Spatially Dependent Self-Shielding Method with Temperature Distribution for the Two-Dimensional Transport Code PARAGON

The Spatially Dependent Dancoff Method (SDDM) was recently developed to evaluate the power distribution within a fuel rod that has spatial variation of isotopic contents. The method was validated and verified by comparison to Monte Carlo calculations and measurements. However, those evaluations and comparisons were based on the assumption that the temperature distribution within a rod is flat. In this study, an equation used in the SDDM is enhanced in order to more accurately treat the temperature distribution. The enhancement was carried out with the knowledge that a Monte Carlo calculation shows no effect of temperature distribution on spatial flux within a rod. This leads to the cancellation of reaction rate changes due to temperature distribution between inner and outer regions within a rod. The knowledge gained from these evaluations was then applied to the equation used in the SDDM with the temperature distribution. The improved SDDM was validated and verified by comparison to MCNP4C calculations. PARAGON with the improved SDDM is now capable of performing micro-nuclear physics calculations with greater accuracy.