Preliminary Fabrication of Fe-based Alloy Cladding for Nuclear Fuel

The enhanced ATF cladding can be defined as a cladding that can tolerate accident situations for a considerably longer time period while having a similar or better the fuel performance during normal operation. Various concepts of enhanced ATF cladding have been developed by fuel vendors, national laboratories, and universities. Framatome and Westinghouse is developing two different types of cladding that are Cr-coated cladding and SiC cladding. General Electric and Oakridge National Laboratory (ORNL) cooperated to develop a Fe-based alloy cladding called IronClad (FeCrAl). Nippon Nuclear Fuel Development (NFD) also developed FeCrAl-ODS cladding. Taking all the aspects of enhanced ATF cladding into consideration, KEPCO Nuclear Fuel (KNF) focused on Fe-based alloy as one of the convincing candidate materials for enhanced ATF cladding. The Fe-based alloy cladding has advantages of better corrosion resistance and excellent high temperature oxidation resistance compared to commercial Zr-based alloy cladding. On the other hand, this alloy does not have good fabricability owing to its high strength. In this study, fabrication process of Fe-based alloy cladding was selected, and preliminary fabrication was conducted through the process. At last, KNF's present and future work on Fe-based alloy cladding were introduced. From the paper review, it was noticed that 3-roll pilgering process is one of the best way to fabricate a thin wall cladding. Preliminary fabrication of Fe-based alloy cladding was conducted by foreign manufacturers. This process includes alloy casting, master bar production through forging and rolling, gun-drilling and pilgering. As a result of this attempt, Fe-based alloy cladding having precise dimension was fabricated very successfully. From the fabrication experience, Fe-based alloy cladding developed by KNF and KAIST is fabricating, and KNF's project that produces ingots and claddings with large quantity at commercial process will be initiated soon.