ML21027A242

General Electric, (Ge), Ltr. Dated December 11, 2020, W/Enclosure, Unc, Inc., Final Status Survey Report

ML21027A242
Person / Time
Site:	07000371
Issue date:	12/11/2020
From:	Van Nortwick J General Electric Co
To:	Masnyk-Bailey O Division of Nuclear Materials Safety I
References
Download: ML21027A242 (59)

Text

GE Global Operations, Environment, Health & Safety James W Van Nortwick, Ph.D., PE Technical Environmental Engineering Expert T 312.513.4588 December 11, 2020 james.vannortwick@ge.com 3726 North Wayne Avenue Chicago, IL 60613 Ms. Orysia Masnyk Bailey U.S. Nuclear Regulatory Commission Division of Nuclear Material Safety 2100 Renaissance Boulevard King of Prussia, PA 19406

Subject:

Former United Nuclear Corporation Facility 71 Shelton Avenue, New Haven, Connecticut Final Status Survey

Dear Ms. Masnyk Bailey:

General Electric (GE) is pleased to submit the attached Final Status Survey (FSS) for the former United Nuclear Corporation Facility located at 71 Shelton Avenue, New Haven Connecticut. We believe the FSS demonstrates that the site can be released for unrestricted use as per the guidance provided in the Multi-Agency Radiation Survey and Site Investigation Manual MARSSIM (NUREG-1575) and look forward to your concurrence.

Please contact me with any comments or concerns.

Sincerely, James W. Van Nortwick, Ph.D., PE Copies:

Anthony Dimitiradis, NRC Greg Chandler, DOE David Delwiche, DOE Jeff Semancik, CTDEEP Michael Firsick, CTDEEP Rocco Giampaolo, Arcadis Les Skoski, Arcadis

Enclosure:

1. Final Status Survey- Former United Nuclear Corporation, Naval Products Facility, New Haven, Connecticut

General Electric Company FINAL STATUS SURVEY REPORT Former United Nuclear Corporation Naval Products Facility New Haven, Connecticut December 2020

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation CONTENTS Acronyms and Abbreviations...................................................................................................... iii 1 Introduction ......................................................................................................................... 1 1.1 Background ................................................................................................................... 1 1.2 Previous Investigations ................................................................................................. 3 1.3 2019 Cleanup Plan ........................................................................................................ 5 2 Data Quality Objectives....................................................................................................... 7 2.1 State the Issue .............................................................................................................. 7 2.2 Identify the Decision ...................................................................................................... 7 2.3 Inputs into the Decision ................................................................................................. 7 2.3.1 Radionuclides of Concern ..................................................................................... 8 2.3.2 Derived Concentration Guideline Level ................................................................. 8 2.4 Define the Study Boundaries ......................................................................................... 9 2.5 Data Collection Method ................................................................................................. 9 2.5.1 Minimum Detectible Concentration ....................................................................... 9 2.6 Define Acceptable Limits on Decision Errors ................................................................10 2.6.1 Null and Alternative Hypotheses ..........................................................................10 2.6.2 Relative Shift........................................................................................................11 3 Survey Criteria ...................................................................................................................12 3.1 Release Criteria ...........................................................................................................12 4 Survey Units ......................................................................................................................13 4.1 Class 1 Survey Units ....................................................................................................14 4.2 Class 2 Survey Unit ......................................................................................................15 4.3 Class 3 Survey Unit ......................................................................................................15 4.4 Argyle Street Sewer .....................................................................................................15 4.5 Background Radioactivity .............................................................................................16 5 Sampling ............................................................................................................................17 5.1 Number of Sample Locations .......................................................................................17 arcadis.com i

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 5.2 Soil Sample Collection .................................................................................................18 5.3 Soil Sample Results .....................................................................................................19 5.4 Gamma Survey ............................................................................................................19 5.5 Survey Unit Evaluation - Sign Test ..............................................................................20 6 Quality Assurance/Quality Control (QA/QC) .......................................................................22 6.1 QA/QC .........................................................................................................................22 6.2 Preparation for Surveys................................................................................................22 6.3 Field Instruments..........................................................................................................22 6.4 Laboratory ....................................................................................................................23 7 References ........................................................................................................................24 TABLES Table 1 FSS Survey Units (in text)

Table 2 Summary of UNC Sample Analytical Results FIGURES Figure 1 UNC New Haven Site - 71 Shelton Avenue, New Haven, Connecticut Figure 2 UNC Buildings Sketch Figure 3 Building 3H and 6H Figure 4 Survey Units with Sample Points Figure 5 Gamma Walkover Survey ATTACHMENTS Attachment A SOP WGGM - 09 Procedure for Shallow Soil Sampling Attachment B Example of Visual Sample Plan Report arcadis.com ii

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation ACRONYMS AND ABBREVIATIONS AAA/IEM AAA Environmental Inc./Integrated Environmental Management, Inc.

ACM Asbestos Containing Material Arcadis Arcadis U.S., Inc.

cm2 centimeters squared cpm counts per minute DCGL or DCGLw Derived Concentration Guideline Level DOE Department of Energy dpm disintegrations per minute DQO Data Quality Objective FSS Final Status Survey GE General Electric Company GIS ESRI Geographic Information System GPS Global Positioning System GWS gamma walkover scan HEU Highly Enriched Uranium Ha alternative hypothesis H0 null hypothesis LBGR lower boundary of the gray region m meters m2 meters squared MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC minimum detectable concentration NRC Nuclear Regulatory Commission ORISE Oak Ridge Institute for Science and Education pCi/g picocuries per gram QA quality assurance QC Quality Control arcadis.com iii

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation RACR Remedial Action Completion Report ROC radionuclides of concern SNM Special Nuclear Material SU survey unit UNC United Nuclear Corporation VSP Visual Sample Plan WRS Wilcoxon Rank Sum arcadis.com iv

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 1 INTRODUCTION Arcadis U.S., Inc. (Arcadis) has prepared this Final Status Survey (FSS) Report on behalf of General Electric (GE) and the United Nuclear Corporation (UNC), for the former UNC Naval Products Division Facility, located at 71 Shelton Avenue in New Haven, Connecticut (Site), The purpose of this FSS Report was to collect the necessary data to demonstrate that the remaining conditions at the property, as a result of deconstruction and off-site disposal of above- and below-grade building debris and underlying soil, have been remediated to the level acceptable to the Nuclear Regulatory Commission (NRC).

1.1 Background

The H-tract facility, including building 6H/3H was constructed in 1915 as part of a larger complex used by the Winchester Corporation Olin Mathieson Chemical Corporation - Winchester Western Division for manufacturing firearms. In 1956, the mission of the H-tract was changed to the manufacture of nuclear fuel components and later into the fabrication of highly enriched reactor fuel components for the UNC Naval Products Division under the NRC Special Nuclear Materials (SNM) License SNM-368. The UNC Naval Products Division had primary control and jurisdiction over buildings 3H, 6H, 7H, 8H, 9H, 10H, 11H, 14H, and 44H in the H-Tract (UNC H-Tract).

Building 19H, 41H, and 50H were used by Gulf General Atomic and were already released for unrestricted use. Decontamination and decommissioning of the UNC H-tract was conducted between 1973 and 1976. The UNC H-Tract portion of the complex was removed from the license on April 22, 1976 and the assets transferred to the UNC Montville, Connecticut facility. The UNC H-tract, including buildings 3H and 6H (hereinafter the UNC site), was released for unrestricted use in accordance with Regulatory Guide 1.86 which contained the release criteria used at that time.

Between 1991 and 1997 NRC reviewed License releases dated back to the 1970s. Based on their review, the NRC concluded that an additional evaluation of the former UNC Site was warranted. As a result of their findings, in 1996 and 1997, Oak Ridge Institute for Science and Education (ORISE) conducted an assessment of the building and soils surrounding the Argyle Street sewer (ORISE,1997). The results of the sampling activities identified areas that contained enriched uranium that exceeded the 1981 NRC soil release criteria (30 picocuries per gram [pCi/g]

total uranium) (NRC,1983). In September 1997 GE acquired UNC, and in June 1998 agreed to undertake remediation (NRC, 2011). In 1998, UNC prepared and submitted a Site/Soil Characterization and Decommissioning Plan to NRC to remediate the areas identified during the sampling effort (UNC,1998). Additional subsurface characterization was performed by UNC in 2003 and a report documenting the sampling activities was submitted to the NRC June 7, 2005

((UNC, 2005).

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Based on the findings from the sampling activities, in 2005, UNC submitted a Decommissioning Plan (UNC, 2005) which detailed the facility decommissioning and decontamination activities for Building 3H, Building 6H, and an inactive connected sewer system. NRC returned the plan noting it appeared to contain no substantive changes to the 1998 Decommissioning Plan (NRC,2008).

In 2006, UNC submitted a Final Status Survey (FSS) Plan to assess whether the decontamination and decommissioning activities would be successful in meeting the release criteria approved in the Decommissioning Plan (AAA/IEM, 2006). The FSS was prepared in accordance with NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) [NRC, 2000].

Letters regarding the Derived Concentration Guideline Levels (DCGL) were also submitted in May and June 2008. For both, the NRC had no comments at that time but stated it would need to review the FSS Report before approving of a release of this site.(NRC 2008)

GE contractor, AAA/IEM, then prepared a Revised/Updated Cost Estimate and Work Plan for the Decommissioning Plan at the UNC Naval Products, Previously Licensed Facility which they submitted to GE on September 18, 2008.

A year later (December 2009) a new contractor Cabrera Services submitted a Draft Work Plan Site Decommissioning Former UNC Manufacturing Facility. The Plan was revised, and a Final Draft Work Plan Site Decommissioning Former UNC Manufacturing Facility submitted to GE March 2010.

In April 2011, NRC and UNC discussed the remediation and decommissioning of the former facility and the release of the property and surrounding area. In September 2011, UNC commenced remediation activities and by July 2012 completed most of the work described in the 2005 (1998) Decommissioning Plan. During the cleanup activities, UNC identified additional soil areas that exceeded 30 pCi/g of uranium. In July 2012, UNC submitted an addendum to the 2005 (1998) Decommissioning Plan (Cabrera, 2012) that used a dose-based release criterion (i.e., the Derived Concentration Guideline Level [DCGLw]). The revised DCGLw was calculated in 2008 (IEM, 2008) and submitted to NRC in 2012. The DCGLw was subsequently revised to meet the State of Connecticut's dose standard (19 millirems per year [mrem/year] versus 25 mrem/year) and approved by the NRC July 5, 2013 (Cabrera, 2013). The final DCGLw for soil was 435 pCi/g total uranium and the DCGLw for surfaces was based upon Regulatory Guide 1.86 Table 1 Acceptable Surface Contamination Levels.

Most of the areas that were evaluated and remediated after 2011 met the revised DCGLw for soils or the DCGLw for surface contamination. However, these areas were limited, did not reflect the entire site and, in part, were focused on surficial contamination (e.g. the South Trench).

Additionally, during the FSS of the South Trench (a concrete utility trench located along the south side of the building) soil samples were collected from drainage holes weep holes in the floor of the trench. Subsequent radiological investigations discovered that radioactive contamination had migrated through select drainage holes in the floor of the South Trench. A characterization survey (Cabrera, 2015), debris cleanup inside Building 3H/6H, and a supplemental radiological characterization survey (Cabrera, 2016) were performed to further characterize/remediate the arcadis.com 2

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation site. These investigations found that further work was required to remediate the contamination inside and beneath Building 3H/6H to allow release of the building.

Based on the history of property use, characterization studies and physical condition of the building, UNC, in conjunction with the Department of Energy (DOE), proposed to deconstruct the buildings and remove the debris, as well as a portion of the underlying soil (as needed). From September 2019 to October 2020, much the above- and below-grade portions of the building and underlying soils were removed and transported off-site for disposal. All above-ground building materials (i.e., walls, roof, electrical components, structural members, and windows) were deconstructed and shipped off-site for disposal at a regulated waste disposal facility or locally recycled. Most of the building floor slabs and sub-slab foundations (both perimeter and interior) have been removed. The South Trench and the eastern portion of the North Trench were deconstructed and shipped off-site for disposal. The central and western portions of the North Trench and the West and the Lateral trenches were backfilled with clean, reusable on-site debris and imported gravel. Additionally, rooms and equipment foundation under the building slab on grade floor were found and depending on sampling either removed or remain. All entrances and holes (e.g., utility chases) on the side of the trenches or in the east end of the facility were sealed with concrete blocks and mortar. An investigation of the stormwater drainage system was performed which included uncovering and collecting material of construction and soil/sediment contents from several brick and concrete masonry catch basins, roof drain basins and associated piping. Based on the analytical results from the characterization sampling, several of the basins were removed with those that remained backfilled with clean imported gravel. Last, gravel was imported to the site and used to grade the site nearly level with the existing ground surface at the building footprint perimeter.

Anticipating completion of site deconstruction and remediation, a Final Status Survey Plan was prepared and submitted to the NRC July 23, 2020 (UNC, 2020). The review of the Final Status Survey Plan was coordinated with CDEEP and based on their review the NRC had no further questions and expected activity to continue on the site (NRC, 2020) 1.2 Previous Investigations A number of remediation operations were completed by Cabrera from 2011 to 2012. These were detailed in the 2018 Remedial Action Completion Report and are briefly summarized below (Cabrera, 2018):

Decontamination of the Argyle Street sewer and soils. In 2011, UNC/GE engaged Cabrera to remove and replace the sewer line and associated bedding materials and soil.

Once the sewer excavation activities had been completed, Cabrera conducted a FSS.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Asbestos abatement and decontamination in South Trench, Lateral Trench and North Trench. Asbestos abatement in the South, Lateral and North trench was carried out by AIG, an asbestos abatement contractor. Asbestos pipe wrapping was often in the floor of the trench. A wet method was used on the pipes which were abrasively scrubbed to remove any rust. The trench floors were shoveled and vacuumed to remove as much asbestos, soil/sediment and debris as possible.

Characterization of soils under the South Trench weep holes, Lateral Trench and North Trench. Soils under weepholes were also investigated. Weepholes allowed water and residual contamination from the walls and floor to escape the utility tunnel and flow to the soils below the building. At one location the South Trench concrete was removed, and soil samples taken to 30 inches. It was determined that the soils under the South Trench exhibited contamination and a more detailed survey would be required.

Decontamination of Small Trench (floor of Building 3H). This small trench was 40 feet long one foot wide and 10 inches deep. After soil sampling, all soils from the trench were removed and disposed of.

Decontamination of Decon Pit soils and solid surfaces. The concrete floor above the Decon Pit was removed and soils excavated to a depth of 6 feet. The excavation was backfilled, and the concrete floor replaced. During the work, surface contamination was detected on portions of the floor and the walls. These were decontaminated and an FSS conducted.

Decontamination of X-Ray Read Room excavation soils and solid surfaces. The concrete floor was removed and excavation north and south of a structural concrete footer was initiated. South of the footer soil was excavated to a depth of six feet while on the north side soil was excavated to a depth of seven feet. In addition, a contaminated pipe chase was also located. To assure that structural integrity of the building was maintained these excavations were supported by soil borings to delineate the extent of contamination.

Ultimately the excavation was backfilled along with the pipe chase and the concrete floor restored.

Characterization and decontamination of Laydown and Haul Road area soils. During a baseline gamma walkover survey, Cabrera found an approximate 15 ft2 area of elevated gamma activity. Further characterization was conducted including down hole gamma, soil sampling and soil core scanning. Results lead to selected excavation in the Laydown Area and the Haul Road. Following excavation a FSS was conducted on both areas.

On-site gamma spectroscopy. Sample analysis using a Canberra In-Situ Object Counting System (ISOCS) high purity germanium detector to count soil/asphalt/concrete samples.

Packaging and transporting waste materials. All wastes were shipped using intermodal containers (IMCs) for safe off-site transportation and disposal.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Conduct and report on FSSs of decontaminated areas (FSS report).

Backfilling and Restoration of Decontaminated Areas. Restoration included, but was not limited to, replacing Argyle Street sewer, restoring Argyle Street asphalt and Shelton Avenue sidewalk and roadway, and replacing a garage and driveway on a neighboring property.

These activities are documented in the Remedial Action Completion Report (RACR) (Cabrera, 2018) which includes the FSSs conducted on the aforementioned areas. While the RACR has been submitted to the NRC, it has not been accepted as a Final Status Survey to allow release of the site or the Argyle Street sewer corridor. As a result, the Argyle Street Sewer remediation and survey activities have been included in this FSS.

1.3 2019 Cleanup Plan The 2018-2019 decision to deconstruct the building has resulted in much of the previous remediation and FSS activities having little relevance to the current final site conditions, with the exception of the Argyle Street Sewer FSS activities. For instance, the prior FSS focused on surface contamination in the building which was subsequently deconstructed. Activities performed during the 2019-2020 remediation included the following (UNC, 2019):

Asbestos Abatement of Category I nonfriable asbestos containing material (ACM) (i.e. built-up roofing systems, fire door insulation, glues and mastics, floor tile, paneling).

Asbestos Abatement of Category II friable ACM (i.e., window glazing, joint caulking, pipe, ceiling, and flange gasket insulation).

Removal of loose paint (known or assumed to contain elevated lead concentrations).

Removal of universal wastes (i.e., hydraulic fluids, oils, light bulbs, lamps, ballast, capacitors, biological hazards, batteries, and mercury and mercury-containing equipment).

Excavation and removal of soils under Buildings 3H and 6H, including Decon Pit, X-Ray Reading Room, Rectifier Room and Chemistry Laboratory.

Removal of below-grade pipes, sewer/drain lines and electrical conduits.

Removal of South Trench concrete and piping.

Removal of Buildings 3H and 6H concrete slab.

Removal of soils around the edges of vertical walls and under concrete slabs.

Removal of several catch basins, roof drain basins and associated suspect piping.

Partial removal of below building and equipment foundations.

Packaging and transporting waste material using IMCs for off-site transportation and disposal.

Characterization and FSS of site.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Backfilling and restoring Remediated Areas.

Thus, this FSS incorporates all areas of the UNC facility and combines discussions of previous remediation activities and survey results.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 2 DATA QUALITY OBJECTIVES Data Quality Objectives (DQOs) are qualitative and quantitative statements that establish a systematic procedure for defining the criteria by which data collection design is satisfied in order to make determinations regarding remediated properties. The DQOs at UNC include:

Clarifying the project problem.

Identifying the decision.

Defining the data necessary for achieving the end-use decisions.

Defining the study boundaries.

Determining the appropriate method of data collection.

Specifying the level of decision errors acceptable for establishing the quantity and quality of data needed to support the project decisions.

The overall quality assurance (QA) objective for this project is to develop and implement procedures for obtaining and evaluating data that meet the DQOs to confirm that the required remediation is accomplished. Specifically, radionuclide data will be generated to demonstrate that the site properties have achieved the remediation criteria to a specified degree of statistical certainty. QA procedures are established to see that field measurements, sampling methods and analytical data provide information that is comparable and representative of actual field conditions, and that the data generated are technically defensible.

2.1 State the Issue This FSS will be used to demonstrate that the residual radionuclide concentrations following remediation comply with concentration- and exposure-based criteria, per the decision documents.

The objective of FSS activities is to obtain data of sufficient quality to support an evaluation of the criteria for the property. Compliance will be satisfied based on guidance found in MARSSIM (NRC, 2000). Compliance will be demonstrated using surface gamma surveys, systematic soil samples and surface alpha surveys. Soil samples will include isotopic determination of U-234, U-235, and U-238, to determine total uranium.

2.2 Identify the Decision The overall objective is to determine if the radioactive contaminates exceed the DCGLw by more than the acceptable release criteria.

2.3 Inputs into the Decision Compliance was demonstrated using surface gamma surveys, systematic soil samples, surface wipes and direct alpha beta surface measurements. Gamma walkover surveys (GWS) covering 100% of the accessible area of the survey units were conducted to confirm there are no elevated arcadis.com 7

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation spots within the survey units. Residual area radioactivity levels of total uranium were determined by quantitative means (i.e., soil samples). Quantitative surveys provided representative data from each survey unit for comparison to the DCGLw. The results from laboratory analyses of volumetric samples and gamma counts from field surveys were used to drive decisions.

Statistical tests were used to determine whether specific survey units met release criteria for residual radioactivity. Uranium isotopes (i.e., U-234, U-235, U-238) are naturally occurring and are present in the environment. The background soil concentration, which was accepted by the NRC (AAA/IEM, 2005), was 3.43 pCi/g total uranium. The background concentration is a small fraction of the remedial criterion (DCGLw = 435 pCi/g total uranium) and did not adversely impact analysis results or conclusions.

MARSSIM recommends that nonparametric statistical tests, such as the Wilcoxon Rank Sum (WRS) test or the Sign test, be used to evaluate data. According to MARSSIM, the WRS test is recommended when the contaminant is present in the background, while the Sign test is used when the contaminant is not present in the background. Since the background uranium activity is less than 1% of the DCGLw, the impact of the background concentration was negligible. This results in the Sign test, rather than the WRS test, being used to demonstrate compliance with the remediation criteria.

2.3.1 Radionuclides of Concern License No. SNM-368 authorized the use of enriched uranium (greater than 97% uranium-235),

natural uranium, depleted uranium and thorium for research and nuclear fuel fabrication. Of these, thorium is dismissed as a radionuclides of concern (ROC) because the historical usage of thorium on-site was limited. Thus, highly enriched uranium (HEU) is the primary ROC for the site. HEU comprises uranium-234 (U-234), uranium-235 (U-235), and uranium-238 (U-238). HEU comprises a higher percentage of uranium-235 compared with natural uranium. When uranium is enriched to create HEU, the process separates uranium from its daughter products. Unlike natural uranium, HEU is not in secular equilibrium with its daughter products and monitoring for the daughter products is not necessary. However, the DCGLw refers to total uranium. Therefore, the ROC considered during the DCGLw determination for the FSS was total uranium i.e. the sum of U-234, U-235 and U-238.

2.3.2 Derived Concentration Guideline Level A DCGL is a derived radionuclide activity concentration that corresponds to a dose-based release criterion. The NRC initially established an original release criterion of 30 pCi/g total uranium for the site (SECY 81-0576). This criterion was used by Cabrera to evaluate residual radioactivity in the 2011-2012 decommissioning effort for certain portions of the site. After noting that residual radioactivity exceeding this criterion was potentially under the building, a new site-specific release criterion (DCGLw) based on a suburban resident scenario was requested. The doses were calculated using RESRAD and the results for 25 mrem/year were submitted to NRC. The final arcadis.com 8

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation DCGLw was reduced based upon the State of Connecticut dose limit of 19 mrem/year to a member of the public (AAA/IEM, 2008). The updated remedial concentration (DCGLw) for the site was established as 435 pCi/g total uranium (Cabrera, 2012), where the total uranium is the sum of the concentration of U-234, U-235 and U-238. As U-234 is an alpha emitter, when gamma spectroscopy was used to quantify the total uranium, the U-234 is estimated as 27 times the U-235 concentration (ORISE, 1997). Isotopic uranium concentrations were used to determine total uranium for the Sign test.

2.4 Define the Study Boundaries The area under consideration for the FSS was the entire property including the soils under the footprint of Buildings 3H and 6H, the soils under the South Trench, the surface soil of the property outside the building footprint, including the Laydown Area, Haul Route, and the former Buildings 7H, 8H, 9H, 10H, 11H, and 14H. Remaining concrete surfaces, footings, equipment foundations, roof drain basins and catch basins were scanned and sampled. The below-grade soils and ground surface along the Argyle Street sewer were evaluated against FSS DQOs based on the Cabrera work (Cabrera, 2018) 2.5 Data Collection Method The concentration of residual radioactivity and ROCs in the survey units was determined through the gamma walkover survey, volumetric sampling, and analysis of surface soils, and, if required, direct surface radioactivity measurements. Direct radiation measurements included gamma walkover surface scans of the survey units, static gross alpha scans, direct gamma surface measurements, and wipes.

2.5.1 Minimum Detectible Concentration All radiological measuring systems (probes and ratemeters/scalers) were selected based upon detection sensitivity to provide technically defensible results to meet the objectives of the survey.

The minimum detectable concentration (MDC) is an a-priori statement of instrument sensitivity and depends upon the background counting rate, detector efficiency and counting time.

Gamma scanning surveys were performed using a Ludlum 44-20 gamma probe, a 3 inch by 3 inch sodium iodide detector, coupled with a Ludlum 2221 ratemeter/scaler (or equivalent).

Alpha/beta surface scanning surveys were performed using a Ludlum 43-89 Alpha/Beta detector (or equivalent) with a 126 centimeters squared (cm2) active window coupled to a Ludlum 2360 analog meter with digital scaler.

For volumetric samples, the lower limit of detection was consistent with the detection level needed to evaluate environmental samples. Samples were analyzed by a vendor laboratory for U-234, U-235 and U-238 by alpha spectroscopy method DOE A-01-R and U-235 and U-238 (thorium-234) by gamma spectroscopy method DOE GA-01-R (EML300). When results from gamma spectroscopy method were used, the U-234 were estimated as 27 times the U-235. Per the vendor arcadis.com 9

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation laboratory, the lower limit of detection for uranium-isotopic determination is approximately 0.5 pCi/g.

2.6 Define Acceptable Limits on Decision Errors Appendix D in MARSSIM (NRC 2000) provides a discussion regarding decision errors. This discussion includes the concept that acceptable error rates must be balanced between the need to make appropriate decisions and the financial costs of achieving high degrees of certainty.

Errors can be made when making site remediation decisions. The use of statistical methods allows for controlling the probability of making decision errors.

When designing a statistical test, acceptable error rates for incorrectly determining that a site meets or does not meet the applicable decommissioning criteria must be specified. In determining these error rates, consideration should be given to the number of sample data points that are necessary to achieve them. Lower error rates require more measurements but result in statistical tests of greater power and higher levels of confidence in the decisions. In setting error rates, it is important to balance the consequences of making a decision error against the cost of achieving greater certainty.

The decisions necessary to determine compliance with the soil cleanup criteria are based on statistical hypotheses. These hypotheses will be tested using data from each survey unit. The state that is presumed to exist is expressed as the null hypothesis (H0). For a given null hypothesis, there is a specified alternative hypothesis (Ha) that is an expression of what is believed to be the state of reality if the null hypothesis is not true. The following discussion is based on MARSSIM (NRC, 2000).

2.6.1 Null and Alternative Hypotheses For the Sign test, the hypotheses selected for the FSS are as follows:

Null Hypothesis (H0):

The median concentration of the residual radioactivity in the survey unit is greater than the DCGLW.

versus:

Alternative Hypothesis (Ha):

The median concentration of the residual radioactivity in the survey unit is less than the DCGLW and meets the release criterion.

These hypotheses were chosen because the burden of proof is on the H0. The measured median concentration in the survey unit must be less than the DCGLw in order to pass.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Statistically based decisions will be utilized for evaluating whether the survey unit meets the release criteria. Statistical acceptability decisions, however, are always subject to error. Two possible error types are associated with such decisions.

The first type of decision error, called a Type I error, occurs when the H0 is rejected even though it is actually true. A Type I error is sometimes called a false positive. The probability of a Type I error is usually denoted by . This error could result in higher potential doses to future site occupants than prescribed by the dose-based criterion. For the UNC site, the maximum Type I error rate has been set at = 0.05.

The second type of decision error, called a Type II error, occurs when the H0 is not rejected even though it is actually false. A Type II error is sometimes called a false negative. The probability of a Type II error is usually denoted by . The power of a statistical test is defined as the probability of rejecting the H0 when it is false. It is numerically equal to 1-. Type II errors do not cause a higher dose to future occupants, but rather cause unnecessary remediation expenses, disposal costs and project delays. For UNC site, the Type II error rate has been set as =0.05.

2.6.2 Relative Shift The lower boundary of the gray region (LBGR), and the target values for and , are selected during the DQO process. For FSS planning purposes, the LBGR is set to one half the DCGLw.

The width of the gray region (DCGL - LBGR) is a parameter that is central to the Sign test. This parameter also is referred to as the shift (. The absolute size of the shift is actually of less importance than the relative shift /, where is an estimate of the standard deviation of the measured values in the survey unit. The relative shift, /, is an expression of the resolution of the measurements in terms of measurement uncertainty. The value of the relative shift is used to calculate the number of samples required to demonstrate that a survey unit has met the applicable release criteria (NRC, 2000).

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 3 SURVEY CRITERIA 3.1 Release Criteria The objective of FSS activities is to obtain data of sufficient quality and quantity to support an evaluation that the radiological conditions of properties following remediation meet the release criteria. In order to release a property, it must be adequately demonstrated that overall radiological residual concentrations in the soils and on surfaces do not exceed the dose based DCGLw criteria. The approved DCGLw for soil is 435 pCi/g total uranium.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 4 SURVEY UNITS All areas of a site will not have the same potential for residual contamination and will not need the same level of survey coverage to establish release criteria. All impacted soil areas can be subdivided into separate SUs based upon contamination potential and size. MARSSIM defines different classes for areas with different potential for contamination that require different degrees of survey effort. Section 2.2 of MARSSIM provides the following designations.

Non impacted areas: Areas that have no reasonable potential for residual contamination.

Class 1 Areas: Impacted areas that have, or had prior remediation, a potential for contamination (based upon site operating history) or known contamination above the DCGLw.

Class 2 Areas: Impacted areas that have, or had prior to remediation, a potential for contamination or known contamination, but are not expected to exceed the DCGLw.

Class 3 Areas: Impacted areas that are not expected to contain any residual radioactivity or are expected to contain levels of radioactivity that are a small fraction of the DCGLw.

MARSSIM recommends limiting survey unit sizes for soils as follows:

Class 1 - up to 2,000 meters squared (m2) for open areas and 100 m2 for structure.

Class 2 - 2,000 to 10,000 m2 for open areas and 100 to 1000 m2 for structures.

Class 3 - no limit for open areas or structures.

Survey units were originally assigned based upon the 2006 Final Status Survey Plan Table 1 (AAA/IEM, 2006). In the 2006 FSS Plan, the areas of the site subject to decommissioning were placed into three categories: subfloor soils; indoor residues; and sewer residues. The subsurface soils under the Decon Pit, Rectifier Room, X-Ray Reading Room, Chemistry Laboratory, Buildings 3H and 6H, and Argyle Street Sewer were classified as Class 1 areas. The soil outside of the Argyle Street sewer was classified as a Class 2 area. Fill soil from previous excavations were classified as a Class 3 area.

Soils under the Decon Pit, Rectifier Room, X-Ray Reading Room, Chemistry Laboratory and the Argyle Street sewer were remediated, with an FSS conducted on each and documented in the 2018 Remedial Action Completion Report (Cabrera, 2018). An FSS on the concrete in the South Trench was also conducted as a Structural FSS. However, as total removal of the building is completed, these areas, including the South Trench but excluding the Argyle Street sewer, are now incorporated as Class 1 survey units discussed in section 4.1.

Additional areas were classified based upon the Supplemental Characterization Survey (Cabrera, 2015). The site trench soils, onsite sewer and catch basins were classified as impacted areas and were all designated as Class 1 because of the similar potential for residual contamination.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 4.1 Class 1 Survey Units Based on previous remediation efforts and historical records, the following seven survey units were established: Former Site of Buildings 9H, 10H and 11H; Former Site of Buildings 7H, 8H and 14H; Former Site of Building 6H West Column 1 to 14; Former Site of Building 6H Center Column 14 to 33; Former site of Building 3H Column 33 to 48; The Laydown Area and Haul Road; and the South Trench and Southern Boundary. The size of the survey units presented in Figure 4 and Table 1 are estimates. The coordinates of each survey units vertices were taken from a surveyors map of the site which was used as the base map for the location of the sample points (see figure 4). The area was then calculated using the shoelace-polygon area algorithm in excel.

As defined in the Cleanup Plan, the impacted soils in each survey unit within the building footprint were excavated and transported off-site for disposal. The FSS for the subsurface areas included soil scanning and sampling.

The Argyle Street Sewer was included for completeness and is further discussed in section 4.4 Table 1 FSS Survey Units Area Approximate Survey Unit Classification Description Designation Size (meter2)1 Area 1 Surface soils within and Former Site of around former Building 9H Buildings 9H, 10H, Class 1 1,354 offices, 10H Hot Waste 11H Processing and 11H Metallurgy Laboratory Area 2 Former Site of Surface soils within and Buildings 7H, 8H, Class 1 1,939 around former Buildings 7H, and 14H 8H and 14H Area 3 Former Site of Subsurface soils under Building 6H West Building 6H includes Class 1 1,632 Chemistry Laboratory and Column 1 to 14 North Trench areas Area 4 Former Site of Subsurface soils under Building 6H Center Class 1 2,090 Building 6H includes Lateral Column 14 to 33 and North Trench areas Area 5 Subsurface soils under Former Site of Building 3H includes Decon Building 3H Class 1 1,785 Pit, Rectifier Room, X-Ray Column 33 to 48 Reading Room areas Area 6 Laydown Area and Surface soils north and east Class 1 2,173 Haul Road of Building 3H arcadis.com 14

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Area Approximate Survey Unit Classification Description Designation Size (meter2)1 Area 7 Soils underneath the former South Trench and includes Former Site of weep holes from Building South Trench and 3H, Building 6H, and Class 1 552 Southern Chemistry Laboratory and Boundary property between the South Trench and southern property line Argyle Street Subsurface soils adjacent to Class 1 1,108 Sewer former Argyle Street sewer Note 1 - Estimated using a surveyors map and the shoelace polygon area algorithm 4.2 Class 2 Survey Unit There were no Class 2 survey units on this site.

4.3 Class 3 Survey Unit There were no Class 3 survey units on this site.

4.4 Argyle Street Sewer Inspection activities conducted by NRC in 1997 revealed that residual HEU existed inside of the inactive sewer that traversed the adjacent property line along Argyle Street (ORISE, 1997). In response, in 2011, UNC/GE engaged Cabrera to remove and replace the sewer line and associated bedding materials and soil. Once the sewer excavation activities had been completed, Cabrera conducted a FSS which included a 100% gamma walkover survey, the collection of 22 systematic surface soil samples, and the collection of 42 biased soil samples. Composite volumetric samples were collected from overburden material (0 - 10 feet depth) along the sewer.

The sand and soil material surrounding the sewer line, the sludge from inside the sewer, and the sewer pipe were also sampled for waste profiling and disposal purposes. These results were presented in the Remedial Action Completion Report (RACR) (Cabrera, 2018). Cabrera used the Sign test to evaluate the excavation spoil results and determined that they were substantially less than the DCGLw and therefore met the FSS release criteria. As a result, the spoil materials were subsequently used as clean fill material. The maximum concentration in the systematic sample set had a total uranium activity of 1.1 pC/gm while that in the biased sample set was 9.7 pCi/g.

The surface scans were indistinguishable from background radiation.

After the FSS activities were completed, the sewer line trench was backfilled with clean imported fill material.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 4.5 Background Radioactivity Uranium isotopes (i.e., U-234, U-235 and U-238) are naturally occurring and are present in the environment. The background soil concentration was previously determined as 3.43 +/-1.2 pCi/g and accepted by the NRC in 1999 (AAA/IEM, 2005).

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 5 SAMPLING After site remediation activities were completed, gamma walkover surveys, volumetric sampling and analysis of surface soils and required direct surface radioactivity measurements, were employed to assess the quantity of residual radioactivity present at the site. The FSS data for the ROC will be compared with the release criteria presented in Section 3.1. Specifically, the DCGLw limit for uranium in the soil is 435 pCi/gram and total uranium on surfaces is less than 5,000 disintegrations per minute (dpm) /100 cm2, 1,000 dpm /100 cm2 for removable contamination, and a maximum of 15,000 dpm /100 cm2.

5.1 Number of Sample Locations The Sign statistical test was used to determine whether the site is suitably free of residual radioactivity. The minimum number of systematic sample points required for each unit can be determined using MARSSIM Section 5.5 for guidance (NRC, 2000).

MARSSIM provides methods to determine the minimum number of measurement locations (N) required for each survey unit or reference area for selected values of (Type I error), (Type II error), and / (relative shift). The minimum number were calculated using the equation below (equation 5-2 in MARSSIM), with an increase of 20% to account for uncertainties in the calculation and to obtain sufficient data points to attain the desired power level for the statistical tests while also allowing for possible lost or unusable data.

Equation 2, which is used to calculate N (see Section 5.5 of MARSSIM), relies on Sign P -- the probability that a random measurement from the survey unit exceeds a random measurement from the background reference area by less than the DCGLw when the survey unit median is equal to the LBGR above background.

( )

Equation 2 =

( . )

For UNC, the following values were used:

The DCGLw for the remaining site soils is 435 pCi/g total uranium.

The lower bound of the gray region (LBGR) is the statistical region where the consequences of decision errors are relativity minor and is generally accepted to be equal to one-half of the DCGLw. Thus, the LBGR is 50% of the DCGLw or 217.5 pCi/g.

The shift () is equal to the width of the gray region (DCGL - LBGR) or 435 - 217.5 = 217.5 pCi/g A standard deviation () of 20 pCi/g (approximately the square root of the DCGLw or one standard deviation) is assumed.

The relative shift is defined as /. 217.5 ÷ 20 = 10.8.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Per MARSSIM Table 5.4 provides a Sign P of 1.

The standard decision error levels is the acceptable probability of incorrectly concluding the site median is less than the threshold, (0.05) and is the acceptable probability of incorrectly concluding the site median exceeds the threshold, (0.05) leads to decision error percentile of 1.645 for both from Table 5.2 (Z and Z )

(1.645 + 1.645) 10.82 =

4(1 0.5)

Results in a total of 10.82 sample points. An additional 20% (+2.16) will be added to account for sampling uncertainties, for a total of 13.96, rounded up to 14 samples.

According to MARSSIM, the MDC of the scanning unit must be below the DCGLw so that potential elevated areas are detected. The MDC for the Ludlum 44-10 sodium iodine probe is 136 pCi/gram, which is less than the required site DCGLw for a survey unit. Therefore, 14 sample locations are sufficiently sensitive to detect an area of elevated concentration and no additional systematic sample locations are required. Thus, the minimum number of systematic samples is 14 for each Class 1 survey unit.

5.2 Soil Sample Collection As noted in MARSSIM Appendix D, a triangular grid is generally more effective in locating small areas of elevated activity. The data points are then positioned throughout the survey unit from a randomly selected starting point and the established sampling pattern. Grids are presumed in a single flat plane. Pacific Northwest National Laboratory Visual Sampling Plan Version 7.12a was used to determine the location of the sample points (PNL, 2020). The minimum number of locations for each Class 1 SU was 14. The number of systematic samples in a SU may be increased due to grid edge effects.

Soil samples were collected between October 1 and October 5, 2020. Initially the soil sample locations were surveyed in and staked or pinned. Where necessary a few of the locations were moved as they were on a tree or on concrete. There were also some in the South Trench Southern Boundary SU that were considered hazardous as the soil was at the edge of a trench which remained after the South Trench concrete was removed. Less than ten samples locations were moved a few feet. These were resurveyed and staked/pinned. Figure 4 presents the final location of the sample locations.

For concrete features (e.g. equipment foundation) left on site, discrete soil samples were not taken. Systematic sample points located on concrete were obtained from soil located as close as possible to the sample point. If sufficient soil was on the concrete such as a sub-slab foundation, a sample was taken. Otherwise remaining concrete surfaces were alpha/beta scanned and tested for removable and fixed contamination.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Prior to taking a soil sample, a one-minute gamma count of the location of the sample was taken with a sodium iodine probe coupled to a ratemeter (e.g. Ludlum 44-10 2 x 2 sodium iodine probe coupled to a Ludlum 2221 ratemeter scaler, or equivalent). The count rate varied between 5,789 counts per minute (cpm) and 14,533 cpm with an average of 8,125 +/- 2,938 cpm. The site background is about 8,000 cpm.

Volumetric discrete soil samples were taken in accordance with approved sampling procedure (see Attachment A). Generally, a single soil sample was obtained from the surface at each sample location to a depth of two to three inches. The sample consisted of the collection of 400 to 500 grams of soil, which were homogenized and shipped to Pace National Analytical Laboratory located in Mt. Juliet, TN (Pace).

Volumetric samples were analyzed for U-234, U-235 and U-238 by alpha spectroscopy method DOE A-01-R and U-235 and U-238 (Th-234) by gamma spectroscopy method DOE GA-01-R.

Gamma spectroscopy U-234 can be estimated by multiplying the U-235 result by 27, as was previously done by ORISE to estimate the U-234 activity concentration.

Nineteen (19) fixed and removable contamination samples from residual surface concrete were collected in accordance with approved sampling procedures. In general, the surface was brushed to remove any loose debris and dirt. The face of an alpha/beta probe was placed over the sample location and the total counts (alpha and beta) recorded for one (1) minute. Subsequently, swipe samples, using dry glass fiber filters (47 mm Whatman filters, or equivalent), was taken over the designated surface area. The swipes were shipped to Co-Physics Corporation located in Florida, NY (Co-Physics) for analysis using USEPA Method 900.0. The results indicated no fixed or removable contamination.

5.3 Soil Sample Results One hundred and three (103) soil samples were collected and sent to Pace for uranium isotopic determination by both alpha spectroscopy and gamma spectroscopy. Results are presented in Table 2. The maximum total uranium was UNC-54 at 23.76 pCi/g. The next greatest was sample UNC-100 with total uranium of 8.15 pCi/g, followed by UNC-102 at 8.03 pCi/g, UNC-101 at 6.16 pCi/g and UNC-73 at 5.53 pCi/g. Beyond these results, there were seven sample results greater than background, 3.43 pCi/g. The remaining ninety-one sample results were 1 to 2 pCi/g total uranium which is slightly less than typical (natural) soil concentration of 2.5 pCi/g.

5.4 Gamma Survey MARSSIM suggests that gamma scan surveys for Class 1 SUs be performed to cover 100 percent of the accessible areas in each SU. Class 2 and Class 3 SU scans can be performed over smaller portions of the accessible areas. The purpose of the gamma survey is to identify the potential presence of smaller, discrete area of residual radioactivity.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation GWSs were performed to cover 100 percent of all accessible areas in each Class 1 SU. Due to vegetation and surface instability, the strip (about 3 to 4 feet) between the southern fence line and the South Trench was not scanned.

The GWS was conducted using a gamma scan system consisting of a 3 inch x 3 inch sodium iodine scintillator (gamma probe Ludlum 44-20) coupled to a ratemeter/scaler. The probe was held three to six inches above the ground with the surveyor walking at a rate no faster than 3 feet per second. Transects were 3 feet apart assuring sufficient coverage of all areas. The probe was suspended from a rope allowing it to swing through a small arc thus covering more area and resulting in a serpentine pattern. The gamma scan system was connected to a global positioning system (GPS [R2 GNSS Receiver GPS system with Terrasync software]) and a 10-color screen pen-based computer. The instruments were Bluetooth-linked creating an electronic file that recorded the coordinates along with the surface exposure rate readings as transects were traversed. This file was linked with ESRI Geographic Information System (GIS) software to create a spatial representation of the count rate data.

The GWS was conducted between September 17, 2020 and October 6, 2020 as portions of the site became accessible. The soil background was determined to be about 22,000 cpm from various off-site soil locations. Over 32,000 points were collected with the maximum count rate of 63,180 cpm and average count rate of about 18,000 cpm. The maximum count rate was less than three times background indicating no area with elevated gamma counts.

Figure 5 presents the results of the GWS. As indicated, gamma count rates were color coded with green for count rate less than background (22,000 cpm for the 3x3 inch NaI gamma probe), blue for count rates between background and twice background and orange for count rates greater than twice background but less than three times background. There were no counts above three times background. As indicated in the figure, most of the site was at or below background (the green area). Some of the site was between background and twice background (blue). There were a few very small areas along the south trench which had count rates greater than twice background. Whether these were due to coal ash or site residue material cannot be determined.

In summary, the GWS showed no elevated areas which would require biased sampling and additional investigation.

5.5 Survey Unit Evaluation - Sign Test Because the background natural concentration of uranium is less than 1% of the sites DCGLw, all survey units were evaluated using the Sign test (MARSSIM section 8.3.2). The Sign tests H0 states the median concentration of residual radioactivity on the survey unit will be greater than the DCGLw. This is assumed to be true unless the statistical test indicates that it should be rejected. If the null hypothesis is rejected, the survey unit passes the FSS and can be released for unrestricted use. The Sign test is applied as outlined in the following steps from MARSSIM.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation Assume the set of results from the sample analysis for total uranium is {Xi} where i = 1 to 14. This set will be evaluated as follows:

1. List the set of measurements.

2. Subtract each measurement Xi, from the DCGLw to obtain the differences: Di = DCGLw - Xi, i =1 to14

3. Discard each difference that is exactly zero and reduce the sample size by the number of such zero measurements.

4. Count the number of positive differences. The result is the test statistic S+. Note that a positive difference corresponds to a measurement below the DCGLw and contribute evidence that the survey unit meets the release criterion.

5. The value of S+ is compared to the critical value. For 14 samples, the critical value is 10 (MARSSIM Appendix I Table I.3, =0.05). If S+ is greater than the critical value (10 for this case), the null hypothesis is rejected.

If the Sign tests null hypothesis is rejected, then it has been adequately demonstrated that overall radiological residual concentrations in the soil do not exceed the dose based DCGLw criteria.

Table 2 presents the results of the soil sample analysis. As indicated in the table and previously discussed (section 5.3) none of the soil samples had total uranium greater than the DCGLw. The maximum total uranium concentration was 23.71 pCi/g a factor of eighteen less than the DCGLw.

Based on the results, the application of the sign test to each SU was straightforward. The sign test requires each measurement in an SU be subtracted from the DCGLw. By inspection, none of the SUs had a sample which gave a positive difference, therefore the test statistic S+ for each SU was 14. As each S+ (14) was greater than the critical value 10, the null hypothesis was rejected for each SU. As noted above if the Sign tests null hypothesis is rejected for an SU, then it has been adequately demonstrated that overall radiological residual concentrations in the soil for that SU does not exceed the dose based DCGLw criteria. As this is the case for each SU then each SU passed the FSS and the entire site can be released for unrestricted use.

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 6 QUALITY ASSURANCE/QUALITY CONTROL (QA/QC) 6.1 QA/QC Activities associated with this FSS were performed in accordance with written procedures and approved protocols in order to achieve consistent, repeatable results. The site RSO reviewed the survey results to confirm no areas exhibited elevated radiation levels. This review verified that the data were recorded in a consistent manner and were suitable for inclusion in the FSS Report.

6.2 Preparation for Surveys GWS transects and systematic sample points were identified prior to sampling to facilitate reproducibility of sample results. The computer code, Visual Sample Plan (VSP), was used to select systematic sample locations within each SU. The sample locations were surveyed and flagged (staked or pinned) to assist sampling and confirmatory surveys (PNL, 2020).

The survey activities for each SU began with a GWS, conducted over the entire site. The surface scans were reviewed and indicated that no measurements appear to exceed the investigation criteria. Next, the VSP-identified systematic soil samples and surface direct gamma measurements were taken. No biased soil samples were taken as the GWS did not identify any areas with elevated gamma count rates.

6.3 Field Instruments Instruments and equipment used met the required minimum detectible concentration. Instruments were operated in accordance with either written procedures or manufacturers manuals. Current calibration was be kept onsite for review and inspection during the survey. The records included, at minimum:

Equipment name, model, and serial number Manufacturer Date of calibration Calibration due date Instruments were maintained and calibrated to the manufacturers specifications to foster traceability, sensitivity, accuracy and precision.

Prior to and after daily use, instruments were QC checked by comparing the instrument response to a designated gamma source and background radiation. This was essentially a drift test to assure the instrument response was not drifting due to factors such as low battery voltage, light leaks, declining photomultiplier tube, or the like. QC source checks consisted of one-minute integrated counts with the designated source positioned in a reproducible geometry, performed at the designated location. Background checks were performed in an identical fashion, but with arcadis.com 22

FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation the source removed. The results of the background and QC checks were recorded in a field logbook. Prior to the start of initial surveys, this procedure was repeated at least ten times to establish average instrument response.

Instrument response to the designated QC check source were evaluated against the average established at the start of the field activities. A performance criterion of +/- 2 sigma of the average was established as an investigation action level. A performance criterion of +/-3 sigma of this average was established as a failure level requiring corrective action. Results exceeding this criterion would be investigated and appropriate corrections to instrument readings made. If the response is affected by factors beyond personnel control, such as large humidity or temperature change, the instrument(s) in question would be removed from service while investigations and corrective actions initiated. None of the instruments failed the drift test.

Instrument response to background was used to establish a mean background response for each instrument, to monitor gross fluctuations in background activity, and to evaluate detector response.

During QC checks, instruments used to obtain radiological data were inspected for physical damage, current calibration and erroneous readings in accordance with applicable protocols.

Instrumentation that did not meet the specified requirements of calibration, inspection or response check were removed from operation. If the instrument fails the QC response check, any data obtained to that point, but after the last successful QC check, will be considered invalid due to faulty instrumentation. None of the instruments were removed from operation.

6.4 Laboratory All laboratory analyses were performed by Pace National Analytical Laboratory, a National Environmental Accreditation Program, or NELAP, certified laboratory (NELAP Accreditation number Al 30792).

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation 7 REFERENCES AAA/IEM, 2005. Integrated Environmental Management, Inc. Radiological Characterization of the Former UNC Manufacturing Facility, New Haven Connecticut AAA Environmental, Inc./Integrated Environmental Management, Inc. May 31, 2005.

AAA/IEM, 2006. Final Status Survey Plan for the Former UNC Manufacturing Facility, New Haven, Connecticut. AAA Environmental, Inc./Integrated Environmental Management, Inc.

September 6, 2006.

AAA/IEM, 2008. Integrated Environmental Management, Inc. Derived Concentration Guideline Levels for Decommissioning the former UNC Manufacturing Facility, New Haven, Connecticut. AAA Environmental, Inc./Integrated Environmental Management, Inc. June 16, 2008.

Cabrera, 2012. Cabrera Services, Inc. Decommissioning Plan Addendum. Site Decommissioning Former UNC Manufacturing Facility, New Haven, Connecticut. July 2012.

Cabrera, 2013. Cabrera Services, Inc. Final site Characterization Plan Site Decommissioning Former UNC Manufacturing Facility, New Haven, Connecticut. July 2013.

Cabrera, 2015. Characterization Survey Report. Site Decommissioning Former UNC Manufacturing Facility, New Haven, Connecticut. Cabrera Services Inc. April 2015.

Cabrera, 2016. Supplemental Radiological Survey Plan - Buildings 3H/6H (Floor Surfaces) and Former Buildings 9H/10H/11H (Subsurface Soils). Former UNC Manufacturing Facility, New Haven, Connecticut. March 2016.

Cabrera, 2018. Remedial Action Completion Report Site Decommissioning Former UNC Manufacturing Facility. November 2018 NRC, 1983. FC 83-23, Fuel Cycle Policy and Guidance Directive Guidelines for Decontamination of Facilities and Equipment Prior Release for Unrestricted Use or Termination of Licenses for Byproduct or source Materials, April 1983.

NRC,1998. United States Nuclear Regulatory Commission, A Nonparametric Statistical Methodology for the Design and Analysis of Final Status Decommissioning Surveys, NUREG-1505, Rev 1.

NRC, 2000. United States Nuclear Regulatory Commission, Multi-Agency Radiation Survey and Site Investigation Manual MARSSIM, NUREG-1575, Rev 1.

NRC, 2004. NUREG-1576, Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP).

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FINAL STATUS SURVEY REPORT: Former United Nuclear Corporation NRC, 2008,.Letter R.K Lorson NRC to R. Bonito UNC Naval Products; Status of NRCs Review pf UNC-New Haven, Connecticut Decommissioning Plan, Final Status Survey Plan and Derived Guideline Levels for Decommissioning, Accession Number ML081890407, July 7, 2008.

NRC, 2011. Letter Judith A. Joustra NRC to John Uruskyj Remedial Project Manager GE, NRC Site Visit Report No. 07000371/2011001, General Electric Corporation Environmental Programs, Former United Nuclear Corporation Naval products Facility, New Haven Connecticut, Accession Number ML111370419, May 13, 2011.

NRC, 2020. Letter Anthony Dimitiradis to James W. Van Nortwick Technical Environment Engineering Expert, Global Operations, Environment, Heath, and Safety, General Electric, Status of NRCs Review of the Final Status Survey Plan, Revision 2, for the Former United Nuclear Corporation Naval Products Site in New Haven, Connecticut. (August 26, 2020)

ORISE, 1997. Oak Ridge Institute for Science and Education (ORISE), 1997. ORISE.

Radiological Scoping Survey of Buildings 3H and 6H at the Former UNC H-Tract Facility, New Haven, Connecticut. January.

PNL, 2020. Visual Sampling Plan A Tool for Design and Analysis of Environmental Sampling Version 7.12a Pacific Northwest National Laboratory.

SECY-81-0576, 1981. Disposal or Onsite Storage of Residual Thorium or Uranium (Either as Natural Ores or Without Daughters Present) from Past Operation. October 1981.

UNC, 1998. UNCs Site /Soil Characterization and Decommissioning Plans, August 1998.

UNC, 2005. Decommissioning Plan UNC Naval Products Previously Licensed Facility in New Haven, CT, Revision 1, June 7, 2005.

UNC, 2019. Cleanup Plan Former United Nuclear Corporation Naval Products Facility, New Haven Connecticut. May 2019.

UNC, 2020. Final Status Survey Plan Revision 2 Former United Nuclear Corporation Naval Products Facility, New Haven Connecticut. July 23, 2020.

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TABLE Table 2 Summary of UNC Sample Analytical Results SDG # L1271685 L1271685 L1271685 L1271685 L1271685 Location ID: UNC-1 UNC-2 UNC-3 UNC-4 UNC-5 Date Collected: 10/03/20 10/03/20 10/03/20 10/03/20 10/03/20 Sample Name: Units UNC-1 10032020 UNC-2 10032020 UNC-3 10032020 UNC-4 10032020 UNC-5 10032020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.796 +/-0.263 0.495 +/-0.266 0.254 +/-0.329 0.554 +/-0.313 0.644 +/-0.314 Uranium-235 pCi/g 0.0856 +/-0.123 0.0462 +/-0.0950 0.0368 +/-0.128 -0.009360000 +/-0.102 0.0159 +/-0.108 Uranium-238 pCi/g 0.588 +/-0.220 0.458 +/-0.212 0.323 +/-0.231 0.682 +/-0.264 0.520 +/-0.252 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.796 J +/-1.04 0.232 U +/-0.764 0.388 U +/-0.516 0.0834 U +/-0.775 -0.0491000 U +/-1.03 Uranium-235 pCi/g 0.108 +/-0.0617 0.0320 U +/-0.0403 0.0758 U +/-0.0535 0.0673 U +/-0.0393 0.0618 J +/-0.0686 SDG # L1271685 L1271685 L1271685 L1271685 L1271685 Location ID: UNC-6 UNC-7 UNC-8 UNC-9 UNC-10 Date Collected: 10/03/20 10/03/20 10/03/20 10/03/20 10/03/20 Sample Name: Units UNC-6 10032020 UNC-7 10032020 UNC-8 10032020 UNC-9 10032020 UNC-10 10032020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.508 +/-0.230 0.533 +/-0.221 0.725 +/-0.284 0.746 +/-0.302 0.0669 +/-0.270 Uranium-235 pCi/g 0.0687 +/-0.0937 0.0949 +/-0.0953 0.0264 +/-0.0693 0.0438 +/-0.113 -0.009620000 +/-0.104 Uranium-238 pCi/g 0.410 +/-0.220 0.395 +/-0.194 0.654 +/-0.216 1.08 +/-0.289 0.502 +/-0.227 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g -0.45400 U +/-1.20 0.335 U +/-0.723 0.107 U +/-0.748 0.200 U +/-0.764 0.762 J +/-0.922 Uranium-235 pCi/g 0.0635 U +/-0.140 0.0866 U +/-0.0401 0.182 U +/-0.0962 0.0914 U +/-0.0421 0.0458 J +/-0.0553 SDG # L1271685 L1271685 L1271685 L1271685 L1271685 Location ID: UNC-11 UNC-12 UNC-13 UNC-14 UNC-15 Date Collected: 10/05/20 10/03/20 10/03/20 10/03/20 10/05/20 Sample Name: Units UNC-11 10052020 UNC-12 10032020 UNC-13 10032020 UNC-14 10032020 UNC-15 10052020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.339 +/-0.200 0.108 +/-0.302 1.28 +/-0.281 0.807 +/-0.292 0.239 +/-0.164 Uranium-235 pCi/g -0.0256000 +/-0.0576 0.0770 +/-0.104 0.0984 +/-0.109 -0.008330000 +/-0.114 0.00795 +/-0.0748 Uranium-238 pCi/g 0.560 +/-0.208 0.216 +/-0.198 0.723 +/-0.215 0.954 +/-0.264 0.410 +/-0.177 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.0705 U +/-0.658 -0.12000 U +/-1.06 0.103 U +/-0.629 0.498 U +/-0.713 0.133 U +/-0.785 Uranium-235 pCi/g 0.110 U +/-0.0821 0.0536 J +/-0.0648 0.0318 U +/-0.0341 0.0485 U +/-0.0919 0.0634 U +/-0.0423 SDG # L1271685 L1271685 L1271685 L1271685 L1271685 Location ID: UNC-16 UNC-17 UNC-18 UNC-19 UNC-20 Date Collected: 10/03/20 10/03/20 10/03/20 10/03/20 10/03/20 Sample Name: Units UNC-16 10032020 UNC-17 10032020 UNC-18 10032020 UNC-19 10032020 UNC-20 10032020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.03 +/-0.364 0.414 +/-0.305 1.89 +/-0.760 1.89 +/-0.760 0.736 +/-0.306 Uranium-235 pCi/g -0.0866000 +/-0.113-0.009470000 +/-0.0605-0.0536000 +/-0.153 -0.0536000 +/-0.153 0.0799 +/-0.186 Uranium-238 pCi/g 0.695 +/-0.323 0.545 +/-0.260 0 +/-0.353 0 +/-0.353 1.00 +/-0.330 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.279 U +/-0.758 0.326 U +/-0.925 0.180 U +/-0.748 -0.0346000 U +/-0.729 1.17 J +/-0.918 Uranium-235 pCi/g 0.172 U +/-0.0939 0.0804 +/-0.0619 0.191 U +/-0.0502 0.366 U +/-0.117 0.0905 U +/-0.0446 FSS Sample Results.xlsx Page 1 of 6 12/10/2020

Table 2 Summary of UNC Sample Analytical Results SDG # L1271685 L1271685 L1271685 L1271685 L1271685 Location ID: UNC-21 UNC-22 UNC-23 UNC-24 UNC-25 Date Collected: 10/03/20 10/03/20 10/03/20 10/03/20 10/03/20 Sample Name: Units UNC-21 10032020 UNC-22 10032020 UNC-23 10032020 UNC-24 10032020 UNC-25 10032020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.710 +/-0.303 0.434 +/-0.322 0.574 +/-0.334 0.663 +/-0.265 0.870 +/-0.293 Uranium-235 pCi/g 0.0671 +/-0.106 -0.0303000 +/-0.0906-0.009730000 +/-0.110 0.0476 +/-0.0983 0.115 +/-0.115 Uranium-238 pCi/g 0.518 +/-0.229 0.145 +/-0.177 0.459 +/-0.238 0.606 +/-0.229 0.684 +/-0.272 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.419 U +/-1.07 0.281 U +/-0.649 0.612 U +/-0.677 -0.41300 U +/-0.667 0.795 J +/-1.20 Uranium-235 pCi/g 0.0932 +/-0.0669 0.121 U +/-0.0857 0.0722 U +/-0.0348 0.0467 U +/-0.0828 0.0813 J +/-0.0690 SDG # L1271685 L1271685 L1271685 L1271685 L1271693 Location ID: UNC-26 UNC-27 UNC-28 UNC-29 UNC-30 Date Collected: 10/03/20 10/03/20 10/03/20 10/03/20 10/01/20 Sample Name: Units UNC-26 10032020 UNC-27 10032020 UNC-28 10032020 UNC-29 10032020 UNC-30 10012020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.618 +/-0.242 0.401 +/-0.266 0.439 +/-0.269 0.618 +/-0.309 0.597 +/-0.275 Uranium-235 pCi/g 0.0267 +/-0.0713 0.0307 +/-0.0785 -0.009390000 +/-0.0973 0.0524 +/-0.113 -0.009670000 +/-0.119 Uranium-238 pCi/g 0.345 +/-0.192 0.501 +/-0.204 0.386 +/-0.195 0.819 +/-0.255 0.655 +/-0.227 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.402 U +/-0.617 0.589 U +/-0.640 0.680 J +/-1.09 0.350 U +/-0.755 1.21 +/-0.997 Uranium-235 pCi/g 0.0327 U +/-0.0337 0.0489 U +/-0.0780 0.0416 J +/-0.0684 0.113 U +/-0.0425 0.0455 J +/-0.0725 SDG # L1271693 L1271693 L1271693 L1271693 L1271693 Location ID: UNC-31 UNC-32 UNC-33 UNC-34 UNC-35 Date Collected: 10/01/20 10/01/20 10/01/20 10/01/20 10/01/20 Sample Name: Units UNC-31 10012020 UNC-32 10012020 UNC-33 10012020 UNC-34 10012020 UNC-35 10012020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.843 +/-0.288 0.871 +/-0.323 0.518 +/-0.352 0.747 +/-0.316 0.627 +/-0.300 Uranium-235 pCi/g 0.176 +/-0.145 0.250 +/-0.201 0.114 +/-0.128 0.100 +/-0.114 0.0667 +/-0.105 Uranium-238 pCi/g 0.864 +/-0.273 0.683 +/-0.303 0.592 +/-0.290 0.857 +/-0.276 0.779 +/-0.281 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.635 J +/-0.829 0.318 U +/-0.776 0.621 U +/-0.652 0.257 U +/-0.669 0.727 U +/-1.01 Uranium-235 pCi/g 0.0891 +/-0.0576 0.0498 J +/-0.0540 0.113 U +/-0.0646 -0.11700 U +/-0.283 0.148 U +/-0.115 SDG # L1271693 L1271693 L1271693 L1271693 L1271693 Location ID: UNC-36 UNC-37 UNC-38 UNC-39 UNC-40 Date Collected: 10/01/20 10/01/20 10/01/20 10/01/20 10/01/20 Sample Name: Units UNC-36 10012020 UNC-37 10012020 UNC-38 10012020 UNC-39 10012020 UNC-40 10012020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.60 +/-0.356 1.03 +/-0.361 0.820 +/-0.362 2.31 +/-0.503 0.382 +/-0.218 Uranium-235 pCi/g 0.0960 +/-0.154 -0.0340000 +/-0.0836-0.008660000 +/-0.100 0.0832 +/-0.111 0.00824 +/-0.0861 Uranium-238 pCi/g 1.46 +/-0.335 0.985 +/-0.313 0.794 +/-0.305 2.03 +/-0.465 0.449 +/-0.214 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.179 U +/-0.950 1.33 J +/-2.13 0.226 U +/-1.24 2.65 J +/-1.78 0.338 U +/-0.475 Uranium-235 pCi/g 0.125 U +/-0.0487 0.121 J +/-0.146 0.112 +/-0.0767 0.625 U +/-0.207 0.0806 U +/-0.0487 FSS Sample Results.xlsx Page 2 of 6 12/10/2020

Table 2 Summary of UNC Sample Analytical Results SDG # L1271693 L1271693 L1271693 L1271693 L1271693 Location ID: UNC-41 UNC-42 UNC-43 UNC-44 UNC-45 Date Collected: 10/01/20 10/01/20 10/01/20 10/01/20 10/01/20 Sample Name: Units UNC-41 10012020 UNC-42 10012020 UNC-43 10012020 UNC-44 10012020 UNC-45 10012020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.977 +/-0.298 1.24 +/-0.360 2.44 +/-0.477 1.08 +/-0.295 0.351 +/-0.271 Uranium-235 pCi/g -0.0767000 +/-0.106 0.0593 +/-0.101 0.0883 +/-0.101 0.111 +/-0.121 -0.0261000 +/-0.0769 Uranium-238 pCi/g 1.27 +/-0.308 1.33 +/-0.349 2.68 +/-0.462 0.961 +/-0.273 0.509 +/-0.220 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g -0.65800 U +/-1.03 1.02 J +/-1.72 0.799 U +/-3.13 0.513 U +/-0.793 -0.18200 U +/-1.00 Uranium-235 pCi/g 0.0755 U +/-0.0524 0.211 +/-0.100 0.287 +/-0.240 0.0501 U +/-0.0532 0.137 U +/-0.0663 SDG # L1272198 L1272198 L1272198 L1272198 L1272198 Location ID: UNC-46 UNC-47 UNC-48 UNC-49 UNC-50 Date Collected: 10/01/20 10/01/20 10/01/20 10/01/20 10/01/20 Sample Name: Units UNC-46 10012020 UNC-47 10012020 UNC-48 10012020 UNC-49 10012020 UNC-50 10012020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.10 +/-0.390 0.876 +/-0.282 1.10 +/-0.311 0.704 +/-0.253 0.640 +/-0.313 Uranium-235 pCi/g -0.009540000 +/-0.108 0.00938 +/-0.0783 0.146 +/-0.120 0.0450 +/-0.0791 0.119 +/-0.118 Uranium-238 pCi/g 0.291 +/-0.201 0.500 +/-0.204 0.716 +/-0.266 0.740 +/-0.253 0.768 +/-0.258 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.825 J +/-0.717 0.196 U +/-0.628 0.0253 U +/-0.702 0.219 U +/-0.693 0.217 U +/-0.663 Uranium-235 pCi/g 0.0542 U +/-0.0349 0.0792 U +/-0.0826 0.147 U +/-0.0873 0.0495 J +/-0.0526 0.0626 +/-0.0507 SDG # L1272198 L1272198 L1272198 L1272198 L1272198 Location ID: UNC-51 UNC-52 UNC-53 UNC-54 UNC-55 Date Collected: 10/01/20 10/01/20 10/01/20 10/01/20 10/01/20 Sample Name: Units UNC-51 10012020 UNC-52 10012020 UNC-53 10012020 UNC-54 10012020 UNC-55 10012020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.637 +/-0.277 1.21 +/-0.392 0.941 +/-0.375 21.1 +/-1.09 3.21 +/-0.507 Uranium-235 pCi/g 0.0567 +/-0.111 0.0593 +/-0.127 0.0610 +/-0.122 1.35 +/-0.275 0.132 +/-0.144 Uranium-238 pCi/g 0.408 +/-0.189 1.85 +/-0.378 0.777 +/-0.281 1.31 +/-0.285 0.650 +/-0.239 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.320 U +/-0.467 1.47 J +/-1.84 0.713 J +/-0.883 1.83 J +/-1.35 0.720 U +/-0.708 Uranium-235 pCi/g 0.0967 U +/-0.0505 0.244 +/-0.113 0.0228 U +/-0.324 1.16 +/-0.132 0.136 U +/-0.0409 SDG # L1272198 L1272198 L1272198 L1272198 L1271690 Location ID: UNC-56 UNC-57 UNC-58 UNC-59 UNC-60 Date Collected: 10/01/20 10/01/20 10/01/20 10/01/20 10/02/20 Sample Name: Units UNC-56 10012020 UNC-57 10012020 UNC-58 10012020 UNC-59 10012020 UNC-60 10022020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.27 +/-0.349 2.06 +/-0.387 0.643 +/-0.295 0.258 +/-0.245 0.716 +/-0.301 Uranium-235 pCi/g 0.0291 +/-0.128 0.148 +/-0.123 0.112 +/-0.111 0.0551 +/-0.126 0.126 +/-0.126 Uranium-238 pCi/g 1.00 +/-0.275 0.453 +/-0.187 0.503 +/-0.258 0.300 +/-0.230 0.406 +/-0.190 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g -0.29600 U +/-0.902 -0.23200 U +/-1.16 0.362 U +/-0.702 -0.0137000 U +/-0.330 0.00799 U +/-0.675 Uranium-235 pCi/g 0.116 U +/-0.0510 0.274 +/-0.0918 -0.0149000 U +/-0.289 0.0383 +/-0.0256 0.105 U +/-0.0901 FSS Sample Results.xlsx Page 3 of 6 12/10/2020

Table 2 Summary of UNC Sample Analytical Results SDG # L1271690 L1271690 L1271690 L1271690 L1271690 Location ID: UNC-61 UNC-62 UNC-63 UNC-64 UNC-65 Date Collected: 10/02/20 10/02/20 10/02/20 10/02/20 10/02/20 Sample Name: Units UNC-61 10022020 UNC-62 10022020 UNC-63 10022020 UNC-64 10022020 UNC-65 10022020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.76 +/-0.376 1.32 +/-0.330 1.09 +/-0.317 1.05 +/-0.307 1.01 +/-0.351 Uranium-235 pCi/g 0.126 +/-0.0977 0.295 +/-0.182 0.0788 +/-0.134 0.0696 +/-0.110 0.0151 +/-0.145 Uranium-238 pCi/g 0.361 +/-0.177 0.426 +/-0.199 0.599 +/-0.207 0.810 +/-0.260 0.590 +/-0.297 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.586 J +/-0.967 0.123 U +/-0.707 0.794 J +/-0.536 0.0329 U +/-0.710 0.0616 U +/-0.594 Uranium-235 pCi/g 0.0991 +/-0.0603 0.0765 J +/-0.0750 0.0900 U +/-0.0542 0.126 U +/-0.0437 0.105 U +/-0.0789 SDG # L1271690 L1271690 L1271690 L1271690 L1271690 Location ID: UNC-66 UNC-67 UNC-68 UNC-69 UNC-70 Date Collected: 10/02/20 10/02/20 10/02/20 10/02/20 10/02/20 Sample Name: Units UNC-66 10022020 UNC-67 10022020 UNC-68 10022020 UNC-69 10022020 UNC-70 10022020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.857 +/-0.370 0.669 +/-0.333 2.30 +/-0.515 2.57 +/-0.479 2.61 +/-0.495 Uranium-235 pCi/g 0.126 +/-0.125 0.0403 +/-0.0972 0.127 +/-0.141 0.114 +/-0.180 0.0344 +/-0.105 Uranium-238 pCi/g 0.631 +/-0.279 0.669 +/-0.262 0.593 +/-0.289 1.21 +/-0.340 0.854 +/-0.275 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.401 U +/-0.459 0.220 U +/-0.595 -0.0109000 U +/-0.662 0.996 J +/-0.887 0.129 U +/-0.741 Uranium-235 pCi/g 0.0546 U +/-0.0483 0.0805 U +/-0.0340 0.316 U +/-0.101 0.150 +/-0.0612 0.111 +/-0.0543 SDG # L1271690 L1271690 L1271690 L1271690 L1271680 Location ID: UNC-71 UNC-72 UNC-73 UNC-74 UNC-75 Date Collected: 10/02/20 10/02/20 10/02/20 10/02/20 10/05/20 Sample Name: Units UNC-71 10022020 UNC-72 10022020 UNC-73 10022020 UNC-74 10022020 UNC-75 10052020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.639 +/-0.326 0.897 +/-0.329 3.01 +/-0.471 1.79 +/-0.416 1.44 +/-0.345 Uranium-235 pCi/g 0.155 +/-0.144 0.0903 +/-0.117 0.472 +/-0.175 0.0381 +/-0.132 0.0625 +/-0.0996 Uranium-238 pCi/g 0.819 +/-0.265 0.838 +/-0.265 2.05 +/-0.365 1.07 +/-0.327 0.970 +/-0.273 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.0742 U +/-0.431 0.418 U +/-0.708 0.422 U +/-0.646 0.195 U +/-1.07 0.279 +/-0.753 Uranium-235 pCi/g 0.115 U +/-0.0480 0.0509 U +/-0.0366 0.0779 U +/-0.0858 0.274 +/-0.0859 0.415 +/-0.0808 SDG # L1271680 L1271680 L1271680 L1271680 L1271680 Location ID: UNC-76 UNC-77 UNC-78 UNC-79 UNC-80 Date Collected: 10/05/20 10/05/20 10/05/20 10/05/20 10/05/20 Sample Name: Units UNC-76 10052020 UNC-77 10052020 UNC-78 10052020 UNC-79 10052020 UNC-80 10052020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.638 +/-0.248 0.995 +/-0.293 0.661 +/-0.302 1.04 +/-0.305 0.667 +/-0.320 Uranium-235 pCi/g 0.107 +/-0.107 0.119 +/-0.108 0.0505 +/-0.0878 0.0668 +/-0.108 -0.009430000 +/-0.0984 Uranium-238 pCi/g 0.329 +/-0.204 0.405 +/-0.204 0.461 +/-0.196 0.763 +/-0.232 0.921 +/-0.271 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.0149 +/-0.465 -0.0612000 +/-0.518 0.513 +/-0.743 0.617 +/-0.741 0.692 +/-0.696 Uranium-235 pCi/g 0.0512 +/-0.0346 0.0399 +/-0.217 0.0944 +/-0.0838 0.0946 +/-0.0389 0.115 +/-0.0829 FSS Sample Results.xlsx Page 4 of 6 12/10/2020

Table 2 Summary of UNC Sample Analytical Results SDG # L1271680 L1271680 L1271680 L1271680 L1271680 Location ID: UNC-81 UNC-82 UNC-83 UNC-84 UNC-85 Date Collected: 10/05/20 10/05/20 10/03/20 10/05/20 10/05/20 Sample Name: Units UNC-81 10052020 UNC-82 10052020 UNC-83 10032020 UNC-84 10052020 UNC-85 10052020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.32 +/-0.365 0.258 +/-0.225 0.784 +/-0.262 0.922 +/-0.292 1.42 +/-0.358 Uranium-235 pCi/g 0.220 +/-0.150 0.0624 +/-0.0744 0.0318 +/-0.114 0.00753 +/-0.111 0.0725 +/-0.114 Uranium-238 pCi/g 1.20 +/-0.306 0.645 +/-0.212 0.681 +/-0.246 1.30 +/-0.295 1.29 +/-0.330 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.190 +/-0.909 0.0339 +/-0.538 0.0800 +/-0.562 0.786 +/-0.787 0.492 +/-1.10 Uranium-235 pCi/g 0.0763 +/-0.0557 0.0187 +/-0.0403 -0.0264000 +/-0.254 0.135 +/-0.0678 0.106 +/-0.0681 SDG # L1271680 L1271680 L1271680 L1271680 L1271101 Location ID: UNC-86 UNC-87 UNC-88 UNC-89 UNC-90 Date Collected: 10/05/20 10/05/20 10/05/20 10/05/20 10/02/20 Sample Name: Units UNC-86 10052020 UNC-87 10052020 UNC-88 10052020 UNC-89 10052020 UNC-90 10022020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.529 +/-0.246 1.58 +/-0.438 0.427 +/-0.275 1.53 +/-0.410 2.49 +/-0.393 Uranium-235 pCi/g -0.0299000 +/-0.105 0.0561 +/-0.0961 0.125 +/-0.125 0.0308 +/-0.0965 0.0316 +/-0.0878 Uranium-238 pCi/g 0.224 +/-0.199 0.614 +/-0.272 0.584 +/-0.233 0.442 +/-0.243 0.351 +/-0.159 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g -0.0241000 +/-0.553 0.173 +/-0.659 -0.0498000 +/-0.450 0.332 +/-0.563 0.418 +/-0.352 Uranium-235 pCi/g 0.0377 +/-0.0294 0.249 +/-0.0921 -0.10600 +/-0.192 0.0467 +/-0.0554 0.129 +/-0.0368 SDG # L1271101 L1271101 L1271101 L1271101 L1271101 Location ID: UNC-91 UNC-92 UNC-93 UNC-94 UNC-95 Date Collected: 10/02/20 10/02/20 10/02/20 10/02/20 10/02/20 Sample Name: Units UNC-91 10022020 UNC-92 10022020 UNC-93 10022020 UNC-94 10022020 UNC-95 10022020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 1.30 +/-0.340 3.25 +/-0.513 0.697 +/-0.240 1.28 +/-0.314 0.328 +/-0.217 Uranium-235 pCi/g 0.0600 +/-0.105 0.120 +/-0.120 0.0876 +/-0.0745 0.0856 +/-0.124 -0.0439000 +/-0.0957 Uranium-238 pCi/g 0.705 +/-0.225 1.23 +/-0.304 0.529 +/-0.176 0.552 +/-0.214 0.656 +/-0.214 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.0320 +/-0.428 0.0233 +/-0.321 0.0272 +/-0.416 0.559 +/-0.804 0.260 +/-0.629 Uranium-235 pCi/g 0.117 +/-0.0435 0.0990 +/-0.145 0.0373 +/-0.0406 0.0838 +/-0.0555 0.0620 +/-0.0452 SDG # L1271101 L1271101 L1271101 L1271101 L1271101 Location ID: UNC-96 UNC-97 UNC-98 UNC-99 UNC-100 Date Collected: 10/02/20 10/02/20 10/02/20 10/02/20 10/02/20 Sample Name: Units UNC-96 10022020 UNC-97 10022020 UNC-98 10022020 UNC-99 10022020 UNC-100 10022020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 0.460 +/-0.213 0.442 +/-0.223 1.53 +/-0.418 1.48 +/-0.378 5.84 +/-0.689 Uranium-235 pCi/g -0.0278000 +/-0.0624-0.0670000 +/-0.0842 0.0114 +/-0.0703 0.0301 +/-0.0775 0.125 +/-0.125 Uranium-238 pCi/g 0.496 +/-0.201 0.653 +/-0.261 0.663 +/-0.269 0.731 +/-0.242 2.18 +/-0.428 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.243 +/-0.317 0.599 +/-0.562 0.361 +/-0.766 0.561 +/-0.737 0.416 +/-0.662 Uranium-235 pCi/g-0.00042000000 +/-0.1300.0325 +/-0.0471 0.108 +/-0.0413 0.0723 +/-0.0524 0.187 +/-0.0555 FSS Sample Results.xlsx Page 5 of 6 12/10/2020

Table 2 Summary of UNC Sample Analytical Results SDG # L1271101 L1271101 L1271101 Location ID: UNC-101 UNC-102 UNC-103 Date Collected: 10/02/20 10/02/20 10/05/20 Sample Name: Units UNC-101 10022020UNC-102 10022020UNC-103 10052020 Radiochem-Alpha Spectroscopy Uranium-234 pCi/g 5.06 +/-0.564 6.80 +/-0.768 1.38 +/-0.377 Uranium-235 pCi/g 0.179 +/-0.156 0.229 +/-0.164 0.0941 +/-0.121 Uranium-238 pCi/g 0.921 +/-0.258 0.996 +/-0.294 1.38 +/-0.346 Radiochem-Gamma Spectroscopy Thorium-234 pCi/g 0.217 +/-0.449 0.473 +/-0.607 0.170 +/-1.05 Uranium-235 pCi/g 0.118 +/-0.0457 0.347 +/-0.0986 0.114 +/-0.0602 FSS Sample Results.xlsx Page 6 of 6 12/10/2020

FIGURES 71 Shelton Ave City: Div/Group: Created By: Last Saved By: MSMiller Project (Project #)

UNC FACILITY NOTE: NEW HAVEN AERIAL IMAGE PROVIDED BY GOOGLE EARTH PRO D:\NewHaven\MXD\Update\Figure 1 UNC New Haven Site.mxd 11/17/2020 9:51:03 AM CONNECTICUT UNC New Haven Site 71 Shelton Avenue, New Haven, Connecticut 0 100 200 FIGURE 1

Feet GRAPHIC SCALE

N GIBBS STREET SHELTON AVENUE 50H 41H 19H 44H 11H 10H 9H 8H 7H 14H City: Div/Group: Created By: Last Saved By: MSMiller 6H 3H ARGYLE STREET Project (Project #)

NOT TO SCALE UNC FACILITY D:\NewHaven\MXD\Update\Figure 2 UNC BUILDING IN THE H TRACT.mxd 12/2/2020 10:01:59 AM NEW HAVEN NOTES: CONNECTICUT UNC BUILIDNGS: 3H, 6H, 7H, 8H, 9H, 10H, 11H, 14H, 44H BUILDINGS IN THE H TRACT GULF ATOMIC BUILDINGS: 19H, 41H, 50H FIGURE 2

C:\Users\lposenauer\BIM 360\Arcadis\ANA - GE CORP ENV PROG\Project Files\GE UNC NEW HAVEN - ENGINEERING\2020\30006255\01-DWG\GE-UNC_FSS_03_BLDG 6H and 3H.dwg LAYOUT: 3 SAVED: 11/20/2020 2:27 PM ACADVER: 23.1S (LMS TECH) PAGESETUP: C-LD-PDF PLOTSTYLETABLE:

RM FA 91 SHELTON AVENUE IN O

GT N

CA LG 12" WIDE CONCRETE WALL DOUBLE SWING CHAIN NA LINK GATE RE W

EN AY FORMER CONC SIDEWALK PARKING AREA SHELTON AVENUE 71 SHELTON AVENUE GRAVEL AND CONCRETE DECON ACCESS ROAD AREA ELEMENT PICKLE CONCRETE MANUFACTURING X-RAY AREA BUILDING 6H WEST BUILDING 6H EAST BUILDING 3H POWDER MACHINING FACILITY AREA CHEMISTRY X-RAY VAULT LAB READING ROOM ARGYLE ST.

CONCRETE CURB PLTFULL.CTB PLOTTED: 11/20/2020 4:28 PM BY: POSENAUER, LISA 201 MUNSON STREET UNC FACILITY NEW HAVEN, CONNECTICUT BUILDING 6H AND 3H FIGURE 3

Area 6 Laydown Area and Haul Road.

Area 2 Former Building 7H, 8H, 14H Area 1 Former Building 9H, 10H, 11H Area 5 Building 3H Area 4 Building 6H Center Area 3 Building 6H West Area 7 South Trench/Southern Boundary City: Div/Group: Created By: Last Saved By: MSMiller Project (Project #)

D:\NewHaven\MXD\Update\Figure 4 Final Status Survey Sample Locations.mxd 12/4/2020 10:43:38 AM UNC FACILITY LEGEND NEW HAVEN CONNECTICUT SURVEY UNIT BOUNDARY UNC SAMPLE LOCATION FINAL STATUS SURVEY SAMPLE LOCATIONS D

0 80 160 FIGURE 4

Feet GRAPHIC SCALE

Area 1 Former Building 9H, 10H, 11H Area 2 Former  ! ! Building 7H, 8H, 14H Area 3 Building 6H West Area 4 Building 6H Center Area 6 Laydown Area and Haul Road.

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