2018 | AFC ACCOMPLISHMENTS 94 The results inform the design of the future in-pile experiments in the TREAT reactor.Thus, the out-of-pile transient testing capability is a vital tool for selecting ATF candidates to advance nuclear fuel safety. Accomplishments: The novel optical metrology technique was successfully applied to the pulse- controlled MBT as shown in Figure 1. The 360° view of the tube sample was tracked during the PCMI tests using a high-speed camera, a telecentric lens, and heat-resistant first-surface mirrors (Figure 1a-b).The working principle of MBT is depicted in Figure 1c: a projectile (core-pin) is actuated to move within the hydraulic oil-filled cavity of the driver tube. Motion of the core-pin causes pressurization of the hydraulic oil, triggering expansion of the driver tube, which imposed mechanical strain on the sample. This type of loading simulates the strain-driven nature of PCMI during postulated RIA. Figure 2. The pressurization rate dependence of the failure strain of SiC/SiC composites tested with MBT. Failure strains were calculated using DIC methods from speckle-painted surfaces of the tube samples.