The objective is to investigate the effects of the insoluble dissolution fines remaining from the Purex process for nuclear fuel reprocessing in the French R7T7 fission product containment glass, with particular attention to the platinoid elements (ruthenium, rhodium and palladium) which are insoluble in the glass and which high activity levels could result in local hot spots.
Insoluble particles, known as fines, present in fission product solutions consist of cladding fragments or undissolved fission products, notably platinoids. Platinoids are found in soluble form with other particles. Regardless of their initial state, the platinoid elements ruthenium, rhodium and palladium are insoluble in the glass. As a result, the amorphous glass mass contains heterogeneous inclusions comprising notably highly radioactive ruthenium and rhodium with substantial thermal power. It is therefore necessary to ascertain whether the reference glass composition is a suitable containment matrix for these active insoluble dissolution fines. The experimental programme will include the fabrication and characterization of glass rods containing actual active fines. A glass composition designated A130 was produced, containing actual fines from dissolution of fuel irradiated in the Advanced Prototype Boiler (CAP) at Cadarache.
The homogeneity of the distribution of five radionuclides was assessed by gamma indicates a relatively uniform distribution. The chemical composition of the glass matrix and the elements or oxides contained was determined in 2 steps: complete dissolution of the glass, followed by ICP analysis and radiometry.
Development of an analysis method for glass containing dissolution fines.
Development of a non-destructive gamma-scanning method to measure the radionuclide distribution and the true activity.
Fabrication of glass rods containing actual active fines; quantification of the fines, and notably the platinoids, in the glass.
Preparation of test specimens after gamma scanning.
Measurement of glass containment properties at room temperature and at 90 C; determination of glass alterability at 90 C.
Leaching of test specimens at 100 C in Soxhlet devices.
Characterization of glass microhomogeneity.