Damage to Summer 2 containment vessel

Tuesday, 24 February 2015

The US Nuclear Regulatory Commission (NRC) has started inspecting the construction site of VC Summer unit 2 for the cause and impact of "inadvertent damage" to its containment vessel. 

VC Summer unit 2 construction site in December 2014 (Image: SCE&G)

According to the NRC, workers from Chicago Bridge & Iron (CB&I) cut some safety-related reinforcing bar and damaged the containment vessel bottom head while drilling into concrete. The incident occurred during the week of 9 February.

CB&I informed Scana Corporation, parent company to plant owner South Carolina Electric and Gas (SCE&G), of the damage on 16 February, which then informed the NRC.

The NRC said today that a three-man team had now started a special inspection at the plant. The team will review the events that led to the damage and both CB&I's and Scana's assessment, as well as develop its own assessment. The NRC said the inspectors would also "evaluate any potential effects on containment vessel integrity, any similar activities and corrective actions".

The inspection team is expected to remain on-site for about one week. A report documenting its findings will be publicly available within 45 days of the end of the inspection.

NRC regional administrator Victor McCree said that, although the actual damage "appears to have been minor", the agency wants to make sure it completely understands its potential impact and any apparent breakdown in the controls that might have prevented it. "We are also concerned about the delay in CB&I reporting the issue," he added.

"The damage appears to be minor," Scana spokesperson Rhonda O'Banion told World Nuclear News. "We are assessing the condition, conducting the evaluation and identifying corrective actions. Our focus is firmly on quality and safety."

A Westinghouse/CB&I consortium is building two 1117 MWe AP1000 reactors at the Summer site. The consortium informed SCE&G in August that the project faces a delay of at least one year for each unit. The "substantial completion" of unit 2 is now expected in late 2018 or the first half of 2019, while that of unit 3 may be about 12 months later. The delay was attributed to the fabrication and delivery of structural modules from CB&I's facility in Lake Charles, Louisiana.

O'Banion said, "As we recently reported in our Base Load Review Act quarterly report to the Public Service Commission, the consortium has indicated that the substantial completion date of unit 2 is expected to occur by June 2019. The consortium's preliminary schedule has not been accepted by SCE&G and is under review, but SCE&G cannot predict when a revised schedule will be resolved with the consortium."

Researched and written
by World Nuclear News