Laser Tracking System Saves Outage Time at Calvert Cliffs

In the past, the position of inspection and repair equipment in the steam generator channel head was determined by manipulator software that geometrically computed the angle versus the length of tooling using on-board encoders. This system of positioning, although used for many years, generated information that could lead to errors in the inspection locations. Framatome Technologies (FTI) uses a laser tracking system that makes this type of error nearly impossible. This was the system used at Baltimore Gas & Electric’s (BGE) Calvert Cliffs
Unit-1 Nuclear Power Station during the spring outage.

“We used the laser tracking system to verify independently the location of eddy current probes in the steam generator,” said Mark Briers of FTI. The system uses an eye-safe laser that is reflected off a target, usually a reflective tape, located on the manipulator to give an exact location. That location is compared to the manipulator location indicated by the manipulator’s encoded software to ensure that the systems report the same location. Laser tracking eliminates potential mistakes caused by system calibrations and human inputs. It also increases eddy current inspection rates, and plugging and repair processes as well.

“From my perspective,” said Jim Adams, BGE Steam Generator Project Engineer and Startup Coordinator, “the laser positioning system worked well and saved outage time. It utilizes the latest technology and I would encourage its use at all facilities where time and quality are of the essence.”

FTI’s process will be used again at several utilities during the fall 2000 outage season and for the Calvert Cliffs Unit-2 inspection next spring.