AREVA offers products and services that can help achieve top plant performance.
We share a common goal with our customers: to harness the highest level of expertise, innovation and in-reactor experience feedback for safe and successful fuel operation that improves performance, without compromising safety margins. Utilities want to maximize power output and uranium utilization through optimized fuel design and operation. To get there requires high-quality fuel, on-time delivery, optimal core management, and close daily collaboration between utility engineers and AREVA experts.
AREVA has implemented debris filters on all of our fuel designs, including the FUELGUARD™ filter, which has improved debris resistance due to the curved, non-"line-of-sight" flow path. In addition, our Fuel Manufacturing facilities implemented an improved Foreign Material Exclusion (FME) program and training, which address both debris and contamination control. Likewise, our Outage Services organization implemented an improved FME program based on the utility model (use of zones, focus on prevention) to prevent introduction of foreign material during refueling outage work. We continue to strive to improve FME aspects of equipment designs, greater use of human performance tools, advanced debris filters on all fuel designs, and other debris resistant design features.
Pellet-Clad Interaction (PCI)
Our chip-resistant pellet design, manufacturing specification, and inspection protocol has resulted in zero PCI failures in AREVA fuel since we implemented these standards in 2004. We continue to develop improvements in core monitoring capabilities to further reduce the risk of PCI while at the same time providing increased operational flexibility — the XEDOR™ system has been demonstrated in operation at a US BWR. AREVA has the capability to perform cycle risk assessments for PCI to manage changes to operating conditions while maintaining margins to failure.
AREVA has developed XEDOR™ to improve PCI management and enhance reliability. This tool draws on AREVA’s extensive thermal-mechanical modeling expertise to provide a mechanistic approach to Pellet-Clad Interaction (PCI) management as a replacement of empirically based maneuvering guidelines.
The primary use of XEDOR™ is for on-line monitoring of the mechanical condition of fuel rods in the core as the basis for power maneuvering. The mechanical state of the fuel is recalculated with every core monitoring update to maintain up-to-the-minute details on the state of the cladding and fuel pellets in every 6-inches of every rod in the core. This inherently captures the effects of any extended local deconditioning, regardless of how close actual operations followed historical experience. Operators can use this information to assure a consistent level of conservatism in margins to PCI failure risk while also recapturing capacity factor lost to excessive conservatism in setting power reductions, ramp steps, and ramp rates.
XEDOR™ is also a very useful tool for offline analyses. Cycle designers can utilize this tool to characterize the level of PCI risk for a specific core loading and operating sequence relative to preceding cycles. When plant operations change significantly, such as first time operations at Extended Power Uprate, XEDOR™ can be used to design the startup sequence for low PCI risk. When a fuel failure is detected, XEDOR™ can be used to determine the probability that it is PCI related and prioritize flux tilt testing to isolate the failed fuel while still incore.
XEDOR™ provides the first ever quantitative approach for managing PCI risk.
GTRF has been the leading cause of fuel failures in PWRs. AREVA’s HTP fuel design is a proven solution for grid-to-rod fretting in all PWR plant types. The HTP fuel assembly with HMP bottom grid has never experienced a grid-to-rod fretting failure. Wear measurements on discharged HTP fuel have confirmed low levels of wear and significant margin to failure.
Crud and Corrosion
Crud & Corrosion
AREVA has developed chemistry guidelines to prevent excessive crud, and has also developed thermal-hydraulic and chemistry analysis tools which lead the industry in the ability to model crud. These tools enable us to perform risk assessments to manage changes to chemistry and operating conditions while maintaining a crud-safe operating environment. For PWRs, the M5® fuel rod cladding has shown excellent corrosion resistance, and maintains significant margins to licensing limits and fuel failure in a range of chemistry and operating conditions.