ML051750702
| ML051750702 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 06/13/2005 |
| From: | Olsen C Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FR-0200-05, Rev 0 | |
| Download: ML051750702 (21) | |
Text
{{#Wiki_filter:MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0200 YARD EAST SURVEY UNIT 5 Prepared By: _/ Date:___ ____. FCSS ceri-Signature Printed Name Reviewed By: Date: G LaoS FSS Sp"lilgnature ai4dR(- (oule Printed Name Reviewved By: ( V Date: IJUH 0 9 2005 Independent Review - Signature Approved By: < Date: £X3os
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MAINE YANKEE FINAL STATUS SURVE Y RELEASE RECORD FR-0200 YARD EAST SURVEY UNIT 5 A. SURVEY UNIT DESCRIPTION FR-0200 Yard East Survey Unit 5 was located in the southeast corner of the site, partially residing in the former "Industrial Area" yard and partially in the Turbine Building Footprint. The 1445 m2 area was bordered on the north by FR-0200 Survey Unit 8, on the west by FR-01 II Survey Unit 19, on the south by FR-0200 Survey Units 4 and 9, and on the east by FR-0200 Survey Unit 2. As shown on map FRO200-5 SITE, this survey unit is approximately centered by the coordinates 624,140E and 407,600N 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 11 survey units is shown on map FR0200-5 REF (Attachment 1). The survey unit is located within the expanded Restricted Area boundary. Survey Unit 5 is a relatively flat area composed primarily of soil and backfill. B. SURVEY UNIT DESIGN INFORMATION Survey Unit 5 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 52 locations which are illustrated on map FRO200-5b (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 1445 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-m2 fields of view. The ISOCS detector was positioned perpendicular to the surface. Locations of the 76 survey scans are shown on map FRO200-5a and 5c (Attachment 1). The ISOCS scans were configured to ensure 100% scan coverage of all exposed surfaces within Survey Unit 5. 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 DCGLENIC. 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-0200-05, Revision 0 Page 2 of 21
TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 1445 m2 Class 1, < 2,000 m2 Based on an LBGR of 2.1 pCi/g, Number of Direct . sigma' of 1.33 pCi/g, and a relative Measuembents Requ18 (40 used for design) shift of 1.5, 18 were required, Measurements Required band 552 obtained. l__ Type I = Type I = 0.05. Sample Area 36m 2 1445 m 2 /40=36 m 2 Sample Grid Spacing 6.0 m (36)12 Scan Grid Area ISOCS scan at 3 meters See Section B Area Factor 1.6 Class 1 Area, LTP Table 6-12 Scan Area 1445 m2 Class I Area- 100% ISOCS investigation levels with Scan Investigation Level 1.0 pCi/g Cso-6 detector at 3-meter height
~i/g 0.36 o-60(Reference 3).
DCGL4.2 pCi/g Cs-137 DCGL applied to land outside the 1.5 pCi/g Co-60 Restricted Area. (Reference 1) 6.9 pCi/g Cs-137 DCGL x Area Factor for Class 1 Design DCGLENIC 2.5 pCi/g Co-60 survey unit, per LTP Section 5.6.3 C. SURVEY RESULTS A total of 52 direct measurements were performed in Survey Unit 5. Three samples contained detectable Cs-137 with levels of activity greater than the MDA but below the DCGL. Three samples 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 76 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 including S028, the only scan measurement to identify Co-60 (0.20 pCi/g). Therefore, no investigation surveys were performed as a result bf the scan surveys. LTP Revision 4, Table 5-IC for RCA Yard West, ROIOO (conservative). FR-0200-05, Revision 0 Page 3 of 21
TABLE 2 DIRECT MEASUREMENTS Sample Number Cs-137 Uncertainty Co-60 Uncertainty Unitized Value (pCi/g) (pCi/g) (pCi/g) (pCi/g) _________Value FR0200051SO01 < 4.22E-02 < 4.92E-02 4.28E-02 FR0200051S002 < 4.111E-02 < 4.44E-02 3.94E-02 FR020005IS003 < 3.90E-02 < 3.71E-02 3.40E-02 FR0200051S004 < 5.08E-02 < 5.42E-02 4.82E-02 FR0200051S005 < 4.81E-02 < 4.86E-02 4.39E-02 FR0200051S006 < 5.26E-02 < 5.1813-02 4.71E-02 FR0200051S007 < 4.78E-02 < 5.51 E-02 4.81E-02 FR020005 1S008 1.09E-01 2.91E-02 1.24E-01 3.59E-02 1.08E-01 FRO200051SOO9 < 5.88E-02 < 6.42E-02 5.68E-02 FR0200051SO10 < 5.97E-02 < 6.26E-02 5.59E-02 FRO200051SOI I < 4.68E-02 < 5.22E-02 4.59E-02 FRO200051SO12 < 4.80E-02 < 4.85E-02 4.3813-02 FR0200051S013 < 5.43E-02 < 5.4213-02 4.91E-02 FRO200051S014 < 4.20E-02 < 3.94E-02 3.63E-02 FRO200051S015 < 5.01E-02 < 4.96E-02 4.50E-02 FRO200051SO16 1.09E-01 2.71E-02 < 5.30E-02 6.13E-02 FR020005 1S017 < 4.80E-02 < 4.73E-02 4.3013-02 FRO200051SO]8 < 4.69E-02 < 5.07E-02 4.50E-02 FRO200051SOI9 < 4.09E-02 < 4.311E-02 3.85E-02 FRO200051S020 < 5.32E-02 < 6.35E-02 5.50E-02 FR0200051S021 < 4.82E-02 < 5.9413-02 5.111E-02 FR0200051S022 < 5.75E-02 < 7.27E-02 6.22E-02 FR0200051S023 < 4.26E-02 < 4.50E-02 4.01E-02 FR020005 1S024 < 5.211E-02 2.37E101 3.34E-02 1.70E-01 FR0200051S025 1.44E-01 3.58E-02 < 7.92E-02 8.72E-02 FR0200051S026 < 4.911E-02 < 4.9213-02 4.45E-02 FR0200051S027 < 3.99E-02 < 4.80E-02 4.15E-02 FR020005 1S028 < 6.49E-02 < 7.40E-02 6.48E-02 FR0200051S029 < 4.2213-02 < 4.59E-02 4.06E-02 FR0200051S030 < 4.33E-02 < 4.59E-02 4.09E-02 FR0200051S031 < 5.53E-02 < 6.66E-02 5.76E-02 FRO20005 1S032 < 5.40E-02 < 6.39E-02 5.55E-02 FR020005 1S033 < 5.23E-02 < 5.58E-02 4.97E-02 FR0200051S034 < 3.99E-02 < 4.84E-02 4.18E-02 FR0200051S035 < 4.58E-02 < 5.16E-02 4.53E-02 FR0200051S036 < 3.48E-02 < 4.311E-02 3.70E-02 FR0200051S037 < 3.96E-02 < 4.50E-02 3.94E-02 FR0200051S038 < 3.90E-02 < 4.50E-02 3.93E-02 FR0200051S039 < 5.01E-02 < 5.49E-02 4.85E-02 FR0200051S040 < 4.82E-02 < 4.93E-02 4.43E-02 FR-0200-05, Revision 0 Page 4 of21
FR0200051S041 < 5.01E-02 3.93E-01 3.92E-02 2.74E-Ol FR0200051S042 < 3.72E-02 < 3.811E-02 3.43E-02 FR0200051S043 < 3.99E-02 < 4.08E-02 3.67E-02 FR0200051S044 < 4.39E-02 < 5.04E-02 4.4 11E-02 FR0200051S045 < 3.90E-02 < 4.47E-02 3.91E-02 FR0200051S046 < 5.05E-02 < 5.21 E-02 4.6813-02 FR0200051S047 < 4.09E-02 < 4.47E-02 3.95E-02 FR0200051S048 < 6.1813-02 < 5.94E-02 5.4313-02 FR0200051S049 < 5.58E-02 < 5.97E-02 5.3 1E-02 FR0200051S050 < 5.36E-02 < 6.08E-02 5.33E-02 FRO200051SO51 < 4.49E-02 < 5.32E-02 4.62E-02 FRO200051SO52 < 5.23E-02 < 5.44E-02 4.87E-02 Mean 5.1913-02 6.39E-02 5.50E-02 Median 4.8213-02 5.17E-02 4.56E-02 Standard Deviation 1.89E-02 5.47E-02 3.74E-02 Range 3.4813-02 to 1.44E-01 3.7 1E-02 to 3.931E-01 3.4013-02 to 2.7413-01
"<" indicates MDA value. Bold indicates positive detection value.
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 52 soil samples collected, three identified Cs-137 activity below the DCGL value of 4.2 pCi/g and three samples identified Co-60 activity below the DCGL value of 1.5 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 ofthe unity measurements was 0.055 indicating that the direct measurements averaged 5.5% 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 (0.052 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 0.43 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. 2 See Attachment E to Maine Yankee Procedure PMP 6.7.8 (Reference 2). 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 1.5 pCilg outside the RA and the mean Co-60 direct activity value of 0.064 pCi/g) would equate (-0)64 Y to Annual Dose Rate =1lx 0.43 rnren ly. FR-0200-05, Revision 0 Page 5 of 21
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. 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. 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-I 37) and 1.5 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 1 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. FR-0200-05, Revision 0 Page 6 of 21
Il. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 5 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-I 37 and 1.5 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. 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 at a distance of 3 meters 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 were required as a result of the scan process. It is concluded that FR-0200 Survey Unit 5 meets the release criteria of 10CFR20.1402 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-0200-05, Revision 0 Page 7 of 21
Attachment 1 Survey Unit Maps FR-0200-05, Revision 0 Page 8 of 21
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Maine Yankee IMap ID#:FRO200-5 REF Decommissioning Team IAaite Yankee DecommissioningProjectSurveys Forl Date: 5/24/05 Survey Type: l Characterization 0 Turnover 9 Final Status Survey Survey Area Name: Yard East Final Status Survey FRO200 SU5 Reference Map __ X1 ) . \I FR-0200-05, Revision 0 Page 10 of 21 FRO200 SU5 Total Survey Unit Area = 1445 sq-m
Maine Yankee i . . . . F Map ID#: FRO200-5a Decommissioning Team Maie Yankee Decom nssionng ProjectSurvey Form IDate: 6/7/05 Survey Type: a Characterization 0 Turnover X Final Status Survey Survey Area Name: Yard East Final Status Survey FRO200 SU5: Yard East ISOCS Scans S001 - S072, S074 - S076
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FR-0200-05, Revision 0 ISOCS I 624,018.2 E Page 11 of 21 Start Point 407,588. 7N Surface Area = 1445 sq-m
Maine Yankee Yk D ProjecF Mapaine ID#:FRO200-5b DecommissioningTeam Iazee econiiissioningr urej'Forin ate: 4128105 Survey Type: l Characterization E Turnover X Final Status Survey lSurvey Area Name: Yard East Final Status Survey FRO200 SU5: Yard East Direct Points SOO1 - S052 FR-0200-05, Revision 0 Page 12 of 21 624,018.2 E 407,588. 7N Surface Surface Area Area == 1445 1445 sq-msq-rn N N40= 40 L= 6.Om L=6.Om
Maine Yankee I . . . . . Map ID#: FRO200-5c Decommissioning Team Yankee Decommissionin Project Survey Form IMane Date: 6/2/05 Survey Type: O Characterization El Turnover 9 Final Status Survey iSurvey Area Name: Yard East Final Status Survey FRO200 SU5: Yard East ISOCS Scan S073 407,536.1 N FR-0200-05, Revision 0 Page 13 of 21 624,018.2 E Surface Area = 1445 sq-m 407,588.7N
Attachment 2 Survcy Unit Instrumentation FR-0200-05, Revision 0 Page 14 of 21
TABLE 2-1 INSTRUMENT INFORMATION ISOCS Detectors (Field Measurements) Detector No. MDC (pCi/g) 7607 0.15 to 0.35 7722 0.15 to 0.30 7780 0.11 to 0.29 HIPGe Detectors (Laboratory Analysis) Detector No. MDC (pCi/g) FSS2 0.04 to 0.07 FSS2 0.03 to 0.08 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL AND DCGLEAIC Parameter Instrument: ISOCS Comments Scan MDC 0.13 to 0.35 pCi/g Cs-137 16% DCGL 0.11I to 0.24 pCi/g Co-60 Approved DCGL for land DCGL 4.2 pCi/g Cs-137 areas outside the Restricted 1.5 pCilg Co-60 Area (Reference 1) Investigation Level 1.0 pCi/g Cs-137 f 3 (ISOCS ( 3 m) 0.36 pCi/g Co-60 (Reference ) 6.9 pCi/g Cs-137 DCGL x Area Factor for Design DCGLENIC 2.5 pCi/g Co-60 Class I survey unit, per LTP 2.5 pilg o-60Section 5.6.3 FR-0200-05, Revision 0 Page 15 of 21
Attachment 3 Investigation Table (No Investigations Required) FR-0200-05, Revision 0 Page 16 of 21
Attachment 4 Statistical Data FR-0200-05, Revision 0 Page 17 of 21
Survey Package FRO200 Unit 5 UNITY Soil Sign Test Summary Survey Package: FRO200 Survey Unit: 05 Evaluator: Andy Olsen DCGL,: 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 __ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1 C n m ents K Z,.-: 1.645 Z1-p .' .645 Sign p: ' '0.933193 Calculated Relative Shift: r 1.5 Relative Shift Used: 7 1.5Uses 3.0 if Relative Shift is >3 N-Value: ; 15 N-Value+20%: 18
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,,,,Z' Number of Samples: - 52 Median: 4.56E-02 Mean: ,-;:5.50E-02 Net Sample Standard Deviation: .7 ' -3.74E-02_
Total Standard Deviation: : ' "3.74E-02 Sum of samples and reference Maximum: 2.74E-01
,,,, >'.-.,SigrnTest Results -,4" e :'y , .- Commen s Adjusted N Value: l52 S+ Value: ' ' -52 Critical Value: -, ' , 32 Sign test results: ' -^'-Pass Co-mens'
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Sufficient samples collected:. . ,Pass Maximum value <DCGLw: __ _ ___ _;Pass Median value <DCGLw: *Pass Mean value <DCGL,: -'Pass Maximum value <DCGLen,: Pass Total Standard Deviation <=Sigma: 'Pass Criteria comparison results: iPass The . ua-i-a tp-as di - 'i ss e . .o';- '. -P-
-iin The survey unit passes all conditions:l - '- '- Pass Survey Unit Passes FRO200-SU5-SoilSign-UNITY.xls FR-0200-05, Revision 0 6/6105 4:11 PM Page 18 of 21
FRO200 SU-5 Quantile Plot 0.3 0.25 N_ N 11 0.2
- Activity (unitized) w 0 CD0
- 0.15 DC C. -Median (unitized)
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One-Sample T-Test Report Page/Date/Time 2 6/6/05 10:29:00 AM Database Variable C2 Plots Section Histogram of FR-0200, SU-5 50 c, 38 a. E o 25-C)
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0.000 0 0.075 . .1 s o. 225 0.300 Activity (unitized) FR-0200-05, Revision 0 Page 20 of 21
One-Sample T-Test Power Analysis Page/Date/Time 2 616105 10:29:56 AM Chart Section Retrospective Power Curve I\ , I I I 9 I I I I I I I Il I I I X I 0.8 - I I, - I \ I I I I I I I I 9 I , , I I I
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I I I I I I I I I 0.0 - I I I I 0.0 0'2 0'4 0'6 0:8 1.0 Survey Unit Mean (unitized) FR-0200-05, Revision 0 Page 21 of 21}}