This research continues our cooperative effort to study the effects of large-scale surface roughness on ultrasonic transmission through interfaces and updates our previously-reported results [1], The Center for Nondestructive Evaluation has developed a model for the propagation of ultrasound through a surface and into an isotropic metal and this model is undergoing experimental validation at Battelle PNL. Once validated, this model will be used as an engineering tool to study the effects of surface conditions upon an ultrasonic inspection of nuclear reactor components. The goal is to quantify and develop requirements to limit the adverse effects of surface conditions during such an inspection. Currently, there are no ASME Code requirements dealing with surface conditions during an UT inspection. Commonplace in the field are abrupt step discontinuities on the order of 1.5 mm. M. S. Good [2] has measured up to a 12 dB signal loss from a 10% through-wall notch due to a 1.5-mm step.