ML090900772
| ML090900772 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/26/2009 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097 | |
| Download: ML090900772 (25) | |
Text
Rancho Seco Final Status Survey Summary Report February 26, 2009 Tank Farm -BWST pad Survey Unit F8100043 Prepared By: Dan A. Tallman A_______________
Date: February 26, 2009 FSSEngin/eer Reviewed By: J l & t ,
-[3(30 Lead FSS Engineer Approved By: t1 Date: Dismantlement(Superintendent, Radiological FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit: F8100043, Tank Farm -BWST pad Survey Unit
Description:
Operating History: This survey unit consists of the concrete pad that supported the Borated Water Storage Tank (BWST), used to store radioactive liquids. Operating records and the HSA document several events with the potential for a release of radioactivity associated with this survey area. The HSA documented the storage of radioactive material within the area that may have had the potential to contaminate the area.Several locations adjacent to the designated pad required remediation as did the majority of the pad itself.Site Characterization:
Soil samples surrounding the pad were collected and analyzed for the presence of plant-derived radionuclides.
Cs-137 was the primary nuclide of plant origin detected.
The BWST pad was surveyed by with a mean activity level of 11,992 2 2 dpm/100 cm 2 and a maximum value of 140,880 dpm/100 cm .Based on the classification procedure (DSIP-0020) and levels of Cs-137 reported, the BWST Pad was determined to be a Class 1 area.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 determined using a random-start, fixed grid pattern and 187 m 2 were scanned for 100% 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 F8100043 Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: Survey Unit: Class: SU Area (m2): Evaluator:
DCGL (dpm/100 cm 2): 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 (M 2): Scan Coverage (%): Zl-,, :: Sign P: Calculated Relative Shift: Relative Shift Used: N-Value: Design N-Value + 20%: Design Min Samples N: Grid Spacing L: F810 0043 1 187 D.A.Tallman 43000 3.5 153669 21500 12845 0.05 0.05 Cs-137 6.9 187 100%1.645 1.645 0.945201 1.6 1.6 14 17 27 2.6 Tank Farm -BWST pad Structure Surface LTP Table 5-4 Gross Activity DCGL Class 1 Class I Default 50% DCGL Class 1 Class 1 Uses 3.0 if Relative Shift is>3 NUREG-1575 Table 5-5 Class 1 Class 1 Page 3 of 8 FSS Summary Report F8100043 Survey Results: A total of 27 direct measurements were made in F8100043.
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 1754 to 20819 dpm/100 cm 2 , 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)F8100043-CO001BD F8100043-CO002BD F8100043-CO003BD F8100043-CO004BD F8100043-CO005BD F8100043-CO006BD F8100043-CO007BD F8100043-CO008BD F8100043-CO009BD F8100043-COOIOBD F8100043-COOI1BD F8100043-C001 2BD F8100043-CO01 3BD F8100043-CO014BD F8100043-CO01 5BD F8100043-CO01 6BD F8100043-CO017BD F8100043-CO018BD F8100043-CO019BD F8100043-C0020BD F8100043-C0021 BD F8100043-CO022BD F8100043-CO023BD F8100043-C0024BD F8100043-CO025BD F8100043-C0026BD F8100043-CO027BD Mean: Median: Standard Deviation:
Range: 1976 1940 2791 2231 2007 2033 2039 2158 2044 2111 1966 2065 2023 2065 2080 2153 2065 1950 2256 2033 2054 1987 2142 2158 2085 2205 1779 2089 2065 172 1779 -2791 Rag:17929 Page 4 of 8 FSS Summary Report F8100043 Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2)F8100043C0001 SM F8100043C0002SM F8100043C0003SM F8100043C0004SM F8100043C0005SM F8100043C0006SM F8100043C0007SM F8100043C0008SM F8100043C0009SM F8100043C0010SM F8100043C001 1 SM F8100043C0012SM F8100043C0013SM F8100043C0014SM F8100043C0015SM F8100043C0016SM F8100043C0017SM F8100043C0018SM F8100043C0019SM F8100043C0020SM F8100043C0021SM F8100043C0022SM F8100043C0023SM F8100043C0024SM F8100043C0025SM F8100043C0026SM F8100043C0027SM F8100043C0008SM F8100043C0023SM Mean: Median: Standard Deviation:
Range:-2.88-0.29 3.58 2.29 2.29 2.29 2.29-2.88 2.29-1.58-1.58 1 2.29 2.29-0.29-0.29 4.87 4.87-0.29 3.58 1 2.29-0.29 1 2.29 1 4.87 6.16-1.58 1.4 2.29 2.34-2.88 to 6.16 Page 5 of 8 FSS Summary Report F8100043 Survey Unit Data Assessment:
The survey design required 27 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 F8100043 Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2): N/A Ambient Background Used (dpm/O00 cm 2): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 27 Median (dpm/100 cm 2): 2065 Mean (dpm/100 cm 2): 2089 Direct Measurement Standard Deviation 172 (dpm/100 cm 2): Total Standard Deviation (dpm/100 cm 2): 172 Based on samples and backgrounds.
Maximum (dpm/100 cm 2): 2791 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 27 S+ Value: 27 Critical Value: 18 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 7 of 8 FSS Summary Report F8100043 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 unitaverage 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.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 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 F8100043 meets the release criteria of 1OCFR20.1402.
Page 8 of 8 FSS Summary Report F8100043 Attachment I Maps February 26, 2009 Survey Unit F8100043 C)C0 C)CST PAD .r °i 1o 3 DRC ST PAD r./H3 EVAP PAD .BWST PAD 1 I Zone 3 Asphalt ,--l.Zone 1 JTI IT"' DISTRI T TANK FARM -CONCRETE PADS GENERAL ARRANGEMENT PLAN VIEW F8100043-Mi SHEET 1 OF 2 (D C11'7 (1NI N J]/ /.///I/7' //K' /-ix"7 N j , Vertical Surface Details F 7w.\, \\\ \K\\ N'(N 7/7 7 N 7,/// .7 00 00 C C)BWST PAD Surfaco Aroa Esdmaias Tt~ni 187.5w'Scale Feet t = 1,-0" Scale Meters 0 1 2 3*0 S Mum SAC0AMENTO MUNICIPAL LUTI ITY, DISTR:CT TANK FARM -BWST PAD PLAN / ELEVATION VIEW SURFACE AREA ESTIMATE F8100043-Mi SHEET 2 of2 444-'44-li
.4 H'4 f44 'I4'414',r iitl44- 44ilWf HA4i +H ++i! C+I + if 4I f 44 1 4'44 i44~ 4*H4 f 44'- f 1+4-- ,i- ~j1- ýT 4+w a TT w TT I +T, T- T++11 1 44 al ....if.. F ~ 'I' .-- fHHH 4 .-A H .-~ 4H 4-f- 4-H+I-+ --+444-H-+H-4 1--4 H- -+ -111it 1iH i H I--4 4 H + 1 '--H-+'-'-4+H-[ 4Hi4--44 I 4-44-4fHH 011HI iiH iII i +-f I41 f: H lif m hHil-m w+-4 4-- + H~ .-+/-.-+4--' +/-4-+/-4-44-'
-4+-4-H-H4-4,-4--'
4-H H+'4-HH+4+
-'4+'4-44-P4+rH-4--
P+4--4-- 444T* 'H 4-,4 4--H-+'-T-+/-4--4-44-44p4+T 4- -4 4- 7__ _ _ _4 4:~w T 1 4-i+ + 4- -_-PAD~~ ~~ TAKFR-BST A TIIE T' (D (A 0 ýC)Nm/ /23d/24 25 26 27 20 V22 21~5ý09 Isv06 08 0002 81-61 ýV7 03-'1l7 10/2\ /~-7/*>1 04/01 00 0 BWST PAD Scale Feet I -0" Scale Meters 0 1 2 3 WSACRAM"ENTO H' INICIPAL UTILITY( OISTR C'TANK FARM -BWST PAD BETA DIRECT MEASUREMENT LOCATIONS F8100043-M2 SHEET 2 of2 025 026 027 028 029 030 031 032 t03".N'o0 0 C)>N ,.024 007 023 006 204 022/'.107 211 203/021 ___ _____078 26 210 202 0201 079 215 209 201 074 1 073 072 071 070 069 068 067 F + + F -, F 195 185 148 065 064 178 168 158 066\0 _ 'K \q34 063 \062 .060 061 57 126 194 : 184 177 167 157 147./'59 0568~-63 54 50"62 51/1-055 0 5 6 193 183 176 166 156 146 I ~ + F + F I +/- F 145 138 192 185 175 165 155 145 138 134 130 125 019 080 214 206 200 191 184 174 164 154 144 137 133 129 124 018 061 213 207 199 190 183 173 163 153 143 136 132 128 123 212 206 198 189 182 172 162 152 142 135 131 127 122 016 083 205 197 188 181 171 161 151 141 121 108 1 1 7 118 119ý_,036 A-038_--42--~043 ,-1 015 .~r4~04 085 196___ 109 __014\ \110 013\BWST PAD o4.,, 187 180 170 160 150 140 186 179 169 159 149) 139-~ F + + F 111 112 105 A48 4\ 107 45 .120\746/ t I 1o 6 103 104 2}~102 > 7/ 10 "., " 44_°"_ 0 4 ,ou001___ 0987 K irregular surfac 0___ 8i 113 1 117 115 116 091 092 093 094 095 i096 es\j I .010 009 008 007 006 005 004 003 00 C)C)C)Scale Feet."= 1'-0" Scale Meters 0 1 2 3 6 SINUD SACRAMENrO MUNUICPAL UTI LIY DISTRCT TANK FARM -BWST PAD BETA SCAN MEASUREMENT LOCATIONS F8100043-M3 SHEET 1 of4 (tD 0 0 15 <--- -..\0 \014\/BWST PAD 00 0 0 0 Scale Feet 8" 1'-0 Scale Meters 0 1 2 3 SACRAMENTO MUNICIPAL UTILITY DISTRiCT TANK FARM -BWST PAD BETA SCAN W/ 43-37 MEASUREMENT LOCATIONS F8100043-M3 SHEET 2 of4 025 026 027 028 029" 030 031 032 (D 00 0 0,21 0201 019 018 017 BWST 016 014, BWST PAD 00 0 0Scale Feet: 1-" Scale Meters 0 1 2 SACRAMENTO MUNIC PA.LJTH ITY DISTRiCT TANK FARM -BWST PAD BETA SCAN W/ ISOCS MEASUREMENT LOCATIONS F8100043-M3 SHEET 3 of4 C)N J,.//"/// \I BWST PAD Lo C)CD Scale Feet.I.........
Scale Meters 0 1 2 3*mu SA i-"WENTO M~UNICIPAL ORITY IPSTRICT TANK FARM -BWST PAD ISOCS GAMMA SCAN MEASUREMENT LOCATIONS F8100043-M3 S;IIELET4 of 4 Oq (D~(<N-A.i/ //N N\X//15 16 I 14 17 13 18 12 11 07 08 -06 09 -0/72 irregular surfaces indicate location of remaining
'lunctures"'N/BWST PAD'N N'00 0 0 0>Scale Feet1-r Scale Meters 0 1 2 3 TANK FARM -BWST PAD JUNCTURE SCAN MEASUREMENT LOCATIONS F8100043-M4 SIHEET of, Attachment 2 Instrumentation February 26, 2009 Survey Unit F8100043 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; 161406 433 1033 M2350; 175834 43-68B; 148634 433 1033 M2350; 203482 43-68B; 148453 433 1033 M2350; 175834 43-116-1B; 190642 796 3258 M2350; 189081 44-159; 238368 5250 N/A Tennelec; 0401171 N/A 5 dpm a, 9 dpm r3 N/A Table 2-2. Investigation Criteria and DCGL Value Parameter Valuc (dpm/1,00 cm2)Investigation Criteria -Direct 152901 Investigation Criteria -Scan 43,0001 DCGLw 43000 DCGLEMC 152901 IL set at DCGLw for conservatism Page 2 of 2 Att. 2 Instrumentation F8100043 Attachment 3 Investigation February 26, 2009 Survey Unit F8100043 (none required)
Attachment 4 Data Assessment February 26, 2009 Survey Unit F8100043 CD2 00 F8100043 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1OOcm 2 I 3,000 2,500 2,000 1,500 1,000 2065 500 0 0 20 40 60 80 100 Percentile I
- Direct Measurements (dpm/100crn2) -median ---75th Percentile
--- -50th Percentile I
-O FP100043 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmll00cm Ln 0 (C ryn (A, 30C S25C E 0 S20C 7-a. 15('100 5C 10 0-0 -C---a a ----a a --a ---a -a -a --a -a a a a 0 0-0 0 0 __0 0 00C ý0 r C0 IO -V 0 Tr- 0 0"-- --- 2-'° " 0 0 2505 2088 1572 10 10 o o o o o oooo 0O00O0OOO00000000 000000000 Measurement Locations 1 o Gross Activity -Average --"+3StDev" a a "-3StDev "i C/2 00 00 (D F8100043 Gross Activity Frequency Plot DCGL = 43000 dpm/1 00cm 2 20-18-0i 16-14-12-10-8-6 4 2 0 -+CA (1..Bins -Upper End Value (dpm/100cm2)