Failure of the penstock. Four linear feet of the five foot diameter penstock was completely torn away (structural failure). Damage included erosion of side hill and embankment adjacent to the powerhouse, spill of lubricating oil, tipped over transformers, local power outage, flooding of the powerhouse about three to four feet with mud, and extensive damage to one of four generators.
Failure Mode
Riveted steel penstock ruptured
Effect
Penstock rupture caused erosion of fill and flooding of the powerhouse. This, in turn, caused a powerhouse shutdown, release of oil into the river and knocking out a local distribution line.
Storage Lost
FALSE
Fatalities
0
Remedial Action
Licensee investigated cause of the rupture and replaced pipeline and penstocks from May 1999 to January 2000.
