Wartsila is experimenting with two new exhaust bellows materials at Antelope-Elk for the exact same reason as you detailed above. We are currently planning on replacing all of ours at 8000 hours or ~2000 Starts. We are also doing seasonal boroscopes to the best of our ability with limited access points.
Hopefully by the time they are replaced at the next interval there will be a fix that allows us to operate reliably.
Wartsila did an RCA and we had analysis done by a 3rd party. Findings were that the failure was due to thermal fatigue. Wartsila still wouldn’t say that the maintenance need was starts related and decided to put R&D into improving the bellows so that it would not fail. You can give me a call if you have any questions.
Ops. Mgr. Antelope Elk Energy Center