ML043290357
| ML043290357 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 11/17/2004 |
| From: | Randall D Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FD-0500-02, Rev 0 | |
| Download: ML043290357 (18) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-0500 CIRCULATING WATER PIPING SURVEY UNIT 2 Prepared By: 3A Date: P-Z O el FSS Engineer - Signature P !t e ZC ta A/--
Printed Name Reviewed By: _____ -Date: _ _ 95 /o el FSS pecialist - Signature Printed Name Reviewed By: . Date:
Independent Review -
Signature Approved By: Date: /.0/z peitenAt, FSS - 1 S, ature rint d Name Approved By: Date:
FSMOP - signature Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-0500 CIRCULATING WATER PIPING SURVEY UNIT 2 A. SURVEY UNIT DESCRIPTION FD-0500 Survey Unit 2, the Circulating Water Piping, consists of the interior portions of the buried outlet pipes that conducted non-radioactive condenser cooling water overboard from the Turbine Building. The four outlet pipes were 72" ID as they exited the condenser. Two pairs of outlet pipes were joined to form two common 102" ID discharge headers. Portions of the two discharge pipes were steel lined concrete pipes, while the remaining pipe sections were constructed of concrete. Refer to map FDO500-5 in Attachment 1 for pipe location and detail. While the system was located inside the Industrial Area of the site, it was considered to be outside of the plant's radiologically restricted area (RA). The survey unit area is shown in relation to other major site structures in map FD0500-5. All maps referenced in this release record are provided in Attachment 1, unless otherwise noted. The survey unit's total area is approximately 2277 M2 .
B. SURVEY UNIT DESIGN INFORMATION FD-0500 Survey Unit 2 was designated a Class 3 survey unit per the LTP (Table 5-4E).
The survey unit design parameters are summarized in Table 1. A minimum of 30 direct measurements were required in accordance with the LTP, Attachment 5A. The start point for the direct measurement locations was the 0 degree point when facing the pipe opening and direct measurements were also taken at 90, 180 and 270 degree positions in each end of each pipe. The sample points were located as shown in the attached maps (FDO500-5 and FDO500-6, Attachment 1).
A 1% to 10% scan coverage of the area was required.' Scan areas were typically 2 m bands and were located as shown on survey map FDO500-06, Attachment l. The total scan area was approximately 32 m2 (1.4% area coverage).
The survey instruments used, their MDC values and alarm setpoints, are provided in Attachment 2. As shown in this attachment, the scan MDC is less than the scan investigation level in all cases, thus providing high confidence (95% or greater) that an elevated area would be detected in the scan process.
When background measurements were made, it was found that the outlet pipe background (347 cpm) was higher than the discharge header background (189 cpm). The discharge headers sat within the seal pit area which was below grade and surrounded by ledge on three sides which effectively shielded the area. The lowest ambient background value (189 cpm) was used for both locations and no material backgrounds were used even though one set of pipes was steel and one was concrete.
LTP Table 5-3 FD-0500-02, Revision 0 Page 2 of 18
TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit J Design Criteria J Basis Area 2277 m2 Internal area, based on pipe length and ID.
Based on LBGR of 4900 Number of Direct Minimum of 30, per LTP dpmi/100 cm 2 , sigma2 of Measurements Required Attachment 5A 727 dpm/1 00 cm2 , and 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 2 m x 2 m bands around Scan Grid Spacing circumference of pipe opening east Class 3 Area and west ends Area Factor N/A Class 3 Area Scan Survey Area 32 m2 Class 3 Area: 1 - 10%
Background ___ _________;_____________
Ambient (the lower set of 43-68 Direct and Scan 455 dpm/100 cm 2 steel pipe backgrounds were used)
(flat surfaces) 2 1154 dpm/Il 00 cm concrete pipe No material backgrounds were used.
Scan Investigation Level - DCGL for concrete EC-009-01 (Reference 1)
See Table 2-2 _ _ _ _ _ _ _ _ _ _ _ _
lDCGL 9,800 dpm/100 cm lLTP Revision 3 Addenda l 90 (References 2, 3, and 4)
Design DCGLaic N/A Class 3 Area C. SURVEY RESULTS Thirty-two direct measurements were made in Survey Unit 2. The direct measurement results are presented in Table 2 below. All direct measurements were less than the DCGL.
No alarms were received during scanning; therefore, no investigations were required.
2 LTP Table 5-lB, B0500 Turbine Building FD-0500-02, Revision 0 Page 3 of 18
TABLE 2 DIRECT MEASUREMENTS
- Gross Activity l Net Activity' Sample Number (dpm/100 cm2 ) l (dpm/100 cm2 )
FD-0500-02-P001 933 479 FD-0500-02-P002 928 474 FD-0500-02-P003 991 536 FD-0500-02-P004 1260 806 FD-0500-02-P005 1154 700 FD-0500-02-P006 919 464 FD-0500-02-P007 1130 676 FD-0500-02-P008 1085 630 FD-0500-02-P009 1041 587 FD-0500-02-P010 1000 546 FD-0500-02-P011 991 536 FD-0500-02-P012 1015 560 FD-0500-02-P013 984 529 FD-0500-02-P014 1082 628 FD-0500-02-POI5 1142 688 FD-0500-02-P016 991 536 FD-0500-02-P017 1056 -98 FD-0500-02-P018 995 -159 FD-0500-02-P019 1081 -73 FD-0500-02-P020 916 -238 FD-0500-02-P021 989 -165 FD-0500-02-P022 867 -287 FD-0500-02-P023 1056 -98 FD-0500-02-P024 965 -189 FD-0500-02-P025 1081 -73 FD-0500-02-P026 1172 18 FD-0500-02-P027 1136 -18 FD-0500-02-P028 1136 -18 FD-0500-02-P029 1087 -67 FD-0500-02-P030 916 -238 FD-0500-02-P031 1178 24 FD-0500-02-P032 1081 -73 Mean 1042 238 Median 1049 244 Standard Deviation J 93 365 Range 867- 1260 -287-806 3 Two survey unit background values were used to calculate net activity, based on location. The lowver of these two values (189 cpm) was subtracted from the gross activity results reported here, which is conservative. Two different efficiencies were also used (one for concrete, one for steel) which caused the difference in standard deviations in Table 2.
FD-0500-02, Revision 0 Page 4 of 18
D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No investigations were required.
E. SURVEY UNIT DATA ASSESSMENT RESULTS An analysis of the direct sample measurements, including the mean, median, standard deviation, and sample result range, are provided in Table 2. Both the mean and the median activities were less than the DCGL. The maximum net direct measurement result was 8% of the DCGL.
When the Table I background values are subtracted from the sample measurements for the survey unit, the result is a mean net value of 238 dpm/l 00 cm 2 . This would be equivalent to an annual dose rate of 6.12E-05 mrem/y 4 .
F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with Survey Unit 2, 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 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 survey unit similar to a Class 3 basement. It also should be noted that the maximum net activity (806 dpm/l 00 cm2 at location P004) is well below the DCGL of 9,800 dpmrl100 cm2 .
- 3. A Histogram Plot was also developed based on the direct measurement values. The statistical analysis of this direct data indicated that normality was questionable. It is, therefore, concluded that the data essentially represents a bimodal distribution, due to the two background values present at the two ends of the pipe.
4 This annual dose equivalent is based on LTP Table 6-1 1, which shows the buried pipe dose contribution (for surfaces contaminated at the DCGL) is 0.00252 mremly.
FD-0500-02, Revision 0 Page 5 of 18
- 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 ("powier") 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.
A small portion of the planned scan area was found to be wet; however, the dry surfaces provided sufficient area to meet the scan design value. After background subtraction there is no effect on the survey results even if a reduced efficiency for damp concrete is used.
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 final sigma was less than the design sigma and no additional samples were required.
H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 2 was designed, performed and evaluated in late 2003 and early 2004.
The design was performed to the criteria of the LTP, Revision 3 Addenda (References 2, 3 and 4). There are no LTP changes requiring evaluation.
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 9800 dpm/I00 cm 2 .
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 bimodal 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 no verified alarms; therefore, no investigations were required.
It is concluded that FD-0500, Survey Unit 2, met the release criteria of IOCFR20.1402 and the State of Maine enhanced criteria.
FD-0500-02, Revision 0 Page 6 of 18
J. REFERENCES
- 1. Maine Yankee Engineering Calculation, EC-009-01
- 2. Maine Yankee License Termination Plan, Revision 3, Maine Yankee letter to the NRC, MN-02-048, dated October 15, 2002
- 3. Maine Yankee License Termination Plan, Revision 3 Addenda, Maine Yankee letter to the NRC, MN-02-06 1,dated November 26, 2002
- 4. NRC letter to Maine Yankee, dated February 28, 2003, Approval of LTP Rev. 3 and Addenda FD-0500-02, Revision 0 Page 7 of 18
Attachment 1 Survey Unit Maps FD-0500-02, Revision 0 Page 8 of 18
FinalStatusSirvey I MineaYankee ID# FDO500-5 PreedBy: Larry N. Dockins Date: 12/15/03 Suvey Type: Final Status Survey IA, B, C & D Condenser Outlets (Turb. Bldg) lSurveyArea Name: FD 0500 Buried Piping (Clrc. Wtr.)
623,700 E 623,800 E 623,900 E 624,000 E 624,100 E
-p ACf I
B2vey Final Status F SSu=y uvDecommissioning a
Team MapeID#
Discharg I
FDO500-6 P lPe-PoedBy Larry N. Dockins Date: 12/15/03 12m15 SmwvTyT'pe: Final Status Survey East and West Discharge (Seal-PT) survey Area Name: FD 0500 BUred Piping (Clrc. Wtr.)
Direct Measurment Location (lYP) f -Scan Grid (lYP)
)90 18 00 270° rLoi P01 P02 P023 n wV P018 P020 P022 P0241 n
<- 2.035m >< 2.035m "I, 2.035m I 2.035m >
00 900 160P 270° P025& P027-7 P029 P03 11 P
[P0261 P028] P0301 P0320 FD-0500-02, Revision 0 Pap-e 10 of 18
Attachment 2 Survey Unit Instrumentation FD-0500-02, Revision 0 Page 11 of 18
TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN I Probe S/N (type) 2619 1 148934 (43-68)
TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Detector [ 43-68 (flats) 722 (steel)
Scan MDC 1832 (concrete)
(dpm/100 cm 2) LTP Table 5-6 (Value adjusted for metal efficiency)
DCGL980 (dpm/100 cm2 )9,800 Investigation Level 9,158 (Alarm Setpoint) DCGL)
(dpm/lOO cm2)
FD-0500-02, Revision 0 Page 12 of 18
Attachment 3 Investigation Table (None Required)
FD-0500-02, Revision 0 Page 13 of 18
Attachment 4 Statistical Data FD-0500-02, Revision 0 Page 14 of 18
Survey Package FD-0500 Unit 2 Surface Sign Test Summary I
FD0500-SU2-SurfaceSign.xls FD-0500-02, Revision 0 11/111/04 9:30 AM Page 15 of 18
FD-0500 SU-2 Quantile PLot 910 710 E
- +
0 C
510 + Activity (dpm/100 cm2) 0' C 0 E 310 -Median (dpm/1 00 0
C 3%-0 cm2) 110
- 6-0 U: .. I I
-90 I) *25 50 75 10
-290 Percent
One-Sample T-Test Report Page/Date/Time 2 11/11/04 8:59:40 AM Database C:\Program Files\NCSS97\FD0500SU2.S0 Variable C2 Plots Section Histogram of FD-0500, SU-2 10.000.
co' 7.500.
E , .'s cn 7*V 00
'a 5.000.
.0 E
z 2.500:
n n 4600ooo -6o0o.o 3oooo0 ao 6 ooo a00'1ood.000 Activity (dpm/100 cm2)
FD-0500-02, Revision 0 Page 17 of I8
One-Sample T-Test Power Analysis Page/DatelTime 2 11111/04 9:00:48 AM Chart Section Retrospective Power Curve 1.0- x e-_-_______-___
I I \ I I I 0.8 - - - - i- - - - - I - - - - -- - -
0.6-a) 0.4 --- ------------- --- ------------- I II I l\ I 0-4-- - - --- - I t--
I
-- - - --I I
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- - - - - I - \I I \I 0.2- I
- 4_______
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I Survey Unit Mean (dpm/100 cm2)
FD-0500-02, Revision 0 Page ISofIS