A weak weld discovered last week in a Beaver County nuclear reactor must be repaired before operations can resume.
The “microscopic” weakness in the reactor vessel head of FirstEnergy’s Beaver Valley Unit 2 in Shippingport was found during an ultrasonic exam of 66 welds around the reactor, according to Jennifer Young, a FirstEnergy spokeswoman.
“It’s nothing that you’re able to detect without instrumentation,” she said. “It’s not visible with the naked eye, but it is something that we look for and there’s an industry-proven method on how to fix these when they’re identified.”
Young said this is not a public safety issue and the repairs will not delay routine refueling and maintenance.
This is the eighth flaw found in the Unit 2 reactor vessel head since it started operating in 1987. The last weak weld was discovered in 2012.
If untreated, Young said the weld could have developed into a crack.
“Over time this material is susceptible to some weakening,” she said. “We do look for it each outage. This is something that’s known across the industry. It’s not unique to Beaver Valley and it’s not something that can’t be easily fixed.”
Young said a more resistant alloy will be patched over the existing weld strengthen it.
“This new alloy has higher levels of chromium in them,” she said, “which is less susceptible to this weakening over time and this is what is used across the industry to do these welds.”
FirstEnergy plans on replacing the reactor vessel head in 2017 and Young said this latest round of repairs will not change that schedule.
“We had planned for a long time to replace the head and the steam generators and that’s just simply because these materials age and aren’t as efficient and effective later in their life,” she said.
The reactor vessel head of Beaver Valley Unit 1 was replaced in 2006. That unit started operating in 1976.
Young would not confirm when the reactor would be back on-line.