Konecranes, working closely with Davis-Besse engineers planned and executed the work flawlessly, completing both projects in only three days.
FirstEnergy Corporation’s Davis-Besse Nuclear Power Station, located in Oak Harbor, Ohio, uses a polar crane to lift the reactor head off the domed circular containment building every 18 months. FirstEnergy decided to replace the conductor bar for the polar crane after they noticed degraded and hanging conductor bar insulation.
To replace the conductor bar, a large scope of work needed to be done within a four-day window and all parts, tools, insulation and ladders and scaffolding would have to be set up at the job site prior to tag out. What’s more, special tools and skills were required at insulation splices and joints. To top it off, the project needed to be performed according to foreign material exclusion (FME) procedures.
At the same time as the conductor bar replacement, Konecranes modernization engineers would also be working to increase the capacity of the crane. This simultaneous project would further limit both sets of workers’ access and mobility. Mike Zawacki, a senior nuclear engineer for First Energy and crane engineer for the project, cited a variety of specific environmental problems they would have to deal with, including unknown stay times and a lack of options for a cool tent because the work location would be constantly moving.
Precise planning saves the day
Konecranes and David-Besse engineers first mocked up the entire job, including how long each task would take and the number of parts involved. Zawaki built a life-sized mock-up of the containment area, which showed where the conductor bar system was located. The plans were cut to the exact dimensions workers would be seeing when they entered the containment building.
The planning paid off—Konecranes’ Mark Stanislaski was extremely satisfied with the work performed by the 10-person conductor bar project crew. The project was completed in 3 days, with two 12-hour shifts per day, plus stay times for overexertions required by the 130°F working conditions. Five additional Konecranes employees were working on the crane modification project at the same time.