Extensive simulations indicate that in most but not all cases the single- a
nd two-phase models predict similar dynamic behavior of a reverse-flow reac
tor; when catalyst pellet multiplicity does nor occur at any point in the r
eactor. Differences in the predictions are found in some cases close to the
dynamic bifurcation loci of a cooled RFR, or in others when the qualitativ
e dynamic behavior is very sensitive to the value of the parameters, such a
s close to a transition to chaotic behavior. The two models can lend to rat
her different predictions of the dynamic features when there are large diff
erences between the feed and coolant temperatures.