New lead-free chemistry for in-situ monitoring of advanced nuclear power plant

Nuclear power is essential for sustainable energy infrastructure and economic development,necessitating materials for high-radiation environments that can facilitate visualization and observation.Conventional lead glass is inadequate for future requirements due to radiation-induced darkening,poor mechanical properties,and toxicity.Therefore,there is urgent to find new window materials that offer multi-ionization shielding(particularly against deep-penetrating gamma ray,γ,and neutron,n,radiations),desirable opto-mechanical properties,service stability against darkening,and non-toxicity.In this study,we report a family of transparent rare-earth pyrochlore ceramics La_(x)Gd_(2-x)Zr_(2)O_(7),offering unique chemo-physical properties that are ideal for robust radiation shielding windows.Remarkably,we demonstrated the capability of maintaining high transparency under heavy-dose exposure to 1000 kGy ^(60)Coγradiation.We observed the service stability against radiation darkening can be greatly enhanced with La-rich compositions,while Gd-rich compositions undergo shallow darkening that can be reversibly recovered under visible light.This behavior is attributed to mitigated oxygen migration from 48f to 8a in La-rich compositions,which have high pyrochlore phase stability and well-ordered atomic structures,and reversible oxygen migration between 48f and 8a in Gd-rich compositions,which remain active at room temperature.Our proposal and demonstration unlock ample opportunities in designing functional transparent ceramics as window materials for demanding applications in high-radiation environments.