Novel Monitoring of Physically-Difficult-to-Access Safeguarded Systems via
Autonomous Self-Propagating Space-Filling Chemical Waves

The sensing of stimuli including changes or perturbations in spatial and chemical properties is an important operation in monitoring of Safeguarded systems that may be hazardous or impossible to access using conventional remote sensing, sensors, and/or information transmission systems. For example, in chemically reactive or radioactive environments, sensor life may be severely limited due to heat, corrosion, and/or radiation degradation. In other examples, it may be impractical to place sensors and/or transmit information from remote locations simply due to inaccessibility in systems that require sealed containment or inherently have confined spaces such as spent fuel storage facilities or geologic waste repositories. We discuss sensing, analysis, and information transmission using chemical systems with autocatalysis and chemical wave behavior that are used as geospatial environmental sensors and information transmitters. These systems can operate remotely, react to environmental stimuli, and propagate information over large distances, including out of physicallydifficult-to-access areas. Application examples include perturbation detection of containment systems such as dry storage canister breaching and detecting changes in fracture network geometries surrounding subsurface repository excavations. The chemical wave sensor systems and methods are applicable in both aqueous and gaseous phases. Computational fluid dynamics simulations including radiolytic and photolytic reactions coupled to transport reveal benefits such as amplifying and/or propagating signals from radiation by-products to where measurements could be made. We report on new benchtop experiments to validate the tuning of traveling chemical waves for sensing radiation by-production over long distances (e.g., > 1 m).