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International audience; In the scope of fast reactor spent fuel recycling, head-end research and development are performed at the Atalante facility in Marcoule. Considering the initial plutonium content, quantitative plutonium recovery is one of the main objectives for the dissolution process. In addition, the quantities of undissolved residue increase with the burn up and can impact the waste conditioning downstream. A silver (II) oxidizing digestion step was studied to assess its application to the treatment of undissolved residues containing eventually some plutonium. This process was first optimised on dioxide plutonium powders, and then tested on irradiated LWR MOX fuel residues. More recently it was applied to the solid residue obtained after dissolving in nitric media a MOX fuel irradiated in the Phenix Sodium Fast Reactor (SFR). In light of past experimentations and in order to obtain new basic data, not the whole spin was dissolved but only separate sections linked to known local burn-ups (BU). The first objective was to better correlate the quantity/composition of the dissolution residues with the local BU and Pu content of the initial irradiated material. Then the digestion step was applied on each dissolution residue obtained from each fuel pin part (bottom, medium i.e. full-flux zone, upper) with a view to evaluating the complementary Pu recovery, studying key parameters and characterising secondary residues.The digestion step permitted to recover up to 99% of residual plutonium with some slight differences depending on the position of the pin part the dissolution residue was obtained from. Oxidation conditions, local burn-up and chemical composition were found to be influential. Quantity of residues after digestion was significantly reduced thanks to this digestion treatment. The ultimate residues consisted mainly of metallic compound like ruthenium, molybdenum, rhodium or palladium.

International audience; Given the initial plutonium content in SFR MOX fuel, its quantitative recovery is one of the main objectives for the dissolution process. A silver (II) oxidative digestion step was studied in the Atalante facility to assess its possible application to the treatment of undissolved residues obtained after dissolving spent SFR MOX fuel in nitric acid. This process was first optimized on plutonium dioxide powders, and then tested on irradiated LWR MOX fuel residues. The digestion step permitted the recovery of up to 99% of the residual plutonium, with some slight differences depending on the position of the pin part from which the dissolution residue was obtained. Local burnup and chemical composition were found to be influential. The quantity of residues after digestion was significantly reduced by this treatment, with the final residues consisting mainly of metallic compounds including ruthenium, molybdenum, rhodium or palladium.

magnetization transfer imaging (MT) has been used to study the degree of demyelination in progressive multifocal leukoencephalopathy (PML).two groups were studied: a group of 10 HIV + patients with clinical, MR features, biological and/or biopsy proven PML, and a group of 11 normal volunteers with matched age. MT ratio (MTR) were obtained from the center of the PML lesions and 11 areas of normal appearing white matter (NAWM) in the control group.the mean MTR of NAWM in the control group was 46.6% (SD = 2,3). PML lesions demonstrated a strong and significant (p = 0) decreased of the MTR with mean MTR value of 22.4% (SD = 2,3).MT characterized the demyelinating process in PML, and can be used to improve diagnosis. Furthermore, MT allowed a quantification of the degree of demyelination which can be helpful in other demyelinating process of CNS such as multiple sclerosis.

Print copy held at NRC. Digital version available upon request. Contact NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca, Copie papier conservée au CNRC. Version numérique disponible sur demande. Contactez NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca

Print copy held at NRC. Digital version available upon request. Contact NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca, Copie papier conservée au CNRC. Version numérique disponible sur demande. Contactez NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca

Print copy held at NRC. Digital version available upon request. Contact NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca, Copie papier conservée au CNRC. Version numérique disponible sur demande. Contactez NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca

Print copy held at NRC. Digital version available upon request. Contact NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca, Copie papier conservée au CNRC. Version numérique disponible sur demande. Contactez NRC.NSL-BSN.CNRC@nrc-cnrc.gc.ca

MT makes it possible to characterize tissue destruction in several CNS diseases, including AIDS-related diseases such as PML or HIV encephalitis. MR may be helpful in establishing diagnosis, disease burden, prognosis, and therapeutic efficacy. MT may also contribute to the investigation of the natural history of the diseases. The other application is in improving contrast after the injection of gadolinium chelates. This contrast improvement can be achieved routinely on any device and may be a good alternative to other methods, such as increasing dose or delay.

We report a case of agenesis of the internal carotid artery which was revealed by a subarachnoid hemorrhage. Angiography showed a ruptured aneurysm of the anterior communicating artery and unilateral absence of the left internal carotid artery. Both the left anterior and middle cerebral arteries were perfused from the right carotid artery via the anterior communicating artery. Absence of the left carotid canal was proved on bone CT. Such an association is discussed. An hemodynamic stress on a congenital defect of the cerebral arterial wall could be the origin of the aneurysm development.