Decontamination Techniques and Fixative Coatings Evaluated in the Building 235-F Legacy Source Term Removal Study

Savannah River Site Building 235-F was being considered for future plutonium storage and stabilization missions but the Defense Nuclear Facilities Safety Board (DNFSB) noted that large quantities of Plutonium-238 left in cells and gloveboxes from previous operations posed a potential hazard to both the existing and future workforce. This material resulted from the manufacture of Pu-238 heat sources used by the NASA space program to generate electricity for deep space exploration satellites. A multi-disciplinary team was assembled to propose a cost- effective solution to mitigate this legacy source term which would facilitate future DOE plutonium storage activities in 235-F. One aspect of this study involved an evaluation of commercially available radiological decontamination techniques to remove the legacy Pu-238 and fixative coatings that could stabilize any residual Pu-238 following decontamination activities. Four chemical methods were identified as most likely to meet decontamination objectives for this project and are discussed in detail. Short and long term fixatives will be reviewed with particular attention to the potential radiation damage caused by Pu-238, which has a high specific activity and would be expected to cause significant radiation damage to any coating applied. Encapsulants that were considered to mitigate the legacy Pu-238 will also be reviewed