Spectroscopic insights on defects in self-irradiated natural Zircon: A natural analogue for slag host matrix for Zr-metallic wasteform

Abstract

Zircon is a proposed slag host matrix associated with the metallic wasteform route developed for Zr-hull management. This study de-alienates the nature of radiation damage in Zr- and Si- sublattice in self-irradiated zircon matrices under long term of geological times using a natural analogue approach. To address this, self-irradiated reddish-brown zircon from Tamil Nadu, India was characterized using spectroscopic techniques such as X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and Photoluminescence (PL) combined with Monte Carlo Based SRIM calculations. The observations revealed that the “as-received” zircon showed significant radiation damage primarily in the Si-sublattice (Si-O-Si linkages) while retaining its crystallinity, indicating a high degree of radiation resistance. The accumulated alpha-dose and displacements per atom (dpa) were evaluated to be 0.59 × 1018 decays/g and 0.019, respectively using RAMAN and SRIM calculations. Photoluminescence studies reveal that after annealing at 1673 K for 96 h, there was a partial recovery of radiation defects and a decrease in Si-O-Si bonds, although defects from dopant atoms remained unchanged. The damage observed is correlated with the nature of atomic bonding in Si-O and Zr-O bonds. The conclusions drawn suggest that zircon demonstrates considerable durability and selective recovery from radiation damage, making it a promising candidate for radioactive waste management.