ML081610152
| ML081610152 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/17/2008 |
| From: | Donna Anderson Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| F5010041 | |
| Download: ML081610152 (21) | |
Text
Rancho Seco Final Status Survey Summary Report March 17, 2008 Extended Parking/Storage Area Survey Unit F5010041 Prepared By: ________
Date: _
_//7_
FSS Exieer Reviewed By:___
Date:
7/,0 LeaoV FSS Engineer Approved By:
Date:_
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F5010041, Extended Parking/Storage Area Survey Unit
Description:
Operating History: The area extended from the parking lot to the plant access road in the northeast quadrant of the site. Operating records and the HSA document the potential for a release of radioactivity in this survey area. The HSA recorded two potential release events. One event involved the discovery of a pallet of articles labeled as "Contact RP prior to disassembly outside the RCA". In addition, the area wasused as a staging area for outgoing and incoming radioactive material shipments. The access road over which shipments were made runs through the area.
Site Characterization: Soil 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 0.088 pCi/g and a maximum value of 0.232 pCi/g. Based on the classification procedure (DSIP-0020), the area was determined to be a Class 3 area.
HSA Events: none 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 3,080 m2 were scanned for approximately 7%
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 7 FSS Summary Report F5010041
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area:
F50I Extended Parking/Storage Area Survey Unit:
0041 Open Land Area Class:
3 LTP Table 5-4 SU Area (m2):
42,735 F8000071 Evaluator:
D. Anderson DCGL Cs137 surrogate (pCi/g):
51.2 Area Factor:
N/A Class 3 Design DCGLemc (pCi/g):
N/A Class 3 LBGR (pCi/g):
.51.0 Adjusted Design Sigma (pCi/g):
0.058 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):
3,080 Scan Coverage (%):
7.2%
Class 3 Zl-, :,1.645 ZI-p:
1.645 Sign P:
0.99865 Calculated Relative Shift:
3.4 Relative Shift Used:
.3 Uses 3.0 if Rel Shift >3 N-Value:
11 Design N-Value + 20%/o:
14 NUREG-1575 Table 5-5 Grid Spacing L:
N/A Class 3,
IPage 3 of 7 FSS Summary Report F5010041
Survey Results:
A total of 14 direct measurements were made in F5010041. 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:
9.30E-02 Median:
8.36E-02 Standard Deviation:
5.42E-02 Range:
3.78E-02 to 2.51E-01 F5010041S0001SS 7.48E-02
< 7.48E-02 F5010041S0002SS 9.87E-02
< 9.87E-02 F5010041S0003SS 1.11E-01
< 1.11E-01 F5010041S0004SS 1.08E-01
< 1.08E-01 F5010041S0005SS 7.66E-02
< 7.66E-02 F5010041S0006SS 6.28E-02
< 6.28E-02 F5010041S0007SS 5.39E-02 2.51E-01 6.43E-02 F5010041S0008SS 7.53E-02 1.41E-01 5.68E-02 F5010041 S0009SS 4.54E-02 1.00E-01 3.82E-02 F5010041S0010SS 6.55E-02 9.05E-02 4.73E-02 F5010041S0011SS 5.20E-02
< 5.20E-02 F5010041S0012SS 5.33E-02
< 5.33E-02 F5010041S0013SS 4.40E-02
< 4.40E-02 F5010041S0014SS 3.78E-02
< 3.78E-02 Page 4 of 7 FSS Summary Report F5010041
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 Report1 F5010041
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N):
14 Median (pCi/g):
8.36E-02 Mean, (pCi/g):
9.30E-02 Standard Deviation (pCi/g):
5.42E-02 Maximum (pCi/g):
2.51E-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 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 F5010041
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 ýs 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 F5010041 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F5010041 Maps March 17, 2008 Survey Unit F5010041
t~j 222767E2253428E 2252767E249598N 0249598N i
~I~Lg 225278E
-225.3000E 248816N 2252598E 1I 248817N 2253428E 248398N PORTL I A~~q3
,/AREHOUSEf 2252598E--___
248498N 289N 2252927E Map F5010041 -1, Extended Parking/Storage Area (Lands) 24898 IA52927E Area Estimate: 42 735 so. meters
I "S'002S --------
SS ~ a s99 SoOOl 2S Ss ss49 SOOC SSS 9398 500O6SS
__________9298 Sooliss 9098
~ lassS0014SS
________8998 Bldg
_________.8798 1A Dess
-(
P 18____
398 N
Map F5010041-2, Extended Parking/Storage Area (Lands)
Class 3 Soil Sample Locations F5010041S0001SS to F5010041S0014SS Page 3 of 7 Att. 1 Maps F5010041
Na Map F5010041-3, Extended Parking/Storage Area (Lands)
Class 3 Soil Sample Locations with Coordinates F5010041SOOO1SS to F5010041S0014SS Page 4 of 7 Att. 1 Maps F5010041
0-1
>t)
Barbed Wire Fencing Paved Parking C
U-C-)
ci N
Hazmat Bldg Map F5010041-4, Extended Parking/Storage Area (Lands)
ISOCS Gamma Scan Measurements north of Hazmat Building F5010041SO001GS to F5010041SO040GS 28 sq. meter field of view Total Scan Area: 1,120 sq. meters
N Fence Sa a a*4$U4G Seoaw S SO OT1CSSon SOUM oo~
SO O
hIS sra S~O83G UDOQC~
SOOI~
SO~I ~
'S~lis SO S H53G. SCOIS
-II I
aS 0
Map F5010 04 1 5, Extended P r i gso~ ~ A e L n s
)SOCS Gamma Scan Me asremeng/ts rg raLns OlQ041O)4lso1GS to F5010041SOo90GS 28 Sq. Meter field of view Total Scan Area: 1-680sq. meters Page of7Att.
I Maps F501004 1
Fence Fence iHazmat Bldg I
ii
'8 i
i I
IC.0 L...
Paved Parking Grassy Slope N
Access Road Map F5010041-6, Extended Parking/Storage Area (Lands)
ISOCS Gamma Scan Measurements F5010041S0091GS to F5010041SO100GS 28 sq. meter field of view Total Scan Area: 280 sq. meters Page 7 of 7 Att. 1 Maps F5010041 Instrumentation March 17, 2008 Survey Unit F5010041
Table 2-1. Survey Unit Instrumentation Detector Detector Serial Instrument Model No.
MDC NNo.
Soil - 6.56e-2 pCi/g Cs-137 Soil - 5.79e-2 pCi/g Soil - 2.18e-1 pCi/g Cs-137 Soil - 1.29e-1 pCi/g Co-60 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 All DCGLw 51.2 Cs-137 12.6 Co-60 All DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8480017 Investigation March 17, 2008 Survey Unit F5010041 (none required)
Data Assessment March 17, 2008 Survey Unit F5010041
F5010041 Quantile Plot Cs137 DCGL =51.2 pCVg LnJ 0
t-o 0
0.300 0.250 0.200 0
C-
>, 0.150 low 0.100 0.050 0.000 0.084 0
20 40 60 80 100 Percentile Activity -
Median --
- 75th Percentile....
50th Percentile
0 CD2
ý3 I'T 0/
03 0"
F5010041 Scatter Plot Cs137 DCGL = 61.2 pClIg 3.00E-01 2.60E-01 2.SOE-01 1.50E-01 1.-00E-01 5.OOE 02-0.00E+OO
-6.00E-02
-1 OP-M.I 0
0 0
0 0
00 0
I I
14* WW N
4-A, 96O 4
4 Measurement Locations 0.093 4009
=0 Activity -
Average
"+3StDev" -
"-3StDev ",I
0 0
0 0
CD CD In F5010041 Frequency Plot Cs1 37 DCGL = 51.2 pCi/g 8-0 C0 0-C) 0 (U
(0
©0 7
6 5
4 3
2 1
0-N N
0 cv I'\\ -
t\\.-
Bins - Upper End Value (pCi/g)