Had a tube sheet leak in a feedwater heater outside Detroit last month

I was working a shutdown at a power plant near Detroit and we found this small leak in a feedwater heater tube sheet. The thing was dripping condensate right into the channel head and we had to figure out if it was a tube end failure or a sheet crack. I used a borescope to look inside and spotted a pinhole right where the tube met the sheet. We ended up expanding the tube and seal welding it on the spot. Anyone else run into tube sheet leaks that looked small but took forever to fix right?

3 comments

3 Comments

young.ryan3d ago

small leak that took forever to fix right" is exactly why I disagree with patching these things in the field at all. I've seen too many seal welds that looked good for a month then cracked open again because the tube sheet was already stressed from the original leak. Instead of spending 8 hours on a borescope and a temp fix, you should have called it a day and planned a full retube or replacement. A pinhole like that is usually a sign the whole sheet is fatigued, not just one spot. The time you spent rigging up a temporary weld could have been used to shut it down properly and avoid coming back next quarter for the same problem. Shortcuts like that just push the repair bill to later.

wendy_henderson213d ago

So you're saying he should've just told the plant manager "nah, let's shut down for a month" instead of trying to fix it? lol sounds like a fun conversation.

lucast813d ago

True but a pinhole leak doesn't always mean the whole tube sheet is shot, sometimes it's just a single bad tube from vibration or erosion. A borescope can tell you pretty quick if the surrounding ones look solid or not.