ML17065A056

Rancho Seco Nuclear Generating Station - Final Status Survey Summary Report, December 28, 2016, Iosb DAW Staging Bay, Survey Unit F8300023

ML17065A056
Person / Time
Site:	Rancho Seco
Issue date:	01/24/2017
From:	Sacramento Municipal Utility District (SMUD)
To:	Office of Nuclear Material Safety and Safeguards
Shared Package
ML17065A032	List: ML17065A034 ML17065A035 ML17065A036 ML17065A037 ML17065A038 ML17065A040 ML17065A041 ML17065A046 ML17065A047 ML17065A048 ML17065A049 ML17065A051 ML17065A052 ML17065A053 ML17065A054 ML17065A055 ML17065A056 ML17065A057 ML17065A058 ML17065A059 ML17065A060 ML17065A061 ML17065A063 ML17065A064 ML17065A065 ML17065A066 ML17065A068 ML17065A069 ML17065A070 ML17065A071 ML17065A072
References
DPG 17-038
Download: ML17065A056 (17)

Text

Approved By: Rancho Seco Final Status Survey Summary Report December 28, 2016 IOSB DAW Staging Bay Survey Unit F8300023 FSS Engineer Manager, :Z:eco Assets FINAL ST A TUS SURVEY F8300023 Survey Unit: F8300023, Interim Onsite Storage Building (IOSB) DAW Staging Bay Survey Unit

Description:

Operating History: Designed primarily to store packaged radioactive waste containers safely, protected from the elements, and maintain radiological dose as low as reasonably achievable (ALAR.A.), the IOSB contained and possibly stored media of many types, including filters, resins, contaminated chemicals, DAW, activated reactor components, contaminated plant components and other contaminated items. Site Characterization:

Static measurements were made of the interior surfaces of the DAW Staging Bay to confirm the absence or presence of plant-derived radionuclides.

Static measurements showed a mean gross beta activity level of 2,637 dpm/100 cm 2 and a maximum value of 4,505 dpm/100 cm 2* The statistics of the DAW Staging bay results combines all lower walls, upper walls, floor, and ceiling data. Based upon the scanning results two elevated areas were identified on the floor. One of these areas exceeded the DCGLw but not the DCGLEMc. This area required remediation.

The other area did not exceed the DCGLw. The DAW Staging bay was divided into a small Class 1 Survey Unit, buffered by a Class 2 Survey Unit. The remainder of the Bay was designated as a Class 3 Survey Unit and is the subject of this report. 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. Static measurement locations were randomly determined and approximately 3% of the area scanned. The instrumentation used for the survey along with the MDC values are listed in Table 2-1 Attachment

2. FSS DAW Staging f 8300023 FINAL STATUS SURVEY F8300023 Table 1, Survey Unit Design Parameters

.. ' " *.*.

' *: .*r;'.: */::; *.* ... ' ,'. *.**.** ., . * *::¢o*mment5:

... * . ; :.*:" " -.-. . . " **. ' , ..... _. . **: Survey Packaqe: F830 DAW Staqinq Bay Survey Unit: 002 Class 3 SU Area (m 2) 248 Evaluator:

JR DCGLw: 43,000 Gross Activity DCGL Area Factor N/A Class 3 Desiqn DCGLemc (dpm/100cm 2): N/A Class 3 DCGLemc: N/A Class 3 LBGR: 21,500 Default = 50% DCGL Siqma: 598 Scopinq Survey Data Type I error: 0.05 Type II error: 0.05 Predominant Nuclide Cs-137 Area (m2) N/A Total Instrument' Efficiency:

0.132 From 10/26/16 Survey Total Area Scanned (m 2): 5.55 Scan Coveraqe (%) ..

Class 3 Choosing 'N/A' sets material Material Type: N/A background to "O" .\;,;,;:'

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.. F*. _ .....

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.. '* Z1-a: 1 .. 645 Z1-13: : 1.645 Sign p: 0.99865 Calculated Relative Shift: 35.9 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift >3 N-Value: 11 N-Value+20%:

14 2 FSS DAW Staging Bay f 8300023 FINAL STATUS SURVEY F8300023 Survey ,Results:

A total of 15 direct measurements were made in F8300023.

The results of the static measurements are shown in Table 2. All of the static measurements were Jess than the DCGL. None of the scan measurements indicated areas of elevated activity.

Swipe data did not indicate elevated activity levels above the MDA. Table 2, Static Measurement Results Number:*.**

• &ample#**

.... eeta (cpill) Beta (dPllJ)*

• 1 F8300023C00001 215 1,629 2 F8300023C00002 274 2,076 3 F8300023C00003 263 1,992 4 F8300023C00004 229 1,735 5 F8300023C00005 294 2,279 6 F8300023C00006 261 1,977 7 F8300023C00007 264 2,000 8 F8300023C00008 234 1,773 9 F8300023C00009 382 2,961 10 F8300023C00010 243 1,884 11 F8300023C00011 276 2,091 12 F8300023C00012 310 2,348 13 F8300023C00013 275 2,083 14 F8300023C00014 284 2,152 15 F8300023C00015 233 1,765 Table 3 contains the statistical summary of the static measurement data for the DAW Staging Bay. Table 3, Beta Summary Statistics Beta Static DAW Staging Bay Mean 2,050 Median 2,000 Standard Deviation 323 Minimum 1,629 Maximum 2,961 Count 15 3 FSS DAW Staging Bay f 8300023 FINAL STATUS SURVEY F8300023 Survey Unit Data Assessment:

The survey design required 14 static measurements for the Sign Test. A total of 15 static measurements were collected.

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. Table 4, Data Assessment Results Number of Samples: 15 Median: 2,000 Mean: 2,050 Static Data Standard Deviation:

323 Maximum: 2,961 Adjusted N Value: 14 S+ Value: 15 Critical Value: .10 Sufficient samples collected:

Pass Maximum value <DCGLw: Pass Median value <DCGLw: Pass Mean value <DCGLw: Pass Maximum value <DCGLemc:

N/A Sign test results:

• Pass The survey unit passes all conditions:

Pass 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, the ALARA criterion has been met. Changes in Initial Survey Unit Assumptions:

The survey unit was designed as a Class 3 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.

4 FSS DAW Staging Bay f 8300023 FINAL STATUS SURVEY F8300023

Conclusion:

The FSS of this survey unit was properly designed as a Class 3 survey based on the results of the scoping survey. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the LTP. All of the static measurements were less than the DCGL. No investigations were required.

The static 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 F8300023 meets the release criteria of 1 OCFR20.1402.

5 FSS DAW Staging Bay F8300023*

Attachment 1 Maps December 28, 2016 Survey Unit F8300023 F8300023C00011 6' J3 = 2,091dprn/100 cm 2 ) 6' F8300023C00013 . J3 ; 2,083 dpm/1 OQ crri 2 STAGING BAY tract No.: 4500091426 SMUD Locotlon:

P.ancho Seco ApproYOd by. Tcsk: Scnnin.a Survev Orowlng No.: rose SconinR SurvPV OescrlDUon:

DAW NORTH WALL Drown av. c Gr-"V AP!>"'vcl date: QC'ct. J Reese Dato: ll282016 Rav No.: Page 1 e F83Q0023C00006 J3 = 1 ,977 dpm/100 cm 2 F8300023C000106' 13 = 1,884 dpm/100 cm 2 F83o0023C00009

• Doc Tru Bay FB300023C000041B

• 13= 1,73.5 dpm/100 cm 2 J3 = 2,961 dpm/100 cm* f ..

\ .1 1 t** r":* r

'/ " I,_)\__, Door to DAV\ Bay '----'--ITTl F8300042 LhJJ F8300031 (inner) F8300023C00005 6' J3 = 2,279 dpm/100 cm 2 F8300023C00002ED J3 = 2,076 dpm/100 cm 2 Att. 1 Maps F8300023Cc:i0.0.14 13 = 2, 15.2 dpm/100 cm 2

• e F8300023C00007 6' J3 = 2,000 dpm/100 cm 2 F8300023C00003

e. J3 = 1,992 dpm/'100 cm 2 e F8300023C00012 J3 = 2,348 dpm/100 cm 2 FB300023C.00001 e J3 = 1 ,629 dpm/100 cm 2 F830Q023C000159 = 1,765 dpm/100 crh 2 F83Q0023C00008 e J3 = 1, 773 dpm/100 cm 2 0 10 20 5cale Infect F8300023

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--__ ----* . --

Attachment 2 Instrumentation December 28, 2016 Survey Unit F8300023 Table 2-1. Survey Unit Instrumentation

• • *.* 1)Pe,' Beta Static Measurement Beta Static Measurement Swipe Measurements

• Typ.e * -: . .

• . -. ' ;*. -,::* Ludlum Model 2350-1 Ludlum Model 44-116 B Detector Ludlum Model 2350-1 Ludlum Model 44-1 I 6 B Detector Ludlum Model 2929 Ludlum Model 44-10-1 IYJ.inimuri1 Actlvit);.

< Detectoi;. . . . Jf;fficier)cies Beta -492 dpm/l 00 cm 2 Beta -559 dpm/l 00 cm 2 Beta -73 dpm/100 cm 2 Beta-75 dpm/100 cm 2 12.9% 13.2% 43.4%

• . bu.e'nate 1 r .. *1:,.:/. **:*/ .,,o *: *. 317899/331973 2/10/17 317897/331972 2110117 182597 /188736 5/13/17

• Minimum detectable activities for the count rate instrumentation were calculated in accordance with NUREG-1507, "Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions" (U.S. NRC, 1997). b Detectors are required to be calibrated once every I 2 months. Calibration due date indicates the date by which the detector must be calibrated again. cm 2 = square centimeters cpm = counts per minute dpm =disintegrations per minute Page 1 Att 2 Instrumentation f 8300023 --------*-=-. .:-:.___ ...:.:....=*::::":*

Static Measurement MDA Variables Beta Survey Type PR331973 Detector Number 169 Background count rate (cpm) Count Time (min) 0 .12 9 Efficiency 100 Area of Detector ( cm 2) Constants 60 sec/min 2.54 cm/in Assumptions Background count time and sample count time are equivalent Calculate Static MDA Static MDA =3 + 4.65(Br

• t)0*5/t

• E

• A/100 (NUREG 1507) Where: Static MDA Page 2 Br t E A Background Countrate Count Time (min) Efficiency Area of detector (cm2) 492 dpm/100 cm 2 Att. 2 Instrumentation f 8300023 Static Measurement MDA Variables Beta Survey Type PR331972 Detector Number 232 Background count rate (cpm) Count Time (min) 0.132 Efficiency 100 Area of Detector (cm 2) Constants 60 sec/min 2.54 cm/in Assumptions Background count time and sample count time are equivalent Calculate Static MDA Static MDA =3 + 4.65(Br

• t)0*5/t

• E

• A/100 (NUREG 1507) Where: Static MDA Page 3 Br t E A Background Countrate Count Time (min) Efficiency Area of detector (cm 2) 559 dpm/100 cm 2 Att. 2 Instrumentation f 8300023 Attachment 3 Investigation December 28, 2016 Survey Unit F8300023 (none required)

Att. 3 Investigation f 8300023 Attachment 4 Data Assessment December 28, 2016 Survey Unit F8300023

' f 1 I I 17'.12 Pa ge 1 Histogram for Beta Static Activity (dpmf100 cm2) DAW Staging Bay Zl98 Att. 4 Data Assessment F8300023 A c t iv iy I Nt.rilerolVM.ie i MirWIUTI ""'"""' so 1S 1..628.79! Z$1.2* 322.8'1 157 Kt.to:;u lEIJ 0Me.v1 2.(U968 BM-0Lou9n' QMcweBN ___ I

' I. ! ., ' ;j ,, d I! ,. ' *1 I I :I ,I I d r:*** 12000 j I I l I ! J 2*00 1= ! I I 2000 1800 ""' *1.5 *1.0 Page 2 Q-Q Plot for Beta Static Activity (dpm/100 cm2) DAW Staging Bay -0.5 0.0 0.5 Thoorotical Quantiles (Standard Normal) Att. 4 Data Assessment 1.0 \.5 F8300023 Activl) tl*l5 Sd*322.8 Coudaticn.

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(, IOSB Final Status Survey 1.c;:2 I.Cl LCll LCG 1.(5 I fl CPM fldpm Date/Time of Courii s::implc Comments ..: -007. J c 00001 SM :;li.11!<:

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7,97.9 S/N: 18259'7 1rm., MD/\ 0.'13'1 44.5 /11.5 43-10-J S/N: 188136 I0/:!611<*

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1uf1 Page 3 Att. 4 Data Assessment F8300023