Text

Rev 2 to Calculation E900-05-032, Open Land FSS Design - OL3 Paved Surfaces & Concrete, Appendices a - B to Final Status Survey Report for Saxton Nuclear Experimental Corporation 0L3 Paved Surfaces and Concrete.
	ML052140106
Person / Time
Site:	Saxton File:GPU Nuclear icon.png
Issue date:	06/09/2005
From:	Tritch T; FirstEnergy Corp
To:	; Office of Nuclear Reactor Regulation
References
	E900-05-032, Rev 2
	Download: ML052140106 (65)
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APPENDIX A SNEC Calculation E900-05-032 Open Land FSS Design - OL3 Paved Surfaces and Concrete

Original A d. SNEC CALCULATION COVER SHEET CALCULATION DESCRIPTION Calculation Number Revision Number Effective Date Page Number E900-05-032 2 I IP of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Question 1 - Is this calculation defined as 'In QA Scope'? Refer to definition 3.5. Yes 0 No ]

Question 2 - Is this calculation defined as a 'Design Calculation'? Refer to definitions 3.2 and 3.3. Yes El No a NOTES: If a 'Yes' answer is obtained for Question 1, the calculation must meet the requirements of the SNEC Facility Decommissioning Quality Assurance Plan. If a 'Yes' answer is obtained for Question 2, the Calculation Originator's immediate supervisor should not review the calculation as the Technical Reviewer.

DESCRIPTION OF REVISION Revision I - add notation to Table 2 for both the Ludlum 43-37 and 43-68B probes

- renumber section 2.0

- correct three grid scanning designations on Attachment 6-4 Revision 2 - update Table 2 with the correct DCGLw Action Level values from Attachments 4-1, 4-2, and 4-3 APPROVAL SIGNATURES Calculation Originator Tristan M. Tritch/ , 4 1 I Date Technical Reviewer W. J. Coopern Date Additional Review A. Paynter! \ I N b\ Date 4q -g Additional Review

Wa _

N C'.GALC U 0 N SHEET Cakculation Number Revision Number Page Number E900-05-032 2 Page 2 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 1.0 PURPOSE 1.1 The purpose of this calculation is to develop a final status survey design for open land area OL3 (non-soil only) at the Saxton Nuclear Experimental Corporation (SNEC) facility. The soil portions of OL3 will be surveyed under Open Land FSS Design - OL3, E900-05-024.

The OL3 fence surveys will be performed under Miscellaneous Chain Link Fences - Survey Design, E900-05-023.

1.2 Survey Area OL3 is an Impacted Class 1 area which encompasses the old on-site driveway, the current parking area, and the soil processing facility (SPF, also known as dirt world) on the SNEC facility decommissioning project. It covers approximately 9,400 square meters (94 10m x 10m grids). Of that surface area, slightly more than 8180 square meters is soil, 991 square meters is concrete, and 225 square meters is asphalt. Table 5-5 of the SNEC License Termination Plan (LTP) limits the physical size of Class 1 survey areas to 2000 square meters. Due to this area constraint, OL3 will be subdivided into six smaller survey units, namely 0L3-1 through OL3-6, containing 2000, 1800, 1800, 1300, 2000, and 500 square meters, respectively. The corresponding soil areas are 2000, 654, 1800, 1294, 1972, and 464 square meters. Of those areas, only the concrete and asphalt in OL3-2, and OL3-4 through 0L3-6 are involved in this survey design.

1.3 The LTP lists SSGS concrete as Class 3 and asphalt roadway as Class 2 structures. OL3-2 contains 921 square meters of concrete and 225 square meters of asphalt. 0L3-4, OL3-5 and OL3-6 contain 6, 28, and 36 square meters of concrete, respectively. Class 2 structures are limited to 1000 square meters and Class 3 structures are limited to 10,000 square meters, so the four survey units in OL3 are broken down further. OL3-2 concrete (921 square meters) is now MA8-22 and OL3-2 asphalt (225 square meters) is now MA8-

23. The concrete in OL3-4, 0L3-5, and 0L3-6 (70 square meters) is being given the designation MA8-24.

1.4 The general layout of the survey units is shown on Attachment 1-1. Scale survey drawings of the concrete and asphalt areas are shown on Attachments 6-1, 6-3, and 6-5.

2.0

SUMMARY

OF RESULTS The following information should be used to develop a survey request for this survey unit. The effective DCGLw value is listed below. This value is derived from previously approved derived values for "CV Yard Soil and Boulder Samples' in SNEC calculation E900-04-005 (Reference 3.13).

The US NRC has reviewed and concurred with the methodology used to derive these values. See Attachments 2-1 through 2-3 and Reference 3.8.

Table 1, DCGLw Values I Gross Activity DCGLw (dpm/1r0 cm'r 26445 (19834 A.L.)

NOTE: AL Isthe site Administrative Lmit (75% of effective DCGLw) 2.1 Survey Design 2.1.1 Scanning of both concrete and asphalt surfaces shall be performed using a L2350 with 43-68B large area gas flow proportional counter or a 43-37 extra large' probe calibrated to Cs-137 (see typical calibration information on Attachments 3-1 and 3-2). Generic approval fo ruse of the 43-37 probe is included in Reference 3.15.

~ ~2:TSNEC~CALCULAON SHEET ~'-.

Calculation Number Revision Number Page Number E900-05-032 2 Page 3 of 11 Subject Open Land FSS Design - 0L3 Paved Surfaces and Concrete 2.1.2 The instrument efficiency shall not be less than that assumed on Attachment 4-1 as 23.9% - Cs-137 for the 43-68B probe or less than 20.0% - Cs-137 for the 43-37 probe in its lowest efficiency region assumed on Attachment 4-3.

2.1.3 For concrete and asphalt surfaces, an efficiency correction factor (ECF) is applied to compensate for efficiency loss when surveying rough surfaces based on Reference 3.14 and Attachment 24. The ECF, using the 43-68B probe is based on a surface irregularity of 3 inches or less. This is conservative as actual observed irregularity is typically less than one inch; however, some rather large deviations exist due to the operation of large earthmoving equipment in the vicinity. Also, the loss of efficiency is based on moving the detector away from a 150 cm2 source. If the area of the residual activity is larger, then the efficiency loss would be smaller due to an increase in the detector's "field-of-view".

2.1.4 Using the 43-37 probe, an efficiency correction factor (ECF) is applied to compensate for efficiency loss when surveying rough surfaces based on Reference 3.15 and Attachment 2-5. The ECF, using the 43-37 probe is based on a surface irregularity of 1 inch or less. This is conservative based on using the 43-37 probe on relatively smooth surfaces.

2.1.5 The fraction of detectable beta-emitting activity affects the efficiency and is determined by the nuclide mix. The mix detectable beta fraction is determined to be 60% based on Reference 3.13. Because the adjusted DCGLw used is based only on the modified Cs-137 DCGLw, the mix percentage is not applied to the adjusted surrogate DCGLw. The gross activity DCGLw, which would include all the low energy activity and would require an adjustment to the mix percentage, is considerable higher at 44434 dpm 100cm2 . The Cs-137 adjusted surrogate activity already accounts for the detectable beta yield of the mix.

Table 2, Surface Scanning Parameters Prob e MDCscan Scan Speed Maximum Distance from DCGLw Action % Coverage (dprnh00cm2)' (cmlsec) Surface Level 43-688 5077 concrete > 190 ncpm Up to l0%

10 3' (gap between detector 43-68B 4405 asphalt face & surface) > 1190 ncpm 10% - 100%

43-37 7884 concrete 30.5 I (gap between detector > 2260 ncpm Up to 100%

78onretep30.5 face & surface)

^See Attachment 2-1, 2-2 4-1, 42, and 4-3 for calculations 2.1.6 This MDCscan for concrete (shown in Attachment 4-1) is based on a 360 cpm background. On 317/05, measurements were collected from the SSGS boiler pad in OL1. This data is used for the variability assessment for the COMPASS determination of sample requirements and is shown in Attachment 8-2. Unaffected material backgrounds were determined using data obtained from the Williamsburg Station which resulted in a mean background value of 306 +/- 34.5 cpm as shown in Attachment 8-1.

SNC CALCULATON LATiX SHEET " * . aretr-A Calculation Number Revision Number Page Number E900-05-032 2 Page 4 of 11 Subjed Open Land FSS Design - OL3 Paved Surfaces and Concrete 2.1.7 The MDCscan for asphalt (shown in Attachment 4-2) is based on a 271 cpm background. On 3/7105, measurements were collected from the SSGS parking lot asphalt in OL1. This data is used for the variability assessment for the COMPASS determination of sample requirements and is shown in Attachment 8-3.

2.1.8 The MDCscan using the 43-37 probe (shown in Attachment 4-3) is based on a 1020 cpm background. On 5112/05, measurements were collected on three different surfaces in OLI: the DSB pad, asphalt, and the SSGS boiler pad. This data is shown on Attachment 8-4.

2.1.8.1 The efficiency is determined with the same source as used for the 43-68B and the effective area of the detector is assumed to be 100 cm2 for determining the MDCscan. This will underestimate the response of the detector to larger sources but produce similar efficiencies and MDCs as for the 43-688.

2.1.8.2Scanning using the 43-37 probe will be done either on flat surfaces with surface irregularities typical of poured concrete or rolled macadam pavement.

Uneven surfaces or edges will be scanned with the 43-68B.

2.1.8.3 Because the 43-37 has a much larger effective surface than the 43-68B and the MDC and action level are based on a 100 cm2 elevated spot, the 43-37 may provide action level count rates on larger diffuse source areas that actually are less than the DCGL. Therefore, the 43-37 will be used to screen surfaces and will be considered to be the official results only if no action levels are observed.

2.1.8.4 Any action level observed with the 43-37 will be rescanned with the 43-68B. If no AP is observed with the 43-68B, then there is no AP. APs observed in followup scans using the 43-68B will be handled and documented in the SR per section 2.1.10 below.

2.1.8.5 The fraction scanned with the 43-37 and results should be separately reported in the SR for each survey unit/grid in a similar manner as used for the 43-688 (e.g., 90% scanned with 43-37, one alarm rescanned with 43-68B, no 43-686 AP).

2.1.9 The scan DCGLw Action Levels listed in Table 2 do not include background. The DCGLw action level is based on fixed measurements and does not include 'human performance factors' or 'index of sensitivity' factors (see Reference 3.10).

2.1.10 If a net count rate greater than the *DCGLw action level" in Table 2 is encountered during the scanning process, then the surveyor should stop and locate the boundary of the elevated area, and then perform a 'second phase" fixed point count of at least 30 seconds duration. If the second phase result equals or exceeds the ODCGLw action level" noted in Table 2, then the surveyor should mark the elevated area appropriately and document the count rate observed and an estimate of the affected area.

2.1.10.1 Class 3 concrete should be scanned up to 10% surface coverage at a rate of about 10 cm per second using the 43-686 probe or 30.5 cm per second using the 43-37 probe. Areas that cannot be accessed should be clearly noted along with the reason for not completing the scan in that area.

Calculation Nun iber Revision Number Page Number E900-05-03: 2 2 Page5of11 Subject Open Landi FSS Design - OL3 Paved Surfaces and Concrete Alternate areas should be selected from the remainder to provide the required coverage.

2.1.10.2 Class 2 asphalt should be scanned 10% to 100% surface coverage at a rate of about 10 cm per second using the 43-68B probe or 30.5 cm per second using the 43-37 probe. Areas that cannot be accessed should be clearly noted along with the reason for not completing the scan in that area.

Alternate areas should be selected from the remainder to provide the required coverage.

2.1.10.3 The surfaces of both the concrete and asphalt should be clear of debris to ensure detection parameters are not affected.

2.1.11 The minimum number of fixed measurement sampling points indicated by the COMPASS computer program (Reference 3.3) is 11 each for both the concrete and asphalt in OL3-2 and the total of all concrete surfaces in OL3-4 through OL3-6 (see COMPASS output on Attachments 7-1 to 7-5). Fixed point measurements should be lAW Section 2.2. The MDCscan (concrete) using the 43-68b is below the effective administrative DCGLwc137 (5077 DPMI OOcm 2 MDCscan @360 cpm bkg <

19834 DPM/100cm 2 AL). The MDCscan (asphalt) is below the effective administrative DCGLwc, .137 (4405 DPMW100cm 2 MDCscan @271 cpm bkg < 19834 DPMI1 00cm2 AL). The MDCscan using the 43-37 probe is below the effective administrative DCGLwc, 1 37 (7884 DPMI 00cm 2 MDCscan @1020 cpm bkg < 19834 DPMI1 00cm 2 AL) 2.1.12 All of the concrete in OL3-4 through OL3-6 is considered to be one surface with respect to obtaining static measurements because there is only 70 square meters of material and it is all of the same vintage.

2.1.13 VSP (Reference 3.4) is used to plot all random start concrete and asphalt sampling points on the included diagrams. See Attachments 6-1, 6-3, and 6-5 for VSP sampling point locations).

2.1.14 Some sampling points may need to be adjusted to accommodate obstructions within the survey area. Contact the SR coordinator to report any difficulties encountered when laying out grid sampling points.

2.1.15 Because of the unusual arrangement of the multiple concrete surfaces in OL3, the drawings in Attachment 6 are intended to be as close as practicable to the as-left conditions. If the actual layout is different from that shown, then review with the cognizant SR coordinator, finish the survey if practicable, and mark up the drawings to indicate actual layout.

2.1.16 When an obstruction is encountered that will not allow collection of a sample, contact the cognizant SR coordinator for permission to either move or delete the sampling point.

SNEC CALCULATION SHEET '-.-,-'

Calculation Number Revision Number Page Number E900-05-032 2 Page 6 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete

' NOTE If remediation actions are taken as a result of this survey, this survey design must be revised or re-written entirely.

2.2 Measure both fixed point and elevated areas(s) on concrete and asphalt IAW SNEC procedure E900-IMP-4520.04 (Reference 3.2).

3.0 REFERENCES

3.1 SNEC Calculation No. E900-03-018, "Optimize Window and Threshold Settings for the Detection of Cs-1 37 Using the Ludlum 2350-1 and a 44/10 Nal Detector", 817/03.

3.2 SNEC Procedure E900-IMP-4520.04, 'Survey Methodology to Support SNEC License Termination'.

3.3 COMPASS Computer Program, Version 1.0.0, Oak Ridge Institute for Science and Education.

3.5 SNEC Facility License Termination Plan.

3.6 SNEC Procedure E900-IMP-4500.59, "Final Site Survey Planning and DQA'.

3.7 GPU Nuclear, SNEC Facility, uSite Area Grid Map", SNECRM-020, Sheet 1, Rev 4, 1/18/05.

3.8 SNEC Calculation E900-03-012, Effective DCGL Worksheet Verification.

3.9 SNEC Procedure E900-IMP-4520.06, 'Survey Unit Inspection in Support of FSS Design".

3.10 NUREG-1575, "Multi-Agency Radiation Survey and Site Investigation Manual', August, 2000.

3.11 Microsoft Office Excel, Version 11.0.5612, Microsoft Corporation Inc., 1985-2003.

3.12 SNEC Procedure E900-ADM-4500.39 'Chain of Custody for Samples" 3.13 CV Yard Survey Design - North West Side of CV, E900-04-005.

3.14 SNEC Calculation 6900-02-028, GFPC Instrument Efficiency Loss Study.

3.15 SNEC Calculation E900-05-031, Use of the 43-37 Detector and Ludlum 239 Floor Monitor for FSS Surveys 3.16 SNEC Survey 43-37 GFPC Measurements OL1, 5/12105.

3.17 1994 Saxton Soil Remediation Project Report, May 11, 1995.

4.0 ASSUMPTIONS AND BASIC DATA 4.1 The COMPASS computer program is used to calculate the required number of random start systematic samples to be taken in the survey unit (Reference 3.3).

4.2 Data shown on Attachments 8-2 and 8-3 are used as the initial estimates of variability for concrete and asphalt, respectively.

4.3 The MARSSIM Sign Test will be applicable for this survey design. No background subtraction will be performed under this criterion during the DQA phase.

SNEC CALCULATIONSHEET .

Calculation Number Revision Number Page Number E900-05-032 2 Page 7 of 11 Subject Open Land FSS Design - 0L3 Paved Surfaces and Concrete 4.4 The Visual Sample Plan (VSP) computer code (Reference 3.4) locates the required number of fixed survey points, determined by COMPASS, on the survey maps for asphalt in each survey unit. Fixed survey points for concrete were chosen independent of VSP.

4.5 References 3.5 and 3.6 were used as guidance during the survey design development phase.

4.6 Background reference for concrete was obtained from the Williamsburg concrete study and is 306 crm (Attachment 8-1). Asphalt background was determined to be approximately 271 com (Attachment 8-3). Background using the 43-37 probe was estimated to be 1020 cpm (Reference 3.16 and Attachment 8-4).

4.7 The determination of the physical extent of this area is based on Reference 3.7. The extent of the SSGS footprint was later modified/extended from OL3 into OL7-1 by virtue of a site walkdown on 4/28/05.

4.8 OL3 has been subjected to extensive remediation.

4.8.1 Contamination was detected in the "bum area" in 0L3-4 and southern portion of 0L3-5. Soil was removed, the area was rescanned and additional soil samples were taken.

4.8.2 Soil from the northernmost portion of 0L3-5 was removed. See Figures 1 and 3 of the 1994 Saxton Soil Remediation Project Report (Reference 3.17). Soil activity as high as 38 pCilg was removed from this area. Grids were not designated the way they are in 2005, but one can get an idea of the area remediated when referencing to the location of the Penelec Line Shack.

4.8.3 One grid adjacent to the former SSGS cooling water intake, in 0L3-6, was subject to recent remediation when activity was found during an FSS survey of 0L9-2. The highest activity found was 14.4 pCilg. Sampling, following removal of approximately 18 inches of soil, produced no activity greater than the DCGL.

4.9 This survey design uses Cs-137 as a surrogate for all SNEC facility related radionuclides in the survey unit. The effective DCGLw is the Cs-137 DCGLw from the SNEC LTP (28,000 dpm/100 cm2 ) adjusted (lowered) to compensate for the presence (or potential presence) of other SNEC-related radionuclides. In addition, an administrative limit (75%) has been set that further lowers the permissible Cs-137 concentration to an effective surrogate DCGLw for this survey area.

4.10 The sample database contained only one sample, which was assayed both on site and off site, with which to determine the effective radionuclide mix for Area OL3. In order to obtain a more representative mix of expected radionuclides, data from OLI and OL2 were used instead. The decayed set of sample results were input to the spreadsheet titled 'Effective DCGL Calculator for Cs-1 37" (Reference 3.8) to determine the effective DCGLw values for the survey units, then changed to an equivalent surface contamination level. The output of this spreadsheet is shown on Attachment 2-1 which is copied from Reference 3.13. The spreadsheet was previously reviewed.

The 43-68B detector scan MDC calculation is determined based on a 10 cmlsec scan rate, a 1.38 index of sensitivity (95% correct detection probability and 60% false positive) and a detector sensitivity of 23.9% for Cs-137. The 43-37 detector scan MDC calculation is determined based on a 30.5 cm/sec scan rate, a 1.38 index of sensitivity (95% correct detection probability and 60% false positive) and a detector sensitivity of 20.0% for Cs-137.

~ ~,SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 2 Page 8 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Additionally, the detection system incorporates a Cs-137 window that lowers sensitivity to background in the survey unit. Using the 43-68B probe, the concrete background is approximately 360 cpm and the asphalt background is approximately 271 cpm in 0L3-2.

Using the 43-37 probe, background is approximately 1020 cpm.

4.11 The survey units described in this survey design were inspected. A copy of the OL3 specific portion of the SNEC facility post-remediation inspection report (Reference 3.9) is included as Attachment 9-1.

4.12 No special area characteristics including any additional residual radioactivity (not previously noted during characterization) have been identified in this survey area.

4.13 The decision error for this survey design is 0.05 for the cc value and 0.1 for the pvalue.

4.14 "Special measurements", as described in the SNEC LTP sec 5.5.3.4, are not included in this survey design.

4.15 No additional sampling will be performed lAW this survey design beyond that described herein.

4.16 SNEC site radionuclides and their individual DCGLw values are listed on Exhibit I of this calculation.

4.17 The survey design checklist is listed in Exhibit 2.

4.18 Area factors are shown as part of COMPASS output (see Attachment 7-1) and are based on the Cs-137 area factors from the SNEC LTP.

5.0 CALCULATIONS 5.1 All calculations are performed internal to applicable computer codes or within an Excel spreadsheet.

6.0 APPENDICES 6.1 Attachment 1-1 is a diagram of survey units OL3.

6.2 Attachments 2-1 and 2-5 show the DCGL Calculation Logic - CV Yard Soil & Boulders and the Cs-137 Efficiency Loss with Distance from Source study for GFPC probes (Reference 3.13 and 3.14).

6.3 Attachments 3-1 and 3-2 are copies of the calibration data from typical Nal and GFPC radiation detection instrumentation that will be used in this survey area.

6.4 Attachments 4-1 through 4-3 are the MDCscan calculation sheets for concrete and asphalt surface materials in dpm/100 cm2 using the 43-68B and the MDCscan calculation using the 43-37 probe.

6.5 Attachment 5-1 is the breakdown of concrete and asphalt into miscellaneous survey units.

6.6 Attachments 6-1 through 6-6 show the random sampling points and scan locations, for both concrete and asphalt, and reference coordinates for Survey Units 0L3-2 (MA8-22 and MA8-23) and 0L3-4 through 0L3-6 (MA8-24).

6.7 Attachments 7-1 through 7-5 are COMPASS outputs for Survey Units MA8-22 through MAB-24 showing area factors, the number of sampling points in each survey unit, and prospective power.

Calculation Number Reviion Number Page Number E900-05-032 2 Page 9 of 11 Subjed Open Land FSS Design - OL3 Paved Surfaces and Concrete 6.8 Attachments 8-1 through 8-4 show both concrete and asphalt backgrounds and material variability results from the Williamsburg concrete and OL1 concrete and asphalt samples.

The background established for the 43-37 probe is also shown.

6.9 Attachment 9-1 is copied from the most recent inspection report for 0L3.

Calculation Number Revision Number Page Number E900-05032 2 Page 10 of 11 Subject Open Land FSS Design - 0L3 Paved Surfaces and Concrete V

Exhibit I SNEC Facility Individual Radionuclide DCGL Values (a) 25 mrem/y Limit 4 mremly Goal 25 mremly Limit (All Pathways) (Drinking Water)

Radionuclide Surface Area Open Land Areas Open Land Areas (

(dpml100cm2 ) (Surface & Subsurface) (Surface & Subsurface)

(pCUg) (pCUg)

Am-241 2.7E+01 9.9 2.3 C-14 3.7E+06 2 5.4 Co-60 7.1 E+03 3.5 67 Cs-137 2.8E+04 6.6 397 Eu-152 1.3E+04 10.1 1440 H-3 1.2E+08 132 31.1 Ni-63 1.8E+06 747 1.9E+04 Pu-238 3.0E+01 1.8 0.41 Pu-239 2.8E+01 1.6 0.37 Pu-241 8.8E+02 86 19.8 Sr-90 8.7E+03 1.2 0.61 NOTES:

(a) While drinking water DCGLs will be used by SNEC to meet the drinking water 4 mrem/y goal, only the DCGL values that constitute the 25 mremly regulatory limit will be controlled under this LTP and the NRC's approving license amendment.

(b) Usted values are from the subsurface model. These values are the most conservative values between the two models (i.e.,

surface & subsurface).

~ ~ SNEC-CALCULATION

,t*- HE',-

Calculation Number Revision Number Page Number E900-05-032 2 Page 11 of 11 Subject Open Land FSS Design - 0L3 Paved Surfaces and Concrete Exhibit 2 Survey Design Checklist Calculation No. Location Codes E900-05-032, Rev. 2 0L3 REVIEW FOCUS Status Reviewer I1TEM (Circle One) Initials& Date Has a survey design calculation number been assigned and is a survey design summary Yes gA description provided?

2 Are drawings/diagrams adequate for the subject area (drawings should have compass Yes, 2r r w n s d a r m d q a e f r headin gs )? __ _ _ _ _ _ _ _ _ _ _

3 Are boundaries property identified and is the survey area classification clearly indicated? Yes, _

4 Has the survey area(s) been properly dividedInto survey units LAW EXHIBIT 10 Yes, )

5 Are physical characteristics of the areallocation or system documented? Yes, _

6 Is a remediation effectiveness discussion included? Yes, 7 Have characterization survey and/or sampling results been converted to units that are Yes, comparable to applicable DCGL values?

8 1s survey and/or sampling data that was used for determining survey unit variance included? Yes, )

9 Is a description of the background reference areas (or materials) and their survey and/or

_ sampling results included along with ajustification for their selection? es,< >

10 Are applicable survey and/or sampling data that was used to determine variability included? Yes, (9)

II Will the condition of the survey area have an impact on the survey design, and has the Yes, probable impact been considered in the design? Yes,__

Has any special area characteristic including any additional residual radioactivity (not 12 previously noted during characterization) been identified along with its impact on survey Yes design?

13 Are all necessary supporting calculations and/or site procedures referenced or included?s N/A 14 Has an effective DCGLw been identified for the survey unit(s)? , N/A .

15 Was the appropriate DCGLuc included in the survey design calculation? Yes, 16 Has the statistical tests that will be used to evaluate the data been identified? Yes, 17 Has an elevated measurement comparison been performed (Class I Area)? Yes, 4l 18 Has the decision error levels been identified and are the necessary justifications provided? Yes, &

19 Has scan Instrumentation been Identified along with the assigned scanning methodology? (?e N/A 20 Has the scan rate been identified, and Is the MDCscan adequate for the survey design? NMA /;4 .

21 Are special measurements e.g., In-situ gamma-ray spectroscopy required under this design, Yes <

and is the survey methodology, and evaluation methods described? .

22 Is survey instrumentation calibration data included and are detection sensitivities adequate? Yes, v 23 Have the assigned sample and/or measurement locations been dearly identified on a diagram Yes, or CAD drawing of the survey area(s) along with their coordinates? es,_boy 24 Are investigation levels and administrative limits adequate, and are any associated actions N/A

_ _ _cearly indicated? ( V 1 '

25 For sample analysis, have the required MDA values been determined.? Yes, _

26 Has any special sampling methodology been Identified other than provided In Reference 6.3? Yes, 1 NOTE: a copy of this completed form or equivalent, shall be induded within the survey design calculation.

- r- ; ..-.'

% .U _ ; ___ A-SNEC CALCULATION COVER SHEET CALCULATION DESCRIPTION Calculation Number Revision Number Effective Date Page Number E900-05-032 1 L Osl I of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Question I - Is this calculation defined as 'In QA Scope'? Refer to definition 3.5. Yes El No El Question 2 - Is this calculation defined as a 'Design Calculation"? Refer to definitions 3.2 and 3.3. Yes 0E No El NOTES: If a Yes answer is obtained for Question 1, the calculation must meet the requirements of the SNEC Facility Decommissioning Quality Assurance Plan. If a 'Yes' answer is obtained for Question 2, the Calculation Originator's immediate supervisor should not review the calculation as the Technical Reviewer.

DESCRIPTION OF REVISION Revision 1 - add notation to Table 2 for both the Ludlum 43-37 and 43-68B probes

- renumber section 2.0

- correct three grid scanning designations on Attachment 6-4 APPROVAL SIGNATURES Calculation Originator Tristan M. Tritchl LA , ;> n ok ) Date /0 !5 Technical Reviewer W. J. Cooperl ; Date Additional Review A. Paynterl Date 6 A e I Additional Review Date

`3-:1 c CA!XIJILATION:SEE Calculation Number Revision Number Page Number E900-05-032 I Page 2 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 1.0 PURPOSE T 1.1 The purpose of this calculation is to develop a final status survey design for open land area OL3 (non-soil only) at the Saxton Nuclear Experimental Corporation (SNEC) facility. The soil portions of OL3 will be surveyed under Open Land FSS Design - OL3, E900-05-024.

The OL3 fence surveys will be performed under Miscellaneous Chain Link Fences - Survey Design, E900-05-023.

1.2 Survey Area OL3 is an Impacted Class 1 area which encompasses the old on-site driveway, the current parking area, and the soil processing facility (SPF, also known as dirt world) on the SNEC facility decommissioning project. It covers approximately 9,400 square meters (94 1Om x 1Om grids). Of that surface area, slightly more than 8180 square meters is soil, 991 square meters is concrete, and 225 square meters is asphalt. Table 5-5 of the SNEC License Termination Plan (LTP) limits the physical size of Class 1 survey areas to 2000 square meters. Due to this area constraint, OL3 will be subdivided into six smaller survey units, namely OL3-1 through OL3-6, containing 2000, 1800, 1800, 1300, 2000, and 500 square meters, respectively. The corresponding soil areas are 2000, 654, 1800, 1294, 1972, and 464 square meters. Of those areas, only the concrete and asphalt in OL3-2, and OL3-4 through OL3-6 are involved in this survey design.

1.3 The LTP lists SSGS concrete as Class 3 and asphalt roadway as Class 2 structures. OL3-2 contains 921 square meters of concrete and 225 square meters of asphalt. OL3-4, OL3-5 and OL3-6 contain 6, 28, and 36 square meters of concrete, respectively. Class 2 structures are limited to 1000 square meters and Class 3 structures are limited to 10,000 square meters, so the four survey units in OL3 are broken down further. OL3-2 concrete (921 square meters) is now MA8-22 and OL3-2 asphalt (225 square meters) is now MA8-

23. The concrete in OL3-4, OL3-5, and OL3-6 (70 square meters) is being given the designation MA8-24.

1.4 The general layout of the survey units is shown on Attachment 1-1. Scale survey drawings of the concrete and asphalt areas are shown on Attachments 6-1, 6-3, and 6-5.

2.0

SUMMARY

OF RESULTS The following information should be used to develop a survey request for this survey unit. The effective DCGLw value is listed below. This value is derived from previously approved derived values for 'CV Yard Soil and Boulder Samples' in SNEC calculation E900-04-005 (Reference 3.13).

The US NRC has reviewed and concurred with the methodology used to derive these values. See Attachments 2-1 through 2-3 and Reference 3.8.

Table 1, DCGLw Values I Gross Actvity DCGLw (dprn100 cm) 26445 (19834 A.L.)

NOTE: AL is the site Administrative Limit (75% of effetive DCGLw) 2.1 Survey Design 2.1.1 Scanning of both concrete and asphalt surfaces shall be performed using a L2350 with 43-68B large area gas flow proportional counter or a 43-37 'extra large' probe calibrated to Cs-137 (see typical calibration information on Attachments 3-1 and 3-2). Generic approval fo ruse of the 43-37 probe is included in Reference 3.15.

~.,~ - :SNEC CALCULATION SHEET K Calculation Number Revision Number Page Number E900-05-032 I Page 3 of 11 Subject Open Land FSS Design - 01-3 Paved Surfaces and Concrete 2.1.2 The instrument efficiency shall not be less than that assumed on Attachment 4-1 as 23.9% - Cs-137 for the 43-68B probe or less than 20.0% - Cs-137 for the 43-37 probe in its lowest efficiency region assumed on Attachment 4-3.

2.1.3 For concrete and asphalt surfaces, an efficiency correction factor (ECF) is applied to compensate for efficiency loss when surveying rough surfaces based on Reference 3.14 and Attachment 2-4. The ECF, using the 43-68B probe is based on a surface irregularity of 3 inches or less. This is conservative as actual observed irregularity is typically less than one inch; however, some rather large deviations exist due to the operation of large earthmoving equipment in the vicinity. Also, the loss of efficiency is based on moving the detector away from a -150-cm2 -source--If-the-area-of-the--- --

residual activity is larger, then the efficiency loss would be smaller due to an increase in the detector's "field-of-view".

2.1.4 Using the 43-37 probe, an efficiency correction factor (ECF) is applied to compensate for efficiency loss when surveying rough surfaces based on Reference 3.15 and Attachment 2-5. The ECF, using the 43-37 probe is based on a surface irregularity of 1 inch or less. This is conservative based on using the 43-37 probe on relatively smooth surfaces.

2.1.5 The fraction of detectable beta-emitting activity affects the efficiency and is determined by the nuclide mix. The mix detectable beta fraction is determined to be 60% based on Reference 3.13. Because the adjusted DCGLw used is based only on the modified Cs-137 DCGLw, the mix percentage is not applied to the adjusted surrogate DCGLw. The gross activity DCGLw, which would include all the low energy activity and would require an adjustment to the mix percentage, is considerable higher at 44434 dpm 100cm 2 . The Cs-137 adjusted surrogate activity already accounts for the detectable beta yield of the mix.

Table 2, Surface Scanning Parameters Prob e MDCscan Scan Speed Maximum Distance from DCGLw Action % Coverage (dpmJ1 00Cm 2), (cmlsec) Surface Level 43-68B 5077 concrete > 200 ncpm Up to 10%

10 3- (gap between detector 43-688 4405 asphalt face & surface) > 180 ncpm 10% - 100%

43-37 7884 concrete 30.5 1- (gap between detector > 630 ncpm Up to 100%

or asphalt face & surface)

See Attachment 2-1, 2-2,4-1,4-2, and 4-3 for calculations 2.1.6 This MDCscan for concrete (shown in Attachment 4-1) is based on a 360 cpm background. On 3/7/05, measurements were collected from the SSGS boiler pad in OL1. This data is used for the variability assessment for the COMPASS determination of sample requirements and is shown in Attachment 8-2. Unaffected material backgrounds were determined using data obtained from the Williamsburg Station which resulted in a mean background value of 306 +/- 34.5 cpm as shown in Attachment 8-1.

~~~SNEC CALCULATION SHEET t Calculation Number Revsion Number Page Number E900-05-032 Page 4 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 2.1.7 The MDCsc3n for asphalt (shown in Attachment 4-2) is based on a 271 cpm background. On 317105, measurements were collected from the SSGS parking lot asphalt in OL1. This data is used for the variability assessment for the COMPASS determination of sample requirements and is shown in Attachment 8-3.

2.1.8 The MDCscan using the 43-37 probe (shown in Attachment 4-3) is based on a 1020 cpm background. On 5/12/05, measurements were collected on three different surfaces in OL1: the DSB pad, asphalt, and the SSGS boiler pad. This data is shown on Attachment 8-4.

2.1.8.1 The efficiency is determined with the same source as used for the 43-68B and the effective area of the detector is assumed to be 100 cm2 for-de-trhining the MDCscan. This will underestimate the response of the detector to larger sources but produce similar efficiencies and MDCs as for the 43-68B.

2.1.8.2 Scanning using the 43-37 probe will be done either on flat surfaces with surface irregularities typical of poured concrete or rolled macadam pavement.

Uneven surfaces or edges will be scanned with the 43-68B.

2.1.8.3 Because the 43-37 has a much larger effective surface than the 43-68B and the MDC and action level are based on a 100 cm 2 elevated spot, the 43-37 may provide action level count rates on larger diffuse source areas that actually are less than the DCGL. Therefore, the 43-37 will be used to screen surfaces and will be considered to be the official results only if no action levels are observed.

2.1.8.4 Any action level observed with the 43-37 will be rescanned with the 43-68B. If no AP is observed with the 43-68B, then there is no AP. APs observed in followup scans using the 43-68B will be handled and documented in the SR per section 2.1.10 below.

2.1.8.5 The fraction scanned with the 43-37 and results should be separately reported in the SR for each survey unit/grid in a similar manner as used for the 43-68B (e.g., 90% scanned with 43-37, one alarm rescanned with 43-68B, no 43-68B AP).

2.1.9 The scan DCGLw Action Levels listed in Table 2 do not include background. The DCGLw action level is based on fixed measurements and does not include 'human performance factors' or'index of sensitivity' factors (see Reference 3.10).

2.1.10 If a net count rate greater than the DCGLw action level' in Table 2 is encountered during the scanning process, then the surveyor should stop and locate the boundary of the elevated area, and then perform a "second phase' fixed point count of at least 30 seconds duration. If the second phase result equals or exceeds the 'DCGLw action level" noted in Table 2, then the surveyor should mark the elevated area appropriately and document the count rate observed and an estimate of the affected area.

2.1.10.1 Class 3 concrete should be scanned up to 10% surface coverage at a rate of about 10 cm per second using the 43-68B probe or 30.5 cm per second using the 43-37 probe. Areas that cannot be accessed should be clearly noted along with the reason for not completing the scan in that area.

- P-SNEC CALCULATION SHEET Calculauon Number Revision Number Page Number E900-05-032 1 Page 5 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Alternate areas should be selected from the remainder to provide the required coverage.

2.1.10.2 Class 2 asphalt should be scanned 10% to 100% surface coverage at a rate of about 10 cm per second using the 43-68B probe or 30.5 cm per second using the 43-37 probe. Areas that cannot be accessed should be clearly noted along with the reason for not completing the scan in that area.

Alternate areas should be selected from the remainder to provide the required coverage.

2.1.10.3 The surfaces of both the concrete and asphalt should-beclear-of debristo ensure detection parameters are not affected.

2.1.11 The minimum number of fixed measurement sampling points indicated by the COMPASS computer program (Reference 3.3) is 11 each for both the concrete and asphalt in OL3-2 and the total of all concrete surfaces in OL3-4 through OL3-6 (see COMPASS output on Attachments 7-1 to 7-5). Fixed point measurements should be lAW Section 2.2. The MDCscan (concrete) using the 43-68b is below the effective administrative DCGLwc, 137 (5077 DPM/1 00cm2 MDCscan @360 cpm bkg <

19834 DPM/1 00cm2 AL). The MDCscan (asphalt) is below the effective administrative DCGLwc. 137 (4405 DPMWIOOcm 2 MDCscan @271 cpm bkg < 19834 DPMWIOOcm 2 AL). The MDCscan using the 43-37 probe is below the effective administrative DCGLwc, 137 (7884 DPM/1 00cm 2 MDCscan @1020 cpm bkg < 19834 DPM11 00cm 2 AL) 2.1.12 All of the concrete in OL3-4 through OL3-6 is considered to be one surface with respect to obtaining static measurements because there is only 70 square meters of material and it is all of the same vintage.

2.1.13 VSP (Reference 3.4) is used to plot all random start concrete and asphalt sampling points on the included diagrams. See Attachments 6-1, 6-3, and 6-5 for VSP sampling point locations).

2.1.14 Some sampling points may need to be adjusted to accommodate obstructions within the survey area. Contact the SR coordinator to report any difficulties encountered when laying out grid sampling points.

2.1.15 Because of the unusual arrangement of the multiple concrete surfaces in OL3, the drawings in Attachment 6 are intended to be as close as practicable to the as-left conditions. If the actual layout is different from that shown, then review with the cognizant SR coordinator, finish the survey if practicable, and mark up the drawings to indicate actual layout.

2.1.16 When an obstruction is encountered that will not allow collection of a sample, contact the cognizant SR coordinatorfor permission to either move or delete the sampling point.

i -SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 1 Page 6 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete

' NOTE If remediation actions are taken as a result of this survey, this survey design must be revised or re-written entirely.

2.2 Measure both fixed point and elevated areas(s) on concrete and asphalt IAW SNEC procedure E900-IMP-4520.04 (Reference 3.2).

3.0 REFERENCES

3.1 SNEC Calculation No. E900-03-018, "Optimize Window and Threshold Settings for the

-- Detection of Cs-137 Using the Ludlum 2350-1 and a 44/10 Nal -Detector%-,W8/703. ------ -

3.2 SNEC Procedure E900-IMP-4520.04, "Survey Methodology to Support SNEC License Termination".

3.3 COMPASS Computer Program, Version 1.0.0, Oak Ridge Institute for Science and Education.

3.5 SNEC Facility License Termination Plan.

3.6 SNEC Procedure E900-IMP-4500.59, nFinal Site Survey Planning and DQA".

3.7 GPU Nuclear, SNEC Facility, 'Site Area Grid Map", SNECRM-020, Sheet 1, Rev 4, 1/18/05.

3.8 SNEC Calculation E900-03-012, Effective DCGL Worksheet Verification.

3.9 SNEC Procedure E900-IMP-4520.06, wSurvey Unit Inspection in Support of FSS Design".

3.10 NUREG-1575, 'Multi-Agency Radiation Survey and Site Investigation Manual", August, 2000.

3.11 Microsoft Office Excel, Version 11.0.5612, Microsoft Corporation Inc., 1985-2003.

3.12 SNEC Procedure E900-ADM-4500.39 'Chain of Custody for Samples" 3.13 CV Yard Survey Design - North West Side of CV, E900-04-005.

3.14 SNEC Calculation 6900-02-028, GFPC Instrument Efficiency Loss Study.

3.15 SNEC Calculation E900-05-031, Use of the 43-37 Detector and Ludlum 239 Floor Monitor for FSS Surveys 3.16 SNEC Survey 43-37 GFPC Measurements OL1, 5/12/05.

3.17 1994 Saxton Soil Remediation Project Report, May 11, 1995.

4.0 ASSUMPTIONS AND BASIC DATA 4.1 The COMPASS computer program is used to calculate the required number of random start systematic samples to be taken in the survey unit (Reference 3.3).

4.2 Data shown on Attachments 8-2 and 8-3 are used as the initial estimates of variability for concrete and asphalt, respectively.

4.3 The MARSSIM Sign Test will be applicable for this survey design. No background subtraction will be performed under this criterion during the DQA phase.

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SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 Page 7 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 4.4 The Visual Sample Plan (VSP) computer code (Reference 3.4) locates the required number of fixed survey points, determined by COMPASS, on the survey maps for asphalt in each survey unit. Fixed survey points for concrete were chosen independent of VSP.

4.5 References 3.5 and 3.6 were used as guidance during the survey design development phase.

4.6 Background reference for concrete was obtained from the Williamsburg concrete study and is 306 com (Attachment 8-1). Asphalt background was determined to be approximately 271 com (Attachment 8-3). Background using the 43-37 probe was estimated to be 1020 cpm (Reference 3.16 and Attachment 8-4).

4.7 .The determination of the physical extent of-this area is based on Reference 3.7. The extent of the SSGS footprint was later modified/extended from OL3 into OL7-1 by virtue of a site walkdown on 4/28/05.

4.8 OL3 has been subjected to extensive remediation.

4.8.1 Contamination was detected in the 'bum area" in OL3-4 and southern portion of OL3-5. Soil was removed, the area was rescanned and additional soil samples were taken.

4.8.2 Soil from the northernmost portion of OL3-5 was removed. See Figures 1 and 3 of the 1994 Saxton Soil Remediation Project Report (Reference 3.17). Soil activity as high as 38 pCi/g was removed from this area. Grids were not designated the way they are in 2005, but one can get an idea of the area remediated when referencing to the location of the Penelec Line Shack.

4.8.3 One grid adjacent to the former SSGS cooling water intake, in OL3-6, was subject to recent remediation when activity was found during an FSS survey of OL9-2. The highest activity found was 14.4 pCi/g. Sampling, following removal of approximately 18 inches of soil, produced no activity greater than the DCGL.

4.9 This survey design uses Cs-1 37 as a surrogate for all SNEC facility related radionuclides in the survey unit. The effective DCGLw is the Cs-137 DCGLw from the SNEC LTP (28,000 dpm/100 cm2 ) adjusted (lowered) to compensate for the presence (or potential presence) of other SNEC-related radionuclides. In addition, an administrative limit (75%) has been set that further lowers the permissible Cs-137 concentration to an effective surrogate DCGLw for this survey area.

4.10 The sample database contained only one sample, which was assayed both on site and off site, with which to determine the effective radionuclide mix for Area OL3. In order to obtain a more representative mix of expected radionuclides, data from OL1 and OL2 were used instead. The decayed set of sample results were input to the spreadsheet titled "Effective DCGL Calculator for Cs-137' (Reference 3.8) to determine the effective DCGLw values for the survey units, then changed to an equivalent surface contamination level. The output of this spreadsheet is shown on Attachment 2-1 which is copied from Reference 3.13. The spreadsheet was previously reviewed.

The 43-68B detector scan MDC calculation is determined based on a 10 cm/sec scan rate, a 1.38 index of sensitivity (95% correct detection probability and 60% false positive) and a detector sensitivity of 23.9% for Cs-137. The 43-37 detector scan MDC calculation is determined based on a 30.5 cm/sec scan rate, a 1.38 index of sensitivity (95% correct detection probability and 60% false positive) and a detector sensitivity of 20.0% for Cs-137.

SNEC CALCULATION SHEET Calculabon Number Revision Number Page Number E900-05-032 l Page 8 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Additionally, the detection system incorporates a Cs-137 window that lowers sensitivity to background in the survey unit. Using the 43-68B probe, the concrete background is approximately 360 corn and the asphalt background is approximately 271 com in 0L3-2.

Using the 43-37 probe, background is approximately 1020 cpm.

4.11 The survey units described in this survey design were inspected. A copy of the OL3 specific portion of the SNEC facility post-remediation inspection report (Reference 3.9) is included as Attachment 9-1.

4.12 No special area characteristics including any additional residual radioactivity (not previously noted during characterization) have been identified in this survey area.

4.13 The decision error for this survey design is 0.05 for the a value and 0.1 for the P value.

4.14 "Special measurements', as described in the SNEC LTP sec 5.5.3.4, are not included in this survey design.

4.15 No additional sampling will be performed lAW this survey design beyond that described herein.

4.16 SNEC site radionuclides and their individual DCGLw values are listed on Exhibit I of this calculation.

4.17 The survey design checklist is listed in Exhibit 2.

4.18 Area factors are shown as part of COMPASS output (see Attachment 7-1) and are based on the Cs-1 37 area factors from the SNEC LTP.

5.0 CALCULATIONS 5.1 All calculations are performed internal to applicable computer codes or within an Excel spreadsheet.

6.0 APPENDICES 6.1 Attachment 1-1 is a diagram of survey units 0L3.

6.2 Attachments 2-1 and 2-5 show the DCGL Calculation Logic - CV Yard Soil & Boulders and the Cs-137 Efficiency Loss with Distance from Source study for GFPC probes (Reference 3.13 and 3.14).

6.3 Attachments 3-1 and 3-2 are copies of the calibration data from typical Nal and GFPC radiation detection instrumentation that will be used in this survey area.

6.4 Attachments 4-1 through 4-3 are the MDCscan calculation sheets for concrete and asphalt surface materials in dpm/100 cm2 using the 43-68B and the MDCscan calculation using the 43-37 probe.

6.5 Attachment 5-1 is the breakdown of concrete and asphalt into miscellaneous survey units.

6.6 Attachments 6-1 through 6-6 show the random sampling points and scan locations, for both concrete and asphalt, and reference coordinates for Survey Units 0L3-2 (MA8-22 and MA8-23) and 0L3-4 through OL3-6 (MA8-24).

6.7 Attachments 7-1 through 7-5 are COMPASS outputs for Survey Units MA8-22 through MA8-24 showing area factors, the number of sampling points in each survey unit, and prospective power.

-SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 1 Page 9 of 11 Subjed Open Land FSS Design - 0L3 Paved Surfaces and Concrete 6.8 Attachments 8-1 through 8-4 show both concrete and asphalt backgrounds and material variability results from the Williamsburg concrete and OL1 concrete and asphalt samples.

The background established for the 43-37 probe is also shown.

6.9 Attachment 9-1 is copied from the most recent inspection report for 0L3.

- ~~SNECCALCIULATIONSHE Calculation Number Revision Number Page Number E900-05-032 1 Page 10 of 11 Subject Open Land FSS Design - 0L3 Paved Surfaces and Concrete Exhibit I SNEC Facility Individual Radionuclide DCGL Values (a) 25 mremly Limit 4 mremly Goal 25 mrem/y Limit (All Pathways) (Drinking Water)

Radionuclide Surface Area Open Land Areas Open Land Areas (b)

(dpm/100cm 2 ) (Surface & Subsurface) (Surface & Subsurface)

(pCl/g) (pCilg)

Am-241 2.7E+01 9.9 -2.3 C-14 3.7E+06 2 5.4 Co-60 7.1 E+03 3.5 67 Cs-137 2.8E+04 6.6 397 Eu-152 1.3E+04 10.1 1440 H-3 1.2E+08 132 31.1 Ni-63 1.8E+06 747 1.9E+04 Pu-238 3.OE+01 1.8 0.41 Pu-239 2.8E+01 1.6 0.37 Pu-241 8.8E+02 86 19.8 Sr-90 8.7E+03 1.2 0.61 NOTES:

(a)While drinking water DCGLs will be used by SNEC to meet the drinking water 4 mrem/y goal, only the DCGL values that constitute the 25 mremty regulatory limit will be controlled under this LTP and the NRC's approving license amendment.

(b) Listed values are from the subsurface model. These values are the most conservative values between the two models (i.e.,

surface & subsurface).

ALC C-~NE;LkO HEE Calculation Number Revision Number Page Number E900-05-032 1 Page 11 of 11 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Exhibit 2 Survey Design Checklist Calculation No. l Location Codes CalulaionNo.E900-05-032, Rev. I I 0L3o_____o_____

ITEM0 Rev.IE FOCUSstatus Reviewer TEM REVIEW FOCUS (Circle One) Initials & Date I Has a survey design calculation number been assigned and is a survey design summary Yes, description provided? c1_ __

2 Are drawings/diagrams adequate for the subject area (drawings should have compass Yes,

.. _.___ headings)? __ . _.

3 Are boundaries properly identified and is the survey area classification clearly indicated? Yes, 4 Has the survey area(s) been properly divided Into survey units LAW EXHIBIT 10 Yes. (

5 Are physical characteristics of the area/location or system documented? Yes, C 6 Is a remediation effectiveness discussion included?Yes, 7Have charateization survey and/or sampling results been converted to units that are Yes, /

comparable to applicable DCGL values? _ _ _

8 Is survey and/or sampling data that was used for determining survey unit variance included? Yes, Is a description of the background reference areas (or materials) and their survey and/or Yes, sampling results included along with ajustification for their selection? .

10 Are applicable survey and/or sampling data that was used to determine variability included? Yes. -

11 Will the condition of the survey area have an impact on the survey design, and has the Yes, probable impact been considered in the design? v Has any special area characteristic including any additional residual radioactivity (not 12 previously noted during characterization) been identified along with its impact on survey Yes,(N/A design?

13 Are all necessary supporting calculations andlor site procedures referenced or Included? Yes, S.

14 Has an effective DCGLw been identified for the survey unit(s)? Yes,_(_ _ _

15 Was the appropriate DCGL4c induded in the survey design calculation? Yes, ( A 16 Has the statistical tests that will be used to evaluate the data been identified? Yes, N/ _ _

17 Has an elevated measurement comparison been performed (Class 1 Area)? Yes, C 18 Has the decision error levels been identified and are the necessary justifications provided? Yes, HA 19 Has scan instrumentation been identified along with the assigned scanning methodology? fe 0j NM _ / 7" 20 Has the scan rate been Identified, and is the MDCscan adequate for the survey design? PI N/A 21 Are special measurements e.g., In-situ gamma-ray spectroscopy required under this design, Yes, and is the survey methodology, and evaluation methods described? _

22 Is survey instrumentation calibration data included and are detection sensitivities adequate? P /N/A v/0fi/; ,

23 Have the assigned sample and/or measurement locations been clearly identified on a diagram e NM.

23Have the or CAD drawing of the survey area(s) along with their coordinates? N/A 24 Are investigation levels and administrative limits adequate, and are any associated actions ~ "/

clearly Indicated?

25 For sample analysis, have the required MDA values been determined.?Yes.LA 26 Has any special sampling methodology been identified other than provided in Reference 6.3? Yes NOTE: a copy of this completed form or equivalent, shall be included within the survey design calculation.

Asphalt Scan Survey and Fixed Point Measurement Grids for Survey Unit 0L3-2 0L3-2 has two sub-units: MA8-22 (concrete) and MA8-23 (asphalt)

VSP provides survey points using a scale relative to the southwestern comer of the survey unit. This is cumbersome as field personnel must measure over large distances (sometimes hundreds of meters) from the single reference point. To remedy this situation, this spreadsheet provides the VSP survey points based on the actual location within each grid.

To identify the fixed point survey locations, start at the grid identifier below left. Go east the number of meters under the "E' column and then move north the number of meters in the "N" column. For simplicity, all measurements have been rounded to the nearest tenth of a meter.

To complete scan surveys, use the scan locations listed below each set of static measurement locations. These grids and partial grid areas should be scanned 100%.

MA8-23 (asphalt) fixed point measurement and scan locations X Y Fixed Grid E N coordinate coordinate Location ID (meters) (meters) (meters) (meters) 1 AQ131 6.1 2.1 46.0671 2.1505 2 AQ130 0.9 2.1 50.9238 2.1505 3 AQ131 , 8.5 6.4 48.4955 6.3566 4 AR131 6.1 0.6 46.0671 10.5626 5 AR130 0.9 0.6 50.9238 10.5626 6 AR131 8.5 4.8 48.4955 14.7686 7 AR131 6.1 9.0 46.0671 18.9746 8 AR130 0.9 9.0 50.9238 18.9746 9 AS131 8.5 3.2 48.4955 23.1806 10 AS131 6.1 7.4 46.0671 27.3866 11 AS130 0.9 7.4 50.9238 27.3866 Scan Grid Location ID 1 AQ131 2 AR130 3 AS131 A7TA2MEMNT Go+I

Aflv'u,8 E SNEC CALCULATION Cd ER SHEET CALCULATION DESCRIPTION Calculation Number Revision Number Effective Date Page Number E90005032 Z0 l o ac I of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete Question 1 - Is this calculation defined as 'In QA Scope'? Refer to definition 3.5. Yes 0D No I]

Question 2-Is this calculation defined as a Design Calculation"? Refer to definitions 3.2 and 3.3. Yes 0l No [3 NOTES: If a 'Yes answer is obtained for Question 1, the calculation must meet the requirements of the SNEC Facility Decommissioning Quality Assurance Plan. If a 'Yes' answer is obtained for Question 2. the Calculation Originator's immediate supervisor should not review the calculation as the Technical Reviewer.

DESCRIPTION OF REVISION APPROVAL SIGNATURES Calculation Originator Tristan M. Tritch/! Of a;L Technical Reviewer W. J. Cooper/ -D Additional Review A. Paynter/l, _

Additional Review

0, '<SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 0 Page 2 of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 1.0 PURPOSE T 1.1 The purpose of this calculation is to develop a final status survey design for open land area OL3 (non-soil only) at the Saxton Nuclear Experimental Corporation (SNEC) facility. The soil portions of OL3 will be surveyed under Open Land FSS Design - 0L3, E900-05-024.

The OL3 fence surveys will be performed under Miscellaneous Chain Link Fences - Survey Design, E900-05-023.

1.2 Survey Area OL3 is an Impacted Class 1 area which encompasses the old on-site driveway, the current parking area, and the soil processing facility (SPF, also known as dirt world) on the SNEC facility decommissioning project. It covers approximately 9,400 square meters (94 1Oim x 1lOm grids). Of that surface area, slightly more than 8180 square meters is soil, 991 square meters is concrete, and 225 square meters is asphalt. Table 5-5 of the SNEC License Termination Plan (LTP) limits the physical size of Class 1 survey areas to 2000 square meters. Due to this area constraint, OL3 will be subdivided into six smaller survey units, namely 0L3-1 through OL3-6, containing 2000, 1800, 1800, 1300, 2000, and 500 square meters, respectively. The corresponding soil areas are 2000, 654, 1800, 1294, 1972, and 464 square meters. Of those areas, only the concrete and asphalt in 0L3-2, and OL3-4 through OL3-6 are involved in this survey design.

1.3 The LTP lists SSGS concrete as Class 3 and asphalt roadway as Class 2 structures. OL3-2 contains 921 square meters of concrete and 225 square meters of asphalt. 0L3-4, OL3-5 and OL3-6 contain 6, 28, and 36 square meters of concrete, respectively. Class 2 structures are limited to 1000 square meters and Class 3 structures are limited to 10,000 square meters, so the four survey units in OL3 are broken down further. OL3-2 concrete (921 square meters) is now MA8-22 and OL3-2 asphalt (225 square meters) is now MA8-

23. The concrete in 0L3-4, 0L3-5, and 0L3-6 (70 square meters) is being given the designation MA8-24.

1.4 The general layout of the survey units is shown on Attachment 1-1. Scale survey drawings of the concrete and asphalt areas are shown on Attachments 6-1, 6-3, and 6-5.

2.0

SUMMARY

OF RESULTS The following information should be used to develop a survey request for this survey unit. The effective DCGLw value is listed below. This value is derived from previously approved derived values for TCV Yard Soil and Boulder Samples" in SNEC calculation E900-04-005 (Reference 3.13).

The US NRC has reviewed and concurred with the methodology used to derive these values. See Attachments 2-1 through 2-3 and Reference 3.8.

Table 1, DCGLw Values I Gross Acvity DCGLw (dpmnlG0 cm') l l 26445 (19834 A.L)

NOTE: A.L is the site Administrative Limit (75% of effective DCGLw) 2.1 Survey Design 2.1.1 Scanning of both concrete and asphalt surfaces shall be performed using a L2350 with 43-688 large area gas flow proportional counter or a 43-37 mextra large" probe calibrated to Cs-137 (see typical calibration information on Attachments 3-1 and 3-2). Generic approval fo ruse of the 43-37 probe is included in Reference 3.15.

. SNEC CA,.iCULATON SHEET Calculation Number Revision Number Page Number E900-05-032 0 Page 3 of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 2.1.2 The instrument efficiency shall not be less than that assumed on Attachment 4-1 as 23.9% - Cs-137 for the 43-68B probe or less than 20.0% - Cs-137 for the 43-37 probe in its lowest efficiency region assumed on Attachment 4-3.

2.1.3 For concrete and asphalt surfaces, an efficiency correction factor (ECF) is applied to compensate for efficiency loss when surveying rough surfaces based on Reference 3.14 and Attachment 2-4. The ECF, using the 43-68B probe is based on a surface irregularity of 3 inches or less. This is conservative as actual observed irregularity is typically less than one inch; however, some rather large deviations exist due to the operation of large earthmoving equipment in the vicinity. Also, the loss of efficiency is based on moving the detector away from a150 .cm! source- If the-area.of-the residual activity is larger, then the efficiency loss would be smaller due to an increase in the detector's "field-of-view".

2.1.4 Using the 43-37 probe, an efficiency correction factor (ECF) is applied to compensate for efficiency loss when surveying rough surfaces based on Reference 3.15 and Attachment 2-5. The ECF, using the 43-37 probe is based on a surface irregularity of 1 inch or less. This is conservative based on the rationale in 2.1.3 above.

2.1.5 The fraction of detectable beta-emitting activity affects the efficiency and is determined by the nuclide mix. The mix detectable beta fraction is determined to be 60% based on Reference 3.13. Because the adjusted DCGLw used is based only on the modified Cs-137 DCGLw, the mix percentage is not applied to the adjusted surrogate DCGLw. The gross activity DCGLw, which would include all the low energy activity and would require an adjustment to the mix percentage, is considerable higher at 44434 dpm 100cm2 . The Cs-137 adjusted surrogate activity already accounts for the detectable beta yield of the mix.

Table 2, Surface Scanning Parameters MDCscan Scan Speed Maximum Distance from Surface DCGLw Action % Coverage (dpm/1 OOcm 2)- (cmlsec) Level 5077 concrete > 200 ncpm Up to 10%

10 3 (gap between detector face &

4405 asphalt surface) > 180 ncpm 10% -100%

7884 30.5 1 (gap between detector face & > 630 ncpm Up to 100%

surface)

See Attachment 2-1, 2-2, 4-1,4-2, and 4-3 for calculations 2.1.6 This MOCscan for concrete (shown in Attachment 4-1) is based on a 360 cpm background. On 317/05, measurements were collected from the SSGS boiler pad in OL1. This data is used for the variability assessment for the COMPASS determination of sample requirements and is shown in Attachment 8-2. Unaffected material backgrounds were determined using data obtained from the Williamsburg Station which resulted in a mean background value of 306 +/- 34.5 cpm as shown in Attachment 8-1.

SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 0 Page 4 of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 2.1.7 The MDCscan for asphalt (shown in Attachment 4-2) is based on a 271 cpm background. On 3/7/05, measurements were collected from the SSGS parking lot asphalt in OL1. This data is used for the variability assessment for the COMPASS determination of sample requirements and is shown in Attachment 8-3.

2.1.8 The MDCscan using the 43-37 probe (shown in Attachment 4-3) is based on a 1020 cpm background. On 5/12/05, measurements were collected on three different surfaces in OL1: the DSB pad, asphalt, and the SSGS boiler pad. This data is shown on Attachment 8-4.

2.1.8.1 Since the efficiency I determined with the same source as used for the 43-68B, the effective area of the detector is assumed to be 100 cm2 for determining the MDCscan. This will underestimate the response of the detector to larger sources but produce similar efficiencies and MDCs as for the 43-68B.

2.1.8.2 Scanning using the 43-37 probe will be done only on flat surfaces with surface irregularities typical of poured concrete or rolled macadam pavement.

Uneven surfaces or edges will be scanned with the 43-68B.

2.1.8.3 Because the 43-37 has a much larger effective surface than the 43-68B and the MDC and action level are based on a 100 cm2 elevated spot, the 43-37 may provide action level count rates on larger diffuse source areas that actually are less than the DCGL. Therefore, the 43-37 will be used to screen surfaces and will be considered to be the official results only if no action levels are observed.

2.1.8.4 Any action level observed with the 43-37 will be rescanned with the 43-68B. If no AP is observed with the 43-68B, then there is no AP. APs observed in followup scans using the 43-68B will be handled and documented in the SR per section 2.1.10 below.

2.1.8.5 The fraction scanned with the 43-37 and results should be separately reported in the SR for each survey unit/grid in a similar manner as used for the 43-68B (e.g., 90% scanned with 43-37, one alarm rescanned with 43-68B, no 43-68B AP).

2.1.9 The scan DCGLw Action Levels listed in Table 2 do not include background. The DCGLw action level is based on fixed measurements and does not include 'human performance factors' or 'index of sensitivity' factors (see Reference 3.10).

2.1.10 If a net count rate greater than the 'DCGLw action level" in Table 2 is encountered during the scanning process, then the surveyor should stop and locate the boundary of the elevated area, and then perform a *second phase" fixed point count of at least 30 seconds duration. If the second phase result equals or exceeds the "DCGLw action" level noted in Table 2, then the surveyor should mark the elevated area appropriately and document the count rate observed and an estimate of the affected area.

2.1.10.1 Class 3 concrete should bescanned up to 10% surface coverage at a rate of about 10 cm per second and 30.5 cm per second using the 43-37. Areas that cannot be accessed should be clearly noted along with the reason for not

SNEC CALCULATION SHEET 'z7-> '*.'

calculation Number Revision Number Page Number E900-05-032 0 Page 5 of 10 Subjec Open Land FSS Design - OL3 Paved Surfaces and Concrete completing the scan in that area. Alternate areas should be selected from the remainder to provide the required coverage.

2.1.10.2 Class 2 asphalt should be scanned 10% to 100% surface coverage at a rate of about 10 cm per second with the 43-68B and 30.5 cm per second using the 43-37. Areas that cannot be accessed should be clearly noted along with the reason for not completing the scan in that area. Alternate areas should be selected from the remainder to provide the required coverage.

2.1.10.3 The surfaces of both the concrete and asphalt should be clear of debris to ensure detection parameters are not affected.

2.1.11 The minimum number of fixed measurement sampling points indicated by the COMPASS computer program (Reference 3.3) is 11 each for both the concrete and asphalt in OL3-2 and the total of all concrete surfaces in OL3-4 through OL3-6 (see COMPASS output on Attachments 7-1 to 7-5). Fixed point measurements should be lAW Section 2.2. The MDCscan (concrete) using the 43-68b is below the effective administrative DCGLwCs. 137 (5077 DPMWIOOcm 2 MDCscan @360 cpm bkg <

19834 DPM/1OOcm 2 AL). The MDCscan (asphalt) is below the effective administrative DCGLwcs. 137 (4405 DPM/IOOcm 2 MDCscan @271 cpm bkg < 19834 DPM/1O0cm 2 AL). The MDCscan using the 43-37 probe is below the effective administrative DCGLwc, 137 (7884 DPM1OOcm 2 MDCscan @1020 cpm bkg < 19834 DPM/1 00cm 2 AL) 2.1.12 All of the concrete in OL3-4 through OL3-6 is considered to be one surface with respect to obtaining static measurements because there is only 70 square meters of material and it is all of the same vintage.

2.1.13 VSP (Reference 3.4) is used to plot all random start concrete and asphalt sampling points on the included diagrams. See Attachments 6-1, 6-3, and 6-5 for VSP sampling point locations).

2.1.11 Some sampling points may need to be adjusted to accommodate obstructions within the survey area. Contact the SR coordinator to report any difficulties encountered when laying out grid sampling points.

2.1.12 Because of the unusual arrangement of the multiple concrete surfaces in OL3, the drawings in Attachment 6 are intended to be as close as practicable to the as-left conditions. If the actual layout is different from that shown, then review with the cognizant SR coordinator, finish the survey if practicable, and mark up the drawings to indicate actual layout.

2.1.13 When an obstruction is encountered that will not allow collection of a sample, contact the cognizant SR coordinator for permission to either move or delete the sampling point.

NOTE If remediation actions are taken as a result of this survey, this survey design must be revised or re-written entirely.

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tAsa 1SNEC CALCULATION SHEET Calculation Number Revision N umber Page Number E9004-5-032 0 Page 6 of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 2.2 Measure both fixed point and elevated areas(s) on concrete and asphalt IAW SNEC procedure E900-IMP-4520.04 (Reference 3.2).

3.0 REFERENCES

3.1 SNEC Calculation No. E900-03-018, 'Optimize Window and Threshold Settings for the Detection of Cs-1 37 Using the Ludlum 2350-1 and a 44/10 Nal Detector", 817/03.

3.2 SNEC Procedure E900-IMP-4520.04, "Survey Methodology to Support SNEC License Termination".

3.3 COMPASS Computer Program, Version 1.0.0, Oak Ridge Institute _for_ Science and Education.

3.5 SNEC Facility License Termination Plan.

3.6 SNEC Procedure E900-IMP-4500.59, "Final Site Survey Planning and DQA".

3.7 GPU Nuclear, SNEC Facility, 'Site Area Grid Map", SNECRM-020, Sheet 1, Rev 4,1/18/05.

3.8 SNEC Calculation E900-03-012, Effective DCGL Worksheet Verification.

3.9 SNEC Procedure E900-IMP-4520.06, "Survey Unit Inspection in Support of FSS Design".

3.10 NUREG-1575, 'Multi-Agency Radiation Survey and Site Investigation Manual", August, 2000.

3.11 Microsoft Office Excel, Version 11.0.5612, Microsoft Corporation Inc., 1985-2003.

3.12 SNEC Procedure E900-ADM-4500.39 "Chain of Custody for Samples" 3.13 CV Yard Survey Design - North West Side of CV, E900-04-005.

3.14 SNEC Calculation 6900-02-028, GFPC Instrument Efficiency Loss Study.

3.15 SNEC Calculation E900-05-031, Use of the 43-37 Detector and Ludlum 239 Floor Monitor for FSS Surveys 3.16 SNEC Survey 43-37 GFPC Measurements OL1, 5/12/05.

3.17 1994 Saxton Soil Remediation Project Report, May 11, 1995.

4.0 ASSUMPTIONS AND BASIC DATA 4.1 The COMPASS computer program is used to calculate the required number of random start systematic samples to be taken in the survey unit (Reference 3.3).

4.2 Data shown on Attachments 8-2 and 8-3 are used as the initial estimates of variability for concrete and asphalt, respectively.

4.3 The MARSSIM Sign Test will be applicable for this survey design. No background subtraction will be performed under this criterion during the DQA phase.

4.4 The Visual Sample Plan (VSP) computer code (Reference 3.4) locates the required number of fixed survey points, determined by COMPASS, on the survey maps for asphalt in each survey unit. Fixed survey points for concrete were chosen independent of VSP.

4.5 References 3.5 and 3.6 were used as guidance during the survey design development phase.

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S NC CALCULATION SHEET Calculation Number Revision Number Page Number E900-05-032 0 Page 7 of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 4.6 Background reference for concrete was obtained from the Williamsburg concrete study and is 306 cpm (Attachment 8-1). Asphalt background was determined to be approximately 271 cpm (Attachment 8-3). Background using the 43-37 probe was estimated to be 1020 cpm (Reference 3.16 and Attachment 8-4).

4.7 The determination of the physical extent of this area is based on Reference 3.7. The extent of the SSGS footprint was later modified/extended from OL3 into OL7-1 by virtue of a site walkdown on 4/28/05.

4.8 OL3 has been subjected to extensive remediation.

4.8.1 Contamination was detected in -the-"bum area"-in-OL3-4-and southem-portion-of--

0L3-5. Soil was removed, the area was rescanned and additional soil samples were taken.

4.8.2 Soil from the northernmost portion of 0L3-5 was removed. See Figures 1 and 3 of the 1994 Saxton Soil Remediation Project Report (Reference 3.17). Soil activity as high as 38 pCilg was removed from this area. Grids were not designated the way they are in 2005, but one can get an idea of the area remediated when referencing to the location of the Penelec Line Shack.

4.8.3 One grid adjacent to the former SSGS cooling water intake, in OL3-6, was subject to recent remediation when activity was found during an FSS survey of OL9-2. The highest activity found was 14.4 pCi/g. Sampling, following removal of approximately 18 inches of soil, produced no activity greater than the DCGL.

4.9 This survey design uses Cs-1 37 as a surrogate for all SNEC facility related radionuclides in the survey unit. The effective DCGLw is the Cs-137 DCGLw from the SNEC LTP (28,000 dpm/100 cm2) adjusted (lowered) to compensate for the presence (or potential presence) of other SNEC-related radionuclides. In addition, an administrative limit (75%) has been set that further lowers the permissible Cs-137 concentration to an effective surrogate DCGLw for this survey area.

4.10 The sample database contained only one sample, which was assayed both on site and off site, with which to determine the effective radionuclide mix for Area 0L3. In order to obtain a more representative mix of expected radionuclides, data from OL1 and OL2 were used instead. The decayed set of sample results were input to the spreadsheet titled 'Effective DCGL Calculator for Cs-1 37" (Reference 3.8) to determine the effective DCGLw values for the survey units, then changed to an equivalent surface contamination level. The output of this spreadsheet is shown on Attachment 2-1 which is copied from Reference 3.13. The spreadsheet was previously reviewed.

The 43-68B detector scan MDC calculation is determined based on a 10 cm/sec scan rate, a 1.38 index of sensitivity (95% correct detection probability and 60% false positive) and a detector sensitivity of 23.9% for Cs-137. The 43-37 detector scan MDC calculation is determined based on a 30.5 cm/sec scan rate, a 1.38 index of sensitivity (95% correct detection probability and 60% false positive) and a detector sensitivity of 20.0% for Cs-137.

Additionally, the detection system incorporates a Cs-137 window that lowers sensitivity to background in the survey unit. Using the 43-68B probe, the concrete background is approximately 360 cpm and the asphalt background is approximately 271 com in OL3-2.

Using the 43-37 probe, background is approximately 1020 cpm.

~~~SNEC'CALCULALTIONShE Calculation Number Revision Number Page Number E900-05-032 0 Page 8 of 10 Subject Open Land FSS Design - OL3 Paved Surfaces and Concrete 4.11 The survey units described in this survey design were inspected. A copy of the OL3 specific portion of the SNEC facility post-remediation inspection report (Reference 3.9) is included as Attachment 9-1.

4.12 No special area characteristics including any additional residual radioactivity (not previously noted during characterization) have been identified in this survey area.

4.13 The decision error for this survey design is 0.05 for the a value and 0.1 for the 3value.

4.14 'Special measurements", as described in the SNEC LTP sec 5.5.3.4, are not included in this survey design.