Published in Entergy ANO 2R18 Newsletter Day 34
ANO Main Transformer Replacement Is a Shared Resources/Entergy System Success Story
Recent replacement of Arkansas Nuclear One’s “A” main transformer is a success story that illustrates Entergy Nuclear’s broad-based fleet advantage and effective coordination with Entergy’s Transmission organization. About a week after the Sept. 19 start of ANO’s 18th Unit 2 outage for refueling, planned visual inspection of Unit 2’s three main transformers by ANO and Entergy Transmission employees revealed loose blocking in the upper area of the “A” main transformer. The proposed remedy, transformer replacement, was confirmed by General Electric and Entergy Transmission as the right thing to do. Main transformers “B” and “C” checked out satisfactorily and will be return to service for Unit 2’s upcoming operating cycle.
A team with Jeff Heckenberger, director of planning and scheduling and outages for Entergy Nuclear South, as the lead was assembled to work through Unit 2’s emergent transformer replacement issue. Team members included ANO and Shared Resources management, field supervision and engineering expertise with vendor support provided by Stone and Webster craft and Barnhardt Services which handled the heavy lifts.
Scheduled inspection of main transformers during the early phase of the outage was a prudent measure that paid off by leaving time to work an extensive emergent transformer replacement in parallel with other planned outage work. This planned inspection is an excellent example of doing the right things to ensure equipment reliability during Unit 2’s upcoming operating cycle.
In 2003, ANO had a similar experience replacing two transformers during a sudden Unit 1 forced outage caused by a lightning strike. There were no available spare transformers on site at the time. The outage lasted 26.5 days … which was considered an amazing turnaround considering the lack of available spares and the amount of work that was performed.
This time, however, there were spare transformers aplenty -- three in fact -- on site and ready for service. The “A” replacement was purchased several years ago from TVA as a spare for a possible instance like this. The replacement transformer was tested recently in advance of installation to ensure its service readiness.