b"4.1 FUEL ROD RE-FABRICATION AND INSTRUMENTATIONFuel Rod Re-fabrication and InstrumentationPrincipal Investigator: Jason SchulthessTeam Members/ Collaborators: Dan Wachs, Colby Jensen, Joe Palmer, Spencer Parker, Evans Chambers, Kim Davies, Gene Matranga, Cad Christensen, Jordan Argyle, Mark Cole, Collin Knight and Todd PaveyThe ability to extractF ollow-on irradiation testing ofthe surface for welding new endcaps, previously irradiated fuel rodswelding the new endcaps in place, fuel from the reactor,enables highly instrumentedevacuating the rodlet and backfilling re-fabricate, andexperiments to be performed. Thiswith the desired gas mixture to the install instrumentationtesting allows researchers the abilitydesired pressure, seal welding the at the critical testingto assess the state of the fuel at anyrodlet, and inspections. Enabling these points is an essentialpoint in its life cycle. Follow-onre-fabrication tasks requires designing, capability that doesirradiation testing is currently targetedprototyping, and testing the Rodlet End not exist today. to be performed using the TransientWelding System to perform these func-Test Reactor (TREAT) and Advancedtions prior to final equipment being Test Reactor (ATR) at Idaho Nationalapproved for installation in the hot cell Laboratory (INL). The ability to(5d window).Application of limited process preirradiated fuel rods of anyinstrumentation to the rodlet will be length to achieve the desired formpossible in this system.factor and include instrumentationsFor advanced rod measurement providing online measurements is adesigns, a complementary reinstru-crucial capability to support testing ofmentation system is under develop-Accident Tolerant Fuel (ATF) fuels. ment in collaboration with Halden that Project Description will provide a modular and flexible Performing irradiation testing requiresplatform for performing precision the ability to re-fabricate previouslyoperations and handling of delicate irradiated fuel rods within INL's Hotinstrumentation. The state-of-the-art Fuel Examination Facility (HFEF) dueHalden reinstrumentation process to the high radiological doses of theentails neutron or x-ray radiography, irradiated fuel. The scope aims to estab- cutting and drilling out the fuel at the lish basic re-fabrication capabilities atends of the rod, removing the oxide INL to enable these follow-on irradia- layer from cladding surfaces, cryogenic tion experiments. Basic re-fabricationfreezing (e.g. filling the rod with liquid consists of inspection to determine theCO2 and freeze in liquid N2), drilling desired segment to be cut from thea rod center hole for instrumentation, source material, sectioning or cuttingoutgassing in vacuum, insertion of the segment, de-fueling the ends of thecenterline thermocouples, welding rod segment to make space for the instru- end plugs, adding inert gas and seal mentation and new rodlet endcapswelding, and conducting helium leak to be welded in place, removal of thechecks. This system will allow INL to oxide layer from the ends to prepareadd instrumentation to irradiated fuel rods and improve future testing.146 2020|AFC ACCOMPLISHMENTS"