Hydrogen was found to be leaking from a vent line during cryogenic loading operations. The leak was attributed to a cracked weld on a hydrogen vent line that consisted of (1) double wall aluminum piping and (2) slotted spacers between the inner and outer line to provide a hydrogen gas blanket for insulation. The weld that failed was repaired using a "clamshell" over the area of the failed weld in order to support continued operations. A portion of the failed weld was removed for analysis prior to the repair.
Hydrogen Leak Through Pinhole Weld Defects in Stator Cooling Water System Forces Nuclear Plant Shutdowns
Hydrogen and water leakage in the main generator stator cooling water (SCW) equipment forced two separate shutdowns of a nuclear plant in a three-month period. Manufacturer weld defects on the SCW exciter end ring header are the likely cause for the hydrogen leakage.