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[en] The uranium ingot casting process is one of the steps which consolidate uranium deposits produced by electrorefiner in an ingot form in a pryprocessing technique. Since molten uranium metal reacts with a graphite crucible when the uranium is being dissolved, a graphite crucible cannot be used. Accordingly, a ceramic material must be selected which does not react with the dissolving uranium and this must be used as a coating material on the graphite crucible surface. As to this research, a reactivity experiments were performed between the coating layer and uranium by applying a thermal spray coating to the graphite material with alumina and YSZ ceramic material. As shown in the experimental result, the YSZ coating layer showed a stronger adhesive property on the side where there is no Ni-Al binding material. Moreover, no reaction was apparent between the YSZ coating layer and the uranium. Accordingly, the YSZ material and the process of thermal spray coating are considered to solve the reactive problem between uranium and a graphite crucible. (author)
[en] The fabrication of seamless tungsten crucibles 127-mm ID x 265-mm high x 6.25-mm wall thickness (5 in. x 10 1/2 in. x 1/4 in.) involved three drawing operations and extrusion spinning. The success of the drawing operations came from a combination of low draw reduction percentage, generous draw radii, large punch-to-die clearance, and attention to drawing temperature. The extrusion spinning success related to good drawn-cup-to-spinning-mandrel fit prior to making the extrusion passes, removal of stress risers in the part prior to spinning, and special attention to part and mandrel temperature
[en] This report documents the preliminary results of glass formulation and characterization accomplished within the finished scope of the EM-31 technology development tasks for WP-4 and WP-5, including WP-4.1.2: Glass Formulation for Next Generation Melter, WP-184.108.40.206: Systematic Glass Studies, and WP-220.127.116.11: Glass Formulation for Specific Wastes. This report also presents the suggested studies for eventual restart of these tasks. The initial glass formulation efforts for the cold crucible induction melter (CCIM), operating at ∼1200 C, with selected HLW (AZ-101) and LAW (AN-105) successfully developed glasses with significant increase of waste loading compared to that is likely to be achieved based on expected reference WTP formulations. Three glasses formulated for AZ-101HLW and one glass for AN-105 LAW were selected for the initial CCIM demonstration melter tests. Melter tests were not performed within the finished scope of the WP-4.1.2 task. Glass formulations for CCIM were expanded to cover additional HLWs that have high potential to successfully demonstrate the unique advantages of the CCIM technologies based on projected composition of Hanford wastes. However, only the preliminary scoping tests were completed with selected wastes within the finished scope. Advanced glass formulations for the reference WTP melter, operating at ∼1200 C, were initiated with selected specific wastes to determine the estimated maximum waste loading. The incomplete results from these initial formulation efforts are summarized. For systematic glass studies, a test matrix of 32 high-aluminum glasses was completed based on a new method developed in this study.
[en] The crucibles used currently for microwave melting of U-Mo alloy at the Y-12 Complex contain silicon carbide (SiC) in a mullite (3Al2O3-2SiO2) matrix with an erbia coating in contact with the melt. Due to observed silicon contamination, Pacific Northwest National Laboratory has investigated alternative crucible materials that are susceptible to microwave radiation and are chemically compatible with molten U-Mo at 1400 1500C. Recommended crucibles for further testing are: 1) high-purity alumina (Al2O3); 2) yttria-stabilized zirconia (ZrO2); 3) a composite of alumina and yttria-stabilized zirconia; 4) aluminum nitride (AlN). Only AlN does not require an erbia coating. The recommended secondary susceptor, for heating at low temperature, is SiC in a “picket fence” arrangement.
[en] The purposes of this work were to demonstrate the evaporation of AZ-102 supernate, demonstrate the vitrification of the evaporated concentrate in a crucible melt, and to demonstrate acceptance of the resulting glass by analysis (chemical and radionuclides) and durability testing
[en] In the cold crucible induction melter(CCIM), bubblers are installed to efficiently mix wastes such as dry active waste and resin with motlen glass to obtain high-quality stable glass solid. In this study, the thermal flow field is visualized in the CCIM according to the position of the bubbler, and the influence of the position of the bubbler on the flow of the molten glass in the CCIM is examined. Previously, study was the thermal- flow analysis inside the CCIM. The effect of the position of the bubbler on the flow of the molten glass inside the CCIM was analyzed by visualizing the thermal-flow field according to the position of the bubbler.
[en] The EMIS PARSIFAL can work with two different sources: A thermoionization source or a plasma source. For the former, the work function of tungsten crucibles is enhanced by previous heating at 2850deg C for two hours. Outgassing of both source types after cleaning required days' occupancy of PARSIFAL. A special bench, a copy of the separator source block with its supplies, was designed and built for these purposes in 1990. The Dollar 170 000 investment relieves PARSIFAL from secondary tasks and saves approximately 60 days per year. (orig.)
[en] Designing a measurement system that might be used in a nuclear facility is a challenging, if not daunting, proposition. The situation is made more complicated when the system needs to be designed to satisfy the disparate requirements of a monitoring and a host party - a relationship that could prove to be adversarial. The cooperative design of the elements of the AVNG (Attribute Verification with Neutrons and Gamma Rays) system served as a crucible that exercised the possible pitfalls in the design and implementation of a measurement system that could be used in a host party nuclear facility that satisfied the constraints of operation for both the host and monitoring parties. Some of the issues that needed to be addressed in the joint design were certification requirements of the host party and the authentication requirements of the monitoring party. In this paper the nature of the problem of cooperative design will be introduced. The details of cooperative design revolve around the idiosyncratic nature of the adversarial relationship between the parties involved in a possible measurement regime, particularly if measurements on items that may contain sensitive information are being pursued. The possibility of an adversarial interaction is more likely if an information barrier is required for the measurement system. The origin of the antagonistic elements of the host party and hosted party relationship will be considered. In addition, some of the conclusions will be presented that make cooperative design (and development) proceed more efficiently. Finally, some lessons learned will be presented as a result of this expedition into cooperative design.
[en] Quartz is used for extraction of silicon and also for making crucibles as heating pot to melt high temperature semiconductors during crystal growth. Quartz crucible purity is of great concern for crystals grown by Czochralski technique (CZ). During growth, impurities critical from semiconductor point of view are incorporated into the from of crucible and degrade the quality of the crystal. The impurities in quartz crucible used for growing single crystal at NIST are determined by using atomic absorption spectroscopy. (author) 5 figs