ML082620108
| ML082620108 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/28/2008 |
| From: | Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-064 | |
| Download: ML082620108 (31) | |
Text
Rancho Seco Final Status Survey Summary Report February 28, 2008 POL Building Survey Unit F8540001 Prepared By: Date:_______
Reviewed By: Date:___________
'Lead F Engineer Approved By: Date: 7 ?
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8540001, POL Building Survey Unit
Description:
Operating History: The POL Building is used for the storage of petroleum, oil and lubricants for Warehouse A. This structure was used as a primary site warehouse with attached office space. This area was not reported to have been used for the storage of radioactive material. Operating records and the HSA document no occurrences of radioactive material with the potential for a release of radioactivity associated with this survey area.
Site Characterization: Direct measurements were made of the interior and exterior surfaces of the structure which confirmed the absence of plant-derived radionuclides. 2 Direct measurements interior showed a mean gross activity level of 1,941 dpm/100 cm and a maximum value of 3,397 dpm/100 cm 2 . Direct measurements exterior showed a mean gross activity level of 2,310 dpm/100 cm 2 and a maximum value of 3,838 dpm/100 cm 2 . 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 37 m 2 were scanned for approximately. 14%
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 2 of 8 FSS Summary Report F8540001
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F854 POL Building Survey Unit: 0001 Structure Surface Class: 3 . LTP Table 5-4 SU Area (m2): -260 Evaluator: Gary Frank DCGL (dpm/IOO.cm 2): 43000 Gross Activity DCGL Area Factor: N/A Class 3 Design DCGLemc N/A Class 3 2
(dpr 100 cm ),
LBGR (dpm/100 cm2): 21500 Default = 50% DCGL Design Sigma (dpm/100 cm 2): 495 Type I Error: 0.05 Type II Error- 0.05 Predominant Nuclide: Cs-137 Sample Area (m2 ): N/A Class 3 Scan Area (m2): 37 Scan Coverage (%): 14% Class 3 1.645 1.645 Sign P: 0.99865 Calculated Relative Shift: 43.4 Relative Shift Used: 3 Uses 3.0 if Relative Shift is
>3 N-Value: 11 Design N-Value + 20%: 14 NUREG-1575 Table 5-5 Design Min Samples N: 14 Class 3 Grid Spacing L: N/A Class 3 Page 3 of 8 FSS Summary Report F8540001
Survey Results:
A total of 14 direct measurements were made in F8540001. 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 1601 to 8994 dpm/l 00 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 Activity (dpm/100 cm)
F8540001-MOOOIBD 711 F8540001-MOO02BD 631 F8540001 -CO003BD 1899 F8540001-MOO04BD 714 F8540001-MOO05BD 741 F8540001-MOO06BD 692 F8540001 -MOO07BD 754 F8540001-MOO08BD 708 F8540001-MOO09BD 594 F8540001-MOOIOBD 674 F8540001-MO011BD 609 F8540001-MOO12BD .649 F8540001-MOO13BD 717 F8540001-MOO14BD 898 Mean: 785 Median: 709 Standard Deviation: 329
. Range: 594-1899 Page 4 of 8 FSS Summary Report F8540001
Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/1O0 cm 2 )
F8540001 MOOOI SM 1.64 F8540001 M0002SM -2.24 F8540001M0003SM -0.95 F8540001 M0004SM -2.24 F8540001MOOO5SM -0.95 F8540001 M0006SM -3.53 F8540001M0007SM -2.24 F8540001MOO08SM -2.24 F8540001 M0009SM -0.95 F8540001MOO10SM -0.95 F8540001 M0011 SM -2.24 F8540001MOO12SM -4.82 F8540001MOO13SM -2.24 F8540001 M0014SM -0.95 Mean: -1.78 Median: -2.24 Standard Deviation: 1.49 Range: -4.82 to 1.64 Page 5 of 8 FSS Summary Report F8540001
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, no additional samples were required.
Page 6 of 8 FSS Summary Report F8540001
Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2 ): N/A Ambient Background Used (dpm/100 cm 2): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 14 Median (dpm/100 cm 2): 709 Mean (dpm/100 cm ):2 785 Direct Measurement Standard Deviation 329 (dpm/1O0 cm 2):
Total Standard Deviation (dpm/100 cm 2): 329 Based on samples and backgrounds.
Maximum (dpm/100 cm 2 ): 1899 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 F8540001
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 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 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 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 F8540001 meets the release criteria of 10CFR20.1402.
Page 8 of 8 FSS Summary Report F8540001
Attachment 1 Maps February 28, 2008 Survey Unit F8540001
Petroleum Oil Lubricant Building (POL) 0 Interior Exterior
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Attachment.2 Instrumentation February 28, 2008 Survey Unit F8540001
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cm2 ) (dpm/100 cm')
M2350; 193700 43-68B; 190294 433 1033 M2350; 193700 43-68B; 160691 433 1033 Tennelec; 0401171 N/A 5.9 dpm a N/A 11.7 dpm /3 Table 2-2. Investigation Criteria and DCGL Value Param eter (dpm/100 cm 2 )2 V l eC Investigation Criteria - Direct 21500 Investigation Criteria - Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8540001
Attachment 3 Investigation February 28, 2008 Survey Unit F8540001 (none required)
Attachment 4 Data Assessment February 28, 2008 Survey Unit F8540001
CF8540001 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1 00cm2 2,000 0 1,800 1,600 --
1,400 -
1,200 -
1000 - -- -
8004- " - -~ - -- - -- - -- ~-
In70 0 20 40 60 80 100 Percentile
- Direct Measurements (dpm/1 00cm2) median - - - 75th Percentile - - - - 50th Percentile
CD w"3 2 P8540001 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmI!00cm" 2500 2000 E - - - - - - - - °-------------------------------- --- 1772 1500
- E V - - -0 - - 785 to0 500 0 CD CDC 0 . . . . . . . . . . ... . . . . . . .
- a. .. -. .- . . . .-202
-500!
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aa ~C0 0 a a C 0 a a a C 0aCa a a a 0 a 0 aC 0 2a- U X 22222X 22222 X2 Measurement Locations 1o Gross Activity - Average - - "+3StDev" - - %-3StDev" 0:
F8540001 Gross Activity Frequency Plot 2
DCGL = 43000 dpm/l 00cm 13 12 11 10 9
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Bins - Upper End Value (dpm/lOOcm2)