Development of Vitrification Process and Glass Formulation for Nuclear Waste Conditioning

The vitrification of high-level waste is the internationally recognized standard to minimize the impact to the environment resulting from waste disposal as well as to minimize the volume of conditioned waste to be disposed of. COGEMA has been vitrifying high-level waste industrially for over 20 years and is currently operating three commercial vitrification facilities based on a hot metal crucible technology, with outstanding records of safety, reliability and product quality. To further increase the performance of vitrification facilities, CEA and COGEMA have been developing the cold crucible melter technology since the beginning of the 1980s. This type of melter is characterized by a virtually unlimited equipment service life and a great flexibility in dealing with various types of waste and allowing development of high temperature matrices. In complement of and in parallel with the vitrification process, a glass formulation methodology has been developed by the CEA in order to tailor matrices for the wastes to be conditioned while providing the best adaptation to the processing technology. The development of a glass formulation is a trade-off between material properties and qualities, technical feasibility, and disposal safety criteria. It involves non-radioactive and radioactive laboratories in order to achieve a comprehensive matrix qualification. Several glasses and glass ceramics have thus been studied by the CEA to be compliant with industrial needs and waste characteristics: glasses or other matrices for a large spectrum of fission products, or for high contents of specifics elements such as sodium, phosphate, iron, molybdenum, or actinides. New glasses or glass-ceramics designed to minimize the final wasteform volume for solutions produced during the reprocessing of high burnup fuels or to treat legacy wastes are now under development and take benefit from the latest CEA hot-laboratories and technology development. The paper presents the CEA state-of-the-art in developing matrices or glasses and provides several examples

DNA-PK Is Targeted by Multiple Vaccinia Virus Proteins to Inhibit DNA Sensing

Virus infection is sensed by pattern recognition receptors (PRRs) detecting virus nucleic acids and initiating an innate immune response. DNA-dependent protein kinase (DNA-PK) is a PRR that binds cytosolic DNA and is antagonized by vaccinia virus (VACV) protein C16. Here, VACV protein C4 is also shown to antagonize DNA-PK by binding to Ku and blocking Ku binding to DNA, leading to a reduced production of cytokines and chemokines in vivo and a diminished recruitment of inflammatory cells. C4 and C16 share redundancy in that a double deletion virus has reduced virulence not seen with single deletion viruses following intradermal infection. However, non-redundant functions exist because both single deletion viruses display attenuated virulence compared to wild-type VACV after intranasal infection. It is notable that VACV expresses two proteins to antagonize DNA-PK, but it is not known to target other DNA sensors, emphasizing the importance of this PRR in the response to infection in vivo

Nuclear Liquid Wastes Calcination: The High-Level French Experience – 17184

International audienceCalcination is an efficient process for volume reduction and stabilization of nuclear liquid wastes. It is often the first step of waste containment processes such as vitrification or grouting.The CEA (French Alternative Energies and Atomic Energy Commission) and AREVA have acquired a high-level experience in the field of calcination through more than forty years of R&D and industrial operation. During this period, a broad range of liquid wastes have been studied and treated.R&D work and associated engineering studies allowed defining the design and sizing of the equipment and the process control parameters to be applied for the calcination of all kinds of solutions.The calcination process has been qualified for the following effluents amongst others:Liquid waste from UOx fuel reprocessingLiquid waste from UMo fuel reprocessing (high molybdenum and phosphorus contents)Hanford HLWLiquid waste from D&D operation (sodium bearing waste)This paper presents several studies led by the Joint Vitrification Laboratory (L.C.V), a common research laboratory between CEA and AREVA in charge of qualifying new processes and matrices for waste containment. These studies allowed defining the calcination rules, in particular for very hard to process solutions such as effluents with high boron, molybdenum and sodium contents.The feedback from industrial operation of the calcination process with fission products and effluents from D&D operations, highly loaded with sodium, is also presented

Vaccinia virus evasion of regulated cell death

Regulated cell death is a powerful anti-viral mechanism capable of aborting the virus replicative cycle and alerting neighbouring cells to the threat of infection. The biological importance of regulated cell death is illustrated by the rich repertoire of host signalling cascades causing cell death and by the multiple strategies exhibited by viruses to block death signal transduction and preserve cell viability. Vaccinia virus (VACV), a poxvirus and the vaccine used to eradicate smallpox, encodes multiple proteins that interfere with apoptotic, necroptotic and pyroptotic signalling. Here the current knowledge on cell death pathways and how VACV proteins interact with them is reviewed. Studying the mechanisms evolved by VACV to counteract host programmed cell death has implications for its successful use as a vector for vaccination and as an oncolytic agent against cancer.Work in C.M.d.M. laboratory is supported by grants from the Biotechnology and Biological Sciences Research Council (BB/M003647/1) and the Medical Research Council (MR/M011607/1). Work in G.L.S. laboratory is supported by grants from the MRC and Wellcome Trust. G.L.S. is a Wellcome Trust Principal Research Fellow

Vaccinia virus inhibits NF-κB-dependent gene expression downstream of p65 translocation

The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcription factor plays a critical role in host defence against viral infection by inducing the production of pro-inflammatory mediators and type I interferon. Consequently, viruses have evolved many mechanisms to block its activation. The poxvirus vaccinia virus (VACV) encodes numerous inhibitors of NF-κB activation that target multiple points in the signaling pathway. A derivative of VACV strain Copenhagen, called vv811, lacking 55 open reading frames in the left and right terminal regions of the genome, was reported to still inhibit NF-κB activation downstream of tumour necrosis factor (TNF)α and interleukin (IL)-1β, suggesting the presence of one or more additional inhibitors. In this study we constructed a recombinant vv811 lacking the recently described NF-κB inhibitor A49 (vv811ΔA49), yielding a virus that lacked all currently described inhibitors downstream of TNFα/IL-1β. Unlike vv811, vv811ΔA49 no longer inhibited degradation of phosphorylated IκBα and p65 translocated into the nucleus. However, despite this translocation, vv811ΔA49 still inhibited TNFα- and IL1β-induced NF-κB-dependent reporter gene expression and the transcription and production of cytokines induced by these agonists. This inhibition did not require late viral gene expression. These findings indicate the presence of another inhibitor of NF-κB that is expressed early during infection and acts by a novel mechanism downstream of p65 translocation into the nucleus

Vaccinia virus inhibits NF-κB-dependent gene expression downstream of p65 translocation

The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcription factor plays a critical role in host defence against viral infection by inducing the production of pro-inflammatory mediators and type I interferon. Consequently, viruses have evolved many mechanisms to block its activation. The poxvirus vaccinia virus (VACV) encodes numerous inhibitors of NF-κB activation that target multiple points in the signaling pathway. A derivative of VACV strain Copenhagen, called vv811, lacking 55 open reading frames in the left and right terminal regions of the genome, was reported to still inhibit NF-κB activation downstream of tumour necrosis factor (TNF)α and interleukin (IL)-1β, suggesting the presence of one or more additional inhibitors. In this study we constructed a recombinant vv811 lacking the recently described NF-κB inhibitor A49 (vv811ΔA49), yielding a virus that lacked all currently described inhibitors downstream of TNFα/IL-1β. Unlike vv811, vv811ΔA49 no longer inhibited degradation of phosphorylated IκBα and p65 translocated into the nucleus. However, despite this translocation, vv811ΔA49 still inhibited TNFα- and IL1β-induced NF-κB-dependent reporter gene expression and the transcription and production of cytokines induced by these agonists. This inhibition did not require late viral gene expression. These findings indicate the presence of another inhibitor of NF-κB that is expressed early during infection and acts by a novel mechanism downstream of p65 translocation into the nucleus

Analysis of the anti-apoptotic activity of four vaccinia virus proteins demonstrates that B13 is the most potent inhibitor in isolation and during viral infection.

Vaccinia virus (VACV) is a large dsDNA virus encoding ~200 proteins, several of which inhibit apoptosis. Here, a comparative study of anti-apoptotic proteins N1, F1, B13 and Golgi anti-apoptotic protein (GAAP) in isolation and during viral infection is presented. VACVs strains engineered to lack each gene separately still blocked apoptosis to some degree because of functional redundancy provided by the other anti-apoptotic proteins. To overcome this redundancy, we inserted each gene separately into a VACV strain (vv811) that lacked all these anti-apoptotic proteins and that induced apoptosis efficiently during infection. Each protein was also expressed in cells using lentivirus vectors. In isolation, each VACV protein showed anti-apoptotic activity in response to specific stimuli, as measured by immunoblotting for cleaved poly(ADP ribose) polymerase-1 and caspase-3 activation. Of the proteins tested, B13 was the most potent inhibitor, blocking both intrinsic and extrinsic stimuli, whilst the activity of the other proteins was largely restricted to inhibition of intrinsic stimuli. In addition, B13 and F1 were effective blockers of apoptosis induced by vv811 infection. Finally, whilst differences in induction of apoptosis were barely detectable during infection with VACV strain Western Reserve compared with derivative viruses lacking individual anti-apoptotic genes, several of these proteins reduced activation of caspase-3 during infection by vv811 strains expressing these proteins. These results illustrated that vv811 was a useful tool to determine the role of VACV proteins during infection and that whilst all of these proteins have some anti-apoptotic activity, B13 was the most potent

Analysis of the anti-apoptotic activity of four vaccinia virus proteins demonstrates that B13 is the most potent inhibitor in isolation and during viral infection.

Vaccinia virus (VACV) is a large dsDNA virus encoding ~200 proteins, several of which inhibit apoptosis. Here, a comparative study of anti-apoptotic proteins N1, F1, B13 and Golgi anti-apoptotic protein (GAAP) in isolation and during viral infection is presented. VACVs strains engineered to lack each gene separately still blocked apoptosis to some degree because of functional redundancy provided by the other anti-apoptotic proteins. To overcome this redundancy, we inserted each gene separately into a VACV strain (vv811) that lacked all these anti-apoptotic proteins and that induced apoptosis efficiently during infection. Each protein was also expressed in cells using lentivirus vectors. In isolation, each VACV protein showed anti-apoptotic activity in response to specific stimuli, as measured by immunoblotting for cleaved poly(ADP ribose) polymerase-1 and caspase-3 activation. Of the proteins tested, B13 was the most potent inhibitor, blocking both intrinsic and extrinsic stimuli, whilst the activity of the other proteins was largely restricted to inhibition of intrinsic stimuli. In addition, B13 and F1 were effective blockers of apoptosis induced by vv811 infection. Finally, whilst differences in induction of apoptosis were barely detectable during infection with VACV strain Western Reserve compared with derivative viruses lacking individual anti-apoptotic genes, several of these proteins reduced activation of caspase-3 during infection by vv811 strains expressing these proteins. These results illustrated that vv811 was a useful tool to determine the role of VACV proteins during infection and that whilst all of these proteins have some anti-apoptotic activity, B13 was the most potent

A methodology for evaluating the performance of software, using gamma spectrometry, for determining the isotopic composition of plutonium

International audienceThis paper presents the progress of an ongoing study within Working Group N°27 of the CETAMA[1] regarding the performances of software used for determining the isotopic composition of plutonium and uranium, by means of γ spectrometry, in the presence of “disturbing” radioactive emitters and of various matrices. The “disturbing” radio-emitters are some minor actinides (242Am, 243Am, 237Np, 243Cm etc.), fission products (137Cs, 125Sb, 154Eu etc.) and/or activation products (60Co etc.). All these radionuclides can be found in waste from the nuclear industry. Matrices can also vary (metal, vinyl…). In some instances, these radionuclides and matrices are in high enough quantities to disturb the analysis by the software for determining the isotopic composition. This paper presents the outline and first achievements of this. [1] The CETAMA (Commission d'Etablissement des Méthodes d'Analyse), part of the CEA, has served laboratories for analysis and monitoring facilities throughout the French nuclear sector. Working group N°27 brings together experts in neutron and gamma spectrometry measurements to identify suitable non destructive assay methods for waste packages of all shapes, all backgrounds and all levels of alpha or beta-gamma emitters

UMo solutions processing in La Hague Cold Crucible Induction Melter the feedbackfrom the first years of operation

International audience250 cubic meters of high-level liquid waste from reprocessed U-Mo-Sn-Al spent fuel, used in GasCooled Reactors (GCR), were produced during the mid-1960s at La Hague facility. These UMo solutions are less radioactive than the current fission product concentrates coming from ongoingreprocessing activities, but are very rich in molybdenum and phosphorus whose contents make themolten glass quite corrosive and require a high-temperature glass formulation to obtain sufficientlyhigh waste loading factors (12 percent in molybdenum oxide). Hence the use of the Cold Crucible InductionMelter (CCIM) technology to process such solutions has been deemed a good opportunity for AREVAto meet its performance expectations.In addition to being very corrosive, the UMo waste is quite challenging to process as the molybdenumhas a strong tendency to stick in the calciner and causes clogging issues in off-gas treatmentequipment. Therefore, the process and technological qualifications were deployed in order to addressthese specific issues.UMo solutions processing in the La Hague CCIM has started in January 2013 and is currentlyongoing. During this period (from 2013 to 2015), many data have been collected to confirm theprocess parameters that were defined during the qualification of this innovating process. Even if somedifficulties occurred, operations teams experience along with engineering and RandD support allowedmanaging them.This paper presents the start-up methodology and the feedback from the first years of UMo solutionsprocessing with the CCIM technology at La Hague site. Lessons learned are presented with thedifficulties encountered and the solutions implemented, emphasizing the benefits of a close integrationbetween RandD, engineering and operations teams