ML043500359

Final Status Survey Release Record FR-0500-01, Rev 0, Bailey Point Survey Unit 1.

ML043500359
Person / Time
Site:	Maine Yankee
Issue date:	12/07/2004
From:	Pillsbury G, Randall D Maine Yankee Atomic Power Co
To:	NRC/FSME
References
FR-0500-01, Rev 0
Download: ML043500359 (20)

Text

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0500 BAILEY POINT SURVEY UNIT I Prepared By: S 6: IL Date: /2 9 FSS Engineer - Signature Dre 9 h14>/

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MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0500 BAILEY POINT SURVEY UNIT I A. SURVEY UNIT DESCRIPTION FR-0500 Survey Unit 1, Bailey Point, consists of the location in which a small volume of contaminated soil, gravel and/or asphalt media, originating from inside the Restricted Area, was temporarily placed. This area was determined to have elevated activity based on the results of the characterization survey and is believed to have been remediated as part of the characterization effort. In accordance with the License Termination Plan (LTP), (Reference

3) the subject area was reclassified into a Class I survey unit.

The area requiring remediation measured approximately 1.2 m by 0.75 m (4 foot by 2.5 foot).'

The initial design for Bailey Point was intended to be a Class I survey unit that was completely surrounded by a Class 2 buffer survey unit. Alternately, it was deemed to be more efficient to combine both of these small survey units into one Class I unit. This was done, producing the 8 m by 8 m area that is now designated FR-0500 Survey Unit 1.

The survey unit area located at approximately grid coordinates 407,000 N and 624,200 E is shown in relation to other major site structures in map FR 0500 SITE. All maps referenced in this release record are provided in Attachment 1, unless othervise noted. The survey unit total area including suitable buffer zone is approximately 64 m2 .

B. SURVEY UNIT DESIGN INFORMATION FR-0500 Survey Unit I was designated a Class I survey unit. The survey unit design parameters are summarized 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 determined using the fixed grid with a random start point method and are illustrated on the map FR 0500-01c. All direct measurements consisted of soil samples obtained at the required location. The samples were analyzed with laboratory gamma spectroscopy.

For a Class 1 area, 100% scan coverage was required.' Scan areas are indicated on map FR 0500-01 a. Twenty-five scan grids of varying sizes were made to provide a total of 64 m2 scan coverage. The survey instruments used, their MDC, and alarm setpoints are provided in Attachment 2.

Background values were established for the scan measurements based on local scaler values in survey area. These background values were used to establish scan alarm setpoints and to confirm scan MDCs were appropriate.

LTP Table 5-3 FR-0500-01, Revision 0 Page 2 of 20

TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 64 m2 See discussion (< 2000 mi2 )

LTP (Based on LBGR of 3.36 Number of Direct 14 pCi/g, sigma2 of 0.28 pCi/g, Measurements Required and a relative shift of 3.0.

Type I = Type 11= 0.05)

Sample Area 4.57 rn2 64 m2 / 14 = 4.57 m2 Sample Grid Spacing 2.1 m Approximately 2m x 2m Grid size < 10 m2 in Scan Grid Area (some are smaller as is accordance with Reference 4 indicated on SU maps)

Area Factor 3.8 LTP Table 6-12 Scan Survey Area 64 m2 Class I area-I 00%

Background _____X>+_____________'____________________;)__-h Average Background + DI 6-150, EC-009-01, (1000 cpm LTP Section 5 S Level 3 sigma of Background EC 009-01 (Reference 1) plus Background See Table 2-2 DCGL 4.2 pCi/g LTP Revision 3 Table 5-6 (Reference 2)

Design DCGLENIc 16.0 pCi/g DCGL x AF C. SURVEY RESULTS Fourteen direct measurements were required, 16 direct soil samples were actually obtained.

The results are presented in Table 2. All direct measurements were below the DCGL. No verified alarms resulted from scanning; therefore, no investigations needed to be performed.

2 Design sigma based on LTP Revision 3, Table 5-IC, Bailey Point, FR-0500.

FR-0500-01, Revision 0 Page 3 of 20

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

FR-0500-01-SOOI I.50E-01 + 4.59E-02 FR-0500-01-S002 9.17E-02 + 3.21E-02 FR-0500-01-S003 < 5.88E-02 FR-0500-01-S004 < 5.46E-02 FR-0500-01-S005 < 7.23E-02 FR-0500-01-S006 < 6.90E-02 FR-0500-01-S007 < 5.17E-02 FR-0500-01-S008 9.44E-02 + 3.23E-02 FR-0500-01-S009 5.54E-02 + 2.79E-02 FR-0500-01-SOIO < 5.81E-02 FR-0500-01-SO I < 4.44E-02 FR-0500-01-S012 < 4.94E-02 FR-0500-01-S013 < 5.6513-02 FR-0500-01-S014 < 4.4213-02 FR-0500-01-S015 < 5.1513-02 FR-0500:01-S16 < 4.7313-02 Mean 6.56E-02 Median 5.60E-02 Standard Deviation 2.71E-02 Range 4.42E 1.50E-01 NOTES

1. The samples were also evaluated for Co-60, all were below the nominal MDA of 0.1 pCi/g.

2. "<" indicates values less than MDA, the MDA value is reported.

D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No investigations were required.

FR-0500-01, Revision 0 Page 4 of 20

E. SURVEY UNIT DATA ASSESSMENT An analysis of the direct sample results, including the mean, median, standard deviation, and sample result range, are provided in Table 2. Both the mean and the median activities were less than the DCGL. Four of the samples had positive indications of Cs-137 at environmental levels. The maximum direct measurement result was less than 3.6 percent of the DCGL.

One background location sample contained a trace level of colbalt-60. This was corrected by subtracting the activity equivalent in cpm from the background value used to calculate the scan setpoint. This amounted to a 15 cpm reduction in background.

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 (0.07 pCi/g). The result is a net activity value of-0.12 pCi/g. This would equate to an annual dose rate of 0.0 mrem/y.3 However, for 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 (Table 1) 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 I survey unit. All of the measurements are well below the DCGL of 4.2 pCi/g.

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

FR-0500-01, Revision 0 Page 5 of 20

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 one outlier.

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 the data quality objectives were met.

G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON THE EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class I 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.

H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit I was designed, performed and evaluated in mid 2004. The design was performed to the criteria of the LTP, Revision 3 (Reference 3). No subsequent LTP changes Nwith potential impact to this survey unit needed to be evaluated.

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

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 one outlier.

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 no verified alarms, therefore no investigations were required.

It is concluded that FR-0500 Survey Unit 1 meets the release criteria of 10CFR20.1402 and the State of Maine enhanced criteria.

FR-0500-01, Revision 0 Page 6 of 20

J. REFERENCES

1. Maine Yankee Engineering Calculation, EC-009-01

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

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

4. Maine Yankee letter to NRC, MN-03-009, February 6,2003

5. Approach for Dealing wvith Background Radioactivity for Maine Yankee Final Status Surveys, Attachment E to Maine Yankee Procedure PMP 6.7.8. FSS Data Processing and Reporting FR-0500-0 1, Revision 0 Page 7 of 20

Attachment 1 Survey Unit Maps FR-0500-01, Revision 0 Page 8 of 20

Maine Yankee Alaine Yankee DecomnPissioningProjectSrey Fortu Map ID#: FR 0500 SITE Decommissioning Team Iciissoii Ire Re vised: 4-08-04 Survey Type: El Characterization Ol Turnover

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Maine Yankee a Map ID #: FR 0500-01a Decommissioning Team Mailie Yankee lecoinmissioningProject Sre Form Revised: 4/15/04 Survey Type: O3 Characterization O Turnover

• Final Status Survey I Survey Area Name: Bailey Point - Survey Unit 1 Final Status Survey FR 0500: Bailey Point (Survey Unit 1)

Survey Scan Grids: # S001 - S025 8.00m fR2L S022 S023 S024 S025I I I S 20 SI019 SIOI-R SV)17 Soll

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Maine Yankee . Map ID #: FR 0500-01c Decommissioning Team MIaiate Yantkee DecoinunissioningProjectSurvey Formi Revised: 5/11/04 Survey Type: El Characterization O Turnover

• Final Status Survey Survey Area Name: Bailey Point - Survey Unit I Final Status Survey FR 0500: Bailey Point, SUI Direct Point Locations S001 - S016 XI I I

_ S016 S015 _ I S014 $013 r I I 2.1Gm I I IS009 S10 Sol1_ 4012

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_ _ _ _ _ _I_ II I LOO1.0M 2.10m-- 2.l0m 2.10m Origin 0,0 FR-0500-01, Revision 0 Page 12 of 20 GTS Location at ME State Coordinate 406950.4305N, 624178.6831 E (West Zone)

Bailey Point totals approximately 14,400 sq-m (3.5 ac) N = 14, L = 2.1

Attachment 2 Survey Unit Instrumentation FR-0500-01, Revision 0 Page 13 of 20

TABLE 2-1 INSTRUMENT INFORMATION E-600 S/N I Probe S/N (type) 2489 725890 (SPA-3) 2490 726560 (SPA-3) 2620 H 726560 (SPA-3)

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

FSS-1 1 0.04 - 0.10 I;SS-2 1 0.04 - 0.10 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Detector SPA-3 Comments Scan MDC 5.9 Design Scan MDC, LTP Table 5-6 (pCi/g) (Reference 2)

DCGL Approved DCGL for land areas DC 4.2 outside the Restricted Area, LTP (pi/g)_ Section 6.7 (Reference 2)

Investigation Level 3 sigma of Background (Alarmn Setpoint) 12,700 plus Background cpm FR-0500-01, Revision 0 Page 14 of 20

Attachment 3 Investigation Table (None Required)

FR-0500-0 1, Revision 0 Page 15 of 20

Attachmcnt 4 Statistical Data FR-0500-01, Revision 0 Page 16 of 20

Survey Package FRO500 Unit I Soil Sign Test Summary 9.5~',3t,~-;< faluation Irtu-aus '*' ,8' -rn o> s-  ?

Survey Package: FRO500 Bailey Point Class 1 Area Survey Unit: 01 Evaluator: DR DCGL,: 4.20E+00 DCGLerc: 1.60E+01 LBGR: 3.36E+00 Sigma: 2.80E-01 Type I error: 0.05 Type II error: 0.05 Nuclide: CS-137 Soil Type: N/A Callad ommon~~

Zl,: 1.645 ZI.P:1.645 Sign p: 0.99865 Calculated Relative Shift: 3.0 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift is >3 N-Value: 11 N-Value+20%: 14 Number of Samples: 16 Median: 5.60E-02 Mean: 6.56E-02 Net Sample Standard Deviation: 2.71 E-02 Total Standard Deviation: 2.71E-02 SRSS Maximum: . 1.50E-01

.f. H, .R $^gigTestesult, Ad<,i, -iti'A -"Cm ts, Adjusted N Value

- 16 S+ Value: - 16 Critical Value: 11 Sign test results:, Pass Sufficient samples collected: Pass Maximum value <DCGLw: Pass Median value <DCGL,: Pass Mean value <DCGL,: Pass Maximum value <DCGLem: Pass Total Standard Deviation <=Sigma: - Pass Criteria comparison results: Pass The survey unit passes all conditions: :' .Pass FRO500-SU1-SoilSign 1217/04 7:04 PM FR-0500-01, Revision 0 Page 17 of 20

FR-0500 SU-1 Quantile Plot 0.16 0.14 0.12 C

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One-Sample T-Test Report Page/Date/Time 2 11/22/04 10:51:25AM Database Variable C2 Plots Section Histogram of FR-0500, SU-1 12.000*

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.040 0.070 0v.1o0 v.1t3 U.Ibu Activity (pCVg)

FR-0500-01, Revision 0 Page 19 of 20

One-Sample T-Test Power Analysis Page/Date/Time 2 11/22/04 10:52:37 AM Chart Section Retrospective Power Curve 1.0- .--- -

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Survey Unit Mean (pCi/g)

FR-0500-01, Revision 0 Page 20 of 20