ML043640300

Maine Yankee Final Status Survey Release Record FR-0400 Forebay Survey Unit 5

ML043640300
Person / Time
Site:	Maine Yankee
Issue date:	12/22/2004
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-0400-05, Rev 0
Download: ML043640300 (26)

Text

MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0400 FOREBAY SURVEY UNIT 5 Prepared By: (9 , A Date://-3 -e r'FSS Engineer -Signature.Date: 'i:C ' .3 t Reviewed By: (Reviewed By: liIniependent Reviewer -Signature rib 7 CQ7,a,'-re Date: II/z to Approved By: Date: I //3/, <Suiipen tendentS<

-ignpture Plfne 6 Nam / I Pr~nted Name /7 Date: .Approved By: ,,4,O -intr riSS, MOl- Signature Printed Name MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0400 FOREBAY SURVEY UNIT 5 A. SURVEY UNIT DESCRIPTION Survey Unit 5 is located within Survey Area FR-0400, the Forebay. The Forebay is located south of the radiologically Restricted Area of the site at coordinates 407,000 N and 623,600 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 effluent.

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 wvalls 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 .vest 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 5 consists of the South floor of the Forebay basin, bounded to the North by Survey Unit 4. The survey unit is bounded to the West by Survey Unit 7 (at the toe of the Forebay dike's slope) and to the East by Survey Unit 8. Its southern boundary is the intake structure of the diffuser.

Survey Unit 5 consists of rock and sediment media. The Survey Unit has a surface area of approximately 1,410 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.

Given the high probability of residual contamination, the Forebay was classified as Class 1.Revision 3 of the Maine Yankee License Termnination 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.LTP, Revision 3 refers to the LTP submitted in October 2002 (Reference

1) 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-0400-05, Revision 0 Page 2 of 26 A technical basis document outlining the proposed Forebay survey plan was submitted to the NRC prior to commencing the surveys (Reference 4). The Technical Basis document described and established the technical sufficiency of the underwater in sidl and Nal(TI)techniques for use in the Forebay. Attachment 2H of the LTP describes the characterization data obtained from the Forebay. This data formed the basis for the Forebay survey design.The survey unit design parameters are shown in Table 1. This table reflects the current design parameters, some of which have been revised since the survey was completed as discussed in Section H. The survey unit design was not based on sigma and relative shift (per Reference 4). A minimum number of 50 direct samples were planned for the Survey Unit. This number was determined based on the Survey Unit size and was selected to attain a design area factor of 10 per the Forebay Technical Basis Document.

Since the data assessment is unitized, the Sign Test Summary in Attachment 4 uses a value of sigma obtained from volumetric samples from FR 0400 Survey Unit 1. Direct measurement locations were determined using a random start point and a square grid. These locations are presented on survey map FR 0400-5a in Attachment

1. The direct measurements consisted of in situ measurements obtained with the ISOCS detector.The survey unit design also included 179 individual scan grids of 3 m by 3 m (see map FRO400-5b in Attachment 1). Each grid was scanned using a Nal detector with an alarm setpoint established at background plus 4,000 c/m. This scan survey ensured there were no unidentified areas exceeding approximately 1/2 of the DCGLEN1C limit. The survey instruments used, their MDC value, and alarm setpoints are provided in Attachment 2.In order to establish the alarm setpoint for the E-600 used for scanning, the underwater background of the Forebay must be known. Due to the varied materials of composition and the bottom topography of the Forebay, background can only be approximated.

As such, two approaches were used to estimate a background for this survey. The first approach consisted of an analytical model based compiled volumetric sample data from several types of Forebay samples. The next approach consisted of an evaluation of actual Forebay scan data. Based on an evaluation of the results from the two approaches, the generic background value for the Forebay was set at 16,000 cpm. Adding 4,000 cpm to this value provided an alarm setpoint of 20,000 cpm which is equivalent to a scan MDC of approximately 180,000 dpmllO00 cm 2.FR-0400-05, Revision 0 Page 3 of 26 TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Critcria Basis Area 1,41 0 ml Number of Direct 50 Selected based on design basis of Measurements Required Forebay Sample Area 28.2 mZ 1,410 / 50 samples Sample Grid Spacing 5.25 m (28.2)'2 Area Factor 10 (conservative)

Design value from the Forebay Technical Basis Document Scan Grid Survey Area 9 mZ Background

.<. §1 ' ' 'A;..- ., x SSPA-3 (scan) 16,000 cpm DI 6-150 ISOCS (direct) N/A Provides a scan MDC of Scan Investigation Level Background

+ 4,000 cpm approximately 180,000 dpm/100 cm 2 See Table 2-2 Source: Forebay Technical Basis Document DCGL' 1 .62E6 pCi/mL Forebay Technical Basis Document DCGLEMC 1.62E7 pCi/M 2 Area Factor x DCGL C. SURVEY RESULTS As required, 50 direct measurements were obtained.

The direct measurement data are presented in Table 2. The ISOCS measurements are presented in units of pCi/M 2.Six direct measurement results were greater than the DCGL, but less than the DCGLENc. These measurements were investigated as discussed in Section D.The survey was designed for 179 scan grids. Three grids could not be scanned due to the rock ledge being present in the grids. The scan process identified 48 grid locations for investigation.

A total of 51 grids received investigation measurements.

The grids are indicated on survey map XR 0400-05a and XR 0400-05b of Attachment

1. The investigation results are discussed in Section D.2 162E6 pCi1M2 = 36,000 dpmf100 cm 2 x P x 0,000cn2 2.22dpm m2 FR-0400-05, Revision 0 Page 4 of 26 TABLE 2 DIRECT MEASUREMENTS Cs-137 Co-60 Unitized Value of Sample Number (pCi/m 2) (pCi/n 2) Unity Rule lFRO400051ROOI 4.19E+05 + 25.85% 9.27E+05 + 7.28% 0.831 FR0400051R002 2.13E+05 + 31.90% 5.OOE+05 + 7.99% 0.440 FR0400051R003 2.09E+05+24.77%

1.IIE-E+05 15.24% 0.197 FRO40005 I R004 2.19E+05 + 26.41% 3.44E+04 +37.05% 0.156 FR0400051ROOS 2.25E+06 + 35.91% 5.63E+05 + 22.87% 1.735 FR0400051R006 2.51 E+05 + 34.71% 1.80E+05 + 15.74 0.266 FR0400051R007 O.OOE+00 <3.47E+04 0.021 FR0400051R008 4.07E+04 +38.00% 2.04E+04 + 27.03% 0.038 FR0400051RO09 O.OOE+O0 5.88E+05 + 12.12% 0.363 FRO400051RO10 4.05E+05 + 54.68% 9.76E+05 + 8.52% 0.852 FR0400051RO1

_ 3.58E+04+49.87%

<1.50E+04 0.031 FR0400051R012 5.39E+04+43.38%

<1.90E+04 0.045 FR0400051R013 O.OOE+00 <7.61E+04 0.047 FR0400051R014 1.97E+06 + 86.34% 4.50E+05 + 43.91% 1.496 FR0400051ROI5 1.55E+07 + 13.56% 2.85E+05 + 43.32% 9.738 FRO400051RO16 7,67E+04 + 53.67% 2.20E+04 + 42.67% 0.061 FRO400051RO17 5.35E+04 +42.84% , 9.97E+03 + 52.68% 0.039 FR0400051RO18 8.61E+06 +29.99% <5.35E+05 5.643 FR0400051R019 0.OOE+00 <5.27E+05 0.325 FR0400051R020 2.63E+04+61.19%

<1.3 1E+04 0.024 FR0400051R021 8.09E+04+

18.74% 1.20E+04 + 24.95% 0.057 FR040005IR022 0.OOE+00 <4.77E+05 0.294 FR0400051R023 O.OOE+00 1.41E+05 + 32.93% 0.087 FR0400051R024 2.29E+06 + 49.32% 3.57E+05 + 59.01% 1.633 FR0400051R025 6.90E+04+

100.24% 4.68E+05+9.36%

0.331 FR0400051R026 0.OOE+00 2.21E+05+

19.93% 0.136 FR0400051R027 O.OOE+00 <4.39E+05 0.271 FR0400051R028 O.OOE+00 4.24E+05 + 9.89% 0.261 FR0400051R029 O.OOE+00 1.05E+05 + 29.52% 0.065 FR0400051R030 O.OOE+00 <6.3 1E+04 0.039 FR0400051R031 O.OOE+00 3.51E+05+11.92%

0.217 FR040005IR032 0.OOE+00 3.19E+05 + 10.57% 0.197 FR0400051R033 0.OOE+00 1.79E+05+

13.55% 0.111 FR0400051R034 0.OOE+00 6.05E+05_+

19.64% 0.374 FR0400051R035 O.OOE+00 1.93E+05 + 12.52% 0.119 FR0400051R036 0.OOE+00 7.05E+05+

7.20% 0.435 FR0400051R037 0.OOE+00 3.25E+05 + 10.93% 0.200 FR0400051R038 0.OOE+00 4.20E+05 + 12.89% 0.259 FR0400051R039 O.OOE+00 2.21E+05 + 11.78% 0.136 FR0400051R040 0.OOE+00 3.26E+05 + 9.70% 0.201 FR0400051R041 5.59E+04 +45.87% 5.20E+05 + 7.82% 0.355 FR-0400-05, Revision 0 Page 5 of 26 FR0400051R042 0.OOE+00 9.15E+04 + 21.95% 0.056 FR0400051 R043 O.OOE+00 3.74E+05 + 9.36% 0.231 FR0400051 R044 0.OOE+00 1 .98E+05 + 12.67% 0.122 FR0400051R045 O.OOE+00 3.32E+05+

11.06% 0.205 FR040005 I R046 O.OOE+00 6.94E+05 +8.56% 0.428 FR040005 1 R047 O.OOE+00 7.92E+05 + 7.53% 0.489 FR0400051R048 0.OOE+00 4.15E+05 + 9.84% 0.256 FR0400051R049 O.OOE+00 1.81E+06 + 6.69% 1.118 FR0400051R050 O.OOE+00 6.71E+05 + 9.03% 0.414 Mean N/A N/A T 0.628 Median N/A N/A 0.224 Standard Deviation N/A N/A l 1.558 Range N/A N/A 0.021-9.738

"<" indicates MDA value for non-detect Co-60 results.D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS The scan process identified 48 grid locations for investigation.

These grids, plus three additional, were evaluated using investigation package XR0400-05.

All investigations consisted of in situ measurements with the ISOCS detector.

The investigation results were combined with the 6 direct measurement results, which were greater than the DCGL, for comparison with the DCGLENIC criteria.

The aggregate results were determined to be in**compliance wvith the Elevated Measurement Comparison limit. This assessment is included as Attachment 3 (Table 3-1).E. SURVEY UNIT DATA ASSESSMENT RESULTS An analysis of the direct sample measurement results, including the mean, median, standard deviation, and sample result range, are provided in Table 2. Positively detected values are bolded in the table. Since Cobalt-60 is the primary radionuclide ofconcern, non-detect values were assumed present at the MDA. Non-detected values for Cesium-I 37 were assumed not to be present. However, some Cs-I 37 values wvere reported positive with high uncertainties that were less than the post-priori MDA. These have been included in Table 2 and 3-1 as positive results. The column to the right is the DCGL unity column. The mean value of this column indicates that the direct samples were at 62.8% of the DCGL limit. This is equivalent to an annual dose rate of 1.1 7E-2 mrem 3.The maximum direct sample result was equivalent to 97.4% of the design DCGLEMC. A total of six measurements exceeded the DCGL. These measurements were evaluated and found to be acceptable.

The sample standard deviation is larger than the design sigma, however, no additional measurements were required due to the results of the sign test.Forty-eight SSPA-3 scan alarms were encountered while surveying.

Since the scan grids were 3m x 3m squares, an Area Factor of 35 wvas used. This area factor was also conservatively applied to direct measurements for the EMC comparison since the area extent for the ISOCS measurement geometries is approximately 8 m .The 48 verified alarms, along with three additional grids and the six direct measurements that were above the DCGL, were investigated as shown in Table 3-1 of Attachment 3, and determined to be approximately 93% of the DCGLE1,C, satisfying the EMC criteria.3 This number is calculated by multiplying the mean value for direct measurements (62.8% of the DCGL) by I .87E-2 mrem/y, the dose scenario outcome for the Forebay floor area.FR-0400-05, Revision 0 Page 6 of 26 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 Power Curve.I. 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, several attributes required further evaluation.

As discussed in Section E, the subject release criteria have been satisfied.

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.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 two outliers.4. A Retrospective Power Curve was constructed, based on FSS results. The curve is inconclusive, but based on the Sign Test, the data provides good confidence that the survey unit satisfied the release criteria.G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON TIlE EXTENT OF RESIDUAL ACTIVITY Due to remediation activities which removed the Co-60 containing sediment, the source term appears to have an increased Cs-137 to Co-60 ratio. This was addressed by specifically including the Cs-137 results (positive detects) in the data evaluation.

As stated in the LTP, the Forebay survey was anticipated to be a "limited" survey with"limited" never defined. The intent was to demonstrate adequate remediation of the Forebay source term using the new survey techniques described in the Technical Basis Document.Because Co-60 was the predominant nuclide in terms of both abundance and dose contribution, the measurements focused on detection of Co-60 activity.

Some instances of high Cs-1 37 activity were found in FR-0400 Survey Unit 4 and Survey Unit 5 which challenged the EMC unity calculation.

Had these high Cs-137 values been anticipated, the investigation criterion could have been adjusted to better account for them.FR-0400-05, Revision 0 Page 7 of 26

11. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 5 was designed and performed using the criteria of the approved Forebay Technical Basis Document (Reference

4) and LTP (Revision 3 Addenda).

In order to deal with the initial failure to meet the EMC unity criteria, a change to the DCGL for the Forebay floor from 18,000 dpm/100 cm 2 to 36,000 dpm/100 cm 2 was processed under I OCFR50.59 as allowed by the LTP. The dose remained within the 1 0 mrem/y and 4 mrem/y drinking pathway limits. The annual dose from the Forebay floor with contamination levels at the new DCGL remains very low with a value of 1 .87E-02 mrem/y. No other LTP changes have been made that would affect the survey results or conclusions for this survey unit.J. 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 detennined for the Sign Test in accordance with the LTP. As presented in Table 2, the direct measurements passed the Sign Test.A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied.

The sample standard deviation is larger than the design sigma (which was based on in sit measurement data). No additional measurements were required because the number of samples was increased in the initial design of the survey in order to achieve a higher area factor and the survey unit passed the Sign Test.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 Forebay Technical Basis Document with significant aspects of the design discussed in Section B and Table 1. Scanning resulted in a number of verified alarms (Section C) for evaluation.

Attachment 3 shows the areas identified by verified alarms and provides the results of the investigation actions. The areas under investigation were evaluated using the appropriate area factor. The survey unit was determined to satisfy the elevated measurement comparison unity rule per LTP methodology (approximately 93% of the DCGLEM,,C criteria limit.).It is concluded that FRO400 Survey Unit 5 meets the release criteria of I OCFR20.1402 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, "Forebay Technical Basis Document", MN-03-5 1, dated September 3, 2003 5. Maine Yankee Calculation EC-041-01 6. Maine Yankee Calculation EC-003-04 FR-0400-05, Revision 0 Page 8 of 26 Attachment 1 Survey Unit Maps FR-0400-05, Revision 0 Page 9 of 26 Maine Yankee Map ID #: FR 0400 SITE Decommissioning Team I rni Revised: 11-,03 Survey Type: El Remediation E Turnover E 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 0 8 0 z n z 0 z 8 z I z SCALE 0...H--Hi I+ +, .400 800 MN 1200 Note: Grid based on Maine State Coordinate System (West Zone) NAD 1927 FR-0400-05, Revision 0 Page IO of 26 Maine Yankee Aliz akeDcmisinn rjc uv oiIMap ID #: FR 0400-5a Decommissioning Team Maine Yankee Decommissioning Project Survey Form Revised: 11-04-03 Survey Type: 0 Characterization EO Turnover I Final Status Survey Survey Area Name: Forebay Floor-FR 0400: FOREBAY Survey Unit 5, South End Forebay Floor Direct Points R001 -R050"I DJFFUSIR WNAXE STRUCTUR*R041*R033*RO32 ,RO29 a R026 R023*R028 b R022*R2 g,24 * *R017 OR021 I*RO1 B OR016 fl 5 OR013*R009)12 *OR03 4-t OR0085 ~OR00*ROI 4 N LECEND Rip-Rap Extents (Forebay Bottom).... _.- Concrete...........

Ledge 5.25m (L) Square Grid OROR 6 Direct Point Location FR-0400-05, Revision 0 Page II of 26 L = 5.25, N = 50 SA = 1410 sq-n Scale V1-=50' Maine Yankee M aineYne eomsinn rjc uvyFrnMap ID #: FR 0400-5b Decommissioning Team Maine Yankee DecomIissioning Project Survey For l Revised: 11-10-03 Survey Type: E Characterization 7 Turnover X Final Status Survey I Survey Area Name: Forebay Floor FR 0400: FOREBAY Survey Unit 5, South End Forebay Floor Survey Scans R051 -R229 DIFFUSER INTAKE STRUCTURE LEGEND-_ --- Rip-Rap Extents (Forebay Bottom)ORAPHC Vi~t* -m 4x Concrete..............

Ledge 3m Square Grid R151 Survey Scan Number N FR-0400-05, Revision 0 Page 12 of 26 SA = 1410 sq-rn Scale : 1"=50' Maine Yanvee. ...Map ID #: XR 0400-05a Decommissioning Team Yanee I ecoi issioriflg Pioject Siiie' Fo i Revised: 11-19-03 Survey Type: E Characterization O Turnover E Final Status Survey Survey Area Name: Forebay Floor XR 0400: FOREBAY Survey Unit 5, South End Forebay Floor Investigation Grids DIFFUSER INTAKE STRUCTVURE

..........

.. 114Z ".-'s°>h0t-4 0 -Investfgadon Grids------..............

R151 LECEND Rip-Rap Extents (Forebay Bottom)Concrete Ledge 3m Square Grid Survey Scan Number O.AP.C &Mt.I .-" -w .WM Y x_ _ N FR-0400-05, Revision 0 Page 13 of 26 SA = 141 0 sq-m Scale: i "=50' Maine Yankee ., ....Map ID #: XR 0400-05b Decommissioning Team AIa -e ' IRevee Decoiiuiissioiug Pioject S ¶eJ' Fo Rised: 11-19-03 Survey Type: C Characterization O Turnover X Final Status Survey Survey Area Name: Forebay Floor XR 0400: FOREBAY Survey Unit 5, South End Forebay Floor Investigation Grids DIFFUSER INTAXE STRUCTURE M- Investigadon Grids..............

R151 LEGEND Rip-Rap Extents (Forebay Bottom)Concrete Ledge 3m Square Grid Survey Scan Number CftP-Ift VCALL=

• Z U_JV FR-0400-05, Revision 0 Page 14 of 26 y 4 SA= 1410 sq-m Scale: 1 "=50' Attachment 2 Survey Unit Instrumentation FR-0400-05, Revision 0 Page 15 of 26 TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN Probe S/N (type) Dsign Scan j 1929 j 726557 (SSPA-3) J 180,000 dpm/1 00 cm'2619 l 2253 (SSPA-3) l 180,000 dpmll00 cm'ISOCS DETECTORS (in situ measurements)

ISOCS Detector MDC (pCilm')7605 See Table 2-2 7607 See Table 2-2 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL, AND DESIGN DCGLEMC Detector SSPA-3 ISOCS Scan MDC 180,000 dpm/100 cm 2 5.0E05 pCi/na_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _(nom inal)DCGL 1.62E6 pCi/m' or 1.62E6 pCi/m' or DCGL 36,000 dpm/100 cm 2 36,000 dpm/100 cm 2 Investigation Level 20,000 cpm A (Alarm Setpoint) (Background

+ 4,000 cpm) N/A D 1.62E7 pCi/lm or 1.62E7 pCi/m' or Design DCGLENIC 360,000 dpm/l 00 cm 2 360,000 dpm/1 00 cm 2 FR-0400-05, Revision 0 Page 16 of 26 Attachment 3 Investigation Table FR-0400-05, Revision 0 Page 17 of 26 TABLE 3-1 INVESTIGATION RESULTS TABLE G Co-60 Cs-137 Cobalt Cesium DCGLEfC GrdCo-60 Cs-137 Minus Minus Grd(pCi/rn

2) (pCi/rn 2) SU Mean SU Mean Activity Activity Comparison

__ __ __ __ __ __ _ _ __ __ __ __ __ _ _ __ __ __ __ __ __ _ (pCi/M2) J (pCi/rn 2) (Unitized) (Unitized)

Fraction 54 9.68E+04 + 50.93% 5.12E+05+48.11%

N/A N/A N/A N/A < DCGL 55 < 1.08E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 58 6.75E+05 + 13.10% 2.95E+05 + 52.50% N/A N/A N/A N/A < DCGL 72 <1.38E+05 6.35E+05 + 31.61% N/A N/A N/A N/A < DCGL 82 7.32E+05 + 13.50% 2.14E+05 + 107.98% N/A N/A N/A N/A < DCGL 88 <1.14E+05 O.OOE+00 N/A N/A N/A N/A < DCGL 89 <1.24E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 102 2.60E+05 + 24.90% 8.72E+05 + 37.97% N/A N/A N/A N/A < DCGL 103 <1.42E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 126 <1.20E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 134 <2.03E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 141 <1.39E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 142 <1.38E+05 0.OO3+00 N/A N/A N/A N/A < DCGL 145 <1.43E+05 O.OOE+00 N/A N/A N/A N/A < DCGL 146 <1.98E+05 O.OOE+00 N/A N/A N/A N/A < DCGL FR-0400-05, Revision 0 Page 18 of26 I o6 s17Co-60 CS17 Cobalt Cesium DCGLEMwC Grid (pCi/M 2) (pCi/rn) SU Mean SU Mean Activity Activity Comparison I _____________(pCi/Mn) (pCi/rn 2) j(Unitized) (Unitized)

Fraction 148 4.04E+05 + 17.79% O.OOE+00 N/A N/A N/A N/A < DCGL 149 <1.47E+05 O.OOE+00 N/A N/A N/A N/A < DCGL 1S0 <1.56E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 151 3.72E+05 + 16.33 % 0.00E+00 N/A N/A N/A N/A < DCGL 153 3.80E+05 + 19.17% 0.OOE+00 N/A N/A N/A N/A < DCGL 156 <1.66E+05 0.OOE+00 N/A N/A N/A N/A < DCGI, 157 1.52E+05 + 30.16% 0.OOE+00 N/A N/A N/A N/A < DCGL 158 <2.21E+05 O.OOE+00 N/A N/A N/A N/A < DCGL 160 7.05E+04 + 51.09% O.OOE+00 N/A N/A N/A N/A < DCGL 161 2.99E+05 + 20.02% O.OOE+00 N/A N/A N/A N/A < DCGL 164 3.68E+05 + 18.36% O.OOE+00 N/A N/A N/A N/A < DCGL 180 3.47E+05 + 19.30% O.OOE+00 N/A N/A N/A N/A < DCGL 186 <5.46E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 187 <4.17E+05 O.OOE+00 N/A N/A N/A N/A < DCGL 191 <1.88E+05 O.OOE+00 N/A N/A N/A N/A < DCGL 195 4.81E+05 + 14.30% O.0OE+00 N/A N/A N/A N/A < DCGI, 196 3.29E+05 + 20.22% O.OOE+00 N/A N/A N/A N/A < DCGL FR-0400-05, Revision 0 Page 19 of 26 Co-60 Cs-137 Coat eim CIrl Co-60 Cs-137 Minus Minus ICbl eim DGV~Grid (pCi/n 2) (pCi/m2) SU Mean SU Mean A Activity Activity Comparison

____________(pCi/rn

2) (pCi/rn 2) (Unitized)

J(Unitized)

Fraction 198 3.50E+05 + 17.66% 0.OOE+0O N/A N/A N/A N/A < DCGL 199 <1.26E+05 0.OOE+00 N/A N/A N/A N/A < DCGL 201 4.34E+05 +/- 17.27% O.OOE+OO N/A N/A N/A N/A < DCGL 202 3.55E+05 + 26.11% 0.OOE+OO N/A N/A N/A N/A < DCGL 203 3.80E+05 + 22.50% 0.OOE+00 N/A N/A N/A N/A < DCGL 204 2.86E+05 + 24.30% 0.OOE+00 N/A N/A N/A N/A < DCGL 207 1.56E+06 +/-10.08% 0.OOE+00 N/A N/A N/A N/A < DCGL 209 1.19E+06 + 10.94% 0.OOE+00 N/A N/A N/A N/A < DCGL 210 3.09E+05 + 15.47% O.OOE+O0 N/A N/A N/A N/A < DCGL 212 4.14E+05+18.45%

O.OOE+00 N/A N/A N/A N/A <DCGL 214 5.35E+05 +/- 8.48% 6.65E+04 + 51.94% N/A N/A N/A N/A < DCGL 216 1.34E+05 + 34.09% O.OOE+00 N/A N/A N/A N/A < DCGL 218 1.91E+06 + 9.64% 0.OOE+O0 1.59E+06 N/A 0.0279 N/A 0.028 219 9.32E+05 + 7.24% O.OOE+00 N/A N/A N/A N/A < DCGL 221 1.46E+06 +/- 11.92% O.OOE+00 N/A N/A N/A N/A < DCGL 226 4.37E+05 +/- 15.34% 1.55E+05+

64.32% N/A N/A N/A N/A <DCGL 227 2.61E+05+

28.96% O.OOE+0O N/A N/A N/A N/A <DCGL FR-0400-05, Revision 0 Page 20 of 26 Co-60 Cs-137 Mi-60 Msn13 Cobalt Cesium DCGLENc Grid (pCI/mn) (pCi/M 2) SU Mean SU Mean Activity Activity Comparison

__ __ __ _ __ __ _ _ __ __ __ _ __ __ _ _ __ __ __ _ __ __ __ _ (pCi/rn 2) (pCi/rn 2) (Unitized) (Unitized)

Fraction 228 1.72E+06 +/- 10.06% 0.OOE+00 1.40E+06 N/A 0.025 N/A 0.025 229 4.73E+06 + 8.88% 0.OOE+00 4.41 E+06 N/A 0.078 N/A 0.078 FRO400051ROOS 5.62E+05 + 22.87% 2.25E+06 + 35.91 % 2.42E+05 2.20E+06 0.004 0.039 0.043 FR0400051R014 4.50E+05 + 43.91 % 1.97E+06 + 86.34% 1.30E+0S 1.92E+06 0.002 0.034 0.036 FRO400051ROIS 2.85E+05 + 43.32% 1.54E+07 + 13.56% -3.50E+04 1.53E+07 0 0.271 0.271 FR0400051 R018 < 5.35E+05 8.61E+06 + 29.99% 2.15E+05 8.56E+06 0.004 0.151 0.154 FR0400051R024 3.57E+05 + 59.0 °% 2.29E+06 + 49.32% 3.70E+04 2.24E+06 0.001 0.039 0.040 FR040005 I R049 1.81E+06 + 6.69% 0.OOE+00 1.49E+06 N/A 0.026 N/A 0.026 SU Mean 0.239 Elevated Areas 0.701 0.701 Total 0.930 _ _NOTES 1. "<" indicates MDA value for non-detect Co-60 results.2. Non-detect Cs-137 results shown as 0.00E+00 as discussed in Section E.3. The Co-60 and Cs-137 mean values were calculated using Table 2 values except that the values for the six directs shown in Table 3-1 were excluded.4. A conservative area factor (AF) of 35 was used based on a scan grid area of 9 m 2.5. The unitized elevated activity was calculated as follows: (Investigation Result -SU Mean) / (AF)DCGL FR-0400-05, Revision 0 Page 21 of 26 Attachment 4 Statistical Data FR-0400-05, Revision 0 Page 22 of 26 Survey Package FRO400 Unit 5 Soil Sign Test Summary-ite' .:4rEvaluation Input Val-ue ,--;A ;- -. -,. -- Cm et vA) i *;Survey Package: FR0400 Forebay Survey Unit: 05 Evaluator:

DR DCGL,,: 1.OOE+00 DCGL,,: 1.OOE+01 LBGR: 5.OOE-01 Sigma: 2.58E-02 (0.31 pCilg 12 pCi/g)Type I error: 0.05 Type II error: 0.05 Nuclide: UNITY Soil Type: N/A.- ??r, -g,,Ca lcitdp as'6 1.3. ' -t<;- 'i0 onn nts7?;ad, Zj: I 1.645 Z1p:.645 Sign p: 0.99865 Calculated Relative Shift: 19.3 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift is >3 N-Value: 11 N-Value+20%:

14 nSriample Data Value )s;< o

• g :, -Comments.

-t, .Number of Samples: 50 Median: 2.24E-01 Mean: 6.28E-01 Net Sample Standard Deviation:

1.56E+00 Total Standard Deviation:

1.56E+00 SRSS Maximum: 9.68E+00*;)Str'>igini eas F.SRits->--<<-- .iisn,--C, onnments!t-f--

Adjusted N Value: 50 S+ Value: 44 Critical Value: 31 Sign test results: Pass Sufficient samples collected:

Pass Maximum value <DCGL,,: Investigate See Sections D&E of Release Record Median value <DCGL,: Pass Mean value <DCGL,,: Pass Maximum value <DCGL.: Pass Total Standard Deviation

<=Sigma: .Investigate See Section F of Release Record Criteria comparison results: Investigate See Section I of Release Record Teu 'u't pas al codfiti o InelStatuse-TeUasise The survey unit passes all cnditions:l

-Invesfigatelh SU passes FRO400-SU5-SoilSign FR-0400-05, Revision 0 12117104 4:01 PM Page 23 of 26 FR-0400 SU-5 Quantile Plot 12 10-r-1-Im-0 , w 0=0 0 0 la a)a-'10m 8 4 I

• Activity (Unitized)

I'-Median (Unitized)]

.,I 4 2 0 0 25 50 75 100 Percent Page/Date/Time Database Variable One-Sample T-Test Report 2 12/21/04 7:10:43 AM C:\Program Files\NCSS97\FRQ400SU5.SO C2 Plots Section Histogram of FR-0400, SU-5 60 aU, E E z 45 30 15 11I n L X -r '_ .1.U ...0.000 2.5006 ' 5.000 ' ' o.500 Activity (unitized)

Io0.b00 FR-0400-05, Revision 0 Page 25 of 26 One-Sample T-Test Power Analysis Page/Date/Time 2 12/21/04 7:11:34 AM Chart Section Retrospective Power Curve 0.8 T 0.6+L_0 0-0.44-0.24-o.o L 0.!II I 5 0'6 0:7 0:8 0o9 1:o Survey Unit Mean (unitized)

FR-0400-05, Revision 0 Page 26 of 26