ANALYSIS OF AS-MACHINED NUCLEAR GRAPHITE PARTS USING CONVENTIONAL AND LASER ULTRASONIC TECHNIQUES

The feasibility of remote, in-service monitoring of as-machined nuclear graphite parts using noncontacting laser ultrasonics was investigated. The anisotropy sensitivities of laser ultrasonics and several other conventional techniques were compared for three significantly different nuclear-grade graphites. Laser ultrasonics using a Fabry-Perot interferometer proved sufficiently sensitive to detect the anisotropy in a bulk graphite having moderate grain size. In contrast, a coarse-grained graphite was difficult or impossible to investigate using any of the techniques. Laser ultrasonic monitoring of some graphites may be useful in future nuclear operations, particularly for in-service applications where contacting and destructive analyses are unsuitable.