ML043640306

Maine Yankee Final Status Survey Release Record FR-0400 Forebay Survey Unit 6

ML043640306
Person / Time
Site:	Maine Yankee
Issue date:	12/19/2004
From:	Cooper W J, Pillsbury G, Randall D B, Tozzie N Maine Yankee Atomic Power Co
To:	NRC/FSME
References
MN-04-060, RA-04-118 FR-0400-06, Rev 0
Download: ML043640306 (31)

Text

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0400 FOREBAY SURVEY UNIT 6 Prepared By: 69e& / AcZ e 4 / o- 2 SO -O9 FSS Engineer -Signature P Spe a ort-Signature

,2,<Print/edl Name Date: Reviewed By: .tf z ;e_> &S~pe7 -ignture Printed Narm Date: Reviewed By:co o/ /6t Meffdent Reviewer Sintr Approved By: a h 7ae: f~, MOP Sg natnure/Printed Name Date: Approved By: 2 h yfs tINS, MOP -Signature muse. A~g-e~Printed Name MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0400 FOREBAAY SURVEY UNIT 6 A. SURVEY UNIT DESCRIPTION Survey Unit 6 is located within Survey Area FR-0400, the Forebay. The Forebay is located south of the radiologically Restricted Area of the site at coordinates 407250 N and 623700 E (See Map FR 0400 SITE, Attachment 1). The Forebay is a large, rock-lined basin in which condenser cooling water collected prior to its release through the diffuser system out to the ocean. During plant operation, the Forebay/Diffuser System was the licensed discharge path for liquid, radiological effluents.

After plant shutdown, stop logs were set in place at the Forebay end of the diffuser to isolate the Forebay in order to prevent the release of Forebay sediment into the river during remediation activities.

Two earthen dikes make up the north-south running walls of the Forebay with concrete walls at the extreme north and south ends to support the circulating water and diffuser pipes. The dike walls form a V at the southern end of the Forebay (adjacent to Foxbird Island). The diffuser discharge pipes originate at the notch of the V. A concrete dam, or weir, runs in the east west direction at the northern end of the Forebay and creates a small, water-filled area called the sealpit. The sealpit maintained a water seal over the circulating water pipes to prevent loss of flow with tidal fluctuations.

Survey Unit 6 consists of the concrete on the south side of the weir and the discharge structure at the south end of the Forebay. This includes both above water and submerged concrete.

The Survey Unit has an above water surface area of approximately 336 m 2 , the submerged portion is approximately 220 m 2.B. SURVEY UNIT DESIGN INFORMATION The Forebay received the liquid radioactive discharges from the plant. It was known to have been contaminated to levels in excess of the release limits and extensive remediation activities including underwater dredging, underwater vacuuming, and dry surface vacuuming were performed.

It should be noted that concrete surfaces were not remediated prior to the final status survey. Given the high probability of residual contamination, the Forebay was classified as Class 1.Revision three of the Maine Yankee License Termination Plan (LTP)l states that the Forebay dose from residual radioactivity "is so insignificant and the probability so low that an individual would be able to successfully place a viable well within the Forebay, survey measurements of the Forebay surfaces including rip-rap will be limited".

As a result, the survey design for the Forebay is a reasonable approach to demonstrate compliance with the release criteria while not necessarily meeting all of the requirements for a "MARSSIM" survey. Consequently, the submerged concrete was not completely surveyed, as stated in the technical basis document.

The submerged concrete was spot-checked (biased measurements) using the ISOCS in situ gamma spectroscopy system.LTP, Revision 3 refers to the LTP submitted in October 2002 (Reference I) as amended by the MY's addenda of November 2002 (Reference 2). LTP, Revision 3 was approved by the NRC in February 2003 (Reference 3).FR-0400-06, Revision 0 Page 2 of 31 The survey unit design parameters are shown in Table 1. Only accessible areas located between the water and demolition lines wvere considered in the design. Ledge areas within the aforementioned limits were included in the direct measurement locations.

A minimum number of 14 direct samples were required for the Sign Test (23 were taken). Each sample measurement location was determined using a random start point and a square grid. These locations are presented on survey maps FRO400-06b, FRO400-06e, FRO400-06h, FRO400-06k and FRO400-06 DP (Attachment 1). Once the direct readings were completed, removable contamination samples were obtained at each direct measurement location.The survey unit design included 126 individual scan grids (refer to maps FRO400-06c, FRO400-06f, FRO400-06i, and FRO400-061, Attachment 1). Three scan grids originally appearing on scan grid map FRO400-06F were eliminated from the survey due to a difference between the print dimensions and the as built dimensions of the concrete structure.

Sizes of individual scan grids were 3 m 2 or less in area. For convenience, scan grids along the East and West banks of the south intake structure were sized to I m x 3m, the balance of the scan grids were nominally I m x I m.Instrument scan setpoints were conservatively set below the DCGLENc, as shown in Table 2-2 (Attachment 2).Background values were established, for each particular instrument probe application based on ambient background values in the survey area and previously established material backgrounds.

These 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, the investigation level, and the DCGLEN1c.

As shown in this table, the scan MDC is less than the scan investigation level in all cases, thus providing a high confidence (95% or higher) that an elevated area would be detected in the scanning process. Further, since the investigation level at the alarm setpoint was always less than the design DCGLENc, no EMC sample size adjustment was necessary.

FR-0400-06, Revision 0 Page 3 of 31 TABLE I SURVEY UNIT DESIGN PARAMETERS l Survey Unit Design Criteria Basis Area 336 m 2 Above water area of the SU Based on an LBGR of 9,000 Number of Direct dpm/I00 cm 2 , a sigma 2 of 220 Measurements Required 14 dpm/O00 cm 2 , and a relative shift (adjusted) of 3.0.Type I = Type 11 = 0.05 Sample Area 24 m 2 336 m/ 14 samples Sample Grid Spacing 4.9 m (used 4.75) (24)~2 Area Factor 2.08 50 m" / 24 m" Scan Survey Area -258 mI 100% of accessible concrete area Background r :;43-68 Scan (flat surfaces) 2863 dpm/l 00 cm/ Ambient and Material Scan Investigation Level Ambient Background See Table 2-2 (Attachment 2)___ ___ ___ ___ ___ ___ __ plus D CG L DCL18,000 dprnllO 0cm 2 Forebay' technical basis document______18,000_______

______(Reference 4)DCGLEMC 37,440 dpm/100 cm 2 Area Factor x DCGL C. SURVEY RESULTS Twenty-three direct measurements were made in Survey Unit 6. The direct measurement data are presented in Table 2 below. All direct measurements were below the DCGL.The scan process was performed in accordance with FSS requirements for all accessible areas. The scan surveys identified no locations with verified alarms that would indicate potentially elevated activity.

Similarly, underwater area spot checks did not indicate elevated levels of activity (i.e., all levels < MDC), based on in situ gamma spectroscopy using an HPGe detector with an MDC of approximately 10% of the DCGLEMCc.

Therefore, no investigations were required.2 Sigma was determined during the background evaluation performed for FR-0400 Survey Unit 3.FR-0400-06, Revision 0 Page 4 of 31 TABLE 2 DIRECT MEASUREMENTS Gross Activit ~ Net Activity Sample Number l/ cm) (Table I Background Subtracted)

_____ _____ ___cm (dpm/100_cm

)2 FR0400-6-C001 3,284 421 FR0400-6-C002 2,882 18 FR0400-6-C003 2,405 -458 FR0400-6-C004 3,462 598 FR0400-6-C005 3,498 635 FRO400-6-C006 2,814 -49 FRO400-6-C007 3,211 348 FRO400-6-C008 3,034 171 FR0400-6-C009 2,973 110 FR0400-6-COIO 3,162 299 FR0400-6-COI 1 3,120 256 FR0400-6-C012 4,243 1,380 FRO400-6-C013 2,411 -452 FRO400-6-C014 2,619 -244 FRO400-6-CO15 5,861 2,998 FRO400-6-C016 6,716 3,852 FRO400-6-C017 3,333 470 FRO400-6-CO 18 4,090 1,227 FR0400-6-C019 2,302 -562 FRO400-6-C020 2,821 -43 FR0400-6-C021 5,147 2,283 FR0400-6-C022 2,967 104 FRO400-6-C023 3,407 543 Mean 3,468 605 Median 3,162 299 Standard Deviation 1,100 1,100 Range 2,302 -6,716 -562 -3,852 D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No verified alarms wvere received; therefore, no investigations were required.FR-0400-06, Revision 0 Page 5 of31 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 a background, all sample measurement results were less than the DCGL. The mean value of background-subtracted activity is 3.36% of the DCGL limit. This would be equivalent to an annual dose rate of 0.01 mremly 3.The maximum net direct sample result is equivalent to 21.4% of the DCGL. The sample standard deviation is larger than the design sigma, however, no additional measurements were required due to the power of the Sign Test (i.e., relative shift is unaffected).

The scan measurements, which were performed in this survey package, produced no verified alarms. The ISOCS results were consistent with the scan measurements.

F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with this Survey Unit, including relevant statistical information.

Based on survey unit direct measurement data, this attachment provides the Sign Test Summary, Quantile Plot, Histogram, and Retrospective Powver 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 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, all of the key release criteria, except for the final sigma, were clearly satisfied for the FSS of this survey unit. Although the design sigma was less than the final standard deviation, the relative shift was unaffected and the number of samples remained adequate for the Sign Test.2. The Quantile Plot was generated from direct measurement data listed in Table 2. The data set and plot are consistent with expectations for a Class I survey unit. All of the measurements are well below the DCGL of 18,000 dpm/100 cm 2.3. A Histogram Plot was also developed based on the direct measurement values. This plot shows that the direct data were essentially a log-normal distribution with five outliers.(The high values were all on or near ledge which has a high NORM content.)4. A Retrospective Power Curve wvas 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.3 This annual dose equivalent is based on LTP Table 6-1 1, which shows the contaminated concrete dose contribution (for surfaces contaminated at the DCGL) is 0.301 mrem/y.FR-0400-06, Revision 0 Page 6 of 31 As mentioned in Section B, removable contamination samples were obtained at each (direct)measurement location.

In that this survey unit did not involve a standing building, the removable contamination measurements were not applicable to release decisions for the survey unit. However, the samples were obtained and evaluated.

Except for one positive beta measurement of less than 5 dpmll 00 cm 2 , the alpha and beta activity were less than MDA values (< 2 dpm/1 00 cm 2 alpha, < 4.3 dpmll 00 cm 2 beta). Thus, in comparison with the mean survey unit net activity (Table 2), the removable contamination sampling effort indicated that the majority of activity is fixed.G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON THE EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class I area. The FSS results were consistent with that classification.

As discussed previously, the final standard deviation was greater than the design sigma. However, the survey design was not adversely affected.

Thus a sufficient number of samples were taken.H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 6 was designed and performed using the criteria of the approved Forebay Technical Basis Document (Reference

4) and LTP (Revision 3 Addenda).Subsequent LTP changes have been evaluated and have no impact on the design, conduct, or assessment of the final status survey of this Survey Unit.I. CONCLUSION The FSS of this survey unit was designed based on the LTP designation as a Class I 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 18,000 dpmll 00 cm 2.A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied.

The sample standard deviation is larger than the design sigma, however, no additional measurements were required due to power of sign test.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 log-normal distribution, with variance consistent with expectations for a Class I 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 no verified alarms; therefore, no investigations were required.In addition, while not part of the release decision criteria, removable contamination sampling confirmed that the majority of remaining activity in this survey unit was fixed.It is concluded that FRO400 Survey Unit 6 meets the release criteria of 10CFR20.1402 and the State of Maine enhanced criteria.FR-0400-06, Revision 0 Page 7 of 31 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-03-05 1, "Forebay Technical Basis Document," dated September 3, 2003 FR-0400-06, Revision 0 Page 8 of 31 Attachment 1 Survey Unit Maps FR-0400-06, Revision 0 Page 9 of 31 Maine Yankee i YI Map ID #: FR 0400 SITE Decommissioning Team Maine Yankee Decommissioning Project Survey Form Revised: 11-04-03 Survey Type: [] Remediation O Turnover

• Final Status Survey I Survey Area Name: Forebay Site Map 623,000 E 623.500 E 624,000 E 624,500 E 625,000 E o 0- 0 40 0 on 0 0 CD 0 0 g 0 g 0 8 0 Z Z Z Z Z Z SCALE MN Z---,E~~-N 0 400 800 1200 Note: Grid based on Maine State Coordinate System (West Zone) NAD 1927 FR-0400-06, Revision 0 Page IOof31 a'r9 UN-t I..44-l E cu.0 C WE E-.Li LDU C*+c, i)0oi FR 0400: FOREBAY Survey Unit 6, Forebay Concrete Direct Point Map 0 0> _Y o-C4 0 _o .S a)c U C 0 C.)o.0 4)0 U-E M 2 (U z 2: , 4).a C_, U, C LL a W 0 E C 0 (U N C2 0.I.-a)Wi lOm 5m* II T TL I --I iI IC0 2 -P-;-!-4--- --- -i--- ------CpQ~ ~C9O T 1 I CI1T.013I! I .; I l I I i I I C 01 I ! .!C0 ..Ir~ -IFTO6.... CO>..)-C0 2 0 ~9 0 O! T-i I-- F1---- 1'. ' T !-1-1-0 5m 1 Om 1 5m 20m 25m 30m 35)m 40m 45m 50m 55M L= 4.75m N= 14 SA= 336 sq-m (Area within DemolWater Line)

I i co Os cou 1. N C)U- C}j q.4 CO CD t.L CJ c..E.0.4...5.4.4 E a)U).O C C~ ._C._.U *0 S)'o 2 0 C 0 U 0 C)0)L2 4n E_, z co a)U)>5_.C U)U)Ln CU C U 0)E C.N 0 co I-)C.>5 C)Z.23 co FR 0400: FOREBAY Survey Unit 6, Concrete Weir Forebay Side ISOCS Spot Check Points # CO01 -C003 14.70rn .O ITOP OF WEIR AT EL. 4.4'0 CD 0 U_0~g C)o U C> to0 ,0 t C) a.-~I 2.00 -r-c C002 C003 S T 1 4.7.35m 7.35m I Looking North n 0 a: 0L N LCZ LLtJ CO Q-Un 0 *S .l E S.5.*.a*_Cu a)ci c Q C.~S 0 a)a0 FR 0400: FOREBAY Survey Unit 6, Concrete Weir Forebay Side Direct Points # C001 -C005 0 0 0 0 C-0 0 0 a)0 U.O E z 0>5>5 60 a)2!:3 ,)D U)0 u2 0_U)76 C iL 0 N 0 , El C 0 16 I-0 P 1i..>1 2), CO Top of Weir!- -i I _ .-----I 'Y l' X i I 4)o 9 0 Q C4 0 0 U.BOm I_G."/r Onl_ .,t^;., .- ---- --' j >-w I v u .T S i-1 06.70m j RI Q P I i I--Cool C002 0 C003@ C004@ C005@Looking North-ly x w V U i T S R Q P r-Concrete Weir, Forebay Side = 70 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within Water/Demo Bounds)

Tr C 0)E a, LC~>.Q.t.-* E 0 C., al)0 E*-E 0 E 0 Survey FR 0400: FOREBAY Unit 6, Concrete Weir Forebay Side Survey Scans # COO1 -C030 C)c)C 0 0 L).0 a)0 IL E z C)ZC, a)M C)>(U)U)0 2 H in 0 (U ,, N L)0-o C.), CO 0 0 V.o Ut* o)o _o C 0 Y x W V U T S R Q P Cool I C003 C005 C007 C009 Coll C013 C0iS C017 C019 C021 C023 C025 6 C028 IC030 C002 C004 C006 C008 Colo C012 C014 C016 C018 C020 C022 C024 C02ClTOP OF WEIR AT EL 4A APPROX WATER LINE @ El. 2 \Looking North Scan Grids are 1 m wide and span from waters edge thru top of weir.Concrete Weir, Forebay Side = 70 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within Water/Demo Bounds)

Maine Yankee

• a ..., Map ID #: FRO400-06d Decommissioning Team Aine Yankee Decommissiong Project Survey Form Revised: 12-1-03 Survey Type: E Characterization E Turnover U Final Status Survey Survey Area Name: Forebay Concrete FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Face ISOCS Spot Check Point # C004 8.50m_ _ .I-. 2.7 5r I" *a 4.25rn*2.7 5In --i._____I D1f1user Inloke Vertical Construction Joint C_Constiructlion Jointl OED. 9'"*"Steel Beam Construction Joint §P ElI' _iiii 4 2.00r i Id..t C004_____________

£Looking South FR-0400-06, Revision 0 Page 15 of 31 Maine Yankee AanYakeDcmisoigPoetSry rmMap ID #: FR040-6e Decommissioning Team laine Yankee Decommissioning Project SurveyI oruui Revised: 12-2-03 Survey Type: O Characterization El Turnover U Final Status Survey I Survey Area Name: Forebay Concrete FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Face Direct Points # C006 -C007 4 * ....-..l Costruction Joint 0 El. 9* C006 C007@Constructionx Joint C EL I'L a.Looking South FR-0400-06, Revision 0 Page 16 of 31 Intake Structure Face= 38 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within Water/Demo Bounds)

Maine Yankee ...Map ID #: FRO400-06f Decommissioning Team AIahIe Yankee Decommissioning Project Surve For Revised: 12-1-03-Survey Type: O Characterization O Turnover U Final Status Survey Survey Area Name: Forebay Concrete FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Face Survey Scans # C031 -C069-_ -- 4-; --- t-Y Diffuser Intake Vertical Construclion Joint_ o u nSteet Beam-SoQCcn3Jrd -nL I.- -- -- -.C031 C032 C0331 C034 C035 C036 C037 C038 C039 C040 C041 IC042 C043 C044 C045 C058 C057 C0561 C055 C054 C053 C052 C051 C050 C049 C048 IC047 C046 LEDGE C059 C060 C061 C062 C063 C064 C065 C066 CC67 Construction Jcint -El.1-'= Grids do not exist Looking South C068 C069 LEDGE Scan Grids are Im x I m Intake Structure Face= 38 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within Water/Demo Bounds)FR-0400-06, Revision 0 r.agc 17 uI 3 I FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Walls ISOCS Spot Check Points # C005 -C006 M W.O 51.70,. 0--4.85 7.32,. --9 9.62 M 477'IT 14.77_ _ _ I _ _ _ _D WEST RETAINING WALL (Looking West)

FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Walls Direct Points # C008-C015'rticol WEST RETAINING WALL (Looking West)co:I .* -.; U 7'- __.--1-. _ ,7j, -._. ..,_.-i WEST RETAINING WALL (Looking West)West Retaining Wall= 130 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within Water/Demo Bounds)

FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Walls Survey Scans # C070 -C101 0 0.4-51.11.8 10 11 12 WEST RETAINING WALL (Looking West)Scan Grids are 3m x Im West Retaining Wall= 130 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within Water/Demo Bounds)

FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Walls Q ISOCS Spot Check Points # C007 -C008 OO EAST RETANING WALL (L°°kin East)

FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Walls Direct Points # C016 -C023 0 0>*TYP.EAST REMNING WALL (Looking Eost).: .... .. ._... ': me,> .. .-..u; .i ---.Verticol Joint, I TYP. \!EAST RUJNING WALL (Looking Cost)East Retaining Wall= 204 sq-m (Above Water)SA= 336 sq-m (Total Above Water for SU 6)

FR 0400: FOREBAY Survey Unit 6, Concrete Intake Structure, Walls Survey Scans # C102 -C126 0 0 T0 c 1.4> en O.6 M O X O X 1= t-56.20rr 28 27 EAST RETAINING WALL (Loos East)East Retaining Wall= 98 sq-m (Within Water/Demo Bounds)SA= 336 sq-m (Total SU6 Area within WaterlDemo Bounds)Grids are 3m x I m Attachment 2 Survey Unit Instrumentation FR-0400-06, Revision 0 Page 24 of 31 TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN l Probe S/N (type)2488 148932 (43-68)2489 148934 (43-68)2489 148937 (43-68)2490 148937 (43-68)2490 148117 (43-68)2619 148117 (43-68)ISOCS SIN Probe S/N (type)7607 N/A TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL, AND DESIGN DCGLENIC Detector 43-68 Scan MDC 1,832 (dpm/100 cm 2) LTP Table 5-6 DCGL 21,0 (dpm/100 cm 2) 18,000 Investigation Level 19,536 Alarm Setpoint (- DCGL Plus (dpm/100 cm 2) Ambient Background)

Design DCGLE^1c (dpm I00 cm 2) 37,440 from Release Record Table I Detector ISOCS SpcanMDC 2.5E305 (Co-60)FR-0400-06, Revision 0 Page 25 of 31 Attachment 3 Investigation Table (No Investigations Required)FR-0400-06, Revision 0 Page 26 of 31 Attachment 4 Statistical Data FR-0400-06, Revision 0 Page 27 of 31 Survey Package FR-0400 Unit 6 Surface Sign Test Summary Eva! lt r iln ' t aI s.,.. .ommentr s me a'Survey Package: FR-0400 Forebay Survey Unit: 06 Evaluator:

GP DCGLw: 18,000 DCGL,,,: 37,440 LBGR: 9,000 Sigma: 220 Type I error: 0.05 Type II error: 0.05 Total Instrument Efficiency:

13.0%Detector Area (cm 2): 126 Concrete Choosing 'N/A' sets material Material Type: Unpainted background to "0" Z.<: 1.645 Z,.P1.645 Sign p: 0.99865 Calculated Relative Shift: 40.9 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift >3 N-Value: 11 N-Value+20%:

14:- <:<'tatci' D Va orn ; >,-1 -Commen ;i Number of Samples: 23 Median: 300 Mean: 605 Net Static Data Standard Deviation:

1,100 Total Standard Deviation:

1,114 SRSS Maximum: 3,853_________

_ .am m en : i Adjusted N Value: 23 S+ Value: 23 Critical Value: 15-~ -. .r a .-Sufficient samples collected:

Pass Maximum value <DCGL,: .Pass Median value cDCGLW: Pass Mean value <DCGL,: Pass Maximum value <DCGLI,,:

Pass Total Standard Deviation

<=Sigma: Investigate See section E of the Release Record Sign test results: -.Pass The survey unit passes all conditions:

Investigate SU-6 passes FR-0400-Su6-SurfacSign FR-0400-06, Revision 0 Page 28 of 31 11130104 11:02 AM FR-0400 SU-6 Quantile Plot ('I E 0 0 CD I-E._*.-.5 0W 4500 4000 3500 3000 2500 2000 1500 1000 500 0-500-1000**

• _

• 5 -V) + I i)s 25J 50O 7- 5 1)0.Activity (dpm/100 cm2)-Median (dpm/1 00 cm2)0 0> ^GJ f...Q~0 0 o 0 M a 0 LZ..Percent Page/Date/Time Database Variable One-Sample T-Test Report 2 11/30/04 12:26:41 PM C:\Program Files\NCSS97\FR0400SU6.S0 C2 Plots Section Histogram of FR-0400, SU-6 E (0 0.0 3E z Activity (dpm/100 cm2)FR-0400-06, Revision 0 Page 30 of 31 One-Sample T-Test Power Analysis Page/Date/Time 2 10/27/04 11:28:45 AM Chart Section L.0 0-1.0-0.8-0.6 0.4 0.2-0.0 0 Retrospective Power Curve..I Il I I* g* l\ I I X I I I , .\ , I ' \ 'I' ' I' I \ I I I X Il I' ' I \I -- I I I 5000 10600 15600 Survey Unit Mean (dpm/100 cm2)20600 FR-0400-06, Revision 0 Page31 of 31