ML081580579
| ML081580579 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/12/2008 |
| From: | Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| F8480018 | |
| Download: ML081580579 (19) | |
Text
Rancho Seco Final Status Survey Summary Report March 25, 2008 Retention Basin Concrete Storage Survey Unit F8480018 Prepared By.Q1K Date:_______
FSSSEnngi e r Reviewed By:
A Date:
3 4:
LeadzASS Engineer Approved By:
Date:_______
.Dismantlement 9-*Perintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8480018, Retention Basin Concrete Storage Survey Unit
Description:
Operating History: This area is located at the southwest corner of the site. The area surrounds the structures that were used for containment and final treatment of liquid effluents prior to their release from the site. Contaminated resin was reported to have been found in the basins. Operating records and the HSA document occurrences of radioactive material with the potential for a release of radioactivity associated with this survey area. Records confirmed the presence of radioactive material within the area and basin sediment/soil contamination levels up to -290 pCi/g. In addition, soil contamination levels up to '--5 pCi/g prior to some decontamination activities.
Site Characterization: Soil samples were collected and showed Cs-137 at mean activity levels of 0.086 pCi/g and a maximum activity of 0.196 pCi/g. Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the soil area around the asphalt was determined to be Class 3.
HSA Events: LER-8812.
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 283 m2 were scanned for approximately 27% coverage. Soil samples were collected at each direct measurement 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 8 FSS Summary Report F8480018
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area:
F848 Retention Basin Concrete Storage Survey Unit:
0018 Open Land Area Class:
2 LTP Table 5-4 SU Area (m2):
1059 Evaluator:
Gary Frank DCGL for Cs-137 surrogate (pCi/g):
52.6 DCGL for Co-60 (pCi/g):
12.6 Area Factor:
N/A Class 2 Design DCGLemc (pCi/g):
N/A Class 2 LBGR (pCi/g):
25.6 Adjusted Design Sigma (pCi/g):
0.49 DTBD-06-001, Table 5-4A or B Type I Error:
0.05 Type II Error:
0.05 Sample Area (m2):
117.7 Class 2 Total Area Scanned (m2):
283 Scan Coverage (%):
26.7%
Class 2 ZJ-* :
1.645 ZI-0 :1.645 Sign P:
0.99865 Calculated Relative Shift:
55.1 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:
10.8 Class 2 Page 3 of 8 FSS Summary Report P8480018.
Survey Results:
A total of 16 direct measurements were made in F8480018. The results are shown in Table 2-1. Statistical data including the mean, median, and standard deviation are shown in Table 2-2. All of the direct measurements were less than Unity. None of the scan measurements indicated areas of elevated activity. Soil samples were counted to the MDCs shown in Table 2-1 of Attachment 2.
Page 4 of 8 FSS Summary Report F8480018
Table 2-1. Direct Measurement Results (all activity values in pCi/g)
Cs137
______Co6O Unity Unity Unity Sample ID MDA Activity Uncertainty Value MDA Activity Uncertainty Value Total F8480018S0001SS 6.16E-02 6.51E-01 7.82E-02 0.0124 7.49E-02
<7.49E-02 0.0059 0.0183 F8480018S0002SS 6.04E-02 7.31E-01 8.18E-02 0.0139 7.37E-02
<7.37E-02 0.0058 0.0198 F8480018S0003SS 8.72E-02
<8.72E-02 0.0017 7.59E-02
<7.59E-02 0.006 0.0077 F8480018S0004SS 5.97E-02 1.36E-01 4.73E-02 0.0026 6.77E-02
<6.77E-02 0.0054 0.008 F8480018S0005SS 5.95E-02 1.18E00 1.01E-01 0.0224 3.44E-02 1.67E-01 3.59E-02 0.0132 0.0356 F8480018S0006SS 6.57E-02
<6.57E-02 0.0012 4.78E-02
<4.78E-02 0.0038 0.005 F8480018S0007SS 6.86E-02
<6.86E-02 0.0013 4.1OE-02
<4.1OE-02 0.0033 0.0046 F8480018S0008SS 5.04E-02 5.68E-02 3.45E-02 0.0011 5.OOE-02
<5.OOE-02 0.004 0.005 F8480018S0009SS 5.82E-02 6.88E-01 7.90E-02 0.0131 9.21E-02
<9.21E-02 0.0073 0.0204 F8480018S0010SS 5.84E-02
<5.84E-02 0.0011 5.27E-02
<5.27E-02 0.0042 0.0053 F8480018S0011SS 5.31E-02
<5.31E-02 0.001 5.21E-02
<5.21E-02 0.0041 0.0051 F8480018S0012SS 6.83E-02 2.08E-01 5.57E-02 0.004 6.58E-02 5.09E-01 6.OOE-02 0.0404 0.0444 F8480018S0013SS 4.41E-02 2.94E-01 5.33E-02 0.0056 5.14E-02
<5.14E-02 0.0041 0.0097 F8480018S0014SS 4.55E-02 1.27E-01 4.03E-02 0.0024 6.18E-02
<6.18E-02 0.0049 0.0073 F8480018S0015SS 7.85E-02
<7.85E-02 0.0015 5.69E-02
<5.69E-02 0.0045 0.006 F8480018S0016SS 6.19E-02
<6.19E-02 0.0012 5.18E-02
<5.18E-02 0.0041 0.0053 Page 5 of 8 FSS Summary Report F8480018
Table 2-2. Direct Measurements Results Summary Cs 137 CoGO
~
Activity Activity Cs137 Unity Co60 Unity Unity Total (PCi/gj)
(pCi/q)
DCGLw 52.6 12.6 Mean 2.84E-01 9.54E-02 0.0054 0.0076 0.013 Median 1.07E-01 5.94E-02 0.002 0.0047 0.0075 Standard Dvation 3.39E-01 1.14E-01 0.0065 0.0091 0.012 Deviation Cs137 Activity Range (pCi/g) 5.31E-02 to 1.18E00 Co60 Activity Range (pCi/g) 4.1OE-02 to 5.09E-01 Cs137 Unity Range 0.001 to 0.0224 Co60 Unity Range 0.0033 to 0.0404 Total Unity Range 0.0046 to 0.0444 Sample Count 16 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 less than the design standard deviation so no additional samples were required.
Page 6 of 8 FSS Summary Report F8480018
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N):
16 Median (unity):
0.008
. Mean (Unity):
0.013 Direct Measurement Std Deviation (Unity):
0.012 Maximum (Unity):
0.044 Sign Test Final N Value:
16 S+ Value:
16 Critical Value:
11 Sufficient Samples Collected:
Yes Maximum Value < Unitized DCGL:
Yes Median Value < Unitized DCGL:
Yes Mean Value < Unitized DCGL:
Yes Maximum Value < DCGLemc (Unity):
N/A Class 2 Standard Deviation <= Sigma:
Investigate <0.5 DCGL for both Cs-137 and Co-60 Pass the Sign Test?
Yes Reject the Null Hypothesis?
Yes Does the Survey Unit Pass All Criteria?
Investigate Survey Passes Page 7 of 8 FSS Summary Report F8480018
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 2 land suryey and the sample results are consistent with that classification. The variability of the survey results was less thanthe 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 2 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 Unity. 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 F8480018 meets the release criteria of 10CFR20.1402.
Page 8 of 8 FSS Summary Report F8480018 Maps March 25, 2008 Survey Unit F8480018
0 0
-Pl.
00 00 6812976E 1888201N 6812892E 1888143N 681 28P05E 188808ON--
6813014E 18880173N 6813008E 1888082N SMUD RETENTION BASIN CONCRETE STORAGE SOIL SAMPLE/GAMMA DIRECT F8480018 - Ml
0~4ý-
6812938E 01GS 1888081N 6812967E 02GS 1888087N 03GS 6812997E 1888100N 04GS 6812861E 1888111N 6812958E 05GS 1888117N 06GS 6812990E 1888131N 6812920E 07GS 1888146N OBGS 6812958E 1888153N 09GS 6812994E 1888159N 1OGS 6812971E 1888182N 6812976E 1888201 N i K 6813014E 18880173N 1888082N Ir1 00 00 00 SMUD RETENTION BASIN CONCRETE STORAGE ISOCS GAMMA SCANS F8480018 - M2
0 6812976E 1888201N 6813014E
,18880173N I'1 00 00 00 SMUD RETENTION BASIN CONCRETE STORAGE 44-10/SPA.-3 SCANS F8480018 - M3 Instrumentation March 25, 2008 Survey Unit F8480018
Table 2-1. Survey Unit Instrumentation Detector Detector Serial Instrument Model MDC No.
No.
HPGe N/A 05069128 Soil-1.18 pCi/g Cs-137 Soil - 0.509 pCi/g Co-60 SN/A 2983947 Soil - 0.42 pCi/g Cs-137 Soil - 0.26 pCi/g Co-60 Nal 44-10 171992 Soil - 5.2 pCi/g Cs-137 Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value ISOCS Investigation Criteria - Scan Soil - 26.3 pCi/g Cs-137 Soil - 6.3 pCi/g Co-60 NaI Investigative Criteria -8212 cpm Scan All DCGLw 52.6 Cs-137 12.6 Co-60 All DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8480018 Investigation March 25, 2008 Survey Unit F8480018 (none required)
Data Assessment March 25, 2008 Survey Unit F8480018
-D rt~
0 CD CD 00 00 F8480018 Quantile Plot I--
N 0.050 -
0.045 -
0.040 -
0.035 -
0.030 -
0.025 -
0.020 -
0.015 0.010 -
0.005 -
0.000 -
I 0.008 0
20 40 60 80 100 Percentile Unitized Total Value -
Median -
- - 75th Percentile --
- 50th Percentile]
CD 0o 0
4-1 00 00 00 F8480018 Scatter Plot 0
N 0.060 0.050 0.040 0.030 0.020 0.010 0.000
-0.010
-0.020
-0.030 0
0 o
0 0
0 0
0 0
0 0
0 0
ýO 0
0 0.049 0.013
-0.023 I
I I
I I
Measurement Locations 0
Unitized Total Value -
-Average
"+3StDev"--
"-3StDev"
CD c'*
0
-P, 00 00 00 00 F8480018 Frequency Plot 0
a) a)
U-0 (1) 0 11 10 9
8 7
6 5
4 3
2 1
0 Bins - Upper End Value (Unitized Total)