing electric current through the glass. Molten glass from the melter is poured into canisters to cool and solidify. They are then sealed and decontaminated to form the final waste disposal package. Emissions generated in the melter from the vitrification process are treated by an off-gas system to remove radioactive contamination and destroy nitrogen oxides (NOx).

Design and Operation of High Level Waste Vitrification and Storage Facilities

Design and Operation of High Level Waste Vitrification and Storage Facilities
Author: International Atomic Energy Agency
Publisher:
Total Pages: 114
Release: 1992
Genre: Business & Economics
ISBN:

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This report gives an up to date review of high level waste vitrification and storage facilities currently in an advanced stage of implementation.

Experience with a Joule Heated Ceramic Melter While Converting Simulated High-level Waste to Glass

Experience with a Joule Heated Ceramic Melter While Converting Simulated High-level Waste to Glass
Author:
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Total Pages:
Release: 1976
Genre:
ISBN:

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Development of a joule-heated ceramic melter, sponsored by the Energy Research and Development Administration, has been progressing for nearly 3 years. In January 1975, a ceramic-lined, direct joule-heated glass melter was started up and operated continuously for nearly 11 months. During this period, process testing was completed both while feeding simulated high-level waste calcine and while feeding simulated high-level liquid waste. While feeding waste calcine and frit, the unit was demonstrated at a production rate in excess of 45 kg of glass/hour, which meets the needs of a reference 5 MTU/day reprocessing plant. When the simulated liquid waste and frit slurry were fed to the system, a 25-liter/hr process rate was demonstrated. This capacity is equivalent to the needs of a 1.5 MTU/day reprocessing plant. Evaluation of the melter after 10.8 months of operation suggests that a melter life in excess of 2 years is likely. The operation of the engineering-scale ceramic melter has been encouraging. The high capacity of the melter with the capability for direct liquid feeding and a long operating life suggests that a joule-heated ceramic melter will play a major role in future waste solidification processes.

Experimental Joule-heated Ceramic Melter for Converting Radioactive Waste to Glass

Experimental Joule-heated Ceramic Melter for Converting Radioactive Waste to Glass
Author:
Publisher:
Total Pages:
Release: 1978
Genre:
ISBN:

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A small electric melter was developed to implement studies for converting radioactive waste to glass at the Savannah River Laboratory (SRL). The ceramic-lined, joule-heated melter has been in operation for ten months. During this period, simulated, high-level-waste, calcined materials and frit were processed at rates of 2 to 15 g/min. The melt chamber is 7.6-cm wide, 22.9-cm long and 7.6-cm deep. The total power consumption is 3.5 KVA when the glass processing temperature is 1150°C. A similar unit will be in operation in FY-1979 in the SRL high-level cells.

GLASS-CERAMICS IN A COLD-CRUCIBLE MELTER

GLASS-CERAMICS IN A COLD-CRUCIBLE MELTER
Author: R. A. DAY
Publisher:
Total Pages: 12
Release: 2003
Genre:
ISBN:

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Improving the efficiency of nuclear waste immobilization is constantly desired by all nuclear waste management programs world-wide. For high-level and other waste to be vitrified in traditional ceramic Joule-heated melters operated at temperatures up to 1150 C, process flexibilities including waste loadings are often restricted by this temperature limit as well as the need to consider wasteform corrosion of refractory linings and electrodes. New melter technologies, such as the cold-crucible melter (CCM), enable processing up to significantly higher temperatures free of many of the limitations of conventional melters. Higher processing temperatures open up the way for wider composition and processing envelopes to be considered for the vitrification process, including the possibility for higher waste loadings. In many instances the presence of crystals in the final cooled wasteform is not considered desirable within presently existing glass specifications. For some feed compositions in creased waste loadings can lead to the formation of large amounts of crystals, and thus to a significant departure from the ''glass'' state. Nevertheless it is recognized that, in general, increasing the acceptable volume fractions of crystals in the glass offers the best opportunity to increase waste loading, all other factors being equal. In addition, the deliberate promotion of specific crystalline phases by design may enhance the quality of the wasteform, for example by partitioning a long-lived radionuclide into a very stable crystalline phase, or by depleting the glass in detrimental elements. In order to explore the potential improvements by harnessing the higher achievable processing temperatures and immunity to refractory corrosion available with the cold-crucible melter, and after promising indications for synroc-based matrices, it was decided to investigate the feasibility of designing and producing via melting new high temperature ''glass-ceramic'' wasteforms for high level was te immobilization. The INEEL calcines were selected as example feed compositions. These calcines have a wide range of problematic compositions. They either have high amounts of crystal-forming components, and/or components that lead to corrosive melts, and for good measure, the components in some waste types are quite refractory for vitrification as well. The recent DOE High-Level Waste Melter Review Report concluded that, for the INEEL calcine wastes in particular, the CCM could have sufficient advantages over the Joule-heated ceramic melter to justify its evaluation for direct vitrification of these wastes. Based on the extensive ceramic design experience of ANSTO, in collaboration with the CEA and COGEMA for a CCM implementation, a preliminary set of waste forms has been developed that immobilize long-lived waste actinides into highly chemically durable crystalline phases by design, using refractory crystal-forming components already in the wastes to advantage, while at the same tim e maintaining a very good overall leach resistance for the glass-ceramics even after ''canister centerline cooling'' (CCC) heat treatments. This paper presents the results of a 50 kg technological scale test in the CCM of a glass-ceramic formulation for the average Bin Set 2 formulation, at a conservative waste loading of 50%.

Experience with Waste Vitrification Systems at Battelle-Northwest

Experience with Waste Vitrification Systems at Battelle-Northwest
Author:
Publisher:
Total Pages:
Release: 1975
Genre:
ISBN:

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Three types of melters; in-can, continuous metallic, and joule-heated ceramic are being developed on an engineering scale for conversion of simulated high-level radioactive waste to a glass form. Work with each of the three melters has progressed for over a year, and ton quantities of glass have been produced. The operation and performance of these systems are described. (auth).

Vitrification of SRP Waste by a Slurry-fed Ceramic Melter

Vitrification of SRP Waste by a Slurry-fed Ceramic Melter
Author:
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Total Pages:
Release: 1980
Genre:
ISBN:

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Savannah River Plant (SRP) high-level waste (HLW) can be vitrified by feeding a slurry, instead of a calcine, to a joule-heated ceramic melter. Potential advantages of slurry feeding include (1) use of simpler equipment, (2) elimination of handling easily dispersed radioactive powder, (3) simpler process control, (4) effective mixing, (5) reduced off-gas volume, and (6) cost savings. Assessment of advantages and disadvantages of slurry feeding along with experimental studies indicate that slurry feeding is a promising way of vitrifying waste.