l 71147a lead fss engineer

Rancho Seco

Final Status Survey Summary Report

June 10, 2008

AB -20' Corridor room 10 upper walls and ceiling

Survey Unit F8130102

Prepared By: Dan A. Tallman z-ý." Date: June 10, 2008

FSS Engineer

Reviewed By:IŽ•Ž L" ate: 71147a

Lead FSS Engineer

Approved By: Date: 7,••3Dismantlement Superintendent, Radiological

FINAL STATUS SURVEY SUMMARY REPORT

Survey Unit:F8130102, AB -20' Corridor room 10 upper walls and ceiling

Survey Unit Description:Operating History: The Auxiliary Building is a reinforced concrete structure thatcontained the RadWaste processing and supporting systems. The building contained sixmain elevations. Residual radioactive material was known to be present on all levels ofthe interior of the building. Operating records and the HSA document several eventswith the potential for a release of radioactivity inside this structure.

Site Characterization: Direct measurements were made of each of the interior elevationsurfaces as well as the exterior surfaces of the structure. These measurements confirmedthe presence of plant-derived radionuclides. Direct measurements on the -20' elevationshowed a mean gross activity level of 247,831 dpm/100 cm2 and a maximum value of10,080,000 dpm/100 cm 2, Based on the classification procedure (DSIP-0020) and levelsof gross activity reported, the upper walls and ceiling of room 10 in the interior of theauxiliary building was determined to be a Class 2 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 patternand 167 m2 were scanned for approximately 70% coverage. Samples of removablecontamination were collected at each direct measurement location. The instrumentationused for the survey along with the MDC values are listed in Tables 2-1 and 2-2 inAttachment 2.

of 8 FSS Summary Report F8130102

Table 1. Survey Unit Design Parameters

Survey ,Design Value CommentParameter

Survey Area: F8 f3

Survey Unit:Class:

SU Area (m2):Evaluator:

DCGL (dpm/100 cm2):

Area Factor:Design DCGLemc

(dpm/100 cm 2):

LBGR (dpm/100 cm2):

Design Sigma (dpm/100 cm2):

Type I Error:Type II Error:

Predominant Nuclide:Sample Area (m2):

Scan Area (M2 ):

Scan Coverage (%):Zj." :ZI-0 :

Sign P:Calculated Relative Shift:

Relative Shift Used:

N-Value:Design N-Value + 20%:Design Min Samples N:

Grid Spacine L:

01022

239.4D.A.Tallman

43000N/AN/A

2150012035

0.050.05

Cs-13714

16770%

1.6451.645

0.9554351.71.7

1417173.7

AB -20' Corridor room 10upper walls and ceiling

Structure SurfaceLTP Table 5-4

Gross Activity DCGLClass 2Class 2

Default = 50% DCGL

Class 2

Class 2

Uses 3.0 if Relative Shift is>3

NUREG-1575 Table 5-5Class 2Class 2


Survey Results:A total of 17 direct measurements were made in F8130102. The results including mean,median, standard deviation and range are shown in Table 2. All direct measurementswere less than the DCGL. None of the scan measurements indicated areas of elevatedactivity. Scan activity ranged from 2067 to 31442 dpm/100 cm2 , based on a surveyorefficiency of 0.5 and no background subtracted. ISOCS scan activity on the ceiling allless than MDA for both Cs-137 and Co-60. Samples for removable surface activity wereall less than 10% of the DCGL as shown in Table 3. Removable surface activity sampleswere counted for alpha activity and none was detected at the MDC shown in Table 2-1 ofAttachment 2.

Table 2. Direct Measurement Results

Measurement ID Gross Activity(dpm/100 cm

F8130102-CO001BD 1696F8130102-CO002BD 1717F8130102-CO003BD 1644F8130102-CO004BD 1764F8130102-CO005BD 1810F8130102-CO006BD 2080F8130102-CO007BD 1421F8130102-CO008BD 1567F8130102-CO009BD 1748F8130102-CO01OBD 1426F8130102-CO011BD 1572F8130102-CO01 2BD 1758F8130102-CO013BD 1624F8130102-CO014BD 1411F8130102-CO015BD 1556F8130102-CO016BD 1655F8130102-CO017BD 1152

Mean: 1624Median: 1644

Standard Deviation: 205Rannge: 1152-2080


Table 3. Removable Surface Activity Results

Measurement ID Surface Beta Activity(dpm/1 0O, cm 2 )

F8130102CO010SMF8130102C0001SMF8130102C0002SMF8130102C0003SMF8130102CO004SMF8130102C0005SMF8130102C0006SMF8130102C0007SMF8130102CO008SMF8130102CO009SMF8130102C0010SMF8130102CO011SMF8130102C0012SMF8130102C0013SMF8130102CO014SMF8130102COOI5SMF8130102C0016SMF8130102C0017SM

Mean:Median:

Standard Deviation:Range:

1.64-2.244.22

-3.53-3.53-2.241.64

-2.24-2.242.93

-2.242.93

26.1727.46

0.34-2.249.380.343.140.349.22

-3.53 to 27.46


Survey Unit Data Assessment:The survey design required 17 direct measurements for the Sign Test. The critical valueand the results of the Sign Test are presented in Table 4. The sample mean and medianvalues were less than the DCGL. The sample standard deviation was less than the designstandard deviation so no additional samples were required.


Table 4. Data Assessment Results

Survey Results Parameter Value Comment

Material Background Used (dpmIO00 cm2): N/A

Ambient Background Used (dpm/100 cm2): N/A Average Ambient BKG = 0Actual Direct Measurements (N): .17

Median (dpm/100 cm2): 1644Mean (dpm/100 cm

2): 1624

Direct Measurement Standard Deviation 205(dpm/100 cm2):

Total Standard Deviation (dpm/100 cm 2): 205 Based on samples andbackgrounds.

Maximum (dpm/100 cm2): 2080

Material Type: N/A Background Subtract NotApplied

Sign Test Final N Value: 17S+ Value: 17

Critical Value: 12Sufficient Samples Collected: Yes

Maximum Value < DCGL: YesMedian Value < DCGL: Yes

Mean Value < DCGL: YesMaximum Value < DCGLemc: N/A Class 2

Total Standard Deviation <= Sigma: YesPass the Sign Test? Yes

Reject the Null Hypothesis? YesDoes the Survey Unit Pass All Criteria? Yes


Survey Unit Investigations and Results:No investigations were required for either direct or scan measurements and noinvestigation results are reported.

ALARA Statement:As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit isless than the DCGL (i.e. the survey unit average activity is less than the DCGL), theALARA 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 areconsistent with that classification. The variability of the survey results was less than thecharacterization data used for survey design.

Conclusion:The FSS of this survey unit was properly designed as a Class 2 survey based on Table 5-4of the LTP not withstanding the design sigma value usage described on page two. Therequired number of direct measurements was made and the scan coverage met therequirement of Table 5-6 of the LTP. No direct measurements exceeded the DCGL of43000 dpm!100 cm2 and none of the removable surface activity measurements exceeded10% of the DCGL. No investigations were required.

The direct measurement data support rejection of the null hypothesis, providing highconfidence that the survey unit satisfied the release criteria and that the data qualityobjectives were met.

It is concluded that survey unit F8130102 meets the release criteria of 1 OCFR20.1402.


Attachment I

Maps

June 10, 2008


CrD

NHom Wanl Eam Wam

rF ' do oilStalm

Und&~do oilStaim-

SoothWafl Wea Wanl

ii Ii

{-10' Floow N

General Surface Area Estimates

- -I I

.1Ceiling-Walls-StairsFloor-

53.8 n 2

172.7 m2

12.9 m2

0.0 m2

Total - 239.4 m 2

ýrI00 Ref•l•d Cerg

Scale Feet

3" = 1'AUXILIARY BUILDING EL. -20 ROOM 10

AND STAIRWELL 56SURFACE AREA ESTIMATE

F8130102-MiScale Meters

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LOOSE SURFACE MEASUREMENT POINTSF81 30102-M2

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Scale Meters

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FILE 81300.0"2a SHT 2 OF 3. T C HILLFEE 81300.02e SHT2OF3. TCHILL

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Scale Meters

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Scale Meters

0 1 2 3

O*SMUDSACRAMENTO MUNICIPALUTILITY DISTRICT

AUXILIARY BUILDING EL.. -20 ROOM 10-AND STAIRWELL 56 PENETRATION

BETA SCAN MEASUREMENT LOCATIONSF8130102-M5

FILE 81300.028 SHT1 OF2 T C HILL

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Scale Meters

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ujScale Feet81" = 1,-0"

Scale Meters

0 1 2 3

*SMUDSACRAMENTO MUNICIPALUTILITY DISTRICT

AUXILIARY BUILDING EL. -20 ROOM 10AND STAIRWELL 56

PENETRATION BETA SCANSF81 301 02-M51

T(C- HII I_______________________________________________ ______________________T C HILLu.U

Attachment 2

Instrumentation

June 10, 2008


Table 2-1. Survey Unit Instrumentation

Instrument Detector MDC Static MDC ScanModel; Serial No. Model; Serial No. (dpmll00 cm 2 ) (dpm/100 cm 2 )

M2350; 193700 43-68B; 190294 433 1033

M2350; 203481 43-68B; 148629 433 1033

M2350; 193700 43-116-IB; 216072 491' 739'

Tennelec; 0401171 N/A 6 dpm a, 12 dpm3 N/A

A Juncture - concrete

Instrument Detector MDC ScanModel; Serial No. Model; Serial No. (dpm/100 cm 2 )

ISOCS 19839201 1160 - Cs137882 - Co60

3920_2mconcrete geometry 12 m2 FOV

Table 2-2. Investigation Criteria and DCGL

ValueParameter (dpm/100 cm 2)

Investigation Criteria - Direct 43000

Investigation Criteria - Scan 43000

DCGLW 43000

DCGLEMC N/A

Page 2 of 2 Ant. 2 Instrumentation F8130102

Attachment 3

Investigation

June 10, 2008


. (none required)

Attachment 4

Data Assessment

June 10, 2008


00

C#2

Il

•F8130102 Gross Activity Sample Results Quantile PlotDCGL = 43000 dpm/1 00cm2

2,500

2,000

4-

1,500

1,000

1644

ntll

500

0

0 20 40 60 80 104

Percentile-Direct Measurements (dpm/1l00cm2) - median - - -75th Percentile . - 50th Perce

0 F8130102 Gross Activity Sample Results Scatter PlotDCGL = 43000 dpm/100cm"

2500

E 2000•1500-

500

0

0

0. 0 0 0 0 0

0 0

0

2238

1 1024

- t-- - - a -- - -. a 1 1010

i i i i i i i i i i i i i i i i

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Measurement Locations00

0

I0 o Gross Activity - Average - - "+3StDev" - - "-3SIDev

(D

CD

En

00

w

F81 30102 Gross Activity Frequency PlotDCGL = 43000 dprn/ 00cm2

L.LLCj-

8

7

6

5

4

3

1-

0 -

Bins - Upper End Value (dpm/1 00cm2)

l 71147a lead fss engineer

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