Radiation safety aspects of a hot-cell decontamination

Extensive decontamination was conducted to prepare the interior of the argon cell at the Hot Fuel Examination Facility for refurbishment. The radiation field associated with 10-16 yr-old fission products was reduced by remote cleaning before personnel entry. This paper describes the operations, dosimetry, protective clothing, hardware and procedures used to ensure compliance with radiation exposure guidelines. Contact decontamination was conducted in general radiation levels that varied from 300 to less than 30 mrem/hr for that component of the radiation that could penetrate 540 mg per cm2 of aluminum. However, it was the nonpenetrating component that controlled in-cell stay times; it varied from 1500 to less than 130 mrem/hr. Even after decontamination, several areas of fixed contamination emitting over 1000 mrem/hr of nonpenetrating radiation were identified and locally shielded. There were 916 person-entries required for decontamination. These resulted in integrated exposures of 99 and 599 man-rem for the whole body and skin, respectively.