The basic effect of lowering the inlet to 150 mm is a noticeable reduction in the inhomogeneity of the flow distribution along the depth and height of the mockup. Conditions, close to those for stabilized flow, were created at 150 mm from the upper edge of the inlet, thanks to which a section of low variation of the flow with channel length (250 mm ~ s ~ 600 mm) was observed in a significant part of the zone of "closed" cross sections. The flow inhomogeneity in a series of mockups decreased to a value vmax/v min = 1.7 instead of 3 in mockups with an inlet height of 350 mm (the section length s is 500 mm and 300 n~n in Figs. la and ib, respectively). If the inlet is wide (Hin/H r = 2), inertial effects are insignificant and the flow is close to "potential" flow with a maximum velocity (wmax/w = 1.19) at Power Physics Institute (FEI). Translated from Atomnaya Energiya, Vol. 71, No. 2,'pp.