Cracked weld discovered in Duane Arnold refueling outage

NextEra Energy has begun steps to repair a cracked weld joint in a nozzle found during a refueling outage at the Duane Arnold Energy Center.

The discovery was described in a 21-page letter to the Nuclear Regulatory Commission on Nov. 6. It describes an “indication identified in the N2A Recirculation Inlet Safe End to Safe End extension Dissimilar Metal Weld.”

The report says a preliminary assessment attributes the problem to “stress corrosion cracking.” Following the discovery, three similar welds were examined using ultrasound technology, but no indications were found requiring repairs.

NextEra's letter details a repair plan that it says is based on restoring the integrity of the weld joint while limiting radiation exposure to repair personnel to the maximum extent practical.

The discovery comes just as NextEra is in the final stages of an application for a 20-year extension of the plant's operating license, which expires in 2014.

NextEra officials were not immediately available for comment on the finding.