ML050590052
| ML050590052 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/17/2005 |
| From: | Dockins L, Olsen C, Packer J, Pillsbury G, Randall D Maine Yankee Atomic Power Co |
| To: | Document Control Desk, NRC/FSME |
| References | |
| FD-3500-03, Rev 0 | |
| Download: ML050590052 (20) | |
Text
I I MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-3500 STORM DRAINS SURVEY UNIT 3 Prepared By: i9 if2 Date: 2 - XOS FSS Engineer - Signature Pl7/c A cwq-a l Printed Name Reviewed By: ___ Date: a- co'o5 FS JSpecialist - Signature Printed Name Reviewed By: Date: l FEB.S Independent Review - Signature
'Printed Name Approved By: __ Date: Si7
/* FSS, MOP - Signature
£ c,, R -k Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-3500 STORM DRAINS SURVEY UNIT 3 A. SURVEY UNIT DESCRIPTION FD-3500 Survey Unit 3 is the footprint associated with buried storm drain piping, which was excavated and removed, prior to survey. The two portions of the excavated piping, which were not surveyed as part of FR-01 I I Yard West Excavations Survey area, make up this survey unit. Due to its proximity with and physical similarity to FR-0111, the design parameters (including the contaminated soils DCGL, Sigma and use of the ISOCS instrument for scanning) mirror those for that survey area.
The survey unit excavations were located at approximate coordinates 407,625 N / 623,575 E and 407,950 N / 623,750 E using Maine State Coordinate System (West Zone) NAD 1927.
These locations are referred to as Outfall 6 and Gate 4 excavations respectively (portions of Storm Drain Sections 6 and 7 as described in Attachment 5A of the LTP). The location of the survey unit in relation to the site is shown on map FD3500U3-SITE. All maps referenced in this release record are provided in Attachment I unless otherwise noted. The survey unit is approximately 295 m2 .
B. SURVEY UNIT DESIGN INFORMATION Survey Unit 3 met the LTP Revision 3 definition for a Class I survey unit due to the Class I storm drain being removed from the excavation. The survey unit design parameters are shown in Table 1. Given a relative shift of 0.8, it was determined that 40 direct measurements were required for the Sign Test. 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 43 locations which are illustrated on map FD3500-U3DIRT (Attachment 1).
Except for five locations which were inaccessible due to safety concerns, direct measurements (soil samples) were collected from required locations and analyzed with laboratory gamma spectroscopy instrumentation.
Five direct measurement location were inaccessible due to safety concerns involving the slope of the excavations. At these locations (S003, S004, S007, S008, and S009) ISOCS direct measurements were used in place of soil samples. The ISOCS direct measurements were counted at a height of 0.7 m (- 1.5 m2 field of view) to MDAs that are comparable to
.soil sample direct measurements.
In accordance with the LTP, scans covering 100% of the 295-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 survey scans are shown on map FD3500U3-SCAN.
FD-3500-03, Revision 0 Page 2 of 20
The ISOCS scans were configured to ensure 100% scan coverage of all exposed surfaces within Survey Unit 3. 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 DCGLErC. 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. Further, since the investigation level was always less than the design DCGLEMC, no EMC sample size adjustment was necessary.
TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 295 m2 Class 1, < 2,000 m2 Based on an LBGR of 1.2 pCi/g, Number of Direct 40 sigmal of 1.33 pCi/g, and a relative Measurements Required shift of 0.8.
Type I = Type 11 = 0.05 Sample Area 7.4 m2 295 M2 / 40 = 7.4 m2 Sample Grid Spacing 2.7 m (7.4)____
Scan Grid Area ISOCS scan at 3-meters See Section B Area Factor 2.8 Class I Area, LTP Table 6-12 Scan Area 295 m' Class I Area - 100%
ScnInetiaio evl 1.0 pCifg Cs-137 ISOCS investigation levels with Scan Investigation Level 0.36 pCi/g Co-60 detectoreit 3-meter height 0.36 (Reference 6)
DCGL 2.39 pCi/g Cs-037 References 4 and 7
____ _____ ____ 0.86 pC i/g Co-60_ _ _ _ _ _ _ _ _ _ _ _ _ _
. 6.69 pCi/g Cs-137 DCGL x Area Factor for Class 1 Design DCGLEMC 2.41 pCilg Co-60 survey unit, per LTP Section 5.6.3 C. SURVEY RESULTS A total of 43 direct measurements were performed in Survey Unit 3. Three samples contained only Cs-137 with levels of residual activity below the DCGL. All other measurements were below the MDA for plant-derived nuclides. The results are presented in Table 2.
ISOCS gamma scans were performed at 55 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 25% of the DCGL. All MDAs were below the investigation levels. The scan measurements did not identify any plant-derived activity above the MDA. Therefore, no investigation surveys were performed as a result of the scan surveys.
LTP Revision 3, Table 5-1C for RCA Yard West, ROI00 FD-3500-03, Revision 0 Page 3 of 20
TABLE 2 DIRECT MEASUREMENTS Sample Number Cs-137 (pCi/g) Uncertainty (pCilg)
FD3500301SO01 < 4.64E-02 FD3500301S002 < 4.70E-02 FD3500301S003 < 2.65E-0I FD3500301S004 < 2.42E-0I FD3500301S005 < 4.39E-02 FD3500301S006 3.98E-01 5.40E-02 FD3500301S007 < 2.44E-0I FD3500301S008 < 2.75E-OI1 FD3500301S009 < 2.59E-OI1 FD3500301SO10 < 4.61E-02 FD3500301SOII < 4.38E-02 FD3500301S012 < 4.27E-02 FD3500301S013 < 4.92E-02 FD3500301S014 < 4.32E-02 FD3500301S015 < 5.00E-02 FD3500301S016 < 4.43E-02 FD3500301S017 < 4.13E-02 FD3500301S018 < 4.08E-02 FD3500301SO19 < 4.07E-02 FD3500301S020 < 4.58E-02 FD3500301S021 < 4.45E-02 FD3500301S022 < 4.25E-02 FD3500301S023 < 4.53E-02 FD3500301S024 < 4.79E-02 FD3500301S025 < 5.57E-02 FD3500301S026 < 4.91E-02 FD3500301S027 < 5.06E-02 FD3500301S028 < 4.54E-02 FD3500301S029 < 4.45E-02 FD3500301S030 < 5.06E-02 FD3500301S031 1.32E-01 3.1lE-02 FD3500301S032 < 4.51E-02 FD3500301S033 < 4.09E-02 FD3500301S034 < 4.1OE-02 FD3500301S035 < 4.67E-02 FD3500301S036 < 5.21E-02 FD3500301S037 < 6.53E-02 FD3500301S038 < 5.97E-02 FD3500301S039 < 4.65E-02 FD3500301S040 < 6.87E-02 FD3500301S041 7.87E-02 3.18E-02 FD3500301S042 < 5.57E-02 FD3500301S043 < 5.85E-02 Mean 8.31E-02 Median 4.70E-02 Standard Deviation 8.43E-02 Range 4.07E 3.98E-O1
"<" indicates MDA value. Bold indicates positive detection value. All Co-60 results were < MDA.
FD-3500-03, Revision 0 Page 4 of 20
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 are provided in Table 2. Both the mean and median activities were less than the DCGL for Cs-l 37 (all Co-60 values were less than MDA).
Positively detected values are bolded in the table. Of the 43 soil samples collected, 3 identified Cs-137 activity below the DCGL value of 2.39 pCi/g. No other plant-derived radionuclides were detected. The maximum direct measurement result was less than 17% of the DCGL. Since the activity is less than the action levels in LTP Table 5-7, no investigations are required.
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 per Reference 5)for disturbed soil from the survey unit sample mean activity (0.083 pCi/g). The result is a net activity of (-0.1 I pCi/g). This would equate to an annual dose rate of 0 mrem/y. 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 the 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 below the DCGL of 2.39 pCi/g for Cs-137.
FD-3500-03, Revision 0 Page 5 of 20
- 3. A Histogram Plot was also developed based on the data values. This plot shows a log-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 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.
H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 3 was designed, performed, and evaluated in the December 2004 time frame. The design was performed to the criteria of the LTP Revision 3 (References 2 and 4). LTP Change No.05-001 (Reference 7) modified the Table 6-11, "Contaminated Material DCGL," to reflect an increased Deep Soil DCGL of 0.86 pCi/g for Co-60. The change in the annual dose from Deep Soil had no impact on the data evaluation for this survey unit since all results were less than MDA for Co-60. No subsequent LTP changes with potential impact to this survey unit need to be evaluated.
- 1. CONCLUSION The FSS of this survey unit was designed based on a Class 1 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 2.39 pCilg 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 log-normal distribution.
FD-3500-03, Revision 0 Page 6 of 20
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. 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 FD-3500 Survey Unit 3 meets the release criteria of 10CFR20.1402 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 Procedure 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-003-04, Use of Canberra In Situ Object Counting System (ISOCS) for FSS Surveys
Attachment 1 Survey Unit Maps FD-3500-03, Revision 0 Page 8 of 20
DecoMainssionngkTeam Maine Yankee Decommissioning Project Survey Map I Map ID# FD3500U3-SITE SurveyType: [] Characterization [] Turover
- nal Status Survey Survey Area Name: Site Locator IreporedB Larry N. Dockins Dote: 12/18/04 623,500E 623,600E 623,700E 623,800E 623,900E 624,OOOE - z z7 z z Iz z O 0 0 0 0) 0 Co CD 0 ci Ci Ci LO 0PODO 0 K.. K- P. K- K.
0 o Ci ci ci C 06 FD-3500-03, Revision 0 Page 9 of 20
MaineYainkee l Maine Yankee DecommissioningProject Survey Map lMap ID# FD3500U3-SCAN Suvey Type: [] Characterization D Turnover
- FlnalStatusSuvey SurveyArea Nare: Scan Locations Prepared By,. Larry N. Dockins Date: 12/1 7/04 f
Maine Yankoo Maine Yankee Decommissioning Project Survey Map Map ID# FD3500U3-DIRT Decomnmisnsnon TeamI SurveyType: ] Characterization E] Turnover
- Flnal Status Survey Survey AreoName: Direct Locations Prepared By- Larry N. Dockins Date: 12/1 7/04 MN N
FD-3500-03, Revision 0 Om lOm Page 11 of 20 ref.
Maine Yankee ISre a Decomrnmssloninca Team I Maine Yankee DecommissioningProjectSurveyMa Map ID# FD3500U3-INFO SurveyType: D Charocterzalion [ Turriover
- Final Status Survey SurveyArea Name: Excavation Depths lPrepaied y: Larry N. Dockins Date: 12/27/04 I N =20'el FD-3500-03, Revision 0 Om lOm Page 12 of 20
Attachment 2 Survey Unit Instrumentation FD-3500-03, Revision 0 Page 13 of 20
TABLE 2-1 INSTRUMENT INFORMATION ISOCS Detectors (Field Measurements)
Detector No. MDC (pCi/g) 7780 0.14 to 0.28 7722 0.13 to 0.27 7607 0.16 to 0.32 HPGe Detectors (Laboratory Analysis)
Detector No. MDC (pCi/g)
FSS1 0.04 to 0.07
_SS2 0.04 to 0.06 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL AND DCGLEMC Parameters Instrument: ISOCS Comments Scan MDC 0.13 to 0.32 pCi/g - 25% DCGL Conservatively used DCGL DCGL 2.39 pCilg Cs-137 for land areas inside the 0.86 pCi/g Co-60 Restricted Area (References 4 and 7)
Investigation Level 1.0 pCi/g Cs-137 (Reference 6)
(ISOCS a-,3 m) 0.36 pCi/g Co-60 (e ren 6) 6.69p~ig C- 13 7 DCGL x Area Factor for Design DCGLEMC 6.69 pCi/g Cso137 Class I survey unit, per LTP 2.41 ~i/g o-60Section 5.6.3 FD-3500-03, Revision 0 Page 14 of 20
Attachment 3 Investigation Table (No Investigations Required)
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Attachment 4 Statistical Data FD-3500-03, Revision 0 Page 16 of 20
Survey Package FD-3500 Unit 3 CS-137 Soil Sign Test Summary
> ; E va ationliputValues ,- . 'omments:
Survey Package: FD-3500 Strorm Drain Piping footprint Survey Unit: 03 Evaluator: DR DCGL,: 2.39E+00 DCGLrnp: 6.69E+00 LBGR: 1.20E+00 Sigma: 1.33E+00 RCA Yard West Type I error: 0.05 Type II error: 0.05 Nuclide: CS-1 37 Soil Type: N/A
- ;,t--C61dulatodvalue".;r* 7 or Ota' "" t r irSflo 6mme Zt < ,: 1.645 Zap0: 1.645 Sign p: 0.788145 Calculated Relative Shift: 0.8 Relative Shift Used: 0.8 Uses 3.0 if Relative Shift is >3 N-Value: 33 N-Value+20%: 40 Number of Samples: 43 Median: 4.70E-02 Mean: 8.31E-02 Net Sample Standard Deviation: 8.43E-02 Total Standard Deviation: 8.43E-02 SRSS Maximum: 3.98E-01 itt -<aZ'&1 ¢sigW st ResultsV -* - Comments Adjusted N Value: - 43 S+ Value: 43 Critical Value: 27 Sign test results: ,.- Pass Sufficient samples collected: -. Pass _
Maximum value <DCGL,: - Pass Median value <DCGLW ,: Pass Mean value <DCGLW . Pass Maximum value <DCGLm: Pass Total Standard Deviation <=Sigma:. .. Pass Criteria comparison results: Pass___
The survey unit passes all conditions: Pass SU Passes FD-3500-Su3-SoilSign-CS-137 2114/05 9:01 AM FD-3500-03, Revision 0 Page 17 of 20
FD 3500 SU-3 Quantile Plot 4.50E-01 4.00E-01 1:
3.50E-01
'TI 3.00E-01 0.
~ 0 2.50E-01
- Activity (pCi/g) 0 4-.
0 x %-%.
2.OOE-01 -Median (pCi/g)
O0A: 4-a FSI
%W 1.50E I.
1.OOE-01 5.00E-02 wwr i -0 0 O.OOE+00 -1 0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 2/14/05 8:56:01 AM Database C:kProgram Files\NCSS97\FD3500 SU-3.SO Variable C2 Plots Section Histogram of FD-3500, SU-3 50o (n
a' 38 E
Ci) o 25
.0 E
Z 13 0.000 0.100 0o200 . . 0.300 *
- 0400 Activity (pCilg)
FD-3500-03, Revision 0 Page 19of20
One-Sample T-Test Power Analysis Page/Date/Time 2 2/17105 8:51:24 AM Chart Section Retrospective Power Curve 1.0.-. 0
- I
- I 0.8 -- - - - -
, , I I I a) 0.6- - - - ' - I I I , I I 0 , ,
0_ , II 0.2- . ,
-1 0.0 . I I 0.0 0.5 1.0 1.55I 2'0 2'5 Survey Unit Mean (pCi/g)
FD-3500-03, Revision 0 Page 20 of 20