ML090850554
| ML090850554 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/16/2008 |
| From: | Ellen Brown Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097 | |
| Download: ML090850554 (20) | |
Text
Rancho Seco Final Status Survey Summary Report December 16, 2008 North Laydown Area Adjacent toTurbine Building Survey Unit F8260251 Prepared By:&2_x L.
FSS Engineer Date: 1Z2/L*, 1o20 Reviewed By:
Date: k Lead FSS Engineer Approved By:
Date:
- - ; 7 -?
.Dismantlement Sijperintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F826025 1, North Laydown Area Adjacent toTurbine Building Survey Unit
Description:
Operating History: The area consisted of the foundation pad for the main transformer and was adjacent to the rail spur serving the Turbine and Fuel Buildings. As such, the area was used for loading and transport of radioactive material for shipment off site. There were no specific operational surveys documenting contamination in this area.
Site Characterization: Based on the classification procedure (DSIP-0020) and the characterization survey data, the area was determined to be a Class 3 area.
Page 2 of 9 FSS Summary Report F8260251
Survey Area Classification 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 169 m2 were scanned for approximately 25%
coverage. Samples of removable contamination were collected at each direct measurement location. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.
Page 3 of 9 FSS Summary Report F8260251
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:
Survey Unit:
Class:
SU Area (m2):
Evaluator:
DCGL (dpm/100 cm2):
Area Factor:
Design DCGLemc (dpm/100 cm 2):
LBGR (dpm/100 cm2):
Design Sigma (dpm/100 cm2):
Type I Error:
Type II Error:
Predominant Nuclide:
Sample Area (m2):
Scan Area (M2):
Scan Coverage (%):
Zl-, :
Sign P:
Calculated Relative Shift:
Relative Shift Used:
N-Value:
Design N-Value + 20%:
Design Min Samples N:
Grid Spacing L:
F826 0251 3
679 Erin L. Brown 43000 N/A N/A 21500 46 0.05 0.05 Cs-137 N/A 169 25%
1.645 1.645 0.99865 467.3 3
11 14 14 N/A North Laydown Area Adjacent toTurbine Building Structure Surface LTP Table 5-4 Gross Activity DCGL Class 3 Class 3 Default = 50% DCGL Class 3 Class 3 Uses 3.0 if Relative Shift is
>3 NUREG-1575 Table 5-5 Class 3 Class 3 Page 4 of 9 FSS Summary Report F8260251
Survey Results:
A total of 14 direct measurements were made in F826025 1. The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. None of the scan measurements indicated areas of elevated activity. Co-60 and Cs-137 were not identified above the MDA. Samples for removable surface activity were all less than 10% of the DCGL as shown in Table 3. Removable surface activity samples were counted for alpha activity and none was detected at the MDC shown in Table 2-1 of Attachment 2.
Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/100 cm F8260251-CO001BD 2054 F8260251-CO002BD 1930 F8260251-CO003BD 1893 F8260251 -CO004BD 1893 F8260251-CO005BD 3247 F8260251-CO006BD 2059 F8260251-CO007BD 2179 F8260251-CO008BD 2044 F8260251-CO009BD 2090 F8260251-Co01OBD 1966 F8260251 -COOI 11BD 2464 F8260251-CO012BD 2148 F8260251-CO013BD 2018 F8260251-CO014BD 2127 Mean:
2151 Median:
2057 Standard Deviation:
347 Range:
1893-3247 Page 5 of 9 FSS Summary Report F8260251
Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2)
F8260251COOOISM F8260251CO002SM F8260251 C0003SM F8260251 C0004SM F8260251CO005SM F8260251CO006SM F8260251 C0007SM F8260251 C0008SM F8260251 C0009SM F8260251Co010SM F8260251CO011SM F8260251CO012SM F8260251CO013SM F8260251CO014SM Mean:
,Median:
Standard Deviation:
Range:
6.16 1
4.87
-0.29 1
-1.58
-2.88
-0.29
-0.29 2.29
-0.29
-1.58 1
2.29 0.81 0.35 2.47
-2.88 to 6.16 Page 6 of 9 FSS Summary Report F8260251
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 4. 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 resulted in a relative shift greater than three so no additional samples were required.
Page 7 of 9 FSS Summary Report F8260251
Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm'):
N/A Ambient Background Used (dpm/100 cm2):
N/A Average Ambient BKG = 0 Actual Direct Measurements (N):
14 Median (dpm/100 cm2):
2057 Mean (dpm/100 cm2):
2151 Direct Measurement Standard Deviation 347 (dpm/100 cm 2):
Total Standard Deviation (dpm/100 cm 2):
347 Based on samples and backgrounds.
Maximum (dpm/100 cm 2);
3247 Material Type:
N/A Background Subtract Not Applied 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 Total Standard Deviation <= Sigma:
No No Additional Samples required Pass the Sign Test?
Yes Reject the Null Hypothesis?
Yes Does the Survey Unit Pass All Criteria?
Yes Page 8 of 9 FSS Summary Report F8260251
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 structure 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. No direct measurements exceeded the DCGL of 43000 dpm/100 cm2 and none of the removable surface activity measurements exceeded 10% of 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 F8260251 meets the release criteria of 10CFR20.1402.
Page 9 of 9 FSS Summary Report F8260251
.Attachment 1 Maps December 16, 2008 Survey Unit F8260251
(D 4a E6813a35 N1888747 7306 sq: ft 678.75 sq; m.
I 0
E6813759 Ni 8887;47
- .:~3
- SQ:.
STEEL PWL 00 I'.
- sm0 SACRAMENTO MUNICIPAL LfflLIrY DISTRICT NORTH LAYDOWN AREA GENERAL ARRANGEMENT SURFACE AREA ESTIMATE F8260251 - M 1 j __________________________
0 00
- smuo SACRAMENTO MUNICIPAL UTILITY DISTRICT NORTH LAYDOWN AREA DIRECT MEASUREMENT LOCATION F8260251 -M2
4Cb 0r U)2 r---
0 I',J 00
- smuo SACRAMENTO MUNICIPAL UTlLITY DISTRICT NORTH LAYDOWN AREA SCAN MEASUREMENT LOCATION F8260251 -M3 Instrumentation December 16, 2008 Survey Unit F8260251
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No.
Model; Serial No.
(dpm/100 cm,:)
(dpm/100 cm 2 )
M2350; 193700 43-68B; 190294 433 1033 Tennelec; 0401171 N/A 5 dpm a, 11 dpm 3 N/A Co 780 ISOCS 1983920 N/A Co-607-1780 Cs-137 - 1180 Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm 2)
Investigation Criteria - Direct 21500 Investigation Criteria-Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8260251 Investigation December 16, 2008 Survey Unit F8260251 (none required)
Data Assessment December 16, 2008 Survey Unit F8260251
CD 0
CD CD 00 F8260251 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1 00cm2 I
4-3,5.00 3,000 2,500 2,000 1,500 1,000 500 U
2057 0
20 40 60 80 100 Percentile Direct Measurements (dpr/lO0cm2)
-median
- - 75th Percentile.
50th Percentile
CD 0
A F8260251 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmlO00cm2 A
Ca 00 ON 0O 3500
.3000-E
'u 2500-C 2000-150oo a1000-500 0,
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0 Measurement Locations 3193 2151 11109 I o Gross Activity -
Average a
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a
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F8260251 Gross Activity Frequency Plot DCGL = 43000 dpm/1 00cm2 6)
LL 0
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Bins - Upper End Value (dpm/1 00cm2)