A method to inspect process streams developed by Pacific Northwest National Laboratory, Richland, Wash., takes a double-pronged approach to spotting foreign objects; by doing so, it provides more data and, in turn, greater accuracy. Our method is the only one were aware of that uses both acoustics and optics, says Aaron Diaz, staff scientist. Our process involves multiple sensors configured along the process stream, he notes. We flood the stream with sound pulses of acoustic energy, while at the same time transmitting optical energy. Were looking for reflected echoes that we can correlate with location, such as depth and lateral position, in the stream relative to the products flow rate. The technique can replace more costly and slower inspection methods such as X-raying, he adds. Because it can be automated, its inherently safer and more effective than inspecting certain types of process streams manually.