Dosage des radionucléides à vie longue 79Se et 126Sn dans les solutions de produits de fission issues du traitement des combustibles nucléaires

The quantification of radionuclides present in waste resulting from the nuclear fuel reprocessing is essential to ensure an optimal management of this waste. This thesis deals with the development of analytical methods for the determination of two long-lived radionuclides: 79Se and 126Sn, in a solution of fission products (FP) exit from nuclear fuel reprocessing. Their determination, by radiochemical method or mass spectrometry, involves selective chemical separations from the others β/γ emitters and from the interfering elements. For 79 Se, a β emitter with a half-life estimated to 10 power 6 years, two techniques , i. E. Precipitation by potassium iodine and separation on ion exchange resins were applied to a solution of FP at COGEMA La Hague. The results showed that only the ion exchange method allows us to obtain a solution sufficiently decontaminated with a significant selenium yield. This separation allows the measurement of the 79Se by electrothermal vaporisation coupled with inductively coupled plasma mass spectrometry. . .