ML080290204

Memorandum on Synopsis of Long Term Monitoring Plan Bases for Indian Point Groundwater

ML080290204
Person / Time
Site:	Indian Point
Issue date:	01/25/2008
From:	Barvenik M GZA GeoEnvironmental
To:	Donahue P Entergy Nuclear Northeast, Office of Nuclear Reactor Regulation
Boska J, NRR, 301-415-2901
References
FOIA/PA-2010-0209
Download: ML080290204 (9)

Text

MEMORANDUM TO:

Mr. Patrick Donahue - Entergy Nuclear Northeast FROM:

Matthew Barvenik - GZA REVIEWED BY: Michael Powers - GZA DATE:

January 25, 2008 RE:

Memorandum - Synopsis of Long Term Monitoring Plan Bases New York Two Pennsylvania Plaza Suite 1860 New York, NY 10121 Phone: 212-594-8140 Fax: 212-279-8180 Connecticut 27 Naek Road Vernon, CT 06066 Phone: 860-875-7655 Fax: 860-872-2416 Massachusetts One Edgewater Drive Norwood, MA 02062 Phone: 781-278-3700 Fax: 781-278-5701 As requested, the following provides a synopsis of the bases1 which underpin the Long Term Monitoring Plan (LTMP) currently being implemented at the Indian Point Energy center (IPEC)

Site. These bases were derived from the Conceptual Site Model (CSM)2 which was developed and refined during over two years of comprehensive hydrogeologic investigations completed at the Site, and as described in the Final Report3. During the progress of the investigations4, Entergy also conducted regular and frequent meetings where GZA presented existing data and exchanged concepts with representatives of the United States Nuclear Regulatory Commission (NRC), the United States Geological Survey (USGS), and the New York State Department of Environmental Conservation (NYSDEC). This interchange of concepts, as well as information garnered during stakeholder and public meetings, was used to help set the course of the then ongoing investigations. Based on the outcome of these investigations and the resulting CSM, GZA has formulated and recommended to Entergy a LTMP design, which Entergy has adopted.

The overall LTMP design was formulated to satisfy four primary objectives:

1. Monitor groundwater to both detect and characterize current and potential future off-Site groundwater contaminant migration to the Hudson River from abnormal radionuclide releases of liquid effluents, so as to allow computation of potential radiation dose to the public;

2. Monitor groundwater along the southern property boundary to confirm that contaminated groundwater is not migrating off of the property in that direction; 1 It is noted that the sampling installations referenced herein are a compilation of the LTMP as well as the 80-10/Effluents Programs.

2 GZA used the Observational Method (see Section 2.0 of the Final Report) to guide our investigations, identify and fill data gaps, assess the reasonableness of findings, and develop parameters controlling contaminant transport, and ultimately to formulate the CSM. This is inherently an iterative process and, as studies progressed, the CSM was refined to better fit observed conditions.

With completion of the investigations, the CSM was consistent with both the Site-specific project data and published data for the area (see Section 3.0 of the Final Report).

3 Final Hydrogeologic Investigation Report, GZA GeoEnvironmental, Inc; January 7, 2008 4 The investigations included approximately 60 shallow and deep, overburden and bedrock, single and multi-level instrument installations, as well as footing drain and man hole sampling points, which encompass approximately 150 individual sampling intervals. A subset of this overall monitoring installation network, as summarized on Figure LTMP 1, is used to provide the data for the LTMP. The level of redundancy designed into the LTM network anticipates and allows for the loss of a number of monitoring zones without significant impact to the adequacy of the monitoring system.

Indian Point Energy Center January 25, 2008 File No. 17869.10 Page 2

3. Monitor groundwater proximate to Systems, Structures and Components (SSCs) which exhibit a credible probability of resulting in a visually undetected release of radionuclides to the subsurface carrying an activity level of significance; and

4. Monitor the groundwater plumes identified on-Site to demonstrate overall reductions in total activity over time as is consistent with the requirements of Monitored Natural Attenuation (MNA)5, the selected remediation for the IPEC Site.

These objectives are consistent with and fully encompass the guidance provided in the NEI Groundwater Protection Initiative.

To address objectives 1) and 2) above, groundwater monitoring installations have specifically been installed, and are currently being monitored, to both detect and characterize current and potential future off-Site groundwater contaminant migration to the river, both directly and through the Discharge Canal6. Additional installations have also been installed specifically for monitoring of the southern Site property boundary7.

The IPEC Site was subdivided into six individual groundwater flow zones, with each including a separate shallow and deep flow zone. The instrument installations specifically targeted to monitor these individual zones, and the associated discharge pathways to the Hudson River, are outlined in the attached Dose Computation Monitoring Installation Matrix. As shown on Figure LTMP-1 (included herewith), the multi-level sampling network is concentrated in the Unit 2 and Unit 1 areas given that this is where contaminant concentrations are by far the highest8.

To address objective 3) above, monitoring installations have also been installed downgradient9 of, and in close proximity to, both identified and potential critical Structures, Systems and Components (SSCs). The specific monitoring installations which target locations where identified and credible potential future sources of leakage might exist10 are outlined on the attached Potential Source Monitoring Installation Matrix. These installations, in concert with specific footing drain monitoring, provide earlier detection of potential future leaks associated with the power generating units than would be possible with boundary wells alone.

To address objective 4) above, monitoring installations have been strategically placed to monitor the behavior of the plumes identified on the Site (see Figure LTMP-1). Because of the nature and age of the releases, groundwater contaminant migration rates, and interdictions by Entergy to eliminate/control releases, the groundwater contaminant plumes have reached their maximum 5 The selection of MNA as the remediation for the Site is more fully discussed in Section 11.0 of the Final Report.

6 The methods used to monitor and compute the magnitude of radiological release to the river, and justification for their selection, are more fully discussed in Section 6.0 of the Final Report.

7 Selection of appropriate installations to monitor the southern property boundary in light of groundwater elevation transients are more fully discussed in Section 6.6 of the Final Report.

8 The monitoring installations located downgradient of Unit 3 are judged sufficient for monitoring and computations in this area given the low contaminant concentrations measured, even in the typically more contaminated shallow flow regime.

9 Groundwater flow contours are provided on Figure LTMP-1, attached herewith, to demonstrate the groundwater flow pathway relationships between the potential source and the monitoring installation locations.

10 The identification of contaminant sources and release mechanisms on the Site is more fully discussed in Section 8.0 of the Final Report.

Indian Point Energy Center January 25, 2008 File No. 17869.10 Page 3 spatial extent and should now decrease over time11. The specific instrument installations which target the monitoring of these plumes are summarized on the attached Plume Attenuation Monitoring Installation Matrix. This monitoring is intended to verify that reductions are occurring in an anticipated manner.

Groundwater testing is performed quarterly on the majority of the LTMP installations, with some sampled semi-annually and the rest remaining on standby to provide added detail, if required. The sampling frequencies, targeted analysis suites, radionuclide analyses MDCs, and investigation trigger levels and associated action procedures are provided in the Radiological Ground Water Monitoring Procedures12. During long term monitoring, GZA anticipates that contaminant concentrations in individual monitoring wells will fluctuate over time (increasing at times as well as decreasing, as potentially related to precipitation events), and that a future short term increase in concentrations does not, in and of itself, indicate a new leak. In addition, it is also expected that some areas within the plumes will exhibit faster decay rates than others. Both behaviors are commonly observed throughout the industry with groundwater contamination sampling and analyses, and therefore, conclusions pursuant to plume behavior and the potential for new leaks must be evaluated in the context of all of the Site-wide monitoring data. Overall, however, GZA believes that the continuing monitoring will demonstrate decreasing long term trends in groundwater contaminant concentrations over time given the source interdictions completed by Entergy.

We appreciate the opportunity to be of service to you. Should you have any questions or comments, please feel free to contact me (781) 278-3805.

Very truly yours, GZA GEOENVIRONMENTAL, INC.

Matthew J. Barvenik, LSP Michael Powers, PE Senior Principal Consultant/Reviewer Attachments: Figure LTMP -1 Potential Dose Computation Monitoring Installation Matrix Potential Source Monitoring Installation Matrix Plume Attenuation Monitoring Installation Matrix.

11 The temporal and spatial behavior of the plumes identified on the IPEC site are more fully discussed in Section 9.0 of the Final Report.

12 Radiological Ground Water Monitoring Program; IPEC Site Management Manual; IP-SMM CY-110; January 11, 2008.

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I-2 U3-3 U3-2 U3-1 RW-1 MW-67 MW-66 MW-37 MW-36 MW-35 MW-34 MW-33 U3-4S U3-4D MW-52 MW-51 MW-50 MW-49 MW-47 MW-46 MW-45 MW-44 MW-42 MW-41 MW-38 MW-32 MW-31 MW-40 MW-48 MW-43 MW-39 U3-T2 U3-T1 MW-65 MW-62 MW-60 MW-59 MW-57 MW-56 MW-55 MW-54 MW-53 MW-30 MW-64 MW-61 MW-63 U1-CSS MW-105 MW-101 MW-110 MW-111 MW-112 MW-108 MW-107 MW-58 MW-109 storage Gravel Gravel Storage No Access Grass Earth Parking Asphalt Asphalt curb Asphalt parking Asphalt Concrete curbs Sign Concrete curb Concrete Concrete sidewalk Concrete curb Wooden curb Concrete sidewalk Concrete sidewalk Grass Concrete sidewalk Concrete sidewalk A/C UNIT Handicap ramp Concrete sidewalk A/C unit on concrete Concrete sidewalk Conc. sidewalk Concrete sidewalk Stone curbs Asphalt drive Asphalt parking Asphalt parking Asphalt parking Asphalt parking Asphalt curb Asphalt sidewalk Shrubs Trans.

Asphalt Concrete sidewalk Concrete sidewalk Transformer area and switch gear Storage Containers A/C Units Grass Concrete curb Grass Shrubs Concrete sidewalk Conc. sidewalk Wooden walk Open grate Asphalt drive Asphalt Asphalt Asphalt Asphalt Asphalt Asphalt Asphalt Asphalt drive Asphalt Asphalt Drive Sidewalk Gravel Gravel Transformer yard Asphalt Drive this Area No Access Asphalt Concrete Retaining Wall Stone retaining wall Gravel parking Concrete sidewalk Gravel parking Gravel parking Asphalt parking Asphalt parking Concrete curb Concrete sidewalk curb pad Asphalt curb Asphalt curb Asphalt curb Grass Gravel parking Storage Grass Asphalt drive Storage units Gravel Parking lot Asphalt Concrete sidewalk Overhead walkway Concrete curb Asphalt parking Concrete walk Asphalt parking Asphalt Asphalt Asphalt Wood walk Asphalt Concrete walk Concrete pier Courtyard Asphalt Rip-rap Sidewalk Concrete 110 140 120 130 30 30 40 50 30 40 50 90 70 70 80 90 80 80 90 100 110 110 110 110 120 120 100 70 60 70 80 90 60 80 90 100 100 140 140 Transformer Gravel Covered Concrete Asphalt parking Transformers on raised Concrete Pad Trans.

Transformers Concrete slab Grass Transformers on raised Concrete Pad Concrete Bridge Concrete Bridge Transformer Substation "H" Trailer Trans Asphalt Trans Trans Trans Concrete sidewalk Asphalt Grass Vent pit Mach.

stand Transformers Yard (Gravel)

DISCHARGE OUTFALL CANAL Gravel Shrubs Shrubs Shrubs Overhead Crane Grass FUEL TRANSFER POOL STORAGE POOL STORAGE POOL FAILED FUEL AUX. POOL DISASSEMBLY POOL CASK LOAD POOL CASK WASH & DISASSEMBLY ISOLATION PIT ROOF DRAIN ELEVATION 65' 43.8' 43.8' 43.8' 21.75' 22.75' (EL.=0.0) 33' 13' 43.8' 33' 33' 33' 33' 33' 42.5' 42.5' MH-4 MH-4A MH-5 MH-6 MH-2 CB-B6A CB-B6 U3-CB-B5 U3-CB-B4 U3-CB-B4A U3-CB-B3 U3-CB-B3A U3-CB-B2A U3-CB-B2 U3-CB-B1 U3-CB-A2 U3-CB-A1 U3-MH-14 F5 U3-CB-A2A CB-B CB-E CB-F CB-1 (CB-G)

CB-3 D2 U3-CB-B7 B5 U3-CB-B8 XX CB-33 CB-34 CB-15 CB-14 CB-13 CB-32 CB-31 CB-30 U3-CB-A7 (U3-CB-11)

U1-CB-22 U3-CB (U1-CB-10)

CB-29 U3-CB (U1-CB-9)

U1-CB-21 U1-CB-20 CB-28 CB-24 (CB-24)

CB-27 E16 E16 E16A CB-6 CB-5A (CB-6)

CB-5B CB-7 CB-5 MH16 CB-3B CB3A CB4 CB-2C CB3 CB-2B CB-2A CB-2 CB-1 MH18 MH8 MH17 MH7 MH23A CB-16 MH9 MH10 MH11 MH22 MH21 MH13 MH3 MH12 MH1 CB-18 MH15 CB-19 CB-23 MH14 C2 E7 E6 E8 E9 E10 E11 E5 E5A E4 E4 E4A E3B E3 E3A F3 F4 CB E2 E2A F6 F7 E2B E2C U3-CB-E1 U3-CB-A6 U3-CB-A5 CB-A3A U3-CB-A3 U3-CB-A4 E14 E15 E15A (U1-CB-8)

AB E13 E12 D1 CB-17 40 30 20 10 5

20 13 50 40 30 20 10 5

50 Turbine Generator Building 2 Turbine Generator Building 1 Turbine Generator Building 3 Transformer Yard PAB FUEL POOL UNIT 2 1,015' 640' WEST FUEL POOL UNIT 1 UNIT 3 U2-C1 HR-1 U3-C1 OUT-1 2

2 2

33'UTILITY TUNNEL 33' UTILITY TUNNEL CSS CSS TRENCH NORTHERN CLEAN ZONE UNIT 1/2 UNIT 2 NORTH UNIT 3 NORTH UNIT 3 SOUTH SOUTHERN CLEAN ZONE H U D S O N R I V E R J:\\17,000-18,999\\17869\\17869-10.DW\\Figures\\GIS\\MXD Documents\\17869-10_LTMP-1_Long Term Monitoring Plan.mxd Plant North N

N 50 0

50 100 150 25 Feet Figure No.:

Job No.:

Dwg. Date:

Proj. Mgr.: MJB Designed By: MJB Reviewed By: MJB Operator: GAS 41.0017869.10 1-23-2008 LTMP-1 INDIAN POINT ENERGY CENTER BUCHANAN, NEW YORK GZA GeoEnvironmental, Inc.

One Edgewater Drive Norwood, MA 02062 Phone: (781) 278-3700 Fax: (781) 278-5701 LONG TERM MONITORING PLAN LONG TERM MONITORING PLAN

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? LAF-03 LAF-02 LAF-01 H U D S O N R I V E R 1,557.1' LAFARGE WELLS LEGEND General Notes:

1. Base map was developed from an untitled electronic file provided by Badey

& Watson Surveying and Engineering, P.C., Dated 2/3/06; CAD file name : "GZA.dwg".

2. Additional Long Term Monitoring Plan information is provided in the Hydrogeologic Site Investigation Report, GZA GeoEnvironmental, Inc. January 7, 2008 Containment Spray Sump Pipe Trench Probable Legacy Release Locations Terminated Connection To Storm Drain Footing Drain Exfiltration Inter-Structure Joint / Mud Mat Unit 1 West Fuel Pool Unit 2 Fuel Pool Data Notes:

1. H3 bounding isopleths / data represent upper bound values measured over both depth and time (available results for sample dates through 8/28/2007). As such, the "plume" is an overstatement of contaminant levels actually existing on-site at any time.

Data Notes:

1. Sr-90 "bounding isopleths" / data represent upper bound values measured over both depth and time (available results for sample dates through 8/28/2007). As such, the "plume" is an overstatement of contaminant levels actually existing on-site at any time.

2. Three discrete isopleths have been drawn around MW-39, 41, and 43 given measured concentrations greater than 2 pCi/L. It is expected that similar concentrations exist at other locations along the legacy piping alignment in addition to the locations shown.

Current and Potential Source Areas Unit 1 Sr Potential Source Unit 2 and Unit 3 H3 Potential Source Boring / Monitoring Installation Designation MW-30 Longterm Boring / Monitoring Installation

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Inactive Boring / Monitoring Installation

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Groundwater Elevation Contours Contours Other Than 10' Interval Ambient "Watertable" Contours 6/1/2007 (10' Interval) 20 5

Streamtubes Activity Data 1

1 0

200 100 Feet Isopleth Bounding Activity H3

> 5,000 pCi/L Bounding Activity SR90

> 2 pCi/L EASTERN IP1-CB FLOW PATH SOUTH WESTERN IP1-CB FLOW PATH PRIMAR Y

IP1 FL OW P ATH LEGACY IP1 STORM DRAIN FLOW PATH IP1-CSS TRENCH FLOW PATH

Dose Computation Monitoring Installation Matrix Groundwater Flow Zone1 Activity to Discharge Canal2 Activity to Hudson River2 Northern Clean Zone NA NA Unit 2 North MW-52 MW-60 MH-1 MH-12 Unit 1/2 MW-36 MW-37 MW-55 MW-49 MW-50 MW-66 MW-32 MW-67 MW-53 MH-4A MH-14 Unit 3 North MW-54 MW-62 MW-58 MW-63 CB-14 CB-15 CB-34 Unit 3 South U3-T2 CB-3 U3-T1 U3-4D MW-44 MW-41 U3-CB-B8 Southern Clean Zone MW-51 CB-E13 MW-40 CB-C2 CB-xx CB-D1 CB-E6 CB-E8 NOTE:

1 Additional Long Term Monitoring Plan information is provided in the Hydrogeologic Site Investigation Report; GZA GeoEnvironmental, Inc.;

January 7, 2008.

2 It is noted that the sampling installations referenced herein are a compilation of the LTMP as well as the 80-10/Effluents Programs.

Potential Source Monitoring Installation Matrix Potential Source1,2 Primary3,5 Secondary4,5 Monitoring Installation Monitoring Installation Unit 2 Spent Fuel Pool MW-30 MW-33 MW-31 MW-35 MW-32 MW-111 MH-5 MW-36 MW-37 MW-55 MW-52 Unit 2 Transfer Canal MW-30 MW-33 MW-31 MW-35 MW-32 MW-111 MH-5 MW-36 MW-37 MW-55 MW-52 Unit 2 Transfer Tube MW-30 MW-33 MW-31 MW-35 MW-32 MW-111 MH-5 MW-36 MW-37 MW-55 MW-52 Unit 2 Rad Waste Transfer Line to Unit 1 MW-33 MW-55 MW-35 MW-36 MW-111 MW-37 U1-CSS MW-50 Unit 2 Drain Line under MOB MW-31 MW-33 MW-30 MW-35 MW-32 MW-111 MH-5 MW-36 MW-37 MW-55 MW-52 Unit 2 Drain Line under Fan House MW-30 MW-35 MH-5 MW-111 MW-33 MW-36 MW-37 MW-55 MW-52 Unit 2 Primary Auxilary Building Sump MW-33 MW-36 MW-35 MW-37 MW-111 MW-55 MW-52 Unit 2 Refueling Water Storage Tank & piping MW-42 MW-32 NCD MW-55 MW-53 MW-54 MW-33 MW-36 MW-35 MW-37 MW-111 Unit 2 Primary Water Tank MW-42 MW-32 NCD MW-55 MW-53 MW-54 MW-33 MW-36 MW-35 MW-37 MW-111 Unit 2 Waste Holdup Tanks and floor drain MW-31 MW-30 MW-32 MH-5 MW-42 MW-33 NCD MW-35 MW-53 MW-111 MW-55 MW-54 Unit 2 VC footing drain MH-5 MW-52 MW-36 MW-37 Unit 2

Potential Source Monitoring Installation Matrix Unit 1 Spent Fuel Pools - Primary (NCD) Flow Path NCD MW-55 MW-42 MW-36 MW-53 MW-37 MW-54 SFD Sump Unit 1 Spent Fuel Pools - Eastern CB Flow Path CSB Drain MW-53 NCD MW-42 SFD Sump Unit 1 Spent Fuel Pools - Southwestern CB Flow Path MW-56 MW-57 MW-54 MW-50 CSB Drain SFD Sump Unit 1 Spent Fuel Pools - CSS Trench Flow Path U1-CSS MW-55 MW-57 MW-50 MW-54 Unit 1 CSS U1-CSS MW-55 MW-57 MW-50 MW-54 Unit 1 Legacy Storm Drain Piping MW-39 MW-44 MW-41 MW-45 MW-43 MW-46 MH-B6a MH-B1 U3-T1 U3-T2 Unit 3 Spent Fuel Pool & Transfer Canal MW-44 U3-T1 MW-45 U3-T2 MW-46 MH-B6a MH-B1 Unit 3 Transfer Tube Sleeve Drain MW-44 U3-T1 MH-B6a U3-T2 MH-B1 Unit 3 VC and FSB Anular Space MW-44 U3-T1 MH-B6a U3-T2 MH-B1 Unit 3 2" Liquid Waste & 3" Containment Blowdown Piping MW-44 U3-T1 MH-B6a U3-T2 MH-B1 Unit 3 Primary Auxilary Building Sump & Floor Drain Piping MW-46 MH-B1 MH-B6a U3-T1 U3-T2 Unit 3 Fan House Floor Drain Piping MH-B1 MW-46 MH-B6a U3-T1 U3-T2 Unit 3 Refueling Water Storage Tank & Piping MW-39 MH-B6a MW-41 MH-B1 MW-44 MW-46 MW-45 U3-T1 U3-T2 Unit 3 Primary Water Tank MW-41 MW-45 MW-43 MH-B6a MW-46 MH-B1 U3-T1 U3-T2 Unit 3 Waste Holdup Tank & Floor Drain Piping MW-41 MW-45 MW-43 MH-B6a MW-46 MH-B1 U3-T1 U3-T2 Unit 1 Unit 3

Potential Source Monitoring Installation Matrix NOTES:

5 It is noted that the sampling installations referenced herein are a compilation of the LTMP as well as the 80-10/Effluents Programs.

3 Primary Monitoring Installations are those generally closest to a potential source and most likely to initially detect a release. 4 Secondary Monitoring Installations are those that are located futher down or cross gradient from a potential source.

1 Potential Sources are Systems, Structures or Components which exhibit a credible probability of resulting in a visually undetected release of radionuclides to the subsurface with an activity of significance.

2 Additional Long Term Monitoring Plan information is provided in the Hydrogeologic Site Investigation Report; GZA GeoEnvironmental, Inc.; January 7, 2008.

Plume Attenuation Monitoring Installation Matrix Plume Source Source Area Down Gradient Monitoring Installation4 Monitoring Installation4 Unit 2 Spent Fuel Pool (direct GW flow )1,3 MW-30 MW-36 MW-33 MW-37 MW-111 MW-67 MW-66 Unit 2 Spent Fuel Pool (eastern unsaturated zone flow)2,3 MW-31 MW-30 MW-33 MW-111 MW-36 MW-37 MW-67 MW-66 Unit 2 Spent Fuel Pool (southern unsaturated zone flow)2,3 MW-32 MW-33 MW-42 MW-35 MW-53 MW-111 MW-36 MW-55 MW-37 MW-50 MW-49 MW-67 MW-66 MW-62 Unit 1 Spent Fuel Pools - Primary (NCD) Flow Path3 MW-42 MW-55 MW-53 MW-36 MW-37 MW-54 MW-50 MW-49 MW-67 MW-66 Unit 1 Spent Fuel Pools - Eastern CB Flow Path3 MW-42 MW-55 MW-36 MW-37 MW-54 MW-50 MW-49 MW-67 MW-66 Unit 1 Spent Fuel Pools - Southwestern CB Flow Path3 MW-56 U1-CSS MW-57 MW-54 MW-50 MW-49 MW-67 MW-66 MW-62 Unit 1 Spent Fuel Pools - CSS Trench Flow Path3 U1-CSS MW-55 MW-54 MW-37 MW-50 MW-49 MW-67 MW-66 Unit 1 Legacy Storm Drain Piping Flow Path3 MW-39 MW-44 MW-41 MW-45 MW-43 MW-46 U3-T1 U3-T2 NOTES:

4 It is noted that the sampling installations referenced herein are a compilation of the LTMP as well as the 80-10/Effluents Programs.

3 Additional Long Term Monitoring Plan information is provided in the Hydrogeologic Site Investigation Report; GZA GeoEnvironmental, Inc.; January 7, 2008.

2 Unsaturated zone flow designates those portions of the Tritium release that first migrate above the water table along fracture orientations in directions other than that of the groundwater flow prior to entering the groundwater, with migration along groundwater flow paths, thereafter.

Unit 1 Strontium Plume Unit 2 Tritium Plume 1 Direct Groundwater Flow designates that portion of the Unit 2 Tritium release that enters the groundwater below the IP2-SFP and then moves downgradient to the West.