Limited Increase of Particle Entrainment in the Off-Gas System of a Cold Crucible Induction Melter Compared with a Joule-Heated Metal Melter for HLLW Vitrification -11465

ABSTRACT Fission product solutions arising from reprocessing spent fuel from the nuclear reactors used for electrical production in France are immobilized in six vitrification lines at the AREVA La Hague plant. In 2010, the conventional Joule-heated metal melter was replaced in one of these six lines with a cold crucible melter. The cold crucible melter began vitrifying radioactive effluents produced by rinsing operations in legacy facilities in April 2010. The composition of these effluents requires a containment glass synthesis temperature that exceeds the operating temperatures limits of conventional ("hot") melters. The cold crucible melter technology has three main advantages: melt temperatures well above the current limit, increased glass production capacity, extended lifetime because of the lower wall temperatures. For these reasons the cold crucible melter can subsequently be used to vitrify a wide range of High-Level Liquid Waste (HLLW). This paper describes the assessment performed to characterize the entrainment of particles or chemicals and/or radioactive species to the off-gas treatment system from a Joule-heated metal melter (JHMM) and from a cold crucible induction melter (CCIM). Vitrification is performed in a two-step process. A calciner is used in each case to dry and calcine the high-level liquid waste, supplying only the dry residue to the melter together with glass frit. The off-gas treatment is identical for both melters. The paper first describes how the CEA uses its reconfigurable vitrification prototype, a full-scale mockup of a La Hague vitrification line, in support of AREVA to anticipate cold crucible melter operation under radioactive conditions. It describes the process equipment constituting the vitrification line from the melter (using a JHMM or a CCIM) to the off-gas treatment system. All the differences that contribute to the modification of radioactive particle entrainment from the calciner/melter to the off-gas treatment system are then described. The results obtained are then discussed concerning the volatility of species produced by vitrification during weekly tests implementing either the conventional melting pot or the cold crucible melter. The distribution of volatile species in the off-gas treatment devices is discussed. The paper concludes with a discussion of how using the CCIM vitrification process on one of the La Hague vitrification units can achieve an increased vitrification throughput at a higher temperature without any impact on the resulting waste release

Rapid scanning spectrometric study of the transient species

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Contribution of the Numerical Simulations in the Development of the French HLLW Vitrification Processes

International audienceFor many years, the CEA (Commissariat à l'Énergie Atomique et aux Énergies Alternatives) Marcoule and AREVA have developed various processes dedicated to radioactive waste confinement, especially vitrification processes for HLLW. For 10 years now, the numerical simulation has become an important tool for research and developement projects held in the CEA-AREVA Joint Vitrification Laboratory (LCV). Induction heating, fluid mechanics and thermal simulations take part of all new R&D projects. The apports of such simulations are, first, the enhancement of the working knowledge of existing process. Those data are very useful to define optimisation choices, for example upgrades made on the hot metallic melter used since the 1990s at LaHague facility. Second, the simulations are, of course, also used at the conception stage of new processes as a tool allowing wide ranges parametric tests. This has been extensively used in the design of the cold crucible inductive melter (CCIM) commissioned in 2010 at La Hague plant. Finally, it is a powerful tool for prospective studies for processes of the future. Whatever the purpose, the potential benefits are gains on the reliability, the output capacity and the life time

Glass-Ceramics in a Cold-Crucible Melter: The Optimum Combination for Greater Waste Processing Efficiency

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%

Advanced concepts for uranium and plutonium multi-recycling

International audienceThe multiple recycling of plutonium and uranium is a main stake to gradually achieve a fully closed nuclear fuel cycle in the future once first Generation IV fast reactors will be deployed into the fleet. To reach this objectives, optimizations of current processes and technologies and, in some cases, development of innovative concepts are required to meet the scientific, technical and economical challenges imposed by the treatment of spent fuels containing increasing Pu content. Based on the significant past experience acquired in France in LWR and FR MOX fuel treatment, RetD studies are in progress at CEA to develop new efficient processes for Pu recycling and for FR MOX fuels fabrication. More compact and economically competitive processes, ensuring the safety/security of the facilities (regarding in particular criticality and proliferation resistance) have to be developed where as plutonium amounts will be one order of magnitude higher than in UOX fuels. New concepts for the head-end operations for MOX dissolution, for the separation of plutonium and uranium by solvent extraction with higher Pu/U ratios, for their conversion into mixed oxides, for MOx fabrication avoiding powder milling, and for optimized management of effluents and waste have been put forward to propose an ambitious program for the 4th generation plants

A method for comprehensive proteomic analysis of human faecal samples to investigate gut dysbiosis in patients with cystic fibrosis

BACKGROUND: This chapter reports the evaluation of two shotgun metaproteomic workflows. The methods were developed to investigate gut dysbiosis via analysis of the faecal microbiota from patients with cystic fibrosis (CF). We aimed to set up an unbiased and effective method to extract the entire proteome, i.e. to extract sufficient bacterial proteins from the faecal samples in combination with a maximum of host proteins giving information on the disease state.; METHODS: Two protocols were compared; the first method involves an enrichment of the bacterial proteins while the second method is a more direct method to generate a whole faecal proteome extract. The different extracts were analysed using denaturing polyacrylamide gel electrophoresis followed by liquid chromatography-tandem mass spectrometry aiming a maximal coverage of the bacterial protein content in faecal samples.; RESULTS AND CONCLUSIONS: In all extracts, microbial proteins are detected, and in addition, nonbacterial proteins are detected in all samples providing information about the host status. Our study demonstrates the huge influence of the used protein extraction method on the obtained result and shows the need for a standardised and appropriate sample preparation for metaproteomic analysis. To address questions on the health status of the patients, a whole protein extract is preferred over a method to enrich the bacterial fraction. In addition, the method of the whole protein fraction is faster, which gives the possibility to analyse more biological replicates