CHARACTERIZATION OF LOW-ACTIVITY AND MEDIUM-ACTIVITY RADIOACTIVE-WASTE

In France specifications for long-lived isotopes, which are critical f or the safety of intermediate storage and disposal on surface sites, h ave been fixed. Because a number of these nuclides are pure beta or al pha emitters, a reliable radiochemical inventory of these isotopes req uires a rather sophisticated preparative chemistry before radiation me asurement. In view of the initial complexity of matrices for various t ypes of waste, the preparation steps constitute a technological limit to the characterization. Therefore, practices eventually developed for synthetic waste may prove insufficient when applied to real samples. For isotopes with half-lives >10(5) yr, such as Tc-99 and I-129, a phy sicochemical technique, inductively coupled plasma/mass spectrometry, constitutes an attractive alternative to radiochemical procedures. How ever, the request for high performance and limitations in sample activ ity does not allow preparative treatments and chemical separations fro m interfering species to be minimized.