Development of Remotely Controlled Devices for Three Mile Island Unit 2

The postaccident Three Mile Island Unit 2 (TMI-2) plant was a maze of contaminated areas with varying levels of radiation. Several cubicles in the auxiliary building could not be entered for survey, much less to decontaminate. The containment basement was the most contaminated region with radiation fields up to 1100 R/h. The thousands of curies of cesium and strontium contained in the loose debris, sediment, and water made the basement a difficult region to decontaminate. To characterize and decontaminate these hazardous areas, cleanup personnel were forced to consider the use of remotely controlled (robotic) equipment. The remote equipment program at TMI-2, driven by need, resulted in considerable reduction of radiation exposure to plant personnel. The remotely operated devices developed under this program and the general criteria formulated for each design are described.