17 th Annual RETS-REMP Workshop Philadelphia, PA June 25-27, 2007 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

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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 pCi/L  South outfall samples <LLD  North outfall catch basins sampled ( pCI/L)  Condensate from air conditioning units ( pCi/L)

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Initial Storm Drain Sample Locations North Outfall N

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Initial AC Condensate Sample Locations RPAC OBA Security N

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Tritium Samples for Split Analysis Tritium Samples For Split Analysis Sample Tritium Gamma AnalysisArevaKinectrics LocationDate / Timepicocuries/literuci/ccvolume North Outfall 5/31/07 16:418060ND100 mls RPAC AC Unit Condensate6/1/07 13: ND30 mls OBA A/C Condensate (Short Hose)6/1/07 14: ND100 mls 2 ESW Pipe Tunnel6/2/07 8:103460ND100 mls Security Building AC Condensate6/2/07 15: ND100 mls

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Initial Rain Gauge Locations TSOC Visitor Guard House Brass Shack N

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 North Outfall Tritium

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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.

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Current Rain Gauge Locations N

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Current Rain Fall Locations Control

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Dose Consequences Initial dose analysis performed on three highest tritium concentration samples Assumed 24 hour 1000 gal w/ 230,000 gpm dilution REMP pathways also assessed at highest annual Χ/Q (insignificant)  Max = vegetation, 3.30 E CFR 50 results  Max = particulates, 6.76 E-08

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Maximum Individual Doses Sample LocationEffluentApplicable Estimated DosePeakLocation % ApplicableLimit OrganmRem Age Group LimitmRem Security Building AC Condensate pCi/LLiquidT. Body5.34 E-09ChildReceptor3.56 E E+00 LiquidLiver5.34 E-09ChildReceptor1.07 E E+00 RPAC AC Unit Condensate pCi/LLiquidT. Body4.67 E-09ChildReceptor3.11 E E+00 LiquidLiver4.67 E-09ChildReceptor9.34 E E+00 OBA A/C Condensate (Short Hose) pCi/LLiquidT. Body3.67 E-09ChildReceptor2.45 E E+00 LiquidLiver3.67 E-09ChildReceptor7.34 E E+00 Dose Consequences

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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.)

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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)

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 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

16 th Annual RETS-REMP Workshop Mashantucket, CT June 26-28, 2006 Acknowledgements Cook Tritium Investigation Team  John Harner, Lead  Dave Faulkner, Chemistry  Bill Hannah, Maintenance  Walt McCrory, Engineering Doug Foster, Environmental Joe Beer, RP

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