纯钚在辐照条件下相稳定性的热力学研究

[Background] Pu is an important material for nuclear industry, its structure is sensitive to temperature, and irradiation has an important impact on it. [Purpose] In order to explore the thermodynamic effects of irradiation on plutonium, the phase diagram of pure Pu under the irradiation established in this study provides important theoretical guidance for the design of Pu-based nuclear fuels. [Methods] Based on Gibbs free energy of pure Pu, the thermodynamic model of Pu under irradiation was established by considering the excess free energy of vacancies under irradiation conditions. [Results] The Gibbs free energy function under different irradiation was calculated, and the phase diagrams of pure Pu under different irradiation intensities were obtained. The effects of different irradiation conditions and irradiation time on the stability of six allotropic phases were analyzed. [Conclusion] The results indicated that irradiation has great influence on the phase stability of plutonium at lower temperature and the stable phase region of γ-Pu appears near room temperature. Its stable temperature range increased with the increase of the intensity of irradiation and time.