b'Figure 1. A unique autoclave fretting-impact rig (AFIR) at ORNL. (top-left) The AFIR control unit, power supply, and plumbing; (top-right) The furnace and test chamber behind the panels; (bottom-left) The autoclave vessel with liquid and gas handling system; (bottom-right) The specimen assembly inside the autoclave chamber.environment in Westinghouse Electricand 100 hours (AFIR-L). Figure 3 Company (WEC)s VIPER system, a full- compares the appearance of claddings assembly reactor core simulator. AFIRand their respective grids after 20 and tests were carried out at 204 C under100 hour fretting tests in pressurized a pressure of 20-23 bars. The contactwater at 204 C. The conventional force between a pair of cladding- Zr-Zr pair showed a darker color after dimple was 0.50.1 N, matching thethe 100-hr test due to a significant peak cladding-dimple force of 0.5 Nincrease in oxidization during the in reactor [8]. The fretting frequencylonger test, as expected. In contrast, was set at 25 Hz and the oscillationthe Cr-coated cladding had little stroke was 7510 m. Testing waschange in appearance after the 100-hr carried out at both 20.5 hours (AFIR-S)test, which is indicative of superior 2020|AFC ACCOMPLISHMENTS 67'