ML090890727
| ML090890727 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/27/2008 |
| From: | Ellen Brown Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097, F8260031 | |
| Download: ML090890727 (19) | |
Text
Rancho Seco Final Status Survey Summary Report October 27, 2008 Turbine Sumps Piping Survey Unit F8260031 Prepared By: *jt/-) i. / _*Dr Date: 1/01.2l /cZ&
FSS Engineer Reviewed By: Date: kk]Date:A4(e Lead FSS Engineer Approved By:________________ Date:_
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F826003 1, Turbine Sumps Piping Survey Unit
Description:
Operating History: This system collected clean water leakage and condensate from the turbine and routed it to the drain tank. This system was contaminated by radioactive system leakage into steam, feed and cooling water systems. Operating records and the HSA document occurrences of radioactive contamination associated with this system piping.
Site Characterization: Direct measurements were made of the interior surfaces of the system piping which confirmed the presence of plant-derived radionuclides. Direct measurements of the interior showed a mean gross activity level of 56,208 dpm/100 cm 2 and a maximum value of 680,000 dpm/100 cm2 . Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the system was determined to be a Class 1 system.
HSA Events: ODR-800111, 871122.
Page .2 of 7 FSS Summary Report F8260031
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 2 m 2 were scanned for 100% 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 3 of 7 FSS Summary Report F8260031
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:. F826 Turbine Sumps Piping Survey Unit: 0031 Structure Surface Class: 1 LTP Table 5-4 SU Area (m2): 2 Evaluator: Erin L. Brown DCGL (dpm/100 cm 2): 100000 Gross Activity DCGL Area Factor: 1 Class 1 Design DCGLemc 100000 Class 1 (dpm/100 cm 2):
LBGR (dpm/1 00 cm2): 50000 Default - 50% DCGL Design Sigma (dpm/100 cmr): 23464 Type I Error: 0.05 Type II Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m2): N/A Class 1 2
Scan Area (m ): 2 Scan Coverage (%): 100% Class 1 ZI.,P 1.645 1.645 Sign P: 0.97725 Calculated Relative Shift: 2.2 Relative Shift Used: 2.2 Uses 3.0 if Relative Shift is
>3 N-Value: 12 Design N-Value +20%: 15 NUREG-1575 Table 5-5 Design Min Samples N: 15 Class 1 Grid Spacing L: 0.3 Class 1 Page 4 of 7 FSS Summary Report F8260031
.Survey Results:
A total of 30 direct measurements were made in F826003 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 measurements indicated areas of elevated activity.
Scan activity ranged from 1660 to 2208 dpm/100 cm2 , based on the pipe detector efficiency.
Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/100 cm F8260031-MOO01GI 2117 F8260031-M0002GI 2091 F8260031-MOO03GI 2096 F8260031 -M004GI 2190 F8260031-MOO05GI 1897 F8260031-M0006GI 1786 F8260031-MOO07GI 1752 F8260031-MOO08GI 1876 F8260031-MOO09GI 1846 F8260031-MOOOGI 1713 F8260031-MOO11GI 1660 F8260031-MOO12GI 1784 F8260031-MOO13GI 2053 F8260031-Moo14GI 2058 F8260031-MOO15GI 2130 F8260031-MOO16GI 2208 F8260031-MOO17GI 2087 F8260031-MOO18GI 2051 F8260031-MOO19GI 2112 F8260031-MOO20GI 2018 F8260031-M0021GI 2035 F8260031-M0022GI 2082 F8260031-M0023GI 2067 F8260031-M0024GI 2088 F8260031-M0025GI 2095 F8260031-M0026GI 2103 F8260031-M0027GI 2006 F8260031-M0028GI 2033 F8260031-M0029GI 2025 F8260031-MOO30GI 2158 Mean: 2007 Median: 2056 Standard Deviation: 147 Range: 1660-2208 Page 5 of 7 FSS Summary Report F8260031
Survey Unit Data Assessment:
The survey design required 30 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.
Table 4. Data Assessment Results Survey Results Parameter Value Comment 2
Material Background Used (dpm/100 cm ): N/A 2
Ambient Background Used (dpm/100 cm ): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 30 Median (dpm/100 cm 2): 2056 Mean (dpm/100 cm 2): 2007 Direct Measurement Standard Deviation 147 (dpm/100 cm 2):
2 Total Standard Deviation (dpm/100 cm ): 147 Based on samples and backgrounds.
Maximum (dpm/100 cm 2): 2208 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 30 S+ Value: 30 Critical Value: 20 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: Yes Class 1 Total Standard Deviation <= Sigma: Yes Pass the Sign Test? Yes Reject the Null Hypothesis? Yes Does the Survey Unit Pass All Criteria? Yes Page 6 of 7 FSS Summary Report F8260031
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 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 1 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.- Therefore the EMC criterion was met.
==
Conclusion:==
The FSS of.this survey unit was properly designed as a Class 1 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 the LTP for pipe surveys. No direct measurements 2
exceeded the DCGL of 100000 dpm/l100 cm or the grout limit of 21000 dpm/1l00cm2 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 F8260031 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F8260031
Attachment 1 Maps October 27, 2008 Survey Unit F8260031
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Location of Turbine Buildinc inside the Industrial Area 00
- N Z Map F8260031-1, Turbine Building (+) O' Elevation Location of Turbine Building at Rancho Seco site
48'-4" 7' ~33*-7' '-5 I '1 0 97' 7'9 4'- 1' 11. -2"-* 4 ipe #5
-in .d iam e te rP i e #P 6 f.ig h6-In.
le pe 2 diam eter IJ l '4-in. diam eter ,
1.6 ft. in length '-"1.6 ft. in length "
HP,PedestaJ No~rth///A ' HP Pedestal No rth///1 00 C) o o.5 1.0 1.5 2.0 Map F8260031-2, Turbine Building Sump Drains Distance in Meters T.- *l I n;. A. 1). , . dr IItn* f 4
ta p ng rea: square me ers
East End of Main Feed Pump Area Map F8260031-3, Turbine Building Sump Drains Locations of Pipes 1 through 4 Page 4 of 5 Att. 1 Maps F8260031
JII 00 ON West End0ot Main Area B-een SprUMp Map F8260031-4, Turbine Building Sump Drains Locations of Pipes 3 through 5
Attachment 2 Instrumentation October 27, 2008 Survey Unit F8260031
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cm2 ) (dpm/100 cm2 )
M2350; 189081 44-157; 201250 1750 N/A Table 2-2. Investigation Criteria and DCGL Value d aluc Parameter (dpmn/100 cm2)
Investigation Criteria - Direct 100000 Investigation Criteria - Scan N/A DCGLw 100000 DCGLEMC 100000 Page 2 of 2 Att. 2 Instrumentation F8260031
Attachment 3 Investigation October 27, 2008 Survey Unit F8260031 (none required)
Attachment 4 Data Assessment October 27, 2008 Survey Unit F8260031
CD F8260031 Gross Activity Sample Results Quantile Plot 2
DCGL = 100000 dpm/1OOcm 2,500 2056 2,000 0
1,500 I
4-3 1,000 CD U
500 0
0 20 40 60 80 100 Percentile 00
- Direct Measurements (dpm/l00cm2) -median - _ -75th Percentile . 50th Percentile C')
(D U) 0 4ý1 F8260031 Gross Activity Sample Results Scatter Plot DCGL = 100000 dpml00cm= 2 3000 "2500 I- - 2447 E
0 . 0 0 0 0 0000.,oo,° c..* _..o° ..° oo.. * *o
- .._ 0 8 2000 0 0
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2007 0 ,n coo O- = 2,- .2. 0 E 1567 E 1500 C.'.
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Lo Gross Activity - Average - - "+3StDev" - - "-3StDev7 0
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0 F8260031 Gross Activity Frequency Plot DCGL = 100000 dpm/1 00cm2 9
8 7
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~I1 00 0r Bins - Upper End Value (dpm/1 00cm2)
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