ML043290291

Final Status Survey Release Record FB-0200 Control and Computer Room Footprint Survey Unit 1

ML043290291
Person / Time
Site:	Maine Yankee
Issue date:	11/17/2004
From:	Pillsbury G Maine Yankee Atomic Power Co
To:	NRC/FSME
References
FB-0200-01, Rev 0
Download: ML043290291 (19)

Text

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-0200 CONTROL AND COMPUTER ROOM FOOTPRINT SURVEY UNIT 1 Prepared By: ,v g5 Date: i/Z9o S ign ure Printed Nam Reviewed By: a& Date: lI Q_

FSS Specialist - Signature Printed Name Reviewed By:

ndependent Review - Signature Date: (/ y %

Approved By: Date:

Prnhted Name

,frintentfeg Signature

/Printed Name/

Approved By: 04- ,e Date: 4IZ7ZO0s/

FSS, MIOP - Signature //

Printed Name Revision 0

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-0200 CONTROL AND COMPUTER ROOM FOOTPRINT SURVEY UNIT 1 A. SURVEY UNIT DESCRIPTION FB-0200 is the survey area located in the footprint of the former Service Building where the Control Room and Computer Room were located. The northwest corner of the Service Building is positioned at coordinates 407735 N and 623965 E using the Maine State Coordinate System (West Zone) NAD 1927, and is shown on map FB 0200-SITE-A in Attachment 1. The entire footprint survey area of approximately 485 m2 was designated as Survey Unit 1.

B. SURVEY UNIT DESIGN INFORMATION Per LTP Table 5-1 B, FB-0200 was designated as Class 3 because it had no history of surface or airborne contamination, and there were no cross-contaminated systems residing in, or traversing through this area. The survey area was used as the plant operations Control Room including a kitchen area, and the Computer Room contained the plant computer systems and office space.

The survey unit design parameters are shown in Table 1. Given a relative shift of 3.0, it was determined that 14 direct measurements were required for the Sign Test. Measurement locations were randomly determined and are illustrated on the map FB 0200-02 (Attachment 1). All direct measurements consisted of soil samples obtained at the required locations. The samples are analyzed with laboratory gamma spectroscopy.

A I% to 10% scan coverage of the area was required. A minimum 10% surface scan (> 48.5 m2) was accomplished by scanning eight grids with a total area equaling 50.75 M2 . The location of the scan areas are shown on map FB 0200-01 in Attachment 1. The survey instruments used, their MDCs, and alarm setpoints are provided in Attachment 2.

Background values were established for the scan measurements based on local scaler values in the survey unit. These background values were used to establish scan alarm set-points.

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TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria I Basis Area 485 m2 No limit for Class 3 Area Based on an adjusted LBGR of Number of Direct 14 2.69 pCi/g, sigma' of 0.17 Measurements Required pCi/g, 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 7 grids sized 2.5 m x 2.5 m Class 3 Area I grid sized 2 m x 3.5 m Area Factor N/A Class 3 Area Scan Survey Area 50.75 m} Class 3 Area> 10%

Background -

Average background +/- DI 6-150, EC-009-01, SSPA-3 (scan) 1000 c/in LTP Section 5 Scan Alarm 3 sigma of background EC-009-01 (Reference 5)

DCGL 2 3.2 pCi/g LTP Revision 3 (Reference I and 2)

DCGLEMC N/A Class 3 Area C. SURVEY UNIT RESULTS As required, 14 direct soil measurements were made. The results of the soil sample analyses are shown in Table 2. All direct measurements were below the DCGL.

There were eight scan grids as shown on survey map FB 0200-01 (Attachment 1). Scan alarms occurred in two of the eight grids. The investigation results for the two alarm grids are discussed in Section D.

LTP Table 5-IC, Footnote a, Sigma for R0200 yard east.

2 Refer to Section H for an additional discussion relating to the design DCGL.

FB-0200-0 1, Revision 0 Page 3 of 19

TABLE 2 DIRECT MEASUREMENTS Sample Number Cs-137 (pCi/g)(')

FB0200-1-3S009SS < 0.028 FB0200-1-3SOlOSS < 0.029 FBO200-1-3SO 1 SS < 0.031 FBO200-1-3S012SS < 0.030 FBO200-1-3S013SS < 0.030 FBO200-1-3S014SS < 0.026 FBO200-1-3SO15SS <0.023 FBO200-1-3SO16SS < 0.027 FBO200-1-3S017SS < 0.027 FBO200-1-3SO18SS < 0.026 FBO200-1-3SO19SS < 0.029 FBO200-1-3SO20SS < 0.029 FBO200-1-3SO21SS < 0.028 FBO200-1-3S022SS < 0.027 Mean 0.028 Median 0.028 Standard Deviation 0.002 Range 0.023 - 0.031 (1) < Indicates results were below the listed MDA value.

The samples were also analyzed for Co-60 at a similar MDA; all were less than MDA.

D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS Of the eight grids scanned within the Control and Computer Room Footprint, Grids #1 and

1. 2 alarmed. The two grids were re-scanned and a soil sample was taken at the highest count rate location. The soil samples were analyzed by gamma spectroscopy and no plant-derived fission products were detected. The results of the investigation measurements are tabulated in Attachment 3.

E. SURVEY UNIT DATA ASSESSMENT An analysis of the direct sample measurement results, including mean, median, standard deviation, and sample result range are provided in Table 2. There was no detectable plant-derived fission product from the 14 soil samples collected, and the final sigma was less than the design sigma (and no additional samples were required).

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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) for disturbed soil from the survey unit sample mean activity (0.028 pCi/g). The result is a net value of-0. 162 pCi/g.

This would equate to an annual dose rate of 0.0 mrem/y. However, for the purposes of demonstrating compliance with the radiological criteria for license termination and the enhanced State Criteria, background activity is not subtracted from the soil sample analysis activity values.

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 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. 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 2.39 pCi/g.

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

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 was less than the design sigma. Thus, no additional measurements were required.

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H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The survey design used 3.2 pCi/g as the DCGL. The lower DCGL (applicable to the restricted area) was chosen due to the survey unit's proximity to the Primary Auxiliary Building. Subsequently, the DCGL applicable to this survey unit was changed to 2.39 pCi/g (Reference 4). The revised DCGL would not result in additional sample requirements (design relative shift >> 3) and soil measurement MDAs were well below the revised DCGL.

The LTP revision has no effect on this survey.

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 wvere less than the DCGL of 2.39 pCi/g.

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 wvas 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 normal distribution, with no 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 1. Scanning resulted in two verified alarms. Investigations of the alarm grids yielded no indication of plant-derived fission products.

It is concluded that FBO200 Survey Unit 1 meets the release criteria of I0CFR20.1402 and that State of Maine enhanced criteria.

J. REFERENCES

1. Maine Yankee License Termination Plan, Revision 3, Maine Yankee letter to the NRC, MN-02-048, dated October 15, 2002

2. Maine Yankee License Termination Plan, Revision 3 Addenda, Maine Yankee letter to the NRC, MN-02-061, dated November 26, 2002

3. NRC letter to Maine Yankee, dated February 28, 2003, Approval of LTP Rev. 3 and Addenda

4. MY letter to the NRC, MN-03-049, dated September 11, 2003, "Proposed Change:

Revised Activated Concrete DCGL and More Realistic Activated Concrete Dose Modeling"

5. Maine Yankee Engineering Calculation, EC-009-01 FB-0200-0 1, Revision 0 Page 6 of 19

Attachment 1 Survey Unit Maps FB-0200-01, Revision 0 Page 7 of 19

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2) -623,965E (West Zone) NAD 1927

Maine Yankee Map ID#:FB3 0200-01 Decommissioning Team Iaine Yankee DecoImissioningProjectSurley Form Revised: 11-11-03 Survey Type: El Characterization El Turnover CK Final Status Survey Survey Area Name: Control & Computer Room Footprint Control & Computer Room Footprint (Service Building Phase 11) FEZL Survey Scans 001-008 Origin, NW Corner 407,735N / 623,965E 2.Om F

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C FB-0200-01, Revision 0 Page 9 of 19 10% Scan Total Area = 485 sq-m

Maine Yankee Map ID#:FB 0200-02 Decommissioning Team Maitie Y'ankeeDeconntmissiontingProjectSurveyjFormiitIRevised: 10-29-03 Survey Type: = Characterization = Turnover X Final Status Survey lSurvey Area Name: Service Building Phase 11 Service Building Phase 11 Footprint Final Status Survey Direct Points 009-022 Origin, NW Comer 20m 15 m 1OM 5m 1m 407,735N / 623,965E i

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25m FB-0200-01, Revision 0 Page 10 of 19 Total Area = 485 sq-m

Attachment 2 Survey Unit Instrumentation FB-0200-01, Revision 0 Page IIof 19

TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN I Probe S/N (type) l 2617 725328 (SSPA-3) 1625 2258 (SSPA-3) 2488 2258 (SSPA-3)

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

FSS-I 0.02 to 0.13 FSS-2 0.02 to 0.13 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Detector I SPA-3 I Comments Scan MDC 5.9 Design Scan MDC (pCi/g) . (Reference 2)

DCGL 2.39 DCGL for land areas within (pCi/g) the RA Investigation Level (Alarm Setpoint) 15,590 3 sigma of background (cpm) _

FB-0200-01, Revision 0 Page 12 of 19

Attachment 3 Investigation Table FB-0200-01, Revision 0 Page 13 of 19

TABLE 3-1 INVESTIGATION RESULTS Alarm Initial Scan Maximum Investigation Investigation Setpoint Alarm Investigation Scan value Result3 Location (cpm) (cpm) Number (cpm)  ! Cslg)

Grid I1 15,590 16,060 l XBO200-01-3-S00I1 20,000 l <2.81E-2 I Grid 2 J 15,590 15,900 J XB0200-01-3-S002 22,800 1 < 3.06E-2

• Samples were also analyzed for Co-60; all were less than an MDA of 0.05 pCi/g.

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Attachment 4 Statistical Data FB-0200-01, Revision 0 Page 15 of 19

Survey Package FBO200 Unit I Soil Sign Test Summary

, ' i5,:'.' Eauainu Values'X '2' i - -.

Di-~ iini ts , T ,

Survey Package: FBO200 Control/Computer Rooms Survey Unit: 01 Evaluator: GP DCGL,: 2.39E+00 DCGL,.: 2.39E+00 LBGR: 1.20E+00 Sigma: 1.70E-01 Type I error: ^ . 0.05 Type II error: 0.05 Nuclide: CS-137 Soil Type: NIA Z.a: - ' -'.1.645 Z1-D .-. "" :1.645 Sign p: '.'". '0.99865 Calculated Relative Shift: . ' 7.0 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift is >3 N-Value: 1 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

N-Value+20%: 14 Number of Samples:  ;: 14 Median: 2;82E-02 0 Mean:  ;:,-"-, 2.78E-02 Net Sample Standard Deviation: s;:' b 2.OE-03 Total Standard Deviation: . 2.00E-03 SRSS Maximum: n-,,' -3.06E-02 Adjusted N Value: ,14 S+ Value: j, A.,j14 Critical Value: . 10 Sign test results: .> ':Pass e-.

C'tdrlsilat. fl o 'N.W C niriie*t Sufficient samples collected. 'Pass Maximum value <DCGL

: Pass Median value <DCGL.,: Ps Mean value <DCGL,: Pass Maximum value <DCGLemc: Pass Total Standard Deviation <=Sigma: Pass Criteria comparison results: . Pass The survey unit passes all conditions: - .:Pass FBO200-SU1-SoilSign 10/18/04 9:23 AM FB-0200-01, Revision 0 Page 16 of 19

FB-0200 SU-1 Quantile Plot 0.035 0.03 A. 4 ,

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One-Sample T-Test Report Page/Date/Time 2 10/18/04 9:13:03 AM Database C:\Program Files\NCSS97\FB0200SU1.S0 Variable C2 Plots Section Histogram of FB-0200, SU-1 U,

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One-Sample T-Test Power Analysis Page/Date/Time 2 10118/04 9:14:52 AM Chart Section Retrospective Power Curve 1.0- 6--------------

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• I 0o5 10 1:5 Survey Unit Mean (pCi/g)

FB-0200-01, Revision 0 Page 19 of 19