ML082620164
| ML082620164 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 07/30/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-064 F8130471 | |
| Download: ML082620164 (28) | |
Text
Rancho Seco Final Status Survey Summary Report July 1, 2008 AB -Pump Alley column 11.7 south above -25'7" elevation Survey Unit F8130471 Prepared By: Dan A. Tallman Date: July 2, 2008 FSS Engineer Reviewed By: Date: Lead FSS Engineer Approved By: e<- e Date: 7-3 0 Fo Dismantlement Sbperintendent, Radiological FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit: F8130471, AB -Pump Alley column 11.7 south above -25'7" elevation Survey Unit
Description:
Operating History: The Auxiliary Building is a reinforced concrete structure that contained the RadWaste processing and supporting systems. The building contained six main elevations.
Residual radioactive material was known to be present on all levels of the interior of the building.
Operating records and the HSA document several events with the potential for a release of radioactivity inside this structure.
Site Characterization:
Direct measurements were made of each of the interior elevation surfaces as well as the exterior surfaces of the structure.
These measurements confirmed the presence of plant-derived radionuclides.
Direct measurements on the -29' elevation showed a mean gross activity level of 544,756 dpm/1 00 cm 2 and a maximum value of 11,370,000 dpm/100 Cm 2.Based on the classification procedure (DSIP-0020) and levels of gross activity reported, Survey Unit 813047, within the interior of the auxiliary building was determined to be a Class 1 area.HSA Events: HSA Report pg. 63.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 280.9 m 2 were scanned for 100% coverage.
Samples of removable contamination were collected at each direct ineasurement 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 9 FSS Summary Report F8130471 Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F813 Survey Unit: Class: SU Area (m2): Evaluator:
DCGL (dpm/100 cm'): 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 (%): ZI., : Sign P: Calculated Relative Shift: Relative Shift Used: N-Value: Design N-Value + 20%: Design Min Samples N: Grid Spacing L: 0471 1 280.9 D.A.Tallman 43000 3.5 154370 21500 10204 0.05 0.05 Cs-137 6.85 280.9 100%1.645 1.645 0.97725 2.1 2.0 12 15 41 2.6 AB -Pump Alley column 11.7 south above -257" elevation Structure Surface LTP Table 5-4 Gross Activity DCGL Class I Class 1 Default 50% DCGL Class 1 Class I Uses 3.0 if Relative Shift is>3 NUREG-1575 Table 5-5 Class 1 Class 1 Page 3 of 9 FSS Summary Report F8130471 Survey Results: A total of 43 direct measurements were made in F8130471.
The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. Two of the scan measurements indicated areas of elevated activity.
Beta Scan activity ranged from 2409 to 12410 dpm/100 cm 2 , based on a surveyor efficiency of 0.5 and no background subtracted.
In-vivo gamma scans of two grids (13 and 49) exceeded the investigation level with observed activities of 71,800 dpmr100 cm 2 , and 68,600 dpm/100 cm 2 respectively.
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..Page 4 of 9 FSS Summary Report F8130471 Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/lO0 cm F8130471-CO001BD F8130471-CO002BD F8130471-CO003BD F8130471-CO004BD F8130471-CO005BD F8130471-CO006BD F8130471-CO007BD F8130471 -CO008BD F8130471 -CO009BD F8130471-Co01OBD F8130471-CO011BD F8130471-Co012BD F8130471-Co013BD F8130471-Co014BD F8130471-Co015BD F8130471-Co016BD F8130471-Co017BD F8130471-CO018BD F8130471-CO019BD F8130471-CO02OBD F8130471-C0021 BD F8130471-CO022BD F8130471-CO023BD F8130471-CO024BD F8130471-CO025BD F8130471-CO026BD F8130471-CO027BD F8130471-CO028BD F8130471-CO029BD F8130471-CO03OBD F8130471-CO031BD F8130471-CO032BD F8130471-CO033BD F8130471 -CO034BD F8130471-CO035BD F8130471-CO036BD F8130471-CO037BD F8130471-CO039BD F8130471-CO04OBD F8130471-CO041BD F8130471-Cc042BD F8130471-CO043BD Mean: Median: Standard Deviation:
Range: 1888 2039 1561 1764 1364 1302? 4648 2563 1836 3128 2277 1841 3185 1940 1867 1914 1826 1758 2199 1727 1582 1847 1862 1385 1561 2075 1608 1769 1722 1484 1930 1826 1644 2552 2153 1743 4274 2557 4082 2910 2324 6795 3377 2272 1867 1045 1302-6795 Page 5 of 9 FSS Summary Report F8130471 Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2)F8130471 COOOI SM F81 30471 C0002SM F8130471CO003SM F8130471 C0004SM F8130471 COOO5SM F8130471CO006SM F8130471 C0007SM F8130471CO008SM F8130471CO009SM F8130471Co010SM F8130471CO01ISM F8130471CO012SM F8130471CO013SM F8130471CO014SM F8130471CO015SM F8130471CO016SM F8130471CO017SM F8130471CO018SM F8130471C0019SM F8130471 C0020SM F8130471C0021SM F8130471 C0022SM F8130471CO023SM F8130471CO024SM F8130471C0025SM F8130471CO026SM F8130471 C0027SM F8130471 C0028SM F8130471 C0029SM F8130471 C0030SM F8130471C0031SM F8130471 C0032SM F8130471 C0033SM F8130471C0034SM F8130471 C0035SM F8130471CO036SM F8130471C0037SM F8130471C0038SM F8130471 C0039SM F8130471 C0040SM F8130471 C0041SM F8130471 C0042SM F8130471 C0043SM Mean: Median: Standard Deviation:
Ranqe:-2.24-0.95-3.53-0.95 6.8-2.24 301.25 42.96 10.68 6.8 14.55 4.22 37.8 21.01 11.97 72.67 128.2 27.46 94.62 26.17 5.51 45.55 11.97-0.95 10.68 77.83 4.22 4.22 1.64 26.17 1.64 73.96 39.09 4.22 6.8 32.63 0.34 15.84 24.88 22.3 8.09-0.95 9.38 28.43 10.68 51.46-3.53 to 301.25 Page 6 of 9 FSS Summary Report F8130471 Survey Unit Data Assessment:
The survey design required 43 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.SPage 7 of 9 FSS Summary Report F8130471 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): 43 Median (dpm/100 cm 2): 1867 Mean (dpm/l00 cm 2): 2272 Direct Measurement Standard Deviation 1045 (dpm/100 cm 2): Total Standard Deviation (dpm/100 cm 2): 1045 Based on samples and backgrounds.
Maximum (dpm/100 cm 2): 6795 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 43 S+ Value: 43 Critical Value: 27 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 8 of 9 FSS Summary Report F8130471 Survey Unit Investigations and Results: Two (2) investigations (scan grids GS 13 and GS49) were required for the scan measurements and the results are reported in Attachment
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. Potential areas of elevated activity were detected and evaluated as shown in Attachment
- 3. 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 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. The investigations required were performed and documented.
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 F8130471 meets the release criteria of 10CFR20.1402.
Page 9 of 9 FSS Summary Report F8130471 Attachment 1 Maps July 1, 2008 Survey Unit F8130471 0 A (j)K-)7 C-,-~-4 _a--re.Reflected CeWQ cj~, ~- 1 K-)T C2I_1 ITI I----- J.Not Inthis sulvy EastWal 49,-3--ELC-V 0 ELEV. 25.C I~~ r~ I>(ELEV -Z'5- 9" South Wal West Wall 49,-3" Eli 00 w-, 0...Surface Area Estimates; Reflected Ce,1 -504m'East Wal 106.3 rn, South Wal 24 2,r West Wal -100.0 rnm TOTAL AREA 280.9 rn'* SMU13 SACRAMENTO MUNICIPAL UTILITY DISTRICT AUXILIARY BUILDING PUMP ALLEY GENERAL AREA SURFACE ESTIMATES SOUTH OF COLUMN LINE 11.7 F81 30471 -MI DWG: 81300.02d SHEET 1 of i T C HILL W 00 u0--._...: ...Tw T T -Z T -N w..... ... ............. ..........
.. ..tI--l- i-I-t-H -I-I-I-H I-,-,II I.I?;II- I I- I- I-I-H-I I -I I I -I I- I llllllll~~~~~ .II .... .,,, .III ....l .I II .I; I I .,,i I .Ti ... ... ...I-AHAI H---A----IIIHIII--- -H-I-----T , }-H-I+I-H H+-IIH --4IH-+/-4--....._. .: _ .-.f _ +.... .. ... .. .. .. .. .... ..............% ... ................. ........ .... ...... ....... ..... ....:. w: H-I- I-I-I.-H -H-H -H -. T ..H.LL... ..~ ..........
-, .-H -?........
.... :.....4 .. .......* ~~ T.'l _-, i A i * H-II-r-H ~*H- j~-'-I HA SM~Hi fli COLUMN LIN 11. H BETA DIEC/LOS SURFACE.....
ACIIT.ANO.SAT.OATO SAR ME1........
FS 30471.-M UTLT OITRC___ _ __ _ __ _ ___ __ __ __ __ __ ___ _ WO 830.0d SEE 1oH TC IL (D 0T C-)Reflected Coin SCALE I"= 1 -0" METER SCALE 0 1 2 3*5mu SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDIG. PUMP ALLEY SOUTH OF COLUMN LINE 11.7 -BETA DIRECT/LOOSE SURFACE ACTIVITY MEASUREMENT LOCATIONS F81 30471 -M2 DWG: 81300.02d SHEET2of4 I C HILL GQ 0 FIFV-,-r?
I -9 6k 1 G.(5) (D\ /G~ GD -1,0t (FD GD-n~ELEV. -25*-g -ELEV -254,' -2'-r NtPrt Of Ths Sura 117111s////-I-East:Wall South Wall~I1 00 w SCALE I= 1,-0 METER SCALE 0 1 2 3*smun SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH OF COLUMN LINE 11.7 -BETA DIRECT/LOOSE SURFACE ACTIVITY MEASUREMENT LOCATIONS F81 30471 -M2 DWG: 81300.02d SHEET3of4 T C HILL 0 04$)kJ3)ELEV. IO ELEV. -25'-9" ELEV. -29*-O"-t GD GD I ~ GD GD GD GD 1w-B- @GD GD GD-----4...... -W: '0; in GD GD i I i West Wallýr1 00 40-,4 SCALE I" = 1,-0.METER SCALE 0 1 2 3*5MUn SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH OF COLUMN LINE 11.7 -BETA DIRECT/LOOSE SURFACE ACTIVITY MEASUREMENT LOCATIONS F8130471 -M2 DWG: 81300.02d SHEET4of4 T C HILl L 0 0-Realected Cegnu coo 00 SCALE 1, =-0".METER SCALE 0 1 2 3* mun SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH OF COLUMN LINE 11.7 SCAN MEASUREMENT LOCATIONS
(.GAMMA.)F81 30471 -M3 DWG: 81300.02d SHEET 1 of 4] C HILL OWG:8130.02 SHET 1 f4T C HILL (DQ 00 0©03)East Wall South' Wall 00 w-.SCALE S= 1'-O" METER SCALE 0 1 2*s U-SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH OF COLUMN LINE 11.7 SCAN MEASUREMENT LOCATIONS (GAMMA)F81 30471 -M3 DWG: 81300.02d SHEET 2 of4 I T C HILL OWO: 81300.02d SHEET2of4 I C HILL 0 W West Wall Gamma ScanCentered at One Meter will be Evaluated in F8130461 q; u-c )> LL"4J 00 SCALE METER SCALE 0 1 2 3 OM* U SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH OF COLUMN LINE 11.7 SCAN MEASUREMENT LOCATIONS (GAMMA)F81 30471 -M3 IDWG: 81300.02d
'SHEET 3 of4 T C HILL I DWG: 81300.02d SHEET3of4 I C* HILL 0 001 002 003 C"J C C) 0I c L,/004 005 006 Sides of Ceiling Opening CEILING PLUG CAVITY DETAIL ti I-Il 00 w~SCAL.E 114" V1-0" MEFERSCALE
- SMU1 SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH, OF COLUMN LINE 11.7 SCAN MEASUREMENT LOCATIONS (BETA)F81 30471 -M3 0 1 2 3 DWG:. 81300.02d SHEET 4 of 4 I C: HiLL DWG:8130.02 SHET 4 f 4T C -iILL 0 00 w 001.0 0 Sides of Ceiling Opening CEILING PLUG CAVITY DETAIL SCALE 1I4" = I-O" METER SCALE*SMU13 SACRAMENTO MUNICIPAL UTILITY DISTRICT AUX. BLDG. PUMP ALLEY SOUTH OF COLUMN LINE 1 1.7 JUNCTURE SCAN LOCATIONS F8130471 -M4 0 1 2 3 DWG: 81300.02d SHEET 1 of 1 T C HILL DWG: 81300.02d SI-IEETloIi T C HILL Attachment 2 Instrumentation July 1, 2008 Survey Unit F8130471 Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cm') (dpm/100 cm 2)M2350; 149789 43-68B; 161397 433 1033 M2350; 149789 43-116-1B; 256006 A 437 739 Tennelec; 0401171 N/A 6 dpm a, 12 dpm -3 "N/A A Juncture Instrument Detector MDC I (dpm/100 cm=)Model; Serial No. Model; Serial No.1580 (Co60)ISOCS 1983920 1400 (Cs 137)3920_2mconcrete geometry 12.5 m 2 FOV Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm 2)Investigation Criteria -Direct 154370 Investigation Criteria -Scan 154370 DCGLw 43000 DCGLEMc 154370 Value (dpm/100 cm 2)To detect a 1 m hot spot at the EMC Criterion within the detector field of view 63,300 dpm/100 cm 2 Cs-137 21,275 dpm/100 cm 2 Co-60 3920_2mconcrete geometry 12.5 m2 FOV 2 Investigation Level set at 43,000 dpm/lOOcm 2 Cs-137, ND Co-60 for investigation within survey instructions, revised during data evaluation based on LFSSE recommendation.
Page 2 of 2 Att. 2 Instrumentation F8130471 Attachment 3 Investigation July 1, 2008 Survey Unit F8130471 Table 3-1 Survey Unit Investigation Inigoal Investigation Elevated Investigation -DCGLemrc Investigation Result Area DCGLemc Result Unity Grid (dpValuem Area/10 Factor Level (dpm/cm0 cm)) (dpm/100 (cpm) (M 2) (dpm/l OOcm 2) Fraction________ ICM2) j GS13 63,300 dpm/100 cm 2 75,8003 1,5552 NA NA NA 11,4061 NA.Cs-137 GS49 21,275 dpm/100 cm 2 71,8003 1,5573 NA NA NA 11,4192 NA Co-60 Comments: 1 Average of BS01-05 taken within boundaries of elevated measurement.
2 Average of BS06-10 taken within boundaries of elevated.
measurement.
3 Total activity as calculated on F8130471 -Scan Sample Results worksheet (Co60/Csl37 summation)
Survey Unit Remainder DCGL = SU Mean = 0.053 43,000 2,272 EMC Unity Sum 0.053 Page 2 of 2 Att. 3 Investigation F8130471 Attachment 4 Data Assessment July 1, 2008 Survey Unit F8130471 GO CD F8130471 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1 00cm 2 I 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 0 1867-,F 0 20 40 60 Percentile 80 100 0* Direct Measurements (dpm/ll00cm2)
-median --75th Percentile
--- -50th Percentile 0Q 0>C)('a-3 O77 F8130471 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpml00cm 2 , 00ft N E E 8000 7000 -6000 -5000 -4000-3000-2000-1000 -1000--2000 0 00 0 0 0 0 0 0 0 0o (0 0 O0 WM "c 0 00 0 0 00000 0'0000 .0.0 0 00 0 0 aOa -a0- aaaa-aaa a.5407 2273-854 4 I I 00 0000 0 000 000000000 00 0 00 00 0 00 0000000 000 000 MuMwMTwwwwwMMwmwuuowwwwwmwummnmwwwawmwmtmu~wwmtm ooououuooooo=ooooouMoeosoooomoLoooooo ooan Measurement Locatons i G "l 1 o Gross Actlvity--'-
Average- "+3StDev" --"ý-3SDev" CD)~-41 00 F81 30471 Gross Activity Frequency Plot DCGL = 43000 dpm/100cm 2 C W v-LL 0 j 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 9o i to Bins -Upper End Value (dpm/1 00cm2)