Nuclear waste treatment by induction heating and stirring of a metal/glass bath: the PIVIC process

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Treatment of nuclear mixed waste by induction heating and electromagnetic stirring of a metal/glass bath the PIVIC process.

International audienceA fusion process based on low-frequency induction heating has been developed to treat mixed radioactive waste and produce biphasic glass/metal canisters compatible with a storage in a geological repository. The direct transfer of inductive power to the metal load ensures that fusion occurs directly in the final container and avoids a pouring stage. A thermal equilibrium develops during fusion between the power transmitted by induction and the power evacuated in the furnace's cooling circuits. The generator's electrical parameters are used to determine the amount of metal present in the canister

development of a dosage system for the incineration of radioactive and particle-laden liquid

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Numerical simulation of transitions between back discharge regimes

ACLInternational audienceThis paper presents numerical simulations of transitions between back discharge regimes. Back discharge refers to any discharge initiated at or near a dielectric layer covering a passive electrode. In this work, a pinhole in a dielectric layer on a plane anode serves as a model for back discharge activity. We have studied transitions between back discharge regimes by varying the surface charge density on the dielectric layer and the electric field in front of the pinhole. From the variation of these two independent parameters, the back discharge regimes have been depicted as a mode diagram inspired by the experimental study of Masuda and Mizuno. The resulting diagram includes the different discharge regimes that are commonly observed in experiments. The propagation of a positive ionizing wave inside the pinhole toward its edge, and the resulting formation of a plasma zone at its exit constitute the onset stage of back discharge. From this stage, the transitions to volume discharge or surface discharge can occur. The volume discharge regime consists of the propagation of a discharge in space toward the cathode which can be superimposed with the propagation of a discharge above the dielectric layer surface. The diagram reveals the conditions for transitions between back discharge regimes. © 2014 EDP Sciences

The Elipse Process An underwater plasma technology for hazardous organic liquid treatment

International audienceHazardous liquid organic wastes are very various and produced in different quantities. Some of themare treated through specific processes when others are still waiting from outlet to be destroyed andstabilized. Their different composition (chlorinated, phosphate, sulfated, fluorinated ) make theirtreatment difficult by the same technology.The ELIPSE process has been designed to propose an innovative solution leading to a global treatmentof what is usually called orphan liquids. This brand new technology involved a non-transferredplasma torch working under a water column ensuring the cooling, the filtration and the scrubbing ofthe gases coming from the combustion of the liquids. Furthermore, the water that ensures the globalcooling of the system leads to low or to no corrosion in a compact process. Only the nozzle of the torchmay be affected by the corrosion and may become a wearing part of the treatment system.After giving a detailed description of the ELIPSE process, the present paper will focus on the resultsobtained for the treatment of such different liquids as tributyl phosphate, perfluorinated oil andtrichloroethylene. In addition to obtaining destruction efficiency upper than 99%, the corrosion of thereactor seems to have been significantly limited. These features lead to the first conclusion that theELIPSE process could be a solution for the future to the problem of the hazardous liquid treatment.Furthermore, if the main objective of the ELIPSE process is the destruction of hazardous waste throughinstantaneous combustion in oxygen plasma, their gasification could be envisaged through argonand/or water plasma in order to produce Syngas for energy recovery

An Innovative Technology Using Submerged PlasmaThe ELIPSE Process for Liquid Treatment

International audienceHazardous liquid organic wastes, radioactive or not, are very various and produced in different quantities. Some of them are treated through specific processes when others are still waiting from outlet to be destroyed and stabilized. Their different composition (chlorinated, phosphate, sulfated, fluorinated, …) make their treatment difficult in a same technology. The ELIPSE process has been design to propose an innovative solution leading to a global treatment of what is usually called “orphan liquids”. This brand new technology involved a non-transferred plasma torch working under a water column ensuring the cooling, the filtration and the scrubbing of the gases coming from the combustion of the liquids. Furthermore, the water that ensures the global cooling of the system leads to low or to avoid the corrosion in a compact process. Only the nozzle of the torch may be affected by the corrosion and may become a wearing part of the system of treatment. After giving a detailed description of the ELIPSE process, the present paper will focus on the results obtained for the treatment of such different liquids as tributyl phosphate, perfluorinated oil and trichloroethylene. In addition to obtaining destruction efficiency upper than 99 per cent, the corrosion seems to have been significantly limited. These features lead to the first conclusion that the ELIPSE process could be a solution for the future to the problem of the hazardous liquid treatment

Thermo- and photo- oxidation reaction scheme in a treatment system using submerged plasma

International audienceSome of hazardous liquid organic wastes, radioactive or not, are waiting from outlet to be destroyed. The ELIPSE process is a new technology of organic liquid destruction, involving a thermal plasma working under a water column, which ensures the cooling, the filtration and the scrubbing of the gases coming from the degradation. This study deals with the ability of the ELIPSE process to destroy the pure organic liquids and then to reduce the amount of organic matter remaining in the aqueous solution by means of the thermal or radiative properties of plasma. Preliminary test have shown how efficient the process is for the destruction of the organic liquids when they are directly fed in the plasma hearth. Extensive researches have been performed to assess the ability of the submerged plasma to destroy the remaining organic matters either by reinjecting them with the aqueous solution into the plasma or by using the UV ray coming from the plasma itself. A comparison of the experimental results obtained with various mechanisms proposed by the work carried out highlighted that this UV radiation could, by excitation of water molecules, produce radicals OH which may either dimerise to produce hydrogen peroxide H$_2$O$_2$, or react with organic substances present. The calculation of an activation energy of 8.5 $\pm$ 0.9 kJ mol$^{−1}$ during the experiments shows that these radicals OH$^\circ$ act directly after having been formed which explains a low H$_2$O$_2$ content stability when the solution contains organic compounds. Thus, this photo-oxidation taking place in the water column could be used to improve the destruction of residual organic matter in the solution by maintaining the plasma after processing a given amount of organic liquids

Numerical Simulation of Back Discharge: Influence of Pinhole Geometry on the Regime Transitions

International audienceThis paper presents numerical simulation of back discharge activity that is modelled at a pinhole in a dielectric layer on plane anode. First, for a given pinhole geometry, the transitions between back discharge regimes have been depicted as a mode diagram. Then, we have studied the influence of the dielectric layer thickness on the regime transitions. We have shown that increase in the layer thickness (within range of 0.02\textendash0.2 mm) promotes the back discharge development. Finally, we have studied the influence of `crater configuration'. We have shown that `crater shape' favours the back discharge ignition, whereas limits the resulting discharge development

Flue Gas Treatment by Electrostatic Precipitation

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