ML091000377

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Final Status Survey Summary Report 10/02/08, the Walls and Ceiling of the Ventilation Room 211 and the Duct Room 208, Survey Unit F8131372
ML091000377
Person / Time
Site: Rancho Seco
Issue date: 10/02/2008
From: Stein M
Sacramento Municipal Utility District (SMUD)
To:
NRC/FSME
Shared Package
ML090830613 List: ... further results
References
DPG 09-097, F8131372
Download: ML091000377 (26)
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Text

Rancho Seco Final Status Survey Summary Report October 2, 2008 The Walls and Ceiling of the Ventilation Room 211 and the Duct Room 208 Survey Unit F8131372 Prepared By: Date: /101O/4& 00 FSS Engineer Reviewed By." kw_

  • o Date: LO 4a Lead FSS Engineer Approved By: Date: __7___

Dismantlement Suerintendent, Radiological

FINAL STATUS SURVEY

SUMMARY

REPORT Survey Unit:

F8131372, The Walls and Ceiling of the Ventilation Room 211 and the Duct Room 208 Survey Unit

Description:

Operating History: The reinforced concrete structure 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. One report documented contamination of the auxiliary building roof. The roof was later replaced.

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 dpmr/100 cm 2. Direct measurements on the -29' elevation showed a mean gross activity level of 544,756 dpm/100 cm 2 and a maximum value of 11,370,000 dpm/100 cm 2 . Direct measurements on the -20' elevation showed a mean gross activity level of 247,831 dpm/100 cm2 and a maximum value of 10,080,000 dpm/100 cm 2. Direct measurements on the grade elevation showed a mean gross activity level of.373,758 dpm/100 cm 2 and a maximum value of 5,800,000 dpm/100 cm 2. Direct measurements on the +20' elevation showed a mean gross activity level of 85,408 dpm/100 cm 2 and a maximum value of 1,900,000 dpm/1 00 cm 2. Direct measurements on the +40' elevation showed a mean gross activity level of 3,288 dpm/l100 cm 2 and a maximum value of 24,781 dpm/100 cm 2. Direct measurements on the building exterior, including the mezzanine roof, showed a mean gross activity level of 1,897 dpm/100 cm 2 and a maximum value of 2,990 dpm/100 cm 2. (The roof had been replaced prior to the classification survey.) Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the interior of the auxiliary building was determined to be a Class 1, 2 area and the exterior was a Class 2,3. The walls and ceiling of the Ventilation Equipment Room 211 and the Duct Room 208 were determined to be a Class 2.

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 215 m2 were scanned for approximately 27% 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 F8131372

Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F813 The Walls and Ceiling of the Ventilation Room 211 and the Duct Room 208 Survey Unit: 1372 Structure Surface Class: 2 LTP Table 5-4 SU Area (m2): 811 Evaluator: Michael Stein DCGL (dpm/100 cm 2): 43000 Gross Activity DCGL Area Factor: N/A Class 2 Design DCGLemc N/A Class 2 (dpm/ 100 cm 2);

LBGR (dpm/100 cm 2): 21500 Default 50% DCGL Design Sigma (dpm/100 cm 2 ): 5461 Type I Error: 0.05 Type II Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m2): 57.9 Class 2 2

Scan Area (m ) 215 Scan Coverage (%): 27% Class 2 Zl-,, : 1.645 1.645 Sign P: 0.99865 Calculated Relative Shift: 3.9 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 Spacing L: I _ _ _ _ _ _ __ _ _ _ _ _ _

7.6 Class 2 Page 3 of 8 FSS Summary Report F8131372

Survey Results:

A total of 14 direct measurements were made in F8131372. 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 2,201 to 6,672 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 Activity (dpm/100 cm )

F8131372-CO001 BD 1354 F8131372-CO002BD 1691 F8131372-CO003BD 1795 F8131372-CO004BD 1769 F831 372-COOO5BD 1758 F8131372-CO006BD 1359 F8131372-CO007BD 1489 F8131372-CO008BD 1572 F8131372-CO009BD 1686 F8131372-CO01 OBD 1634 F8131372-CO01 I BD 1235 F8131372-CO012BD 1852 F8131372-CO01 3BD 1613 F8131372-CO014BD 1639 Mean: 1603 Median: 1637 Standard Deviation: 184 Range: 1235- 1852 Page 4 of 8 FSS Summary Report F8131372

Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity I(dpm/100 cm 2)

F8131372C0001 SM 2.29 F8131372C0002SM 1 F8131372C0003SM 1 F8131372C0004SM 1 F8131372C0005SM -0.29 F8131372C0006SM -1.58 F8131372C0007SM 24.24 F8131372C0008SM 2.29 F8131372C0009SM 2.29 F8131372C0010SM 1 F8131372C0011SM -0.29 F8131372C0012SM 2.29 F8131372C0013SM 7.46 F8131372C0014SM -1.58 Mean: 2.94 Median: 1 Standard Deviation: 6.52 Ranue: -1.58 to 24.24 Page 5 of 8 FSS Summary Report F8131372

Survey Unit Data Assessment:

The survey design required 14 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 F8131372

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): 14 Median (dpm/100 cm 2): 1637 Mean (dpm/100 cm 2): 1603 Direct Measurement Standard Deviation 184 (dpm/100 cm 2):

Total Standard Deviation (dpm/100 2 cm ): 184 Based on samples and backgrounds.

Maximum (dpm/O00 cm 2): 1852 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 14 S+ Value: 14 Critical Value: 10 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 I Page 7 of 8 P FSS Summary Report F8131372

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 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 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 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 F8131372 meets the release criteria of 10CFR20.1402.

Page 8 of 8 FSS Summary Report F8131372

Attachment 1 Maps October 2, 2008 Survey Unit F8131372

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Scale Meter~s 1 2 3 S SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT MEASUREMENT LOCATIONS F8131372-Mi

_________________________________ I _______________ FILE:813000.04e SHEET 1IOF3 T C HILL

0" East South East Room 211 Developed East Wall 00 Ua Scale Feet L" = 13,-0" 32 -" AUXILIARY BUILDING EL. 20' ROOM 208 & 211 w*

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Scale. Meter-SSMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT MEASUREMENT LOCATIONS F8131372-Mi 0 1 2 3 4 5 FILE: 813000.04e SHEET 2 of 3 TCHI

44 134 N E S W N E S W Col. "N/ 8.T' Col. "PT9:1" Room 211 Developed West Wall Room 211 Columns w N E S W NW Wall East Wall South Wall Col. "P / 9.7" Col. "N./ 9.7" Room 208 Walls

ýrI 00 Lo3 Scale Feet I2 = 11-0" AUXILIARY BUILDING BETAEL. 20' ROOM 208 & 211 0 1 Scale. Meters 2 3 4 5 S SMUDPACRAMENTO MUNICIPAL UTILITY DISTRIC-T H PAl~.ffl~flfIn FI F8131372-Ml SCAN MEASUREMENT LOCATIONS SHFET 3 nf 3 TC VII lII LE: 813000 04e SHEET 3 3 TCHILL

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Scale Meters 0 i 3 SSMUD SACRlAMEN4TO MUN4ICIPAL UTILITY DISTRICT BETA DIRECT/ LOOSE SURFACE MEASUREMENT LOCATIONS F8131372-M2 FU F-R 1.flfl00 d SH~ErT2OF4 TC:H/ ILL FILE: 811(100 04e SHEET 2 OF4 TCHtLL

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00 Room-211 Developed West Wall NW Wall East Wall South Wall West Wal Room 208 Walls

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BETA DIRECT/ LOOSE SURFACE Scale Meters MEASUREMENT LOCATIONS SACRAMENTO MUNICJPAL 012345 UfiITrY DiSTRIGT F8131372-M2 FIt F *R 1.,(3('l lAn SHEET 4OF 4 TCH-IIlL FLE, 813000 04e SHEET 4 Of 4 TCHLL

0 KEY PLAN IrJ 00 Estimated Surface Area Ceiling 366.5 m2 Scale Feet AUXILIARY BUILDING EL. 20' ROOM 208 & 211 2

Walls 443.7 m ESTIMATED CEILING SURFACE AREA Total 810.22 S1ale4 Meter *SMUD SACRAMENTO MUNICIPAL AND, PENETRATIONS 0 1 2 34 5 UTILITY DISTRICT F8131372-M3 FILE: 813000.04e 'SHEET 1 of3 T C HILL

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P32 P31 P30 P29 P28 P21, P26 P25 O-4 P17 P18 P19 P20 P21 P22 P23 P24 P16 P15 P14 P13 P12 P11l P o0 .

1P33 P01 P02 P03 P04 P05 POE P07 P08 i - P35* P36 Room 211 RX Wall East South East Room 211 Developed East Wall OT1 00 Scale Feet AUXILIARY BUILDING EL. 20' ROOM 208 & 211

  • MD P2 = 1'-0"

(-4 ESTIMATED WALL SURFACE AREA Scale Meters AND PENETRATIONS SACRAMNE'TO MUNUCOPAL UTIUTY DISTR&C F8131372-M3 0 1 2 3 45 FILE: 81-4Of0.04e SHEET 2 of3 T C HILL

F-0 N E S W W Col. "N/ 8.7" Col. TP 19.1" Room 211 Developed WestWall (9.3) Room 211 Columns

  • 6 cj~ .. P46 NWlE NW Wall East Wall South Wall West Wal) Col. "P 1 9.7' UH WN LiLiLi E S Col. N1/9.7" W

Room 208 Walls 00 Scale Feet cc 32 AUXILIARY BUILDING EL. 20' ROOM 208 & 211 Scale Meters ESTIMATED, WALL SURFACE AREA AND PENETRATIONS SACRAMENTO MU'!CIPAL 0 1 2 3 4 5 UTILITY DISTRIGT F8131372-M3 FILE: 813000.04e SHEET 3 of3 T C HILL

Attachment 2 Instrumentation October 2, 2008 Survey Unit F8131372

Table 2-1. Survey Unit Instrumentation Instrument Model; Serial No.

M2350; 193700 Detector Model; Serial No.43-68B; 190294 MDC Static (dpm/100 cm2 )

433 T MDC Scan (dpm/100 cm 2 )

1033 M2350; 203486 43-68B; 161400 433 1033 M2350; 175834 43-68B; 148634 433 1033 M2350; 193700 43-116-1B; 216072 796 3258 4.9 dpm c, Tennelec; 0401171 N/A N/A 8:2 dpm P3 The scan and static MDC's provided represent the most conservative MDC values for the survey conducted.

Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm 2 )

Valuec2 Investigation Criteria - Direct 43000 Investigation Criteria - Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8131372

Attachment 3 Investigation October 2, 2008 Survey Unit F8131372 (none required)

Attachment 4 Data Assessment October 2, 2008 Survey Unit F8131372

CF8131372 Gross Activity Sample Results Quantile Plot 0 DCGL = 43000 dpm/1 00cm2 2,000 - 7, 1,800...................

1,600 2010

..... 637

<* .* 800 [

0 20 40 60 so 100 Percentile

-

  • Direct Measurements (dpm/100cm2) -median -75th Percentile 50th Percentile

0D F8131372 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmIl00cm=

2500

- - -- -- a - - - - a - a- - - - 2154

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0 2000

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o C 11603 1500 0 00 C.

1000 - - a a a - - - a a - a a- - - - a a a - - ----- a a- 11052

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~r1 uJ C o C C C2 0 a aC3 a 0 Ck C C C a a a asr a Lat o C Measurement Locations 00 o Gross Activity - Average - - "+3StDev" - - -3StDev" U)

F8131372 Gross Activity Frequency Plot 0

DCGL = 43000 dpm/1 00cm2 4-3 0

2 Ln2 0-c'N-~J .0 LO (Y~)

1-00 Bins - Upper Fnd Value (dpm/100cm2)

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