ML051050075
| ML051050075 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 04/04/2005 |
| From: | Olsen C, Packer J, Pillsbury G, Randall D, Tozzie R Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FD-3500-04, Rev 0 | |
| Download: ML051050075 (21) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-3500 STORM DRAINS SURVEY UNIT 4
[Prepared By: L-0 fi Date: 2________
FSS Engineer - Signature
_ & t~/o/q HtiJ4(
Printed Name Reviewed By: Date:
FSS S1W Signature Printed Name Reviewed By: Date: 1 L Q*
Indeppdent vciew - Signature Peerinedme Approved By: Date: _Z,/7/,O S,~rneden yEigature 7Printed Namne7 Approved By: ^ M Date: MH
'-FSS,OP - Signature ir Pnted. Name Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-3500 STORM DRAINS SURVEY UNIT 4 A. SURVEY UNIT DESCRIPTION Survey Unit 4 is a portion of Survey Area FD-3500, the Storm Drains survey area. The Storm Drains accommodated the overboard discharge of surface water through buried piping of varying diameters and material types across the developed portion of the site. The survey area consists of Class 1 and Class 3 piping sections. The classification of individual piping sections was based on their potential for contamination, this determination was based primarily on location. The survey classes for particular sections are specified in section 5A of the License Termination Plan (LTP, Reference 1).
Survey Unit 4 consists of storm drain piping in the vicinity of the Warehouse and Fire Pond areas. This included concrete piping upstream of manhole 27 (the SU's system low point) and is designated as Section 7 in the LTP. The survey unit also includes an unconnected section of 8" PVC storm drain line that ran under Warehouse 2/3. This portion of the system is located near grid coordinate 408,000 N and 623,750 E using the Maine State Coordinate System (West Zone) NAD 1927. The associated piping is shown in relation to other major site structures in map FD 3500-4 SITE. All maps referenced in this release record are provided in Attachment I unless otherwise noted. The survey unit is approximately 162.6 m.
B. SURVEY UNIT DESIGN INFORMATION The area was incorrectly designated a Class I piping survey unit per the LTP (Attachment 5A). Due to its location and low potential for containing residual contamination, this section of pipe was reclassified to Class 3 in accordance with the LTP and site procedures.
The survey unit design parameters are shown in Table 1. Given an adjusted relative shift of 3.0, it was determined that 14 direct measurements were required for the Sign Test; however, the number of samples was increased because the LTP also requires a minimum of 30 direct samples points. Therefore, 30 measurements were taken.
A representative portion of the system piping, obtained from the system low point, was excavated and placed in secure storage to accommodate surveys due to accessibility and safety concerns. The lowest elevation of the survey unit is considered to be an appropriate location for sampling, as is suggested by the LTP as a key element of the survey design for Class 3 piping. Measurement locations were randomly distributed over the interior circumference and length of this pipe. The location from which the pipe section was removed is shown on map FD3500-4 REF. The direct measurement locations are illustrated on map FD3500-4b.
FD-3500-04, Revision 0 Page 2 of 21
The survey was also designed to include 16 scan grids for flat surfaces, each of 0.18 m2 area (see map ED 3500-4a) for a total area of 2.9 M2 . This meets the 1% to 10% scan requirement for a Class 3 area. Instrument scan setpoints were approximately set at the DCGL plus background, as shown in Table 2-2 (Attachment 2).
To accommodate measurement geometry requirements for surfaces of differing curvatures, the 43-68 data was evaluated with a reduced surface efficiency of 10.4%, which is appropriate for concrete pipe with an ID of 15" (Reference 5).
Ambient background was established for the 43-68 instrument probe based on local scaler measurements in the survey unit. The average scaler value for background, listed in Table 1, was used to establish net activity for direct measurements. Material backgrounds were not used.
Since scan measurements are performed in peak hold mode, it is appropriate to apply a peak hold background for calculating scan setpoints. The background applied was the peak hold average ambient value used in determining the material background for concrete (622 cpm)
Reference 6.
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.
FD-3500-04, Revision 0 Page 3 of 21
TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Dcsign Criteria Basis Area 162.6 m2 Based on an adjusted LBGR of 8,576 dpm/lOOcm 2 , sigma' of 408 dpm/l00 Number of Direct 30 cm 2 , and a relative shift of 3.0.
Measurements Required N=1 4 for Type I = Type II = 0.05 Minimum = 30 per the LTP Attachment 5A Sample Area N/A Class 3 Sample Grid Spacing N/A Class 3 Scan Grid Area 0.18 m2 6" bands for 15" diameter piping Area Factor N/A Class 3 Scan Survey Area 2.9 m2 (1.8%) Class 3 (1- 10%) required Background . - <
43-68 Direct 2,289 dpr/l00 cm2 Ambient Scaler Value (dry concrete surfaces) 43-68 Scan 4,747 dpr/I00 cm2 Peak hold ambient value (Reference 6)
(dry concrete surfaces)
Scan Investigation Level DCGL plus background See Table 2-2 (Attachment 2)
DCGL 9,800 dpm/I00 cm2 LTP, Rev. 3 Design DCGLEMC N/A Class 3 C. SURVEY RESULTS Thirty direct measurements were made in Survey Unit 4. The direct measurements were less than 50% of the DCGL. The resulting data are presented in Table 2. No verified alarms were received during the surface scans. Therefore, no investigations were required.
I Design sigma is based an averaging of sigma values from selected areas drained in FD 3500.
FD-3500-04, Revision 0 Page 4 of 21
TABLE 2 DIRECT MEASUREMENTS SmlLoainGosActivity Sample Location cm.. Net ActivitySubtracted)
(Table I Background 100 m dpm/1 00 cm 2 FD3500043COOIBD4368 3,396 1,107 FD3500043C002BD4368 4,594 2,305 FD3500043C003BD4368 3,671 1,381 FD3500043C004BD4368 3,800 1,511 FD3500043C005BD4368 3,823 1,534 FD3500043C006BD4368 3,915 1,625 FD3500043C007BD4368 3,442 1,152 FD3500043C008BD4368 3,770 1,480 FD3500043C009BD4368 3,518 1,229 FD3500043COlOBD4368 3,114 824 FD3500043COllBD4368 4,060 1,770 FD3500043C012BD4368 3,312 1,023 FD3500043CO13BD4368 3,365 1,076 FD3500043C014BD4368 3,419 1,129 FD3500043C015BD4368 3,602 1,313 FD3500043C016BD4368 3,770 1,480 FD3500043C017BD4368 3,465 1,175 FD3500043C018BD4368 4,228 1,938 FD3500043C019BD4368 3,900 1,610 FD3500043C020BD4368 3,549 1,259 FD3500043C021BD4368 3,251 962 FD3500043C022BD4368 3,426 1,137 FD3500043C023BD4368 2,991 702 FD3500043C024BD4368 3,938 1,648 FD3500043C025BD4368 3,785 1,496 FD3500043C026BD4368 3,472 1,183 FD3500043C027BD4368 3,365 1,076 FD3500043C028BD4368 3,442 1,152 FD3500043C029BD4368 3,770 1,480 FD3500043C030BD4368 3,724 1,435 Mean 3,629 11,340 Median 3,575 1,286 Standard Deviation 333 333 Sample Range 2,991 to 4,594 702 to 2,305 D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No investigations were required as there were no verified scan alarms and all direct measurements were below 50% of the DCGL.
FD-3500-04, Revision 0 Page 5 of 21
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 less than 50% of the DCGL. The maximum direct sample result with background subtracted was equivalent to 2,305 dpm/l 00 cm2 .
When adjusted for background, the mean of the direct measurements is 1,340 dpm/l 00 cm 2 .
This is equivalent to an annual dose of 0.0004 mrem2 .
There were no verified alarms, and therefore there were no investigations.
F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with Survey Unit 4, 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 Sign Test Summary table calculated the total standard deviation by propagating the individual standard deviation values used in the subtracted background survey design (using the square root of the sum of the squares method). Therefore, median, mean, and standard deviation values listed in the Sign Test Summary table are slightly different from those listed in Table 2. These differences, however, are minor and have no impact on the statistical analysis or conclusions.
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, except for the final sigma exceeding the design sigma, all of the key release criteria were clearly satisfied for the FSS of this survey unit. The difference in sigma values is discussed further in Section G.
- 2. The Quantile Plot was generated from direct measurement data listed in Table 2 and indicates general symmetry about the median. 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 concrete surface survey unit. It also should be noted that the maximum net activity (2,305 dpm/1 00 cm 2 at location C002) is well below 50% of the DCGL of 9,800 dpm/100 cm 2 .
2 From table 6-1 1 of the LTP, the buried piping dose is 2.52E-03 mrem/y, therefore, (1,340/9,800) x 2.52E-03 =
0.0004 mremly.
FD-3500-04, Revision 0 Page 6 of 21
- 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 showvs 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 area; the FSS results were consistent with that classification. The direct measurement sample standard deviation was less than the design sigma. The total standard deviation was essentially equal to the design sigma (408 dpm/100 cm vs 409 dpm/100 cm 2 ). Thus, a sufficient number of sample measurements were taken.
H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 4 was designed and performed using the criteria of the approved LTP (Revision 3 Addenda). The only subsequent LTP changes (with potential impact to this FSS) were provided in the proposed license amendment related to modifications of the activated concrete remediation plan submitted September II, 2003 (Reference 4). Changes represented in this later proposed license amendment have been evaluated and have no impact on the design, conduct, or assessment of the final status survey of Survey Unit 4.
I. CONCLUSION The FSS of this survey unit was designed based on the reclassified 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 beta direct measurements were less than the DCGL of 9,800 dpm/l00 cm2 .
A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied. The direct measurement total sigma was determined to be essentially equal to 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 variance consistent with expectations for 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 a no verified alarms. Since there were no alarms, no investigations were required.
It is concluded that FD-3500 Survey Unit 4 meets the release criteria of I OCFR20.1402 and the State of Maine enhanced criteria.
FD-3500-04, Revision 0 Page 7 of 21
J. REFERENCES
- 1. Maine Yankee License Termination Plan, Revision 3, October 15,2002
- 2. Maine Yankee letter to the NRC, MN-02-061, dated November 26,2002
- 3. NRC letter to Maine Yankee, dated February 28, 2003
- 4. Maine Yankee letter to the NRC, MN-03-049, dated September 11,2003
- 5. Maine Yankee Calculation EC-010-01
- 6. Maine Yankee Calculation EC-039-01 FD-3500-04, Revision 0 Page 8 ofM2
Attachment 1 Survey Unit Maps FD-3500-04, Revision 0 Page 9 of 21
I I~
cnD CDO 0
o 0a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0(0 0
_ _ _ __ __ 623 .000 EC C 3
_______ 62:3.500 CD~
0- 624. 000 C
-n-POINTC )~ DC
___ ______ __ __ ___ __ ___ __ __ __ ___ -626. 000 C cf 3CD~
- 0) 0 CD 625,000C UI(
ISLAND .) 0 Note Grd baed Sste n Mane tateCoodinae (West5one) ND 192 GRAPHI SCAL
Maine Yankee mavip iu *; ruaz~UU-Q Decommissioning Team IMaine Yankee DecomnnissioningProject Sun'ey Forn IDate:3/7/05 Survey Type: E Characterization 0 Turnover X Final Status Survey I Survey Area Name: Yard Storm Drains and Outfalls Final Status Survey FD3500 SU4: Yard Storm Drains and Outfalls Pipe Location Reference FIRE POND U
/
\
\
CONTAINMENT
Maine Yankee I . I Map ID #:FD3500-4a Decommissioning Team lMaie YankeeDecotommissioninig ProjectSt'rveyForm Date: 1/25105 Survey Type: EJ Characterization E Turnover 1 Final Status Survey ISurvey Area Name: Yard Storm Drains and Outfalls Final Status Survey FD3500: Yard Storm Drains and Outfalls Survey Scans COOl - C016 00 90g 180° 2700 3 60O l I C016 C015 C014 C013 0 C012 Top of Pipe Coil (Position 0°)
Colo C009 COOS C007 C006 C004 180° End View C003 Opposite Bell-End 46 _ __ _ _
C002 Cool End of Pipe 3600 270' 1800 900 End of Pipe Top of Pipe-(0°, Arbitrary)
FD-3500-04, Revision 0 Page 12 of 21 Total Scanned Area = 2.92 sq-m Isometric View
Maine Yankee Map ID #: FD3500-4b Decommissioning Team Maine Yankee DecommissioningProjectSurvey Form Revised: 1125/05 Survey Type: E Characterization LI Turnover S Final Status Survey I Survey Area Name: Yard Storm Drains and Outfalls Final Status Survey FD3500: Yard Storm Drains and Outfalls Direct Points C001 - C030 Top of Pipe (Position 00) 0 C'4 End View Opposite Bell-End End of Pipe FD-3500-04, Revision 0 50 Page 13 of 21
Attachment 2 Survey Unit Instrumentation FD-3500-04, Revision 0 Page 14 of21
TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN i Probe SIN (type) 2489 177991 (43-68-5)
TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Detector 1 43-68 15"dia. dr surfaces Scan MDC 2,290 (dpmrln00 cm2) (Note I)
DCGL 9,800 (dpm/1 00 cm2 )9,0 Investigation Level 14,545 (Alarm setpoint) DCGL plus background)
(dpm/l 00 cm 2) (Note 2)
NOTES: 1. Separate scan MDC developed for the 43-68 when applied to the pipe geometry by adjusting the LTP Table 5-6 value for the change in efficiency.
- 2. The survey was initially designed and implemented using an efficiency for flat concrete (0.13) which resulted in an investigation level of 1,900 cpm. This instrument setpoint corresponded to a level which would have exceeded the DCGL + background when the curved concrete efficency was applied (0. 104).
However, when the setpoints were re-evaluated, it was found that by using a peak hold ambient background (622 cpm) and a curved efficiency (0.104) the setpoint stands at approximately 1,900 cpm. All measurements were less than the investigation level shown in Table 2-2.
FD-3500-04, Revision 0 Page 15 of 21
Attachment 3 Investigation Table (No Investigations Required)
FD-3500-04, Revision 0 Page 16 of 21
Attachment 4 Statistical Data FD-3500-04, Revision 0 Page 17of21
Survey Package FD3500 Unit 4 Surface Sign Test Summary Survey Package: FD3500 Class 3 piping Survey Unit: 04 Storm Drain piping Evaluator: DR DCGLw: 9,800 DCGLemc: 9,800 N/A Class 3 LBGR: 8,576 Sigma: 408 Type I error: 0.05 Type II error: 0.05 Total Instrument Efficiency: 10.4%
Detector Area (cm2 ): 126 Choosing 'N/A' sets material Material Type: N/A background to "0"
" '.-.: -calculatdA.>¢T
-Valu'esi'! !7me r m Zl,: 1.645 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 _I N-Value+20%: . 14
,'3;,,j,*,H ,Static D'ataValu^ 4K,0\
-... - i e H'I')Cmn Number of Samples: 30 Median: ' 1,28i Mean: 1,335 Net Static Data Standard Deviation: 333 Total Standard Deviation: 409 SRSS Maximum: 2,300
,~~ dd-'l>,41' t ~gn Tost Resut4-<' s+ j a z <I'mrn'nfi;;
OI Adjusted N Value:- 30 S+ Value: , ' 30 Critical Value: . .20 Sufficient samples collected: ;Pass Maximum value <DCGLE,:Pass Median value <DCGLt: Pass Mean value <DCGLw: ' Pass Maximum value <DCGL,,,: Pass N/A Class 3 Total Standard Deviation <=Sigma:
- Investigate Satisfactory see section F Sign test results: ; . - ' Pass The survey unit passes all conditions: . nvestigate SU passes FD3500-Su4-SurfaceSign FD-3500-04, Revision 0 314105 9:07 AM Page 18 of 21
FD-3500 SU-4 Quantile Plot 2500 E 2000 0
0 w ._ 1500
- Activity (dpm/1 00 cm2) 0 00 E
0.
0 V
" 0 * *
- IV - Median (dpm/100 D
%%MO 1000 cm2)
A:
00 4-.
C.,
500 -
0 0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 2/7/05 7:52:33 AM Database Variable C2 Plots Section Histogram of FD-3500, SU-4 en C,
E F)M 0
.0 E
Activity (dpr/100 crm2)
FD-3500-04, Revision 0 Page 20 of 21
One-Sample T-Test Power Analysis Page/Date/Time 2 2/7/05 7:53:06 AM Chart Section Retrospective Power Curve 1.0- 0-
- I 0.8- I I
I
- I a).
0.6- * -
I I
- 0)
- I I I 0-0.4- - --- I
- I I
- I I I I I I I
- I I 0.2- --II
- I I I I
- I 0.0 IC)00 3d00 50'00. 700)0 9doo ii boo Survey Unit Mean (dprn/100 cm2)
FD-3500-04, Revision 0 Page 21 of 21