Development of Advanced Fuel Structural Integrity Evaluation Technology

Through previous 3-year research, core technology for a dual-cooled FA structures was developed to solve several structural issues, to make sure of the manufacturability of a dual-cooled fuel. The fabricated fuel assembly was utilized to perform integral mechanical tests for the fuel commercialization. In addition, For fuel rod design, not only we took an analytical approach to solve the PCI (Pellet-Cladding Interaction) problem, but also performed grid-to-rod fretting wear test for fuel failure analyses. The research results are summarized as follows: ● solving mechanical issues such as cladding different growth, fatigue analysis on welds) ● analyzing and evaluating the failure possibility ● analyzing pellet-cladding interaction by analytical approach ● evaluating structural requirements ● fabricating a dummy fuel assembly to confirm the manufacturability ● performing structural characteristic tests (static, impact, vibration) Likely, during last 2-year research period, based on carefully analyzing the recent seismic accidents, a structural integrity evaluation method has been proposed. we also built structural integrity tester, FA mechanical characteristic tester, and scratch tester for ATF cladding. The research results are summarized as follows: ● providing an state-of-the-arts for DBA and BDBA seismic accidents ● suggesting a structural evaluation method for fuels at BDBA ● establishing structural integrity evaluation testers for DBA and BDBA accident ● drawing integrity evaluation items for ATF cladding ● evaluating mechanical integrity of ATF cladding (Fe-Cr-Al, Cr-Al).