b'The IRT tests have fabricated, irradiated, and performed post irradiation examination on fuel sources from recycled spent oxide fuel.oxide fuels with the as recycled amountwith historical expectations. The axial of carry over contaminates. This workgrowth for all the three IRT1 rodlets was supports reduction of potential wastehigher compared to the literature for created by current and future light waterU-20Pu-10Zr EBR-II pins at this burnup; reactors making the nuclear fuel cyclethe reason for this is not known. safer and more economically competi- Gamma ray spectrometry of the rodlets tive. The successful irradiation of theshowed behavior of gamma emitting IRT-1 test has shown initial feasibilityfission products which followed trends of a recycled oxide fuel cycle. This workhistorically observed for a solid, sodium can be continued by irradiation of thebonded fuel.IRT-2 test and by continuing irradiationThe fission gas release results for IRT-R2 of remaining IRT-1 samples not used forof ~7010%, is in good agreement destructive examination. with historical norms for 75% smeared Accomplishments: density U Pu Zr (or U-10Zr) fuel Luca Capriotti performed the PIE onbehavior beyond ~3 atom % burnup. IRT1-C1, C2, and C5. Non-destructiveHowever, for IRT-R1 and -R5 the fission PIE results consist of visual exams,gas release was lower, around 32-36%. neutron radiography, dimensionalThis may be related to a slightly lower inspection, and gamma-ray spectrom- calculated burnup of the two rodlets, etry. Destructive PIE results consist ofthe possibility that the porosity is still fission gas analysis, optical microscopynot fully interconnected, and the smear of the fuel, and electron microscopy of adensity of these rodlets was around fuel and cladding section.79%. Fuel metallography for IRT-R1 Visual examination showed no obviousand -R5 did not show a microstructure defects in the rodlets, although, somedeveloped entirely as it would be discoloration was noticed in the fuelexpected for metallic fuel at the same region. Neutron radiography imagesburnup and irradiation temperature, were taken of the capsules and rodlets,seen in Figure 2. Metallography of shown in Figure 1. Overall, the rodletsIRT-R2 presented a microstructureFigure 2. Optical microscopy of the fuel appear to have behaved well, in linewhere at least 3 regions could be seen,a) IRT1-R1 b) IRT1-R2, and c) IRT-R32021|AFC ACCOMPLISHMENTS 133'