Radiation Field Characterization using Autonomous Robots

Nuclear facilities contaminated with radioactive materials pose serious challenges for the agencies and workers tasked with their monitoring and decommissioning. Facilities such as the Hanford Site in Washington State were left contaminated with waste and byproducts of plutonium production following the development of nuclear weapons during the cold war, which will require decades of cleanup activity to mitigate. Such tasks frequently expose workers to the unseen hazards of gamma radiation, therefore the development of radiation intensity maps of contaminated environments can guide workers to safe areas and identify radiological risks in an environment. This work presents two methods for radiation monitoring which produce contamination maps of the area of deployment. The first method is capable of localizing a single radiation source with a minimal number of measurements, thereby operating within the constraints of an aerial robotic platform as well as the challenges posed by radiation field characterization. The second method enables distributed radiation field mapping in more complex environments where radiation sources cannot be approximated by a single point in space. The challenges of radiation field characterization are presented, followed by a description of the methods and systems developed. Finally the methods are demonstrated in simulation as well as in field experiments in which actual radiation sources are deployed, localized, and mapped successfully