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
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. Background . - PowerPoint PPT Presentation
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Control Selection Techniques Employed for D&D Projects with Emphasis on Nuclear Criticality Safety Controls
Brenda L. HawksEngineering Director
Oak Ridge Office of Environmental ManagementJeff Castor
Criticality Safety Engineer, Navarro Research and Engineering
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Background 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 unreliableExample: 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
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Background 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 environmentExample: 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
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TRU Waste Processing Center (TWPC) 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
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TRU Waste Processing Center (TWPC) 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
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ORNL Facilities/Hot Cells D&D 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)
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ORNL Facilities/Hot Cells D&D However, there are differences during D&D activities as
compared to static facility conditions:Discovery of previously unknown quantities of fissionable
material are possibleEquipment with potential holdup collected together in waste
containers Also, ANSI standard subcritical limits are water based, and
are not always appropriate during D&D activitiesWill D&D involve organic cleaning of equipment/piping?Will waste containers be grouted to meet disposal requirements?
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ORNL Facilities/Hot Cells D&D Therefore, a minimal NCS Program is established, including
availability of a knowledgeable NCS engineer to identify and resolve potential concerns as D&D progressesNCS 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
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K-25 GDP D&D Operations involving significant quantities/forms of
fissionable material typically require certified Fissile Material Handlers per DOE O 426.2 (previously 5480.20A)
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)
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Criticality Safety Officer (CSO) position/program provides enhanced NCS knowledge in the field.CSOs have a strong field presence with operations crewsCSOs knowledgeable of NCS requirements and controlsGood 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 426.2 describes CSO position/program and provides qualification requirements
K-25 GDP D&D
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Conclusion
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