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This article discusses the hazard classification of the Remote Handled Low-Level Waste Disposal Facility at the Idaho National Laboratory. It explores the facilities generating RH-LLW, alternative disposal options, waste streams, and the concept of hazard categorization. The conclusion emphasizes that downgrading the hazard classification does not provide significant cost savings and may limit future operations.
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Hazard Classification of the Remote Handled Low-Level Waste Disposal Facility Boyd D. Christensen Battelle Energy Alliance, Idaho National Laboratory P.O. Box 1625 Idaho Falls, Idaho 83415 208-526-7914 boyd.christensen@inl.gov May 9 2012
Remote Handled Low Level Waste Disposal at INL • The INL consists of a number of different research complexes conducting science and engineering solutions to nuclear energy development programs • Many of these programs generate RH LLW. • Current disposal is at the Radioactive Waste Management Complex (RWMC) on the INL site. • RWMC is scheduled for closure within the next 3-5 years
INL Facilities Generating RH LLW • Materials and Fuels Complex (MFC) • Hot Fuels Examination Facility • Fuel Conditioning Facility • Analytical Laboratory • EBR-II Legacy waste in temporary storage • Advanced Test Reactor (ATR) • Reactor component hardware • Reactor system resin beds • Naval Reactor Facility (NRF) Expended Core Facility • Reactor component hardware • Reactor system resin beds
Alternatives for RH LLW Disposal • Nevada National Security Site – smaller cask, more shipments (>100/yr), 1420 miles r/t, 25000 population along travel corridor, greater risk • Commercial disposal facility – program risks • INL RH LLW disposal Facility** - “out of commerce” transportation, use of existing cask systems, no population, lower risk • No action – INL R&D mission impact, national security impact **Highest ranked alternative for INL RH LLW disposal
Waste Streams • LLW solids • <100 nCi/g TRU elements • > 200 mrem/hr • Anticipate up to 60,000 R/hr • <15 g fissionable material per disposal vault • No liquids allowed • Waste packaged in SS canisters in generating facilities then transferred by shielded cask to disposal facility
Facility Hazard Categorization • Following DOE-STD-1027, preliminary HC based on entire facility inventory (only modification is exemption of sealed sources meeting specific criteria) • Final HC can be performed considering 1) alternate release fractions and 2) change in material subject to an accident due to facility features that preclude bringing material together or causing harmful interaction from a common severe phenomenon(facility segmentation)
Preliminary Hazard Categorization • Simple screening step to identify likely hazard category • Consideration of form, location, dispersibility, and interaction with energy sources are not given • Sealed sources may be exempt from inventory for HC; fissile material in sealed sources not excluded • Special form criteria; DOT, NRC, ANSI
Final Hazard Categorization • Modification of TQs • Alternate release fractions used for “obvious gross inconsistency” • Potential to increase HC based on higher dispersible form or interaction with energy source • Facility Segmentation (2 cases) • A multiple structure facility – physically separated structures (example: multiple storage bunkers with one common safety basis [one facility]) • A single but segmented facility – internally divided into non-interacting segments
Hazard Categorization for RH-LLW Disposal Facility • Preliminary HC; HC-2 nuclear facility – based on total facility inventory • Final HC; consideration for facility segmentation results in HC-3 sum of fractions
Is Lower HC Better? • What are benefits of adjusting (lowering) HC? • Simpler safety basis development • What are the risks associated with lowering HC? • Risk of exceeding TQs if HC-3 • May limit future operations and waste streams
Conclusion • For the RH-LLW disposal facility at INL no significant cost savings in downgrading HC • Does not change the facility Performance Category or QA requirements (SDC drives design) • No real benefit or advantage (but some added risk) identified for downgrading HC • Initial HC-2 classification to remain in effect