In aging U.S. nuclear power facilities, one of the biggest expenses is the replacement of components due to wear and degradation, such as the reactor vessel closure head. By proactively peening such components, utilities are extending the life of reactor components, in turn extending the life of the reactors and their generation of low carbon electricity.
Rather than allowing operational stresses to create multiple, random fractures on a component’s surface, cavitation peening creates compressive stresses on the surface of the material in a controlled manner—resulting in a texture similar to a golf ball’s surface, but with much smaller indentations.
AREVA’s peening process uses submerged, ultra-high-pressure (UHP) water jets to work the surfaces of reactor vessel components. The high-pressure water flow creates cavitation bubbles. As these vapor bubbles collapse on the component’s surface, shock waves travel into the material and create compressive residual stresses, which improve fatigue life, damage tolerance, and enhanced resistance to corrosion.
- Stops primary water stress corrosion cracking (PWSCC)
- Eliminates the risk of emergent reactor vessel closure head (RVCH) nozzle and reactor vessel bottom mounted nozzle (BMN) repairs
- Lower cost than repair or replacement
- Both outer diameter (OD) and inner diameter (ID) nozzle surfaces are mitigated
- Additional schedule and cost savings when In-Service Inspection (ISI) and surface mitigation scopes are combined
- No harm to component surfaces
- Process uses only water from the reactor cavity; no foreign matter exclusion (FME) concerns
- Does not leave abrupt edges between peened and non-peened regions
Yes, a picture is worth a thousand words; take a look at the cavitation peening infographic.
Since AREVA’s UHP Cavitation Peening operates at a higher pressure than many providers, our process achieves higher depth of compression and faster work completion, leading to a lower overall implementation schedule. Even better, the UHP cavitation peening mitigation of a group of reactor vessel nozzles is often less expensive than nozzle repairs.
Watch cavitation peening in action!