ML081580597
| ML081580597 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/08/2008 |
| From: | Ellen Brown Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| F8990511 | |
| Download: ML081580597 (17) | |
Text
Rancho Seco Final Status Survey Summary Report March 3, 2008 Carbon Dioxide System Piping Survey Unit F8990511 Prepared-By: { / Date: 3*i1/3o, 2:
FSS Enqjnmee Reviewed By:. Date" Approved By: Date:
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F899051 1, Carbon Dioxide System Piping Survey Unit
Description:
Operating History: This system transported liquid carbon dioxide for fire protection in areas of the site in which water could not be used. This system was designed to be clean.
Operating records and the HSA document no occurrences of radioactive contamination associated with this system piping. In addition, the system was maintained at or above atmospheric pressure which prevented any contamination from entering the system.
Site Characterization: Direct measurements were made of the interior surfaces of the system piping which confirmed the absence of plant-derived radionuclides. Direct 2
measurements of the interior showed a mean gross activity level of 8,585 dpm/l100 cm and a maximum value of 23,654 dpm/100 cm2 . Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the system was determined to be a Class 2 system.
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 spaced at 15cm intervals and 1.8 m2 were scanned for approximately 72%
coverage. 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 F8990511
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F899 Carbon Dioxide System Piping Survey Unit: 0511 Structure Surface Class: 2 LTP Table 5-4 SU Area (m2): 2.5 Evaluator: Erin L. Brown DCGL (dpm/100 cm 2): 100000 Gross Activity DCGL Area Factor: N/A Class 2 Design DCGLemc N/A Class 2 (dpm/100 cm 2):
2 LBGR (dpm/100 cm ): 50000 Default 50% DCGL Design Sigma (dpm/100 cm ):2 .8930 Type I Error: 0.05 Type II Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m): 3 Class 2 Scan Area (m 2 ): 1.8 Scan Coverage (%): 72% Class 2 ZI-. 1.645 1.645 Sign P: 0.99865 Calculated Relative Shift: 5.6 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 2 Grid Spacine L:
A 0.4 Class 2 Page 3 of 8 FSS Summary Report F8990511
Survey Results:
A total of 40 direct measurements were made in F89905 11. 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 1655 to 2275 dpm/1 00 cm 2, based on the pipe detector efficiency.
Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/100 cm F8990511-MOO01GI 1925 F8990511-MOO02GI 1742 F8990511-MOO03GI 1858 F8990511-MOO04GI 1963 F8990511-MOO05GI 1854 F8990511-MOO06GI- 1767 F8990511-MOO07GI 1796 F8990511-MOO08GI 1655 F8990511-MOO09GI 1714 F8990511-MOOlOGI 1944 F8990511-MOOIIGI 1957 F8990511-MOO12GI 1897 F8990511-MOO13GI 2050 F8990511-MOO14GI 1882 F8990511-MOO15GI 1925 F8990511-MOO16GI 1828 F8990511-MOO17GJ 2196 F8990511-MOO18GI 1981 F8990511-MOO19GI 1888 F8990511-MOO20GI 1834 F8990511-MOO21GI 1740 F8990511-M0022GI 1908 F8990511-M0023GI 1852 F8990511-M0024GI 1866 F8990511-M0025GI 1912 F8990511-M0026GI 1796 F8990511-M0027GI 1712 F8990511-M0028GI 1838 F8990511-M0029GI 2043 F8990511-MOO30GI 1761 F8990511-MOO31GI 1716 F8990511-M0032GI 2024 F8990511-M0033GI 2011 F8990511-M0034GI 2131 F8990511-M0035GI 2097 F8990511-M0036GI 2103 F8990511-M0037GI 2248 F8990511-M0038GI 2275 F8990511-M0039GI 2254 F8940511-MOO40GI 2207 Page 4 of 8 FSS Summary Report F8990511
Mean: 1929 Median: 1903 Standard Deviation: 164 Range: 1655-2275 Page 5 of 8 FSS Summary Report F8990511
Survey Unit Data Assessment:
The survey design required 40 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 F8990511-
Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpmlO00 cm 2): N/A Ambient Background Used (dpm/100 cm2): N/A Average Ambient BKG 0 Actual Direct Measurements (N): 40 Median (dpm/100 cm 2): 1903 Mean (dpm/100 cm 2): 1929 Direct Measurement Standard Deviation 164 (dpm/100 cm 2):
Total Standard Deviation (dpm/100 cm 2): 164 Based on samples and backgrounds.
Maximum (dpm/100 cm 2): 2275 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 40 S+ Value: 40 Critical Value: 25 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: N/A Class 2 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 F8990511
Survey Unit Investigations and Results:
No investigations were required 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), the ALARA criterion has been met.
Changes in Initial Survey Unit Assumptions:
The survey unit was designed as a Class 2 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 2 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 100000 dpm/100 cm 2 or the grout limit of 21,000dpm/100cm 2 . 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 F899051 1 meets the release criteria of I0CFR20.1402.
Page 8 of 8 FSS Summary Report F8990511
Attachment 1 Maps March 3, 2008 Survey Unit F8990511
CD rtQ 0
E081360 E0513877 N1883624 NI 8S674 KEY PLAN LEGENP UNDERGROUND
.REMAINING RMVDPPINd CONTNNMFT 00 PIPINGSIJMK%4AJI 32 LENG 6EA CARBRON DIOXIDE GAS 4*'0 20 LF. I2SM 1-0 201Y .5SSI UND ERG. ROU ND PIPING Il I ~3 F899,051 Sir-1 -M 1 OF . I RC
Attachment 2 Instrumentation March 3, 2008 Survey Unit F8990511
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cm 2 ) (dpm/100 cm2 )
M2350; 189081 44-159; 199736 2860 N/A Table 2-2. Investigation Criteria and DCGL Value P a ra m e te r 'V (dpm/100
.a u cm 2 CM )
Investigation Criteria - Direct 100000 Investigation Criteria - Scan N/A DCGLw 100000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8990511
Attachment 3 Investigation March 3, 2008 Survey Unit F8990511 (none required)
Attachment 4 Data Assessment March 3, 2008 Survey Unit F8990511
F8990511 Gross Activity Sample Results Quantile Plot 2
0 DCGL = 100000 dpm/lOOcm 2,500 2,000 1903 I. 1,500 3m 1,000 CD~
500 0
0 20 40 60 80 100 Percentile It 0
- Direct Measurements (dpm/1 00cm2) -median - - - 75th Percentile - - - - 50th Percentile
ct~
F8990511 Gross Activity Sample Results Scatter Plot 0 2 DCGL = 100000 dpm/1OOcm 3.000 -i p'2500-2421 E 0000000000 0 00 2000 0
=. 0", - . ..
0lll 0 I 1 .0 mm* .Q.0 0 0 00 00 1929 0O0 0 0 EL 1500 I - - - - - - - - - - -. - - - - - - - - - - - - - - - - - - - - 1436 Cl)
Cl) S1000 (1)
< 500 0 I II I II liii II I 0000000000000000000000000000000000000000 Measurement Locations 00 0
0 Gross Activity - Average - - "+3StDev" - - "-3StDev"l
0 F899051 1 Gross Activity Frequency Plot DCGL = 100000 dpm/1 00cmr 9
8 7 -4.
6 a)
Ci 5
-4.
4 00 3
2 1
0 0 ~1~ ~1~ ~1~ ~1~
ZIZIELI ILO N.
I'D Bins - Upper End Value (dpm/1 00cm2)