Control Selection Techniques Employed for D&D Projects with Emphasis on Nuclear Criticality Safety Controls Brenda L. Hawks Engineering Director Oak Ridge Office of Environmental Management Jeff Castor Criticality Safety Engineer, Navarro Research and Engineering

- 2 -  Hazards during D&D are often different than hazards present in an operating facility  During D&D, a facility will, by definition, be undergoing significant physical changes that often render engineered safety features ineffective and/or unreliable  Example: safe geometry aspect of small diameter piping is lost when piping is dismantled and collected together (in a waste box for disposal, or on a pallet on the ground, etc.)  D&D environment is dynamic. Tasks are typically non- routine, non-repetitive

- 3 -  In developing an appropriate control set for D&D activities, differences in the types of hazards and the effectiveness/reliability of engineered safety features must be considered  Risk can often be managed effectively via administrative controls in a D&D environment  Example: Rather than upgrade the sprinkler system in a facility undergoing D&D, the fire hazard/risk can be managed by implementing a more robust combustible control program, fire watch requirements, etc. By doing so, D&D can continue to remove MAR and eliminate the hazard altogether, rather than waiting until the sprinkler system upgrades can be completed

- 4 -  Supports D&D of other facilities (e.g., K-25, other ETTP site facilities)  Waste containers (drums, boxes) received, repackaged and characterized for transportation and disposal compliance  NCS achieved by strict adherence to very low fissionable mass levels  In each individual container  In each repackaging area  Container/area fissionable mass controls selected as TSR controls

- 5 -  With very low fissionable masses, a “graded” NCS program was approved by DOE  Determined to be more cost effective (with no increase in overall risk) to operate at very low fissionable masses than to develop a full-blown NCS program

- 6 -  Facilities characterized and documented as low NCS concern during static conditions (limited quantities of fissionable material, no activities conducted) under previous contractor with full NCS program  D&D to be performed by small contractor with no NCS staff  Tendency is to use ANSI standard subcritical mass limits and claim no NCS Program needed (i.e., entire facility inventory is less than the ANSI standard subcritical mass limit for the isotope of concern)

- 7 -  However, there are differences during D&D activities as compared to static facility conditions:  Discovery of previously unknown quantities of fissionable material are possible  Equipment with potential holdup collected together in waste containers  Also, ANSI standard subcritical limits are water based, and are not always appropriate during D&D activities  Will D&D involve organic cleaning of equipment/piping?  Will waste containers be grouted to meet disposal requirements?

- 8 -  Therefore, a minimal NCS Program is established, including availability of a knowledgeable NCS engineer to identify and resolve potential concerns as D&D progresses  NCS Program strongly credits facility inventory control program (no addition of fissionable materials to facilities with exception of limited, small quantity sources) and anomaly detection program (to ensure NCS engineer involvement in discovery of previously unknown fissionable material items/materials)  Facility inventory control program and anomaly detection program both elevated as programmatic controls under the Hazardous Material Protection Program in the safety basis documents

- 9 -  Operations involving significant quantities/forms of fissionable material typically require certified Fissile Material Handlers per DOE O (previously A)  In a D&D environment, maintaining staff of certified Fissile Material Handlers is difficult due to type of work being conducted (dismantlement, deconstruction activities as opposed to material processing activities)

 Criticality Safety Officer (CSO) position/program provides enhanced NCS knowledge in the field.  CSOs have a strong field presence with operations crews  CSOs knowledgeable of NCS requirements and controls  Good interface with both operations personnel and NCS engineers (who also have significant field presence)  CSO Program required as part of NCS Safety Management Program discussed in safety basis document, and in the DOE- approved NCS Program Description document  Training Implementation Matrix developed per DOE O describes CSO position/program and provides qualification requirements

 Risk can often be managed in a D&D environment utilizing a combination of administrative and programmatic controls in lieu of engineered controls, at reduced cost and with no increase in overall risk