Quantification of low Z elements in sodium borosilicate glass spiked with phosphorous by external (in air) PIGE method: a complementary method to activation analysis

High level-liquid waste (HLW) originating from reprocessing of spent nuclear fuel is immobilized in borosilicate glass matrix. Certain constituents of HLW like Cr or Mo exhibit poor solubility in this glass matrix. Cr is a corrosion product present in HLW that shows solubility of merely 2mol% in borosilicate glass. Generally, glass preparation is being carried out at very high temperature (~1000°C), such high temperature causes the volatilization losses. Hence, the chemical characterization of these borosilicate glass matrixes is very much important. In view of that the Borosilicate glass matrix was prepared by addition of 5 mol% P₂O₅ and solubility of Cr/Mo radionuclides was increased to 4 mol% in modified glass matrix. Quantification of B, Si and P is difficult with the neutron activation analysis. PIGE method is complementary to INAA and capable of simultaneous estimating of low Z elements including neutron poison (B) and Si, Na, Al and P. In present study, in situ current normalized External PIGE method was utilized to ascertain the composition of the modified glass matrix. In this PIGE method, samples were irradiated with the proton beam (I~10-15nA) in the form of pellet. Fluorine was externally added as current normalizer in the sample and standard to monitor the current fluctuation, if any, during the irradiation. Radioactive assay was carried out using HPGe detector