ML090500105

Entergy Document-GW Investigation Gov'T to Gov'T Meeting

ML090500105
Person / Time
Site:	Indian Point
Issue date:	01/31/2008
From:	Mayer D Entergy Nuclear Northeast
To:	NRC Region 1
References
Download: ML090500105 (20)

Text

7G:unv eIs Don Mayer Indian Point Energy Center.

Director Unit 1

. , 9, .1! , ,

Ground Water Investigation Overview 4 Chronology E .Identification of Sources

• Impact Assessment of Leaks 4 Hydrological Site Model

• Calculation of Potential Exposu re to Public

• Remediation Strategy

• Conclusions

ndia-n Point Looking South Along the, Hudson River

Overhead View of Indian Point

• • ~&~

BB

• J Identify Sources of Contamination IP2 Spent Fuel Pool Hairline concrete shrinkage cracks identified in Fuel Storage Building wall during 2005 excavation for new gantry crane Water collected determined to be of fuel pool origin

• Tested existing wells on site for radioactivity- Tritium detected in the IP2 transformer yard

" Tested off-site wells and water supplies for radioactivity-none detected >BG

" Accessible pool walt areas inspected

" Pinhole defect was identified and repaired in the Fall of 2007

Unit 2 Spent Fuel Pool, Layout II II A

Ij Crane Truck Bay Collection Box

Identify Sources of Contamination Collection Device " Unit 2

• Collection device installed to capture water seeping from waLL crack

• Volume of water has

• • ecreased to essentially zCot Collec-tion box

1P2 Spent Fuel Pool Liner Inspection

• inspected accessible portions of liner -- _-------

with divers and remote video camera (2005-2006), including previously repaired 1992 damage area.

• No leaks detected using visual and vacuum box testing techniques,

• Decision made to conduct extensive transfer canal inspections as extension of pool liner

• Ability to drain and inspect allows even more extensive evaluation for potential degradation mechanisms

1P2 Transfer Canal Inspection Transfer Canal Inspections

• Evaporation Test e Microbiologically Influenced Corrosion (MIC) test

• Drained and inspected for bleed back o Inspected over 730 linear feet of welds Non destructive evaluations

• Visual o Vacuum box 0 Ultrasonic testing Identified 1 through-wall "pinhole" leak

• Repaired November 2007 Did not identify any degradationmechanisms for pool or transfercanal liner (Key finding)

I....................................................

Leak Source Conclusions Source of the leaks

• Unit 2 Spent Fuel Pool

• 1990-1992 leak in liner, which while repaired, resulted in residual local tritium under the pool that contributes to observed ground water concentrations

• a pinhole defect in the transfer canal which has been repaired

• Unit 1 Spent Fuel Pool

• Legacy leak which is presently being mitigated with demineralization/filtration technology. This is the source of Sr-90 observed in monitoring wells

• Source effected areas are fully characterized by monitoring wells and the site hydrological model.

Assessment of Impacts

• Installed over 40 multi-level I

J monitoring wells in three phases

• Developed hydrological model which maps ground water flow and contaminant migration Sampled storm drains, river sediment, and fish

• Examined drain systems and other potential conduits of water flow-

• Monitored boundaries and riverfront Calculated potential dose to public

tz 110- 120 HUDSON RIVER ELEV. = 1.5' Xt - 100 S80--DO p -so 40 - 511 20- 30 10 -20

Tritium Map Tritium migration from Unit 2 Pool leakage.

Minor contribution from Unit 1 Circles indicate monitoring well placement Concentration drops toward river Plume diluted to non detect at river

Sr-90 Map Strontium migration from Unit 1 Pool leakage.

Circles indicate monitoring well placement Concentration drops toward river Plume diluted to non detect at river Legacy contamination from old Unit 1 piping east of Unit 3

Remediation Strategy Unit 1 UStop Pool Leakage

• Leak source elimination by removal of IPI spent fuel from pool, Complete Fall 2008

• Drain IPI pools after fuel removal (Dec 2008)

• Over time, groundwater concentrations are expected to decrease

• Groundwater attenuation trends will be assessed through long term monitoring

Long-term Ground Water Monitoring Purpose

" Monitor status of current plumes

• Collect data to calculate potential doses due to GW

• Provide timely identification of potential new leaks

• Monitor effectiveness of any remediation / intervention actions I..............

I................................................

25

Long-term Ground Water Monitoring Program Elements - Monitoring Wells

• Boundary and Riverfront welts

• Selected wells along affected areas of the site

• Frequencies established for long-term monitoring

- Quarterly, Semi-annual and Annual

• Investigative criteria and actions defined

• Institutionalized in plant procedures 26

Remediation Strategy Source Control/Elimination combined with monitored natural attenuation

• Unit 1 Continued source control via in-pool demineralization system Source elimination via complete fuel removal and pool draining (2008)

• Unit 2 Unit 2 transfer canal liner pinhole repair (leak cessation)

Continued utilization of existing wall collection box (control)

• Long-term program to monitor plume attenuation (reduction) and provide for early identification of new potential leaks.

II I...........

I..............................................

................. I.,... I.,

I I...............

,f ",

Conclusions No impact to public health or safety from ground water contamination at Indian Point No contamination observed in off-site wells or reservoirs Calculated doses are less than 1% of regulatory limits, and no actual contaminants attributable to the plant have been detected in the Hudson River water or fish.

• Source of leaks have been identified

• Remedial actions have been implemented with final actions to be completed by yearend 2008.

I..................

I..........

I.........................................................

I...................

1. I..........................

...............................