Employees of Exelon Corporation were awarded the Nuclear Energy Institute’s Top Industry Practice (TIP) award yesterday in the Materials and Services category for their application of new, underwater laser scanning technology to obtain measurements within a BWR vessel at Quad Cities Generating Station in Cordova, Illinois. The scanning technology, developed specifically for the nuclear industry by Newton Labs of Seattle, Washington, was used to capture precise, as-built dimensions underwater, within the constricted high-radiation belt-line region of a reactor.
The situation that led to the award unfolded during a 2011 scheduled outage of Quad Cities Unit 2, when a degradation of the RS-2 weld on jet pump 13/14 was observed. It was determined that a modification would need to be designed, fabricated and installed during the next refueling outage in two years. The problem at the time was that there were no sufficiently detailed as-built records available to accomplish this, and the only opportunity to acquire new measurements was during the outage in progress, which would soon be ending.
The nuclear underwater laser scanner system, named the NM200UW, is a landmark technology developed by Newton Labs and combines industrial-grade hardware and electronics with Newton-developed software that compensates for the disruptions of refraction, turbulence, heat and radioactivity, characteristic of the in-vessel environment. The scanner output is a point cloud so detailed, that when utilized with industry standard three-dimensional software, a fully measurable CAD model can be generated. With a demonstrated accuracy of 0.005 in. (0.127 mm), or better, the technology in many cases eliminates the need for less-accurate traditional measurement techniques such as video scaling or a ruler attached to a handling pole.
With the outage clock ticking, Exelon assembled a Quad Cities coordination and support team to shepherd the critical scanning and imaging process. The team was comprised of Thomas Wojcik, Chris Hebel, Ron DiSabitino and Kate Gresh. Design engineers provided a list of measurements that would be needed in order to plan any modifications. Over 20 scans were taken during the 12-hour period allotted for the process, capturing all but one of the requested dimensions. The 20-plus point clouds were stitched together using 3-D post-processing software and the resulting accuracy of the detailed images was significantly better than previous measurement methods.
The TIP award was made on May 22 during the Nuclear Energy Assembly (NEA).
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