ML050590043
| ML050590043 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/17/2005 |
| From: | Donna Anderson, Cooper W, Packer J, Pillsbury G, Tozzie R Maine Yankee Atomic Power Co |
| To: | Document Control Desk, NRC/FSME |
| References | |
| FB-1500-01, Rev 0 | |
| Download: ML050590043 (20) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-1500 WAREHOUSE 2/3 SURVEY UNIT I Prepared By: Andjho Mt Date: .1I105 FSS Engineer - Signature Printed Name Reviewed By: 2_ Date:
,_FS S ~ ature Printed Name Reviewed By: Date: 2 / 24°
'-iinependent R iew - Signature z P/intndj me Approved By: I Date: _____
,t t!Vc, FSS - Signature Printed ame Approved By: 4, , dDate: 7 MOP - Signature Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-1500 WAREHOUSE 2/3 FOOTPRINT SURVEY UNIT 1 A. SURVEY UNIT DESCRIPTION Survey Unit FB-1500-01 consisted of the sub-slab soil footprint and remaining concrete footings (3-ft. below grade) of Warehouse 2/3. The 2,550 m2 survey area was located in the western portion of the site outside of the Industrial Area. The northwest corner of the footprint is located at site coordinates 408,160N and 623,527E using the Maine State Coordinate (West Zone) NAD 1927, as shown on Map FB 1500 SITE (Attachment 1).
Warehouse 2/3 served as the main warehouse facility for the plant during Maine Yankee's operating history and for a portion of the decommissioning activities. Supplies and spare parts were both received and stored in the steel frame structure in addition to plant materials, chemicals and equipment. Although the warehouse was located outside the radiologically controlled area, four small "Restricted Areas" were established within the facility at different times throughout Maine Yankee's operational and decommissioning activities. Only one of the areas used for temporary storage of radioactive material received or awaiting shipment existed for an extended period of time. This area was also used to store contractor samples taken during characterization activities. The restricted areas were posted and periodically surveyed. A reference map of the former Warehouse facility showing the approximate locations of former Restricted Areas is shown on FB 1500-TSA (Attachment 1).
B. SURVEY UNIT DESIGN INFORMATION The survey unit was designated a Class 3 survey per the LTP (Table 5-1 B) and the 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 Map FBI500 DP REF (Attachment 1). Direct measurements (soil samples) were collected from the required locations and analyzed with laboratory gamma spectroscopy instrumentation.
In accordance with the LTP Table 5-3, gamma scans were required for I to 10% of the survey design area. Scan grids measuring 3 m by 3 m, 1.5 m by 6 m or I m by 9 m were established throughout the survey unit and E-600/SPA-3 instrumentation used to perform the scan surveys. The 30 scan grids provided a total scan area of approximately 270 in2 ,
exceeding the 10% requirement of the LTP. Configuration of the scan grids is illustrated on FB 1500-la (Attachment 1). Background values were established based on local scaler values in the survey unit. These background values were used to establish scan alarm setpoints, and to confirm the scan MDCs used were appropriate. Due to variability in scaler values within the survey unit, the grids were divided into five different background groups as provided on FB 1500-LOC.
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 and the investigation level.
FB-1500-01, Revision 0 Page 2 of 20
TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit Dcsign Critcria [ Basis Area 2,550 m2 No limit for Class 3, based on Area ,550LTP Table 5-2 Based on adjusted LBGR of 3.51 Number of Direct 14 pCi/g, sigma' of 0.23 pCi/g, and Measurements Required a 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 3 x 3 m, 1.5 x 6 m, or Class 3 Area
___ __ __ ___ __ ___ __ 1 x 9 m grids (9 in)
Area Factor N/A Class 3 Area Scan Area 270 m2, > 10% Class 3 Area- 1% to 10%
Background - ;*- ,A . ..
10,300 cpm Group A 10,600 cpm Group B SPA-3 (scan) 9,900 cpm Group C 9,500 cpm Group D 8,900 cpm Group E Scan Investigation Level 3 Sigma of Background See Table 2-2 (Attachment 2) plus Background (Reference 6)
DCGL 4.2 pCi/g Cs-137 LTP, Rev. 3, Section 6.7 Design DCGLEMc N/A Class 3 Area C. SURVEY RESULTS As required, 14 direct soil measurements were performed in Survey Unit 1 and the results are presented in Table 2. All direct measurements were below the Minimum Detectable Activities, which were well below the DCGL.
A total of 30 grids measuring approximately 9 mi2 each were scanned using E-600/SPA3 instrumentation. No verified alarms were received during the scan survey. Therefore, no investigations were required.
LTP Revision 3, Table 5-I C for Bailey House Land Area, R1800, and Foxbird Island, RI OOO, as average sigma value for disturbed soil.
FB-1500-01, Revision 0 Page 3 of 20
TABLE 2 DIRECT MEASUREMENTS Sample Location Cs-137 (pCi/g)
FB]500-01-3SOOISS <3.89E-02 FB1500-01-3S002SS <4.45E-02 FB1500-01-3SO03SS <4.41E-02 FB1500-01-3SO04SS <4.30E-02 FB1500-01-3SO05SS <5.59E-02 FB1500-01-3SO06SS <4.83E-02 FB1500-01-3SO07SS <3.72E-02 FBI500-01-3S008SS <4.39E-02 FBI500-01-3SO09SS <4.49E-02 FB1500-01-3SOIOSS <4.08E-02 FB1500-01-3SOIISS <4.48E-02 FBl500-01-3S012SS <3.49E-02 FBI500-01-3SO13SS <3.51E-02 FB1500-01-3S014SS <4.02E-02 Mean 4.26E-02 Median 4.35E-02 Standard Deviation 5.51E-03 Sample Range 3.49E-02 to 5.59E-02
"<" indicates MDA value. Samples were also analyzed for Co-60. All were less than MDA.
D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No survey unit investigations were performed.
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. Of the 14 soil samples collected, all Cs-137 values were below the Minimum Detectable Activities. The MDAs are listed in Table 2. The mean and median activities for Cs-137 were also less than the DCGL. In addition, Co-60 was not identified in any of the 14 samples.
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 (0.04 pCi/g). The net result is negative and would equate to an annual dose rate of 0.0 mrem/year. However, for purposes of demonstrating compliance -withthe radiological criteria for license termination and the enhanced State criteria, background activity was not subtracted from the soil sample analysis activity values.
2 See Attachment E to Maine Yankee Procedure PMP 6.7.8 (Reference 5).
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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.
I. 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. The sample standard deviation is smaller than the design sigma; therefore no additional samples were required.
- 2. The Quantile Plot was generated from the 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 4.20 pCi/g for land outside the restricted area.
- 3. A Histogram Plot was also developed based on the direct measurement data values. This plot shows a normal distribution.
- 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 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.
FB-1500-01, Revision 0 Page 5 of 20
II. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit I was designed, performed, and evaluated in the January 2005 time frame. The design was performed to the criteria of the LTP Revision 3 (References 2 and 4).
The only subsequent LTP change modified the Table 6-11 "Contaminated Material DCGL" to reflect an increased Deep Soil DCGL for Co-60 inside the Restricted Area. However, the Deep Soil DCGL change does not apply to this survey unit as the surface soil DCGL for areas outside the restricted area remained unchanged. 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 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 4.20 pCi/g Cs-137.
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 normal distribution.
The scan survey design for this survey unit was developed in accordance with the LTP Revision 3 Addenda (References 2 and 4) with significant aspects of the design discussed in Section B and Table 1. Scans performed using E-600/SPA-3 instrumentation did not result in any verified alarms.
It is concluded that FB 1500 Survey Unit I meets the release criteria of I OCFR20.1402 and the State of Maine enhanced criteria.
J. REFERENCES
- 1. Maine Yankee License Termination Plan, Revision 3, October 15,2002 and Addenda provided by Maine Yankee letter to the NRC, MN-02-061, 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 (LTP Supplement to LTP Revision 3)
- 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. Maine Yankee Calculation No. EC 009-01 (MY), Instrumentation Selection and MDC Calculation FB-1500-01, Revision 0 Page 6 of 20
Attachment 1 Survey Unit Maps FB-1500-01, Revision 0 Page 7 of 20
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I Main Yakee anke I~con Mane ~sn PrI S~ F Mapp ID#: FBI1500-TSA issioningProjectsSu y Formn TRe vised: 2-07-05 Yankee DeconnlAlaine Decommissioning Team Survey Type: 0 Characterization 0 Turnover U Final Status Survey i Survey Area Name: Warehouse 213 Warehouse 2/3 Footprint Final Status Survey 2-6 $
Temporary Restricted Areas 4 WJf420 FB-1500-01, Revision 0 Page 9 of 20 Grids are approximately 2m x 2m Soil Footprint Total Area - 2550 sq-m Grids are approximately 2mx 2m Soil Footprint Total Area -2550 sq-rn
Maine Yankee AfineYne eoms ihgPqetVro rnMap ID#: FB1500 DP REF Decommissioning Team IMaine YankeeDecommissionintg Project Survey Fori Revised: 11-3-04 Survey Type: O Characterization O Turnover
- Final Status Survey i Survey Area Name: Warehouse 213 Warehouse 2/3 Footprint Final Status Survey Direct Point Reference Map 55 .J---- _--- E I22-I2 .....
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Maine Yankee M YMaine Yankee DecommissioningProjectSurvel Form Revi eD#: 1FB-1500-la Decommissioning Team Survey Type: ] Characterization ] Turnover U Final Status Survey Survey Area Name: Warehouse 2/3 Warehouse 2/3 Footprint Final Status Survey 1-~
Survey Scans 001 - 030 I 3mrx3mrGrid,typ. r--- ] 1.5m x 6m Survey Grid, typ.
L -J FB-1500-01, Revision 0 Page 11 of 20 Soil Footprint Total Area - 2550 sq-m E _1 =1 _ ] 1mx 9m Survey Grid, typ. Total Survey Grid Area is approximately 270 sq-m
Maine Yankee Map ID#. FB 1500-LOC Decommissioning Team aine YankccDeconnissioning ProjectSurej'Form IRevised: 2-1-05 Survey Type: l Characterization ] Turnover U Final Status Survey Survey Area Name: Warehouse 2/3 Warehouse 2/3 Footprint Final Status Survey *1-Background Locations Map 1x l-b EXPECTED BACKGROUND RANGE
- 9300 cpm to 11300 cpm for GROUP A grids
-9600 cpm to 1600 cpm for GROUP B grids
- 8900 cpm to 10900 cpm for GROUP Cgrids
- 8500 cpm to 10500 cpm for GROUP D grids I 13mrx3mGrid,typ. - 7900 cpm to 9900 cpm for GROUP Egrids L -J FB-I500-01, Revision 0 1 _ __ ]
_1 1m x 9m Survey Grid, typ. Page 12 of 20 Soil Footprint Total Area - 2550 sq-m Total Survey Grid Area is approximately 270 sq-m
Attachment 2 Survey Unit Instrumentation FB-1500-01, Revision 0 Page 13 of 20
TABLE 2-1 INSTRUMENT INFORMATION E-600 S/N SPA3 Probe S/N 2490 726554 2488 725328 1622 j 2056 2489 2253 HPGc Detectors (Laboratory Analysis)
Detector No. MDC (pCi/g)
FSSI 0.035 to 0.06 FSS2 0.035 to 0.06 TABLE 2-2 INSTRUMENT SCAN MDC, INVESTIGATION LEVEL, AND DCGL Parameters Instrument: SPA-3 Comments Scang) 5.9 pCifg Cs-137 LTP Rev 3 Table 5-6 12,700 Group A Investigation Level 13,000 Group B (Alarm Setpoint) 12,200 Group C (cpm) 11,800 Group D 11,100 Group E DCGL Approved DCGL for land areas (PCilg) 4.2 pCi/g Cs-137 outside the Restricted Area, (pi/g)_ _LTP Section 6.7 (Reference 2)
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Attachment 3 Investigation Table (No Investigations Required)
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Attachment 4 Statistical Data FB-1500-01, Revision 0 Page 16 of 20
Survey Package FB 1500 Unit I Soil Sign Test Summary fiIn'iEva ua on'Input Va es * ;' i 7Comm.ents Survey Package: FB 1500 Warehouse 2/3 footprint Survey Unit: 01 Evaluator: DA DCGL,: 4.20E+00 Cs-137 DCGL DCGLemc: N/A Class 3 Area LBGR: 3.51 E+00 adjusted Sigma: 2.30E-01 LTP Rev 3, Table 5-1C (FR1000/FR1800)
Type I error: 0.05 Type II error: 0.05 Nuclide: CS-137 Soil Type: N/A eculate__v_' ____ ':iC mr i Zl,{ 1.645 ZI-Pr -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: 14 Median: 4.35E-02 Mean: 4.26E-02 Net Sample Standard Deviation: 5.51 E-03 Total Standard Deviation: 5.51 E-03 Maximum: 5.59E-02 Adjusted N Value: 14 S+ Value:. '14 Critical Value:. 10 Sign test results: Pass l Sommentsi.9 U..i Sufficient samples collected: Pass Maximum value <DCGLW,, Pass Median value <DCGL,,,' Pass Mean value <DCGLM: Pass Maximum value <DCGLemc: ,Pass N/A for Class 3 Total Standard Deviation <=Sigma: Pais Criteria comparison results: a The survey unit passes all conditions:l - Pass Survey Unit Passes FB 1500-SU1-SoilSign.xAs 2/3105 12:29 PM FB-1500-01, Revision 0 Page 17 of 20
FB-1500 SU-1 Quantile Plot 6.OOE-02 5.OOE-02 A
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One-Sample T-Test Report Page/DaterTime 2 213105 1:16:18 PM Database C:\Program Files\NCSS97\FB1500 SU-1.SO Variable C2 Plots Section Histogram of FB-1 500, SU-1 Ch E
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Activity (pCi/g)
FB-1500-01, Revision 0 Page 19 of 20
One-Sample T-Test Power Analysis Page/Date/Time 2 2/3/05 1:17:19 PM Chart Section Retrospective Power Curve 1.0- I I
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0.0 0 - A 6 Survey Unit Mean (pCi/g)
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