ML090830316
| ML090830316 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/09/2008 |
| From: | Ellen Brown Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097, F8000091 | |
| Download: ML090830316 (21) | |
Text
Rancho Seco Final Status Survey Summary Report April 9, 2008 South East Industrial Area Survey Unit F8000091 Prepared By: 2 / Date: 4 9 ZO2)8 FSS Eg eer Reviewed By: Date: 41/j Lead SS Engineer, Approved By: Date: _______
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8000091, South East Industrial Area Survey Unit
Description:
Operating History: This area covers the majority of Industrial Area soils exclusive of the building footprints and rail line in this area. Operating records and the HSA document no specific release of radioactivity in these survey areas however this area does border known contaminated areas. The HSA recorded no specific unplanned release events.
Site Characterization: Soil and sediment samples were collected and analyzed for the presence of plant-derived radionuclides. Cs-137 was the only detected nuclide of plant origin with a mean activity level of 0.062 pCi/g and a maximum value of 0.299 pCi/g.
(Site background levels of Cs-137 have been determined to be approximately 0.312 pCi/g.) As described in section 2 of the LTP, the area was evaluated using DSIP-0020 and was designated 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 (which consisted of both soil samples and asphalt measurements) were randomly determined and 2346 m2 were scanned for approximately 4% coverage. Soil samples were collected at each direct measurement location and analyzed by HPGe detector. The instrumentationused for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.
Page 2 of 8 FSS Summary Report F8000091
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area: F800 South East Industrial Area Survey Unit: 0091 Open Land Area Class: 3 LTP Table 5-4 SU Area (m2): 55736 Evaluator: Erin L. Brown DCGL Cs137 surrogate (pCi/g): 52.6 Area Factor: N/A Class 3 Design DCGLemc (pCi/g): N/A Class 3 LBGR (pCi/g): 25.6 Adjusted Design Sigma (pCi/g): 0.042 DTBD-06-001, Table 5-4D Type I Error: 0.05 Type II Error: 0.05 Nuclide: Cs137 Sample Area (m2): N/A Class 3 Total Area Scanned (m2): 2346 Scan Coverage (%): 4.2% Class 3 ZJ., : 1.645 Zi-P : 1.645 Sign P: 0.99865 Calculated Relative Shift: 642.8 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 8 FSS Summary Report F8000091
Survey Results:
A total of 30 direct measurements were made in F8000091. The results including mean, median, standard deviation and range are shown in Table 2. All of the direct measurements were less than the DCGL. Noneof the scan measurements indicated areas of elevated activity. Soil samples were counted to the MDC shown in Table 2-1 of .
Table 2. Direct Measurement Results (all activity values in pCi/g)
Measurement ID Cs137 MDA Cs137 Activity Uncertainty Mean: :4.65E-01 Median:6.66E-01I Standard Deviation: 3.66E-01 Range: 6.14E-02 to 8.96E-01 F8000091 AOOOlGD 7.57E-01 < 7.57E-01 F8000091 A0002GD 8.25E-01 < 8.25E-01 F8000091 A0003GD 8.22E-0l < 8.22E-0l F8000091 A0004GD 6.87E-01 < 6.87E-01 F8000091 A0005GD 8.72E-01 < 8.72E-01 F8000091 A0007GD 8.96E-0.1 < 8.96E-01 F8000091 A0008GD 8.14E-01 < 8.14E-01 F8000091 A0009GD 8.30E-01 < 8.30E-01 F8000091 AOO1OGD 8.57E-01 < 8.57E-01 F8000091 A0012GD .8.34E-01 < 8.34E-01 F8000091 A0013GD 8.42E-01 < 8.42E-01 F8000091 A0015GD 8.36E-01 < 8.36E-01 F8000091 A0016GD 8.21E-01 < 8.21E-0l F8000091 C0006GD 7.18E-01 < 7.18E-01 F8000091 COO11GD 7.06E-01 < 7.06E-01 F8000091CO014GD 6.44E-01 < 6.44E-01 F8000091SOOOISS 6.92E-02 < 6.92E-02 F8000091S0002SS 6.61E-02 7.96E-02 4.44E-02 F8000091S0003SS 9.16E-02 < 9.16E-02 F8000091S0004SS 9.24E-02 < 9.24E-02 F8000091S0005SS 6.40E-02 < 6.40E-02 F8000091SO006SS 8.46E-02 < 8.46E-02 F8000091SO007SS 6.14E-02 < 6.14E-02 F8000091SO008SS 8.94E-02 < 8.94E-02 F8000091S0009SS 6.82E-02 1.09E-01 4.05E-02 F8000091SO010SS 6.16E-02 7.01E-02 4.73E-02 F8000091SO011SS 6.29E-02 < 6.29E-02 F8000091S0012SS 8.84E-02 < 8.84E-02 Page 4 of 8 FSS Summary Report F8000091
F8000091SO013SS 6.98E-02 < 6.98E-02 F8000091SO014SS 5.07E-02 1.57E-01 5.88E-02 Page 5 of 8 FSS Summary Report F8000091
Survey Unit Data Assessment:
The survey design required 30 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 of sigma result in a relative shift of greater than 3 so no additional samples were required.
Page 6 of 8 FSS Summary Report F8000091
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N): 30 Median (pCi/g): 6.66E-01 Mean (pCi/g): 4.65E-01 Standard Deviation (pci/g): 3.66E-01 Maximum (pci/g): 8.96E-01 Sign Test Final N Value: 30 S+ Value: 30 Critical Value: 20 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 No additional samples required Pass the Sign Test? Yes Reject the Null Hypothesis? Yes The survey unit passes all conditions? Investigate The survey unit passes Page 7 of 8 FSS Summary Report F8000091
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. However, no additional samples were 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 F8000091 meets the release criteria of IOCFR20.1402.
Page 8 of 8 FSS Summary Report F8000091
Attachment 1 Maps April 9, 2008 Survey Unit F8000091
I I
I I1 I
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-22100 So m W0I/G0RVEL Fii]
I 5813735.75E 5 15 25 1 M79WC.0BN 26642 50 M METERS ASP~kLT/CONCRETE 00 (55m)
SOUTHEAST INDUSTRIAL AREA SURVEY AREA F8000091 -M1
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CIO SOUTHEAST INDUSTRIAL AREA
[SOCS FIELD OF VIEW, 28 m 2
0 5 10 15 SCALE 20 25 0 SMUn SAC*AMENTO MUNCIPAL UTILIY DISTRICT GAMMA SCAN LOCATIONS F8.000091 -M2 METERS
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00 SOUTHEAST INDUSTRIAL AREA 2
GAMMA SCAN LOCATIONS ISOCS FIELD OF VIEW, 28 m SA. MENTO MUCIPAL 0 5 O 15 SCALE METERS 20 25 UTILIY DISTRICT F8000091 -M3 RC RAYMOND FiLFj go o~
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(-A fi Ig)
III n i6 0 5 10 15 20 25 SCALE METERS 00 SOUTHEAST INDUSTRIAL AREA ISOCS FIELD OF VIEW, 28 M 2
WRAMENTO MUNICIPAL GAMMA SCAN LOCATIONS UTLITY DiSTRICT F8000091 -M4
ON 00 C3=1 5 15 2:5 METERS 0-0 SOUTHEAST INDUSTRIAL AREA GAMMA DIRECT MEASUREMENT &
w S USOIL SACRAMENTO MUNCIPAL SAMPLE LOCATIONS F8000091 -M5 UTILITY DISTRICT FILL, 80009 RC RAYMOND
Attachment 2 Instrumentation April 9, 2008 Survey Unit F8000091
Table 2-1. Survey Unit Instrumentation.
Detector Detector Serial Instrument Model No.MDC No.N HPGe 'N/A 9987008 Soil -0.06 pCi/g Cs-137 HPGe N/A 05047773 Soil - 0.09 pCi/g Cs-137 N/A 08051294 Concrete 0.7 pCi/g Cs-137 Asphalt - 0.8 pCi/g Cs-137
- Soil - 0.3 pCi/g Cs-137 Soil - 0.1 pCi/g Co-60 Asphalt - 0.3 pCi/g Cs-137 Concrete- 0.4 pCi/g Cs-137 Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value Soil - 23 pCi/g Cs-137 ISOCS investigation Criteria - Scan Soil - 5.7 pCi/g Co-60 Asphalt - 23 pCi/g Cs-137 All DCGLw 52.6 Cs-137 12.6 Co-60 All DCGLEMc N/A I Page 2 of 2 Att. 2 Instrumentation F8000091
Attachment 3 Investigation April 9, 2008 Survey Unit F8000091 (none required)
Attachment 4 Data Assessment April 9, 2008 Survey Unit F8000091
CD O
F8000091 Quantile Plot Cs137 DCGL = 52.6 pCi/g 1.000 0.900 0.800 0.700 0.666 0,
U 0.600 0.
0.500
.5 CD2 Li 0.400 0.300 0.200 0
0.100 0
0.000 0 20 40 60 80 100 Percentile I* Activity - Median - - - 75th Percentile - - - - 50th Percentile 00 002
CDQ F8000091 Scatter Plot F8000091 Scatter Plot CS137 DCGL = 62.6 pCIlg CD 2.00E+00 1.662 1.50E+00 -------------------------------------------------
1.00E+00 0o0 0 0 0 0 0 0
,*5.00E-01 0.465 00
- .OOE+00 0000000000000.
-5.O0E-01 - 0.632
-1.00E+00 ii iI.
C/)
Cd)
CD Cd)
Measurement Locations 0 Activity - Average - - "+3StDev" - - "-3StDev"
CD F8000091 Frequency Plot Cs137 DCGL = 52.6 pCi/g 13 12 11 10 9
U) 8 LL 7
-r-0 6 00 5
4 3
2 1
0 bo.
Bins - Upper End Value (pCi/g)