Radiation effects in phosphate-based matrices for back-end nuclear applications

MgKPO₄·6H₂O (magnesium potassium phosphate-based cement; MKP) is an environment friendly alternative to Portland cement with potential applications in environmental remediation and radioactive nuclear waste management, particularly in the context of β-emitting Cs and Sr immobilizations. Thus, investigation of the radiation effects and temperature due to decay heat in such material is of prime importance. In this study, MgKPO₄·6H₂O powders were synthesized and subsequently annealed at 1273 K for 2 h under ambient atmosphere to form MgKPO₄. The synthesized and annealed MKP specimens were irradiated under ambient conditions with 10-MeV electron beam up to imparted doses of 20 MGy. XRD results reveal the formation of amorphous fraction in irradiated MgKPO₄·6H₂O, while the annealed MKP specimens exhibit good radiation stability without amorphization. The annealed specimens also indicated good thermal stability when compared to as-prepared MgKPO₄·6H₂O specimen both in pristine and irradiated conditions. Vibrational spectroscopic results confirm that the radiation effect resulted in distortion/removal of structural water and formation of radiolysis products in MgKPO₄·6H₂O.