ML090890534

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Final Status Survey Summary Report 10/15/08, T&R, AB, Nseb +40' Bridge, Survey Unit F8140003
ML090890534
Person / Time
Site: Rancho Seco
Issue date: 10/16/2008
From: Tallman D
Sacramento Municipal Utility District (SMUD)
To:
NRC/FSME
Shared Package
ML090830613 List: ... further results
References
DPG 09-097, F8140003
Download: ML090890534 (20)


Text

Rancho Seco Final Status Survey Summary Report October 15, 2008 T&R, AB, NSEB +40' Bridge Survey Unit F8140003 Prepared By: Dan k. Taliman 6Kýý,Ia Date: October 16, 2008 FSS Engi eer Reviewed By: Date: 131(9[

Lead FSS Engineer Approved By: Z7 (/17 _ Date: Z'_ Dismantlerrntý perintendent, Radiological

FINAL STATUS SURVEY

SUMMARY

REPORT Survey Unit:

F8140003, T&R, AB, NSEB +40' Bridge Survey Unit

Description:

Operating History: The Survey Unit consists of the access corridor between the Training and Records Building, Auxiliary Building, and Nuclear Service Electrical Building at the

+ 40' elevation. The floors, walls, and ceiling are included within this survey unit. This area is referred to as the "tunnel" in some drawings. During the survey of each interface with this interconnecting feature, no provision was made for survey of the tunnel.

Site Characterization: Direct measurements on the +40' elevation of the AB showed a mean gross activity level of 3,288 dpm/100 cm 2 and a maximum value of 24,781 dpm/100 cm2. Characterization surveys performed of the uncontrolled side of the AB 22 resulted in a mean gross activity of 1982 dpm/100 cm2 with a maximum of 2360 dpm/100 cm 2 and a standard deviation of 160.8 dpm/100 cm 2 . Direct measurements of the T&R building showed a mean gross activity level of 1,865 dpm/1 00 cm2 and a maximum value of 2,995 dpm/100 cm 2 . Direct measurements of the NSEB showed a mean gross activity level of 1,913 dpm/100 cm 2 and a maximum value of 2,669 dpmrn100 2

cm2.

Based on the classification procedure (DSIP-0020) and levels of gross activity reported in the region of the survey unit, the "tunnel" was determined to be Class3.

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 randomly determined and 60 m 2 were scanned for approximately 14%

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 7 FSS Summary Report F8140003

Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F814 T&R, AB, NSEB +40' Bridge Survey Unit: 0003 Structure Surface Class: 3 LTP Table 5-4 SU Area (m2): 431.4 Evaluator: D.A.Tallman DCGL (dpm/100 cm 2): 43000 Gross Activity DCGL Area Factor: N/A Class 3 Design DCGLemc N/A Class 3 (dpm/100 cm 2):

LBGR (dpm/100 cm 2): 21500 Default 50% DCGL Design Sigma (dpm/100 cm 2 ): 3627 Type I Error: 0.05 Type II Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m2): N/A Class 3 Scan Area (m 2): 60.8375 Scan Coverage (%): 14% Class 3 1.645 ZI-P*

1.645 Sign P: 0.99865 Calculated Relative Shift: 5.9 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 3 Grid Spacing L: N/A Class 3 Page 3 of 7 FSS Summary Report F8140003

Survey Results:

A total of 14 direct measurements were made in F8140003. 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 1731 to 3153 dpm/1 00 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/i00 cm)

F8140003-GO001 BD 1598 F8140003-GO002BD 1006 F8140003-GO003BD 939 F8140003-GO004BD 846 F8140003-GO005BD 1520 F8140003-GO006BD 1063 F8140003-GO007BD 980 F8140003-GO008BD 1063 F8140003-GO009BD 1535 F8140003-GO01OBD 877 F8140003-GO011BD 975 F8140003-GO012BD 887 F8140003-GO013BD 1401 F8140003-GO014BD 840 Mean: 1109 Median: 993 Standard Deviation: 277 Range: 840-1598 Page 4 of 7 FSS Summary Report F8140003

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

F8140003GOOOISM -2.24 F8140003G0002SM -4.82 F8140003G0003SM -3.53 F8140003G0004SM -2.24 F8140003G0005SM -2.24 F8140003G0006SM -2.24 F8140003G0007SM -4.82 F8140003G0008SM -3.53 F8140003G0009SM -3.53 F8140003G001 OSM -3.53 F8140003G0011SM -2.24 F8140003G001 2SM -4.82 F8140003G001 3SM -4.82 F8140003G0014SM -3.53 Mean: -3.44 Median: -3.53 Standard Deviation: 1.03 Ranqe: -4.82 to -2.24 Page 5 of 7 FSS Summary Report F8140003

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.

Table 4. Data Assessment Results Survey Results Parameter Value Comment 2

Material Background Used (dpm/100 cm ): N/A Ambient Background Used (dpm/100 cm 2): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 14 Median (dpm/100 cm2): 993 Mean (dpm/100 cm ):2 1109 Direct Measurement Standard Deviation 277 2

(dpm/100 cm ):

Total Standard Deviation (dpm/100 cm 2): 277 Based on samples and backgrounds.

Maximum (dpm/100 cm ): 2 1598 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 14 S+ Value: 14 Critical Value: 10 Sufficient Samples Collected: Yes MaximumValue < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: N/A Class 3 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 F8140003

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 3 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.

==

Conclusion:==

The FSS of this survey unit was properly designed as a Class 3 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 F8140003 meets the release criteria of 10CFR20.1402.

Page 7 of 7 FSS Summary Report F8140003

Attachment 1 Maps October 15, 2008 Survey Unit F8140003

UQ 0

PLAN VIEW FLOOR KEY PLAN 3h REFLECTED CEILING I East End Corridor Wall South Wall 1

Divider Wall East South West S

East End West End West End Vestibule Walls Vestibule Walls Corridor Wall

_ Looking I Looking Eat*Wes3t T11 00 Estlrn2tod Surfamsc~.as SCALE FEET AUX / T&R ! NSE BLDG BRIDGE Collm,~ 81,9m, C_= 1 FOOT 40'-0" ELEVATION wall. 260-9m:

FbOm 88.6 m SCALE METER GENERAL SURFACE AREA ESTIMATES SACRAMENTO MAUNICIPAL TOW~ 43! Aml 012345 UTILUTh' DLSTRICT F8140003-M1 flW~Z- ~ 1 4-flfWl3 n I PAC*r 11 PACE

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BETA DIRECT/LOOSE ACTIVITY LOCATIONS 4: ~=4'SACRAM/ENTO MUIIF4lllAL 234

  • F8140003-M2 I -0 1 Dw: e1.o00o03 1 PAGE 1 of 35 TC HILL 1 3 . 7 4 7 '2 13 Ir. ld i 17 ,A I -

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-4N BRIDGE PLAN VIEW FLOOR KEY PLAN J UII cj. u N..

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REFLECTED CEILING Irj 00 SCALE METER SMU/E c 4Mh-AUX / T&R / NSE BLDG BRIDGE 40'-0" ELEVATION BETA DIRECT/LOOSE ACTIVITY LOCATIONS MUNICIPA SACAMNT F8 140003-M2 0123 4 5 MG81400 ,CA31i P4L(F -1 OF 2ý TC HlII

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East End

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Eou~t South South Wall West Encd West nd East End Vestibule Wails Corridor Wad Vestibule Wals O0 00 AUX / T&R / NSE BLDG BRIDGE Uj 40'-0" ELEVATION SCALE METER BETA DIRECT/LOOSE ACTIVITY LOCATIONS SACRAM/ENTO MUu\ICIPA.

U*HIII tI F8140003-M2 0-1 2 3 4 5 Dwcr.,R1-0030 i I0 PACE 3 of 3 Tf, ;A4li

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  • West NorthI East HNorlh t E!d DEVELOPED NCTH WALL Corridor Wall Northi Eest South Wall Divider Wall L05t aoutn WestS East End st End West End Vestibule Wails Vestrb uie Wails Corridor Wall

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  • SMUD Al BETA SCAN LOCATIONS SACRAMENTO CMUNICIPAL -

012345 UiLiTY D0STP!CT F8140003-M3 SDWC:8140003.CI PACE i OF 1 TC HILL

Attachment 2 Instrumentation October 15, 2008 Survey Unit F8140003

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; 203486 43-68B; 190476 433 1033 M2350; 142499 43-37; 148502 N/A 616 Tennelec; 0401171 N/A ' 6 dpm a 12 dpm N/A Table 2-2. Investigation Criteria and DCGL Parameter Value Value cm 2 )

(dpm/100 c2 Investigation Criteria - Direct 21500 Investigation Criteria - Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8140003

Attachment 3 Investigation October 15, 2008 Survey Unit F8140003 (none required)

Page 1 of 1 Att. 3 Investigation F8140003

Attachment 4 Data Assessment October 15, 2008 Survey Unit F8140003

F8140003 Gross Activity Sample Results Quantile Plot 0D DCGL = 43000 dpm/1 00cm2 1,800 1,600 1,400 4U-1,200 1,000 In 800 CD 600 400 200 C)

.0 0 20 40 60 80 100 Percentile I

  • Direct Measurements (dpm/100crn2) - median - -75th Percentile ....- 50th Percentile

0 F8140003 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmll00cm=

2500 E 2000 - - -.... - - - - - - -. - - - - - - - - --

- -- --- -- -- 1 1940 0

5 o E 00 0

0 o

0 1109 1000 0 0 0 o

- - - o 278 0

~rj O 0 0 0 0 0 0 0 0 0 0- 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 Measurement Locations i o Gross Activity - Average - - "+3StDev" - - "-3StDev I 0

F8140003 Gross Activity Frequency Plot 2

DCGL = 43000 dpm/1 00cm 10 9-CD 8

7 6

07 0 5

4 3

2 1

0 O) 00 C0 Bins - Upper End Value (dpmi1 OOcm2)