ML090850562
| ML090850562 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 09/29/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097 | |
| Download: ML090850562 (22) | |
Text
Rancho Seco Final Status Survey Summary Report September 29, 2008 Railway External to the IA Survey Unit F8340021 Prepared By: Dan A. Tallman -Date: September 29, 2008 FSS Engireer Reviewed By:_______ ___ Date: f(IIo7 (o, Lead FSS Engineer Approved By: Date:
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:.
F8340021, Railway External to the IA Survey Unit
Description:
Operating History: The rail spur passes through two sections of the Non-Impacted portion of the site before entering the Industrial Area. The rail system was used to transport radioactive material from the site to the out of state waste disposal facilities.
Even though the packages met DOT requirements for shipment, there is the potential for a small amount of contamination to be deposited along the rail right of way. There were no reports of rail contamination in the HSA and no documented, operational surveys showing evidence of contamination along the rail spur external to the Industrial Area.
Site Characterization: Soil samples were collected along the rail line and analyzed by gamma spectroscopy on site. The mean value was 0.073 pCi/g Cs-137 and the maximum was 0.114 pCi/g. Based on classification procedure (DSIP-0020) and the characterization survey data, the rail spur was classified as Class 3.
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 randomly determined and 728 m2 were scanned for approximately 12%
coverage. Gamma Direct measurements were taken at each direct measurement location and analyzed with ISOCS / GAA. 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 F8340021
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area: F834 Railway External to the IA Survey Unit: 0021 Open Land Area Class: 3 LTP Table 5-4 SU Area (m2): 5990 Evaluator: D.A.Tallman DCGL Cs137 surrogate (pCi/g): 51.2 Area Factor: N/A Class 3 Design DCGLemc (pCi/g): N/A Class 3 LBGR (pCi/g): 51.1 Adjusted Design Sigma (pCi/g): 0.018 DTBD-06-001, Table 5-4B Type I Error: 0.05 Type II Error: 0.05 Nuclide: Cs137 Sample Area (m2): N/A Class 3 Total Area Scanned (m2 ): 728 Scan Coverage (%): 12.2% Class 3 Z1 .*: 1.645 ZI-0: 1.645 Sign P: 0.99865 Calculated Relative Shift: 5.5 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: N/A Class 3 Page 3 of 7 FSS Summary Report F8340021
Survey Results:
A total of 16 direct measurements were made in F8340021. The results including mean, median, standard deviation and range are shown in Table 2. All of the direct measurements were less than the DCGL. None of the scan measurements indicated areas of elevated activity with observed activity below the MDA (0.225 pCi/g Co60, 0.299 pCi/g Cs 137). Gamma Direct measurements 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: 8.47E-01 Median: 8.55E-01 Standard Deviation:$ 7 7.66E-02 _________
Range: 6.11 E-01 to 9.19E-01 F8340021 ROOO1GD 9.09E-01 < 9.09E-01 F8340021 R0002GD 8.82E-01 < 8.82E-01 F8340021 R0003GD 9.19E-01 < 9.19E-01 F8340021 R0004GD 9.17E-01 < 9.17E-01 F8340021 R0005GD 9.09E-01 < 9.09E-01 F8340021 R0006GD 6.11E-01 < 6.11E-01 F8340021 R0007GD 8.28E-01 < 8.28E-01 F8340021 R0008GD 8.88E-01 < 8.88E-01 F8340021 R0009GD 8.72E-01 < 8.72E-01 F8340021 ROO1OGD 9.04E-01 < 9.04E-01 F8340021 ROO11GD 8.24E-01 < 8.24E-01 F8340021 R0012GD 8.28E-01 < 8.28E-01 F8340021 R0013GD 8.38E-01 < 8.38E-01 F8340021 R0014GD 8.25E-01 < 8.25E-01 F8340021 R0015GD 8.23E-01 < 8.23E-01 F8340021 R0016GD 7.73E-01 < 7.73E-01 Page 4 of 7 FSS Summary Report F8340021
Survey Unit Data Assessment:
The survey design required 16 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 greater than the design standard deviation however, both values result in a relative shift greater then 3.0 so no additional samples were required.
Page 5 of 7 FSS Summary Report F8340021
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N): 16 Median (pCi/g): 8.55E-01 Mean (pCi/g): 8.47E-01 Standard Deviation (pCi/g): 7.66E-02 Maximum (pCi/g): 9.19E-01 Sign Test Final N Value: 16 S+ Value: 16 Critical Value: 11 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: N/A Class 3 Standard Deviation <= Sigma: Investigate Both values result in relative shifts greater than three therefore, no additional sample measurements necessary.
Pass the Sign Test? Yes Reject the Null Hypothesis? Yes The survey unit passes all conditions? Yes Page 6 of 7 FSS Summary Report F8340021
Survey Unit Investigations and Results:
No investigations were required for either direct or scan measurements and no investigation results are reported.
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 3 land survey and the sample results are consistent with that classification. The variability of the survey results was greater than the characterization data used for survey design. Both values result in a relative shift greater than three, therefore no additional sample are required. No potential areas of elevated activity were detected.
==
Conclusion:==
The FSS of this survey unit was properly designed as a Class 3 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. No investigations were required.
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 F8340021 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F8340021
Attachment 1 Maps September 29, 2008 Survey Unit F8340021
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Approximate surface area-5990 mn from cattle guard at property line to gate #2 Key Plan N~ K Gate #2
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Point to North- East-point South West 1 Ste na 142.3 1-2 64' S 64' E r~i~ 2-3 64'S 128' E 4 64' S 64' E 4,5 64' S 128' E 5-6 &61'S 64'E 6-7 128' S 64' E 7-8 320' S 0' Cattle guard @ property line 8-9 192'S 61' )XI 9-10 128' S 64' W 10-11 128' S &1"W 11-12 128' S 64' W 12-13 64' S 0' 13-14 64'S 0' 14-15 64'SS '
15-16 64'S 0' 00 w) Scale: 1/128" = 1.0' NON-INDUSTRIAL AREA RAILWAY Meter Scale GAMMA DIRECT 0 5 12 15 24 30 60
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MEASUREMENT LOCATIONS IUT El DI' 1CT A F8340021-M2 FI'IE: 810001 SHEET 3 of4 TC HILL
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17'1 00 Scale: 11128" = 1.0' w NON-INDUSTRIAL AREA RAILWAY Meter Scale GAMMA DIRECT 0 5 12 18 24 3) 60 -" MEASUREMENT LOCATIONS SA1R.AMEENT'_i MUNICIPAL LITHITY DISTRICT F8340021-M2 FliE: 81000b SHEET 3 of4 TC HILL I
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/ /7i026 Gamma Scan locations 17-26 will be located at 100' intervals - all scan locations will be centered between the rails.
ý7r1 00 C.) Scale: 1i128"= 1.0' NON-INDUSTRIAL AREA RAILWAY Meter Scale ISOCS GAMMA SCAN 0 6 12 V3 24 30 60 WSmUD MEASUREMENT LOCATIONS EDO MUNICIPAL UTILITY DISTR..CT F8340021-M3 FI.E: 610001 SHEET I of2 TC HILL
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(,z Key Plan Gamma Scan locations 1-10 will be located at 50' intervals - scans 11-17 will be located at 100' intervals - all scan locations will becentered betweenthe rails.
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00 Scale: 1V128" = 1.0' W NON-INDUSTRIAL AREA RAILWAY Co 0 612 Meter Scale IS24 30 60 I=F, smuc .A.-AS NAMMUICIPALi ISOCS GAMMA SCAN MEASUREMENT LOCATIONS UTILTY DISTRiC'*
F8340021-M3 810001 8WO: SHEET 2 of2 TO HILL
Attachment 2 Instrumentation September 29, 2008 Survey Unit F8340021
Table 2-1. Survey Unit Instrumentation Detector Detector Serial Instrument Model MDC No.No.
Soil - 0.919 pCi/g Cs-137 Soil - 0.919 pCi/g Co-60 ISOCS N/A 1983920 Soil -0.299 pCi/g Cs-137 1 1_ 1 Soil - 0.225 pCi/g Co-60 Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value Soil - 20 pCi/g Cs-137 ISOCS Investigation Criteria - Scan Soil - 2 pCi/g Co-60 Soil - 5 pCi/g Co Inspector Investigation Criteria - Direct Soil- 51.2 pCi/g Cs-137(surr.)
All DCGLw 51.2 Cs-137 12.6 Co-60 All DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8340021
Attachment 3 Investigation September 29, 2008 Survey Unit F8340021 (none required)
Page I of I Att. 3 Investigation
Attachment 4 Data Assessment September 29, 2008 Survey Unit F8340021
0Q F8340021 Quantile Plot Cs137 DCGL = 51.2 pCi/g 1.000 0.900 0.855 0.800 (D
0.700 U
0.600 0.
0.500 CD 0.400 0.300 0.200 0.100 0.000 0 20 40 60 80 100 Percentile I* Activity - Median - - - 75th Percentile - - - -50th Percentile I C)
aQ C
F8340021 Scatter Plot Cs137 DCGL 51.2 pCiIg tZI 1.20E+00
.j* -- - -- -- - - -- - - - - - - - - - - - - - - - - -- 1.077 1.00E+00 0 0 0 . 0 S8.OOE-01 * ' - - 6- 0
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.4 6.00E - .0................ . 0.617 t 4.OOE-01 2.OOE-01 0.00E1+00 w 4.O+0 nc$ (ý SO x I *
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Measurement Locations o Activty - Average - -+3StDev" "-3SiDer" 00
-1e:
0 F8340021 Frequency Plot Cs1 37 DCGL = 51.2 pCi/g 9
8 7
6 LL 5 0
4 M3 (tD 3
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2 1
0 N N N N N N oc NY N Co. 'VCo Co Bins - Upper End Value (pCi/g)