b'A dense Cr-coating on a zirconium- showed a significant increase in thermal based cladding substrate has theconductivity compared to UO 2 . As part potential for improved high temperatureof the proof-of-concept, investigation steam oxidation resistance and highhas been focused on understanding temperature creep performance, as wellevolution of thermal conductivity and as improved wear behavior. Over themicrostructure under irradiation.course of the EATF program, exten- For revolutionary performance sive processing and testing activitiesimprovements, Framatome is devel-are being carried out on Cr-coatedoping a composite cladding comprised M5 Framatomecladding in support of batchof SiC fiber in an SiC matrix (SiCf/SiC) implementation by the mid-2020s. as well as studying applications for Building on both the experienceother critical components such as BWR gained and scientific knowledgechannel boxes and structural tubes. The achieved from the PWR Cr-coatedobjective is to develop a fuel system cladding development, a coating mate- which does not suffer from the same rial that is suitable for BWR applica- rapid oxidation kinetics of zirconium-tion has been developed. Severalbased cladding while having attractive out-of-piles tests were performed tooperating features.ensure adherence and coating quality.Accomplishments:Currently, the lead test rods with BWROnsite visual inspections were coating segments are being irradiatedperformed on Cr-coated Lead Test Rods in the Monticello reactor. (LTRs) after first cycle irradiation in Chromia-doped UO 2pellets canVogtle Unit-2.The Cr coating was very improve pellet wash-out behavior afteradherent to the underlying M5 Framatome Figure 2. Cr-Cr LTA at Calvert Cliffscladding breach and reduce fission gascladding with no signs of coating release. The performance of this fuel hasdelamination. Cr-coated rods showed been extensively studied in out-of-pilelustrous-gold appearance suggesting and in-pile test programs. Chromia- that the oxide formed on the surface doped fuel topical report for PWRof the cladding was very thin (Figure application has been submitted to the1). These results confirm the excellent Nuclear Regulatory Commission (NRC)performance of the Cr-coated cladding in June 2021. which was demonstrated in the out-of-Framatomes EATF pellet developmentpile tests and other in-pile programs. is also focused on improving thermal- Similar performance was observed mechanical properties, especiallyfor both inert and UO 2fuel loaded thermal conductivity. Variants ofCr-coated rods, which completed one Cr-doped UO 2fuel pellets have beencycle at Arkansas Nuclear One (ANO) developed and out-of-pile testingin April 2021 and in GOCHROM 2021|AFC ACCOMPLISHMENTS 87'