Résumé
The confinement of high-level radioactive waste from spent nuclear fuel reprocessing is a key point in the nuclear cycle. In France, waste storage is based on three containment barriers including a glass package (within its primary canister, a stainless steel container), a thick carbon steel overpack and finally a host rock. In this context, a lot of studies are carried out on nuclear glass in order to increase the amount of incorporation of radionuclides inside the glass. The development of such glasses needs some analytical tools as ICP, XRF for global quantification and EPMA for local quantification of the elemental composition.The interest of EPMA on nuclear glass is: to quantify simultaneously many elements (from light elements up to U), to quantify secondary phases in multiphase samples, to allow low detection levels for trace elements quantification. The aim of the present study is to improve the quantification of boron in glass containing molybdenum in order to understand and determine the solubility limit of MoO3 linked to it incorporation capability of the confinement glass material. The main difficulty of the quantification of boron is mainly due to a peak interference between Bka (0.185 keV) and MoMZ (0.193 keV).This study is based on a simplified glass composition such as SiO2-B2O3-Na2O-MoO3 with various molybdenum oxide amounts (from 0 to 11 wt %). The analytical set up was optimized to minimize the measurement uncertainties due to: the sodium migration under electronic beam the Mo/B peak interference (taking into account the boron spectrum shift in an oxide environment). This work allows that molybdenum oxide relative amount can't be superior to 8 wt% (Beyond this limit the interference is not treatable) and Mo solubility limit in such a glass is 3.7 wt%.