b'these investigations did not reveal a brittle Laves phase. Nanoindentation maps between coating and cladding material, displayed in Figure 2, were utilized to determine hardness and elastic modulus across the interface are necessary parameters for future simu-lations. Coatings were first attempted on the as-received cladding surfaces, but it was determined that the surface roughness of the pilgered tubes was too high to achieve continuously adhered coatings. Coated tubes containing surface defects were used to test the potential impact of a cracks in the Cr shell using modified burst tests (MBTs) to simulate reactivity-initiated accidents (RIA) and burst tests in the severe accident test station at ORNL to simulate LOCA. Digital image correla-tion and a mirror setup was used during MBT to measure the strain on the entire circumference of one tube specimen as shown by the four projections on the same specimen in Figure 3. It was found that both the coated and uncoated material did not burst at hoop strains up to and above 8% at room temperature and at 275C. Furthermore, at the plane strain state, the coated material did not burst at a hoop strain of 6%. For LOCA perfor-mance, it was found that the uncoated and coated material both followed the historical Cathcart-Pawel relation for burst temperature vs. hoop stress as shown in Figure 4. Cracked coatings have not shown a negative impact on the base properties of cladding during those tests.Figure 3. MBT hoop strain measurements using DIC for uncoated and coated Zircaloy-4 at room temperature2021|AFC ACCOMPLISHMENTS 65'