1 / 21

Cook Nuclear Plant Experience with Storm Water Tritium Discharges

Cook Nuclear Plant Experience with Storm Water Tritium Discharges. Jason T. Harris Purdue University/NATC David W. Miller UIUC/NATC/Cook NP Terry Brown RPM, Cook NP. Discovery. May 30, 2007 Cook Nuclear Plant staff detected tritium on-site

briana
Download Presentation

Cook Nuclear Plant Experience with Storm Water Tritium Discharges

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cook Nuclear Plant Experience with Storm Water Tritium Discharges Jason T. Harris Purdue University/NATC David W. Miller UIUC/NATC/Cook NP Terry Brown RPM, Cook NP 17th Annual RETS-REMP Workshop Philadelphia, PA June 25-27, 2007

  2. Discovery • May 30, 2007 Cook Nuclear Plant staff detected tritium on-site • Led to increased sampling of various locations on site including wells and outfalls • Ground water wells did not indicate the presence of tritium • Initial North Storm Drain Outfall to beach sample found to contain tritium at 5540 pCi/L • Subsequent samples ranged from 2300-8870 pCi/L • South outfall samples <LLD • North outfall catch basins sampled (5000-17000 pCI/L) • Condensate from air conditioning units (4500-16000 pCi/L)

  3. Initial Steps • Early June – notifications were made to several stakeholders (NRC, NEI, INPO, government) • North outfall re-directed back into plant to the turbine room sump (monitored release path to the absorption pond) • Sampling protocol set up for north and south outfalls, and turbine room sump and absorption pond • Supporting/refuting analysis developed to validate hypothesis that the source of elevated tritium levels is from downwash and air conditioning condensate • Evaluation of initial leak continues

  4. Initial Storm Drain Sample Locations North Outfall N

  5. Initial AC Condensate Sample Locations RPAC Security OBA N

  6. Tritium Samples for Split Analysis

  7. Initial Rain Gauge Locations TSOC Brass Shack Guard House Visitor N

  8. Early Results • Constant sampling showed that tritium found only in samples north of Unit 1 • “plume” of tritium migrated from plant and up service road • AC condensate and North Outfall continued to show presence of tritium

  9. North Outfall Tritium

  10. Pathway Hypotheses • By early June, two pathways were verified and identified by sampling to be the probable sources of tritium • Condensate from the air conditioning units in the Radiation Protection Building located immediately adjacent to containment release points for Units 1 & 2, North Security Guardhouse and Administrative Office Buildings (including annexes). • Downwash from the station vents located at the top of each containment building during rainfall episodes.

  11. Additional Rain Gauges • An additional 28 rain gauges (32 total) were placed throughout the site • Collections revealed similar patterns (tritium in prevailing wind samples N-NW) • Positive samples • Guard house lawn • Unit 1 and 2 roof vents • RPAC

  12. Current Rain Gauge Locations N

  13. Current Rain Fall Locations Control

  14. Dose Consequences • Initial dose analysis performed on three highest tritium concentration samples • Assumed 24 hour release @ 1000 gal w/ 230,000 gpm dilution • REMP pathways also assessed at highest annual Χ/Q (insignificant) • Max = vegetation, 3.30 E-08 • 10 CFR 50 results • Max = particulates, 6.76 E-08

  15. Dose Consequences

  16. Current Progress • Continuing to monitor, sample, and test rain gauges (and ac condensate) • Study impact of humidity and rainfall amount • Investigating building freezer ice (David Miller) • Categorize site throughout the year (wind changes, humidity, etc.)

  17. Conclusions • Air conditioning condensate and rainfall contributing to outfall tritium • Tritium levels in rainfall downwash are influenced primarily by 2 factors • Prevailing wind direction • Amount of rainfall • For Cook (sandy soil), water percolating to Lake Michigan through monitored pathways • To best categorize site, need several rainfalls throughout the year (different prevailing winds)

  18. Additional Areas of Investigation • Evaluate sublimation as it relates to hydrogen/tritium water evaporation rates • Maintain spent fuel water at higher temperature in winter (when drier) for better evaporation (and use large surface area, like roof, for evaporation • Longer rain event more important than short thunderstorms for seeing tritium • For irrigation purposes – trickle underground to avoid standing water that may show increased tritium levels

  19. Additional Areas of Investigation • Don’t release in rain event • Sites with single gaseous release points 2.5 x highest structure/elevated release (e.g., LaSalle and Browns Ferry) –aren’t seeing this phenomenon • Purchase more land

  20. Acknowledgements • Cook Tritium Investigation Team • John Harner, Lead • Dave Faulkner, Chemistry • Bill Hannah, Maintenance • Walt McCrory, Engineering • Doug Foster, Environmental • Joe Beer, RP

  21. Questions? Thank You! 17th Annual RETS-REMP Workshop Philadelphia, PA June 25-27, 2007

More Related