Guided waves and robots advancing inspection of areas with limited access
Nuclear power plant containment vessels have large, inaccessible regions that cannot be inspected by conventional techniques. Inaccessible regions often are encased in concrete, soil or sand, or hidden behind equipment attached to a wall. Similar constraints affect the inspection of double-shell tanks designed to store nuclear waste, illustrated in Figure 1, that have an inaccessible region at the tank bottom where the primary shell is supported by the secondary shell. Present methods to monitor the integrity of these vessels primarily rely on partial inspections of accessible areas or estimation of corrosion rates; however, these approaches cannot account for nonuniform localized corrosion or cracking.