ML081610118
| ML081610118 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/29/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| F5010032 | |
| Download: ML081610118 (19) | |
Text
Rancho Seco Final Status Survey Summary Report November 5, 2007 Hazardous Materials Warehouse Pad Survey Unit F5010032 Prepared By:
Date: 7-4-14',*e Reviewed Date:
- 7-_
Date: __ 7
_-O Dismantlement Superintendent, Radiological.
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F5010032, Hazardous Materials Warehouse Pad Survey Unit
Description:
Operating History: The structure which existed on the pad prior to demolition was used for the staging, shipment and receipt of material, including radioactive material. The HSA documented the presence of radioactive material prepared for shipment within the area.
Site Characterization: Direct measurements were made which confirmed the presenceof plant-derived radionuclides. Cs-137 was the primary nuclide of plant origin detected with a mean gross activity level of 1,913 dpm/100 cm2 and a maximum value of 2,642 dpmr/100 cm. Based on the classification procedure (DSIP-0020) and levels of gross activity reported, 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 49.5 m2 were scanned.for approximately 18%
coverage. Samples of removable contamination were collected at each direct measurement locatiori. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.
Operating History:
Page 2 of 8 FSS Summary Report F5010032
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:
F501 Hazardous Materials Warehouse Pad Structure Surface LTP Table 5-4 Survey Unit:
Class:
SU Area (m2):
Evaluator:
DCGL (dpm/100 cm2):
Area Factor:
Design DCGLemc (dpm/100 cm 2):
LBGR (dpm/100 cm 2):
Design Sigma (dpm/100 cm 2):
Type I Error:
Type II Error:
Predominant Nuclide:
Sample Area (M2):
Scan Area (M2):
Scan Coverage (%):
ZlIa :
ZI-P :
Sign P:
Calculated Relative Shift:
Relative Shift Used:
N-Value:
Design N-Value + 20%:
Design Min Samples N:
Grid Spacing L:
0032 3
268 DA Tallman 43000 N/A N/A 21500 397 0.05 0.05 Cs-137 N/A 49.5 18%
1.645 1.645 0.99865 54.1 3
11 14 14 N/A 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 3 of 8 FSS Summary Report F5010032.
Survey Results:
A total of 14 direct measurements were made in F5010032. 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. Scan activity ranged from 4577 to 5655 dpm/100 cm2, based on a surveyor efficiency of 0.5 and no background subtracted. 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 Activit (dpm/100 cm F5010032-COOOI BD 2339 F5010032-CO002BD 2469 F5010032-CO003BD 2552 F5010032-CO004BD 2469 F5010032-CO005BD 2547 F5010032-CO006BD 2594 F5010032-CO007BD 2614 F5010032-CO008BD 2537 F5010032-CO009BD 2334 F5010032-COOIOBD 2583 F5010032-COOIIBD
-2666 F5010032-CO012BD 2381 F5010032-CO013BD 2521 F5010032-CO014BD 2438 Mean:
2503 Median:
2529 Standard Deviation:
102 Range:
2334-2666 Page 4 of 8 FSS Summary Report F5010032
Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2)
+
F5010032C0001SM F5010032C0002SM F5010032C0003SM F5010032C0004SM F5010032C0005SM F5010032C0006SM F5010032C0007SM F5010032C0008SM F5010032C0009SM F5010032C0010SM F5010032C0011SM F5010032C0012SM F5010032C0013SM F5010032C0014SM Mean:
Median:
Standard Deviation:
Ranqe:
-2.24
-0.95
-4.82
-4.82
-0.95
-3.53
-4.82
-4.82
-2.24
-2.24 0.34
-4.82
-4.82
-3.53
-3.16
-3.53 1.79
-4.82 to 0.34 Page 5 of 8 FSS Summary Report F5010032
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 less than the design standard deviation so no additional samples were required.
Page 6 of 8 FSS Summary Report F5010032
Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm2):
N/A Ambient Background Used (dpm/100 cm2):
N/A Average Ambient BKG 0
Actual Direct Measurements (N):
14 Median (dpm/100 cm2):
2529 Mean (dpm/100 cm2):
2503 Direct Measurement Standard Deviation 102 (dpm/100 cm 2):
Total Standard Deviation (dpm/100 cm2):
102 Based on samples and backgrounds.
Maximum (dpm/100 cm2):
2666 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:
Yes Pass the Sign Test?
Yes Reject the Null Hypothesis?
Yes Does the Survey Unit Pass All Criteria?
Yes Page 7 of 8 FSS Summary Report F5010032
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 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. No direct measurements exceeded the DCGL of 43000 dpm/100 cm 2 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 F5010032 meets the release criteria of 1 OCFR20.1402.
Page 8 of 8 FSS Summary Report F5010032 Maps November 5, 2007 Survey Unit F5010032
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RC RAYMOND niF~ 501002 SC RAYMOND Instrumentation, November 5, 2007 Survey Unit F5010032
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No.
Model; Serial No.
(dpm/100 cm 2)
(dpm/100 cm 2)
M2350; 189089 43-68B; 148460 433 1033 M2350; 142499 43-37; 148502 198 616 Tennelec; 0401171 N/A 5 dpm a, 11 dpmf3 N/A Table 2-2. Investigation Criteria and DCGL Parameter Value (dpm/100 cm2)
Investigation Criteria - Direct 21500 Investigation Criteria-Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F5010032 Investigation November 5, 2007 Survey Unit F5010032 (none required)
Data Assessment November 5, 2007 Survey Unit F5010032
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C F501 0032 Gross Activity Sample Results Quantile Plot DCGL = 43000 dprn/100cm=2 T-2,700 2,650 2,600 2,550 2,500 2,450.
2,400 2,350 2,3_00 2529 0
20 40 60 80 100
/ 71 Percentile
+
DirectMeasurements (dpm/100cm2) nmedian --
75th Percentile...
50th Percentile
LjJ F5010032 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpml1 00cm2 3000 S2810
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