RESUMO
In this article, we report the conception and the use of dialysis-based medical device for the extraction of metals. The medical device is obtained by addition in the dialysate of a functionalized chitosan that can chelate endogenous metals like iron or copper. This water-soluble functionalized chitosan is obtained after controlled reacetylation and grafting of DOTAGA. Due to the high mass of chitosan, the polymer cannot cross through the membrane and the metals are trapped in the dialysate during hemodialysis. Copper extraction has been evaluated in vitro using an hemodialysis protocol. Feasibility study has been performed on healthy sheep showing no acute toxicity througout the entire dialysis procedure and first insights of metallic extraction even on healthy animals.
RESUMO
Long term in situ diffusion experiments in the Callovian-Oxfordian mudstone (France) are designed in the context of nuclear waste management. ß-emitters HTO and 36Cl radiotracers are representative of neutral and anionic species in these experiments. Studies have been carried out to design an in situ beta monitoring system in order to quantify tracer migration in the rock pore water over time. The development, design and calibration of ß-emitter radiation sensors were performed. An optimised geometry was calculated for the detection chamber of 36Cl in solution (Ø×L=30×2mm2) via Monte-Carlo N-Particle transport simulation tools. A better SNR (Signal to Noise Ratio) was obtained with YSO cylindrical crystal (Ø×L=6.5×0.5mm2). A sensitivity of 0.21cpm/Bq/mL was measured using 36Cl standards. The 36Cl detection limits were 18Bq/mL and 14.2Bq/mL after 1h and 24h of accumulation time respectively. Such beta sensors, placed 350mm from the radiotracer injection borehole, could successfully discriminate 36Cl anisotropic diffusion in various directions within 4 years. It will be tested in situ and can be adapted to other in situ experience.