NiFe2O4 is a key component of CRUD (corrosion-related undesirable deposits) that may severely degrade the safety and efficiency of nuclear power systems. Recent experimental studies showed that Cr impurity may affect the formation and growth of NiFe2O4-rich deposit on Cr-coated nuclear fuel, demonstrating a promising solution to inhibit the growth of CRUD. However, little theoretical study has been dedicated to revealing the effect of impurity on the formation and growth of NiFe2O4, especially Cr. In this work, density functional theory was utilized to compute the effect of Cr doping on electronic structures of NiFe2O4. The calculation results suggested that the effect of Cr impurity on NiFe2O4 structural stability is site-dependent and provides theoretical evidence that explains the experimental observation of suppressed NiFe2O4-rich CRUD growth on Cr-coated nuclear fuel. We believe that lattice mismatch induced by Cr doping may lead to stress and dislocations, which suppressed further growth of NiFe2O4. Subsequently, the diffusion of Cr facilitates the smooth growth of the interface, suggesting that the diffusion of Cr may be a crucial factor influencing the growth rate of CRUD.

Adding plasmonic nanostructures to perovskite solar cells (PSCs) can boost light absorption, but often at the cost of new electronic losses. Based on 3D FDTD simulations, this study demonstrates how Au@Al₂O₃ core-shell nanostructures can overcome this fundamental trade-off through a dual function of the Al₂O₃ shell, namely its moderate refractive index and excellent passivating properties. In addition, the geometry of Au@Al₂O₃ core–shell nanostructure is optimized to produce a maximum short-circuit current density ($J_{sc}$) of 25 mA cm⁻². The simulations provide mechanism-level design rules that link dielectric choice and geometry to near-field localization and far-field coupling in perovskite absorbers. An experimentally testable parameter window is reported rather than device-level performance claims, with explicit discussion of energy partitioning and stability caveats associated with plasmonic loss in Au and interfacial chemistry.

Uranium mononitride (UN) is a promising nuclear fuel with a high melting point, high thermal conductivity, and low coefficient of thermal expansion. Theoretical studies of UN can provide insights on its thermal transport mechanism, which is of great significance for the design and application of UN fuel. During the processing and operation, crystal defects and impurities, such as vacancies and carbon impurities, potentially arise in the nuclear fuel, which probably affect the thermomechanical properties of UN. To figure out the effect of vacancy defects and carbon impurities on the thermal conductivity of UN, density functional theory and Boltzmann transport theory are applied to conduct a theoretical investigation on the mechanical and thermal properties of ideal and defective UN. The calculated results show that in the case of UN with a U or N vacancy, both the lattice and electronic thermal conductivity are decreased, compared with the ideal case. With a carbon atom occupying the N site in the lattice, the electronic thermal conductivity is reduced but the lattice thermal conductivity is increased. Combining the results of lattice and electronic thermal conductivity, the total thermal conductivities of three defective states are lower than the ideal UN. The thermal conductivities of UN with a U vacancy (13.91 W/mK), N vacancy (15.36 W/mK), and a carbon atom occupying the N site (15.14 W/mK) are, respectively, reduced by 25.7%, 18.0%, and 19.2%, in comparison with ideal result (18.73 W/mK) at 1000 K.