b'Figure 2. Data from the the first flexural mode of the canti- behavior in-reactor, making this test RUSL copper beam irradiationlever. A second fiber, near the tip of theideal for demonstrating whether the performed in TREAT. beam, measures oscillations in lightmethod was viable in the presence reflected from its surface (due to beamof neutron/gamma bombardment. defocusing/deflection) to determinePreliminary data analysis shows good displacement so that changes can besimilarity between the in-pile and monitored by measuring the resonantout-of-pile data. frequency. Such an approach is idealLastly, the Characterization-scale in TREAT where total radiation dose isInstrumented Neutron Dose typically low enough to avoid dark- Irradiation (CINDI) module design ening of optical fibers. The first RUSLwas completed, underwent final irradiation was performed in TREATdesign review, and is now under in mid-2018 using a small copperfinal fabrication to prepare it for specimen so that in-reactor data couldirradiation. CINDI consists of a be compared to out-of-pile testsfew Swagelokcapsules, each which had previously been performedwith thermocouple temperature in a lab furnace (where the recrystalli- monitoring and the ability to house zation behavior is caused by tempera- several 5mm diameter disk-like ture alone). The specimens fastspecimens, arranged in a vertical neutron damage rate was predictedhanging structure for elevated to be inadequate to cause differenttemperature irradiation within the 206 2019|AFC ACCOMPLISHMENTS'