Validation of the Nodal Drift Method on a CANDU LOCA and First Application to the TWIGL Seed-Blanket REA

The Nodal Drift Method (NDM) has been developed for a broad and coarse safety review of promising thorium-fueled High Conversion Water Reactor (HCWR) options. Conceived as a missing link between too approximate point kinetics and too sophisticated industrial codes, NDM is based on 2-group diffusion theory and a lumped parameter model with maximized mesh size. It has been validated on a CANDU LOCA (Loss Of Coolant Accident) benchmark, without any need for thermal calculations. With same principle of pre-tabulated cross sections and as a first application to PWR-like REA (Rod Ejection Accident), the well-known TWIGL benchmark of a ramp transient within a heterogeneous core has been calculated. From its good results have been deduced a few perspectives towards future HCWR studies.