ML043290314
| ML043290314 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 11/17/2004 |
| From: | Pillsbury G Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FB-1100-01, Rev 0 | |
| Download: ML043290314 (27) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB- 1100 CIRCULATING WATER PUMP HOUSE SURVEY UNIT I Date Prepared By: _ _ _
S Enginee/ nat re cam M/M Printed Name Date-Reviewed By: o Dlilo FSS Spec' l gnature MOWS toting Printed Name Date:
Reviewed By: a94 Z_ ? , /O-2 7- O Independent Reviewer -
Signature Approved By: Date//Z /-
Su intendeV3 aur nrinted Name Date:
Approved By:
HESS, AlOP - Signature Prie Am ae Printed Name
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-1100 CIRCULATING WATER PUMP HOUSE SURVEY UNIT I A. SURVEY UNIT DESCRIPTION Survey area FB-1 100 pertains to the interior surfaces of the Circulating Water Pump House (CWPH). This structure wvas a concrete and steel frame building constructed along the east shore of Bailey Point at Maine State Grid Coordinates 407500 N and 624400 E (See Map FB-I 100-SITE, Attachment ]). The structure extended from El. -22 feet to approximately El.
40 feet. The lower portion of the building was submerged below the low tide level. Only the portions of the building below El. 17 feet are included in this survey area. The rest of the structure was demolished.
The building contained four similar concrete bays which each contained a circulating water and a service water pump, as well as a traveling screen. The lower intake bays were nearly continuously immersed in river water during the life of the structure.
The survey unit has a total estimated area of 2200 m2 .
B. SURVEY UNIT DESIGN INFORMATION The structure was classified as a Class 3 survey unit per LTP Table 5-l B.
Since CWPH FSS and demolition activities (including backfill) would be accomplished prior to LTP approval, special survey design provisions for this survey unit were developed and incorporated into the LTP.' Survey unit design parameters for the concrete surfaces are summarized in Table 1.
It was determined that 14 direct concrete measurements were required for the Sign Test.
Measurement locations were determined randomly and are illustrated in survey maps FB 1100-01 through FB 1100-06 (Attachment 1). One sample location (C-00 I) was relocated because it could not be reached by man-lift. See map FB 100-02A (Attachment 1). Per LTP Section 6.6.10, the contaminated basement surface DCGL would be applied to structure surfaces in this survey unit. Once the direct readings were taken, removable contamination samples were obtained at each location.
Each concrete scan area was typically 2 in2 . Scans were made at each direct measurement location producing a total scan area of approximately 28 m2 , thereby exceeding the LTP Table 5-3 scan coverage requirement for this Class 3 survey unit (i.e., 1 % of 2200 M2 or 22 m2).
LTP Section 6.6.10, Revision 2 (Reference 1). All references to the LTP for this release record pertain to LTP Revision 1, unless othenvise noted. Section H reviews and evaluates subsequent changes to the LTP with potential impact to this FSS.
FB-1 100-01, Revision 0 Page 2 of 27
Both direct and scan surveys were performed using a gas-filled detector with a reduced efficiency (0.049) to adequately measure damp concrete. As an additional survey measure, smear samples were taken at each direct measurement location. This sampling was considered a confirmatory measure and not required for the FSS release decision.
Per special provisions for this survey unit (LTP Section 6.6.10), sediment samples for the pump bays were obtained and analyzed (for comparison against the surface soil DCGL). The sediment sampling locations were randomly selected and are illustrated in map FB 1100-08 (Attachment 1). In addition, wvater samples were obtained in each pump bay.
The survey instruments used, their MDC values, and alarm setpoints, are provided in Attachment 2. Background values were established for each particular direct measurement location. These background values were used to establish net activity for direct measurements, scan alarm set-points, and to confirm the scan MDCs used were appropriate.
TABLE I SURVEY UNIT DESIGN PARAMETERS Survcy Unit Design Criteria J Basis Area 2200 m2 No limit for Class 3 Area Based on an adjusted LBGR of Number of Direct 17,000 dpm/l 00 cm2 , sigma3 of Measurements Required 14 319 dpm/I 00 cm2 , and relative shift of 3.
Type I = Type 11 = 0.05 Sample Area N/A Class 3 Area Sample Grid Spacing N/A Class 3 Area Scan Grid Area 2 M2 Class 3 Area Area Factor N/A Class 3 Area ScnSr a28 Class 3 Area- 1% to 10%
Scan Survey Area 28 m (LTP Table 5-3)
Background ;. i 43-68 Direct and Scan A background measurement s N/A was made at each direct measurement point.
Scan Investigation Level - 0.5 DCGL EC 009-01 (Reference 2)
DCGL 4 180 00 2m' LTP 6.6.10 and Table 6-11, (CWPH Structure Surfaces)4 800p c LTP Revision I Design DCGLaIc N/A Class 3 Area 2
The development of the water film correction factor for concrete surfaces is documented in Maine Yankee calculation EC-033-01 (Reference 3).
3 Based on LTP Table 5-1 B.
4 Sediment samples, per LUP Section 6.6.10, were compared to the surface soil DCGL of 4.2 pCi/g (LTP Table 6-11).
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C. SURVEY RESULTS Fourteen direct concrete measurements were made in Survey Unit I with the results presented in Table 2. All direct measurements were below the DCGL.
The scan survey resulted in one verified alann. The investigation is discussed below.
TABLE 2 DIRECT MEASUREMENTS 5 Net ActivitY6 Gross Activitys cm2 ) l (dpm/100 cm 2 )
Sample Number (dpm/100 FB-1100-1 -COO1 5653 1118 FB-1100-1-C002 5215 1361 FB-1100-1-C003 5426 1458 FB-1100-1-C004 4389 1118 FB-1100-1-C005 5669 1490 FB-1100-1-C006 5345 1393 FB-1100-1-C007 5021 1458 FB-1100-1-C008 4503 1312 FB-1100-1-C009 4438 1182 FB-1100-1-COI0 4762 1263 FB-1100-1-COI 4600 1701 FB-1100-1-C012 5361 1684 FB-1100-1-C013 5572 2025 FB-1100-1-C014 4600 1020 Mean 5040 1399 Median 5118 1377 Standard Deviation 478 271 Range 4389 - 5669 1020 -2025 D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS The surface scans identified one location (Grid C-013) for investigation. Investigation package XB-1 100 required additional surface measurements, in situ measurements using the GR-130 and volumetric samples. The results of the investigation are provided in Attachment 3.
5 For this FSS, 10-minute count times were used for both direct and background measurements.
6 Individual ambient background counts were performed for each sample location and these were used to determine net activity. (The average background value was 225 c/m.) This accounts for the different standard deviations.
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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. Without subtracting background, all direct measurement results were below the DCGL. The maximum net direct sample result was equal to 2025 dpm/l00 cm2 . The total standard deviation exceeded the design sigma but sufficient samples were taken and variance in the data was relatively small.
When adjusted for background, the mean residual activity is 1399 dpm/l 00 cm2 which is equivalent to 0.023 mrem/y.
Scan surveys resulted in one verified alarm. Repeat survey, including volumetric concrete samples, showed no evidence of plant-derived residual activity.
F. ADDITIONAL DATA EVALUATION While not part of the FSS of this survey unit, LTP commitments (Section 6.6.10) provided for the collection of water samples prior to draining the CWPH bays for FSS. The samples were collected as required and counted to environmental LLD values. None of the samples showed activity at the LLD listed in Table 3.
TABLE 3 WATER SAMPLING LLD VALUES I Nuclide I LLD (uCi/mL)
Mn-54, Co-58, Co-60 <l1.5E-8 Zr-95, Cs-134 <___ ____
Cs-137 <I.8E-8 Fe-59, Zn-65 <3.OE-8 Sediment samples from each of the CWPH bays were taken, consistent with the special provisions of LTP Section 6.6.10. Fourteen samples were collected and counted to Cs-137 environmental LLD values. The average sediment activity was 0.17 pCi/g (Co-60 results were < MDA), much lower than the surface soil DCGL of 4.2 pCi/g (per LTP 6.6.10).
Overall, this result is consistent with background levels and showed no evidence of plant-derived activity over background.
7 Dose = (1399/18000) dpmI1 00 cm2 x 0.301 mrem/y at the DCGL.
FB-I 100-01, Revision 0 Page 5 of 27
As discussed in Section B, removable contamination samples were collected at each direct measurement location. Three smear samples initially indicated positive results when counted by a gas proportional counter in the alpha-only mode. The smears were recounted and analyzed by gamma spectroscopy. A small level of alpha activity (i.e., 3 to 5 dpm/lOOcm 2) was determined to be naturally occurring Th-234.
These additional sampling and analysis measures (water, sediment, and smears) were confirmatory to the FSS and not used directly in the survey unit release decision.
Attachment 4 provides further 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. As is shown in the table, all of the key release criteria (except final sigma) were clearly satisfied for the FSS of this survey unit. The variance between the design and final sigma is discussed in Section E.
- 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 Class 3 survey unit. All of the measurements are well below the DCGL of 18,000 dpm/l 00 cm 2 .
- 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 THE EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class 3 area; the FSS results were consistent with that classification. The direct measurement total sample standard deviation wvas greater than the design sigma. However, a sufficient number of sample measurements were taken to provide adequate power to reject the null hypothesis.
FB-I 100-01, Revision 0 Page 6 of 27
Ii. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of this survey unit was designed, performed, and evaluated in 2001 using, primarily, the criteria of the LTP Revision 2 (Reference 1). LTP changes made subsequent to the completion of this survey were reviewed. These changes were evaluated and found to have no impact on the results or conclusions of this FSS.
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 were less than the DCGL of 18,000 dpm/l 00 cm 2 .
A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied. The total direct measurement sigma was determined to be greater than that used for design; however, a sufficient number of samples was taken to reject the null hypothesis.
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. Scanning resulted in one verified alarm which was investigated with no evidence of plant-derived activity found.
In addition, while not part of the release decision criteria, water and sediment sampling identified no evidence of plant-derived activity over background. Removable contamination sampling indicated no significant loose contamination in the survey unit.
It is concluded that FB-I 100 Survey Unit I met the release criteria of IOCFR20.1402 and the State of Maine enhanced criteria.
FB-1 100-01, Revision 0 Page 7 of 27
J. REFERENCES
- 2. Maine Yankee Engineering Calculation, EC-009-01
- 3. Maine Yankee Engineering Calculation, EC-033-01
- 4. 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
- 5. Maine Yankee, LTP, Revision 2, Maine Yankee letter to the NRC, MN-01-032, August 13, 2001 FB-I 100-01, Revision 0 Page 8 of 27
Attachment 1 Survey Unit Maps FB-1 100-01, Revision 0 Page 9 of 27
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Decommssoning Team Maine Yankee Decommissioning Project Survey Map Map ID# FB 1100-02 Survey Type: I, Characterization T Turnover
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Main Yankee Maine Yankee Decommissioning Project Survey Map MaplD# FB 1100-02A.
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FB-1 100-01, Revision 0 Page 13 of 27
Moaine Yankee Yakec Mainomsn-Yanee Prjp S Map DcommssiningProjctMarveyMap1100-03 ID# FB DeconTssblorna ream Man r~~ ~re Survey Type: , Characterization w- Turnover L Final Status Survey I Survey Area Name: Circ. Water Pump House CON,.
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Maine Yankee DecammlssbnlTeam Maine Yankee Decommissioning Project Survey Map I Map ID# FB 1100-04 SuiveyType: _ Characterization '- Turnover
- FInal Status Survey i SurveyArea Name: Circ. Water Pump House C
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I. i I FB-I 100-0 1, Revision 0 Page 15 of 27
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Maineank~ee Decomm.lsslonna Tea- n Maine Yankee Decommissioning Project Survey Map ; MoplD# FB 1100-06 i Suivey Type: .Charactorization :Turnover
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Attachment 2 Survey Unit Instrumentation FB- 1I00-01, Revision 0 Page 19 of 27
TABLE 2-1 INSTRUMENT INFORMATION E-600 S/N I Probe S/N (type))
1619 148938 (43-68) 1641 148932 (43-68) 1643 148117 (43-68)
HPGe Detectors for Lab Analysis of Volumetric Samples MDC Detector Number (pCilg for solids)
__ (ItCi/mL for liquids)
FSS-I 0.05 to 0.15 pCi/g FSS-2 0.05 to 0.15 pCi/g FSS-1 IE-8 [tCi/mL FSS-2 I E-8 jICi/mL TABLE 2-2 INSTRUMENT SCAN MDC AND COMPARISION WITH DCGL AND INVESTIGATION LEVEL Detector 43-68 Comments Design MDC value from Scan MDC 4859 LTP Table 5-6 at reduced (dpm/100 cm 2) efficiency (LTP Revision 3, Reference 4)
DCGL 18,000 LTP Table 6-11 (dpm/100 cm2)
Investigation Level (Alarm Setpoint) 10,528 Approximately 0.5 DCGL (dpm/I00 cm 2 )
FB-I 100-01, Revision 0 Page 20 of 27
Attachment 3 Investigation Table FB-1 100-01, Revision 0 Page 21 of 27
TABLE 3-1 INVESTIGATION TABLE FB-I 100-01, Revision 0 Page 22 of 27
Attachment 4 Statistical Data FB-I 100-01, Revision 0 Page 23 of 27
Survey Package FB1100 Unit I Surface Sign Test Summary n itVaudsat L i g . . 6 -
Survey Package: FBI100 Circ Water Pumphouse Survey Unit: 01 Evaluator: GP DCGL,: 18,000 DCGLamc: 18,000 LBGR: 9,000 Sigma: 319 Type I error: -- 0.05 Type II error: 0.05 Total Instrument Efficiency: 4.9%
2 Detector Area (cm ): 126 Choosing 'NIA' sets material Material Type: N/A background to "0" Z~g:* . .:1645 Sign p: , 0.99865 Calculated Relative Shift: -
Relative Shift Used: ; 3.0 Uses 3.0 if Relative Shift >3 N-Value: '
N-Value+20%: ______.___________
Number of Samples: -_ ,_he__ i Median: ; 1.388 Mean: - 1,0o3 Net Static Data Standard Deviation: 3-'-.27i Total Standard Deviation: I ,;.522 SRSS Maximum: -, -. 2.028 Adjusted N Value:
S+ Value: , 4 Critical Value: , .
Sufficient samples collected: s Maximum value <DCGL,: . Pass Median value <DCGLw: m i s Mean value <DCGLw: P-iPass Maximum value <DCGL,: Pass Total Standard Deviation <=Sigma: investiget e Section E of Release Record Sign test results: Ra s'7m __
The survey unit passes all conditions: investiet e Section I of Release Record FBI 100-SUI-SurfaceSign FB-1 100-01, Revision 0 10/27/04 11:18 AM Page 24 of 27
FB-1100 SU-1 Quantile Plot 2500 E 2000 0
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- Activity (dpm/1.00 cm2)
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One-Sample T-Test Report Page/Date/Time 2 9/29/04 11:26:49 AM Database C:\Program Files\NCSS97\Fbl 100.S0 Variable C2 Plots Section Histogram of FB-1 100. SU-1 0)t 0.
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FB-I 100-01, Revision 0 Page 26 of 27
One-Sample T-Test Power Analysis Page/Date[Time 2 9/29/04 11:27:59 AM Chart Section Retrospective Power Curve 1.0-0.8- I I I \I .. . _ I I \ I 0.6- .- -r _- _-. - - r. - - -r -
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