Analyse d'eaux radioactives d'un condenseur de réacteur nucléaire par spectrométrie de fluorescence X à réflexion totale (TXRF), dans un laboratoire en zone surveillée sans protection biologique

Total-Reflexion X-Ray Fluorescence Spectrometry differs fundamentally from classical X-ray fluorescence (XRF). The differences between XRF and TXRF apply to sample preparation, calibration, data analysis and detection performance as well as to the objects under investigation. Instrumental detection limits is a few pg for most of elements (Z>13). Besides the high detection power, internal standardization is another important feature, providing a simple and reliable quantification of a multi-elementary analysis. In addition, the small sample mass required enables micro-analytical questions to be tackled. The analysis of a radioactive water can be considered as micro-analysis. Addition of internal standard, dilution and deposit can be done in nuclear laboratories. After evaporation, the activity must be inferior to 7000 Bq for alpha emitters, 107 Bq for beta gamma emitters and the measurement can be done in non controlled zones. The results can be compared with the same analysis done with ICP/MS in glove box

Role of microstructure and heat treatments on the desorption kinetics of tritium from austenitic stainless steels

Communication par affich

Role of microstructure and heat treatments on the desorption kinetics of tritium from austenitic stainless steels.

International audienceThe liquid scintillation counting of solid samples (LSC-SS technique) was successfully used to study the role of microstructure and heat treatments on the behavior of residual tritium in several austenitic stainless steels (as-cast remelted tritiated waste, 316LN and 321 steels). The role of desorption annealing in the 100-600 degrees C range on the residual amount of tritium in tritiated waste was investigated. The residual tritium concentration computed from surface activity measurements is in good agreement with experimental values measured by liquid scintillation counting after full dissolution of the samples. The kinetics of tritium desorption recorded with the LSGSS technique shows a significant desorption of residual tritium at room temperature, a strong barrier effect of thermal oxide films on the tritium desorption and a dependance of the tritium release on the steels microstructure. Annealing in the 300-600 degrees C range allows to desorb a large fraction of the residual tritium. However a significant trapping of tritium is evidenced. The influence of trapping phenomena oil the concentration of residual tritium and on its dependance with the annealing temperature was investigated with different recrystallized and sensitized micro structures. Trapping is evidenced mainly below 150 degrees C and concerns a small fraction of the total amount of tritium introduced in austenitic steels. It presumably occurs preferentially on precipitates such as Ti(CN) or on intermetallic phases

Influence of heat treatments on residual tritium amount in tritiated stainless steels waste

International audienc

Impurities and oxygen control in lead alloys

International audienceThe control of the impurities is of major interest for ensuring adequate and safe operation of lead alloys facilities from the viewpoint of the corrosion phenomenon. Specific methods have to be implemented for effective control of the liquid lead–bismuth eutectic quality to the required specifications, as for instance: dissolved oxygen monitoring, dip sampling system, analytical techniques for impurities measurement. Even though the oxygen control in the static facility BIP proved difficult, a better knowledge of kinetics behaviour of the oxygen is acquired. Oxygen sensors gave results in agreement with the theory during the tests achieved on the BIP and on the COLIMESTA facilities. The dip sampler was validated on static device: it allows an effective sampling of the liquid metal melt and an easy separation of the melt from the sampling device when cold. The set of analytical techniques for the measurements of metallic impurities is efficient as well, except for the nickel element, for which the method of analysis with atomic absorption spectroscopy coupled with spiking method should allow the lower detection limit to be decreased below the 5 $\mu$g/g as for the iron impurity