ML090830541
| ML090830541 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/10/2009 |
| From: | Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097, F8000011 | |
| Download: ML090830541 (17) | |
Text
Rancho Seco Final Status Survey Summary Report February 10, 2009 Folsom Intake, Helo Pad, South Scrap Yard Combined Survey Survey Unit F8000011 Revision I Prepared By: . X Date: 2-T'O -OZ FSS Engineer Reviewed By: Date: 7-Lead FSS Engineer Approved By: ____ _____Date:________
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F800001 1, Folsom Intake, Helo Pad, South Scrap Yard Combined Survey Survey Unit
Description:
Operating History: The E-W corridor in the Industrial Area was located to the north of the rail spur between the cooling towers and the power block. Included in this survey unit were all the concrete and asphalt roads, the concrete berm beside the road, the raised area next to the cooling tower pipe cradle structure, and the asphalt/concrete pads remaining from the demolition of the Contractor Fab Shop (ident:,fied as 853000 in the HAS and is summarized below). Operating records and the HSA document several nearby leaks or spills with the potential for a release of radioactivity associated with this survey area. The HSA documented the storage of radioactive material within the area that may have had the potential to contaminate the area.
Site Characterization: The pavement was surveyed. Measurements taken on the asphalt and concrete surfaces showed a mean level of 3,664 dpm/100 cm2 and a maximum of 7,175 dpm/100 cm2. Based on the classification procedure (DSIP-0020) and low levels of Cs-137 reported, the area was determined to be a Class 2 land area.
HSA Events: LER-7505, 8304, 8335.
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 1131 m2 were scanned !:'or approximately 7%
coverage. Soil samples were collected at each direct measuremenrt location and analyzed by HPGe detector. 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 F8000011
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area: F800 Folsom Intake, Helo Pad, South Scrap Yard Combined Survey Survey Unit: 0011 Open Land Area Class: 3 LTP Table 5-4 SU Area (m2): 17284 Evaluator: Gary Frank DCGL Cs137 surrogate (pCi/g): 52.6 Area Factor: N/A Class 3 Design DCGLemc (pCi/g): N/A Class 3 LBGR (pCi/g): 26.3 Default = 50% DCGL Design Sigma (pCi/g): 0.1 DrBD-06-001, Table 5-4B Type I Error: 0.05 Type II Error: 0.05 Nuclide: Cs137 Sample Area (m2): N/A CIAass 3 Total Area Scanned (m2): 1131 Scan Coverage (%): 6.5% Class 3 1.645 Zi-P 1.645 Sign P: 0.99865 Calculated Relative Shift: 263 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 F8000011
Survey Results:
A total of 14 direct measurements were made in F800001 1. 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. 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: 4.97E-0 1 .
Median:~ 7.96E-0 I Standard Deviation: Y, 3.94E-01 Range: 4.56E-02 to 8.74-E-01 F8000011AO001GD 8.16E-01 < 8.16E-01 F8000011A0002GD 8.01E-01 < 8.01E-01 F800001IA0003GD 8.20E-01 < 8.20E-01 F8000011A0004GD 7.91E-01 < 7.91E-01 F800001IA0005GD 8.20E-01 < 8.20E-0l F8000011A0006GD 8.70E-01 < 8.70E-0I F800001 1A0007GD 8.03E-01 < 8.03'E-01 F8000011A0008GD 8.74E-01 < 8.74E-01 F8000011SOOO1SS 5.16E-02 < 5.16E-02 F8000011SO002SS 4.56E-02 < 4.56E-02 F8000011S0003SS 6.88E-02 < 6.88E-02 F8000011S0004SS 5.79E-02 < 5.79E-02 F8000011S0005SS 7.40E-02 < 7.40E-02 F8000011SO006SS 5.81E-02 < 5.81E-02 Page 4 of 7 FSS Summary Report F8000011
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 greater than the design standard deviation but both values of sigma resulted in a relative shift greater than three (3), no additional samples were required.
Page 5 of 7 FSS Summary Report F8000011
Table 3. Data Assessment Results Survey Results PFarameter, Value Comment Actual Direct Measurements (N): 14 Median (pCi/g): 7.96E-01 Mean (pCi/g): 4.97E-01 Standard Deviation (pCi/g): 3.94E-01 Maximum (pCi/g): 8.74E-01 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: N/A Clas 3 Standard Deviation <= Sigma: Investigate Results <0.5 DCGL Pass the Sign Test? Yes Reject the Null Hypothesis? Yes The survey unit passes all conditions? Investigate Survey unit passes Page 6 of 7 FSS Summary Report F8000011
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, 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. 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 F8000011 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F8000011
Attachment 1 Maps May 13, 2008 Survey Unit F8000011
0 OoI 00 C:
C)
CD
0 Note: Distance from 01GS to 07GS is 130'. 06GS to 08GS is 130'... To 40GS E6812687 N1888084 E6812687 N1888007
--. 4-. E6813848
- i. N1887848 E6812812 N1887842 2
Total scan area -1120m which equals 6.5%
It1 SOUTH WESTERN IA GO. ISOCS SCANS F8000011 - M2
Attachment 2 Instrumentation May 13, 2008 Survey Unit F8000011
Table 2-1. Survey Unit Instrumentation Detector Detector Serial Instrument Model No.MDC No.
HPGe N/A 05069128 Soil- 0.0456 pCi/g Cs-137 Inspector N/A 08051294 Asphalt - 0.791 pCi/g Cs-137 Soil - 0.15 pCi/g Cs-137 ISOCS N/A 2983947 Soil -0.136 pCi/g Co-60 Asphalt- 0.248 pCi/g Cs-137 Table 2-2. Investigation Criteria and DCGL Instrument Parameter 'Value Soil - 26.3 pCi/g Cs-137 ISOCS Investigation Criteria - Scan Soil - 6.3 pCi/g Co-60 Asphalt - 2.6.3 pCi/g Cs-137 All DCGLw 52.6 Cs-137 All_ _ DCG__w12.6 Co-60 Page 2 of 2 PAtt. 2 Instrumentation F8000011
Attachment 3 Investigation May 13, 2008 Survey Unit F8000011 (none required)
Attachment 4 Data Assessment May 13, 2008 Survey Unit F8000011
F8000011 Quantile Plot Cs137 DCGL = 52.6 pCi/g 1.200 1.000 0.800 0.796 0.600
(~1
- 0. 0.400 00 .5 0.200
(.)
0.000
-0.200
,0.400 C)2
-0.600 0 20 40 60 80 100 Percentile I + Activity - Median - - -75th Percentile - - - - 50th Percentile I
CD w F8000011 Scatter Plot 0
C$137 DOOL = 52.6 pCIIg 2.OOE+00 1.50E+00
>~2 1%OOE+00 U 0 0 0
(-.4 p .00E-0~1 - - - - - - - a* 0.49- Q 0 0 0 0 Ln O000E+00
-5.OOE-O1 LIUUL:+UUP 00 Measurement Locations Ave a ge "+3 St Dev" "-3 St Dev".
CD~
F8000011 Frequency Plot Cs1 37 DCGL = 52.6. pCi/g 9
8 7
0D 6-LL 5-0 4-3-
(I) 0 2
..2 00 1
C> 0-_
C)
& N . Q
&vj t~IL Bins - Upper End Value (pCi/g)