ML17065A069

Rancho Seco Nuclear Generating Station - Final Status Survey Summary Report, January 30, 2017, Iosb Outside Area Class 1, Survey Unit F8300141

ML17065A069
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: ML17065A069 (14)

Text

Approved By: Rancho Seco Final Status Survey Summary January 30, 2017 IOSB Outside Area Class 1 Survey Unit F8300141 FSS Engineer Date: Manager, Rancho Seco Assets }-30 *f7 FINAL STATUS SURVEY F8300141 Survey Unit: F8300141, foterim Onsite Storage Building (IOSB) Outside Area Class 1 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 l Survey Unit, buffered by a Class 2 Survey Unit which will be addressed in separate reports.

The remainder of the outside area 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 10 m2 or land areas less 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 Jess than one square meter (0.37 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 based upon professional judgment in accordance with MARSSIM guidance and approximately 100% of the area scanned.

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

2. FSS Outside Area Class 1 F8300141 FINAL STATUS SURVEY F8300141 Table 1, Survey Unit Design Parameters

• . .. . .. comments

'* Survey PackaQe:

F830 Outside Asphalt Class 1 Survey Unit: 014 Class 1 SU Area (m2) 0.37 0.37 m2 Evaluator:

JR DCGLw: 43,000 Gross Activity DCGL Area Factor 22.1 DTBD-05-003 DesiQn DCGLemc (dpm/1 OOcm2): 950,300 DCGLemc:

950,300 LBGR: 21,500 Default=

50% DCGL Sigma: 513 Generic Sigma Type I error: 0.05 Type II error: 0.05 Predominant Nuclide Cs-137 Sample Area (m2) N/A Total Instrument Efficiency:

0.130 Total Area Scanned (m2): 0.37 Scan CoveraQe

(%) . ; 1 Class 1 Choosing

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

• , .. ' :** \: , ...... : . :::c9mments*

. > *** . ..*:: ; " ....... *./*-.'.:.

.. :!

• Z1-a: 1.645 Z1-B: 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:

5 Judgement N-Value+20%:

NIA Survey Results:

A total of 5 direct measurements were made in F8300141.

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 I F8300141 FINAL STATUS SURVEY F8300141 Table 2, Static Measurement Results ,. *:: :* .Number,

. * < '$am,pJe:#*

. *. . . : Beta (cpm)

.. 1 F8300141A00001 370 2,803. 2 F8300141A00002 353 2,674 3 F8300141A00003 313 2,371 4 F8300141A00004 347 2,629 5 F8300141A00005 350 2,652 Table 3 contains the statistical summary of the static measurement data for the Outside Area Class 1. Table 3, Beta Summary Statistics Beta Static Outside Asphalt Class 1 Mean Median Standard Deviation Minimum Maximum Count Survey Unit Data Assessment:

2,626 2,652 158 2,371 2,803 5 The survey design was based upon professional judgement and resulted in 5 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. 3 FSS Outside Area Class 1 F8300141 FINAL STATUS SURVEY F8300141 Table 4, Data Assessment Results *-* ,' '*.' . Number of Samples:

.5 Median: 2,652 Mean: 2,626 Static Data Standard Deviation:

158 Maximum:

2,803 .. ',' **; .* . ' ..... _..., ... : Sufficient samples collected:

Pass Maximum value <DCGLw: Pass Median value <DCGLw: Pass

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

N/A. Sign test results:

NIA . The survey unit passes all conditions:

Pass Survey Unit Investigations and Results:

No investigations were required for either direct or scan measurements collected for the FSS 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 l 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 1 survey based on the results ofthe investigation survey. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the .L TP. 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 F8300141 meets the release criteria of 10CFR20.1402.

4 FSS Outside Area Class I F8300141 Attachment 1 Maps January 30, 2017 Survey Unit F8300141 j1 I I l[ \ I 05 0.7511 w F8300141A00003 = 2,371 dpm/100 cm2 F8300141A00002 = 2,674 dpm/100 cm2 F8300141A00005 = 2,652 dpm/100 cm2 F8300141A00004 = 2,629 dpm/100 cm2 F8300141A00001 == 2,803 dpm/100 cm2 N TIDEWATER IN I RAOlOLOGICALSt::r.vrccs ass 1 SMUD Approved by. Orcw'oq No.: NA Oea:criptlcn

l)Ut!"1!.dc ArN Cl:JS!> l I I ! I l I ' I I I I Drawn B . 0 1 2 2 3 3 4 4 5 5 6 6 7 QC'd, l FlPP"'I" Oohr. 01£101/ AQ,provol dote: Rev No.; I Page I Att. I Maps F8300141 Attachment 2 Instrumentation January 30, 2017 Survey Unit F83000141 Measurement Type Beta Static Measurement Table 2-1. Survey Unit Instrumentation Instrument Type Ludlum Model 2350-1 Ludlum Model 44-116 B Detector Minimum Activity*

Beta -515 dpm/100 cm2 netector Efficiencies 13.2% Calibration Due.Dateb

' . . \ . . 317897/331972 2/10117

• 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 Pagel Att. 2 Instrumentation F8300141 Static Measurement MDA Beta Survey Type PR331972 Detector Number 195 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 (NUREG 1507) Where: Br Background Countrate t Count Time (min) E Efficiency A Area of detector (cm2) Static MDA 515 dpm/100 cm2 Page 2 Att. 2 Instrumentation F830014l Att. 3 Investigation Attachment 3 Investigation January 30, 2017 Survey Unit F8300141 (none) F8300141 Attachment 4 Data Assessment January 25, 2017 Survey Unit F8300141

---

. ----------*----

---

---

2375 2418 2505 2591 2720 Page 1 Att. 4 Data Assessment

---

*----*--------*--------

---

27G4 2007 F8300141 I Nwbef ofV-Wes I I SD Skewnes!: Kll'losis eJM""' e!Mea.n elN°"""'DiWW>on OLet:tSN : 0More9iM I I I 51 2.371.Zl I 2,003.0J 157.511 -1.15 2.5< Z£2l.7GI 2.651.52 I ! I i I Q..Q Plot for Beta Static Activity (dpm/100 cm2) Outside Area Class 1 2700 2400 *1.2 -0.9 -0.6 ru M U Theoretical Quantiles (Standard Normal) Page2 Att. 4 Data Assessment 0.6 0.9 1.2 F8300141

'ActivQ ti .5 MN'ii*262S Sd* 157,5 Slope* 1623 Intercept

.. 2626 Cooel4tion.

A* 0.9JJ 8B .. FHioe