ML17065A068

Rancho Seco Nuclear Generating Station - Final Status Survey Summary Report, January 30, 2017, Iosb Outside Area Class 2, Survey Unit F8300142

ML17065A068
Person / Time
Site:	Rancho Seco
Issue date:	01/30/2017
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: ML17065A068 (14)

Text

Rancho Seco Final Status Survey Summary Report January 30, 2017 IOSB Outside Area Class 2 Survey Unit F8300142 FSS Engineer fl Approved By: .er'""= , Date: :fe-3 /rl .. Manager, Rancho Seco Assets FINAL STATUS SURVEY F8300142 Survey Unit: F8300142, Interim Onsite Storage Building (IOSB) Outside Area Class 2 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 (ALARA),

the IOSB possibly stored media of many types, including

filters, resins, contaminated chemicals, DAW, activated reactor components, contaminated plant components and other contaminated items. The outside asphalt area at times held waste ready to ship in storage containers and a respiratory cleaning facility.

Site Characterization:

Based upon the scanning results of the outside asphalt area an elevated area was identified on the asphalt next to the IOSB. Certain spots in the area exceeded the DCGLw but not the DCGLEMC*

The area required remediation.

The Outside area was divided into a small Class I Survey Unit, buffered by a Class 2 Survey Unit. The remainder of the outside asphalt was designated as a Class 3 Survey Unit and is the subject of a separate report. Survey Unit Design Information:

In accordance with MARSSIM Section 4.6, special considerations may be necessary for survey units with structure surface areas less than IO m2 or land areas Jess than 100 m2* In this case, the number of data points obtained from the statistical tests is unnecessarily large and not appropriate for smaller survey unit areas. The data generated from these smaller survey units should be obtained based on judgment, rather than on systematic or random design, and compared individually to the DCGLs. This survey unit meets this criterion as the size is less than ten square meters (1.85 m2). 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 determined by professional judgment in accordance with MARSSIM guidance and approximately l 00% of the area scanned.

The instrumentation used for the survey along with the MDC values are listed in Table 2-1 Attachment

2. FSS Loading Dock Class 2 F8300142

\,

FINAL STATUS SURVEY F8300142 Table 1, Survey Unit Design Parameters

• ., > ., , ,

• *.* ,f* r*. .* . , " ,. . -. " .. comnl'ents

::.* . . .. ., ' Survey Packaqe:

F830 Outside Asphalt Class 2 Survey Unit: 014 Class 2 SU Area (m2) 1.85 Evaluator:

JR DCGLw: 43,000 Gross Activity DCGL Area Factor NA Class 2 Desiqn DCGLemc (dpm/100cm 2): NA Class 2 DCGLemc:

NA Class 2 LBGR: 21,500 Default = 50% DCGL Sigma: 513 Type I error: 0.05 Type II error: 0.05 Predominant Nuclide Cs-137 Sample Area (m2) NIA Total Instrument Efficiency:

0.132 Total Area Scanned (m2): 1.85 Scan Coveraqe

(%)

Class 2 Choosing

'N/A' sets material Material Type: N/A background to "O" .**>:.::::.>:,

.*. "> * ..

.... :: * ... .;;'//.:

-*,, *

• :'.. > X' , < .*. ,.*, .,;,. Z1-a: 1.645 Z1-a: 1.645 Sign p: 0.99865 Calculated Relative Shift: 41.9 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift >3 Values selected based upon N-Value:

10 Judgement Values selected based upon N-Value+20%:

NA Judgement Survey Results:

A total of IO direct measurements were made in F8300142.

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

2 FSS Outside Area Class 2 F8300142 FINAL STATUS SURVEY F8300142 Table 2, Static Measurement Results ,.,, .. Numbef . .

.. Beta.:(cpm):

Beta (d.P.m),

. . . .. ' . ,.* .. ' .. ,, ' . . *\ ... ... 1 F8300142A00001 266 2,015 2 F8300142A00002 316 2,394 3 F8300142A00003 345 2,614 4 F8300142A00004 340 2,576 5 F8300142A00005 320 2,424 6 F8300142A00006 373 2,826 7 F8300142A00007

. 350 2,652 8 F8300142A00008 369 2,795 9 F8300142A00009 373 2,826 10 F8300142A00010 343 2,598 Table 3 contains the statistical summary of the static measurement data for the Outside Area Class 2. Table 3, Beta Summary Statistics Beta Static Outside Asphalt Class 2 Mean Median Standard Deviation Minimum Maximum Count Survey Unit Data Assessment:

2,572 2,606 247 2,015 2,826 10 The survey design was based upon professional judgement and resulted in I 0 static measurements.

Following the guidance in MARSSIM Section 4.6, these values are compared directly to the DCGLw. The comparison and the results are presented in Table 4. The sample mean and median values were less than the DCGL. FSS Outside Area Class 2 F8300142 FINAL STATUS SURVEY F8300142 Table 4, Data Assessment Results Number of Samples:

10 Median:

• 2,606

• Mean: 2,572 Static Data Standard Deviation:

247 Maximum:

2,826 Adiusted N Value:

• 10 S+ Value: 10 Critical Value: NA Sufficient samples collected:

• .Pass Maximum value <DCGLw: Pass Median value <DCGLw: Pass* Mean value <DCGLw: Pass* Maximum value <DCGLemc:

NA Siqn test results:

NA 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 2 survey and the sample results are consistent with that classification.

No individual measurement exceeded the DCGL. 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 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 f 8300142 meets the release criteria of 1OCFR20.l402.

4 FSS Outside Area Class 2 F8300l42 Attachment 1 Maps January 30, 2017 Survey Unit F8300142 l.{) l.{) F8300142A00003 P = 2,614 dpm/100 cm2

• F8300142A00010 P = 2,598 dpm/100 cm2 N F8300142A00007 P = 2,652 dpm/100 cm2 ..-Outside Area Class 2 SMUD Can ract Na.: 4500091426 Location:

Rancho Seca Task: Final Status Surve Approved by. Drawing Na.: NA

Description:

Drawn B . QC'd: Approval date: Date: Rev No.: Page 1 Io o.25 0.5 o. 75 ft rn F8300142A00006 I I = 2,826 dpm/100 dm2 I I I i F8300141 I I r F8300142A00008 I ! i I

.. . ,. F8300142A00002 P = 2,394 dpm/100 F8300142A00004 P = 2,576 dpm/100 cm2 F8300142A00009 P = 2,826 dpm/100 cm2 F8300142 F8300142A00001 = 2,015 dpm/100 0 1 1 2 2 3 3 4 4 5 5 Att. 1 Maps N 6 6 7 F8300142 Attachment 2 Instrumentation January 30, 2017 Survey Unit F83000142

'..-,:.:I

.* Beta Static Measurement Table 2-1. Survey Unit Instrumentation

. . . . * * * ; * * . Minimumnetectable A.

... * **.*

1nstru#!ent

• , . * .

Ludlum Model 2350-l Ludlum Model 44-116 B Detector Beta -522 dpm/100 cm2 13.2% -.... ' . Calibrati0,n

• :Dµe 317897/331972 2/10/17

• 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 12 months. Calibration due date indicates the date by which the detector must be calibrated again. cm2 = square centimeters cpm = counts per minute dpm = disintegrations per minute Page 1 Att. 2 Instrumentation F8300142 Static Measurement MDA Beta Survey Type PR331972 Detector Number 201 Background count rate (cpm) Count Time (min) 0.132 Efficiency 100 Area of Detector

( cm2) 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 (N.UREG 1507) Where: Br Background Countrate t Count Time (min) E Efficiency A Area of detector

( cm2) Static MDA 522 dpm/100 cm2 Page 2 Att. 2 Instrumentation F8300142 Att. 3 Investigation Attachment 3 Investigation January 30, 2017 Survey Unit F8300142 (none) F8300142 Attachment 4 Data Assessment

.January 30, 2017 Survey Unit F8300142 Histogram for Beta Static Activity (dpm/100 cm2) Outside Area Class 2 2027 '"" 218'3 mo 2351 ,.,, >513 Page I Att. 4 Data Assessment

,,,. F8300142 ! N\Ml'b8ldVall1M Minm.ni M ....... SD Skewne:s K1Mtoii1 0Me<!r'I 0Me<iari

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I I nM01e8N I 2.82'5.76 247.461 *1261 l.971 2.571971 2.6£6.Qil I I I 'I i ! I 11 I > I ti I < ""' i *1.5 *1.0 Page 2 -0.5 no Theoretical Quantiles (Standard Normal) Att. 4 Data Assessment 0.5 1.0 1.5 F8300142 Activi> Mian*2572 Sd ... 247.5 SIOcJ.i .. 246.2 Ca1dsti:in.A*0.1JJ&

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