b'hot-cell were completed and in-cell checkout/demonstration performed. For base facility infrastructure, a new control system was fabricated and installed, including installing new feedthrough cables in the hotcell wall to support experiment assembly and instrumentation checkout. An entirely new feedthrough was fabricated and installed to support the power and control requirements for the welding systems. The HFEF-15 cask was returned to service following the completion of maintenance, upgrades, and readiness reviews. New electrical power and gas supply were routed to support the experiment assembly, welding systems, and the upgrades to the in-cell mill.Defueling development was twofold and included both mechanical and wet/chemical defueling processes. The existing HFEF in-cell 3-axis mill was Figure 2. Surrogate fuel rodlet withAdditionally, the capability to assemblesuccessfully modified to incorporate ends successfully mechanicallyirradiation experiments with previ- a 4th-axis rotation stage and vacuum defueled using newly installed in-cell equipment ously irradiation fuel was developedcollection system. Following successful and demonstrated with the successfulinstallation, mechanical defueling and assembly and shipment of the ATF-Rpreparation of cladding tube ends for experiment in the Minimal Activationwelding was demonstrated on the Retrievable Capsule HolderStaticin-cell system, including removal of the Environment Rodlet Transient Testcladding oxide layer. Apparatus (MARCH-SERTTA) experi- Wet/chemical defueling utilizes an acid ment vehicle. bath to dissolve the fuel and remove Accomplishments:it from the cladding. This process uses During FY2021, final designs of6M HNO 3heated to near boiling equipment and methodologies were(~150 C). Once at temperature, completed enabling fabrication tothe fuel sample is introduced to the begin and complete. Following fabri- system, and the acid etches the fuel cation all equipment was thoroughlyout of the cladding. Once dissolution tested out of cell and applicable inde- is completed, the acid bath will be pendent facility reviews completed.neutralized with MgO to eliminate the Equipment installations into thehazardous nitrates and then solidified 142 2021|AFC ACCOMPLISHMENTS'