149 Proactive Hazard Management of Deactivation and Decommissioning at a DOE Nuclear Facility (PSAM-0366)

As hazardous facilities reach end of life, the level of attention needed during the period of time they are being retired is a safety management issue. This is particularly true if there is significant regulatory burden associated with the facility. The objective of the work reported here is to describe how to make risk based decisions regarding safety management as activities required to retire the facility take place.

An example is provided in this paper for one US Department of Energy nuclear facility that proactively applied DOE's hazard categorization method during projected stages of Deactivation and Decommissioning (D&D). Hazard categorization is required to be performed for all DOE nuclear facilities. The hazard category level determines the level of potential risk from radioactive materials in the facility. Lower hazard category release the facility from certain regulatory requirements.

The results at the DOE facility are being used to improve safety management at the facility by providing insights about whether re-sequencing or modifying D&D activities that affect the radioactive inventory would be of benefit. This paper presents the methodology used to perform this proactive assessment and provides examples from application at a spent nuclear fuel basin at Hanford. The DOE has oversight and regulatory authority over several post war legacy nuclear facilities at the Hanford Site in Richland Washington as well other sites across the U.S.

The assessment consisted of determining the hazard categorization of a number of facility states that could exist in the time frame in which D&D is performed. A sequence of “facility states” states were defined and hazard categorization projected for each state. This proactive hazard assessment determination showed the point at which one of the basin facilities could reduce its nuclear safety status and corresponding regulatory burden. It also provided insights about how to accelerate that de-categorization.

By proactively projecting into the future about inherent risk from a facility undergoing D&D A case can be made for relaxing safety controls as D&D incrementally reduces the risk in situations where the risk is mostly related to hazardous material inventory.