ML081580572
| ML081580572 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/01/2008 |
| From: | Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-032 | |
| Download: ML081580572 (18) | |
Text
Rancho Seco Final Status Survey Summary Report April 1, 2008 Diesel Tank Storage Pad Survey Unit F8320001 Prepared By: i/;,
. -. *m9 Date: 4
' Z2CcB FS gi eer Reviewed By:
Date:
Lead FSS Engineer Approved By:
Date:
Dismantlement SIeperintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8320001, Diesel Tank Storage Pad Survey Unit
Description:
Operating History: This land area contained the diesel tank which was used to fuel the diesel generators on site.
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 141 m2 were scanned for approximately 9%
coverage. Soil samples were collected at 14 randomly determined locations 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 F8320001
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area:
F832 Diesel Tank Storage Pad Survey Unit:
0001 Open Land Area Class:
3 LTP Table 5-4 SU Area(m2):
1560 Evaluator:
Erin L. Brown DCGL Cs137 surrogate (pCi/g):
51.2 Area Factor:
N/A Class 3 Design DCGLemc (pCi/g):
N/A Class 3 LBGR (pCi/g):
25.6 Adjusted Design Sigma (pCi/g):
0.01 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):
141 Scan Coverage (%):
9%
Class 3 ZJ-,, :
1.645 ZI-p :
1.645 Sign P:
0.99865 Calculated Relative Shift:
2560 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 F8320001
Survey Results:
A total of 14 direct measurements were made in F8320001. 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:~
5.05E-02 Median:
4.91E-02 Standard Deviation:,
6.17E-03 Range:
4.34E-02 to 6.26E-02 F8320001SOOO1SS 4.84E-02
< 4.84E-02 F8320001S0002SS 4.97E-02
< 4.97E-02 F8320001S0003SS 4.70E-02
< 4.70E-02 F8320001S0004SS 4.34E-02
< 4.34E-02 F8320001S0005SS 5.48E-02
< 5.48E-02 F8320001S0006SS 4.37E-02
< 4.37E-02 F8320001S0007SS 4.45E-02
< 4.45E-02 F8320001S0008SS 5.91E-02
< 5.91E-02 F8320001S0009SS 4.99E-02
< 4.99E-02 F8320001S0010SS 5.36E-02
< 5.36E-02 F8320001S0011SS 5.77E-02
< 5.77E-02 F8320001S0012SS 4.47E-02
< 4.47E-02 F8320001SO013SS 4.72E-02
< 4.72E-02 F8320001S0014SS 6.26E-02
< 6.26E-02 Page 4 of 7 FSS Summary Report F8320001
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 F8320001
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N):
14 Median (pCi/g):
4.9 1E-02 Mean (pCi/g):
5.05E-02 Standard Deviation (pCi/g):
6.17E-03 Maximum (pCi/g):
6.26E-02 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 Class 3 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 F8320001
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 less 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 F8320001 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F8320001
-Attachment 1' Maps April 1, 2008 Survey Unit F8320001
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ADIESEL STORAGE PAD 4.SMUDSAMPLE LOATIONS UTI~LTY DIS'TRICT FlLE: 832000 RC PAYII4OND
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C0 D4ESEL STORAGE
-.KEff LA 881.3,74E 18889M N 8013674E 188U915N
, SQ 14 SOL oTJ 00 0C) sMUD SACRAI*ENTO MUNICIPAL UTILTfY DISTRICT 0 1 2:
4 5 SSCALE
- METERS, DIESEL STORAGE PAD GENERAL ARRANGEMENT SURFACE AREA ESTIMATE F8320001 -M3 832000 Instrumentation April 1, 2008 Survey Unit F8320001
Table 2-1. Survey Unit Instrumentation Detector Detector Serial Instrument Model oMDC No.No.
HPGe N/A 05069128 Soil - 6.27E-08 pCi/g Cs-137 ISOCS N/A 2983947 Soil - 2.72E-01 pCi/g Cs-137 Soil - 2.83E-01 pCi/g Co-60 Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value ISOCS Investigation Criteria - Scan Soil - 20 pCi/g Cs-137.
51.2 Cs-137 All DCGLw 12.6 Co-60 All DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8320001 Investigation April 1, 2008 Survey Unit F8320001 (none required)
Data Assessment April 1, 2008 Survey Unit F8320001
(D 0
4_11 F8320001 Quantile Plot Cs137 DCGL = 51.2 pCi/g 0.080 0.070 0.060 B 0.050
--,0.040 3;
- ~0.030 0.020.
0.010 0.000 0.049 0
20 40 60 80
.100 Percentile Activity -
Median -
75th Percentile..-.
50th Percentile 00 C!
C)
CD w
En uJ 0
C'D 00 t'j)
C)
C)tD, F8320001 Scatter Plot Cs137 DCGL = 51.2 pClIg 8.OOE-02 7.0 0 E,.0 2 -
.. 0 6 6.OOE-02 069 000 R
S..OOE-02 0
-00 00 0
0 0
0 4,OOE-02
- > 3*OOE ----
3.032 2.00E-02 1.OOE-02 O.OOE+00 I
I Measurement Locations 0
Activity -
Average -
"+3StDev....-
3StDevI
CD ITI 00 C~)
C0 0
F8320001 Frequency Plot Cs137 DCGL = 51.2 pCi/g a.)
Cr 2i)
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.0 a,)
~0 6
5 4
3 2
1 0
~x.
AI/I AT
,tK -
C Bins - Upper End Value (pCi/g)