b'Accomplishments:including linear heat generation a.Murdock, Oldham, Fielding, andrate and configuration of the ex-Curnutt completed the final ex- periment. These pins will provide periment fabrication, assembly, as- a first look into the actual viability built analysis, and insertion of theof FAST testing and the impacts first phase of FAST experimentsof scaled irradiation effects. The into the ATR. These experimentremaining experiments will con-scope included a series of U- tinue irradiation in ATR and be 10Zr (10 weight %) 75% smearcharacterized accordingly.density alloy fuel pins in thec.Beausoleil and Capriotti led a following designs: conventionalphenomena identification and sodium bonded solid pin con- ranking table (PIRT) effort trols; sodium free annular pins;between INL and Oak Ridge sodium bonded solid pins with ZrNational Laboratory for U-Pu-Zr liners inside of the cladding; andfuel in SFRs and the Versatile Test sodium bonded solid pins with anReactor (VTR). The PIRT results additional 3-4% alloy additives ofare important for being able to Pd, Sn, and Sb. The first irradia- plan future experiments and to Figure 2. Assembled FASTtion of a FAST experiment was aguide post-irradiation examina-rodlets. Each rodlet contains acritical success for the accelerated 0.75 long fuel pin that is scaledfuel qualification efforts beingtion (PIE) efforts from FAST. atof the radius of standardWhile the first phase of FAST Experimental Breeder Reactorsupported by multiple laborato- does not include the U-Pu-Zr (EBR-II) or AFC fuel pins. Eachries and industry partners. ternary fuels, ternary fuels are a capsule can hold up to two of these rodlets, notionally ab.Murdock, Capriotti, and Curnutthigh priority consideration for standard U-10Zr control rodletcompleted the planning, analysis,the second phase of FAST testing and one of the novel fueland execution of the first ship- and many of the phenomena designs to be tested. ment of irradiated FAST pinsassociated with the ternary fuels into ATR. As-run power historiesare highly relevant to the U-Zr suggest burnups of FAST pinsbinary fuels currently being tested. ranging from 2 %FIMA (fissionsThis is documented in an article of initial metal atoms) to nearlypublished in Nuclear Technology 7 %FIMA. The range of burnup is(Beausoleil et al., 2021).a product of different parameters 120 2021|AFC ACCOMPLISHMENTS'