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Mechanical Breakdown: Steam Turbine Blade

A recent 170-megawatt steam turbine loss at a combined cycle power generation facility demonstrates the cost associated with turbine repairs. In this event, one of the 40-inch last-stage blades of the low pressure section of the turbine (L-0) broke, impacting several adjacent blades of the same stage. The turbine tripped due to high vibration, and shut down accordingly.

The cause of the loss remains under investigation. The initial repair estimate is nearly US$3 million and includes the replacement of the blades (accounting for half of the total cost), opening and closing the unit, blade balancing/replacement, diaphragm and coupling alignment, rotor inspection, unit transport and other fees. An extended forced outage is anticipated.


In the last 10 years, FM Global clients have experienced 166 losses involving broken turbine (steam and gas) blades. The average gross loss is US$5.7 million.

FM Global has developed Loss Alerts in support of the insurance relationship with its clients. This information is provided for purposes of illustration only. FM Global does not address life, safety, or health issues. No liability is assumed, and no duty to any party is undertaken, by or through the use of this information. The liability of FM Global is limited to that contained in its insurance policies.

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