Temperature profiles in UO2 fuel under direct electric heating conditions

The thermal environment of UO₂ fuel in reactor may be simulated under conditions of direct electric heating (DEH). Using reasonable assumptions, the complex thermal/electrical system is modeled mathematically by the DEHSSTD code. The algorithm computes the thermal and linear power profiles in the fuel and in addition a history dependent scale factor for the thermal conductivity and for the electrical conductivity. These account for the dependence of materials properties on the physical state of the fuel. The DEHSSTD model is applicable under both steady-state and transient conditions. Convergence of the DEHSSTD model is studied and optimization performed for the model's fuel parameters. DEH and reactor thermal environments are compared, the DEH temperature profile being more sharply peaked at the fuel's center. An equivalent nuclear power is defined on the basis of the DEH temperature distribution.