An investigation of the temperature correlation effect in lattice calculations

We are investigating the accuracy of various techniques for representing the temperature profile inside a fuel pin. The simplest approach consists to replace the temperature profile by a single effective temperature. Here, we propose to treat explicitly the temperature gradient in fuel pins, using a subgroup self-shielding model together with various representations of the temperature correlation effect between different isotopes and fuel regions. We conclude that it is now possible to use an explicit representation of the temperature distribution in routine lattice calculations, without the introduction of an effective temperature. (authors)