ML050590106
| ML050590106 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/17/2005 |
| From: | Cooper W, Dockins L, Packer J, Pillsbury G, Randall D Maine Yankee Atomic Power Co |
| To: | Document Control Desk, NRC/FSME |
| References | |
| FR-0900-02, Rev 0 | |
| Download: ML050590106 (21) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0900 BALANCE OF PLANT AREAS SURVEY UNIT 2 Prepared By: /9.7 Ago FSS Engineer - Signature YX Date: /? -/4 -Py f) 3/e 4 A{>ftt Printed Name Reviewed By: Date: I FSS S cialist - Signature LC-.,t A./f 3c- D e-;s Printed Name Reviewed By: E Date: l Z//6' Independent Review -
Signature Approved By: _ Date: a/, ?/
6Suprinen~nt, FSS -
Signature I7 Approved By: ,, 4- Date: z/,z F89,MOP - Signature Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0900 BALANCE OF PLANT AREAS SURVEY UNIT 2 A. SURVEY UNIT DESCRIPTION FR-0900 Survey Unit 2, Balance of Plant Areas, consists of the land area inclusive and adjacent to scan grid S103 of FR-0900 Survey Unit 1,which Nvas a Class 3 survey unit. Scan grid S 103 was a I m by l Om area and was initially a bias scan location. The scan of grid S 103 resulted in a verified alarm. The follow-up investigation determined that the cause of the scan alarm was a small volume of contaminated soil media. This contaminated media was completely collected into a 1-liter sample. The contaminated portion was subsequently segregated to a 100 g aliquot of soil media that was found to contain Co-60 with a specific activity of 1,030 pCi/g. In accordance with the License Termination Plan (LTP), (Reference
- 3) the subject area was reclassified into a Class I survey unit.
The bias selection of grid S103 in Survey Unit I was based primarily on the topology and drainage of the surrounding area and the fact that it lay in close proximity to an exterior staircase walkway and a paved roadway. Since the adjacent roadway was crowned and will be surveyed as a separate survey area (FR-2900; Roads/Railroad), 100% of the down gradient ditch, and a portion of the lower hillside adjacent to the ditch, wvas selected for reclassification.
Since the contaminated area was isolated to a small portion of a 10 m2 scan grid of FR-0900 Survey Unit 1, the 104 m2 area of FR-0900 Survey Unit 2 was deemed adequate to achieve the design objectives of both the Class I survey unit and a Class 2 buffer unit, which would typically surround a Class 1 survey unit. Survey Unit 2 grids S036 through S045 approximate the location of Survey Unit I grid S 103.
FR-0900 Survey Unit 2 is located at the approximate coordinates of 407,900 N and 623,920 E using the Maine State Coordinate System (West Zone), NAD 1927. The survey unit area is shown in relation to other major site structures in map FRO900-02-Site. All maps referenced in this release record are provided in Attachment 1, unless otherwise noted. The survey unit's total area is approximately 104 m2 .
FR-0900-02, Revision 0 Page 2 of 21
B. SURVEY UNIT DESIGN INFORMATION FR-0900 Survey Unit 2 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 and are illustrated on the map FRO900-02-Directs (Attachment 1). All direct measurements consisted of soil samples obtained at the required locations. The samples are analyzed with laboratory gamma spectroscopy.
Scan grids of nominal I m x I m size were established as indicated on survey maps. A 100%
scan coverage of the area was required. Scan areas are indicated on map FRO900-02-Scan (Attachment 1). One meter by one-meter scan grids were made to provide a total of 104 m2 (100% of the survey unit area coverage).
The instruments used in this survey 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. Further, since the investigation level at the alarm setpoint was always less than the design DCGLENIC, no EMC sample size adjustment was necessary.
- Background values were established for the scan nmeasurements 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 background within the survey unit, the grids were divided into two different background groups based on the location. These are specified in Table I and shown on map FRO900-02-Scan.
FR-0900-02, Revision 0 Page 3 of 21
TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit Dcsign Criteria Basis Area 104 m2 See discussion Section A Based on an adjusted LBGR of Number of Direct 14 2.76 pCi/g, sigma' of 0.48 Measurements Required pCi/g, and a relative shift of 3.0.
Type I= Type 11 = 0.05 Sample Area 7.43 m2 104 m2 / 14 samples Sample Grid Spacing 2.72 m (7.43 m2 ) Y2 Scan Grid Area lmx Im Area Factor 2.8 LTP Table 6-12 Scan Survey Area 104m 2 Class I area-100%
Background , .2,;..
SPA-3 (scan) 11,800 cpm Group I.
12,900 cpm Group 2 S n 3 sigma of background EC-009-01 (MY) (Reference 1)
.:. , r. '. .. ..
plus BKG. , ,. . See Table 2-2 (Attachment 2)
DCGL 4.2 pCi/g . . LTP Revision 3 (Reference 2)
Design DCGLEMC 11.76 pCilg Area Factor x DCGL C. SURVEY RESULTS Fourteen direct measurements were required, 20 direct soil measurement locations fit within the survey unit. Twenty samples were collected and the results are presented in Table 2. All direct measurements were below the DCGL. Fourteen verified alarms were received during the soil scans. The investigation of verified alarms is discussed below.
Design sigma based on LTP Revision 3, Table 5-IC, Balance of Plant Areas, FR-0900.
FR-0900-02, Revision 0 Page 4 of 21
TABLE 2 DIRECT MEASUREMENTS Sample Number Cs-137 pCilg*
FR-0900-02-SOOI < 5.91E-02 FR-0900-02-S002 < 4.40E-02 FR-0900-02-S003 < 6.9313-02 FR-0900-02-S004 < 5.5313-02 FR-0900-02-S005 < 6.12E-02 FR-0900-02-S006 < 5.81 E-02 FR-0900-02-S007 < 6.0313-02 FR-0900-02-S008 < 5.43E-02 FR-0900-02-S009 . < 5.04E-02 FR-0900-02-S010 . <.6.31 E-02 FR-0900-02-S011 < 5.26E-02 FR-0900-02-S012 <5.4813-02 FR-0900-02-S0 13 < 4.7713-02 FR-0900-02-S014 < 4.78E-02 FR-0900-02-S01 5 < 4.7313-02 FR-0900-02-S0 16 < 4.68E-02 FR-0900-02-S017 < 5.12E-02 FR-0900-02-SO18 < 5.24E-02 FR-0900-02-S019 < 5.45E-02 FR-0900-02-S020 < 4.7713-02 Mean 5.39E-02 Median 5.35E-02 Standard Deviation 6.46E-03 Range 4.40E 6.93E-02
"<" indicates value less than MDA, MDA value is reported
- Samples were also analyzed for Co-60; all were less than an MDA of 0.10 pCilg FR-0900-02, Revision 0 Page 5 of 21
D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS The 14 scan grids that had verified alarms were investigated by taking a soil sample at the highest SPA-3 count rate location for each grid. The soil sample results are presented in Table 3-1. All samples collected were less than the MDA. Consequently, they add no contribution to the DCGLEMC unity fraction.
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-137. All results were less than the MDA. The maximum direct measurement MDA was approximately 1.65% of the Cs-137 DCGL. The level of activity is consistent with disturbed soil.
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 for disturbed soil from the survey unit sample mean activity. When the background value of 0.19 pCi/g (Reference-4)is subtracted
. . I from the sample results for the survey unit, the result is a negative. This would be equivalent to an annual dose rate of 0 mremly. .However, for purposes of demonstrating compliance with the radiological criteria for license'termination and the enhanced State criteria, .. . . .. 1.
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 sample population whose results were all less than MDA. All of the measurements are well below the DCGL of 4.2 pCi/g.
FR-0900-02, Revision 0 Page 6 of21
- 3. A Histogram Plot was also developed based on the direct measurement values. This plot shows that the direct data were essentially a normal distribution with no outliers.
- 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 TIlE EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class I area; the FSS results met the requirements for that classification. The direct measurement sample standard deviation was less than the design sigma. Thus, no additional measurements were required.
- 11. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 2 was designed, performed and evaluated in mid 2004. The design was performed to the criteria of the LTP, Revision 3 and Addenda (Reference 3). No subsequent L,~change~s with potential impact-to this survey unit needed to be evaluated. .
I. CONCLUSION .. ..
The FSS of this survey unit was designed based on the LTP based reclassification 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 normal distribution, with no outliers.
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. All verified alarms were investigated and determined not to add to the DCGLENMc unity fraction.
It is concluded that FRO900 Survey Unit 2 meets the release criteria of I OCR20.1402 and the State of Maine enhanced criteria.
FR-0900-02, Revision 0 Page 7 of 21
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-02-061, dated November 26, 2002
- 4. Approach for Dealing with Background Radioactivity for Final Status Surveys, Attachment E to Maine Yankee Procedure PMP 6.7.8, FSS Data Processing and Reporting FR-0900-02, Revision 0 Page 8 of 21
Attachment I Survey Unit Maps FR-0900-02, Revision 0 Page 9 of 21
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Maine Yankee Decommissrlonlnc Team II Maine YankeeDecommissioningProject Survey Map IMaPD#FRO900-02-Scon ID#FO0-2Sa Survey Type: E Charocterization [] Turnover 3 Final Status Survey SuiveyArea Name: Scan Grids Prepcredw. Larry N. Dockins Date: 7/20/04
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j S001 5002 5003 5004 5005 S006 5007 S008 5009 S010 S0115 S0121 013 S1U S01155016 5017 S0 1 5019 5020 5021 S022 S023 5024 5025 1026 5027 S028 5029 50301303115032 5033 S034 5035 5036 5037 5038 S039 S040 5041 5042 504315044 5045 5046 S047 5048 5049 5050 5051 5052 SOS350 055 5056 l05715058 5059 5060 5061 5062 50631 5064 5065 1066 5067 5068 5069 5070 5071 5072 S073 5074 5075 S076 s07n S078 S079jS080 07 SooSB I5081
.. __1__82.11....1.... 508615087 5082150831508415085 0
5088 10891 5090 S091 S0911 50931 50941 5095 5096 5097 S598 5099
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5100
-410 5101 j 5102
-2 51031 10 20m Scan Grids (I m x 1m)
Group I Grids: S027, S053, S087, and S099 through S103 Group 2 Grids: S001 through S026, S028 through S052 S054 through S086, S088 through S098 and S104 FR-0900-02, Revision 0 P13oe 11 nf ) 1
Mahne Yankee Mi D R900-iet Decommeissloning Teom I Maine Yankee Decommissioning Project Survey Map IMaPID#FRO900-02-Directs Survey Type: [] Characterization [] turnover
- Finl Status Survey SurveyArea Name: Direct Locations Prepared By: Larry N. Dockins Date: 7/20/04 1 J
I X X X X X x X X9 X X9 5001 S002 5003 5004 5003 S006 5007 5008 5009 1010 So01 5012 3013 5014 5015 5016 5017 sole 5019 5020 5.6 0.4 X li IK Bx 1K x ~ X >1 . Ex xg V.
I 10 20M Direct Points FR-0900-02, Revision 0 Page 12 of 21
Attachment 2 Survey Unit Instrumentation FR-0900-02, Revision 0 Page 13 of 21
TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN Probe SIN (type) 2618 725328 (SPA-3) 1648 2055 (SPA3) 2490 2254(SPA-3) 2490 725328 (SPA-3) 2621 2055 (SPA3) 1622 725328 (SPA-3) 2617 2055 (SPA3)
IIPGe Detectors for Lab Analysis of Volumetric Samples Detector Number MDC (pCi/g)
FSS-l 0.04 - 0.10 FSS-2 0.04 - 0.10 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL, AND DCGLEMc Detector SPA-3 Comments DCGL Approved DCGL for land areas (pCilg) 4.2 outside the Restricted Area,
__ _ _ _ _ _ LTP Section 6.7 (Reference 2)
Scan MDC 5.9 Design Scan MDC, (pCi/g) LTP Table 5-6 (Reference 2)
Investigation Level 14,300 Group I (Alarm Setpoint) 15,500 Group 2 (cpm)__ _ _ _
Design DCGLEMC (pCi/g) 11.76 (from Release Record Table 1)
FR-0900-02, Revision 0 Page 14 of 21
Attachment 3 Investigation Table FR-0900-02, Revision 0 Page 15 of 21
TABLE 3-1 INVESTIGATION TABLE FSS SURVEY RESULTS INVESTIGATION RESULTS Alarm Scan Scaler Grid Reason Setpoint Measurement Measurement. Samplc ID Cs-137 DCGL (cp (cpm) (cpm) : (pCig) Comparison S015 ALARM 14,300 14,770 13,920. XR0900021SO15SS <5.66E-02 <DCGL S027 ALARM 15,500 16,540 15,430 . XR0900021 S027SS <4.87E-02 <DCGL S028 ALARM 14,300 14,630 13,960. - XR0900021 S028SS <4.80E-02 <DCGL S053 ALARM 15,500 16,200 15,190 . XR0900021S053SS <6.1 OE-02 <DCGL S055 ALARM 14,300 14,350 13,430 XR0900021S055SS <6.18E-02 <DCGL S073 ALARM 14,300 14,470 15,310 . XR0900021S073SS <5.22E-02 <DCGL S076 ALARM 14,300 14,400 13,420 XR0900021 S076SS <5.23E-02 <DCGL S078 ALARM 14,300 15,260 12,980 XR0900021 S078SS <5.80E-02 <DCGL S090 ALARM 14,300 14,490 13,430 XR0900021 S09OSS <4.91 E-02 <DCGL S095 ALARM 14,300 14,360 12,700 XR0900021SO95SS <5.61 E-02 <DCGL S096 ALARM 14,300 14,920 12,430 XR0900021 S096SS <5.33E-02 <DCGL S097 ALARM 14,300 15,420 12,520 XR0900021 S097SS <6.05E-02 <DCGL S098 ALARM 14,300 14,890 12,970 XR0900021 S098SS <5.84E-02 <DCGL S104 ALARM 14,300 16,000 14,580 XR090002IS104SS <5.93E-02 <DCGL
. SU Mean / DCGL 0.013 Total 0.013 NOTES: 1. "<" indicates value less than MDA, MDA value is reported.
FR-0900-02, Revision 0 Page 16 of 21
Attachment 4 Statistical Data FR-0900-02, Revision 0 Page 17 of 21
Survey Package FRO900 Unit 2 CS-137 Soil Sign Test Summary
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Survey Package: FRO900 Balance of Plant Areas Survey Unit: 02 Evaluator: DR DCGLY 4.20E+00 DCGL,,,: 1.18E+01 LBGR: 2.76E+00 Sigma: 4.80E-01 Type I error: . 0.05 Type II error: 0.05 Nuclide: CS-1 37 Soil Type: N/A
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.'1.645 Z.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
.'@^.Samrtpl-e Data Valu'esŽ ,-,.Z..!. ,,irbm uesblz-.'e-' I Number of Samples: 20 Median: . -5.35E-02 Mean: a c-.5.39E-02 Net Sample Standard Deviation: 6.46E-03 Total Standard Deviation: 6.46E-03 SRSS Maximum: : 6.93E-02 Adjusted N Value: - ' - 20 S+Value:j. 20 Critical Value: : 14 Sign test results: :'. .Pass Sufficient samples collected: Pass Maximum value <DCGL,,: Pass Median value <DCGL,: 'Pass Mean value <DCGL, Pass Maximum value <DCGL,,c: Pass Total Standard Deviation <=Sigma:.Pass__
Criteria comparison results: _ ._.'__Pass___
srvy unit psssal c s. - Pa The survey unit passes all conditions:l '~,;i ',Pasrs SU Passes FRO900-S1.12-SoliSign-CS-1137 12/14/04 7:20 AM FR-0900-02, Revision 0 Page 18 of 21
FR-0900 SU-2 Quantile Plot 0.08 0.07 0.06 .. .
- 0) 0.05 0 0
- T (D 0 9-
- Activity (pCi/g) 0.04 O 0 C.
-1.._
- Median (pCi/g) vt5 0 5 5 0.03 0.02 0.01 0
0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 12/14/04 12:17:40 PM Database C:\Program Files\NCSS97\FRO900 SU-2.SO Variable C2 Plots Section Histogram of FR-0900, SU-2 C,,
10) a)
z Activity (pCVg)
FR-0900-02, Revision 0 Page 20 of 21
One-Sample T-Test Power Analysis Page/Date/Time 2 12/13/04 12:09:06 PM Chart Section Retrospective Power Curve 1.0-0.8 -_- -
ea, a) ° .6 , I 0 .2 , . I.
Survey Unit Mean (pCi/g)
FR-0900-02, Revision 0 Page 21 of 21