ML090830542
| ML090830542 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/16/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097, F8000104 | |
| Download: ML090830542 (23) | |
Text
Rancho Seco Final Status Survey Summary Report October 16, 2008 Pump Alley Access Corridor Survey Unit F8000104 Prepared By: Dan A. Tallman , _ Date: October 16, 2008 FSS Eng neer Reviewed By: te: (0 712- /62 Lead FSS Engineer Approved By: I-- Date: i?
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8000104, Pump Alley Access Corridor Survey Unit
Description:
The Survey Unit consists of the asphalt pavement between the Auxiliary Building and the T&R building. Packaged demolition debris from the AB pump alley remediation has routinely been transported through the survey unit via the access plug posing the potential for a small amount of contamination to be deposited within the survey unit. During routine surveillance surveys; documented evidence of contamination (single particle 0.05 uCi Co60) adjacent to the pump alley access plug was discovered. This isolated area of contamination and the increase potential in the immediate vicinity resulted in the area being designated as a unique survey unit (8000104).
Site Characterization: Paved areas were surveyed and found to have a mean value of 2,261 dpm/100 cm 2 and a maximum of 3,930 dpm/100 cm 2 . Based on classification procedure (DSIP-0020) and the discovery made during the surveillance survey, the pump alley access corridor between the T&R and Auxiliary buildings is a class 1 area.
Survey Unit Design Information:
The Survey Unit Design Parameters are presented in Table- 1 below. The survey unit and measurement, locations are depicted on the maps in Attachment 1. Direct measurement locations were determined using a random-start, fixed grid pattern and 248 m2 were scanned for 100% coverage. Direct gamma spectrum were collected at each direct measurement location and analyzed by ISOCS. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.
Page 2 of 7 FSS Summary Report F8000104
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area: F800 Pump Alley Access Corridor Survey Unit: 0104 Open Land Area - Paved Class: 1 LTP Table 5-4 SU Area (m2): 248 Evaluator: D.A.Tallman DCGL Cs137 surrogate (pci/g): 51.2.
Area Factor: 1.9 Class 1 Design DCGLemc (pCi/g): 97.8 Class 1 LBGR (pCi/g): 49.49 Adjusted Design Sigma (pCi/g): 0.57 DTBD-06-001, Table 5-4C (expressed in pCi/g)
Type I Error: 0.05 Type II Error: 0.05 Nuclide: Cs137 Sample Area (m2): 17.7 Class 1 Total Area Scanned (m2): 248 Scan Coverage (%): 100% Class 1 Zl-, : 1.645 ZI-p : 1.645 Sign P: 0.99865 Calculated Relative Shift: 44.9 Relative Shift Used: 3 Uses 3.0 if Rel Shift >3 N-Value: 11 Design N-Value + 20%: 14 NUREG-1575 Table 5-5 Grid Spacing L: 4.2 Class 1 Page 3 of 7 FSS Summary Report F8000104
Survey Results:
A total of 14 direct measurements were made in F8000104. The results including mean, median, standard deviation and range are shown in Table 2. All of the direct measurements were less than the DCGL. Three scan measurements indicated areas of elevated activity. Scan measurements ranged from 10,146 cpm to 11,639 cpm. Direct Measurement samples were counted to the MDC shown in Table 2-1 of Attachment 2.
Table 2. Direct Measurement Results (all activity values in pCi/g)
Measurement ID Cs137 MDA Cs137 Activity Uncertainty Mean.:~> 1.04E00 Median:v; 1,04E00 Standard Deviation: 4.30E-02 _________
Range: 9.77E-01 to 1.09E00 F8000104 AOO01GD 1.04E00 < 1.04E00 F8000104 A0002GD 1.02E00 < 1.02E00 F8000104 A0003GD 1.03E00 < 1.03E00 F8000104 A0004GD 9.89E-01 < 9.89E-01 F8000104 A0005GD 9.77E-01 < 9.77E-01 F8000104 A0006GD 9.82E-01 < 9.82E-01 F8000104 A0007GD 1.03E00 < 1.03E00 F8000104 A0008GD 1.09E00 < 1.09E00 F8000104 A0009GD 1.08E00 < 1.08E00 F8000104 A0010GD 9.84E-01 < 9.84E-01 F8000104 A0011GD 1.07E00 < 1.07E00 F8000104 A0012GD 1.09E00 < 1.09E00 F8000104 A0013GD 1.06E00 < 1.06E00 F8000104 A0014GD 1.09E00 < 1.09E00 Page 4 of 7 FSS Summary Report F8000104
Survey Unit Data Assessment:
The survey design required 14 direct measurements for the Sign Test. The critical value and the results of the Sign Test are presented in Table 3. The sample mean and median values were less than the DCGL. The sample standard deviation was less than the design standard deviation so no additional samples were required.
Page 5 of 7 FSS Summary Report F8000104
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N): 14 Median (pci/g): 1.04E00 Mean (pCi/g): 1.04E00 Standard Deviation (pCi/g): 4.30E-02 Maximum (pci/g): 1.09E00 Sign Test Final N Value: 14 S+ Value: 14 Critical Value: 10 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: Yes Class 1 Standard Deviation <= Sigma: Yes Pass the Sign Test? Yes Reject the Null Hypothesis? Yes The survey unit passes all conditions? Yes Page 6 of 7 FSS Summary Report F8000104
-Survey Unit Investigations and Results:
Three investigations (scan grids 03, 09, & 10) were required for the scan measurements and the results are reported in Attachment 3. The EMC unity rule was not exceeded as shown in Table 3-1.
ALARA Statement:
As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit is less than the DCGL (i.e. the survey unit average activity is less than the DCGL and the EMC criterion has been met), the ALARA criterion has been met.
Changes in Initial Survey Unit Assumptions:
The survey unit was designed as a Class 1 land survey and the sample results are consistent with that classification. The variability of the survey results was less than the characterization data used for survey design. Potential areas of elevated activity were detected and evaluated as shown in Attachment 3. Therefore the EMC criterion was met.
Conclusion:
The FSS of this survey unit was properly designed as a Class 1 survey based on Table 5-4 of the LTP. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the LTP. All of the direct measurements were less than the DCGL. The investigations required were performed and evaluated as detailed in attachment 3.
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.
It is concluded that survey unit F8000104 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F8000104
Attachment 1 Maps October 16, 2008 Survey Unit F8000104 j
YARD KEY PLAN 9E6814239 E681ý4.2. a N1888820 886 E6813442 z b N1888650N/
N IE;86 E81814 50* E6814152
- 4s217 rx*31 NI 855 l 8633 E 81423 N18886Z6 N1888782
\m8885551888517 EE61817E442321 E 6813 5546148 6848 08 N18886Nt888382 N1888382 NI888382 N1888382 E 5 SACRAMENTO MUEICIAL1 SCALE UTILITY DISTRICTF0O14-M1 METERS FILE:800010 PACI cf Z RC RAYMOND
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00 IA ACENTRA' YARD N18887f9 INtg88817"------
E6132 E6814239 E68.13442.- N1888820 E68113313 N18886508 rA -1 6E6814153 a1588814 N188863 N1N1888743~ N1E6814239-00000F0000i04 E6E613631 FBO13217 EX00D 000 N18886 E68140622 N1888162 0 *N11888517 E6187E5B132207 WooBE68135 00 E881 3442ý E 442CEU13495 EE813799 E681'480 06814080 N1888382 N1888 42 N188 382 N1888382 SCALE UTILIY DISTRICT *F80001 04-6M1 METERS ARRANGECENT MEESFIILE: 800010 PAUF 9 of -i RC RAYMOND
00 KEY PLAN O0 00 0 Surface Area Estimates PUMP ALLEY ACCESS CORRIDOR
- mn 0 Asphalt 248 m2 0
248 m2 GENERAL ARRANGEMENT Total 0* SURFACE AREA ESTIMATE SACRAMENTO MUNICIPAL UTILITY DISTRICT F8000104-Mi
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C) 00 KEY PLAN f14 FELL OUTSIDE SUID BOUNDARIES R 14 LOCATED WITHIN I METER OF DESIGNATED RANDOM LOCATION 47/8.5 SELECTED AS REPLACEMENT ON 9/20/2008
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Or1 00 PUMP ALLEY ACCESS CORRIDOR SACRAMENTO MUNICIPAL DIRECT MEASUREMENT LOCATION DETAIL F8000104-M2 UTILITY DISTRICT F8 2
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-t 00 KEY PLAN r1 PUMP ALLEY ACCESS CORRIDOR ISOCS GAMMA SCAN osmu*
SACRAMENTO MUNICIPAL LOCATION DETAIL UTILITY DISTRICT F80001 04-M3
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Attachment 2 Instrumentation October 16, 2008 Survey Unit F8000104
Table 2-1. Survey Unit Instrumentation Instrument Detector Detector Serial MDC Model No. No.
Asphalt Inspector N/A 08051294 1.09 pCi/g Cs-137 1.14 pCi/g Co-60 Instrument Detector MDC Model; Serial No. Model; Serial No.
M2350; 193715 44-10; 171374 5.26 pCi/g' Based on DTBD 05-12, Attachment 8.7 (w/ detector 2" above survey surface) 9000 cpm background.
Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value Investigation Criteria - Asphalt - 51.2 pCi/g Cs- 137(SUr.)
Inspector Direct Asphalt - Detectable Co-60 All DCGLw 51.2 pCi/g Cs-137(sur.)
12.6 pCi/g Co-60 All DCGLEMC 97.8 pCi/g Cs-137(surf.)
2 Based on the mean background plus 3 standard deviation for a count rate of 11,200 cpm.
(901]cpm + 3 * (60 (9011/60)A 0.5) = ll,217cpm)a a DSIP-05 10, enclosure 8.6 Page 2 of 2 Att. 2 Instrumentation F8000104
Attachment 3 Investigation October 16, 2008 Survey Unit F8000104
Table 3-1 Survey Unit Investigation T DCGLemc Investigation Initial Value Investigation Elevated Area DCGLeo Investigation Fractn Grid Level (CPM) (CPM) Result Area (m2) Factor Result (pCi/g) Unity (pci/g) Fato 03 11,200A 11,366 1.01/1.03B NA NA NA < DCGLw 0 09 1 1 ,2 0 0 A 11,639 1.09/1.08B NA NA NA < DCGLw 0 10 1 1 ,2 0 0 A 11,299 1.07/1.06B NA NA NA < DCGLw 0 Survey Unit Remainder DCGL = SU Mean =
51.2 1.04 EMC Unity Sum N/A A 11200 cpm (conservative approximation of 11,217 cpm as calculated JAW DSIP-0510 encl. 8.6)
B InSpector 1000 2x2 Nal MDA Co60/Cs 137 Page 2 of 2 Att. 3 Investigation F8000104
Attachment 4 Data Assessment October 16, 2008 Survey Unit F8000104
F8000104 Quantile Plot Cs137 DCGL = 51.2 pCi/g 1.100 1.080 1.060
(-)
1.040 1.035 3
C.,
1.020
('D 1.000 0.980 0.960 0 20 40 60 80 100 Percentile
- Activity - Median - - 75th Percentile - - - 50th Percentile
.ITI 00
(D F8000104 Scatter Plot Cs137 DCGL = 51.2 pCiIg 1.40E+00 CD 1.20E+00 - ------------------------------------------- -15?
0-C O 00 1.OOE+00 .. . .. . . . . .
o o-
. . . . . . . . )909 C 8.00E-O1
- 6.OOE-01 Wj < 4.OOE-01 2.00E-01 0.002+00 Measurement Locations 0 Activity - Averaae - - "+3StDev. - - -3StDev-I 00
I CD 0*
F8000104 Frequency Plot Csi 37 DCGL = 51.2 pCi/g 6
C:
TUg4 c3 U-0 (U
S2 0
N 0XQ0 &0 x X,
N qz(ý Bins - Upper End Value (pCi/g) 41