ML043500357
| ML043500357 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 12/07/2004 |
| From: | Pillsbury G Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FR-0230-01, Rev 0 | |
| Download: ML043500357 (18) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0230 XIA AND X1B TRANSFORMER SURVEY UNIT 1 Prepared By: _ { "5 s Date: L/C.
d ndent iew gnature Printed Name/
Reviewed By: 1 Date: 1l- zZ-FSS ecialist - Signature Printed Name Reviewed By: CALm u Independent Review -,..Signature Date: ;C.I
, C. APJ&I Approved By: m eDate: 14171/0:
SdrntenntSt~pgnature 7Printed Name7 Approved By: ,K~ 04 Date: -"7/vz
"~FSS, MOP - Signature Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0230 X1A AND X1B TRANSFORMER SURVEY UNIT 1 A. SURVEY UNIT DESCRIPTION FR-230 is the survey area located in the Industrial Area to the east of the Turbine Building where the XIA and XIB transformers were located. The survey area is located at approximate coordinates 407,500 N and 624,250 E using the Maine State Coordinate System (West Zone) NAD 1927, and is shown on map FR 0230-LOC. All maps referenced in this release record are provided in Attachment 1 unless otherwise noted.
The survey area is comprised of one survey unit. Survey Unit I is the post demolition structural remnant of the transformers' concrete foundation. The remnants consisted of a rectangular slab with partial walls on the north and west sides. The survey unit area is approximately 672 m .
B. SURVEY UNIT DESIGN INFORMATION The survey area was located outside of the Restricted Area of the plant in the east yard. The survey unit consisted of concrete walls and floor of the rock-filled pit upon which the main station transformers sat. There was no history of surface or airborne contamination, and there were no cross-contaminated systems residing in, or traversing through this area. The concrete was demolished to the 17-foot elevation and the rocks removed prior to survey. The area was designated as a Class 3 survey unit. Surveys were biased to the floor.
The survey unit design parameters are shown in Table I below. Given a relative shift of 3.0, 14 direct measurements were required for the Sign Test. The direct measurement locations were randomly generated. The location of the direct points are shown on map FR0230-2.
Once the direct readings were completed, removable contamination samples were also obtained at each measurement location.
For a Class 3 area, a 1% to 10% scan coverage is required. This was accomplished by scanning a 2.2 m x 2.2 m grid around each direct measurement location. The scan grid locations are shown on map FR0230-1.
FR-0230-01, Revision 0 Page 2 of 18
TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria J Basis Area 672 m2 No limit for Class 3 Area Based on an adjusted LBGR of Number of Direct Numbe of 16,704 cm 2 , sigma dpm.l 00 c2ana 432rect10 lI Measurements Required 14 of 432 dpm/l0O cm and 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 2.2m x 2.2m Class 3 Area Area Factor N/A N/A Scan Survey Area 67.8 mZ Class 3 Area> 1% - 10%
Background . - -; '.:
43-68 Direct and Scan 3,028 dpm/100 cm} Ambient plus Material Scan Investigation Level DCGL + background See Table 2-2 (Attachment 2)
DCGL 18,000 dpm/100 cm 2 LTP, Revision 3 Addenda Design________ __ N(Reference 1)
Design DCGLEMC N/A Class 3 Area 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 and the investigation level. As shown in this table, the scan MDC is less than the scan investigation level in all cases, thus providing high confidence (95% or higher) that an elevated area would be detected in the scanning process.
Background values were established for the instrument probe based on ambient background values in the survey unit and previously established material backgrounds. The background value, listed in Table 1, was used to establish net activity for direct measurements, scan alarm setpoints, and to confirm the scan MDCs used were appropriate.
C. SURVEY RESULTS Fourteen direct measurements were made in Survey Unit 1. All direct measurements were less than the DCGL. The resulting data are presented in Table 2 below. No verified scan alarms were encountered during the survey.
Design sigma is based on characterization data, listed in LTP Table 5-IB, for adjacent Administration Building, B1200 (LTP, Revision 3)
FR-0230-0 1, Revision 0 Page 3 of 18
TABLE 2 DIRECT MEASUREMENTS Gross Activiy Net Activity Sample Number 2tIy (dpm/100 cm) l (dpm/100 cm)2 FRO230013COO1BDOOOO 3071 43 FR0230013C002BDOOOO 3254 226 FR0230013C003BDOOOO 3156 128 FR0230013C004BDOOOO 3284 256 FRO230013COO5BDOOOO 3297 269 FRO230013CO06BDOOOO 3333 305 FRO230013CO07BDOOOO 3632 604 FR0230013C008BDOOOO 3480 452 FR0230013C009BDOOOO 3370 342 FR0230013CO1OBDOOOO 3864 836 FR0230013CO 11BD0000 3230 201 FRO230013CO12BDOOOO 3315 287 FR0230013C013BDOOO l 3974 946 FRO230013CO14BDOOOO 3846 818 Mean 3436 408 Median 3324 296 Standard Deviation 283 283 Range 3.071 - 3974 62 - 946 D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS There were no verified alarms when scanning the survey area and no investigations were needed.
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 direct sample result with background subtracted was equivalent to 946 dpm/1 00 cm 2 . When adjusted for background, the mean residual contamination level was 408 dpm/100 cm 2 . This would be equivalent to an annual dose of 0.007 mrem. 2 2 This annual dose equivalent is based on LTP, Table 6-11 that shows the contaminated concrete dose contribution (for surfaces contaminated at the DCGL) to be 0.301 mrem/y.
FR-0230-01, Revision 0 Page 4 of 18
F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with Survey Unit 1, 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 Class 3 survey unit. There is no reason to conclude that the data set represents other than random variations in a Class 3 survey unit. It also should be noted that the maximum net activity (946 dpm/1 00 cm 2 at location C01 3) is 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.
- 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.
As mentioned in Section B, removable contamination samples were obtained at each (direct) measurement location. In that this survey unit involved a (backfilled) pit and not a standing building, the removable contamination measurements were not applicable to release decisions for the survey unit. However, the samples were obtained and evaluated, indicating alpha and beta activity less than the MDA values (i.e., < 19.7 dpm/100 cm2 alpha; < 14.2 dpm/1 00 cm2 beta). Thus, in comparison with the mean survey unit net activity (Table 2),
the removable contamination sampling effort indicated that the majority of activity is fixed.
G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class 3 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.
FR-0230-01, Revision 0 Page 5of 18
- 11. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit I was designed and performed using the criteria of the approved LTP, Revision 3 Addenda (Reference 1). The only subsequent LTP changes were provided in the proposed license amendment related to modifications of the activated concrete remediation plan submitted September 11, 2003 (Reference 2). Changes represented in this later proposed license amendment have been evaluated and have no impact on the design, conduct, or assessment on the final status survey on Survey Unit 1.
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 .
A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied. The direct measurement sigma wvas determined to be less than that used for design, thus indicating that a sufficient number of samples were 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 variance consistent with expectations of a Class 3 survey unit.
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 no verified alarms for evaluation.
In addition, while not part of the release decision criteria, removable contamination sampling confirmed that the majority of remaining activity in this survey unit was fixed.
It is concluded that FR-0230 Survey Unit I meets the release criteria of IOCFR20.1402 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-02-06 1, dated November 26, 2002
- 2. Maine Yankee letter to the NRC, MN-03-049, dated September 1, 2003 FR-0230-01, Revision 0 Page 6 of 18
Attachment 1 Survey Unit Maps FR-0230-01, Revision 0 Page 7 of 18
Maine Yankee Maine Yankee DecommissioningProjectSurvey Form Map ID #: FR 0230-LOC Decommissioning Team MI e Survey Type: O Remediation C Turnover j0 Final Status Survey I Survey Area Name: FR 0230, Transformer 1A & 1B Pit 623,000 E 623.500 E 624.000 E
MN 0 400 800 1200 S===. M
_N-500-ft GRID BASED ON MAINE STATE COORDINATE SYSTEM (WEST ZONE) NAD 1927 FR-0230-01, Revision 0 Page 8 of 18
Maine Yankee , Map ID #:
Decommissioning Team Aiai!ie Yankee DccoiuimissioningP l Survey o FR0230-1 Survey Type: Characterization : - Turnover X Final Status Surve
- X 1A--y X1ThScan(rd Ae 3Name:
X1A and X1B Transformers -f-*'- N Concrete Scan Locations 30
\\Turbine Building Slab 25 20 E 15 10 5
0 CO I II II I I I 11H1i I I- I I I I I 0 5 10 15 20 25 X Axis (m)
FR-0230-01, Revision 0 Page 9 of 18 Scan areas 2.2 m x 2.2 m
Maine Yankee a. , Map ID #:
Decommissioning Team ! r I, FRO230-2 Survey Type: Characterization . Turnover X Final Status Survey Survey Area NmIe LXIAK&X1BRSLAR X1A and XI B Transformers I %N Concrete Direct Locations 30 I Turbine Building Slab \
C014 C012. 22,27 14,26 C013 A)18,25 C011-25 Coil 23,23 4.
\
20 C008 C009 2,18 :. 3,10 Colo
.A 20,17 a)
C002 Cool
- >%.-7,1 6 16,17 C007 C003 I-, 0I x 15 4,14 11,15 '>r co ,,. - .fl
= C004 I C005 (0
2,14 (9=)
-(-- 18,12 C006
, 8, 1 0 10 5 I 0,0 0
,C-) - - - -
I I 5I I I II 11 20I I 121 0 5 10 15 20 25 X Axis (m)
FR-0230-01, Revision 0 Page 10 ofl8 Coordinates XXXX - Measured North, West form 0,0 point in meters
Attachment 2 Survey Unit Instrumentation FR-0230-01, Revision 0 Page II of IS
TABLE 2-1 INSTRUMENT INFORMATION 1
I E-600 SIN Probe S/N (type) 2488 J 148934 (43-68) 1622 J 149071 (43-68) l 2488 149073 (43-68) _J TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Detector 1 43-68 l Comments I Scan MDC 1832 LTP Table 5-6 (dpm/l 00 cm2 )18,000 Investigation Level 21,000 (Alarm Setpoint) (- DCGL plus Background)
(dpm/100 cm 2 )
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Attachment 3 Investigation Table (None Required)
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Attachment 4 Statistical Data FR-0230-01, Revision 0 Page 14 of 18
Survey Package FR0230 Unit I Surface Sign Test Summary
< .. ;>r-.":.rlEva uation nputai's a,,,,¢+,,,,,-1 ',:
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Survey Package: FR0230 Main Transformer Pad Survey Unit: 01 Evaluator: GP DCGL,: 18,000 DCGLemc: NA LBGR: 16,704 Sigma: 432 Type I error. 0.05 Type II error: 0.05 Total Instrument Efficiency: 13.0%°/
Detector Area (cm 2 ): 126 Concrete Choosing 'N/A' sets material Material Type: Unpainted background to "0'
'..;.>#.--t.,-l¢,:i H , ues.......-
C i ua ...t'as-.- ?-; ;.- . ' m I t9 r2C Zo: 1.645 Z1.0: 1.645 Sign p: 0.99865 Calculated Relative Shift: 3.0 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift >3 N-Value: 11 N-Value+20%: 14 m
'"a'ValUes,?' C. Cofmnts- ?i Number of Samples: 14 Median: 297 Mean: 410 Net Static Data Standard Deviation: 283 Total Standard Deviation: 334 SRSS Maximum:- 948
> ;l ~
Test Results!> ? ,'; - >j '....
?m Comment ',V;.
Adjusted N Value: 14 S+ Value: 14 Critical Value: 10 r 'i ' < ' ' r fi er J a itrsf aCt , Pi> >_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _-2 Sufficient samples collected: Pass _ _
Maximum value <DCGL,,: Pass Median value <DCGL,,: Ps Mean value <DCGLw- Pass Maximum value <DCGL., - -'Pass Total Standard Deviation <=Sigma: Pass Sign test results: - ,'Pass heL surveiynuitp a o.ditions 'Pstss, -
Thne survey unit passes all conditions:l ' .';Pass_________________
FR0230-SU1-SurfaceSign FR-0230-01, Revision 0 12/7104 9:48 AM Page 15 of 18
FR-0230 SU-1 Quantile Plot 1000 900 E 800 110 0 700 0w 0 600
- Activity (dpm/100 cm2)
O 0
-~ 6 E 500 i:.
00 vs *0 -Median (dpm/100 400 0 cm2)' ____I
- 300 A
_ _ F. ........
IV 4-f C. 200 100 0 i 0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 11/30/04 8:00:25 AM Database C:\Program Files\NCSS97\FR0230 SU-1.S0 Variable C2 Plots Section Histogram of FR-0230, SU-1 0)
E
-0 3E z
FR-0230-01, Revision 0 Page 17 of 18
One-Sample T-Test Power Analysis Page/DatelTime 2 11/30/04 8:01:32AM Chart Section Retrospective Power Curve 1.0- p',
0.8-I
) I (D
0.4 - _ - ---
.* . I 0.0I l 0 5d00 1o6oo 15600 20600 Survey Unit Mean (dpm/100 cm2)
FR-0230-01, Revision 0 Page 18 of 18