ML043290324

Final Status Survey Release Record FB-2000 Bailey Barn Footprint Survey Unit 1

ML043290324
Person / Time
Site:	Maine Yankee
Issue date:	11/17/2004
From:	Donna Anderson Maine Yankee Atomic Power Co
To:	NRC/FSME
References
FB-2000-01, Rev 0
Download: ML043290324 (20)

Text

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-2000 BAILEY BARN FOOTPRINT SURVEY UNIT I Prepared By: A i.

• jj. SuA Date: /12 ID 0L4 FSS Engincer - Signature

b. ArA]FR60Af Printed Name Reviewed By: I L Date: Int- o3 FSS Speciafist- Signature

)'% 1gntur Printed Name Revieved By:  ? Date: -- Ilyle Z Independent Revicew-Signature Approved By: , gDate: 7°/f0

-#rinteSS,Printed Name IOP-Signature Printed Name

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-2000 BAILEY BARN FOOTPRINT SURVEY UNIT I A. SURVEY UNIT DESCRIPTION FB-2000 survey unit encompasses the footprint of the former Bailey Barn, an outbuilding that was used as a storage building for farm equipment, chemicals, flammables and environmental monitoring supplies/equipment. The building stood adjacent to the Environmental Services Building along the Back River, outside and to the northeast of the Industrial and Restricted Areas at coordinates 409400N and 625265 E using the Maine State Coordinate System (West Zone) NAD 1927. The building footprint is shown in relation to other major site structures on Map FB 2000 SITE, Attachment 1.

The Bailey Barn was a wood frame structure with a concrete floor. In preparation for decommissioning activities, the building and concrete slab foundation were removed.

Following slab excavation, the remaining soil was leveled and spread evenly throughout the survey unit. The building footprint occupied a space of approximately 230 m2 .

B. SURVEY UNIT DESIGN INFORMATION The Bailey Barn footprint survey area was located outside of the Industrial Area. The only radioactive material stored in the former structure was several sealed NORM-containing luminous temperature detectors. Characterization surveys performed on the barn indicated total and removable beta activity levels were below the minimum detectable activity (MDA) for the instrumentation used to perform the surveys. Removable alpha activity was also found to be less than MDA. Historical site assessment results indicated an absence of radiological events recorded for this area. As an outcome of the characterization surveys and historical knowledge assessment, FB-2000 was established as a Class 3 survey area and Final Status Surveys 'were performed in accordance with Section 5 of the LTP.

The survey unit design parameters for FB-2000 as a Class 3 land survey are shown in Table

1. To calculate the number of soil samples required for the Sign Test, the sigma value of 0.23 pCi/g (Cs-137) applicable to R1800 Bailey House Land Area (Table 5-1 C of the LTP Rev. 3)1 was used, rather than the sigma of 245 dpm/I00 cm2 from B-2000 Bailey Barn Slab.

Following removal of the barn foundation, backfill was not required to bring the footprint to ground level. Therefore, the sigma value from the Bailey House Land Area was determined to be more applicable for this survey unit than that established for the former barn structure.

Given a relative shift of 3.0, it was determined that 14 direct soil sample points were required for the Sign Test. Direct measurement locations were randomly generated and are shown on map FB 2000 DP (Attachment 1). Soil samples were analyzed with laboratory gamma spectroscopy.

Reference I FB-2000-01, Revision 0 Page 2 of 20

In accordance with the LTP, scans covering I % to 10% of the 230 in2 area were required for the Class 3 survey unit. This was accomplished by scanning seven approximately 4 m2 areas (equaling 28 m2 , which is conservatively greater than 10%). Locations of the survey scans are shown on map FB 2000 SS (Attachment 1). The survey instruments used, their MDCs and scan investigation levels are provided in Attachment 2.

Background values were based on local scaler values in the survey unit. These background values were used to establish scan alarm setpoints.

TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit Dcsign Criteria T Basis Area 230 m2 No limit for Class 3 Area Based on adjusted LBGR of Number of Direct 14 3.51 pCi/g, sigma of 0.23 pCi/g, Measurements Required and relative shift of 3.0.

Type I = Type II = 0.05 Sample Area N/A Class 3 Area Sample Grid Spacing N/A Class 3 Area Scan Grid Area 4 mr (2 m x 2 m) Class 3 Area Area Factor N/A Class 3 Area Scan Survey Area 12% (28 m) Class 3 Area Background Hi__A_ __ _ _ _4_- _arty T__________________

SSPA-3 (scan) Average background + LTP Revision 3, Section 5.5.2.d

__ __ __ __ _ _ __ _ _ _ _ _ _ _ _ I 10 0 0 c/inm_ _ _ _ _ _ _ _ _ _ _ _ _

Scan Investigation Level 3 sigma of background EC-009-0 12

____ _______ ___ ____ ___ See T able 2-2 _ _ _ _ _ _ _ _ _ _ _ _ _ _

DCGL 4.2 pCi/g LTP Revision 3, Section 6.7 Design DCGLEMC N/A Class 3 Area C. SURVEY UNIT RESULTS As required, 14 direct soil measurements were performed and the results are presented in Table 2. All direct measurements were below the DCGL. No scan alarms occurred within the survey unit scan locations; thus, no investigations were required.

2 Reference 6 FB-2000-01, Revision 0 Page 3 of 20

TABLE 2 DIRECT MEASUREMENTS Sample Number Cs-137 (pCi/g) Uncertainty FB2000-1-3SOOISS < 2.44E-02 FB2000-1-3SOO2SS 2.06E-02 + 1.1 7E-02 FB2000-1-3SOO3SS < 2.22E-02 _

FB2000-1-3SOO4SS 3.83E-02 + 2.48E-02 FB2000-1-3SOO5SS < 2.61E-02 _

FB2000-1-3SOO6SS < 2.14E-02 FB2000-1-3SOO7SS < 2.3 1E-02 FB2000-1-3SOO8SS < 2.20E-02 FB2000-l-3SOO9SS < 2.43E-02 FB2000-l-3SOIOSS < 2.32E-02 FB2000-1-3SO ISS < 2.26E-02 FB2000-1-3SO12SS < 2.38E-02 FB2000-1-3S013SS < 2.16E-02 FB2000-1-3SO14SS < 2.34E-02 Mean 2.41E-02 _

Median 2.32E-02 Standard Deviation 4.33E-03 Range 2.06E 3.83E-02 NOTE: Samples wvere also analyzed for Co-60; all wvere less than the MDA of 0.03 pCi/g.

"<" indicates MDA value D. SURVEY UNIT INVESTIGATIONS AND RESULTS No investigations were required.

E. SURVEY UNIT DATA ASSESSMENT An analysis of the direct sample measurement results, including the mean, median, standard deviation, and sample range, is provided in Table 2. Of the 14 soil samples collected, only 2 samples identified detectable Cs-137 activity, with the reported values less than 1% of the DCGL. The sample activity and Minimum Detectable Activities are listed in Table 2. The mean and median activities were also less than the DCGL. In addition, Co-60 was not identified in any of the 14 samples.

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For illustrative purposes, as indicated in LTP Section 5.9.3, a simplified general retrospective dose estimate can be calculated from the average residual contamination level by subtracting the established mean fallout Cs-137 background value (0.19 pCi/g)3 for disturbed soil from the survey unit sample mean activity (0.0241 pCi/g). The result is a net value of -0.166 pCi/g. This would equate to an annual dose of 0.0 mrem/year. However, for purposes of demonstrating compliance with the radiological criteria for license termination and the enhanced State criteria, background activity was not subtracted from the soil sample analysis activity values and less than detectable activities were assumed to be present at the detection limit.

F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with this Survey Unit, including relevant statistical information. Based on survey unit direct measurement data, this attachment provides the Sign Test Summary, Quantile Plot, Histogram, and Retrospective Power Curve.

1. The Sign Test Summary provides an overall summary of design input (Table I) and resulting calculated values used to determine the required number (N) of direct measurements (per LTP Section 5.4.2). The Sign Test Summary is a separate statistical analysis that also calculates the mean, median, and standard deviation of the direct measurements.

The critical value and the result of the Sign Test are provided in the Sign Test Summary table, as well as a listing of the key release criteria. As is shown in the table, all of the key release criteria were clearly satisfied for the FSS of this survey unit.

2. The Quantile Plot was generated from direct measurement data listed in Table 2 and indicates general symmetry about the median. The data set and plot are consistent with expectations for a Class 3 survey unit. All of the measurements are well below the DCGL of 4.2 pCi/g for land outside the restricted area.

3. A Histogram Plot was also developed based on the direct measurement values. This plot shows that the direct data were essentially a log-normal distribution with no significant outliers.

4. A Retrospective Power Curve was constructed, based on FSS results. The curve shows that this survey unit having a mean residual activity at a small fraction of the DCGL has a high probability ("power") of meeting the release criteria. Thus, it can be concluded that the direct measurement data support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and that the data quality objectives were met.

3 See Attachment E to Maine Yankee Procedure PMP 6.7.8 (Reference 5).

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G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class 3 area; the FSS results were consistent with that classification. The direct measurement sample standard deviation wvas less than the design sigma. Thus, a sufficient number of sample measurements were taken and no additional measurements were required.

H1. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON EXTENT OF RESIDUAL ACTIVITY The FSS of Survey Unit I was designed and performed using the criteria of the approved LTP Revision 3 Addenda 4 . The only subsequent LTP changes (with potential impact to this FSS) included the proposed license amendment related to modifications of the activated concrete remediation plan, submitted September 11, 20035 and approved by the NRC 6 . The license amendment lowered the surface soil DCGL to 2.39 pCi/g for areas inside the Restricted Area. However, the changes do not apply to this survey unit as the surface soil DCGL for areas outside the restricted area remain unchanged.

1. CONCLUSION The FSS of this survey unit was designed based on the LTP designation as a Class 3 area.

The survey design parameters are presented in Table 1. The required number of direct.

measurements was determined for the Sign Test in accordance with the LTP. As presented in Table 2, all direct measurements were less than the DCGL of 4.2 pCi/g Cs-1 37.

A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied. The direct measurement sigma was determined to be less than that used for design, thus indicating that a sufficient number of samples was taken.

The Retrospective Power Curve shown in Attachment 4 confirmed that sufficient samples were taken to support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and the data quality objectives were met. Attachment 4 also revealed that direct measurement data represented essentially a log-normal distribution with no significant outliers.

The scan survey design for this survey unit was developed in accordance with the LTP with significant aspects of the design discussed in Section B and Table I. Scanning resulted in no verified alarms; therefore, no investigations were required.

It is concluded that FB2000 Survey Unit I meets the release criteria of I OCFR20. 1402 and the State of Maine enhanced criteria.

4 Reference I 5 Reference 3 6 Reference 4 FB-2000-01, Revision 0 Page 6 of 20

J. REFERENCES

1. Maine Yankee License Termination Plan, Revision 3, October 15, 2002 and Addenda, Maine Yankee letter to the NRC, MN-02-06 1, dated November 26, 2002

2. NRC letter to Maine Yankee, dated February 28, 2003

3. Maine Yankee letter to the NRC, MN-03-049, dated September 11, 2003

4. Issuance of License Amendment No. 170, NRC letter to Maine Yankee, dated February 18, 2004

5. Maine Yankee PMP 6.7.8, FSS Data Processing and Reporting, Attachment E, Approach for Dealing with Background Radioactivity for Maine Yankee Final Status Surveys

6. EC-009-01 (MY), Instrumentation Selection and MDC Calculation FB-2000-01, Revision 0 Page 7 of 20

Attachment 1 Survey Unit Maps FB-2000-01, Revision 0 Page 8 of 20

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626, 000 E SURVEY UNIT 1, FB 2000 Note: Grid based on Maine State Coordinate System NorthWest Comer of Bailey Bam at Coordinate -409,374N rn

-625,265E (West Zone) NAD 1927

Maine Yankee ilfahize Y'an kee Deco twissionhigProjectS ' rey FORi Map ID#: FB 2000-BKG Decommissioning Team IcrinaStus Surve liSurvey111 Revised: 5-3-04 Survey Type: -- Characterization -- Turnover U Final Status Survey ISurvey Area Name: Bailey Barn Bailey Barn Final Status Survey Background Map F13-2000-01, Revision 0 Page 10 of 20 Soil Footprint Total Area - 230 sq-r

Maine Yankee labine Yankee DecoimiissiottitigProjectSurvrtey Forin Map ID #: FB 2000 SS Decommissioning Team IIRevised: 5-3-04 Survey Type: - Characterization = Turnover W Final Status Survey I Survey Area Name: Bailey Barn Bailey Barn Final Status Survey Survey Scans S001 - S007 N,

FB-2000-0 1, Revision 0 Page I I of 20 Grids are approximately 2m x 2m Soil Footprint Total Area - 230 sq-m Grids are approximately 2m x 2m Soil Footprint Total Area 230 sq-rn

MaineYan eie Ylkee Deconimissionitig Project Surv'e' ForIz 'Map ID#: FB3 2000 DP Decommissioning Team AfIfl ie ciiiisiiigijc evised: 3-24-04 Survey Type: _ Characterization _ Turnover

• Final Status Survey I Survey Area Name: Bailey Barn Bailey Barn Final Status Survey Direct Points 001 - 014 N

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5m 0,0 5m 10m 15m FB-2000-0 1, Revision 0 Page 12 of 20 N Soil Footprint Total Area - 230 sq rn N == 14 14 Soil Footprint Total Area 230 sq-rn

Attachment 2 Survey Unit Instrumentation FB-2000-0 1,Revision 0 Page 13 of 20

TABLE 2-1 INSTRUMENT INFORMATION I E-600 S/N I Probe SIN (type) I 1 2491 J 2254 (SSPA-3) l 2620 1 726554 (SSPA-3)

IIPGe Detectors for Lab Analysis of Volumetric Samples Detector Number I MDC (pCi/g)

FSS-l I 0.015 to 0.03 l FSS-2 0.015 to 0.03 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Detector SSPA-3 Comments Scan MIDC 5.9 pCi/g Cs-137 Design Scan MDC,

____ ____ ____ LTP Table 5-6 (Reference 1)

Approved DCGL for land areas DCGL 4.2 pCi/g Cs-137 outside the Restricted Area, II LTP Section 6.7 (Reference 1)

Investigation Level 13,215 3 sigma of Background, (Alarm Setpoint) , cpm EC-009-01 (MY) (Reference 6)

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Attachment 3 Investigation Tables (None Required)

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Attachment 4 Statistical Data FB-2000-01, Revision 0 Page 16 of 20

Survey Package FB-2000 Unit I Soil Sign Test Summary

• ;Eval^Uat noinputaIUOs1-*<t ff ..... -.s I i CrrTt Survey Package: FB-2000 Survey Unit: 01 Evaluator: Anderson DCGL.: 4.20E+00 DCGLem: N/A LBGR: 3.51 E+ _00 Sigma: 2.30E-01 Type I error: . :0.05 -i>

Type II error: 0.05 Nuclide: CS-1 37 Soil Type: N/A Cu Nate-Value: FC Ri ZNu: - . 1645 Z1.0.

Sign p: N. 0.9oS98l6e5 Calculated Relative Shift: ; 23 .0 Relative Shift Used: ;ti4M *j0 .- Uses 3.0 if Relative Shift is >3 N-Value: . .fi N-Value+20%: rT;',-;. ,1 Number of Samples:*Jg?^ :.-i4 Median: 1-0.22 82E 02 Net Sample Standard Deviation:

• N i4.33E-03 Total Standard Deviation: %7.!t.4.33E:03 SRSS Maximum: > 3 83E 02 Adjusted N Value: > v>< ____ ________

S+ Value:  :

Critical Value: - i __ __ __ __ __

Sign test results: 1I'i .;..Pass Sufficient samples collected: 71-'fa, 6 F:Pass Maximum value <DCGL,: 74  :.Pass Median value <DCGL,: . Pass Mean value <DCGLw: t Pass Maximum value <DCGLemc: , - Pass Total Standard Deviation <=Sigma:  :. Pass Criteria comparison results -z .Pass The survey unit passes all conditions: i. .<-Pass FB-2000-SUI-SoHSIign.xls 10/12/04 12:40 PM FB-2000-01, Revision 0 Page 17 of 20

FB-2000 SU-1 Quantile Plot 0.045 -f 0.04 0.035 0-%

w a- 0.03 t0

n. 0.025

• Activity (pCi/g) ea =

o0 00 . .* * *

• D ' * '

• 0 0 ~

To i;-. 0.02 -Median (pCi/g) 0.015 0.01 -t 0.005 1 0

0 25 50 75 100 Percent

One-Sample T-Test Report Page/Date/Time 2 7/22/04 9:02:54 AM Database Variable C2 Plots Section Histogram of FB-2000, SU-1 12.000 Un C, 9.000 E

6.000

.0 E

z 3.000

_ W A B 1X 1I 0.000 bI E . w X-W w f 0.020 0.025 0.030 0.035 0.040 Activity (pCilg)

FB-2000-01, Revision 0 Page 19 of 20

One-Sample T-Test Power Analysis Page/Date/Time 2 7/22/04 9:03:51 AM Chart Section Retrospective Power Curve 1.0- , .. ....- S.- -.....

0.8- - - - -

.- \\ -.

_ _ I a) 0.6-I 0

0- I 0.4 0.2 0.0 0

2i Survey Unit Mean (pCi/g)

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