ML043500274
| ML043500274 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 12/07/2004 |
| From: | Pillsbury G, Randall D Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FB-0800-01, Rev 0 | |
| Download: ML043500274 (19) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-0800 FUEL OIL STORAGE BUILDING SURVEY UNIT 1 Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FB-0800 FUEL OIL STORAGE BUILDING SURVEY UNIT I A. SURVEY UNIT DESCRIPTION FB-0800, Fuel Oil Storage Building, is the post demolition structural remnant of a concrete structure. The survey area is comprised of one survey unit and consists of the remaining concrete floor slab of the building. The rectangular slab was located inside a 3-foot deep excavation. The outer dimensions of the rectangular area of the slab measures approximately 250 m2 , however, some portions of the slab were removed during demolition, leaving approximately 126 m2 that were inappropriate for beta survey. This part of the building footprint will be surveyed as part of the FR0200 survey package.
The survey unit is located at 407,285 N and 624,090 E using the Maine State Coordinate System (West Zone) NAD 1927 as shown on map FBO800-01 (Attachment 1). While the survey area was located inside the Industrial Area of the site, it was outside of the plant's radiologically Restricted Area (RA). The Survey Unit area is shown in relation to other major site structures in map FBO800-01. All maps referenced in this release record are provided in Attachment 1, unless otherwise noted. The survey unit's total area is approximately 124 m2 .
B. SURVEY UNIT DESIGN INFORMATION FB-0800 Survey Unit I was designated a Class 3 survey unit per the LTP (Table 5-1 B).
Since the building was constructed just prior to decommissioning and only held clean fuel oil, it had a very low probability to contain any plant-derived residual contamination. No plant-derived radioactive materials were stored or used in the building.
The survey unit design parameters are shown in Table 1. Given a relative shift of 3.0, it was determined that 14 direct measurements were required for the Sign Test. Measurement locations were randomly determined and are illustrated on the map FBO800-02 (Attachment 1). All direct measurements consisted of 1-minute 43-68 gas-flow proportional counter scaler counts, obtained at the required locations.
A 1% to 10% scan coverage of the area was required.' Scan areas were typically 1 m2 square grids, as shown on survey maps FBO800-03 (Attachment 1). The total scan area was approximately 16 m2 (13% area coverage).
LTP Table 5-3 FB-0800-01, Revision 0 Page 2 of 19
Background values were established for the instrument probe based on ambient background values in the survey unit and previously established material backgrounds. The background value, list in Table 1, was 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.
TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria l Basis Based on area dimensions Area 124 m2 less the portions to be surveyed as part of FR0200.
Based on an adjusted LBGR Number of Direct of 17,106 dpm/100 cm2, Measurements Required Minimum of 14 sigma 2 of 298 dpm/100 cm2 and relative shift of 3.0.
Type I = Type II= 0.05 Sample Area N/A Class 3 Area Sample Grid Spacing N/A Class 3 Area Scan Grid Area I m 2 grids used Class 3 Area Area Factor N/A Class 3 Area Scan Survey Area 16 m2 Class 3 area-13%
Background e ° . a : - .- :
43-68 Direct and Scan 2607 dpm/lOO cm 2 Ambient and Material (flat surfaces) 2607d________AmbentandMatria Scan Investigation Level Background plus DCGL. EC 009-OI(Reference 1)
DCGL 18,000 dpm/100 cm2 LTP Revision 3 Design DCGLEMC N/A Class 3 Area C. SURVEY RESULTS As required, 14 direct measurements were made in Survey Unit 1. All direct measurements were less than the DCGL. The results are presented in Table 2 below.
No verified alarms occurred while scanning the concrete surface. Therefore, no investigations were required.
2 Design sigma from LTP Rev. 3, Table 5-1 B, B0800 Fuel Oil Storage Building FB-0800-01, Revision 0 Page 3 of 19
TABLE 2 DIRECT MEASUREMENTS Sample Number Gross Activit Net Activity (dpm/100 cm 2) (dpm/00 cm2)
FB-0800-1-COOI 2,717 110 FB-0800-1-C002 2,955 348 FB-0800-1-C003 2,875 269 FB-0800-1-C004 3,101 495 FB-0800-1-CO05 3,065 458 FB-0800-1-C006 2,882 275 FB-0800-1-C007 3,150 543 FB-0800-1-C008 2,814 208 FB-0800-1-C009 3,059 452 FB-0800-1-C010 2,717 110 FB-0800-1-CO1 1 2,845 238 FB-0800-1-CO12 3,010 403 FB-0800-1-C013 3,028 421 FB-0800-1-C014 2,943 336 Mean 2,940 333 Median 2,949 342 Standard Deviation 137 137 l Range 2,717 -3,150 110 - 543 D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS No verified alarms were received during scanning; therefore, no investigations wvere required.
E. SURVEY UNIT DATA ASSESSMENT An analysis of the direct sample results, including the mean, median, standard deviation, and sample result range are provided in Table 2. Both the mean and the median activities were less than the DCGL. The maximum direct measurement result, without subtracting background, was 543 dpm/I 00 cm 2 .
When the background value is subtracted from the sample results for the survey unit, the result is a net mean value of 333 dpm/100 cm2 . This would be equivalent to an annual dose rate of 0.0056 mrem/y3 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) to be 0.301 mremly.
FB-0800-01, Revision 0 Page 4 of 19
F. ADDITIONAL DATA EVALUATION Attachment 4 provides additional data evaluation associated with Survey Unit 1, including relevant statistical informnation. 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.
Table 2 presents the direct measurement results with the survey unit specific background subtracted (i.e., the "Net Activity" column). 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 wvell as a listing of the key release criteria. As is shown in the table, all of the key release criteria were clearly satisfied for the FSS of this survey unit.
- 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 activity (543 dpm/l 00 cm2 at location C007) is well below the DCGL of 18,000 dpm/I00 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 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.
FB-0800-01, Revision 0 Page S of 19
G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON TILE 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 less than the design sigma. Thus, no additional measurements were required.
H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit I was designed, performed and evaluated in late 2004. The design was performed to the criteria of the LTP, Revision 3, as amended (Reference 2, 3, 4 and 5).
There were no subsequent LTP changes with potential impact to this survey unit.
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 direct measurements were less than the DCGL of l 8,000-dpm/l 00 cm2 .
A Sign Test Summary analysis demonstrated that the Sign Test criteria were satisfied. The direct measurement sigma was determined to be less than that used for design, thus indicating that a sufficient number of samples was taken.
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 no outliers.
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.
It is concluded that FBO800 Survey Unit I meets the release criteria of IOCFR20.1402 and the State of Maine enhanced criteria.
FB-0800-01, Revision 0 Page 6 of 19
J. REFERENCES
- 1. Maine Yankee Engineering Calculation, EC-009-01
- 2. Maine Yankee License Termination Plan, Revision 3, Maine Yankee letter to the NRC, MN-02-048, dated October 15, 2002
- 3. Maine Yankee License Termination Plan, Revision 3 Addenda, Maine Yankee letter to the NRC, MN-02-061, dated November 26, 2002
- 5. Issuance of License Amendment No. 170, (Related to Activated Concrete Submittal),
NRC letter to Maine Yankee, dated February 18, 2004 FB-0800-01, Revision 0 Page 7 of 19
Attachment 1 Survey Unit Maps FB-0800-01, Revision 0 Page 8 of 19
Decommissionrink eTeam Maine Yankee Decommissioning Project Survey MapM ID
- FIBOO-O Survey Type: [Characterization OTurnover EFInat Status Survey [8ackground Ausesrment Survey Area Name: Fuel Oil Slorage Buliding I RT 12/6/04 FBO800 SUl Site Fuel Oil Storage Buidling FBO800 SU1 = 124.4 m2 FB-0800-01, Revision 0 Page 9 of 19
Decomaissionin Team I Maine Yankee Decommissioning Project Survey Map ID
- FBO800-02 Sursey Type OCh.ract.rizatlon OTurno.*r EFinal St.tus Sur.ey OBeckground Assessment Survey Area Name: Fuel Oil Storage Building F RJT 122/6/04 FBO800 SUl Direct Measurement Locat ions 0 = Direct Measurement Locations
_/_/_/_M = Areas that are not port of survey unit 1
to a)
E U,
x 0
4 5 6 FB-0800-01, Revision 0 x axis (meters)
Page 1O of 19
Maine Yankee Decommissionin Team l Maine Yankee Decommissioning -
Project Survey Map IMap ID
- FBO800-03 Sursey Type: QCharacterizatlon OTurnover NFInal Status Survey O39ackground AssessmenT Fsurvey Area Name: Fuel Oil Storage Building I RJT 12/6/04 FBO800 SU1 Scan Locations O - 1m2 Scan Grid Locations
- Areas that are not part of survey unit 1
0 4._
x 0I FB-0800-01, Revision 0 Page II of 19
Attachment 2 Survey Unit Instrumentation FB-0800-01, Revision 0 Page 12 of 19
TABLE 2-1 INSTRUMENT INFORMATION I E-600 S/N Probe SIN (type) 2618 149073 (43-68) 2491 148939 (43-68)
TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL 43-68 Detector Fia68 Scan MDC 1,832 (dpm/I00 cm 2 ) LTP Table 5-6 DCGL 18,000 (dpm/100 cm2 )
Investigation Level 20,604 (Alarm Setpoint) (- DCGL plus BKG)
(dprn/1 00 CM2) _ _ _ _ _ _ _ _ _ _ _ _
FB-0800-01, Revision 0 Page 13 of 19
Attachment 3 Investigation Table (None Required)
FB-0800-01, Revision 0 Page 14 of 19
Attachment 4 Statistical Data FB-0800-01, Revision 0 Page 15 of 19
Survey Package FBO800 Unit 1 Surface Sign Test Summary Evaluation li ut.Val Os ___.:- ,-
Survey Package: FBO800 Fuel Oil Storage Building Slab Survey Unit: 01 Evaluator: DR DCGLw: 18,000 DCGLem: 18,000 N/A-class 3 unit LBGR: 17,106 Sigma: 298 Type I error: 0.05 Type II error: 0.05 Total Instrument Efficiency: 13.0%
2 Detector Area (cm): 126 Concrete Choosing 'N/A' sets material Material Type: Unpainted background to "0" Cj6 if d ai-6^-Jes me '- li,.-- ;>' d, a;i-.<-;
dl;i Crm t V>i Z.<: 1.645 Z.p: 1.645 Sign p: 0.99865 Calculated Relative Shift: 3.0 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift >3 N-Value: 11 N-Value+20%: 14
.gStaticData, ta ornment Number of Samples: 14 Median: 344 Mean: 335 Net Static Data Standard Deviation: 137 Total Standard Deviation: 242 SRSS Maximum: 546
. SlgonTeist g Resuits Dot JL2 n Adjusted N Value: 14 S+ Value: 14 Critical Value: 10 on - K Com~ment Sufficient samples collected: Pass Maximum value <DCGL: Pass Median value <DCGL,: Pass Mean value <DCGL v: Pass Maximum value <DCGL,,,: Pass Total Standard Deviation <=Sigma: :Pass Sign test results: Pass TheSH<
sr uit. pasFssallS y atuso'ndtions Pa U Passe The survey unit passes all conditions:l Pass SU Passes F60800-SUI-SurfaceSign FB-0800-01, Revision 0 12/1104 9:46 AM Page 16 of 19
FB-0800 SU-1 Quantile Plot 600 N 500 E *
- 0 0
400 0
- Activity (dpm/100 cm2)
WCD 1'
- c Ir I _.E 300 N0 C.
O 0 * - Median (dpm/100 o u 0
200 cm2) i" 450 . .
100 0
0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 12/1/04 10:15:35 AM Database Variable C2 Plots Section Histogram of FB-0800. SU-1 10 C,
a.
E 0
.0 E
z Activity (dpm100 cm2)
FB-0800-01, Revision 0 Page 18 of 19
One-Sample T-Test Power Analysis Page/Date/Time 2 12/1/04 10:16:16 AM Chart Section Retrospective Power Curve I I.0_ .-- .- ---
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- 0. l l l 0 50b0 10600 1560o 206oo Survey Unit Mean (dpm/100 cm2)
FB-0800-01, Revision 0 Page 19 of 19