ML082620149
| ML082620149 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/12/2008 |
| From: | Tallman D A Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-064 | |
| Download: ML082620149 (34) | |
Text
Rancho Seco Final Status Survey Summary Report June 12, 2008 Aux. Bldg. Western Stairwell
(-47' to -20')Survey Unit F8130081 Prepared By: Dan A. Tallman _ Date: June 12, 2008 FSS Engineer Reviewed By 7'- J4. I ate: (4(,It)R Lead FSS Engineer Approved By: Date: 7- -o -0 Dismantlement Superintendent, Radiological FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit: F8130081, Aux. Bldg. Western Stairwell
(-47' to -20')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 -47' elevation showed a mean gross activity level of 320,071 dpm/100 cm 2 and a maximum value of 5,720,000 dpm/100 cm 2.Based on the classification procedure (DSIP-0020) and levels of gross activity reported, Survey Unit 813008 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 217 m 2 were scanned for 100% coverage.
Samples of remoyable 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 9 FSS Summary Report F8130081 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 2): Area Factor: Design DCGLemc (dpm#100 cm 2): LBGR (dpm/100 cm 2): Design Sigma (dpml 00 cm 2): Type I Error: Type II Error: Predominant Nuclide: Sample Area (m2): Scan Area (m 2): Scan Coverage (%): Zi-P Sign P: Calculated Relative Shift: Relative Shift Used: N-Value: Design N-Value + 20%: Design Min Samples N: Grid Spacing L: 0081 1 217 D.A.Tallman 43000 3.6 154800 21500 9976 0.05 0.05 Cs-137.6.9 217 100%1.645 1.645 0.97725 2.1 2.1 12 15 33 2.6 Aux. Bldg. Western Stairwell
(-47' to -20')Structure Surface LTP Table 5-4 Gross Activity DCGL Class 1 Class 1 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 9 FSS Summary Report F8130081 Survey Results: A total of 39 direct measurements were made in F8130081.
The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. Multiple scan measurements indicated areas of elevated activity.
Scan activity ranged from 1825 to 1750044 dpmr/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.Page 4 of 9 FSS Summary Report F8130081 Table 2. Direct Measurement Results Measurement ID Gross Activit (dpm/100 cm F8130081-COOOIBD F8130081-C0002BD F8130081-C0003BD F8130081-CO004BD F8130081-CO005BD F8130081-CO006BD F8130081-CO007BD F8130081-CO008BD F8130081-CO009BD F8130081-CO01OBD F8130081-Co011BD F8130081-CO012BD F8130081-CO013BD F8130081-CO014BD F8130081-CO015BD F8130081-CO016BD F8130081-CO017BD F8130081-Co018BD F8130081-CO019BD F8130081-CO02OBD F8130081 -C0021 BD F8130081-CO022BD F8130081-CO023BD F8130081-CO024BD F8130081 -CO025BD F8130081 -C0026BD F8130081-CO027BD F8130081-C0028BD F8130081-C0029BD F8130081-CO03OBD F8130081-CO031BD F8130081-CO032BD F8130081-C0033BD F8130081-C0034BD F8130081-C0035BD F8130081-C0036BD F8130081-C0037BD F8130081-COO38BD.F8130081-CO039BD Mean: Median: Standard Deviation:
Range: 1686 1966 2397 3911 6583 3807 2153 2391 1857 2537.1515 1302 1432 1452 1587 1235 1406 1421 1323 1328 1219 1261 1302 1515 1416 1286 1416 1307 1344 1079 1214 1146 1333 1442 1333 1416 1369 1629.1100 1754 1416 1014 1079-6583 Page 5 of 9 aFSS Summary Report F8130081 Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpmll00 cm 2)F8130081CO001SM F8130081 C0002SM F8130081 C0003SM F8130081 C0004SM F81 30081 C0005SM F8130081 C0006SM F8130081CO007SM F8130081 C0008SM F8130081 C0009SM F8130081Co010SM F8130081CO011SM F8130081CO012SM F8130081Co013SM F8130081CO014SM F8130081CO015SM F8130081CO016SM F8130081CO017SM F8130081Co018SM F8130081Co019SM F8130081 C0020SM F8130081C0021SM F8130081CO022SM F8130081 C0023SM F8130081 C0024SM F8130081CO025SM F8130081 C0026SM F8130081 C0027SM F8130081 C0028SM F8130081 C0029SM F8130081CO030SM F8130081C0031SM F8130081 C0032SM F8130081 C0033SM F8130081 C0034SM F8130081 C0035SM F8130081 C0036SM F8130081CO037SM F8130081 C0038SM F8130081 C0039SM.Mean: Median: Standard Deviation:
Range: 5.51 13.26 1.64 2.93-2.24-0.95-0.95 1.64-2.24 1.64 0.34-2.24 5.51 0.34-2.24-2.24-2.24 0.34 0.34 8.09-0.95-0.95 9.38-0.95 2.93-2.24-3.53 2.93-3.53 4.22 0.34-2.24 2.93 8.09-2.24 2.93 4.22-0.95 0.34 1.21 0.34 3.84-3.53 to 13.26 Page 6 of 9 FSS Summary Report F8130081 Survey Unit Data Assessment:
The survey design~required 39 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 7 of 9 FSS Summary Report F8130081 Table 4. Data Assessment Results f Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2): N/A Ambient Background Used (dpm/1O0 cm 2): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 39 Median (dpm/lOO cm 2): 1416 Mean (dpm/100 cm 2): 1754 Direct Measurement Standard Deviation 1014 (dpm/100 cm 2): Total Standard Deviation (dpm/100 cm 2): 1014 Based on samples and backgrounds.
Maximum (dpm/100 cm 2): 6583 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 39 S+ Value: 39 Critical Value: 25 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 F8130081 Survey Unit Investigations and Results: Five (5) investigations (scan grids C0036, 37, 112, and junctures C0047 and 063) 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 reported demonstrating compliance with the specified acceptance criteria.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 F8130081 meets the release criteria of lOCFR20.1402.
Page 9 of 9 FSS Summary Report F8130081 Attachment 1 Maps June 12, 2008 Survey Unit F8130081 (D 0 KEY PLAN EL. -47'REFLECTED CEIUNG PLAN REFLECTED CEILiNG PLAN FL. U/S EL. -22' EL. U/S EL. -39'FLOOR PLAN FLOOR PLAN EL -47" EL. -29'-6" SCALE MIETERS O0 00 C-)00 SACRAMENTO MUNICIPAL UTILITY DISTRICT AUXILIARY BUILDING -47'-0" WEST AB STAIRWELL PLAN & CEILING GEN ARRGMNT SURFACE AREA ESTIMATE F81 30081 -M1 FILE' 81.30000.1 S'-IELT I of 3 RC' RAYMOND
(,'D-171-5227 5220-18 SO m CONCRETE NORTH WALLýCEAL E M-ETE;F)0 SMUD SACRAM~ENTO MUNICIPAL UTILITY DISTRICT AUXILIARY BUILDING -47'-0" WEST AB STAIRWELL WALL ELEVATIONS GEN ARRGMNT SURFACE AREA ESTIMATE F8130081-M1 FILE:8 3OO0.01 SHEET 2 &f , RC RAYMOND 0(0 SOUTH WALL WEST WALL 00 WCALE mEiEtis SACRAMENTO MUNCPAL UTILTY DITRC AUXILIARY BUILDING -47'-0" WEST AB STAIRWELL WALL ELEVATIONS GEN ARRGMNT SURFACE AREA ESTIMATE F81 30081-M1 FiM.E:813000.01 SHEET 3 of PC. PAYLAnOt,1")
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KEY PLAN EL. -47'REFLECTED CEIUNG PLAN REFLECTED CEILING PLAN EL. US EL. -22' EL, U/S EL. -39" FLOOR PLAN FLOOR PLAN EL -4.7" -9 SCALE MIE:TEP.S ( DN 00 0 0 00 SACRAM~ENTO.
MUNICIPAL UTiL[Th' DISTRICT SURVEY LOCATION MAP WEST AB STAIR PLAN & CEILING PENETRATION SCANS F8130081-M5 v3ncvn_,i SHEE-iI of .3 pc"' IcAY 11l r i'm 1'1300001 SHELI 1, of 3 RC RAY
-P-02 P-03 NORTH WALL EAST WALL It 00 00 SCALE METERS Atk5MUR-SACRAMAENTO MUNICIPAL UTILITY DI&TPICT RI F> ~I SURVEY LOCATION MAP WEST AB STAIR PLAN & CEILING PENETRATION SCANS F8130081-M5 1.3noool SHEET 2 of 3 Rc pA'FILE: 81300001 .SHEET 2 of 3 RC MOND
-Q O0 00 00 P-09 SOUTH WALL 0 1 2 3 SACPA1WE'fO MUNICIPAL UTILITY VISTRICT SCALE METERS SURVEY LOCATION MAP WEST AB STAIR PLAN & CEILING PENETRATION SCANS F8130081 -M5 13000.01 SHEET 3 of 3 RC RA'ý Attachment 2 Instrumentation June 12, 2008 Survey Unit F8130081 Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpmll00 cm 2) (dpm/100 cm 2)930A 1680A M2350; 180733 43-98B; 148638 1400B 25208 M2350; 180733 43-94; 148620 5 9 0 c 1030c M2350; 175834 43-68B; 190482 M2350; 193700 43-68B; 190294 433 D 1033 D"920 E 2195 E M2350; 149789 43-68B; 161397 M2350; 149794 43-68/5B; 149103 M2350;, 149789 43-116-1B; 256006 M2350; 149794 43-116-1B; 256005 4 9 6 F 3 D M2350; 193700 43-116-1B; 216072 M2350; 175834 43-116-1B; 190642 Tennelec; 0401171 N/A 6 dpm a, 12 dpm 3 N/A A Penetration
-3" -concrete B Penetration
-4" -concrete c Penetration
-1" -concrete D Surface concrete E Surface -concrete -1 paint'layer F Juncture -concrete Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm 2)Investigation Criteria -Direct 43000 A Investigation Criteria -Scan 43000 A DCGLw 43000 DCGLEMC 154800 A Investigation Level set conservatively at DCGLw within survey instruction package.Page 2 of 2 Att. 2 Instrumentation F8130081 Attachment 3 Investigation June 12, 2008 Survey Unit F8130081 Table 3-1 Survey Unit Investigation
- InvesInvestigationm Investigation
'Initial Value Investigation Elevated Area Investigation DCGLemc Grid Lev (cpm) 'CMi Result Area /ml Ft DCGLemc Result Unity em (cpm) A (m acor (dpm/lOOcm
- 2) Fraction C0036BS 2748' 3514 3514 .13 105.8 4551135 54779 0.012 C0037BS 5840 261i9 3274** NA NA NA 24018 NA C0047JS 1990 B 2785 1274** NA NA NA 27528 NA C0063JS 4260 173592c T 494 NA NA NA 4980 NA CO 112BS 5840 8168 3420** NA NA NA 25089 NA Comments: A Adjusted for single layer paint.B Surface Scan Investigation Level use due to survey techniques and geometry of remediated juncture c Survey instrument spike -could not be reproduced in field or in lab. Resurveyed juncture 10/15/2008
- Post remediation results Survey Unit Remainder Page 2 of 2 Att. 3 Investigation F8130081 Attachment 4 Data Assessment June 12, 2008 Survey Unit F8130081 00 Cd)00 F8130081 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpmt1 00cm 2 1.4., a, 7,000 6,000 5,000 4,000 3,000 2,000 1,000 0 1416 0 20 40 60.Percentile 80 100 I
- Direct Measurements (dpm/l00cm2) -median ---75th Percentile
--- -50th Percentile I
ý4 TJQ 00C0 20 F8130081 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpml100cml 7000 R E E 6000-5000 4000 3000-2000-1000 0--1000--2000 O o 0 o 0 0 0_0___a." --0 0 0o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 M w a w a a
- a ---In M w M Ow a ,, ,, , 4w w 479C 1754-1 28E QOCCOCCOCQQOOOQOOOQQOOCOOOOOCOCCQQQOCOCO 00000000=0000000000 80000 UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU Measurement Locations I o Gross Activity -Average --"+3StDev" --M3StDev"i (r CD 0 IJ-00 Cj2 C0 00 F8130081 Gross Activity Frequency Plot DCGL = 43000 dpm/1 00cm 2 C 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0-t-0)N-0 Bins -Upper End Value (dpm/1 00cm2)