ML051750708

to Maine Yankee Final Status Survey Release Record FR-0200 Yard East Survey Unit 8.

ML051750708
Person / Time
Site:	Maine Yankee
Issue date:	06/16/2005
From:	Olsen C Maine Yankee Atomic Power Co
To:	NRC/FSME
References
FR-0200-08, Rev 0
Download: ML051750708 (22)

Text

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0200 YARD EAST SURVEY UNIT 8 Prepared By: Date: vgane avr F Sngini cr- ignature Printed Name Reviewed By: Hi Date: 6bf losI Scce Rcvi- Signature ritd Name Reviewed By: <DaIuJUM 11 6 M051 Inde endent Review - Signature anltcntc Approved By: Date:

-nndnt M7tgature 4Printed Namne/

Approved By: X e Date: M S, MoP - Signature

.~R. 2. 3 c Printed Name Revision 0

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0200 YARD EAST SURVEY UNIT 8 A. SURVEY UNIT DESCRIPTION FR-0200 Yard East Survey Unit 8 was located in the SE corner of the site, partially residing in the former "Industrial Area" yard and partially residing in the Turbine Building Footprint.

The 1,585 mr area was bordered on the north by FR-0200 Survey Units 6 and 7, on the west by FR-01 11 Survey Units 19 and 20, on the south by FR-200 Survey Unit 5, and on the east by FR-0200 Survey Unit 2. As shown on map FRO200-8 SITE, this survey unit is approximately centered by the coordinates 624,160E and 407,655N using the Maine State Coordinate System (West Zone) NAD 1927. The location of the survey unit in relation to the Service Building and the surrounding FR-0200 and FR-01 I1 survey units is shown on map FRO200-8 REF (Attachment 1). The survey unit is located within the expanded Restricted Area boundary.

Survey Unit 8 is an area composed primarily of soil and backfill with a small amount of concrete structural remnants.

B. SURVEY UNIT DESIGN INFORMATION Survey Unit 8 was originally classified, per the LTP Revision 4, as a Class 3 survey unit, but was reclassified to Class 1 given its history during decommissioning activities.

The survey unit design parameters are shown in Table 1. Given a relative shift of 1.5, eighteen direct measurements would be required for the Sign Test, but 40 were prescribed as a conservative measure. Because the measurement locations were based on a systematic square grid with a random start point, the N=40 design led to a survey unit map with 48 locations which are illustrated on map FRO200-8b (Attachment 1). Direct measurements (soil samples) were collected from required locations and analyzed with laboratory gamma spectroscopy instrumentation.

In accordance with the LTP, scans covering 100% of the 1585 m2 area were required for the Class 1 survey unit. This was accomplished by use of an in situ gamma spectroscopy detector (ISOCS) configured at a 3-meter distance from the surface to obtain overlapping 28-in 2 fields of view for 109 of the 113 shots. For locations C084 and C085 located under a concrete shelf, the ISOCS detector employed a 2m distance. For locations Cl10 and ClIl which were scans of concrete crevices, a nominal 0.7m distance was used. The ISOCS detector was positioned perpendicular to the surface. Locations of the 113 survey scans are shown on maps FR0200-8a, 8c and 8d (Attachment 1).

The ISOCS scans were configured to ensure 100% scan coverage of all exposed surfaces within Survey Unit 8. The survey instruments used are listed by model and serial number in Attachment 2 (Table 2-1). Scan MDCs are also listed in Attachment 2 (Table 2-2) and are compared to the DCGL, the investigation level, and the DCGLEMlc. The scan MDC is less than the scan investigation level, thus providing high confidence (95% or higher) that an elevated area would be detected in the scanning process. Furthermore, since the investigation level was always less than the design DCGLEMC, no EMC sample size adjustment was necessary.

FR-0200-08, Revision 0 Page 2 of 22

TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 1585 m2 Class 1, < 2,000 m2 Based on an LBGR of 2.1 Number of Direct pCi/g, sigma' of 1.33 pCi/g, Measurements Required 18 (40 used for design) and a relative shift of 1.5, 18 were required, 48 obtained.

Type I = Type II = 0.05 Sample Area 40 2 m 1585 m 2 40 40 4m2 Sample Grid Spacing 6.2 m (40)

Scan Grid Area ISOCS scan at 3, 2, and 0.7 See Section B meters Area Factor 1.6 Class I Area, Area_Factor_ 1.6LTP Table 6-12 Scan Area 1585 M2 Class 1 Area- 100%

. . 1.0 pCi/g Cs-137 ISOCS investigation levels Scan Investigation Level 0.36 pCi/g Co-60 (Reference 3)

DCGL applied to land DCGL 4.2 pCi/g Cs 137 outside the Restricted Area 1.52 pCi/g Co-60 (Reference 1) 6.7 pCi/g Cs 137 DCGL x Area Factor for Design DCGLENIC 264 pCifg Cos63 Class 1 survey unit, per LTP 2.4o-60Section pifg 5.6.3 C. SURVEY RESULTS A total of 48 direct measurements were performed in Survey Unit 8. Two samples contained detectable Cs-137 with levels of activity greater than the MDA but below the DCGL. One sample contained detectable Co-60 activity above the MDA but below the DCGL. All other measurements were below the MDA. The results are presented in Table 2. No investigations were necessary as a result of the direct measurements.

ISOCS gamma scans were performed at 113 locations using an investigation level of 1.0 pCi/g Cs-137 and 0.36 pCi/g Co-60. The gamma scans were performed for a sufficient count time to achieve a Minimum Detectable Activity (MDA) of approximately 16% of the DCGL.

All identified scan activity levels and MDAs were below the investigation levels. Therefore, no investigation surveys were performed as a result of the scan surveys.

LTP Revision 4, Table 5-iC for RCA Yard West, ROI00 (conservative).

FR-0200-08, Revision 0 Page 3 of 22

TABLE 2 DIRECT MEAS UREMENTS Sample Number Cs-137 Uncertainty Co-60 Uncertainty Unitized Value (pCi/g) (Ci!g) __(pCi/g) (pCi/g)

FRO200081SO01 < 5.22E-02 _< I5.56E-02 _ __ 4.90E-02 FR0200081S002 < 4.91E-02 j< I5.63E-02 4.87E-02 FR0200081S003 1.18E-01 3.26E-02 < 6.56E-02 7.12E-02 FR0200081S004 < 3.77E-02 < 4.22E-02 3.67E-02 FRO200081S005 < 5.17E-02 < 5.9513-02 5.1SE-02 FR0200081S006 < 4.3913-02 < 4.24E-02 _ _ 3.83E-02 FR0200081S007 < 4.32E-02 < 4.39E-02 3.92E-02 FR0200081S008 < 4.03E-02 < 6.60E-02 5.30E-02 FR0200081S009 6.76E-02 3.20E-02 < 7.21E-02 6.35E-02 FRO200081SO1O < 4.06E-02 < 4.14E-02 3.69E-02 FR0200081SSO I < 4.75E-02 < 6.75E-02 5.57E-02 FR0200081S012 < 4.60E-02 < 5.1OE-02 4.4513-02 FR0200081S013 < 5.39E-02 < 5.43E-02 4.86E-02 FR0200081S014 < 4.74E-02 2.19E-01 2.97E-02 1.55E-01 FR0200081S015 < 4.1OE-02 < 4.21 E-02 3.75E-02 FR0200081S016 < 3.96E-02 < 4.66E-02 4.01 E-02 FR0200081S017 < 4.02E-02 < 4.92E-02 4.19E-02 FR0200081S018 < 4.80E-02 < 5.2813-02 4.62E-02 FR0200081SO19 < 4.68E-02 < 5.31 -02 4.61E-02 FR0200081S020 < 5.111E-02 < 5.29E-02 4.70E-02 FR0200081S021 < 4.36E-02 < 5.011E-02 4.33E-02 FR0200081S022 < 4.30E-02 < 5.20E-02 4.44E-02 FR0200081S023 < 6.22E-02 =____< 5.70E-02 5.23E-02 FR0200081S024 < 5.02E-02 < 5.43E-02 4.77E-02 FR0200081S025 < 5.26E-02 < 6.59E-02 5.5913-02 FR0200081S026 < 4.43E-02 < 4.68E-02 4.13E-02 FR0200081S027 < 4.47E-02 < 4.74E-02 4.18E-02 FR0200081S028 < 5.311E-02 < 5.38E-02 4.80E-02 FR0200081S029 < 3.43E-02 < 3.68E-02 3.24E-02 FR0200081S030 < 5.311E-02 < 5.15E-02 4.65E-02 FR0200081S031 < 5.08E-02 < 5.11E-02 1 4.57E-02 FR0200081S032 < 4.211E-02 < 4.61E-02 4.04E-02 FR0200081S033 < 3.73E-02 < 4.25E-02 3.68E-02 FR0200081S034 < 4.52E-02 < 4.38E-02 3.96E-02 FR0200081S035 < 3.86E-02 < 4.4613-02 3.85E-02 FR0200081S036 < 5.42E-02 < 5.11E-02 4.65E-02 FRO200081S037 < 3.82E-02 < 4.44E-02 _ 3.83E-02 FR0200081S038 < 4.27E-02 < 5.111E-02 4.381E-02 FR0200081S039 < 4.051E-02 _ 4.731E-02 4.08E-02 FR0200081S040 1<- 4.54E-02 i 4.62E-02 4.12E-02 FR0200081S041 < 4.74E-02 < 5.1613-02 _ _ 4.52E-02 FR0200081S042 < 3.73E-02 < 4.02E-02 3.53E-02 FR0200081S043 < 5.07E-02 < 5.62E-02 4.9013-02 FR0200081S044 < 4.08E-02 < 4.73E-02 4.08E-02 FR0200081SO45 < 5.00E-02 < 5.331E-02 4.70E-02 FR0200081S046 < 4.1SE-02 < 4.88E-02 4.20E-02 FR0200081S047 < 5.311E-02 < 5.98E-02 5.203E-02 FR0200081S048 < 5.03E-02 < 6.19E-02 5.27E-02 Mean 4.78E-02 = 5.49E-02 4.75E-02 Median 4.57E-02 5.1 1E-02 4.49E-02 Standard Deviation 1.23E-02 2.54E-02 1.74E-02 Range 3.431E-02 to 1.1 8E-01 3.68I3-02to2.199E-01 3.2413-02 to 1.55E-01

"<" indicates MDA value. Bold indicates positive detection value FR-0200-08, Revision 0 Page 4 of 22

D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS Based on the scan 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 result range, is provided in Table 2. Positively detected values are bolded in the table. Of the 48 soil samples collected, two identified Cs-137 activity below the DCGL value of 4.2 pCi/g and one sample identified Co-60 activity below the DCGL value of 1.52 pCi/g. All other values were below the MDA. Identified sample activities or Minimum Detectable Activities are listed in Table 2. The mean and median activities were less than the DCGLs for Cs-137 and Co-60. The average of the unity measurements was 0.048 indicating that the direct measurements averaged 4.8% of the DCGL limit.

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 mean fallout Cs-137 value (0.19 pCi/g) 2 for disturbed soil from the survey unit sample mean activity (0.048 pCi/g). This would equate to an annual dose rate of 0.0 mrem/year.

Taking into account the average residual contamination for Co-60, the annual dose rate would equate to 0.36 mrem/yr. Also, for purposes of demonstrating compliance with the radiological criteria for license termination and the enhanced State of Maine criteria, background activity was not subtracted from the 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 wvell as a listing of the key release criteria. The direct measurements clearly pass the Sign Test. The subject release criteria have been satisfied. In addition, the sample standard deviation is smaller than the design sigma; therefore, no additional samples were required.

2 See Attachment E to Maine Yankee Procedure PMP 6.7.8 (Reference 2).

3 This annual dose is based on LTP Section 6.7, which shows the contaminated soil contribution (for soils contaminated at the DCGL) to be 10 mrem/y. Therefore, the annual Co-60 dose rate (using the Co-60 DCGL of 1.52 pCi/g outside the RA and the mean Co-60 direct activity value of 0.055 pCi/g) would equate to AnnualDoseRate=10 x J= 0.36mremry.

FR-0200-08, Revision 0 Page 5 of 22

2. The Quantile Plot was generated from the unity data listed in Table 2. The data set and plot are consistent with expectations for a Class 1 survey unit. All of the measurements are below the DCGLs of 4.2 pCi/g (Cs-1 37) and 1.52 pCi/g (Co-60) for land outside the Restricted Area.

3. A Histogram Plot was also developed. This plot shows 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 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 I land survey area; the FSS results were consistent with that classification. The direct measurement sample standard deviation was less than the design sigma. Thus, a sufficient number of sample measurements were taken and no additional measurements were required.

I{. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 8 was designed, performed, and evaluated in the June 2005 time frame. The design was performed to the criteria of the LTP Revision 4 (Reference 1). No subsequent LTP changes with potential impact to this survey unit need to be evaluated.

I. CONCLUSION The FSS of this survey unit was designed based on the 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 DCGLs of 4.2 pCi/g Cs-137 and 1.52 pCi/g Co-60. There were no investigations.

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.

FR-0200-08, Revision 0 Page 6 of 22

The scan survey design for this survey unit was developed in accordance with the LTP Revision 4 (Reference 1) with significant aspects of the design discussed in Section B and Table 1. ISOCS scans performed in a systematic grid pattern throughout the survey unit did not identify activity above the scan investigation levels of 1.0 pCi/g Cs-137 and 0.36 pCi/g Co-60. Therefore, no investigations wvere required as a result of the scan process.

It is concluded that FR-0200 Survey Unit 8 meets the release criteria of I OCFR20. 1402 and the State of Maine enhanced criteria.

J. REFERENCES

1. Maine Yankee License Termination Plan, Revision 4, February 28, 2005 provided by Maine Yankee letter to the NRC, MN-05-010

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

3. Maine Yankee Calculation No. EC-003-04, Use of Canberra In Situ Object Counting System (ISOCS) for FSS Surveys FR-0200-08, Revision 0 Page 7 of 22

Attachment 1 Survey Unit Maps FR-0200-08, Revision 0 Page 8 of 22

cn 0 Cn CD 2 8 CD 0

o 0 a 0 0l 2 F:

0 0 CD %O %D 0 0

0 0 r-* Cn-O 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 *nCD Di 623,000 E 0 -- I CD 0i CD 0)

CD w oN 2 03 S ________x - 623. 500 E 0 n

C 0

CD

-624.000 E 0

-I? 03 w

0 0 U)

CD 0

624,500 E 00

. cn CD I'D oo C U) :2 t'J CD 5.

0 0.

Ci)

CD _1 2) l<

00 M

W zm 0 0

l<

B.

m o; C,)

CD0 626, 000 C Ci)

=1 mn U-4 FRO200 SU8 Note

Grid based on Maine State Coordinate System (West Zone) NAD 1927

Maine Yankee IMap ID#:FRO200-8 REF Decommissioning Team IMaine Yankee DeconzmissioningProjectSurvey Forin IDate: 5/25/05 Survey Type: ED Characterization E Turnover X Final Status Survey I Survey Area Name: Yard East Final Status Survey FRO200 SU8 Reference Map

___ \ ) *\

FR-0200-08, Revision 0 Page 10 of 22 FRO200 SU8 Total Survey Unit Area = 1585 sq-m

Maine~~~~~Maine Yankee IIAaeYneDecommissioningProjectSurvey Formi~atel~fo~~0 Yankee Map ID #: FRO200-8a Decommissioning Team i IDate: 6/7105 Survey Type: El Characterization LI Turnover 9 Final Status Survey ISurvey Area Name: Yard East Final Status Survey FRO200 SU8: Yard East ISOCS SCANS SOO1 - S083 Typical ISOCS Spacing (Maximum) 624,045.5E 407, 715.6 N-4

.47n I.:

FR-0200-08, Revision 0 Start Point Page I I of 22 Surface Area = 1585 sq-m

Maine Yankee I IMap ID#:FRO200-8b Decommissioning Team IMaiie Yanikee DecommiiissioninigProjectSin'eyForni IDate: 4(28(05 Survey Type: 0 Characterization E Turnover X Final Status Survey I Survey Area Name: Yard East Final Status Survey FRO200 SU8: Yard East Direct Points S001 - S048 624,294.3 E 407,661.9 N FR-0200-08, Revision 0 8 YP. 0.97M, Page 12 of 22 Area == 1585 Surface Area Surface 1585 sq-msq-rn N = 40 N=40 L= 6.2m L=6.2m

Maine Yankee . Map IDL: FR(

Decommissioning Team Maine Yankee Decommtissioning ProjectSurvey Foriz Date: 6/13/05 Survey Type: E Characterization E Turnover X Final Status Survey ISurvey Area Name: Yard East Final Status Survey FRO200 SU8: Yard East Trench and Depression ISOCS Scans S112 & S113 positioned 1m down slope, perpendicular to slope -1 N

1M N ez 0

Trench Scans Trench Soil Scans D = 3m Downward FR-0200-08, 0 A = 3m Angled Page 13

Maine Yankee map iUW: F-Decommissioning Team IMaine Yankee DecoinwissioningProjectSurvey Form IDate: 6/8/05 Survey Type: El Characterization O Turnover X Final Status Survey I Survey Area Name: Yard East Final Status Survey FRO200 SU8: Yard East Crevice ISOCS Scans 1111 Crevice r Align 70 ISOCS at Slice Scans FR-0200-08, Revision 0 Page 14 of 22 fO.70m Concrete

Attachment 2 Survey Unit Instrumentation FR-0200-08, Revision 0 Page 15 of 22

TABLE 2-1 INSTRUMENT INFORMATION ISOCS Detectors (Field Measurements)

Detector No. MDC (pCi/g) 7607 0.18 to 0.35 7722 0.12 to 0.29 7780 0.09 to 0.32 IIPGc Detectors (Laboratory Analysis)

Detector No. MDC (pCi/g)

FSSI 0.04 to 0.07 FSS2 0.03 to 0.07 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL AND DCGLENIC Parameter Instrument: ISOCS Comments Scan MIDC 0. I to 0.35 pCi/g Cs-137 - 16% DCGL 0.09 to 0.24 pCilg Co-60 4.2 pCifg Cs-137 Approved DCGL for land DCGL 14 pCi/gCo360 areas outside the Restricted Area (Reference 1)

Investigation Level 1.0 pCi/g Cs-137 (Refe c 3)

(ISOCS @ 0.7, 2, and 3 m) 0.36 pCi/g Co-60 eferen 3 6.7 pCi/g Cs-137 DCGL x Area Factor for Design DCGLENMc 2.4 pCi/g Co-60 Class I survey unit, per LTP 2.4 pi/g o-60Section 5.6.3 FR-0200-08, Revision 0 Page 16 of 22

Attachment 3 Investigation Table (No Investigations Required)

FR-0200-08, Revision 0 Page 17 of 22

Attachment 4 Statistical Data FR-0200-08, Revision 0 Page 18 of 22

Survey Package FRO200 Unit 8 UNITY Soil Sign Test Summary t -~i,,4-!uatu ton,nputtVai'

- u:3, - -i,T0 -t ',-.' orn n s t~>'y' .

Survey Package: FRO200 Survey Unit: 08 Evaluator: Andy Olsen DCGLw: 1.OOE+00 Unity DCGLemc: 1.60E+00 AF = 1.6 LBGR: 5.00E-01 Sigma: 3.17E-01 (1.33 pCi/g /4.2 pCi/g)

Type I error: ; - 0.05 Type II error: 0.05 Nuclide: UNITY Soil Type: N/A Z.p: . ' 1;645 Sign p: 0.933193 Calculated Relative Shift. ___________________

Relative Shift Used: 1.5 Uses 3.0 if Relative Shift is >3 N-Value: ' 15 N-Value+20%: - '18 Number of Samples: -  ;' .48 Median: - ,. 4.49E-02 Mean: '475E-02 Net Sample Standard Deviation: 1:74E-02 Total Standard Deviation: . 1.74E-02 Sum of samples and reference Maximum:  ; 1.55E-01

,-.,?,-' ignTestResult ;brne .s,;-:L,t;*-

Adjusted N Value:l.'_:___:;_'__-i S+ Value::. :.' -4 Critical Value:J. 30 Sign test results:, '";'Pass Sufficient samples collected: iPass Maximum value <DCGL, :as Median value <DCGL -: Pass Mean value <DCGLw: - ' Pass Maximum value <DCGL,-: Pass

-P Total Standard Deviation <=Sigma: : -Pass Criteria comparison results: Pass __

-, -' s 'omme.

The survey unit passes all conditions:; .' -' -,Pass Survey Unit Passes FRO200-SUB-SoilSign-UNITY.xls 6/11/05 6:58 PM FR-0200-08, Revision 0 Page 19 of 22

FRO200 SU-8 Quantile Plot 0.2 N

H_ 0.15

'1 0

• Activity (unitized)

C S 0w 600 - 0.1 CO 0 '-

t-Median (unitized) tj 50w

• 5 CI

._ 0.05

'D 0 I I I I I 0 25 50 75 100 Percent

One-Samiple T-Test Report Page/Date/Time 2 6/13/05 5:41:04 AM Database Variable C2 Plots Section Histogram of FR-0200, SU-8 0

U, E

C)

CD

.0 E

Z Activity (unitized)

FR-0200-08, Revision 0 Page 21 of 22

One-Samplej T-Test Power Analysis Page/Date/Time 2 6/13/05 5:42:07 AM Chart Section Retrospective Power Curve 1.0- .- -.-

0.8 ----- --

III I I L- II \  ;

aI) 0~

0.6-- -- -, I II

- - - -s- - - - - - - - - - -- -\ I:

s-I I I 0 .4- - -- - - - -- -- -,-- -- -- -- e---- - - -- ---

0.4-0.2 ---

-- 0_2 0_4 0-6 I I I i I(

0.o.0 0.2 0.4 0.6 0.8 1.0 Survey Unit Mean (unitized)

FR-0200-08, Revision 0 Page 22 of 22