Tube Rolling and Pop-a-Plugging a Success
Tube Rolling and Pop-a-Plugging a Success
(OP)
thread794-280095: Expansion Versus Weld Repair
Just to let you know, (because Yamoffathoo cannot), inspections of four degraded bleed condenser tube sheets confirmed that control valve modulation caused thermal transients in the un-rolled tube sections that mechanically fatigued the root of the seal welds, flooding the tube annuli causing progressive collapse and released tubes to migrate down the tubesheet.
Also confirmed was that mixed mode operation (sprays and reflux or leaky rolled tube spray and reflux) caused core tube flooding and steam void collapse that resulted in fretting between tubes and baffle plates.
Several bleed condenser tubesheets have been successfully rolled, severely buckled and/or significantly migrated and/or significantly fretted tubes have been Pop-a-Plugged and placed back in service.
Just to let you know, (because Yamoffathoo cannot), inspections of four degraded bleed condenser tube sheets confirmed that control valve modulation caused thermal transients in the un-rolled tube sections that mechanically fatigued the root of the seal welds, flooding the tube annuli causing progressive collapse and released tubes to migrate down the tubesheet.
Also confirmed was that mixed mode operation (sprays and reflux or leaky rolled tube spray and reflux) caused core tube flooding and steam void collapse that resulted in fretting between tubes and baffle plates.
Several bleed condenser tubesheets have been successfully rolled, severely buckled and/or significantly migrated and/or significantly fretted tubes have been Pop-a-Plugged and placed back in service.




