Validation progress on polaris code for CANDU lattice physics

Polaris is a recent lattice physics code included in the SCALE package for light water reactor (LWR) analysis. Current efforts include adding support for other reactor systems; this project is involved in the addition of support for CANDU reactor modelling. Code was added to permit CANDU geometry modelling. The current efforts involve validating the output of the code, comparing results against other codes as well as benchmark experiments. This includes comparing lattice physics results such as k_∞, coolant void reactivity, and depletion, as well as looking at intermediate calculations, such as the self-shielded cross-sections from the embedded self-shielding method (ESSM) of Polaris. The code-to-code comparisons performed so far show that Polaris achieves comparable results to other codes. However, to improve accuracy, it is recommended that the analyst recalculate the self-shielding factors within the multigroup nuclear data library using homogeneous mixtures rather than pin cells. (author)