May-June 2019 NPJ

(Continued on page 50) ARMOR Fuel Rod Protection By JohnathanChavers, Southern Nuclear Operating Company. Johnathan Chavers Johnathan Chavers earned a Bachelor of Science in Nuclear Engineering from the University of Tennessee. Johnathan has experience working in several work groups at Plant Hatch and in the Nuclear Fuel Department of Southern Nuclear. Early in his career, Johnathan served as a Senior Core Management and Design Engineer. Currently, Johnathan serves as the BWR Fuel Engineering Manager providing technical and strategic direction of BWR nuclear fuel cycle analysis, reload safety analysis, reload licensing, reactor engineering support and oversight, dry fuel storage characterizations and evaluations, and project management of large initiatives. The Nuclear Energy Institute’s Top Innovative Practice Awards highlight the nuclear industry’s most innovative techniques and ideas. This innovation won the 2018 GE Hitachi Nuclear Energy Vendor Award. The team members who participated included Johnathan Chavers, BWR Fuel Engineering Managers, SNC; Patty McCumbee, Product Line Leader, GNF; Yang Pi Lin, Materials Engineering Lead, GNF; Sarah Desilva, Materials Engineer, GNF; Marty Swan, Project Manager, GNF; Vickie Perry, Customer Project Manager, GNF; Nick Satterlee, BWR Fuel Engineer, SNC; Randy Dunavant, Lead BWR Fuel Engineer, SNC; and Aaron Phillippe,BWR Fuel Engineer, SNC. Overview The nuclear power industry is at a crossroads. If we do nothing to change, the status quo may result in a reduction of nuclear power generation in the U.S. To thrive, we in the nuclear power industry must take a different path – a path that requires innovations like the kind that formed our industry in the 1950s and 60s. The innovation of a coated Zircaloy- based cladding material described herein is the type of change our industry needs to thrive. The GNF fuel rod oating was devel- ped to provide both debris resistance and mproved corrosion erformance under normal conditions nd design-basis ac- idents. Recognizing ts dual benefits, the oating is referred to s ARMOR (Abra- ion Resistant, More Oxidation Resistant). The abrasion resistant unction is important ecause the industry ontinues to struggle with debris-related fuel leakers. Debris fretting of fuel rods is the only remaining cause of failure in Global Nuclear Fuel (GNF) bundles. Once GNF determined ARMOR was a viable fuel rod coating, Southern Nuclear and the GNF team part- nered to significantly accelerate early de- velopmental installations into a commer- cial reactor. Southern Nuclear and GNF entered a joint program in 2017 to deploy four (4) lead test assemblies (LTAs) with ARMOR coated fuel rod segments in Hatch 1 Cycle 29. The objective of the program was to design, qualify and fab- ricate segmented rods that could be im- plemented in the Hatch reload in spring 2018. The segmented rod design and four-bundle configuration in the core al- lows the bundles and rodlets to be cycled as necessary and provides easier harvest- ing and testing of the segments. The timeline for deployment of the new technology was aggressive for both GNF and Southern Nuclear as most fuel design changes occur over multiple years. In less than a year, GNF developed and qualified the segmented rod-coating process, the segmented rod design and manufacturing process. The hard, coating applied to the existing fuel rod is expected to decrease or prevent the occurrence of debris leakers. The LTAs allow us to visually observe coating performance in reactor. This, along with extensive out-of-reactor testing, will confirm the design basis and licensing requirements for this fret- resistant coating technology deployment. Southern Nuclear accelerated standard design change processes to ensure rapid deployment of the ARMOR technology. TheARMOR LTAs were delivered to Hatch in December 2017 for irradiation in Hatch-1 Cycle 29 (beginning operation in spring 2018). The innovative coating provides complete protection against debris fretting in the areas of the fuel rod to which it is applied. The additional oxidation margin it provides will likely be leveraged for accident tolerant benefits as well. The following is a summary of how the ARMOR LTAs delivered to Hatch meet the NEI award criteria. Innovation Installing a new material into the active region of the reactor core is, by definition, challenging and requires innovation to be successful. This is particularly true when such a task is to be performed in less than a year from project initiation. The following innovations are noted:  Managing a first-of-kind science- based supply chain to provide coating in product form with quality pedigree suitable for in-reactor testing.  Accelerated and advanced engineering analyses to assure these rod segments were suitable for installation and met licensing criteria for the site.  Special engineering tests at normal and severe conditions to establish confidence in the design.  Advanced welding development, diagnostics and imaging to characterize the specimens and other manufacturing processes.  Special nuclear modeling to demonstrate acceptable impacts on 48 NuclearPlantJournal.com Nuclear Plant Journal, May-June 2019 c o i p a c i c a s f b c