December 05, 2017

USA: AREVA NP Maintenance Technique Reduces Frequency of Component Inspections at Two Exelon Plants

The Nuclear Regulatory Commission (NRC) recently granted inspection relief to Exelon’s Byron Unit 2 and Braidwood Unit 1 following use of AREVA NP’s innovative cavitation peening mitigation technique on each unit’s reactor vessel closure head (RVCH). With this approval from the NRC, Exelon can now start the transition from inspecting the components every 18 months to once every 10 years.

AREVA NP applied its cavitation peening technique for the first time on an in-service RVCH at Byron Unit 2 in spring 2016. Subsequently, AREVA NP teams implemented the technique on the RVCHs at Braidwood Units 1 and 2, and Byron Unit 1.

An alternative to component replacement that supports a more efficient operation of the nuclear fleet

“At AREVA NP, we support the U.S. nuclear energy industry by developing innovative solutions to help the nuclear fleet operate more economically and efficiently,” said Craig Ranson, senior vice president of the Installed Base Business Unit in the United States. “Our cavitation peening technique is a proven alternative to component replacement that supports facilities like Braidwood and Byron with reliable and cost-effective asset management.”

Cavitation peening: an innovative solution to extend the life of the components

Cavitation peening can be applied to RVCHs and other primary components that experience primary water stress corrosion cracking. It uses ultra-high-pressure water jets to generate vapor bubbles that collapse with enough force to create beneficial compression of the components’ surfaces.

This surface compression improves the components’ material properties and enhances resistance to corrosion and other types of degradation, which reduces the effects of aging.

Cavitation peening extends the life of the components for more than 40 years and can be used on all reactor designs.