Postirradiation Examination of the ATF-1 Experiments - 2018 Status

Abstract

A collaborative effort of the Advanced Fuels Campaign together with industry consortia is focused on the development of enhanced Accident Tolerant Fuels (ATF) for Light Water Reactors (LWRs). The scoping studies, referred to as ATF-1 irradiations, are being performed in the Advanced Test Reactor of Idaho National Laboratory using drop-in style irradiations. The Post-Irradiation Examinations (PIEs) of ATF-1 began in 2017 and continued in 2019. This report describes the results of examinations on ATF-1 irradiations designed to test the performance of advanced iron-based cladding, including compatibility of FeCrAl with UO 2 , and ATF-1 irradiation of U 3 Si 5 .

Non-destructive Examinations of ATF-2 Baseline Rodlets

“…Gamma spectrometry of the rodlets was performed using the HFEF Precision Gamma Scanner (PGS). Details about the system have been reported in other PIE reports [3,4]. The results of some of the principal gamma emitters generally used as burnup monitors are shown in Figure 8a through Figure 8g for each of the rodlets.…”

Post-Irradiation Examinations of the ATF Experiments - 2020 Status

“…For each of them, the same measurement protocols used previously for the other ATF PIE have been followed. Details of each of the experimental techniques used can be found in the previous PIE reports [10,11].…”

Solid-state phase transitions of two quaternary metallic fuel alloys (U-2.5Mo-2.5Ti-5.0Zr and U-1.5Mo-1.5Ti-7.0Zr in wt. %)

“…Some preliminary investigations have been performed on the 90.0U-5.0Mo-4.3Ti-0.7Zr (wt. %) alloy [2,5,11,12]. Constituent redistribution was not observed in this alloy, but there was significant fuel-cladding chemical interaction (FCCI) during irradiation, primarily due to the low Zr content and high Mo content.…”

“…By combining these systems, the advantages can potentially be maintained while minimizing the disadvantages. Mariani proposed an alloy containing Mo, Zr, Ti with U (or quaternary UMTZ alloy) [3,4], with the expectation of decreasing the  phase onset temperature (by Mo) and increasing the solidus/liquidus temperatures (by Zr and Ti) over that of pure uranium [3,4,5]. A low γ phase onset temperature will be beneficial due to the isotropic swelling in this cubic phase [4,6].…”