b'Completion of ATF-1 Experiment SeriesPrincipal Investigator: David KamermanTeam Members/ Collaborators: Chris Murdock, Klint Anderson, Jason Brookman and Changhu XingThe ATF-1 experimentT he ATF-1 experiment was partof 2015 in ATR cycle 157C and of the Feasibility and Assess- concluded in January of 2020 after ATR allowed for thement phase of the Accidentcycle 166B. The rodlets were irradiated prioritization of leadingTolerant Fuel (ATF) program. Testat prototypic linear heating rates ATF concepts such asrodlets made of entirely new fuelbetween 200400 W/cm. Cladding coated Zircaloy andand cladding materials were tested intemperature was controlled using a gas FeCrAl cladding. Drop-in-Capsule experiments in thegap between the rodlet and capsule. small I test postions in the AdvancedAccomplishments:Test Reactor (ATR) reflector. The testA total of 31 test rodlets were design provide prototypic nuclear andirradiated in the ATF-1 experiment thermal conditions but without thewith the highest burnup pin being hydraulic environment found in lighta Uranium Silicide pin that reached water reactors.45 GWd/MTU. Testing showed that Project Description: Uranium Silicide performed well The ATF-1 experiment test trainunder irradiation with minimal consists of the basket, top spacer,swelling and fission gas release. and seven vertically-stacked capsuleHowever, this fuel concept has been assemblies and/or dummies in eachdiscontinued due to the materials of the three channels (for a total ofunfavorable reaction with water. twenty one (21) capsules/dummiesTesting on the SiC doped UO 2was per basket). The capsule used in theless favorable with high amounts of experiment provides the pressureporosity seen in the pellets even at boundary for the experimentallow burnups. Burnups and power materials located within. In thehistories for all of the rods involved event of a rodlet cladding failure, thein the experiment are available and stainless steel (316L) capsule preventshave been provided to the respective fission products from entering theindustry parties. The power history of ATR Primary Coolant System (PCS).the ATF-07 capsule which contained Figure 1. ATF-1 Rodlet andThe test rodlet is intended to representa FeCrAl clad fuel rod is shown in Capsule Design a miniature length Pressurized WaterATF-07 Power History. Cladding Reactor (PWR) fuel rod, nominallytemperature data can be determined prototypic in the radial dimensionfrom a polynomial correlation with consisting of 10 pellets. A typical ATF 1the rod power. The correlation is capsule and rodlet assembly is shownderived from a finite element model in ATF-1 Rodlet and Capsule Designof the rodlet and capsule. An example below. Concepts irradiated includedrelationship for the ATF-07 capsule Uranium Silicide and Uranium Nitrideis shown in Cladding Temperature fuels, Uranium dioxide with SiliconCorrelation for ATF-07. Further test Carbide dopants as a fuel, and FeCrAldata can be found on the ATF database cladding. Irradiations began in Januarywebsite at atf.inl.gov. The design of 82 2020|AFC ACCOMPLISHMENTS'