ML051520389

Final Status Survey Release Record FD-0600 Service Water Survey Unit 2

ML051520389
Person / Time
Site:	Maine Yankee
Issue date:	05/24/2005
From:	Olsen C, Packer J, Pillsbury G, Randall D, Tozzie R Maine Yankee Atomic Power Co
To:	NRC/FSME
References
FD-0600-02, Rev 0
Download: ML051520389 (21)

Text

. . .

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-0600 SERVICE WATER SURVEY UNIT 2 Prepared By: Ah £. , 4 A/ Date: S-/9-0 .

FSS Engineer - Signature Printed Name Reviewed By: Date: lI9/oS S

FSS did- Signaturc t;~2.1-l Printed Name Reviewed By: Date: (9, tt7g IndcrPde ;t evi Signature Approved By Date: 3 S-erinten §ignatur Printed Name Approved By: __ , Date: .

. FS, MOP - Signature Printed Name Revision 0

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FD-0600 SERVICE WATER SURVEY UNIT 2 A. SURVEY UNIT DESCRIPTION Survey Unit 2 is the discharge portion of Survey Area FD-0600, Service Water. The Service Water System consisted of two buried inlet pipes that carried seawater through component cooling heat exchangers then discharged through a single buried pipe to the Forebay Seal Pit.

The discharge side of the system received effluent discharges from the connected radiological liquid effluent pipe. The liquid effluent pipe had detectable levels of loose and fixed contamination, and was removed prior to performing the survey.

The survey area consists of one Class 3 piping survey unit'. The classification of individual piping sections was based on their potential for contamination, this determination was based primarily on location. Thc survey classes for particular sections are specified in Attachment 5A of the License Termination Plan (Reference 1).

Survey Unit 2 consists of the outlet side piping and was surveyed in two phases as the locations became accessible. Phase 1 consisted of concrete pipe while Phase 2 consisted of metal pipe. The surveyed portions are located near grid coordinates 407375N, 623700E (Phase 1) and 407625N, 624000E (Phase 2) using the Maine State Coordinate System (West Zone) NAD 1927. FD-0600 Survey Unit 2 is shown in relation to other major site structures in map FDO600-02 SITE. All maps referenced in this release record are provided in Attachment 1 unless otherwise noted. The survey unit is approximately 322 m2 .

B. SURVEY UNIT DESIGN INFORMATION The area was designated a Class 3 piping survey unit per Attachment 5A of the LTP. To allow for timing of system accessibility, it was designed and performed in two phases. Phase 1 was performed on the area just upstream of the Forebay Seal Pit in August of 2004, and Phase 2 was performed just downstream of the radwaste inlet header in May of 2005.

The survey unit design parameters are shown in Table 1. Given an adjusted relative shift of 3.0, it was determined that 14 direct measurements were required for the Sign Test; however, the number of samples was increased because the LTP also requires a minimum of 30 direct samples points (to accommodate an efficient field layout, 32 were taken).

FD-0600 Unit I was intended to include the buried portions of the inlet pipes. The survey was not performed as this piping section was excavated and removed.

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Direct measurement locations were determined by equally distributing the measurement locations along the circumference and length of the accessible areas of the piping. Locations are illustrated on the maps FDO600-02a and FDO600-02b.

The survey was also designed to include 10 scan grids for flat surfaces, each of approximately 0.73 m2 area (again see maps FDO600-2a, FDO600-2b). Instrument scan setpoints were approximately set at the DCGL plus background, as shown in Table 2-2 (Attachment 2).

To accommodate measurement geometry requirements for damp concrete surfaces and damp/rough metal surfaces, the 43-68 data was evaluated with damp concrete efficiencies, as appropriate. As an additional check, an ISOCS measurement was performed on the areas scanned for Phase 2 of the survey as shown on map FDO600-2c.

The 43-68 background values were established for each of the two phases of the survey based on local scaler measurements taken in the survey unit. These ambient background values, listed in Table 1, were used to establish net activity for direct measurements, scan alarm setpoints, and to confirm the scan MDCs used were appropriate.

The instruments used in this survey are listed by model and serial number in Attachment 2 (Table 2-1). Scan MDCs are also listed in Attachment 2 (Table 2-2) and are compared to the DCGL and the investigation level. As shown in this table, the scan MDC is less than the scan investigation level in all cases, thus providing high confidence (95% or higher) that an elevated area would be detected in the scanning process.

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TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 322m 2 ll Based on an LBGR of 4,900 Num. ofDircdpm/lOOcm2, sigma2 of 727 dpm/100 Number of Direct 30 cm2 , and a relative shift of 6.7.

Measurements Required Type I = Type 11= 0.05, N = 14 (Minimum =30 per the LTP)

Sample Area N/A Class 3 Sample Grid Spacing N/A Class 3 Scan Grid Area 0.73 m2 12" bands of 30" ID pipe per scan grid Area Factor N/A Class 3 Scan Survey Area 7.3 ni2 (2.27%) Class 3 (1-10%) required

Background

PHASE IAmin 30cm 43-68 Direct and Scan 5,807 dpm/l0O cm2 Efficiencyt 0.0492 EC 033-01 (damp concrete surfaces)

PHASE 2 43-68 Direct and Scan (metal piping, damp 4,646 dpm/100 cm2 Ambient ( cpm) concete ef. ~Efficiency urfae = 0.0492 EC 033-0 1 conservatively applied)

Scan Investigation Level DCGL plus See Table 2-2 (Attachment 2) background DCGL 9,800 dpm/100 cm' LTP, Rev. 3 Design DCGLEMC N/A Class 3 C. SURVEY RESULTS Thirty-two direct measurements were made in Survey Unit 2. Once corrected for ambient background (material backgrounds were not used), all direct measurements were less than 50% of the DCGL. The resulting data are presented in Table 2 below. No verified alarms were received during the surface scans with the 43-68 probe. The ISOCS measurement performed in Phase 2 was less than MDA for Cs-137 and detected 289 dpm/l00 cm2 for Co-60 (3% of the DCGL). Therefore, no investigations were required.

2 Design sigma Is based on the sigma value from the LTP for the Turbine Building (BO500).

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TABLE2 DIRECT MEASUREMENTS Gross Activi Net Activity Sample Location 1cm (Table Background Subtracted) 2

___cm__dprn/lOO dpm_____ cm FDO600-02-COOI 9,227 3,420 FDO600-02-C002 8,775 2,968 FD0600-02-C003 8,808 3,000 FDO600-02-C004 8,679 2,871 FDO600-02-C005 7,114 1,307 FD0600-02-C006 6,614 807 FDO600-02-C007 7,082 1,274 FDO600-02-C008 7,678 1,871 FDO600-02-C009 7,872 2,065 FD0600-02-COIO 6,630 823 FDO600-02-C01 I 6,888 1,081 FDO600-02-CO12 6,388 581 FD0600-02-C013 7,436 1,629 FDO600-02-C014 7,291 1,484 FDO600-02-C015 7,243 1,436 FDO600-02-C016 7,662 1,855 FDO060-02-M022 5,565 919 FDO600-02-M023 5,710 1,065 FDO600-02-M024 5,565 919 FDO600-02-M025 5,662 1,016 FDO600-02-M026 5,226 581 FDO600-02-M027 5,646 1,000 FDD600-02-M028 5,856 1,210 FDO600-02-M029 5,581 936 FDO600-02-M030 7,227 2,581 FDO600-02-M031 7,275 2,629 FDO600-02-M032 7,485 2,839 FDO600-02-M033 7,598 2,952 FDO600-02-M034 5,259 613 FDO600-01-M035 5,114 468 FDO600-02-M036 4,920 274 FD0600-02-M037 4,372 -274 Mean 6,733 1,506 Median 6,985 1242 Standard Deviation 1,257 952 Sample Range 4,372 to 9,227 -274 to 3,420 FD-0600-02, Revision 0 Page 5 of 21

D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No investigations were required as there were no verified scan alarms.

E. SURVEY UNIT DATA ASSESSMENT An analysis of the direct sample measurement results, including the mean, median, standard deviation, and sample result range, are provided in Table 2. Without subtracting background, all direct measurement results were below the DCGL. The maximum direct sample result with background subtracted was equivalent to 3,420 dpm/l00 cm2 .

When adjusted for background, the mean residual contamination level is 1,506 dpmll 00 cm 2 .

This is equivalent to an annual dose of 0.0004 mrem3 .

There were no verified alarms, and therefore there were no investigations required.

F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with Survey Unit 2, including relevant statistical information. Based on survey unit direct measurement data, this attachment provides the Sign Test Summary, Quantile Plot, Histogram, and Retrospective Power Curve.

1. The Sign Test Summary provides an overall summary of design input (Table 1) and resulting calculated values used to determine the required number (N) of direct measurements (per LTP Section 5.4.2). The Sign Test Summary is a separate statistical analysis that also calculates the mean, median, and standard deviation of the direct measurements.

The Sign Test Summary table calculated the total standard deviation by propagating the individual standard deviation values used in the subtracted background survey design (using the square root of the sum of the squares method).

The critical value and the result of the Sign Test are provided in the Sign Test Summary table, as well as a listing of the key release criteria. As is shown in the table, key release criteria were satisfied, with one exception. An "investigate" flag was produced because the direct measurement sigma exceeded the design sigma, however, sufficient power is evident, particularly when one considers that 32 samples were taken for the FSS of this survey unit.

3 From Table 6-11 of the LTP, the buried piping dose is2.52E-03 mrem/y; therefore, (1,506/9,800) x 2.52E 0.0004 mremly.

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2. The Quantile Plot was generated from direct measurement data listed in Table 2 and indicates general symmetry about the median. The data set and plot are consistent with expectations for a Class 3 survey unit. There is no reason to conclude that the data set represents other than random variations in a Class 3 survey unit. It also should be noted that the maximum net activitly (3,420 dpm/100 cm 2 at location C001) is well below the DCGL of 9,800 dpm/l 00 cm .

3. A Histogram Plot was also developed based on the direct measurement values. This plot shows that the direct data were essentially a normal distribution.

4. A Retrospective Power Curve was constructed, based on FSS results. The curve shows that this survey unit, having a mean residual activity at a small fraction of the DCGL, has a high probability ("power") of meeting the release criteria. Thus, it can be concluded that 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.

As mentioned in Section B, an ISOCS measurement was obtained at the Phase 2 location of the survey. The measurement results indicated residual Co-60 activity of 289 dpm/100 cm2 which is well below the DCGL of 9,800 dpm/100 cm 2 .

G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class 3 area; the FSS results were consistent with that classification. The direct measurement sample standard deviation was greater than the design sigma; however, a sufficient number of sample measurements were taken.

H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 2 was designed, performed, and evaluated in the August 2004 to May 2005 time frame. The only subsequent LTP changes (with potential impact to this FSS) were provided in the proposed license amendment related to modifications of the activated concrete remediation plan submitted September 11, 2003 (Reference 4) and the issuance of Revision 4 of the LTP (Reference 5). Changes represented in these subsequent proposed license amendments have been evaluated and have no impact on the design, conduct, or assessment of the final status survey of Survey Unit 2.

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I. CONCLUSION The FSS of this survey unit was designed based on the LTP designation as a Class 3 area.

The survey design parameters are presented in Table 1. The required number of direct measurements was determined for the Sign Test in accordance with the LTP. As presented in Table 2, all beta direct measurements were less than the DCGL of 9,800 dpm/100 cm2 .

A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied. The direct measurement sigma was determined to greater less than that used for design, but a sufficient number of samples were taken to produce adequate power.

The Retrospective Power Curve shown in Attachment 4 confirmed that sufficient samples were taken to support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and the data quality objectives were met. Attachment 4 also revealed that direct measurement data represented essentially a normal distribution, with variance consistent with expectations for a Class 3 survey unit.

The scan survey design for this survey unit was developed in accordance with the LTP with significant aspects of the design discussed in Section B and Table 1. Scanning resulted in a no verified alarms (Section C). Since there were no alarms, the survey unit was determined to satisfy the elevated measurement comparison unity rule per LTP methodology.

It is concluded that FD-0600 Survey Unit 2 meets the release criteria of IOCFR20.1402 and the State of Maine enhanced criteria.

J. REFERENCES

1. Maine Yankee License Termination Plan, Revision 3, October 15, 2002

2. Maine Yankee letter to the NRC, MN-02-061, dated November 26,2002

3. NRC letter to Maine Yankee, dated February 28,2003

4. Maine Yankee letter to the NRC, MN-03-049, dated September 11, 2003

5. Maine Yankee License Termination Plan, Revision 4, February, 2005 FD-0600-02, Revision 0 Page 8 of 21

Attachment 1 Survey Unit Maps FD-0600-02, Revision 0 Page 9 of21

DcmaisioneiYnkeeam Decommissioning Team aine Yankee DecommissioningProjectSurvey Form aIneYake Map ID #: FDO600-02 SITE Survey Type: E2 Characterization rI Turnover N Final Status Survey I Survey Area Name: Service Water Piping System - Discharge 623.000 E 623.500 E 624.000 E 624.500 E 525.000 E

'- FDO600 - Survey Unit 2 MN I .00 1 I Access Points 0 400 goo 12010 FD-0600-02, Revision 0 Page 10 of21

Mahe ok-eeT Maine Yankee Decommisslonlng Project Survey Map Mcap ID# FDO600-02a DecrniW-an Tecm__= w -

SurvtyTypo: j I Charoctoftzlon Tumover

• FndStohswe IsurveymkaNa Ne: ServiceWafterPipingSystemr-Dlschare FDO600 SU2 Service Water System Piping Direct and Scan Locations Access Upstream of Seal Pit/Thrust Block 1 AREA OF DETAL (30' Service Water Discharge Pipe) i Thrust Block iA (gi 5C. 1, I

C~O2)cool erc__-

cm) _ N Nrvic \ (@of roeoed'Pe

(@ 30cm Excavation Pit _

(@ 45cm) -(@45cm) 9 y) C017 1 C019 l

%1.)Z7 30cm21 4 , *< / i li Service Water Discharge DIRECT LOCATIONS (30" Inner Diameter)

I Servic :e Water Discharge SI SCAN LOCATIONS NOTE: DASHED LINES REPRESENT 2 PROBE LENGTHS (appx. 30cm).

DIRECTS TAKEN EVERY 15cm. (30" Inner Diameter)

(Drawing Not to Scale) FD-0600-02, Revisi on 0 Page I1of 21

Molne Yankee

_Decomn-ssionina Tecrn_

Maine Yankee Decommissioning Project Survey Map 1,Map ID# FDO600-02bl SumveyT',1 ° 1 Characterizoaton Turnover

• Firid Stas SuvoSyw AreANeorName: Service Water Piping System - DIschorge FDO600 SU2 Service Water System Piping Direct and Scan Locations Access at Service Bldg/Turbine Bldg Interface AREA OF DETAIL 130" Service Water DIscharge Pipe)

Serrlie URler.Acceu eMxfI .RtWal pipe)

Ml023 02 M024 M022 M02 M8 , ,.M

( @,5cm) 1 0 "1'(@Cm Se e W ,' r Dg " M027 33m 6)j M027 9 M0383 4

)@4cm) CA \ t?4cm) / I -IO39'g 30cm) @30m "  ;\ '

(@ 14cm5c'm) , ' '

INA DIRECT LOCATIONS \- -- - - -- ,

(30" Inner Diameter)32 II Service Water Discharge SCAN LOCATIONS

. NOTE: DASHED LINES REPRESENT 2 PROBE LENGTHS (appx. 30cm). (30" Inner Diameter) I

!DIRECTS TAKEN EVERY 15cm. I (Drawing Not to Scale) FD-0600.02, Revision 0 I Page 12 of21 I

.- - .- ......- - .- - ..-I

Mdne Ycnkee Decomrrdsskonlna Team Maine Yankee Decommissioning Project Survey Map Map ID# FDO600-02c

&^rveylpo: Charactelzaroln TunLover U FbIdStaotsSrvey ;SurvArooNcne: ServiceWaterPipingSystem-Discharge FDO600 SU2 Service Water System Piping ISOCS Scan Location Service Bldg/Turbine Bldg Interface Access AREA OF DEWL (30 Service Water Discharge Plpe)

Serr"ee Ulierrets Mm1llettal p11

_ _1

-- N ISOCS M043 (Modeled for 5' Depth)

Unit Service Bldg Side

ervice Water Discharge ISOCS SCAN LOCATION NOTE

ISOCS Detector to be Positioned Just Inside Plane of Pipe Opening.

. (Drawing Not to Scale) FD- 40600-02, Revision 0..

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Attachment 2 Survey Unit Instrumentation FD-0600-02, Revision 0 Page 14 of21

TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN Probe SIN (type) 1929 148932 (43-68) 2490 177992 (43-68-5) 1929 j 177991 (43-68-5) J ISOCS l MDC

" ent Z 1 46 dpvmlOocm 2 Co-60 I / u) I 113dpm/100cmz Cs-1371 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL 43-68 43-68 Parameter Phase 1 - 30"dia. Phase 2 - 30"dia.

damp concrete surfaces damp metal surfaces Scan MDC 4,841 4,841 (dpm/100 cm 2) Note 1 Note I DCGL 2 (dp I00 CM ) 9,800 9,800 Investigation Level 15,566 14,437 (Alarm setpoint) DCGL plus (- DCGL plus

( 100 cm2) background) background)

NOTE: 1. The scan MDC developed for the 43-68 was determined by adjusting the LTP Table 5-6 value for the change in efficiency.

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Attachment 3 Investigation Table (No Investigations Required)

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Attachment 4 Statistical Data FD-0600-02, Revision 0 Page 17 of 21

Survey Package FDO600 Unit 2 Surface Sign Test Summary Survey Package: FDO600 Service Water Piping Survey Unit: 02 _ _

Evaluator: DR DCGLW: 9.800 DCGL.,: 9,800 NIA Class 3 SU LBGR: 4_900 Sigma: 727 Type I error: 0.05 Type II error 0.05 Total Instrument Efficiency: 4.9% data adjusted for various effs.

2 126 Detector Area (crn): _____________________________

Choosing 'NIN sets material Material Type: N/A background to 10, At Zl, Izr.645__

Zap:l 1.645 Sign p: 0.99865 Calculated Relative Shift: 6.7 Relative Shift Used: 3.0 Uses 3.0 If Relative Shift >3 N-Value: 11 N-Value+20%: 14 Number of Samples: 32 Median: 1,242 Mean: 1.506 Net Static Data Standard Deviation: 952 Total Standard Deviation: 952 SRSS Maximum: 3,420 Adjusted N Value: 32 So Value: 32 _ _ _

Critical Value:21 Sufficient samples collected: Pass Maximum value <DCGLw Pass Median value <DCGL,: Pass Mean value <DCGLw, Pass Maximum value <DCGLT,: Pass NIA Class 3 SU Total Standard Deviation <=Sigma: Investigate SU passes. See Section F Sign test results:, Pass The survey unit passes all conditions: Investigate SU passes 5/23/OS 10:17 AM FDO600-5U2-SurfaceSign FD-0600-02, Revision 0 Page ISof21

FDO600 SUw2 Quantile Plot 4000 E

0 00.

3000

• Activity (dpm/1 00 0

"oIj 2000 cm2) at I O eV t" 1000 Median (dpm/100 5.

40

-W cm2) i........... ......

0 cm

-1000 0 25 50 75 100 Percent I

I+ .- -. . . -.-. I

One-Sample T-Test Report Page/Date/Time 2 5/23/05 10:54:52 AM Database C:\Program Files\NCSS97\FD0600 SU-2.SO Variable C2 Plots Section Histogram of FD-0600, SU-2 C) 0.

E co E-z2 Activity (dpmllOO cm2)

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One-Sample T-Test Power Analysis Page/Date/Time 2 5/23/05 10:56:13 AM Chart Section Retrospective Power Curve 1.0.-I -*0~

0.84-L.-

a) 0.64-0 0-0.41-0.2+

0.0 I 1000 3d00 5000 7000 90oo 1100 Survey Unit Mean (dpm/100 cm2)

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