Transient LOFA computations for a VHTR using one-twelfth core flow models

For the LOFA transient condition, this study employs both laminar flow and different turbulence models to characterize the phenomenon of natural convection. The result of Realizable k-ɛ turbulence model (RKE) model is the most conservative one in the heated blocks (channels) regions, but the result of laminar flow is the most conservative one in the plenum regions. The comparisons of the results from large and small models suggest that large flow model is needed to obtain accurate prediction.