Importance of coolant densities in TRITON self-shielding calculations for the Canadian SCWR

In calculating lattice physics phenomena for the Canadian SCWR using TRITON, fluid densities and temperatures are important in the self-shielding calculation. In this paper, we investigate the effect of coolant properties on self-shielding in the SCALE code system, and show that some phenomena, such as Coolant Void Reactivity, are highly sensitive to these properties. In particular, limits on SCALE parameters and models can cause anomalous predictions, even when all lattice parameters appear consistently identified. A new methodology is proposed that overcomes some of these limitations by specifying an appropriate coolant density and provides results more consistent with other codes.