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Abstract: The influence of high burn-up structured material on UO2 corrosion has been studied in an autoclave experiment. The experiment was conducted on spent fuel fragments with an average burn-up of 67GWd/tHM. They were corroded in a simplified groundwater containing 33mM dissolved H2 for 502days. All redox sensitive elements were reduced. The reduction continued until a steady-state concentration was reached in the leachate for U at 1.5×10−10 M and for Pu at 7×10−11 M. The instant release of Cs during the first 7days was determined to 3.4% of the total inventory. However, the Cs release stopped after release of 3.5%. It was shown that the high burn-up structure did not enhance fuel corrosion. [Copyright &y& Elsevier]

To reduce uncertainties in determining the source term and evolving condition of spent nuclear fuel is fundamental to the safety assessment. ß-emitting nuclides pose a challenging task for reliable, quantitative determination because both radiometric and mass spectrometric methodologies require prior chemical purification for the removal of interfering activity and isobars, respectively. A method for the determination of 90 Sr at trace levels in nuclear spent fuel leachate samples without sophisticated and time-consuming procedures has been established. The analytical approach uses a commercially available automated pre-concentration device (SeaFAST) coupled to an ICP-DRC-MS. The method shows good performances with regard to reproducibility, precision, and LOD reducing the total time of analysis for each sample to 12.5 min. The comparison between the developed method and the classical radiochemical method shows a good agreement when taking into account the associated uncertainties.

Accurate analytical data reinforces fundamentally the meaningfulness of nuclear fuel performance assessments and nuclear waste characterization. Regularly lacking matrix-matched certified reference materials, quality assurance of elemental and isotopic analysis of nuclear materials remains a challenging endeavour. In this context, this review highlights various dedicated experimental approaches envisaged at the European Commission-Joint Research Centre-Institute for Transuranium Elements to overcome this limitation, mainly focussing on the use of high resolution-inductively coupled plasma-optical emission spectrometry (HR-ICP-OES) and sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). However, also α- and γ-spectrometry are included here to help characterise extensively the investigated actinide solutions for their actual concentration, potential impurities and isotopic purity.

Reliable knowledge of the (79)Se half-life is crucial, e.g. for the safety assessments of final repositories for nuclear waste. However, a literature survey reveals an inconsistent picture, indicating remarkably difficult experimental conditions. This work reports a new value of 3.27(8) × 10(5) a for the half-life of (79)Se. The uncertainty is less than half of the latest published result. The sample was prepared radiochemically pure from a reprocessing solution by exploitation of reductive deposition on Cu, anion exchange chromatography and sublimation. The specific activity was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and liquid scintillation counting (LSC). Hydride generation multicollector inductively coupled plasma mass spectrometry (HG-MC-ICP-MS) was applied for the establishment of the isotopic composition., (Copyright 2010 Elsevier Ltd. All rights reserved.)