ML15083A439

Erm Interim Investigation Report Prepared by Erm Services for Entergy LLC, Pilgrim Station, in March 2014

ML15083A439
Person / Time
Site:	Pilgrim
Issue date:	03/24/2015
From:	Daly M, Dow K, Jeffery Lynch ERM
To:	Entergy Nuclear Operations, NRC Region 1
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References
Download: ML15083A439 (56)

Text

The words leading sustainability consultancy 7800 Interim Tritium Investigation Report (Logic Report)

Pilgrim Nuclear Power Station Plymouth, Massachusetts Entergy Nuclear Operations, Inc.

March 2014 www.erm.com

Entergy Nuclear Operations, Inc.

Interim Tritium Investigation Report (Logic Report)

Pilgrim Nuclear Power Station Plymouth, Massachusetts March2014 ERM Reference 0114809 PNPS Ucensing Manager Senior Consultant-ERM Matthew Daly, P.G.

Principal - ERM Environmental Resources Management One Beacon Street, Sth Floor Boston, Massachusetts 02108 T: (617) 646-7800 F: (617) 267-6447

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 i

TABLE OF CONTENTS EXECUTIVE

SUMMARY

1

1.0 INTRODUCTION

3 1.1 SITE BACKGROUND & LAYOUT 5

1.1.1 PNPS Facilities 5

1.1.2 PNPS Local Geology 6

1.1.3 PNPS Water Resources 7

1.2 REGULATORY OVERSIGHT 7

2.0 SYSTEMS OVERVIEW 11 2.1 SYSTEMS, STRUCTURES, AND COMPONENTS 11 2.2 HISTORIC SPILLS 15 2.3 MONITORING WELL NETWORK 16 2.4 CONCEPTUAL SITE MODEL 18 2.4.1 CSM Plan View 19 2.4.2 CSM Cross Section View 20 3.0 DIRECT AND INDIRECT SSC INVESTIGATIONS 23 3.1 INDIVIDUAL SYSTEM EVALUATIONS 23 3.1.1 Condensate Storage Tanks (CSTs) 23 3.1.2 Radwaste Discharge Line 25 3.1.3 Neutralization Sump and Discharge Pipe 26 3.1.4 Main Stack Lines 28 3.1.6 Building Roof Drains 30 3.2 GENERAL SITE EVALUATIONS 30 3.2.1 Monitoring Wells 30 3.2.2 Rainwater 33 3.2.3 Storm Water, Duct Banks & Surface Water 33 4.0

SUMMARY

35

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5.0 CONCLUSION

S 36

6.0 REFERENCES

38 LIST OF TABLES TABLE 1 TRITIUM RESULTS - PNPS MONITORING WELLS TABLE 2

SUMMARY

OF MONITORING WELL LOCATION AND CONSTRUCTION TABLE 3 PNPS SSC INVESTIGATIONS AND RESULTS LIST OF FIGURES FIGURE 1 SITE LOCUS MAP FIGURE 2 SITE PLAN FIGURE 3 CONCEPTUAL SITE MODEL - GROUNDWATER ELEVATIONS AND CONTOURS FIGURE 4 CONCEPTUAL SITE MODEL - PLAN VIEW FIGURE 5 SITE LAYOUT

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EXECUTIVE

SUMMARY

On behalf of Entergy Nuclear Operations, Inc. (Entergy), Environmental Resources Management (ERM) has prepared this Interim Tritium Investigation Report (Logic Report) to document investigation activities in response to recent tritium detections in groundwater at the Pilgrim Nuclear Power Station (PNPS) located in Plymouth, Massachusetts (Figure 1). This Logic Report was collectively prepared by ERM and PNPS personnel to summarize PNPS responses to the Nuclear Energy Institute Ground Water Protection Initiative (GPI), referred to as NEI 07-

07. The report systematically presents the results of investigations completed from 2007 through 15 December 2013, as well as reported releases discovered during this period. The report establishes a framework for future activities under PNPSs GPI.

Monitoring wells installed under the NEI 07-07 program have detected tritium in groundwater, but at concentrations below applicable standards.

A release of tritium was discovered in March 2013 and immediately reported to authorities, including the Nuclear Regulatory Commission (NRC) and the Massachusetts Department of Public Health (MDPH). The release of tritium was associated with a discharge event from the Neutralization Sump and apparent separations within the discharge pipe.

The discharge pipe was taken out of service and future releases associated with the pipe have been eliminated.

Numerous additional site investigations and inspections into other potential sources of release from systems, structures and components (SSCs) have been completed at PNPS. While the results of these activities indicate the SSCs appear intact and are not an active source of leakage, additional activities will be performed in attempt to identify other potential sources, and if identified, these SSCs will be dispositioned and/or removed from service.

Key findings of this Logic Report include the following:

1. Groundwater detections are limited to the PNPS property and data indicates the detections do not migrate offsite.

2. No tritium concentrations have been detected in any of the surface/bay water samples collected within the Intake Canal.

3. Groundwater at PNPS is not used as a source of drinking water supply. As such, the reporting threshold for tritium at PNPS is the NRC-approved standard for non-drinking water sources (i.e., 30,000 pCi/L).

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4. Since inception of the groundwater monitoring program in 2007, PNPS has installed 22 groundwater monitoring wells. Concentrations of tritium have been detected in select monitoring wells, and the highest detected concentration, as of 15 December 2013, was 25,552 pCi/L detected in 2010 at well MW-205. Since the historical peak detections at MW-205 in 2010, concentrations have declined over time.

5. A release of tritium in March 2013 was discovered during a discharge event from the Neutralization Sump. The release was immediately reported to authorities, and the discharge pipe was immediately taken out of service to eliminate future releases associated with the pipe.

6. A comprehensive review of systems, structures and components (SSCs) that represent potential sources to groundwater has been undertaken and continues.

7. Given the ongoing nature of the investigation and response actions, this Logic Report is considered an interim report, and may be updated in the future as new information warrants updating this report.

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1.0 INTRODUCTION

On behalf of Entergy, ERM has prepared this Interim Tritium Investigation Report (Logic Report) to document the history, scope and results of investigations completed to date relating to potential inadvertent releases of radionuclides to soil and groundwater due to operations at PNPS. PNPS, as well as all commercial nuclear power plants in the United States, committed to establish site-specific groundwater protection programs in order to detect, minimize, and eliminate inadvertent radiological impacts to groundwater. The industry wide commitment, known as the Ground Water Protection Initiative (GPI), was galvanized by the Nuclear Energy Institute (NEI) in 2006 and is referred to as NEI 07-07 (NEI, 2007).

Since initiating a site-specific NEI 07-07 groundwater protection program in 2007, a total of 22 monitoring wells have been installed at PNPS.

Concentrations of tritium in groundwater have been detected above background levels in select monitoring wells at PNPS. The highest detections in PNPS wells are summarized in the following table:

Well ID Well Installation Date Highest Tritium Detection (pCi/L)

Date of Highest Detection Tritium Detection on 2 December 2013 (pCi/L)

MW-205 28 April 2010 25,552 7 July 2010 669 MW-206 28 April 2010 13,600 1 November 2010 908 MW-216 6 September 2012 8,700 18 November 2013 6,140 Notes:

1. pCi/L = picocuries per liter

2. Reporting threshold for PNPS is 30,000 pCi/L, which is the NRC-approved Offsite Dose Calculation Manual standard for tritium in non-drinking water sources (20,000 pCi/L U.S. Environmental Protection Agency drinking water standard is not applicable, as groundwater at PNPS is not used as a source of drinking water)

3. Highest 2013 detection includes analysis of results through 15 December 2013 The results indicate that one or more sources of tritium release have occurred during PNPSs operations. In response to the elevated detections, PNPS has performed numerous evaluations and inspections to assess the potential source(s) of radiological release. A release of tritium

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in March 2013 was discovered during a discharge event from the Neutralization Sump. The release of tritium was associated with the discharge pipe from the Neutralization Sump and separations within the discharge pipe. The discharge pipe was taken out of service and future releases associated with the pipe have been eliminated. The March 2013 release was communicated to the Nuclear Regulatory Commission (NRC) and Massachusetts Department of Public Health [(MDPH Bureau of Environmental Health (BEH)], the state agency responsible for regulating potential offsite public health impacts associated with the operation of commercial nuclear power plants in Massachusetts.

The scope of GPI investigations and associated results are communicated regularly with the MDPH, Massachusetts Emergency Management Agency (MEMA), and the NRC. Since 2010, MDPH and MEMA officials have been conducting weekly status calls with PNPS regarding the GPI program. In 2010, MDPH conducted an independent review of PNPSs site history, including geology, groundwater characteristics and GPI program activities to date. The results of this review were documented in a MDPH letter to PNPS (MDPH, 30 June 2010), which concluded that additional monitoring wells and sampling activities were warranted in order to demonstrate no offsite migration of tritium impacts detected at the time.

Since issuance of the 2010 MDPH letter, PNPS and MDPH officials have worked in a collaborative manner during the tritium in groundwater investigation. Face-to-face meetings are held to discuss the status of GPI activities and results (both technical and non-technical issues), with meeting attendance also including the MDPH/BEH, MEMA, the Massachusetts Department of Environmental Protection (MassDEP) and the NRC. The open dialogue between PNPS and Massachusetts agencies is considered by the NRC a model for the nuclear power industry.

The purpose of this Logic Report is to present the history of the GPI program at PNPS, including the site specific hydrogeology, Conceptual Site Model (CSM) for potential releases from SSCs to groundwater, investigation summaries, and reported releases. Given the ongoing nature of the investigation and response actions, this Logic Report is considered an interim report, and may be updated in the future as new information warrants updating this report.

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1.1 SITE BACKGROUND & LAYOUT 1.1.1 PNPS Facilities PNPS, located in Plymouth Massachusetts (Figure 1), is a 690 MW single-unit, boiling water reactor (BWR) originally constructed in the early 1970s.

Entergy acquired the assets and operations of the plant in 1999 from Boston Edison. The plant is located on 150-acres of a larger 1,700-acre property, with the majority of power plant operations east of Rocky Hill Road and along Cape Cod Bay. Key buildings and plant features are referred to as the Power Block and are constructed with deep foundations, resulting in many of the site operations to be located below ground surface (Figure 2). The Power Block buildings include the:

• Reactor Building - Structure containing the Boiling Water Reactor and associated support equipment and systems;

• Turbine Building - Structure containing the condensers, turbines, and generator designed for power generation of 690 MW;

• Radwaste Building - Structure supporting the handling, processing, and storage of radiological waste generated within the station; and

• Auxiliary Bay - Structure west of the Reactor Building containing internal systems and structures and components (SSCs) that support the Reactor Building.

In addition to the Power Block, additional site features at PNPS include the following:

• Intake Canal - A breakwater protected canal located immediately north of the Power Block on Cape Cod Bay to supply non-contact cooling to the station;

• Intake Structure - The structure constructed at the Intake Canal containing pumps and travelling screens for supplying non-contact cooling water from the Intake Canal to the Power Block;

• Discharge Channel - An open channel routing the discharge of non-contact cooling water back to Cape Cod Bay. All permitted liquid radiological releases associated with plant operation are through the Discharge Channel;

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• Main Stack Building - Structure housing the primary vent stack for the discharge of permitted radiological gaseous and water vapor releases generated at the Power Block;

• Switchyard - Directs generated power from the Turbine Building to the power distribution grid for offsite use; and

• Operations and Maintenance Building - Structure used for a variety of support services including warehouse, manufacturing and office needs.

The PNPS Power Block and majority of infrastructure are located on an engineered plain with a ground surface elevation of 22 feet above mean sea level (MSL). Ground floor elevation of plant structures is at 23 feet MSL. Plant features and engineering drawings use a site-specific coordinate grid system established during plant construction. All geographic positions and position referencing in this Logic Report are consistent with the plant grid system, which establishes plant north as shown on Figure 2.

1.1.2 PNPS Local Geology The PNPS Power Block and associated infrastructure are located within a surface water drainage basin that discharges to Cape Cod Bay. The up-gradient edge of this basin divide is located approximately 0.5 miles west-southwest of the Power Block and follows higher topographic elevations known as the Pine Hills, a regional glacial moraine deposit. The subsurface geology surrounding the PNPS Power Block consists of the following units:

• Construction Fill - engineered fill from a depth of 0 to 48 feet below ground surface (BGS) within the area originally excavated to support the Power Block buildings (Figure 2). The fill is placed around the deep building foundations and external SSCs, and consists of highly compacted fine to medium sand with some gravel.

• Glacial Outwash - alternating lenses and layers of sands, silts and clayey sands deposited in a natural depression east of the Pine Hills moraine. The Glacial Outwash has been subdivided into two units based on property analysis conducted during onsite geotechnical investigations:

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o Upper Sand (medium dense glacial outwash) - the upper section (0 - 48 feet BGS) of the Glacial Outwash deposit, this unit is less compact than the underlying Lower Sand.

o Lower Sand (dense glacial outwash) - the lower section (48 feet BGS down to surface of bedrock) and more compact than the overlying Upper Sand.

• Bedrock - bedrock beneath PNPS is composed of Dedham granodiorite, a hard and strong crystalline rock. The surface of bedrock is generally encountered at a depth of 90 feet BGS within the area of the Power Block.

The subsurface geologic units described above are depicted within the CSM presented later in this Logic Report and are shown on Figures 3 and

4.

1.1.3 PNPS Water Resources Site groundwater is not used as a source of drinking water at PNPS. The station receives drinking water from the Town of Plymouth, which supplies potable water from groundwater originating from 10 wells at various locations throughout the town (Town of Plymouth, 2011). The Wannos Pond Well represents the closest water supply well to PNPS and is located more than 2.5 miles south-southeast of the Power Block and within a separate watershed than PNPS.

For the evaluation of onsite groundwater for tritium under the NEI 07-07 program, a total of 22 monitoring wells have been installed at the site.

Tritium, a weak beta-emitting radionuclide with a 12.3 year half-life, has been identified in shallow groundwater at PNPS at levels exceeding two times the minimum detection limit, approximately 400 pCi/L, at wells MW-201, MW-205, MW-206, MW-209, MW-211, MW-215, and MW-216 (Figure 2). No radionuclides other than tritium have been detected in PNPS groundwater samples.

1.2 REGULATORY OVERSIGHT PNPS maintains a license to operate as a nuclear power plant in accordance with NRC regulations. Pilgrims original license was issued on 8 June 1972 and was renewed on 29 May 2012, authorizing the station to operate through 8 June 2032.

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In 2006, NEI initiated the Ground Water Protection Initiative, NEI 07-07, in order to develop a program for assessing, responding and communicating potential inadvertent leaks of radionuclides to soil and groundwater across the domestic fleet of nuclear power plants. As noted earlier, NEI 07-07 was endorsed by all utilities operating nuclear power plants, committing each plant to establish site-specific programs. While NEI 07-07 is a voluntary initiative, each plants program is inspected by the NRC personnel during annual NRC effluent inspections utilizing NRC guidance within Temporary Instruction 2515/185 (NRC, 2011), as well as by industry peer groups such as NEI and the Institute of Nuclear Power Operators (INPO).

Since NEI 07-07 was first initiated, the nuclear power industry has broadened efforts to eliminate inadvertent release of radionuclides to soil and groundwater. In December 2010, NEI released the Underground Piping and Tank Integrity (NEI 09-14) guideline (NEI, 2010). As a complement to the goals of NEI 07-07, NEI 09-14 is focused on; 1) inspecting underground safety related piping, 2) inspecting a sample of underground piping that convey or store licensed radiological materials, and 3) developing asset management plans to ensure systems long-term use with intended design.

The license renewal process at PNPS included NRC environmental and effluent inspections and evaluations of PNPSs safety features in order to document their ability to maintain a safe level of plant operation through the extended period of the operating license. The license renewal process also reviewed PNPSs potential environmental impact associated with extended operation. Collectively between license renewal, NEI 07-07, and NEI 09-14, PNPS has diligently investigated the potential environmental impacts associated with inadvertent release of radionuclides to soil and groundwater.

The NRC maintains a database of commercial nuclear power plants (NRC, 2012) in the United States that have discovered elevated levels of radionuclides in groundwater. Overwhelmingly, the dominant radionuclide detected at nuclear power plants in groundwater is tritium.

Human exposure to tritium in groundwater resulting in a dose can only be achieved through either ingestion or dermal contact of tritium impacted groundwater. The United States Environmental Protection Agency (US EPA) has established a drinking water standard for tritium at 20,000 picocuries per liter (pCi/L). For sites that do not use groundwater as a source of drinking water (i.e., as in the case of PNPS) NEI 07-07 established an industry reporting standard of 30,000 pCi/L.

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Due to the ability of tritium to move freely with groundwater, tritium is typically the first radionuclide detected if released to the soil or groundwater. As of December 2012, the NRC had documented that 44 of 65 nuclear power plant locations (including PNPS) have detected tritium in groundwater above the US EPA drinking water standard of 20,000 pCi/L (NRC, 2012). In all of these 44 cases, the NRC indicates that no detections have resulted in human exposure.

Since 2008, PNPS has been working collaboratively with MDPH, the state agency responsible for regulating potential offsite public health impacts associated with the operation of commercial nuclear power plants in Massachusetts. MDPH completed an independent review of PNPSs GPI program in 2010, consisting of a review of the site hydrogeology, monitoring well network, sampling program, potential sources of release and potential offsite impacts of concentrations detected in groundwater as of 2010. The MDPH report identified several gaps in the GPI program.

The gaps and associated recommendations by MDPH in 2010 included:

1. Installing at least two new monitoring wells east/southeast of facility buildings to better characterize groundwater flow and quality in this portion of the site;

2. Collecting surface/bay water samples from seawater inside the Intake Canal, specifically at locations immediately downgradient of observed tritium concentration to ensure no offsite detections associated with the groundwater pathway;

3. Performing additional characterization activities to strengthen site-specific groundwater flow directions and gradients in and around the PNPS Power Block and associated systems, structures and components that represent potential sources of release; and

4. Providing stronger assessment of potential sources of tritium to groundwater.

Each of the above recommendations was incorporated by PNPS into the GPI program.

Based on an agreement between PNPS and MDPH, the priority wells (MW-201, MW-205, MW-206, MW-209, MW-211, MW-215, and MW-216) are monitored on a bi-weekly basis, and certain wells, such as MW-209, MW-211, MW-216, MW-218 and MW-219 are currently sampled every week. The remaining wells are monitored on a quarterly basis. All groundwater samples are analyzed at an offsite commercial laboratory, with split samples analyzed by the MDPH.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 10 The working relationship between PNPS and MDPH has continued through time, with both parties working towards the common goal of identifying and eliminating the current source(s) to groundwater, and preventing offsite migration of any detected concentrations in groundwater at PNPS.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 11 2.0 SYSTEMS OVERVIEW 2.1 SYSTEMS, STRUCTURES, AND COMPONENTS As part of their NEI 07-07 program, PNPS staff from the Engineering, Operations, Chemistry and Radiation Protection Departments performed an evaluation of potential sources of tritium at PNPS. This evaluation developed a comprehensive listing of sources that have the potential to discharge tritium to either soil or groundwater. This evaluation looked not only at the individual SSCs, but also at operational procedures, past inspections, and the overall risks to the environment of each SSC. Over time, this list was expanded based on relevant plant operating experience (OE) from across the industry. SSCs that have the highest potential risk of an inadvertent release to the environment at PNPS are presented below, and are shown on Figure 5:

• Condensate Storage Tanks (CSTs) - The CSTs are two 275,000 gallon carbon steel tanks located directly north of the Reactor Building. The tanks sit over an engineered bed of sand, and the tanks are connected to the Reactor Building components through a series of subsurface piping that is accessible within a valve pit between the two tanks. The tanks are continuously operated with condensate water that has a typical tritium concentration of approximately 8,000,000 pCi/L.

• Radwaste Discharge Line - Provides the primary pathway for the permitted release of licensed liquid radiological effluents from PNPS.

The Radwaste Discharge Line (4-HE-20), is a subsurface four-inch diameter carbon steel pipe. Two 500-gallon tanks collect water from the shower drains, the chemistry lab and other locations within the Radwaste Building. After testing, water from these tanks is pumped through the Radwaste Discharge Line into the Discharge Channel. The line exits the south side of the Turbine Building, runs west along the south side of the Turbine Building and then along the west side of the Power Block, terminating at the Discharge Channel. A minor re-routing of the subsurface Radwaste Discharge Line was completed south of the Turbine Building in order to accommodate construction of the Off-Gas Retention Building. Radiological effluent discharge through the Radwaste Discharge Line occurs approximately once a year and is dependent on plant operations and schedule for refueling outages.

• Neutralization Sump and Discharge Pipe - The Acid Neutralization Sump is a 16,700 gallon concrete sump located below the floor level in

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 12 the Auxiliary Bay of the Power Block. This sump receives, holds and treats water from the Auxiliary Bay Salt Water Sump and from floor drains in the Auxiliary Bay. Water collected and treated in the Neutralization Sump is discharged through a four-inch diameter subsurface pipe that exits the western side of the Auxiliary Bay to the storm drain system at catch basin # 10 (CB10) and ultimately through the National Discharge and Elimination System (NPDES) permit Outfall 005 at the Discharge Channel. Since 2007, discharges of radiological effluent through the Neutralization Sump have ranged from one to 20 discharge events per year. The discharge pipe from the Neutralization Sump was the subject of a reportable release in 2013, which is described later in the report. The discharge pipe was taken out of service following discovery of the release.

• Main Stack Lines - the Main Stack Lines represent a subsurface piping bundle that runs between the Power Block and the Main Stack Building on the west side of the Power Block. Five subsurface lines within the Main Stack Line bundle convey either tritiated water vapor or tritiated water. The five potentially tritiated systems within the Main Stack Lines include:

o Off-Gas Duct Line (40-GD-8) - a 40-inch diameter pipe conveying tritiated water vapor from the Turbine Building to the Main Stack; o Gland Seal Hold-Up Line (16-HE-15) - a 16-inch diameter pipe conveying tritiated water vapor from the Turbine Building to the Main Stack; o Vent Duct Line (20-HE-44) - a 20-inch diameter pipe conveying tritiated water vapor from the Turbine Building to the Main Stack; o Loop Seal Line (2-HE-34) - a 2-inch pipe that conveys domestic water from the Turbine Building to the Main Stack; and o Stack Drain Line (2-HE-20) - a 2-inch diameter carbon steel line that conveys tritiated water from a sump beneath the Main Stack to a sump within the Reactor Building. The line is approximately 770 feet in length, beginning at elevation 50 feet MSL at the Main Stack and terminating at the Reactor Building floor drain sump at an elevation of -17 feet MSL. A repair was completed on the original Stack Drain Line during an historical excavation of the Salt Service Water lines west of the Reactor

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 13 Building following inadvertent damage to the Stack Drain Line during excavation activities. The repair area is approximately 2 feet east and 17 feet south of PNPS monitoring well MW-211.

The lines running to and from the Main Stack are used continuously during plant operation and may be isolated during planned refueling outages.

• Reactor Building Vent - A vent located on the southwest corner of the Reactor Building continuously releases gaseous effluents to the atmosphere at an elevation of approximately 181 feet above MSL.

Total tritium releases through the vent per year are within approved license limits. Once discharged to the atmosphere, gaseous tritium can potentially be washed out during precipitation events, resulting in localized rainwater around the station having elevated tritium concentrations. Atmospheric washout of tritium is not constant, and highly dependent on meteorological conditions leading up to, and during, the precipitation event. Rainwater with elevated tritium levels can become part of the overland flow or be a source of recharge to local groundwater. For overland flow that enters the storm water catch basin system, tritiated water would largely flow out through the NPDES outfalls, or potentially leak to groundwater from the catch basin system. In addition, tritiated rainwater can potentially enter the electrical duct manholes due to their subsurface configuration.

Specific atmospheric deposition pathways at PNPS include the following:

o Reactor Building Roof Drain - The roof drain for the Reactor Building connects to a drain line inside the building, which ultimately exits the Reactor Building in a subsurface pipe and connects into junction box (JB1), which then flows through the remaining storm water drainage system prior to being discharged under the site NPDES permit.

o Radwaste Truck Loc Roof Drain - The roof drain on the Radwaste Building connects to a drain line inside the building, which ultimately exits the Radwaste Building in a subsurface pipe and connects to junction box (JB3), which then flows through the remaining storm water drainage system prior to being discharged under the site NPDES permit.

o Electrical Duct Bank (Appendix R) System - The duct bank system consists of a series of manholes connecting electrical conduits within subsurface concrete duct lines. The system is

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 14 present largely within the north side of the Power Block, with connections to the Power Block on the east, north and west side of the Power Block. Water within the manholes has been observed at PNPS and could potentially leak into soil or groundwater. The source of water is most likely surface water runoff following precipitation events. Industry OE has documented that the air space within the duct lines are postulated as a potential pathway for tritiated water vapor to migrate from the Power Block. Assuming the water vapor could enter the individual conduits; the vapor could potentially condense into a liquid and subsequently enter soil or groundwater.

• Station Heating System & Guard Pipe - PNPS uses heated water to heat buildings and exterior above ground storage tanks during winter months. The heated water is conveyed within two 6-inch diameter pipes surrounded by concrete that are within a larger corrugated or guard pipe. While PNPS sampling of the heated water indicates this system is not a source of tritium, a small airspace associated with the physical orientation of the corrugations within the guard pipe are postulated as a potential pathway for tritiated water vapor to migrate from the Reactor Building. Assuming that water vapor could enter the guard pipe, the vapor could potential condense into a liquid and subsequently enter soil or groundwater.

The maintenance of subsurface piping at PNPS is based on a protective wrapping and coating applied to the piping during pipe installation and through a cathodic protection system. Currently, as well as during initial plant construction, all subsurface piping is field coated and wrapped in accordance with PNPS specifications. This specification covers the materials for and the procedure to be followed in the shop and field application of protective coating to underground steel pipe lines.

Methods of application, materials, and inspections are in accordance with the American National Standards Institute (ANSI)/American Water Works Association (AWWA) specifications for hot and cold applied coatings and tape. All coated piping utilized a coal tar tape wrap coating system. Wrappings were confirmed on selected subsurface pipe components during visual subsurface piping inspections completed in 2012.

The cathodic protection system is designed to limit the natural degradation of piping material due to the natural geochemistry of subsurface soils. Cathodic protection imposes a current between ground surface and the subsurface pipe to prevent oxidation along the exterior

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 15 surface of metal pipes and has been utilized at the site since construction.

An area potential-earth current (APEC) survey was also completed in December 2012 to assess the performance of the cathodic protection system.

The PNPS Underground Components Inspection Plan provides for the inspection of various subsurface piping systems in conformance with the December 2010 NEI Underground Piping and Tank Integrity (NEI 09-14) guideline. This guideline was developed to provide reasonable assurance of structural and leakage integrity of in-scope underground piping and tanks with special emphasis on piping and tanks that contain licensed materials.

The PNPS Spent Fuel Pool is not considered a potential source to groundwater at PNPS due to its physical location within the Reactor Building. The base of the Spent Fuel Pool is located 56 feet higher than the ground surface elevation around the Power Block, and no exterior walls of the Spent Fuel Pool are co-located with exterior walls of the Reactor Building. Any potential leakage of fuel pool water would be internal to the Reactor Building, which would be collected by floor drains that ultimately drain to the Reactor Building Sump. The PNPS Spent Fuel Pool has a visual leak detection system, which is checked daily by plant operations and inspected during plant refueling outages.

2.2 HISTORIC SPILLS A review of PNPS historic records contained in PNPS 10 CFR 50.75(g) files identified isolated instances where the inadvertent release (spills) of radiological materials (liquids or resins) occurred during plant operation.

Information on inadvertent releases aids in guiding potential site investigations to determine the potential for tritium releases to soils and ultimately the onsite groundwater. The following spill events have been documented:

• 1976 - Resin spill within the Protected Area - A small amount of resin spilled onto a plastic sheet but allowed a small amount of liquid to run onto the adjoining pavement. The resin and area were subsequently cleaned up, surveyed and documented.

• 1977 - Liquid spill at Radwaste Truck Loc - Demineralized water spilled onto the pavement outside of the Radwaste Truck Lock Door.

The water was absorbed with speedy dry, placed into 55-gallon drums for disposal and the area was surveyed, and documented.

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• 1981 - Resin spill west side Reactor Building - A small amount of resin leaked out of the building towards a storm drain. The resin was contained and cleaned up, the affected area was decontaminated, and the storm drains were surveyed for radioactivity. No detectable radioactivity was found.

• 1982 - Resin spill - Reactor Building Exhaust - A small amount of resin was exhausted while backwashing the condensate demineralizer resin.

The resin was removed and area was surveyed and decontaminated.

• 1988 - Liquid spill at Radwaste Building Truck Loc - Demineralized water spilling out onto the pavement in the yard when a water valve was left open. The affected areas were remediated, decontaminated, and surveyed and repaved. This spill was also reviewed by MDPH and documented in site records.

• 2013 - Liquid release from Neutralizing Sump Discharge Pipe -

Tritiated water was released during a discharge event from the Neutralization Sump in March 2013. The release occurred when tritiated water entered soil from a separation identified in the discharge pipe. The discharge pipe was taken out of service, and excavations were completed in July 2013 to investigate the nature of the release.

Other than the 2013 release identified above, the historic spills have not been connected to the elevated concentrations observed in the site groundwater monitoring wells.

2.3 MONITORING WELL NETWORK While initial groundwater wells were installed to monitor groundwater quality consistent with NEI 07-07 objectives, other groundwater monitoring wells have been added over time as part of the ongoing tritium in groundwater investigation. Wells are strategically positioned around the Power Block, as well as at background locations in order to assess site groundwater flow characteristics and water quality. The siting of each onsite well generally involved multiple attempts. Due to the orientation of multiple subsurface lines on site, a vactor truck was utilized to clear each location to ensure safe drilling. Table 1 presents a summary of monitoring well locations and construction data, with locations shown on Figure 2. As of 15 December 2013, a total of 1,316 groundwater samples have been collected and analyzed by PNPS as part of the PNPS NEI 07-07 groundwater protection program. In addition to the

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 17 groundwater samples, approximately 80 samples of surface/bay water have been collected for analysis. Table 2 presents tritium sampling results obtained at site wells.

As shown in Table 1, monitoring wells were installed at PNPS in varying phases from 2007 to 2013. The results of each phase of groundwater investigation were analyzed and used to guide the scope of successive investigations and well installation. The history and rationale of monitoring well installation campaigns is summarized as follows:

Date Wells Installed Well Purpose/Rationale 2007 MW-201, MW-202, MW-203 and MW-204 Initial GPI wells April 2010 MW-202I, MW-205, MW-206, MW-207, MW-208S/I Sentinel wells for near field monitoring of SSCs; MW-208S/I for establishing background August 2010 MW-209, MW-210, MW-211, MW-212, MW-213, MW-214 Investigation wells for elevated levels at MW-205, adding MW-213 and MW-214 per MDPH December 2011 MW-215, MW-217 Investigation wells for elevated levels at MW-205 September 2012 MW-216 Investigation well for elevated levels at MW-206 November December 2013 MW-218, MW-219, MW-4R MW-218 and MW-219 investigation wells for Neutralization Sump discharge line release, MW-4R to replace well MW-4 as a sentinel well Monitoring wells were positioned at specific locations in order to maximize their ability to monitor groundwater quality down-gradient of potential sources of release, and the wells are constructed in order to maximize their ability to serve as early detection in the event of new release(s).

As indicated in Section 2.4.2 below, the effects of hydrostatic pressure on the deep foundations prevents any potential active releases/spills from

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 18 deep portions of the buildings from entering deeper soil/groundwater.

Since there is no complete pathway for release to deep soil and/or groundwater from active releases/spills, monitoring wells at PNPS are focused on the shallower water table.

The depth of the water table at PNPS varies depending on the specific location onsite, as wells as through time due to local tides and precipitation events that recharge the aquifer. Around the Power Block, the water table ranges in depth from approximately 15 - 20 feet below ground surface. For tritiated SSCs that are physically located on ground surface or within subsurface piping, the well network and designed construction of well screens across the water table represent a comprehensive network for early detection of potential future releases.

Groundwater elevations obtained in September 2012 are presented on Figure 3.

2.4 CONCEPTUAL SITE MODEL The Conceptual Site Model (CSM) is a tool used to describe a sites conditions in the context of soil and groundwater resources; describing the physical, chemical, and biological processes controlling the availability and quality of groundwater, as well as potential sources that could impact groundwater quality. The CSM is a written description of the migration pathways, and is supported by schematics, to aid in designing an effective monitoring well network that will ultimately be used to identify and monitor the potential for inadvertent leakage. Typically, results of field investigations during well installation and subsequent monitoring are used to adjust or calibrate the CSM for site-specific conditions until the CSM is in reasonable agreement with field data. The CSM thereby becomes more robust and defensible over time as results are obtained, allowing the CSM to act as a valuable tool in stakeholder communication of overall site conditions.

As part of this Logic Report, ERM has documented the CSM for PNPS based on the hydrogeologic information collected at the site, which spans a 40+ year record to back when comprehensive geologic and hydrogeologic investigations were performed as part of original plant siting. The CSM incorporates PNPS specific construction details and layout, and incorporates data collected under PNPSs NEI 07-07 groundwater protection program.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 19 2.4.1 CSM Plan View The CSM begins with a plan view of PNPS and a description of groundwater flow paths, location of SSCs representing potential sources of radiological release and the effects of deep foundations on groundwater flow directions (Figure 3). Groundwater recharge to the regional glacial deposits occurs in the higher elevations west of the PNPS Power Block (Pine Hills), as well as through unpaved areas and into the engineered fill around the Power Block. For storm water runoff that enters the catch basin network, the potential for leakage from the storm water drainage system can also result in direct recharge to the engineered fill deposits around PNPS.

Shallow groundwater within the engineered fill around the Power Block is first encountered at the water table, where the subsurface soil transitions from unsaturated to saturated conditions. The slope of the water table follows the topography of the land surface, with higher groundwater elevations west and south of the Power Block, and lower groundwater elevations along the station boundary with Cape Cod Bay. In general, groundwater is found at a depth ranging from 15 to 20 feet below the ground surface around the Power Block.

A significant component of the plan view CSM is the site-specific direction of groundwater flow around the deep foundations of the buildings within the Power Block. Groundwater flow paths are perpendicular to the water table elevation contours, thus while bulk flow across the facility is from south to north, localized groundwater flow is diverted around the deep foundations within the Power Block. The deep foundations associated with these basements extend to a depth of approximately 40-45 feet below ground surface, and the depth to groundwater immediately outside these foundations ranges from 15-20 feet below ground surface. As a result of these foundation features, Figure 3 shows that groundwater flow paths and migration pathways are directed around and alongside the orientation of the Power Block. It is important to note that deep foundations also exist at the Intake Structure. As such, groundwater present west of the Power Block must flow between the deep foundations at the Intake Structure and Power Block.

For all SSCs located at or above the elevation of the water table, inadvertent spills and/or leakage would migrate down to the water table and then migrate from south to north across the site, with impacts restricted to either the west or east side of the Power Block foundations.

Leakage originating on the south side of the Power Block would need to migrate around the Turbine Building. For SSCs on the north side of the

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 20 Power Block, potential releases from these SSCs would migrate northeast towards Cape Cod Bay (Figure 3).

The following table presents a summary of SSCs identified at PNPS that normally contain tritiated water that could pose a potential release to soil and groundwater. The table also references site-specific monitoring wells that are located hydraulically down-gradient of each SSC which are currently used as a means of leak detection. The locations of SSCs are depicted on Figure 4.

PNPS External SSCs Containing Tritium System, Structure or Component (SSC)

Location Relative to Power Block Deep Foundations PNPS monitoring wells down-gradient of SSC Condensate Storage Tanks (CSTs) and associated piping North of Reactor Building MW-210, MW-202S/I, MW-201 Radwaste Discharge Line South and West of Turbine Building and Reactor Building MW-4R, MW-205, MW-207, MW-217, MW-211, MW-212, MW-209, MW-215, MW-204, MW-206, MW-216 Neutralization Sump &

Discharge Pipe West of Reactor Building MW-218, MW-219, MW-211, MW-215, MW-209, MW-205 Main Stack Lines South and West of Turbine Building and Reactor Building MW-207, MW-217, MW-212, MW-211, MW-215, MW-209, MW-204, MW-205 Reactor Building Vent to roof scuppers N/A - Atmospheric release / deposition All Site Wells Historic Spills Misc. Spill Locations based on available documentation MW-201, MW-206, MW-211, MW-216 Station Building Heating System North of Reactor Building MW,202, MW-202I, MW-205, MW-210 2.4.2 CSM Cross Section View The CSM includes a representation of source areas of potential radiological release in the context of the vertical hydrogeologic

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 21 environment. The path of the cross-section (shown in Figure 4) begins southeast of the Power Block and is orientated northeast through the Power Block and into Cape Cod Bay. This cross-section was developed using a 2.5:1 vertical exaggeration. Figure 4 also shows the native geologic units, base elevation of the excavation area, compacted fill areas, station buildings, existing monitoring wells, and PNPS infrastructure.

Analysis of PNPSs excavation depths and building components yields important considerations regarding the potential for leakage of radionuclides to groundwater. These observations are summarized as follows:

• The juxtaposition of the deep foundation walls and local groundwater conditions indicates that between 20 to 30 feet of hydrostatic pressure is present at the base of the PNPS Power Block. This hydrostatic pressure decreases moving up vertically in elevation along the outside of the foundation walls, until its lowest value is realized at the water table. The hydrostatic pressure phenomenon at PNPS precludes the ability for leaks from interior sumps and/or tanks from within the Power Block to migrate out and impact groundwater. Rather, the hydrostatic pressure results in the tendency for groundwater to migrate into the deep foundations at PNPS. This notion is confirmed by the occurrence of groundwater seepage into select areas of the deep foundation reported by PNPS. The Torus Room, located in the lowest elevations of the Reactor Building, has experienced seepage of groundwater that is both monitored and tested. Routine inspections and housekeeping ensures the area is maintained so no equipment is affected by groundwater. While groundwater intrusion has its own consequences, the hydrostatic pressure on PNPS deep foundations essentially eliminates the potential for leaks from sumps located at the base or sides of the deep foundation to leak out to groundwater. For example, tritiated systems including the Reactor Building Sump and Radwaste Storage Tanks are both present in deep areas of the Power Block but there are no release pathways to groundwater given the hydrostatic pressure. Since active releases/spills from deep foundations sumps into soil/groundwater are an incomplete pathway, monitoring wells at PNPS are focused on the shallower water table.

• Any inadvertent leakage of tritium from an above ground storage tank or buried piping system would result in the migration of tritiated water vertically down through the soil to the water table and subsequent detection in shallow groundwater. Monitoring wells have been installed as either sentinel wells, those wells that are immediately down-gradient of SSCs containing tritium, or as observation wells to

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 22 define changes in groundwater tritium concentrations and to pinpoint sources of elevated tritium.

• On the north side of the Power Block, the elevation of groundwater slopes down to Cape Cod Bay. As such, sub-marine groundwater discharge from PNPS to Cape Cod Bay occurs along the shoreline.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 23 3.0 DIRECT AND INDIRECT SSC INVESTIGATIONS A logical evaluation of site activities has been used to document the SSCs at PNPS, to describe the investigations performed specific to each SSC, to describe the anticipated groundwater impact in the event the SSC leaked, and to summarize PNPS groundwater data collected down-gradient of each SSC as means of leak detection. The logic train assists in determining whether or not the SSC is an active source to groundwater, and the framework for future monitoring.

The investigations presented below were completed by several entities, including PNPS plant personnel and subcontractors working on behalf of PNPS. Since this document provides for a logic rationale on determining the integrity of the SSC, investigations presented include both direct and indirect methods, which are defined as follows:

• Direct investigation - any investigation that includes a visual or physical test or inspection of SSCs to determine the integrity of the specific component; or

• Indirect assessment - any survey or assessment performed to infer the integrity of a SSC.

Using both direct and indirect methods, it is possible to present lines of evidence regarding the integrity of SSCs at PNPS in order to rule out potential sources to groundwater. Investigations at PNPS associated with NEI 07-07, NEI 09-14, and License Renewal Implementation are incorporated below for each SSC.

3.1 INDIVIDUAL SYSTEM EVALUATIONS 3.1.1 Condensate Storage Tanks (CSTs)

Direct investigations associated with the CSTs include the following:

• Exterior visual inspections of the CSTs and subsurface piping within valve pits are performed quarterly by PNPS plant operators. Records of these inspections are maintained at the station. Any items identified as a result of these inspections are addressed by PNPS staff and resolved.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 24

• Exterior physical testing of the subsurface piping components of the CSTs was performed using guided wave ultrasonic testing (GWT) in 2010. The focus of the inspections was to evaluate buried sections of piping through the placement of a transducer collar on non-buried sections of pipe inside buildings. Guided Wave technology uses ultrasonic waves to screen long lengths of pipe for the primary purpose of detecting irregularities in wall thickness that may be associated with corrosion and/or the erosion processes. A transducer collar sends out a burst of ultrasonic guided waves and then detects reflections indicative of changes in wall thickness. Conventional ultrasonic testing such as thickness gauging uses bulk waves and can be used to test the region of structure immediately below the transducer. A total of 12 GWT tests were conducted covering approximately 270 feet on 12 separate condensate water pipes. During this examination, GWT inspections detected one potential moderate indication. However, this location was found to be after the end of the specified end of the test range. Therefore, while there was a signal that indicates possible anomalies, it is possibly related to a large object resting against the pipe buried in the construction fill. All other piping systems tested had no indication of anomalies.

• Physical testing of the CST valve pit was completed in order to assess a potential pathway for leaks from the valve pit drain down to groundwater and to trace groundwater flow directions in this portion of the site. The testing activities performed by Ozark Underground Laboratories (Ozark), included adding four pounds of Rhodamine WT (20% dye equivalent, 80% diluent), an environmentally safe dye to humans and aquatic life in the concentrations used for groundwater tracing work, to the CST valve pit drain in February 2011. Water was added initially to wet surfaces in the drain prior to the addition of the dye. The liquid dye was poured directly into the drain followed by additional water to flush the dye from the drain and into the subsurface soils. While this drain also receives periodic influence of storm water runoff, additional flush water was added for several months following the dye introduction (5 gallons per week for 18 weeks) to facilitate the movement of the dye into local groundwater.

As of the last date of samples collected during the dye study (19 March 2012), Rhodamine WT dye was not detected at down-gradient wells.

The results to date either indicate 1) that groundwater flow around CST valve pit drain does not migrate toward any of the monitoring wells sampled; 2) that groundwater flow on the north side of the Reactor Building is minimal due to the presence of the deep foundations; or 3) that the volume of dye and water flushing may not

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 25 have been enough to effectively saturated the soil to allow leaching of dye down to the water table.

• Interior visual inspections of the CSTs were completed in May 2012 to ensure that notable degradation on the bottom of the CSTs was not occurring. The interior visual inspection was performed by underwater divers. Direct visual inspection of both CST tanks including the interior floor, walls and visually accessible portions of the roof area to assess the internal coating conditions and evaluate whether there was corrosion on the internal surfaces. The interior was cleaned and spot repairs were made to the internal coating of the tank as necessary.

• Interior physical testing of the CSTs was performed in May 2012 by performing ultrasonic thickness examination (UT) of the interior carbon steel making up the bottom plates within each CST. The purpose of the testing was to ensure that degradation on the bottom of the CST was not occurring. UT measurements taken during the test indicated that the floor plate thickness after 40 years of operation remained at 97.6 percent of the nominal thickness and confirmed that no significant degradation of the bottom of the CSTs was occurring.

Previous UT testing of the CST walls which are accessible from the exterior of the tank concluded that the tank sides are at or near nominal wall thickness. Based on the results, there is reasonable assurance that the existing programs are appropriate and the tanks will continue to perform their intended function for the period of extended operation.

3.1.2 Radwaste Discharge Line Direct investigations of the Radwaste Discharge Line included the following:

• Interior physical testing of the Radwaste Discharge Line included a dye study to assess for a potential leakage pathway from this subsurface pipe to the groundwater and monitoring well network.

Five pounds of Fluorescein dye mixture (75% dye equivalent, 25%

diluent) an environmentally safe dye to humans and aquatic life in the concentrations used for groundwater tracing work, was added to the shower room drain in January 2011. Additional water was added to fill the tank to nearly 500 gallons and discharge through the Radwaste Discharge Line. At the next scheduled discharge of radiological wastes in April 2011, Fluorescein dye was observed in the Discharge Channel, indicating that residual Fluorescein dye remained in the Radwaste

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 26 Discharge Line for approximately three months following dye introduction. As of the last date of samples collected during the dye study (19 March 2012), Fluorescein dye was not observed in down-gradient wells indicating that the Radwaste Discharge Line is intact and not a source of leakage into site groundwater.

• Exterior visual inspections of three separate locations of the Radwaste Discharge Line (4-HE-20) were completed by PNPS in November 2012, December 2012, and January 2013. Inspections were in accordance with the PNPS Underground Components Inspection Plan. Visual inspections of the pipe coating were performed. Based on PNPS observations, there were no issues found with the coating at each of the three locations. In addition to the visual inspection, ultrasonic testing was performed to assess the pipes thickness and no significant issues were identified.

3.1.3 Neutralization Sump and Discharge Pipe Direct investigations of the Neutralization Sump and Discharge Pipe included the following:

• An interior visual inspection of the 16,700 gallon concrete sump was performed in 2011 for potential leakage pathways to the environment.

The inspection identified minor repairs need in caulking around the sump wall and a structural beam at the top, as well as a small pit in the wall. No visual leak paths were observed and all penetrations were resealed at the end of the inspection.

An interior inspection of the discharge pipe using a camera borescope was originally planned for February 2013. During project planning activities associated with February 2013 inspection, it was determined that the interior assessment would need to be performed in May 2013 (i.e., a three month delay in the inspection). In March 2013, PNPS discovered a leak associated with the discharge pipe during a permitted release of tritium from the Neutralization Sump. A chronological summary of the details of the discharge activities, discovery of the leak and reporting activities associated with the leak is summarized below.

• 26 March 2013 - PNPS observes a leak of water inside the Reactor Building Auxiliary Bay, with discovery of the leak coinciding with an active discharge from the Neutralization Sump. Sampling of the leaking water, which was observed dripping from an electrical junction box, detected a chemical signature nearly equivalent to the

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 27 signature of the water inside the Neutralization Sump. The discharge event from the Neutralization Sump is immediately shut down.

• 27 March 2013 - Investigation activities by PNPS observe a slight depression in the ground surface over a buried section of the Neutralization Sump Discharge Pipe outside the Auxiliary Bay.

• 10 April 2013 - PNPS performs a camera borescope inspection of the interior section of the Neutralization Sump Discharge Pipe, specifically the section between CB10 and the Auxiliary Bay. The inspection notes the following observations:

o The discharge pipe is constructed of cast iron, with bell and spigot design connections between pipe sections; and o A separation in the pipe is observed at the location coinciding with the slight depression in ground surface.

• 10 April 2013 - PNPS reports a potential unmonitored release of radionuclides to NRC, MDPH, MassDEP and EPA. The discharge pipe is taken out of service.

• May 2013 - PNPS performs additional camera borescope inspections on the discharge pipe, including the entire section of buried pipe from the Auxiliary Bay to CB10, to CB11 and to the Discharge Channel.

Two additional separations in the pipe are noted in the section between the Auxiliary Bay and CB10. These two additional separations are communicated to NRC, MDPH, MassDEP and EPA.

The remainder of the discharge piping between CB10 and the Discharge Channel is determined to be intact and functional.

Based on the above findings, PNPS commences an internal investigation into the apparent/root cause of the pipe separation(s). The review concludes that there is no sufficient evidence to prove the specific failure mechanism. The review concludes that the pipe will be excavated at the three locations in order to allow a physical inspection of the pipe in order to assist in determining the primary cause of failure.

In July 2013, three excavations were completed over the discharge pipe located between the Auxiliary Bay and CB10. The excavations were performed by removing soil and visually inspecting the pipe with a borescope (camera), and exterior physical testing was completed by collecting soil samples below and adjacent to the pipe for radiological analysis. The excavations confirmed that only one location along the Neutralization Sump discharge pipe released radionuclides to soil. The confirmed location was consistent with the separation identified in the 10 April 2013 borescope inspection. Elevated concentrations of tritium and gamma emitting radionuclides were detected in soil at the point of release.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 28 In November and December 2013, monitoring wells MW-218 and MW-219 were installed immediately downgradient of the Neutralization Sump discharge pipe to assess whether the releases associated with the Neutralization Sump had impacted groundwater quality. The results of these investigations will be documented in future updates to the Logic Report.

Additional internal review of the discharge line from the Neutralization Sump indicated that this line was also used to convey make up water (a non-tritiated water source of water) generated inside the Auxiliary Bay.

Intermittent discharge of the makeup water through the discharge pipe indicates that the non-tritiated make up water would also have been released at the pipe separation, indicating that dilution of the released tritium likely occurred at the release point. The makeup water discharge was re-routed above ground to CB10, as the underground discharge pipe is out of service.

3.1.4 Main Stack Lines Direct investigations of the Main Stack Lines included the following:

• Interior physical testing of the Main Stack Drain Line (2-HE-20) was performed in August 2010 by a water injection test into the line and monitoring of resultant pressures. Two tests were performed. During the second test, no water was indicated to be flowing down the stack drain line prior to the test and pressure remained constant throughout the test. The tests showed variable results; however, the line did hold water pressure during the second test, concluding that the drain line is sound and intact. Based on the variable results of the test, additional field tests were performed to ensure the integrity of the 2-HE-20 line.

These are described below.

• Interior physical inspection of the Main Stack Building sump was completed in 2011. The sump, which is located at the base of the main stack, was found to be dry but actively in service. No leaks were observed that would attribute to a release of tritiated water from the sump.

• Exterior visual inspections of the Stack Drain Line (2-HE-20) were performed by PNPS following excavations of soil over the line. In December 2012, soil was excavated in the area where the Stack Drain Line exits the Main Stack Building. This inspection found that the line was in good condition. In August and September 2012, the Stack Drain Line was excavated at two locations adjacent to the Power Block,

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 29 including one west of the Auxiliary Building and one north of the Reactor Building. Each excavation was video recorded and the exposed section of the Stack Drain Line was inspected by PNPS staff.

Results indicate that the line is intact with no evidence of leakage at either of the two inspected locations. The protective wrapping around the line at the first excavation location appeared visually more intact than at the second where a section of the protective wrapping was potentially missing. However, in both locations, the soil around the Main Stack Drain Line was unsaturated, indicating that the SSC was not actively leaking at the two locations during the inspections. The integrity of repairs made to the Main Stack Drain Line during removal of the Salt Service Lines was not inspected during this evolution.

Exterior physical testing of the Stack Drain Line (2-HE-20) was completed during the August and September 2012 excavations by collecting soil samples from below and adjacent to the pipe for analysis of tritium. The soil samples were collected during the borescope inspection. Results indicate no contamination and therefore provided an additional line of evidence of the integrity of the line at these locations (ERM, 2012).3.1.5 Station Building Heating Lines Direct investigations of the Station Building Heating Lines included the following:

• Exterior visual inspection of the Station Building Heating Lines was performed in September 2012. A section of the line north of the Reactor Building was investigated in September 2012 by performing a vacuum excavation to remove overburden soil and to expose and visually inspect this line (ERM, 2012). The excavation and subsurface exposed section of the Station Building Heating Line was video recorded and visually inspected by PNPS staff. Results of the excavation and video inspection suggest that this SSC was not leaking at the inspected location.

• Exterior physical testing of the Station Building Heating Lines was completed in September 2012 by collecting soil samples from below and adjacent to the pipe for analysis of tritium. The soil samples were collected during the visual inspection activities. Results indicate no tritium was present and therefore provided an additional line of evidence of the integrity of the line at this location (ERM, 2012).

• Interior examination of the line in December 2012 was performed to determine if water was present within the air space developed by the corrugations on the Guard Pipe. No water was discovered in the

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 30 Guard Pipe, indicating that this pathway is not likely a source of leakage to groundwater.

3.1.6 Building Roof Drains Direct investigations of the Building Roof Drains and atmospheric deposition pathway include the following:

• Interior testing of the Reactor Building Roof Drain began in January 2011 with Eosine dye introduced into storm water junction box JB1 to simulate rainfall runoff from the Reactor Building Roof Drain. Five pounds of Eosine dye mixture (75% dye equivalent, 25% diluent), an environmentally safe dye to humans and aquatic life in the concentrations used for groundwater tracing work, was introduced to JB1 to simulate two separate situations; a low-flow storm event and a high-flow event. Following the dye introduction, some residual dye remained in the storm water drainage line until subsequent rainfall events further flushed the drainage system. As of the last date of samples collected during the dye study (19 March 2012), Eosine dye was not detected at down-gradient wells.

• Interior testing of the Radwaste Truck Loc Roof Drain began in January 2011 with Sulforhodamine B Dye introduced into storm water junction box JB3 to simulate two separate situations; a low-flow storm event and a high-flow event. Five pounds of Sulforhodamine B dye mixture (75% dye equivalent, 25% diluent), an environmentally safe dye to humans and aquatic life in the concentrations used for groundwater tracing work, was utilized for each test. Following the dye introduction, some residual dye remained in the storm water drainage line until subsequent rainfall events further flushed the drainage system. As of the last date of samples collected during the dye study (19 March 2012), Eosine dye was not detected at down-gradient wells.

3.2 GENERAL SITE EVALUATIONS 3.2.1 Monitoring Wells For all the above SSCs, indirect assessments included groundwater, surface water and rainwater monitoring to infer the integrity of SSCs. The monitoring data is routinely analyzed in order to develop potential correlations between observed data results and plant operations:

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 31

• Well monitoring - placement of monitoring wells down-gradient of SSCs to enable groundwater monitoring activities (i.e., groundwater sampling and water table elevations). A total of 22 groundwater monitoring wells have been installed to evaluate tritium in groundwater at the PNPS site. Wells are installed down-gradient of SSCs that contain tritium and have the potential for a release to groundwater. When elevated levels of tritium were identified in the wells, more frequent monitoring and new investigation wells were installed in an attempt to identify the source of the elevated tritium detection. Tritium has been historically identified at levels exceeding two times the minimum detectable activity (MDA) of approximately 400 pCi/L at wells MW-201, MW-205, MW-206, MW-209, MW-211, MW-215, and MW-216 (Figure 2). These priority wells are currently monitored on a more frequent basis, while the remaining site wells are monitored on a quarterly basis. The frequency of sampling at the priority wells has fluctuated over time, but generally consists of bi-weekly sampling activities. Weekly sampling has occurred at MW-205 when elevated detections were first detected at this well in 2010. Over time as the concentrations declined at MW-205, the frequency of monitoring at this well reduced to bi-weekly. PNPS is currently sampling select wells on a weekly basis, including MW-209, MW-211, MW-216, MW-218 and MW-219.

The PNPS Tritium Technical Team, supported by ERM, other contractors and with MDPH oversight, has led site activities associated with monitoring, identification, and reporting of site activities associated with groundwater protection and the source of elevated tritium concentrations.

• Data trend analysis - review of groundwater monitoring data trends to determine the traits and behavior of tritium trends in order to establish potential correlations with a source. Data trend analysis included:

o Review of tritium values and trends to determine nature and behavior of the source (i.e., one time release, intermittent release, constant release, and tritium concentrations (low, medium or high concentration)). In general, the highest tritium detections in groundwater were detected at wells MW-205 and MW-206. These elevated detections were reported in 2010, which represent the timeframe after each well was installed.

Since their peak values in 2010, the concentration of tritium at MW-205 and MW-206 have declined to levels that are well below their historic peaks. Groundwater trends at MW-205 and MW-206 indicate that concentrations generally fluctuate on a monthly basis. The observation of fluctuating concentrations

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 32 suggests that the sources are intermittent, and not a constant source or leak to groundwater. Based on the observed reduction in overall concentrations, it can be inferred that the activity or magnitude of the intermittent source has been reduced since 2010.

o Given the location of the Neutralization Sump Discharge Line relative to the groundwater flow regime west of the Power Block, the release associated with this system would contribute to the observed tritium levels at wells MW-211, MW-215, MW-209 and MW-205. The ability to link the historic tritium detections at these wells with past release(s) from the Neutralization Sump Discharge Pipe has not been ruled out.

This analysis is ongoing and requires incorporating assumptions, which may or may not reflect actual conditions associated with the release, and subsequent migration in groundwater. Since the discharge pipe has been taken out of service (for both future Neutralization Sump discharges and for releases of non-tritiated makeup water), the source of leakage is effectively eliminated, thereby preventing any future tritium to enter groundwater at this location, or that may have entered groundwater historically at this location. If the Neutralization Sump is the source of historic tritium levels at wells MW-211, MW-215, MW-209 and MW-205, the long-term monitoring trends at these wells should decline as the source is eliminated.

Any residual tritium between the wells and the release point would continue to migrate in groundwater, manifesting a concentration trend at the wells similar to the historic trends, respectively.

o The highest detections in groundwater are currently detected at MW-216 (maximum detection of tritium at 8,700 pCi/L).

Based on the hydrogeologic positioning of MW-216 and MW-206 and their positioning east of the deep foundations of the Power Block, the source of tritium at MW-216 and MW-206 is likely separate and distinct from the identified release on the west side of the Power Block.

o The monthly fluctuation in tritium concentrations at MW-205 and MW-206 were evaluated to assess for potential correlation tidal changes, lunar cycles and precipitation events. To date, no correlation between tritium concentrations and tidal, lunar (i.e.,

stage of full or new moon) or precipitation events have been identified in either of the wells.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 33

• Groundwater elevation (transducer) analysis - use of pressure transducers to record continuous groundwater elevations in select monitoring wells to identify potential anomalies in groundwater elevations that may record an intermittent leak, spill or change in plant operations. Transducers were positioned within existing monitoring wells between July and October 2010, and again in November 2013.

During the 2010 evaluation, only one anomaly was observed in MW-205, while several water level anomalies were identified at MW-206. In all cases, the anomaly is defined as an increase in groundwater elevation at the well that does not correspond with a precipitation event, and the increase in groundwater elevation was only recorded in the one well. To date, the sources of the groundwater elevation anomalies at MW-205 and MW-206 have not been defined. Results of the 2013 transducer survey will be documented in future updates to the Logic Report.

3.2.2 Rainwater Samples of rainwater were collected at various locations around the station and at an offsite location from August 2009 through August 2010, and a new study commenced in 2103. Results of the 2009-2010 survey indicated that tritium did not appear to be a component of precipitation at the Site, with most results being below the minimum detectable activity.

The highest tritium result was 669 pCi/L, which was collected from a sample within the vicinity of MW-203. Since tritium has been identified at numerous power plants at significantly higher values and that the release of tritium form the Reactor Building Vent averages 19,000 pCi/cubic meter of air, additional monitoring is being planned, and field methods re-assessed, to quantify this potential source to onsite monitoring wells.

Results of the current rainwater survey are underway and will be documented in future updates to the Logic Report.

3.2.3 Storm Water, Duct Banks & Surface Water Storm water manhole and junction box monitoring has involved the collection of samples of standing water in manholes and junction boxes which have generally been at levels that are less than the minimum detectable activity for tritium. However, detectable tritium as high as 1,500 pCi/L have been observed in select manholes. Additional monitoring is being planned, and methods re-assessed, to quantify this potential source to groundwater.

Electrical duct bank manhole monitoring samples involved the collection of standing water within electrical duct bank manholes. Tritium has

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 34 generally been at levels that are less than the minimum detectable activity (MDA) for tritium. However, detectable tritium as high as 4,500 pCi/L, has been observed in select manholes. Additional monitoring is being planned, and methods re-assessed, to quantify this potential source to groundwater.

Surface/bay water samples of ocean water are collected at two locations within the Intake Canal for radiological analysis. As previously indicated, these samples are collected consistent with MDPH recommendations and are used to ensure no offsite migration of the groundwater impacts. The location of one of these samples has consistently been collected at a location immediately downgradient of MW-205. The second sample has generally been collected at the entrance of the Intake Canal. Due to logistical and worker health and safety challenges associated with the collection of this second sample, the exact location has changed over time.

No tritium concentrations have been detected in any of the surface/bay water samples.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 35 4.0

SUMMARY

A summary of the logic rationale described above is presented in Table 3.

The individual categories used in the matrix table are defined as follows:

• Source Characteristics - a description of individual SSCs, their traits and behaviors:

o Concentration / Description - the concentration of tritium within the SSC and dimensions and/or volume of tritiated water within the SSC; o Usage Characteristics - a description of SSC usage during station operation; and o If Leakage, Expected Impact to Groundwater - a projection of the groundwater plume characteristics that would be observed in monitoring wells if the SSC had a leak to groundwater.

• SSC Inspection Methods - a description of testing activities to evaluate the integrity of each SSC:

o Direct Inspections - actual visual or physical tests performed on a SSC; and o Indirect Assessment - surveys or assessments performed on a SSC.

• SSC Inspection Results o Inspection Results - a determination of whether the SSC is contributing to elevated tritium levels in groundwater by considering the source characteristics of the SSC and results of SSC inspections; and o SSC Impact to Groundwater (GW) - an overall assessment on the SSC integrity based on the lines of direct and indirect inspection results.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 36

5.0 CONCLUSION

S To date, numerous site investigations and inspections have been performed to evaluate the potential for the release of tritium from SSCs at the PNPS site. The results of these investigations and inspections presented within the Logic Report conclude the following:

• Condensate Storage tanks and associated piping - based on both direct and indirect evaluations, the integrity of this system appears sound and there is no indication that either the storage tanks or subsurface piping are discharging to the environment.

• Radwaste Discharge Line - based on both direct and indirect evaluations, and according to groundwater reports to date, the Radwaste Discharge Line largely appears intact and does not provide a source of tritium to the site groundwater. In November 2013, well MW-4R was installed to replace MW-4 as a sentinel monitoring location for potential leaks from the Radwaste Discharge Line to migrate towards MW-216 and MW-206.

• Neutralization Sump and Discharge Pipe - the discharge pipe associated with the Neutralization Sump is a reported and confirmed release of radionuclides to soil. The discharge pipe was taken out of service in April 2013, and ongoing investigations are evaluating the impact of the pipe separation on groundwater quality, and connection with historical tritium detections in well MW-205. The source of leakage is effectively eliminated, thereby preventing any future tritium to enter groundwater at this location, or that may have entered groundwater historically at this location.

• Main Stack Lines - Based on direct and indirect evaluations performed to date, there is no indication that the Stack Drain Line is releasing tritium to the site groundwater.

• Reactor Building Vent - An evaluation of limited rainwater data indicates that atmospheric deposition is not a significant issue; however, additional samples will be obtained, and data collection methods re-assessed, based on industry experience to validate these results. A review of the storm water system, specifically through the application of dye into storm water junction boxes JB1 and JB3 indicates that these are not a source of tritium to the site groundwater.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 37

• Station Building Heating Systems - based on direct and indirect investigations, there is no indication that this system provides a source of tritium to the site groundwater.

• Electrical Duct Banks and Manholes - based on samples obtained to date, duct banks do not appear to be a significant source of tritium to groundwater. Additional monitoring will be performed of water found in these systems to verify the potential for accumulated storm water to be released to the site groundwater.

ERM ENTERGY - PILGRIM NUCLEAR POWER STATION - 0114809 MARCH 2014 38

6.0 REFERENCES

ERM, 2012. Summary of Pipe Inspection Activities, October 2012 MDPH, 2010. Status of Groundwater Monitoring Program at Pilgrim Nuclear Power Plant, 25 June 2010.

NEI, 2007. Industry Ground Water Protection Initiative - Final Guidance Document (NEI-07-07), 2007 NEI, 2010. Underground Piping and Tank Integrity (NEI 09-14), 2010 NRC, 2011. NRC Temporary Instruction 2515/185, 2011 NRC, 2012. List of Historical Leaks and Spills at U.S. Commercial Nuclear Power Plants. Revision 10, 2012 Town of Plymouth, 2011. Town of Plymouth Water Division, Annual Water Report, Reporting Year 2011

Tables

Table 1 Summary of Monitoring Well Location and Construction Data Entergy Pilgrim Nuclear Power Station 600 Rocky Hill Rd, Plymouth, MA Bottom Top MW-201 15-Nov-2007 Functional Downgradient Power Block 21.22 20.87 2

PVC 15 25

-4.13 10.87 Construction Backfill MW-202 6-Nov-2007 Functional Downgradient Condensate Tanks 21.33 20.89 2

PVC 15 24

-3.11 11.89 Construction Backfill MW-202I 29-Apr-2010 Functional Downgradient Condensate Tanks and Piping 21.32 20.97 2

PVC 5

45

-24.03

-19.03 Deeper Sand MW-203 5-Nov-2007 Abandoned Upgradient Buried Lines to Main Stack at the Base of Hill 22.61 24.89 2

PVC 15 22 2.89 17.89 Sand MW-204 5-Nov-2007 Functional Adjacent to Discharge Channel 21.79 21.51 2

PVC 15 23

-1.49 13.51 Construction Backfill MW-205 28-Apr-2010 Functional Downgradient Condensate Tanks and Piping 21.44 21.04 2

PVC 10 25

-3.96 6.04 Construction Backfill MW-206 28-Apr-2010 Functional Downgradient Buried Components of Rad Waste Building 22.65 22.28 2

PVC 10 25

-2.72 7.28 Construction Backfill MW-207 26-Apr-2010 Functional Downgradient AOG, Gland Seal, and Liquid Radioactive Waste Discharge Piping 22.76 22.28 2

PVC 10 22 0.28 10.28 Construction Backfill MW-208S 27-Apr-2010 Functional Upgradient Power Block 30.24 33.43 2

PVC 10 25 8.43 18.43 Shallow Sand MW-208I 27-Apr-2010 Functional Upgradient Power Block 30.21 33.08 2

PVC 5

42

-8.92

-3.92 Deeper Sand MW-209 10-Aug-2010 Functional Downgradient Primary Vent Stack Drain Line 22.85 22.60 2

PVC 10 25

-2.40 7.60 Construction Backfill MW-210 10-Aug-2010 Functional Adjacent to Condensate Tanks 22.64 22.10 2

PVC 10 25

-2.90 7.10 Construction Backfill MW-211 11-Aug-2010 Functional Downgradient Neutralization Sump Discharge Line 22.82 22.50 2

PVC 10 24

-1.50 8.50 Construction Backfill MW-212 11-Aug-2010 Functional Downgradient AOG, Gland Seal and Liquid Radioactive Waste disharge piping 21.52 20.98 2

PVC 10 24

-3.02 6.98 Construction Backfill MW-213 12-Aug-2010 Functional East of Power Block 22.21 21.94 2

PVC 10 25

-3.06 6.94 Shallow Sand MW-214 9-Aug-2010 Functional East of Power Block 22.22 21.92 2

PVC 10 25

-3.08 6.92 Shallow Sand MW-3 2-Jul-1987 Functional South of Rock Hill Road at PNPS Leach Field NM 65.24 2

PVC 15 60 5.24 20.24 Sand MW-4 31-Jul-1997 Abandoned SE Corner of Turbine Building and Downgradient of Liquid Radioactive Waste Discharge Piping 23.25 23.28 1.75 Steel 10 24

-0.72 9.28 Construction Backfill MW-215 9-Dec-2011 Functional Downgradient of Reactor Bldg Deep Foundation 23.08 22.71 2

PVC 10 25

-2.29 7.71 Construction Backfill MW-216 6-Sep-2012 Functional NE Corner of Radwaste Building and Downgradient of Deep Foundation 22.76 22.48 2

PVC 10 24

-1.52 8.48 Construction Backfill MW-217 12-Dec-2011 Functional SW Corner of Turbine Building and Downgradient AOG, Gland Seal, and Liquid Radioactive Waste Discharge Piping 22.94 22.62 2

PVC 10 22 0.62 10.62 Construction Backfill MW-4R 11-Nov-2013 Functional SE Corner of Turbine Building and Downgradient of Liquid Radioactive Waste Discharge Piping 23.19 22.61 2

PVC 10 25

-2.39 7.61 Construction Backfill MW-218 13-Nov-2013 Functional Adjacent to Auxiliary Bay and Downgradient of Neutralization Sump 23.03 22.42 2

PVC 10 24

-1.58 8.42 Construction Backfill MW-219 10-Dec-2013 Functional Adjacent to CB10 22.10 21.51 2

PVC 10 25

-3.49 6.51 Construction Backfill Notes All elevations are relative to NGVD 1929 datum MP = Measuring Point NM = Not Measured Hydrogeologic Position Relative to Site System, Structure or Infrastructure (SSC)

Ground Surface Elevation (feet)

MP Elevation (feet)

Existing Wells Well Diameter (inches)

Well Material Screen Length (feet)

Constructed Well Depth (feet below ground)

Screen Interval Elevation (feet)

Geologic Unit Monitored Well Designation Date Installed Well Condition for Monitoring

Table 2 Monitoring Well Tritium Results (pCi/L)

Entergy - Pilgrim Nuclear Power Station 600 Rocky Hill Rd, Plymouth, MA Date MW-201 MW-205 MW-206 MW-209 MW-211 MW-215 MW-216 MW-218 MW-219 MW-4R MW-217 MW-202 MW-202-I MW-203 MW-204 MW-207 MW-208-S MW-208-I MW-210 MW-212 MW-213 MW-214 WWTP MW-3XFMR-MW4 29-Nov-2007 3300 733 NDA 1586 22-Jan-2008 2409 572 444 796 635 24-Apr-2008 1332 976 525 899 758 917 17-Jul-2008 1875 622 461 808 NDA 979 08-Oct-2008 1784 574 455 850 NDA 547 18-Mar-2009 1292 688 681 774 498 627 27-May-2009 1205 615 419 959 NDA 734 23-Sep-2009 1726 757 663 1004 NDA 818 15-Dec-2009 987 919 632 875 NDA 623 02-Mar-2010 1180 1040 900 930 360 590 17-May-2010 910 5810 1470 900 930 1060 1230 1090 630 380 500 830 11-Jun-2010 8632 589 NDA 21-Jun-2010 11072 660 529 30-Jun-2010 8477 499 520 07-Jul-2010 718 25552 3352 553 471 447 759 488 NDA NDA NDA 568 15-Jul-2010 6870 589 425 22-Jul-2010 731 12600 1520 390 473 26-Jul-2010 932 10800 2030 580 408 02-Aug-2010 576 17800 1380 579 NDA NDA 794 512 NDA NDA NDA 504 09-Aug-2010 961 12700 4550 349 390 480 578 394 381 NDA NDA 491 17-Aug-2010 1090 7840 5370 371 NDA 712 805 701 NDA NDA NDA 759 26-Aug-2010 873 7960 10500 2940 1540 364 485 423 383 453 NDA NDA 1280 514 NDA NDA NDA 557 30-Aug-2010 974 1390 2790 1780 1340 NDA NDA NDA 403 421 NDA NDA NDA 385 NDA NDA NDA 573 07-Sep-2010 1200 3010 3190 1560 1570 352 417 375 455 329 NDA NDA 589 655 341 NDA NDA 662 13-Sep-2010 1510 1840 6830 1590 1730 461 652 NDA 415 NDA NDA NDA 641 618 NDA NDA NDA 398 20-Sep-2010 1340 22000 8290 1390 1200 NDA 341 NDA NDA NDA NDA NDA 1020 462 NDA NDA NDA 493 27-Sep-2010 958 25000 5040 1760 1090 400 522 NDA 596 519 NDA 413 816 513 438 NDA 400 645 04-Oct-2010 1140 17300 8210 12-Oct-2010 1040 1760 10100 1440 1180 NDA NDA NDA 646 NDA NDA NDA 610 455 415 NDA NDA 466 18-Oct-2010 966 5890 5950 25-Oct-2010 1340 2840 12200 1710 870 NDA NDA NDA 532 NDA NDA NDA 837 568 NDA NDA NDA 556 01-Nov-2010 1020 16700 13600 15-Nov-2010 909 5730 9250 1830 1050 NDA NDA NDA 529 NDA NDA NDA 1230 745 NDA NDA NDA 491 22-Nov-2010 1290 1810 4720 29-Nov-2010 1060 1960 5290 1550 717 NDA NDA NDA 526 NDA NDA NDA NDA 533 NDA NDA NDA 607 09-Dec-2010 1150 2300 5270 14-Dec-2010 781 17800 10300 1940 1250 579 486 NDA 503 NDA NDA NDA 1090 620 NDA NDA 534 740 29-Dec-2010 1190 3930 8950 1870 1110 579 556 930 830 04-Jan-2011 875 1410 4360 10-Jan-2011 928 2430 3700 1370 927 308 365 NDA 375 589 NDA NDA 769 583 NDA NDA NDA NDA 17-Jan-2011 928 7240 3450 25-Jan-2011 647 830 3820 1010 763 NDA NDA NDA NDA 582 NDA NDA 520 415 NDA IA IA NDA 31-Jan-2011 704 1080 07-Feb-2011 768 1060 2500 1280 NDA NDA NDA NDA 648 NDA NDA 529 628 NDA IA NDA NDA 14-Feb-2011 499 10900 2650 22-Feb-2011 446 1330 3640 1130 956 01-Mar-2011 546 9080 1990 758 856 NDA NDA NDA 547 438 NDA NDA 421 578 NDA NDA NDA NDA 08-Mar-2011 592 1080 2700 1240 1170 15-Mar-2011 477 5470 2320 1320 940 22-Mar-2011 712 1460 3600 1030 1020 29-Mar-2011 546 4250 1750 985 1010 384 NDA NDA NDA 467 NDA NDA 484 IA 385 NDA NDA NDA 05-Apr-2011 454 5190 Lost Lost 1070 IA 12-Apr-2011 324 6320 975 1030 1450 19-Apr-2011 NDA 921 1560 932 973 27-Apr-2011 695 2630 2090 979 1120 NDA NDA NDA NDA 494 NDA NDA NDA NDA NDA NDA NDA NDA 03-May-2011 461 5680 905 1040 970 11-May-2011 529 13400 1840 1070 1410 19-May-2011 NDA 1920 2430 898 921 24-May-2011 422 1790 1110 908 835 NDA NDA NDA NDA NDA NDA NDA 429 569 NDA NDA NDA NDA 02-Jun-2011 342 5340 975 1030 1250 07-Jun-2011 422 9250 1230 923 1120 15-Jun-2011 362 6710 1250 1060 1040 21-Jun-2011 399 1950 620 1080 979 NDA 322 NDA NDA 521 NDA NDA 312 428 377 NDA NDA NDA 28-Jun-2011 541 7900 953 969 IA

Table 2 Monitoring Well Tritium Results (pCi/L)

Entergy - Pilgrim Nuclear Power Station 600 Rocky Hill Rd, Plymouth, MA Date MW-201 MW-205 MW-206 MW-209 MW-211 MW-215 MW-216 MW-218 MW-219 MW-4R MW-217 MW-202 MW-202-I MW-203 MW-204 MW-207 MW-208-S MW-208-I MW-210 MW-212 MW-213 MW-214 WWTP MW-3XFMR-MW4 07-Jul-2011 585 3330 1750 948 949 13-Jul-2011 542 3240 804 970 803 19-Jul-2011 588 1710 845 1160 847 NDA 337 345 470 NDA NDA 359 461 640 450 NDA NDA 451 27-Jul-2011 572 9100 1220 736 1030 02-Aug-2011 NDA 2520 1840 669 626 09-Aug-2011 529 5320 1380 833 1240 16-Aug-2011 557 4730 NDA 729 1150 NDA NDA NDA NDA 427 NDA NDA NDA 503 NDA NDA NDA NS 23-Aug-2011 685 7330 953 1320 1330 30-Aug-2011 653 2140 2280 879 1380 06-Sep-2011 IA 1500 2010 1120 IA 13-Sep-2011 399 1190 1400 1060 1290 NDA NDA NDA NDA NDA NDA NDA 397 402 NDA NDA NDA NS 19-Sep-2011 600 1890 2970 1370 1240 27-Sep-2011 493 4650 3740 1570 1270 04-Oct-2011 IA 2040 2650 1520 1720 11-Oct-2011 618 7110 1950 1280 1620 NDA 483 373 NDA NDA 322 341 664 792 333 NDA NDA NDA 18-Oct-2011 533 4340 1590 1170 1370 25-Oct-2011 512 4900 1400 1160 1130 01-Nov-2011 IA 712 1110 1240 1290 08-Nov-2011 661 3840 3380 1450 1790 NDA NDA NDA NDA NDA NDA NDA 782 685 NDA NDA NDA 15-Nov-2011 967 2880 1960 1180 1010 22-Nov-2011 IA 6790 3050 1080 1260 29-Nov-2011 413 3530 3060 1180 1320 06-Dec-2011 NDA 6860 3730 1010 1200 13-Dec-2011 419 2550 5050 1290 1330 22-Dec-2011 454 5390 3330 1570 1420 1820 542 29-Dec-2011 348 2380 3610 1210 1240 1330 530 04-Jan-2012 348 7570 2420 967 1290 1480 442 10-Jan-2012 407 4990 2890 967 1170 1320 NDA 19-Jan-2012 582 5780 2830 1180 1250 1440 504 24-Jan-2012 646 2500 3250 938 852 1390 434 07-Feb-2012 NDA 8400 2890 933 1200 1170 492 21-Feb-2012 707 4380 2180 1200 1380 1600 901 06-Mar-2012 514 5090 2480 1250 1220 1490 517 942 NDA NDA NDA 447 NDA NDA 1080 534 NDA NDA NDA 408 20-Mar-2012 NDA 2260 1440 769 951 1200 520 03-Apr-2012 NDA 6940 2360 1050 1230 1310 494 17-Apr-2012 780 3860 1930 1010 1590 1320 695 02-May-2012 674 5440 IA 1030 1230 1730 660 15-May-2012 592 1820 IA 985 1140 1200 666 29-May-2012 629 5760 1550 887 1190 1470 462 19-Jun-2012 554 6440 1010 1050 1130 900 865 28-Jun-2012 985 541 NDA NDA 488 NDA NDA 1010 NDA NDA NDA 421 11-Jul-2012 648 1220 1240 889 1360 1360 NDA 26-Jul-2012 2310 4220 977 1111 1310 1230 925 07-Aug-2012 616 1180 1480 907 826 1210 657 22-Aug-2012 438 1670 1320 696 866 1090 657 871 NDA NDA NDA 537 NDA NDA 738 NDA NDA NDA 419 07-Sep-2012 NDA 1400 1080 800 951 831 526 20-Sep-2012 438 2260 1640 1060 901 1060 3150 440 26-Sep-2012 3230 03-Oct-2012 NDA 1050 1080 613 704 1050 2250 436 09-Oct-2012 2670 17-Oct-2012 NDA 1900 1360 584 985 1110 4800 424 25-Oct-2012 4430 01-Nov-2012 407 3520 4300 864 1040 1030 7620 485 06-Nov-2012 3060 15-Nov-2012 551 1210 1510 714 1070 1070 2460 NDA 1160 NDA NDA NDA NDA NDA NDA 844 IA NDA NDA NDA 696 21-Nov-2012 3670 29-Nov-2012 NDA 3680 1970 810 986 1010 3960 NDA 04-Dec-2012 3740 14-Dec-2012 NDA 1040 2820 928 685 1220 5540 21-Dec-2012 5430 27-Dec-2012 507 3510 3670 669 1230 1130 5240 04-Jan-2013 2870 11-Jan-2013 479 657 1940 828 1070 1130 2440 17-Jan-2013 4580 24-Jan-2013 NDA 1090 2000 765 1090 1110 3650 29-Jan-2013 4000

Table 2 Monitoring Well Tritium Results (pCi/L)

Entergy - Pilgrim Nuclear Power Station 600 Rocky Hill Rd, Plymouth, MA Date MW-201 MW-205 MW-206 MW-209 MW-211 MW-215 MW-216 MW-218 MW-219 MW-4R MW-217 MW-202 MW-202-I MW-203 MW-204 MW-207 MW-208-S MW-208-I MW-210 MW-212 MW-213 MW-214 WWTP MW-3XFMR-MW4 07-Feb-2013 447 2020 3590 824 1250 1120 5410 14-Feb-2013 4940 20-Feb-2013 481 851 1350 886 1080 796 1430 492 1010 644 NDA NDA NDA NDA NDA 1580 560 NDA NDA NDA 607 01-Mar-2013 4020 07-Mar-2013 479 692 1470 879 972 3570 11-Mar-2013 799 2610 20-Mar-2013 540 722 405 977 1340 1020 1780 28-Mar-2013 1120 03-Apr-2013 NDA 533 459 888 841 630 11-Apr-2013 1180 1960 18-Apr-2013 Inaccessible 354 433 729 1010 851 699 23-Apr-2013 1890 26-Apr-2013 NDA 1370 30-Apr-2013 NDA 701 503 592 1420 1090 1690 09-May-2013 1200 2680 13-May-2013 NDA 1630 426 700 1040 805 2730 429 923 614 NDA NDA NDA NDA NDA 649 419 NDA NDA NDA 525 21-May-2013 935 3450 28-May-2013 NDA 389 NDA 459 959 587 3710 04-Jun-2013 424 665 4270 10-Jun-2013 NDA 1550 410 851 1280 901 6400 17-Jun-2013 666 1080 5460 25-Jun-2013 NDA 401 NDA 644 859 913 3020 01-Jul-2013 473 953 3670 08-Jul-2013 NDA 3080 NDA NDA 829 753 4200 16-Jul-2013 1010 1310 2300 22-Jul-2013 NDA 1190 NDA 672 849 647 3790 29-Jul-2013 637 1400 3660 05-Aug-2013 NDA NDA NDA 590 1120 1130 4690 13-Aug-2013 893 1120 4290 20-Aug-2013 NDA NDA NDA 461 1070 1040 3820 27-Aug-2013 NDA NDA NDA 470 1090 998 4360 NDA 393 474 NDA NDA NDA NDA 552 NDA NDA NDA NDA 762 03-Sep-2013 465 802 5590 10-Sep-2013 NDA NDA NDA 797 1350 1130 3330 17-Sep-2013 692 672 5720 24-Sep-2013 NDA 451 NDA 659 912 872 6230 01-Oct-2013 813 900 6460 08-Oct-2013 NDA NDA NDA 1020 1170 1010 5820 15-Oct-2013 895 1060 5430 22-Oct-2013 NDA 599 NDA 818 1180 809 4960 29-Oct-2013 NDA 431 NDA 711 937 861 3850 325 NDA 833 NDA NDA NDA NDA 428 NDA NDA NDA NDA 460 04-Nov-2013 NDA 578 552 1050 944 1170 7800 18-Nov-2013 NDA 700 1670 920 1070 1260 8700 4590 564 25-Nov-2013 1260 1010 3920 5810 616 02-Dec-2013 NDA 669 908 1370 1580 1450 6140 4220 724 11-Dec-2013 1120 1250 4680 3950 2120 555 Notes:

All sample results in picocuries (pCi) per liter (L)

IA = Inaccessable during well sampling event NDA = No Detectable Activity NS = Not Sampled

Table 3 PNPS SSC Investigations and Results Entergy - Pilgrim Nuclear Power Station 600 Rocky Hill Rd, Plymouth, MA Concentration/Description UsageCharacteristics IfLeakage,ExpectedImpactto Groundwater DirectInspections IndirectAssessments InspectionResults SSCImpacttoGW?

CondensateStorageTanks (CSTs)andassociatedpiping sourceofstationmakeupwater andprovidingcondensatewater forpowergeneration Two275,000gallontanks 8,000,000pCi/L Subsurfacepiping(4inchto18 inch)toReactorBldg.

ContinuoususeduringPNPSoperation.Coated carbonsteeltanksequippedwithinletandoutlet lines,transferpumpsandassociatedpipingandvalves (i.e.,"valvepit").

Bothtanksaretypicallyfullwithcondensatewater Highstableconcentrationseven atlowleakrates(i.e.steadystate plume) 1.Guidedwaveultrasonictesting ofsubsurfacepiping(2010) 2.RhodamineWTdyeaddedto drainwithinCSTvalvepit(2011) 3.Interiorvisualinspectionand ultrasonicthickness(UT)testing oftank(2012) 4.Quarterlyexteriorvisual inspections Noelevatedtritiumdetections atdowngradientwells(MW 210,MW202S,orMW202I)

ConcentrationsatMW205are intermittentratherthansteady state,andoverallreductionin concentrationtrendsis inconsistentwithexpectedleak fromCST CSTtanksandburiedpiping componentspassedphysical testing.

NodetectionofRhodamineWT addedtovalvepitindown gradientmonitoringwells Noindicationofanactiverelease togroundwater RadwasteDischargeLine primarylinefordischarging permittedradiologicalreleaseto theDischargeChannel variableconcentrationsbased onplanneddischarges dischargesapproximatelyonce peryear subsurfacepiping(4inchpipe) fromsouthsideTurbineBldg.to DischargeChannel 2007:nodischarges 2008:nodischarges 2009:3dischargestotaling54,000gal.

2010:5dischargestotaling82,200gal.

2011:8dischargestotaling138,800gal.

2012:nodischarges 2013:Nodischarges(throughJuly)

Highconcentrationswith intermittency(followingschedule ofdischarge) 1.Fluoresceindyeaddedto dischargeline(2011) 2.Exteriorvisualinspectionsat threeseparatelocationsin November2012,December 2012,andJanuary2013 Noelevatedtritiumdetections atdowngradientwellsMW4, MW207,MW217,MW211, MW212,MW209,MW215and MW204 Timingandtrendofdetections atMW205,MW216andMW 206donotcorrelatewith historicaldischargesthroughthe RadwasteDischargeLine NodetectionofFluorescein addedtoRadwasteDischarge Lineindowngradientmonitoring wells Noindicationofanactiverelease togroundwater NeutralizationSumpDischarge sumptoreceive,storeandtreat waterfromAuxBaypriorto dischargethroughstormwater drainagesystem 16,700gallonconcretesump subsurfacepiping(4inch)to stormwatercatchbasin#10 variableconcentrationsbased onprocessedeffluent 0to20dischargesperyear dischargepipealsoconveysnon tritatedmakeupwateronan intermittentbasis 2007:3dischargestotaling28,380gal.

2008:nodischarges 2009:1dischargetotaling10,340gal.

2010:1dischargetotaling8,016gal.

2011:20dischargestotaling187,770gal.

2012:5dischargestotaling47,600gal.

2013:(throughApril):4dischargestotaling38,410 gal.

Highconcentrationswith intermittency(followingschedule ofdischarges)

Possibledilutionoftritiumgiven dischargepipe'susefor conveyingnontritiatedmakeup water 1.Interiorvisualinspectionof sump(2011)

Interiorvisual(borescope) inspectionsofdischargepipe (2013)

Exteriorvisual(borescope) inspectionsandsoilsamplingat threelocationsbetweenAuxiliary BayandCB10(2013)

Noelevatedtritiumdetections atdowngradientwellsMW211, MW215andMW209 MW218andMW219installed inNovember/December2013to assesstheconfirmedreleases andimpacttogroundwate quality Novisualleakpathwaywas observedduringinteriorsump inspection Oneseparationinthedischarge lineconfirmedasourceof releasetosoil Noindicationofanactiverelease togroundwater Ongoinginvestigationsto evaluatetheimpactofthepipe separationongroundwater quality,andconnectionwith historicaltritiumdetectionsat MW205 StackDrainLinesapiping bundleconveyingoffgastothe PrimaryStackanddrainagedown totheReactorBldg.sump Subsurfacepipingbundle consistingof:

40"GD8(OffGasDuctLine) 16"HE15(GlandSealHoldup Line) 20"HE44(VentDuctLine) 2"HE34(LoopSealLine) 2"HE20(MainStackDrainLine)

SubsurfacepipingfromSouth sideTurbineBldg.(PowerBlock) toMainStackandreturnsto ReactorBldg.

ContinuoususeduringPNPSoperationofalllines betweenPowerBlockandMainStack.

Linesmaybeisolatedduringrefuelingoutage.

Highconcentrationswithstable trends(i.e.steadystateplume) 1.Pressureteston2"HE20 (2010) 2.Inspectionofsumpanddrain atbaseoftheMainStack(2011) 3.Exteriorvisual(camera) inspectionsattwolocations (2012) 4.Soilsamplingattwolocations alongthe2"HE20drainline (2012)

Noelevatedtritiumdetections atwellsMW211,MW209and MW215 ConcentrationsatMW205are intermittentratherthansteady state Pressureteston2"HE20 indicatevariableresultsheld pressureduringsecondtest.

Exteriorvisualinspectionof2" HE20lineindicatesno deterioration Soilsamplesadjacentto2"HE 20linedidnotdetecttritium Noindicationofanactiverelease togroundwater SourceCharacteristics SSCInspectionMethods SSCInspectionResults System,Structure,Component orWorkPractice

Table 3 PNPS SSC Investigations and Results Entergy - Pilgrim Nuclear Power Station 600 Rocky Hill Rd, Plymouth, MA Concentration/Description UsageCharacteristics IfLeakage,ExpectedImpactto Groundwater DirectInspections IndirectAssessments InspectionResults SSCImpacttoGW?

SourceCharacteristics SSCInspectionMethods SSCInspectionResults System,Structure,Component orWorkPractice ReactorBuildingVent (AtmosphericDeposition) gaseousdischargepathwayfrom AuxiliaryBay locatedatSWcornerofReactor Bldg.

ContinuousgaseousdischargesduringPNPS operation Oncedischargedtotheatmosphere,gaseoustritium canbepotentiallywashedoutduringprecipitation events,resultinginlocalizedrainwaterhavingelevated tritium Variableconcentrationsin rainwateronlyduring precipitationevents Rainwaterwouldneedto infiltratedowntogroundwater Detectionsinrainwaterand groundwaterindownwind directionofstationventduring specificweatherevent 1.Collectionofrainwater samplesacrosssite 2.Collectionofrainwater samplesonReactorBldg.roof 3.Eosinedyeaddedtocatch basinJB1(ReactorBldg.roof drain) 4.SulforhodamineBdyeadded tocatchbasinJB3(roofdrain fromRadwasteBldg.TruckLoc Bldg.)

Noelevatedtritiumdetectedin rainwaterorcatchbasinsamples.

FrequencyofdetectionsatMW 205,MW206andMW216do notcorrelatewithrainfallevents.

Dyeintroducedtocatchbasins wasnotdetectedingroundwater samples.

Trendemergingrelatedto concentrationfluctuationsat MW209,MW206andMW216 Noelevatedtritiuminpast rainwaterprecipitationsamples Noelevatedtritiuminpast stormwatersamples NodetectionofEosinedyein monitoringwells NodetectionofSulforhodamine Bdyeinmonitoringwells Nocurrentindicationofanactive releasetogroundwater Additionalprecipitationanalysis tobeperformed HistoricSpillsdocumented tritiumspillsinplant10CRF 50.75(g)files Variableconcentrationsof tritium HistoricTritiumSpillEvents 1976ResinSpillyardarea 1977LiquidSpillRadwasteTruckLoc 1981ResinSpillWestofReactorBldg.

1982ResinSpillReactorBldg.

1988LiquidSpillRadwasteTruckLoc Residuallevels(ifany)resulting inlow,butelevatedbaseline levelsingroundwater 1.Collectionofsoilsamplesat historicspilllocation WellsMW201,MW202,MW 205andMW206downgradient ofhistoricspills Observationofintermittent levelsoftritiumatMW205and MW206arenotconsistentwith aresidualsourcesuchasa historicspill.

Noelevatedtritiuminsoil detectedinsoilsamplescollected nearhistoricspilllocations.

Noindicationofconnectionto theintermittentlevelsobserved atMW205andMW206.

Historicspillsmaycontributeto elevatedbaselinelevelsinwells westofthePowerBlock.

StationHeatingSystem&Guard Pipeburiedpipingbundle deliveringhotwaterforstation heating two6inchdiameterpipes surroundedbyconcretewithina largercorrugatedorguardpipe Potentialfortritiatedwatervaportoenterand condensewithinGuardPipeandleaktogroundwater Lowconcentrationswith intermittency(weather dependent) 1.Exteriorvisualinspection (2012) 2.Inspectionforpresenceof waterinsidetheguardpipe (2012)

MW205andMW202Sand MW202Iaremonitoreddown gradientoftheStationHeating SystemandGuardPipe Nowaterdetectedwithinthe GuardPipe Novisualleakagepathwaywas observedduringexterior inspection Nosourceofwaterforleakage ElectricalDuctBankLines&

ManholesAppendixRductlines Variableconstructionformats anddiametersincluding reinforcedconcretestructures, concrete/steelpipingsystems Potentialfortritiatedrainwatertoenterelectricduct bankmanholesandflowalongductlines Variableconcentrationswith intermittency(weather dependent) 1.Collectionofsamplesfrom withinductbankmanholes MW205,MW202S/I,MW206, MW209,andMW216aredown gradientofElectricDuctBank system Historicmonitoringindicatedno consistentelevatedlevelof tritiuminelectricmanholes Nocurrentindicationofanactive releasetogroundwater Additionalevaluationstobe performedofstormwaterwithin ductbanks

Figures

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(c) 2009 Microsoft Corporation and its data suppliers. Image acquired 2007.

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Legend Monitoring Well Location A

Figure 2 - Site Plan S103 S106 S10 S12 S11 S107 S108 S109 S110 S104 S105 S102 S14 S113 S3 S2 S1 S101 S5 S7 S4 S16 S13 S9 S17 S15 S8 Facilities Key Process Facilities S1 - Reactor Building S2 - Turbine Building S3 - Radwaste Building S4 - Emergency Diesel Generator (EDG) Building S5 - Intake Structure S6 - Breakwater S7 - Discharge Structure S8 - Main Stack Building S9 - Off Gas Retention Building S10 - Blackout Emergency Diesel Generator Building S11 - Security Diesel Generator Building S12 - Switchyard and Terminal House S13 - Retube Building / HP Support Facility S14 - Trash Compacting Facility S15 - Sewage Treatment Facility S16 - Hydrogen Generation Building S17 - Sludge Dewatering Facility S18 - Auxilary Bay Administrative Facilities S101 - Former Executive Building S102 - Operations and Maintenance Building S103 - Indoctrination and Support Building S104 - Fitness for Duty Building S105 - Engineering and Plant Support Building S106 - Secondary Access Point S107 - Central Alarm Station S108 - Warehouse / Shops S109 - Office / Warehouse S110 - Contractor Office / Warehouse / Shops S111 - 200' Pine Hills Radio Tower (Not Shown)

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(c) 2009 Microsoft Corporation and its data suppliers. Image acquired 2007.

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Figure 5 - Site Layout Radwaste Discharge Line Neutralization Sump Discharge Line Main Stack Lines Note: Line locations are approximate Legend NEI 07-07 Groundwater Protection Initiative Monitoring Well Surface Water Sample Location A

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