ML090641013

Nasa Plum Brook Station - Sediment Characterization Data Summary

ML090641013
Person / Time
Site:	Plum Brook
Issue date:	10/29/2008
From:	Peecook K US National Aeronautics & Space Admin (NASA), John H. Glenn Research Ctr at Lewis Field
To:	Document Control Desk, NRC/FSME
References
Download: ML090641013 (22)

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National Aeronautics and Space Administration John H. Glenn Research Center Lewis Field Plum Brook Station Sandusky, OH 44870 October 29, 2008 Reply to Attn of: QD U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

Subject:

Plum Brook Sediment Characterization Data Summary for the Plum Brook Reactor Facility, Licenses Nos. TR-3, Docket No. 50-30 and R-93, Docket No, 50-185 In response to the issues discussed at the public meeting regarding Plum Brook Characterization and Sample Results held on September 3, 2008 at the Huron Public Library, we are submitting a summary report of the sampling and characterization data from Plum Brook.

Enclosure 1 is a written report that summarizes the data collected from the entire length of the stream from Plum Brook Station to Sandusky Bay. Enclosures 2 through 4 are compact discs containing sample and survey data. These discs include data previously submitted in a series of six reports prepared by our contractor, Haag Environmental Company. In addition, they include data from the first 1.5 mile section of Plum Brook that were not included in the Haag Environmental reports.

We will follow up this summary report with a final detailed Plum Brook Characterization Report and a final report on the dose pathway analyses. The final dose pathway analyses will present a final refinement, contained in a single report, of the dose models previously submitted in Technical Basis Documents PBRF-TBD-07-005 and PBRF-TBD-08-001 (our letters of June 27, 2008 and August 7, 2008). The final dose assessment report will incorporate the guidance presented at the September 3, 2008 meeting in the presentation titled "NRC's Review Process and Expectations for Dose Assessments".

Should you have any questions or need additional information, please contact me at NASA Plum Brook Station, 6100 Columbus Avenue, Sandusky, Ohio 44870, or by telephone at (419) 621-3277.

Sincerely, Keith M. Peecook NASA Decommissioning Program Manager 04oz

2 Enclosures (4)

1. Plum Brook Sediment Characterization Data Summary Report

2. Disc 1, Survey Requests SR 5 thru 12, 19 thru 22, 33 thru 35, 39, 41, 43, and 44

3. Disc 2, SurveyRequests SR 45 thru 49, 53, 54, and 95

4. Disc 3, Data Package SVI-04 cc:

USNRC/C. J. Glenn (FSME)

USNRC/J. Webb (FSME)

USNRC/K. E. Pinkston (FSME)

USNRC/W. G. Snell RIII/DNMS/DB USNRC/P. J. Lee RIII/DNMS/DB ODH/M. J. Rubadue

SAFETY AND MISSION ASSURANCE DIRECTORATE Plum Brook Reactor Facility Plum Brook Sediment Characterization Data Summary October 2008

Plum Brook Sediment Characterization Data Summary Table of Contents 1.0 In tro d u ctio n ..................................................................... ................................................ 1 2.0 Plum Brook Characterization Survey Packages ......................................................... 1 2.1 Index of Survey Packages ....................................................................................... 2 2.2 Contents of a Typical Survey Package ................................................................... 4 3.0 Summary of Survey Packages and Results ................................................................. 5 3.1 Initial Scoping Survey - All Stream Sections ........................................................ 5 3.2 Stream Section 1 - PBRF to US Rt. 2 .................................................................. 7 3.3 Property Adjacent to the Plum Brook in Stream Section 1 ...................................... .9 3.4 Stream Section 3 - PBCC to US Rt. 6 ................................................................... 10 3.5 Stream Section 4 - Stream Mouth and Wetlands ..................................................... 13 3.6 Sandusky B ay ...................................................................................................... . . 14 3.7 PBRF Site Investigation Surveys ......................................................................... 15 Attachment 1 - List of Survey Packages with Page Count ................................................... 17 Attachment 2 - List of Procedures ..... .................................................................................. 18 List of Tables Table 1, Plum Brook Characterization Survey Packages ......................................................... 2 Table 2, Plum Brook Cs-137 Concentration Trends (pCi/g) ..................................................... 6 Table 3, Cs-137 Concentrations vs. Downstream Distance in Section 1................................... 7 Table 4, Summary of Sample Results for Section 1 Stream Bank Investigation ...................... 8 Table 5, Section 1 Bounding Survey Sample Analysis Results ................................................. 8 Table 6, Cs-137 Concentrations vs. Downstream Distance - all data ........................................ 8 Table 7, Cs-137 Depth Concentration Profiles for Section 1 ................... .................................. 9 Table 8, Summary of Sample Results from Stream Section 3 ................................................. 10 Table 9, Summary of PBCC Sample Results ........................................... 11 Table 10, Cs-137 Depth Profiles from PBCC Samples (pCi/g) ............................................... 13 Table 11, SR-39 Depth Profiles for Cs-137 (pCi/g) ................................................................. 14 Table 12, WEMS Outfall Sediment Depth Profile ................................................................... 15 Table 13, Sediment Depth Profiles for Eastern Pentolite Ditch .............................................. 15 List of Figures Figure 1, Concentration vs. Downstream Distance .................................................................. 6 Enclosure I to letter dated October 29, 2008 i

Plum Brook Sediment Characterization Data Summary 1.0 Introduction This report describes characterization survey data obtained from the.Plum Brook and Environs during the period from September 2005 through January 2008. These data are provided to the US Nuclear Regulatory Commission (NRC) as initial supporting information for forthcoming submittals to demonstrate that the Plum Brook satisfies the 25 millirem per year dose criterion in 10CFR20 Subpart E for release of sites for unrestricted use.

Extensive sampling campaigns were conducted to determine the levels and extent of radioactivity contamination in the Plum Brook. The characterization was performed under approved procedures. Radiological survey, soil and sediment sampling information are maintained in procedure-controlled survey packages. Altogether, 28 survey packages were established for the Plum Brook characterization. The initial scoping survey of the entire Plum Brook downstream of the PBRF was performed in 2005 under the then-existing PBRF Procedure Manual. This initial survey Package is identified as SVI-04. Subsequent survey packages are identified as "Survey Requests" (SRs), prepared under the revised PBRF Procedure Manual.

These comprise 27 SRs which cover the Plum Brook and environs between the PBRF and Sandusky Bay. They include two SRs, which cover sampling within the PBRF.

The 28 survey packages developed for Plum Brook characterization comprise over 2400 pages1 .

Each package includes results of laboratory analysis and a summary of the results for samples collected under the package. Analysis of the data is in progress to support the dose assessment.

This should be kept in mind when attempting to draw detailed conclusions on levels and spatial distribution of Cs-137 and Co-60 in the Plum Brook and environs.

This report is provided to aid reviewers of the survey package information. A tabular summary and index of the attached survey packages is provided. The contents of a typical survey package are described. This is followed by a summary of the sample results for each group of survey packages associated with the major stream sections.

2.0 Plum Brook CharacterizationSurvey Packages The Plum Brook Sampling campaign was conducted in phases. These phases included scoping, characterization and investigative surveys. The data life cycle for each survey is documented in a survey package (Survey Request). The survey and sampling activities for all phases were conducted under approved PBRF FSS/Characterization procedures. A list of the applicable procedures is provided in Attachment 2.

The 28 survey packages are contained on three CDs. See Attachment 1 for a listing of the packages and a page count.

Enclosure I to letter dated October 29, 2008 I

Plum Brook Sediment Characterization Data Summary 2.1 Index of Survey Packages The survey packages developed for Plum Brook characterization are identified and indexed in Table 1. The table lists them by the assigned ID Number in ascending order, gives the location of the area under investigation, the sampling design basis, the number of samples collected, the number of locations sampled, type of samples (sample matrix) and the stream section. The Plum Brook between the PBRF and Sandusky Bay was divided into sections for development of exposure scenarios used in Plum Brook dose assessments. The stream section designator, 0, is used to designate survey packages established for areas not immediately adjacent to the Plum I Brook, but related to the Plum Brook investigation. Section 1 designates the stream from the Plum Brook Station northern boundary to US Rt. 2; Section 2 lies between US Rt. 2 and the mid-portion of the Plum Brook Country Club (PBCC); Section 3 includes the upper flood plain extending from the PBCC to US Rt. 6 and Section 4, the stream-mouth floodplain and wetlands, extends from US Rt. 6 to-Sandusky Bay.

It is seen in Table 1, that in most cases the number of samples is greater than the number of locations sampled. In this compilation, the number of samples refers to the number of material sub-samples analyzed for radioactivity concentration. At most of the locations sampled, sub-samples were collected for analysis of concentration Vs depth, typically through the use of core samplers.

Table 1, Plum Brook Characterization Survey Packages ID No. & Stream Course Sampling No. of No of Type o Stream Description Location Design Basis Samples Locations Samples Section Sampled SVI-04 PBRF to Sandusky Judgment 85 15 Surface 1,2,3, Bay J sediment 4 SR-5 (Sect A Pentolite Rd to surface and P51 c Cela Rd t random (syst) 180 57 subsurface 1 Ph 1) Clark Rd sediment/soil Clark Rd to surface and SR-6 (Sect B Taylorbrook Ln., random (syst) 271 92 subsurface 1 Ph 1) sediment/soil surface and SR-7 (Sect C Taylorbrook Ln. to random (syst) 279 91 subsurface 1 Ph 1) Bogart Rd. sediment/soil surface and SR-8 (Sect D Bogart Rd. to Rt. random (syst) 91 29 subsurface 1 Ph 1) 250 sediment/soil Pentolite Rd to from banks w. surfaceand surface 1 SR-9 (Sect A Clark Rd elevated scans sediment/soil Ph 2)

Enclosure I to letter dated October 29, 2008 2

Plum Brook Sediment Characterization Data Summary ID No. & Stream Course Sampling No. of No of Type of Stream Description Location Design Basis Samples Locations Samples Section Sampled.

surface surfaceand 1 SR-10 (Sect Clark Rd to from banks w.

Taylorbrook Ln., elevated scans sediment/soil B Ph 2) surface and from banks w. surface 1 SR-Il (Sect Taylorbrook Ln. to Bogart Rd. elevated scans sediment/soil C Ph 2) surface surfaceand 1 SR-12 (Sect Bogart Rd. to Rt. from banks w.

250 elevated scans sediment/soil D Ph 2) surface and SR-19 (Sect Random (syst) 142 45 subsurface 1 E Ph 1) Rt. 250 to Rt. 2 sediment/soil surface and SR-20 (Sect Rt. 250 to Rt. 2 from banks w. 64 20 subsurface 1 E Ph 2) - elevated scans sediment/soil Former WWT random start -

SR-21 facility property on triangular grid 17 16 surface soil Taylor Rd Residential yards, judgment and SR-22 adjacent to Plum biased using 11 10 surface soil 1 Brook scan results surface and SR-33* PBCC Ponds judgment 41 11 subsurface 3 investigative sediment/soil surface and SR 34* Sandusky Bay systematic 142 44 subsurface 4 sediment/soil Groundwater wells biased - water and SR-35 ondPBRF available wells 18 17 suspended 0 sediment judgment- surface and US Rt. ý6 to SR-39* S 6 ta judgmat- 312 64 subsurface 4 Sandusky Bay systematic sediment/soil judgment and surface and Center of PBCC to SR-41

• Rt . 6 scans 313 64 subsurface 3 US Rt. 6 scans sediment/soil surface and SR-43 Pentolite Ditch judgment 42 8 subsurface 0 sediment/soil Investigation of biased - surface and SR-44* Selected Areas in 90 *21 subsurface 4 SR 39 investigative sediment/soil Enclosure I to letter dated October 29, 2008 3

Plum Brook Sediment Characterization Data Summary No of ID No. & Stream Course Sampling No. of Locations Type o Stream Description Location Design Basis Samples Sampled Samples Section SR-45 (Sect Pentolite Rd to investigate and surface and AR-4 Bonig Clark Rd t bound elev. 184 72 subsurface 1 areas sediment/soil SR-46 (Sect Clark Rd to investigate and surface and BR4 BB Sect Bounding) Clarbrk Taylorbrook Rd tobound Ln.,arsseintol elev. 31 14 subsurface 1 areas sediment/soil SR-47 (Sect Taylorbrook Ln. to investigate and surface and Bogart Rd. bound elev. 57 46 subsurface 1 C Bounding)

____________areas ______sediment/soil_____

D Bounding) 250rtRd SR-48 (Sect Bogart Rd. to Rt. investigate and surface and DBudn)20bound elev. 45 13 subsurface 1 areas sediment/soil investigate and surface and SR-4E (Sect Rt. 250 to Rt. 2 bound elev. 65 19 subsurface 1 areas sediment/soil Additional surface and SR-53* Investigation of biased " 219 36 subsurface 4 Selected Areas in investigative sediment/soil SR 39 Perkins Ave to US random start surface and SR-54 Rt. 6 triangular grid 212 42 subsurface 3 sediment/soil Former WWT biased to cover surface and SR-95 facility property on former plant 20 70 subsurface 1 Taylor Rd tank locations soil Table I note: Datafrom the six survey packages marked with an asterisk (SR-33, SR 34, SR-39, SR-41, SR-44 and SR-53) are contained in contractorreports that have been previously submitted to the US Nuclear Regulatory Commission.

2.2 Contents of a Typical Survey Package This description describes the contents of a typical survey package, a Survey Request, as these constitute the majority of the survey packages 2. A typical survey request is of a standard format and includes the following:

0 Survey Request Form*

0 Survey Design Package or Sampling Plan (if applicable) 0 Radiological Survey Reports (Radiation Protection Survey Form) 0 Maps, photos and other supporting-descriptive information 2 The SVI-04 scoping survey was conducted under Procedure RP-600, "PBRF Verification Survey Program",

replaced by Procedure CS-01 in late 2005.

Eiclosure I to letter dated October 29, 2008 4

Plum Brook Sediment Characterization Data Summary

• Survey Request Sample Analysis Sheet

• Field Sample Collection and Chain of Custody Log and COC Forms

" Quality Checking Inspection Form*

• Survey Data Verification and Validation Form*

" Survey Request Close-Out Summary*

• Job Safety Analysis*

• Pre-job Briefing Checklist and Attendance Sheet Those items in the list above marked with an asterisk are the minimum required in an SR per Procedure CS-01. In addition, for SRs involving specialty subcontractors or the use of specialized sampling equipment, contractor's Health and Safety and QA Plans and equipment operating procedures may be included in the SR package.

3.0 Summary of Survey Packagesand Results A summary of the Plum Brook surveys is provided below by discussing groups of packages that cover each major stream section. The initial scoping survey is summarized followed by summaries of the packages that cover each of the major stream sections. As seen below, the survey of the major stream sections proceeded in phases.

3.1 Initial Scoping Survey - All Stream Sections Package SVI Plum Brook Creek Bed The initial scoping survey was conducted in the fall of 2005. It was designed to determine if residual radioactivity from PBRF was present in the Plum Brook Creek downstream of the confluence with Pentolite Ditch. Samples were collected along the entire stream course from Pentolite road in the PBRF to the crossing at US Rt. 6 near the stream mouth. Locations were identified along the Brook where the stream bed could be safely accessed and did not require crossing private property. These access points were primarily where the Brook passed through culverts under roadways. A scan survey was performed in at least two areas at each access point using the Ludlum 2350-1 data logger with 2x2 in sodium iodide (Nal) detector and Cs-137 energy window setting. The window was approximately 100 kev wide centered on the Cs-137 (Ba-137) 662 key full energy peak. Soil samples were collected at each area where gamma activity was observed above 300cpm. A minimum of two core samples were required at each designated access location. Samples were collected at 0-6", 7-12", and 13-18" depths, if possible.

Four background sample locations were also identified in several similar streams in or near the Plum Brook watershed.

Results from the initial samples (32 samples collected from survey Locations 1-6) showed evidence of impact from PBRF operations. The highest activity measured was 38.3 pCi/g Cs-137 at Location 5 (Taylorbrook Road). This was from a QC replicate sample from core No. 1 at that location, at depth 13 to 18 in. The average activity of all 32 samples collected from Locations 1-6 was 7.9 +1.2 pCi/g Cs-137. Eighteen samples had measurable Co-60 with the highest of 0.45 pCi/g and the average of 0.19 +/-0.02 pCi/g. Subsequently, the scope of the SVI was expanded to include the remainder of the Brook upstream and down stream of the initial Enclosure I to letter dated October 29, 2008 5

Plum Brook Sediment Characterization Data Summary sample area. The expanded sampling effort included 22 samples from Locations 7-10 downstream of Bogart Road and 19 samples from the Plum Brook upstream of Pentolite Road from Locations 11-14. Twelve samples were collected at two locations in the vicinity of the old Wastewater Treatment Facility on Taylor Road and 15 background samples were taken in various stream beds other than Plum Brook Creek at Locations B-I to B-4. None of the additional samples showed activity higher than Location 5. The average Cs-137 activity from all locations was 5.2 -0.6 pCi/g. The average Cs-137 activity from the background locations was 0.14 +0.01 pCi/g.

Trends in Plum Brook sediment Cs-137 concentration vs. downstream distance from Pentolite ditch are shown in Table 2. Results for all the samples collected from the 11 locations sampled between the junction with Pentolite Ditch and Sandusky Bay are included. Note that two cores were collected at each location. The average concentrations for each of the 11 locations are the average of all concentrations at all depths. Concentrations at each depth are calculated as the average of the two core results from that depth. The concentration trends are shown graphically in Figure 1.

Table 2, Plum Brook Cs-137 Concentration Trends (pCi/g)

Location Location Cumulative Cumulative No. Description Distance (mi) Distance (m) Avg. 0"-6" 7"-12" 13"-18" 2 Pentolite Rd 0.02 32 2.6 2.7 2.4 2.8 3 Columbus Rd 0.24 386 4.6 4.4 4.2 5.3 4 Clark Rd 0.33 531 1.6 1.7 1.6 1.4 15 WWTS 1 0.79 1271 15.7 19.6 11.8 NR 16 WWTS 2 0.8 1287 9.1 10.1 8.1 NR 5 Taylorbrook Rd 1 1609 22.1 28.0 11.7 22.7 6 Bogart Rd 1.16 1867 6.6 16.1 3.1 4.0 7 Galloway Rd 2.42 3895 0.5 0.4 0.6 NR 8 Hull Rd 2.87 4619 0.3 0.2 0.3 0.3 9 Perkins Ave 3.6 5794 0.4 0.3 0.3 0.5 10 Rt. 6 3.84 6180 1.1 0.4 0.8 2.2 Figure 1, Concentration vs. Downstream Distance 100.0 10.0 0

0 1.0 Enc 0.1 0.0 0.2 0.3 0.8 0.8 1.0. 1.2 2.4 2.9 3.6 3.8 uownstream uistance (mi)

Plum Brook Sediment Characterization Data Summary 3.2 Stream Section 1 - PBRF to US Rt. 2 For characterization survey purposes, the Plum Brook stream located between the juncture with the Pentolite Ditch and US Rt. 2 was divided into five sections, designated as Sections A through E, averaging 1700 ft. in length.

Phase I Characterization Survey Sections A Through E - Packages SR-5, SR-6, SR-7, SR-8 &

SR-19 (November 2005 - June 2006)

This phase of the Plum Brook Characterization covered the stream bed and banks from Pentolite Road to US Route 2, a stream course distance of approximately 1.6 miles. The sampling locations in these sections were established on a triangular grid pattern with a randomly selected starting point. Sampling locations were established at 25 ft. intervals along the stream course, alternating between the stream center and each bank (eight ft. from the stream center). This resulted in core samples collected at 100 foot intervals from the stream center and at 100 foot intervals along each bank. A total of 963 samples (including - 5% QC split samples) were collected from 314 locations. Samples were collected from depths 0 to 6, 6 to 15, and 15 to 24 inches (or to refusal).

Cesium-137 was measured at concentrations > MDA in 86% of the samples. The average concentration in all samples was 1.2 pCi/g and the maximum concentration was 38.3 pCi/g.

Cobalt-60 was measured at concentrations > MDA in 14% of the samples. The average concentration was 0.1 pCi/g and the maximum concentration was 0.8 pCi/g. Table 3 shows the average and maximum concentrations of Cs-137 for each of the subsections A through E. These results are considered to represent "best" estimates of average Cs- 137 concentration in, Section 1 stream sediments as the sample locations were selected in an unbiased manner.

Table 3, Cs-137 Concentrations vs. Downstream Distance in Section 1 ParameterA Stream Section 1 - Subsections BCDB A B C D E Cs-137 Average (pCi/g) 1.3 0.9 1.6 1.2 0.6 Cs-137 Maximum (pCi/g) 38.3 5.7 24.2 27.0 3.2 Phase II Characterization Survey Sections A Through E - Packages SR-9, SR-10, SR-11, SR- 12

& SR-20 Phase II of the survey of Sections A through E was conducted to characterize the stream banks.

The banks were scanned with 2x2 in Nal detectors with energy window set for the 662 kev Cs-137 gamma. Samples were collected at locations where gamma count rates were observed to be

> 3,00 gross counts per minute or otherwise considered to represent areas of elevated activity upon review by the cognizant Radiological Engineer. A total of 465 samples were collected from Enclosure I to letter dated October 29, 2008 7

Plum Brook Sediment Characterization Data Summary 143 locations. Samples were collected from depths 0 to 6, 6 to 15, and 15 to 24 inches (or to refusal). A summary of the sample results is provided in Table 4.

Table 4, Summary of Sample Results for Section 1 Stream Bank Investigation No. of No. of Results > Average Maximum Radionuclide Samples MDA Concentration Concentration Analyzed' Mp~ig) (pCi/g)

Cs-137 465 441 4.3 50.1 Co-60 465 44 0.1 0.5 Bounding Survey of Characterization Survey Sections A Through E - Packages SR-45, SR-46, SR-47, SR-48 and SR-49 These survey packages were developed to further investigate and determine the physical extent (to bound) areas where elevated activity was measured in the Phase I and II surveys. Scan surveys were performed at locations where previous surveys had measured gamma activity > 300 gross counts per minute to delineate the areas. Samples were collected to verify the soil/sediment activity concentrations at the boundaries of the elevated areas and to provide data for elevated measurement comparison (EMC) tests. A total of 382 samples were collected from 164 locations. Samples were collected from depths 0 to 6, 6 to 12, 12 to 18 to 24, 24 to 30 and 30 to 36 inches (or to refusal). The sample analysis results are summarized in Table 5.

Table 5, Section 1 Bounding Survey Sample Analysis Results No. of No. of Results > Average Maximum Radionuclide Samples MDA Concentration Concentration Analyzed (pCi/g) Ci/

Cs-137 382 369 7.9 72.4 Co-60 382 20 0.4 1.6

• Summary of Concentration Profiles in Section 1 Combined data from all three Section 1 survey phases is used to examine concentration profiles in Stream Section 1. Even though the Phase II and Bounding Survey concentration measurements result from biased survey approaches, the combined data provides useful information on overall trends for the stream and stream banks. Table 6 suggests that overall, the' sediment Cs- 137 inventory (and concentrations) in the watershed decrease by a factor of approximately two between the PBRF northern boundary and US Rt. 2.

Table 6, Cs-137 Concentrations vs. Downstream Distance - all data Stream Section 1 - Subsections A B C D E Cs-137 Average (pCi/g) 4.4 1.9 3.2 2.3 2.8 Enclosure I to letter dated October 29, 2008

Plum Brook Sediment Characterization Data Summary Cs-137 Maximum (pCi/g) 72.4 1 27.2 33 43.4 1 29.8 Sediment depth concentration profiles are shown in Table 7 for cores that yielded the highest Cs-137 concentrations among all the Section I samples. It is noted that in 3 of the four cores shown, the highest concentrations are below the 0 to 6 inch depth. This suggests that the cesium-bearing sediments are being buried over time by sediments of lower concentration.

Table 7, Cs-137 Depth Concentration Profiles for Section 1 Location & Survey Location Depth (in.) Section A Section D Depth (in.) Section A Section A Bounding Bounding Phase II Phase I 0-6 57.8 43.4 0-6 1.8 2.9 6-12 72.4 12.7 6-15 50.1 5.5 12- 18 9.8 17.0 15-24 37.3 38.3 18-24 NR 4.1 24-30 NR 3.5 Table 7 note: NR means no sample recovery.

3.3 Property Adjacent to the Plum Brook in Stream Section 1 Characterization of former Waste Water treatment Facility - Packages SR-21 and SR-95 The former waste water treatment facility was located between Plum Brook on the west and Taylor Road on the east just north of the Plum Brook facility. It treated sanitary sewage wastewater that originated from several Plum Brook Station facilities including the PBRF. It was closed in 1995 and demolished in 2004. All the underground structures, including building foundations, tanks and settling basins were removed and the site was backfilled and restored to grade with imported soil. The initial survey, conducted in 2006, comprised 100% surface scan of the 1.2 acre site grounds using 2x2 in. NaI detectors with Ludlum model 2350-1 setup to count Cs-137 662 kev gammas. An action level was established at 300 gross cpm for investigation and possible collection of soil samples. No areas with count rates above the action level were observed. Surface soil samples were collected at 16 locations established on a triangular grid with a randomly selected starting point.

Concentrations above MDA for Cs-137 were measured in nine of the 16 samples. The average and maximum Cs-137 concentrations were 0.09 and 0.4 pCi/g respectively. These results are comparable to local area "background" concentrations in surface soil. Cobalt-60 was not measured above MDA levels.

A survey was conducted in January 2008 to characterize the subsurface soil on the wastewater treatment facility site. Geoprobe core samples were collected at 20 locations selected to target subsurface structures and tanks (removed during demolition) of the former facility. From each core, the 0 to 6 in. depth was collected for analysis, and sample aliquots were collected from one, two and three meter depths (or refusal) below the 0 to 6 in. depth. In all, 73 samples (including 3 QC split samples) were processed and analyzed by gamma spectroscopy. Of these, three were Enclosure I to letter dated October 29, 2008 9

Plum Brook Sediment Characterization 'Data Summary positive (> MDA) for Cs-137 (all in the 0 to 6 in. depth) and none for Co-60. The maximum and average measured Cs-137 concentrations were each 0.2 pCi/g.

Investigation of Properties Adjacent to Plum Brook - Package SR-22 Three properties located adjacent to or near the Plum Brook were investigated in 2006. These included two residences on Bogart Road and two soil piles located near the Plum Brook just north of the Clark Road over-crossing. The soil piles were placed for temporary storage of soil of unknown Origin, and later used in construction of a private overpass of the Plum Brook to gain access to farm fields located west of Plum Brook between Clark Rd. and Bogart Rd. The three locations were scanned using 2x2 in. Nal detectors with Ludlum model 2350-1 window setup to count Cs-137 662 kev gammas. An action level was established at 300 gross cpm for investigation and possible collection of soil samples. The scan survey action level was not exceeded at any of the three locations, but several locations were identified during the surveys where slightly elevated activity was observed by the technician.

Eleven surface soil samples were collected from the three properties; two from each of the soil piles, two from the lawn of one residence and four from the garden of a second residence. Seven of the 11 samples yielded measured Cs- 137 concentrations above the MDA. The maximum activity was 1.8 pCi/g, measured in each of two samples collected from the residence lawn. It is noted that this residence is the site of a former auto repair facility which was converted to a residence in about 2004. The property was landscaped and a former parking lot was converted to lawn using fill, some of which was obtained from the banks of the nearby Plum Brook. The remainder of the samples from all locations measured < 0.3 pCi/g. Cobalt-60 was not detected above the MDA in any of the samples.

3.4 Stream Section 3 - PBCC to US Rt. 6 Characterization Surveys of Plum Brook Lower Stream Flood Plain and Stream Mouth -

Packages SR-41 and SR-54 These packages covered the Plum Brook from the Plum Brook Country Club to Rt. 6, a stream course distance of about 0.85 miles. This part of the stream course corresponds to Stream Section 3, established for the dose assessment conceptual site model. Sampling locations in the flood plain between the PBCC and Rt. 6 were established on systematically spaced transects laid out perpendicular to. the stream course. The objective of this sampling design was to obtain estimates of concentration profiles vs. stream course downstream distance and the lateral distribution across the flood plain, as well as the vertical distribution. A total of 521 samples were collected from 106 locations. One third of the samples analyzed returned positive results (>MDA) for Cs-137 and only one sample showed detectable Co-60 activity. The average Cs-137 Concentration from all samples in Stream Section 3 is 0.56 pCi/g. A summary of the sample results is provided in Table 8.

Table 8, Summary of Sample Results from Stream Section 3 Radionuclide No. of No. of Results > Average Maximum Enclosure I to letter dated October 29, 2008 10

Plum Brook Sediment Characterization Data Summary Samples MDA Concentration Concentration Analyzed (pCi/g) (pCi/g)

Cs-137 521 171 0.56 14.2 Co-60 521 1 0.2 0.2 Characterization of Plum Brook Country Club Ponds - Package SR-33 This characterization survey package was developed to investigate movement of cesium-bearing sediments from the Plum Brook into various areas of the Plum Brook Country Club (PBCC).

Three ponds are located on the Country Club grounds. The two larger ponds, located in the NW maintenance area, were formerly connected directly to the Plum Brook. They were modified to serve as a storage reservoir for the golf course watering system. The ponds were dredged and merged into a single pond and connected to the Plum Brook stream by gravity flow piping. A third, smaller pond which was not dredged, is located to the south of the main ponds. Dredge spoils were stored in two piles located to the west and north of the main ponds. All three ponds have been submerged by Plum Brook flood waters on multiple occasions including the large flooding events of 1968 and 1969, and most recently in March 2008. Soil from the dredge spoil piles has been gradually used over the past 10 to 15 years as fill on the golf course, mostly along the cart paths.

The survey included surface gamma scan surveys of the dredge spoil piles and the adjacent former storage pile footprint, scan survey along cart paths and on odd-numbered golf course holes (except No. 5) on the fairway side of the cart.path. Fairways were scanned between the 100 and 150 yard marker lines. Scan surveys were conducted using the Ludlum 2350-1 scaler with 2x2 in. Nal detector configured to count Cs-137 gammas. An action level of 300 gross cpm was established. Core samples were collected from the northern pond spoil piles and from south pond sediment.

All of the areas scanned except the former spoil pile footprint, located between the two present spoil piles, were below the scan action level. Two core sampling locations were established in the former spoil pile footprint, six on the two spoil piles and three in the south pond. A total of 41 core sub-samples were analyzed by gamma spectroscopy. The overall sample results are summarized in Table 9.

Table 9, Summary of PBCC Sample Results No. of No. of Results > Average Maximum Radionuclide Samples MDAConcentration Concentration Analyzed (pCi/g) (pCi/g)

Cs-137 41 29 1.4 8.5 Co-60 41 5 0.2 0.4 The highest concentration of Cs-137, 8.5 pCi/g, was measured in a surface sample (0 to 6 in.

depth) collected from the former spoil pile footprint. The second location sampled in the footprint yielded a concentration of 2.2 pCi/g, also in the 0 to 6 in. depth. Depth profiles for Cs-137 obtained from core samples collected from the spoil piles and the south pond are Enclosure I to letter dated October 29, 2008 I1I

Plum Brook Sediment Characterization Data Summary summarized in Table 10. Cobalt-60 was detected above MDA in 5 of the 41 samples - the average concentration was 0.2 pCi/g and the maximum was 0.4 pCi/g.

Enclosure I to letter dated October 29, 2008 12 Enclosure I to letter dated October 29, 2008 12 O

Plum Brook Sediment Characterization Data Summary Table 10, Cs-137 Depth Profiles from PBCC Samples (pCi/g)

Depth below Spoil Piles - six locations South Pond - three locations surface (in.) Average Maximum Average Maximum 0-6 1.9 7.5 1.1 1.1 6-18 1.7 4.7 1.7 2.8 18-30 1.5 3.3 NR NR 30-42 1.0 2.2 NR NR Table/ 0 Note:.

NR means no sample recovery Sample depths varied somewhatfrom the standarddepths shown for some of the samples.

3.5 Stream Section 4 - Stream Mouth and Wetlands Initial Survey of Plum Brook from US Rt. 6 to Sandusky Bay - Package SR-39 Sixty four locations were selected for collection of sediment samples from the stream section between US Rt. 6 and Sandusky Bay. The sampling design approach was to establish locations at regular intervals along the stream course. These included six transects to investigate the lateral distribution of sediments across the wetlands surrounding the stream. Sixty four sampling locations were selected. Sediment core samples were divided into sub-samples for the purpose of obtaining Cs-137 concentrations Vs depth. From these a total of 312 sub-samples were obtained for analysis including 20 QC split samples.

Of the 312 samples analyzed, 135 showed Cs-137 concentrations > MDA, with an average concentration for this stream section of 0.7 pCi/g (including MDA values). Three samples were>

10 pCi/g with a maximum of 20.6 pCi/g. Twenty five sample results for Cs-137 were > 2 pCi/g and 45 were > 1 pCi/g. Only four samples yielded Co-60 concentrations in excess of the MDA, with a maximum concentration of 0.3 pCi/g. Cesium-137 depth concentration profiles for the core sample locations yielding the four highest concentrations are shown in Table 11.

Enclosure I to letter dated October 29, 2008 13

Plum Brook Sediment Characterization Data Summary Table 11, SR-39 Depth Profiles for Cs-137 (pCi/g)

Depth (in.) Location SM6-6 SM1-4 SM1-2 SM9-4 0-6 20.0 3.4 1.2 1.2 6-18 1.3 11.7 1.7 5.9 18-30 3.1 4.1 2.2 2.2 30-42 0.7 2.9 3.0 2.4 42 - 54 <MDA 2.0 5.7 2.6 54-66 NR NR 7.7 NR 66-78 NR NR 1.0 NR Table 11 notes:

Location SM6-6; stream center - 75 yd. N. of Rt. 6.

Location SM1-4; stream center - lO yd. N. of Rt. 6.

Location SMI-2; seasonalpond-marsh west side of stream about 30 yd. N ofRt. 6.

Location SM9-4; stream center immediately N. of US Rt. 6.

NR means no recovery.

The resultfrom the 0 to 6 in. depth firom Location SM6-6 is reportedas 20.0 pCi/g, the averageof 20.6pCi/g and the QC split sample concentration of 19.3 pCi/g.

Investigation Surveys of Selected Areas along the Plum Brook from US Rt. 6 to Sandusky Bay -

Packages SR-44 and SR-53 Sediment core samples were collected from 57 locations under the Packages SR-44 and SR-53, established to investigate locations where the highest concentrations of Cs-137 were observed from samples collected under SR-39. A total of 309 samples were analyzed for Cs-137 and Co-60 (including 5 % QC split samples). Noting that these results are biased due to the sampling design approach, the average Cs-137 and Co-60 concentrations were 2.2 and 0.2 pCi/g respectively. No locations with Cs-137 or Co-60 concentrations greater than those measured in the SR-39 samples were observed. The greatest Cs-137 concentration was 16.8 pCi/g.

3.6 Sandusky Bay Characterization of Sandusky Bay Sediments - Package SR-34 Sediment samples were collected from 44 locations in the east end of Sandusky Bay between the Plum Brook Stream Mouth on the south and the Cedar Point Causeway on the north. The sampling locations were established on a judgment basis. Sediment cores were collected on a triangular grid laid out in a fan-shaped pattern radiating out from the stream mouth. This was to determine deposition patterns of Cs-bearing sediments transported from the stream into the Bay.

Cores were divided into depth increments for analysis. The depth increments were: 0 to 6, 6 to 18, 18 to 30, 30 to 48 and 48 to 60 inches. At many locations the sampler did not penetrate to the full 60 inches. A total of 138 core sub-samples were obtained for laboratory analysis.

The majority of the 138 samples yielded concentrations of Cs-137 and Co-60 that were less than their respective MDAs. Thirty seven showed positive results, with 33 > MDA for Cs-137, two >

Enclosure I to letter dated, October 29, 2008 14

Plum Brook Sediment Characterization Data Summary MDA for Co-60 and two > MDA for both. The highest concentration of Cs-137 was 3.9 pCi/g (in the 0 to 6 inch depth at location BY-37). The average Cs-137 concentration from all sample results, including MDA values, was 0.4 pCi/g. The maximum Co-60 concentration measured was 0.9 pCi/g and the average concentration in all samples was 0.25 pCi/g (with MDA values included).

3.7 PBRF Site Investigation Surveys Pentolite Ditch Subsurface - Package SR-43 This survey package was implemented to supplement the characterization of Pentolite Ditch sediments from previous surveys, specifically to examine depth profiles of Cs-137 and Co-60.

Eight locations were selected along the ditch bottom from the juncture of Pentolite Ditch and the Plum Brook proceeding in a westerly direction. A core was collected at each of the eight locations - six were located between the WEMS outfall and Plum Brook and two were located west of the WEMS outfall (in a portion of the Pentolite ditch not believed to have been previously sampled). The cores were divided into sub-samples by depths 0 to 6, 6 to 18 and proceeding in 12 inch increments to depth of refusal - typically at about 54 inches. The eight cores yielded a total of 35 samples for analysis by gamma spectroscopy plus an additional seven QC split samples. Twenty seven of the 42 samples showed Cs-137 concentrations above MDA and eight showed Co-60 concentrations > MDA. The highest activity core was from location PD-6 at the WEMS outfall. Cesium-137 and Co-60 concentrations Vs depth are shown in Table 12.

Table 12, WEMS Outfall Sediment Depth Profile Depth (in.) Cs-137 Co-60 (pCi/g) (pCi/g) 0-6 524 1.9 6-18 233 4.2 18-30 473 7.7 30-42 369 6.7 42-54 280 4.6 54-61 157 9.5 Tvo cores taken near the confluence with Plum Brook also yielded useful depth profile information. These profiles are shown in Table 13 Table 13, Sediment Depth Profiles for Eastern Pentolite Ditch Core PD-I Core PD-2 Depth (in.) Cs-137 Co-60 Cs-137 Co-60 (pCi/g) (pCi/g) (pCi/g) (pCi/g) 0-6 0.53 <MDA 1.1 <MDA 6-18 6.2 <MDA 12.8 <MDA 18-30 4.9 <MDA 13.6 <MDA 30-42 16.7 0.3 1.7 <MDA Enclosure I to letter dated October 29, 2008 15

4 Plum Brook Sediment Characterization Data Summary The two cores upstream from the WEMS outfall, PD-7 and PD-8 showed CS-137 concentrations

> MDA but all less than one pCi/g. All Co-60 results were < MDA (typical MDAs for Cs-137 and Co-60 are - 0.1 pCi/g).

Groundwater Wells on the PBRF- Package SR-35 Eighteen monitoring wells located on the Plum Brook site on in the vicinity of the PBRF were selected for collection of water and well-bottom sediment samples. It is noted that none of these wells have been maintained in recent years. Several are not capped and the well heads are near or slightly below grade surface.

Eight of the wells yielded sufficient sediment for gamma spectroscopy analysis. Additionally water samples were collected from the wells (some wells yielded only a dilute mixture of sediment and water). Sediment samples from three of the wells yielded detectable Cs-137 (concentrations > MDA). Sediment concentrations ranged from 0.3 to 1.3 pCi/g. The latter result was from a composite sample from a well located adjacent to the Plum Brook Reactor Building (this result was reported as a "qualitative" result, because the small sample volume did not match a standard calibration geometry). The Cs-137 measured in sediment from the wells likely originated from. contaminated surface soil adjacent to the wells as opposed to originating from contaminated sediment suspended in groundwater. None of the water samples analyzed showed concentrations > MDA. Eleven water samples were analyzed by a vendor laboratory for gamma emitters including Cs-137 and Co-60, Sr-90, Isotopic uranium and Am/Cm/Pu. All sample results reported by the vendor laboratory were < MDA.

Enclosure I to letter dated October 29, 2008 16

Plum Brook Sediment Characterization Data Summary - List of Survey Packages with Page Count Number of Pages Disc Number ID# Description SR-5 Plum Brook Section A Phase 1 43 1 SR-6 Plum Brook Section B Phase 1 46 1 SR-7 Ptum Brook Section C Phase- 1 51 1 SR-8 Ptum Brook Section D Phase 1 33 1 SR-9 Ptum Brook Section A Phase 2 61 1 SR-1O Plum Brook Section B Phase 2 56 1 SR-11 Plum Brook Section C Phase 2 70 1 SR-12 Plum Brook Section D Phase 2 42 1 SR-19 Plum Brook Section E Phase 1 44 1 SR-20 Plum Brook Section E Phase 2 54 1 SR-21 Waste Treatment Facitity 28 1 SR-22 Residential Yards Adjacent To Plum Brook 31 1 SR-33 Plum Brook - Ponds 62 1 SR-34 Plum Brook - Bay 176 1 SR-35 Plum Brook - Ground Water 122 1 SR-39 Plum Brook - Stream Mouth 134 1 SR-41 Plum Brook - Flood Plain 152 1 SR-43 Pentolite Ditch Sub Surface 40 1 SR-44 Plum Brook Investigational Sampling 63 1 SR-45 Bounding Of Plum Brook - Section A 71 2 SR-46 Bounding Of Plum Brook - Section B 34 2 SR-47 Bounding Of Ptum Brook - Section C 53 2 SR-48 Bounding Of Ptum Brook - Section D 32 2 SR-49 Bounding Of Plum Brook - Section E 33 2 SR-53 Plum Brook Stream Mouth Investigation 113 2 SR-54. Ptum Brook Floodplain 113 2 SR-95 Waste Water Treatment Facility 71 2 SVI-04 Plum Brook Creek Bed Scoping Survey 593 3 TOTAL PAGES 2421 October 29, dated October 2008 17 Enclosure II to letter dated to letter 29, 2008 17

Plum Brook Sediment Characterization Data Summary - List of Procedures Procedure Title Revision Number Number CS-01 Survey Methodology to Support License Termination 2 CS502 FSS Area Isolation and Control 4 CS-03 Sample Chain of Custody Controls 0 CS-04 Laboratory Sample Preparation 1 CS-05' Final Status Survey Area Classification 0 CS-06 Survey Unit Inspection to Support FSS Design Issue, Control and Accountability of FSS/Characterization CS-07 Portable Radiological Instrumentation 1

CS-08 Final Status Survey Design 1

CS-09 Final Status Survey Data Quality Assessment CS-Oil Operation of the Ludlum Model 2350-1 Data Logger Survey Instrument CS-012 Documentation of FSS/Characterization Surveys 0 RP-005 Radiological Surveys 0 RP-021 Operation and Calibration of the ORTEC Gamma 1 Spectroscopy System RP-035 Laboratory Balances RP-60 PBRF Radiological Laboratory Quality Assurance/Quality 0 Control Program RP-O7 Radiation Protection and FSS/Characterization Training 1 Program Note: The procedure CS-O1 superseded RP-600, "PBRF Verification Survey Program" in late 2005.

Enclosure I to letter dated October 29, 2008 18 Enclosure I to letter dated October 29, 2008 18