ML051050083
| ML051050083 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 03/31/2005 |
| From: | Ambrose J, Olsen C, Packer J, Pillsbury G, Tozzie R Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FR-0200-02, Rev 0 | |
| Download: ML051050083 (22) | |
Text
, 1 MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0200 YARD EAST SURVEY UNIT 2 Prepared By: I) Date: 3C - O 5-FSS Engineer - Signature Teff P f\ rMo A Phinted Name Reviewed By: Date: I lo IaSS Slgature Printed Name Reviewved By: Date: 2 0 l~ededtReview - Signature Approved By:rincd atem/§D Printed Name/
Approved By: ___ Date: S
-SS, MOP - Signature Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0200 YARD EAST SURVEY UNIT 2 A. SURVEY UNIT DESCRIPTION The survey unit is essentially land of the Industrial Area of the site that was outside of the current Restricted Area fence. Survey Unit 2 is a land area that has always been outside of the Restricted Area boundary during decommissioning operations. All temporary structures, with exception of the truck monitor and control shack, were removed and all former permanent structures were demolished to at least 3 feet below grade. All blacktop was removed within Survey Unit 2. Survey Unit 2 land encompassed the former Circulating Water Pump House (CWPH) which housed equipment to pump cooling water from the Back River to various heat exchangers in the plant. Negligible amounts of radioactive materials were identified in the CWPH equipment during plant operations and successful FSS was performed of the former structure. A soil sample processing hut used during site characterization formerly resided within the boundary of Survey Unit 2. However, there was no history of the inadvertent spread of contamination associated with the sample processing operations. Most recently, Survey Unit 2 was used as a truck/equipment maintenance area and a truck radiological monitoring station (i.e., clean side waste).
Survey Unit 2 was located at the NE comer of the site Industrial Area yard and is shown in relation to site landmarks on map FRO200-2 Site. Boundaries of Survey Unit 2 are shown on map FRO200-2 REF. The approximate center of survey unit is located at coordinates 624350E & 407540N using the Maine State Coordinate System (West Zone) NAD 1927.
Survey Unit 2 is an area composed mainly of soil and back-fill and is relatively flat.
B. SURVEY UNIT DESIGN INFORMATION The survey unit was designated a Class 3 land survey per the LTP (Table 5-I C). 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 Map FRO200-2a (Attachment 1). Direct measurements (soil samples) were collected from the required locations and analyzed with laboratory gamma spectroscopy instrumentation.
In accordance with the LTP Table 5-3, gamma scans were required for I to 10% of the survey design area. Scan grids typically measuring 2 m by 5 in (10 m2 ) were established in the following areas:
- Along the four meter buffer from the west boundary of the current Restricted Area
- Maintenance area wvest of the former CWPH area
- Along Back River western shoreline The specific scan grids are also depicted on map FRO200-2b.
.FR-0200-02, Revision 0 Page 2 of 22
E-600/SPA-3 instrumentation was used to perform the scan surveys. The survey instruments used are listed by model and serial number in Attachment 2 (Table 2-1). The original 31 scan grids provided a scan area of 310 m 2 , exceeding 10% of the total survey area.
Configuration of the original scan grids is illustrated on FRO200-2b (Attachment 1).
Background values were established based on local scaler values in the survey unit. These background values were used to determine scan alarm set'points and to divide the scan grids into five different background groups. Scan MDCs are listed in Attachment 2 (Table 2-2) and are compared to the DCGL and the investigation level.
TABLE I SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 2,75m 2 No limit for Class 3, based on LTP Area ,752Table 5-2 Based on adjusted LBGR of 3.69 Number of Direct 14 pCi/g, sigma' of 0.17 pCi/g, and a Measurements Required 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 2mx 5m(10 m 2 ) Class 3 Area; < IO m2 Area Factor N/A Class 3 Area Scan Area 310 m2, > 10% (LTP Table 5-3)
Background ; g'Wsr ,. -'; -'-, .YXt.$ i-3gi 7,677 cpm Group 1 9,074 cpm Group 2 SPA-3 (Scan) 10,434 cpm Group 3 11,284 cpm Group 4 9,858 cpm Group 5 Scan Investigation Level 3 Sigma of Background See Table 2-2, Attachment 2 (E-600/SPA-3) plus Background (Reference 6)
DCGL 4.2 pCi/g Cs-137 LTP, Rev. 3, Section 6.7 Design DCGLEMC N/A Class 3 Area LTP Revision 3, Table 5-1 C for Yard East, R0200 FR-0200-02, Revision 0 Page 3 of 22
C. SURVEY RESULTS As required, 14 direct soil measurements were performed in Survey Unit 2 and the results are presented in Table 2. All direct measurements were below 50% of the DCGL. The sample analyses did not identify Co-60 or Cs-137 above the MDAs.
A total of 31 grids were initially scanned using E-600/SPA-3 instrumentation. Five verified scan alarms were received. The investigation results are discussed in Section D. During the scan surveys, approximately 1.5 m2 of surface area could not be scanned. This had no affect on the design since the actual scan area exceeded 10% of the total area.
TABLE 2 DIRECT MEASUREMENTS Sample Location Cs-137 (pCi/g)
FR0200-02-3SOOISS < 8.75E-02 FRO200-02-3S002SS < 6.2 1E-02 FRO200-02-3S003SS < 6.75E-02 FRO200-02-3S004SS < 6.36E-02 FRO200-02-3S005SS < 4.97E-02 FRO200-02-3SO06SS < 5.05E-02 FRO200-02-3S007SS < 5.47E-02 FRO200-02-3S008SS < 4.70E-02 FRO200-02-3S009SS < 4.65E-02 FR0200-02-3SOIOSS < 5.94E-02 FRO200-02-3SOlSS < 3.88E-02 FRO200-02-3S012SS < 4.43E-02 FRO200-02-3S013SS < 9.28E-02 FRO200-02-3S014SS < 4.22E-02 Mean 5.76E-02 Median 5.26E-02 Standard Deviation 1.62E-02 Sample Range 3.88E-02 to 9.28E-02
"<"Indicates MDA value.
Samples were also analyzed for Co-60. All were less than the MDA of 0.1 pCi/g.
FR-0200-02, Revision 0 Page 4 of 22
D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS Soil scans performed with the E-600/SPA-3 identified five scanned grids with verified alarms. All five cpm values ranged within 1.3 to 5.4 percent of the designated alarm set points. Three of the five scan grids with verified alarms (S011, S012, and S019) resided along the buffer to the west fence line between the current Restricted Area and the radiologically unrestricted area. The other two remaining scan grids were situated towards the center of SU2. As a result, investigation package XR0200-02 was wvritten to perform additional scans within the five identified grids and to collect soil samples at the highest scan location within each grid. The grids requiring investigation scans are illustrated on XR0200-2a (Attachment 1). As a result of the investigations, a total of five soil samples were collected.
During the investigation of Survey Unit FR-0200-02, the soil sample results associated with those taken within each of the five grids did not identify Cs-137 nor Co-60 above MDA values.
E. SURVEY UNIT DATA ASSESSMENT An analysis of the direct sample measurement results, including the mean, median, standard deviation, and sample result range, is provided in Table 2. Of the 14 soil samples collected, no samples identified Cs-137 above the MDA values. The identified MDAs are listed in Table 2. The mean and median activities for Cs-137 were also less than 50% of the DCGL.
In addition, Co-60 was not identified in any of the 14 samples.
For illustrative purposes, as indicated in LTP Section 5.9.3, a simplified general retrospective dose estimate can be calculated from the average residual contamination level by subtracting the mean fallout Cs-1 37 value (0.19 pCi/g) 2 for disturbed soil from the survey unit sample mean activity (0.0576 pCi/g). The net result is negative and would equate to an annual dose rate of 0.0 mrem/year. However, for purposes of demonstrating compliance with the radiological criteria for license termination and the enhanced State criteria, background activity was not subtracted from the soil sample analysis activity values.
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.
- 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 were satisfied for the FSS of this survey unit. The sample standard deviation is smaller than the design sigma; therefore no additional samples were required.
2 See attachment E to Maine Yankee Procedure PMP 6.7.8 (Reference 5)
FR-0200-02, Revision 0 Page 5 of 22
- 2. The Quantile Plot was generated from the direct measurement data listed in Table 2. The data set and plot are consistent with expectations for a Class 3 survey unit. All of the measurements are well below the DCGL of 4.2 pCi/g for land outside the restricted area.
- 3. A Histogram Plot was also developed based on the direct measurement data values. This plot shows a log-normal distribution with two outliers.
- 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.
G. CHANGES IN INITIAL SURVEY UNIT ASSUMPTIONS ON EXTENT OF RESIDUAL ACTIVITY The survey was designed as a Class 3 land survey area. A four meter wide portion of the survey area that was directly adjacent to the current Restricted Area boundary was removed to provide a buffer. This buffer area will be surveyed as a Class I area. The FSS results (all direct measurements, initial scan results, and investigation results) were consistent with the Class 3 land survey classification. The direct measurement sample standard deviation was less than the design sigma. Thus, a sufficient number of sample measurements were taken and no additional measurements were required.
H. LTP CHANGES SUBSEQUENT TO SURVEY UNIT FSS The FSS of Survey Unit 2 was designed, performed, and evaluated in the February 2005 to March 2005 time frame. The design was performed to the criteria of the LTP Revision 3 (Reference 1). The only subsequent LTP change modified the Table 6-11 "Contaminated Material DCGL" to reflect an increased Deep Soil DCGL for Co-60 inside the Restricted Area. However, the Deep Soil DCGL change does not apply to this survey unit as the surface soil DCGL for areas outside the restricted area remained unchanged. No subsequent LTP changes with potential impact to this survey unit need to be evaluated.
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 of the direct measurements were less than 50% of the DCGL.
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.
FR-0200-02, Revision 0 Page 6 of 22
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 two outliers.
The scan survey design for this survey unit was developed in accordance with the LTP Revision 3 Addenda (Reference 1) with significant aspects of the design discussed in Section B and Table 1. Scans performed with E-600/SPA-3 instrumentation resulted in a total of five verified alarms. Therefore, five investigations were conducted via package XR0200-02. As a result of the investigations, a total of five additional soil samples were obtained. All sample measurements wvere less than the DCGL of 4.2 pCi/g Cs-137. No detectable Co-60 and/or Cs-137 were identified.
It is concluded that FR-0200 Survey Unit 2 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 and Addenda provided by Maine Yankee letter to the NRC, MN-02-061, dated November 26, 2002
- 2. NRC letter to Maine Yankee, dated February 28, 2003
- 3. Maine Yankee letter to the NRC, MN-03-049, dated September 11, 2003 (LTP Supplement to LTP Revision 3)
- 4. Issuance of License Amendment No. 170, NRC letter to Maine Yankee, dated February 18,2004
- 5. Maine Yankee Procedure PMP 6.7.8, FSS Data Processing and Reporting, Attachment E, Approach for Dealing With Background Radioactivity for Maine Yankee Final Status Surveys
- 6. Maine Yankee Calculation No. EC 009-01 (MY), Instrumentation Selection and MDC Calculation FR-0200-02, Revision 0 Page 7 of 22
Attachment 1 Survey Unit Maps FR-0200-02, Revision 0 Page 8 of 22
(nO cCD 00 W
000 0f 0 00 t EX0 0Li 0a -
0 0)" . =
o 000 0 0 0 0 CDC 0 o 0a00 0--IC CD f z623.000
- C CD N
0
-623,500 C o-n PAR0I a CD (ro~~ 000 625. E (1 rr OAK.
0.
c0CD
_____________ ______ 625.000 C G .
C IN CET 0 03 6260000 en
aine Yankee MMap ID#: FRO200-2 REF Decommissioning Team Maine Yankee DecommissioningProjectSurvey ForM Revised: 2/21/05 Survey Type: 0 Characterization 0 Turnover C Final Status Survey Survey Area Name: Yard East Soil Survey Unit 2 Final Status Survey FRO200 SU2: Yard East Soil Area Reference Map
,#WN62 338 ,.Ea
- l7 407,487.8NI-624,247E L I SU2 Total Surface Area = 2752 m 2
Maine Yankee I Map IDIt FRO200 Decommissioning Team IAlaine Yankee DecommissioningProjectSurve Form Revised: 2121I05 Survey Type: 0 Characterization El Turnover 11 Final Status Survey Survey Area Name: Yard East Soil Survey Unit 2 Final Status Survey FRO200 SU2: Yard East Soil Area Direct Points 001 - 014 l
407,4
-624,:
t 011 ii
/013-I-
ii
-::i
Maine Yankee IMap ID#t FRO200-2b Decommissioning Team IMaine Yankce DecommissioningProjectSurvey Form IRevised: 3/14105 Survey Type: O Characterization O Turnover I Final Status Survey Survey Area Name: Yard East Soil Survey Unit 2 Final Status Survey FRO200 SU2: Yard East Soil Area Survey Scans S001 - S031
' / \ ?///////J I I Z-
/
407,1 407,640.5N r ---- ----
l l li li L Ii
-I-Jj
Maine Yankee IMap ID#FXR0200-2a Decommissioning Team IMaine Yankee DecommissioningProject Survey Form IRevised: 3/14105 Survey Type: W Investigation E Turnover E Final Status Survey I Survey Area Name: Yard East Soil Survey Unit 2 Final Status Survey XR0200 SU2: Yard East Soil Area Investigation Scan Locations S011 ,S012,S019,S026,S028 ITR
~~ 4076 N ~ s _</t 407,4.8°L 1}
624,24p.1 E_ _//1111l l igation Grid
Attachment 2 Survey Unit Instrumentation FR-0200-02, Revision 0 Page 14 of 22
TABLE 2-1 INSTRUMENT INFORMATION E-600 SIN SPA-3 Probe SIN 1648 725890 1933 726557 2618 2366 IIPGe Detectors (Laboratory Analysis)
Detector No. MDC (pCi/g) 1 FSSI 0.04 to 0.10 l FSS2 0.03 to 0.07 l TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, AND INVESTIGATION LEVEL Parameter Instrument: SPA-3 Comments Scan MDC 5.9 pCi/g Cs-137 LTP Rev 3 Table 5-6 (Reference 2)
Approved DCGL for land areas DCGL 4.2 pCi/g Cs-137 outside the Restricted Area, LTP Section 6.7 (References 2 and 4) 9,700 cpm Group 1: Grids S002, S028, S031 Group 2: Grids S001, S003 through 11,300c.pm S012,S024,S026,S029,S030 Investigation Level Group 3: Grids S013 through S017, (Alarm Setpoint) 12,800cpm SO19,S023 13,800cpm Group 4: Grids S018, S020, S021, 13,800cpm GdS027
____________12,200 cpm Group 5: Grids SO22, S025 FR-0200-02, Revision 0 Page 15 of 22
Attachment 3 Investigation Table FR-0200-02, Revision 0 Page 16 of 22
TABLE 3-1 XR0200-02 INVESTIGATION SOIL SAMPLING RESULTS Elevated Grid EeaeGrd Initial ValueScan Alarm pointSet Invest.
Scaler Activity Uncertainty DCGL Sample Location (cPm) (cpM) Value (pCilg Cs-137) (pCilg Cs-137) Comparison Sampe Loatin (cm) (pm) (cPM)
XR0200023S01 1 11,870 11,300 9,400 < 5.33E-02 N/A < DCGL XR0200023S012 11,810 11,300 9,580 < 4.36E-02 N/A < DCGL XR0200023S019 12,970 12,800 11,090 < 5.76E-02 N/A < DCGL XR0200023S026 11,910 11,300 9,840 < 4.75E-02 N/A < DCGL XR0200023S028 9,880 9,700 9,470 < 4.94E-02 N/A < DCGL Survey Unit Mean / DCGL 0.014 Total 0.014 NOTES: 1. "<" indicates value less than MDA, MDA value is reported.
FR-0200-02, Revision 0 Page 17 of 22
Attachment 4 Statistical Data
(
FR-0200-02, Revision 0 Page 18 of 22
Survey Package FRO200 Unit 2 CS-137 Soil Sign Test Summary IEvauua t aori - we; o 'nts: ;m,-.
Survey Package: FRO200 Survey Unit: 02 Evaluator: Jeff Ambrose DCGLw: 4.20E+00 Cs-137 DCGL,: n/a Class 3 LBGR: 2.10E+00 50% of DCGL Sigma: 1.70E-01 LTP Rev 3, Table 5-1C Type I error: 0.05 Type II error: 0.05 Nuclide: CS-137 Soil Type: N/A No material background is applied.
Zr ,,: 1.645 Zo: 1.645 Sign p: 0.99865 Calculated Relative Shift: 12.3 Relative Shift Used: 3.0 Uses 3.0 if Relative Shift is >3 N-Value: 11 N-Value+20%: 14 Number of Samples: 14 Median: 5.26E-02 Mean: 5.76E-02 Net Sample Standard Deviation: 1.62E-02 Total Standard Deviation: 1.62E-02 Sum of samples and reference Maximum: 9.28E-02 Adjusted N Value: 14 S+ Value:j, 14 Critical Value: ; 10 Sign test results:, - ' Pass
',_ 'ctciW/t ___ ___ 'i;___ S . f'C &m en jt Sufficient samples collected: Pass Maximum value <DCGL,: Pass Median value <DCGL,: Pass Mean value <DCGL,: Pass Maximum value <DCGL,,: Pass Total Standard Deviation <=Sigma: Pass Criteria comparison results: Pass Z^<. . j-.inaifi sw , _ _ __ _ __ _ __ _ __
The survey unit passes all conditions: Pass __________________
FR-0200-02, Revision 0 Page 19 of 22
FRO200 SU-2 Quantile Plot 1 .OOE-01 -I 9.OOE-02 8.OOE-02 7.OOE-02 0
4- 6.OOE-02
< 0 N._
- Activity (pCi/g) sW W 5.OOE-02
" co w <
A:
0._
%%M 4.OOE-02
.. L L-Median (pCi/g) 0 3.OOE-02 2.OOE-02 I .OOE-02 O.OOE+OO -I 0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 3/22/05 11:49:09 AM Database Variable C2 Plots Section Histogram of FR-0200, SU-2 C,
E U) 2 z
Activity (pClg)
FR-0200-02, Revision 0 Page 21 of 22
One-Sample T-Test Power Analysis Page/Date/Time 2 3/31/05 7:55:51 AM Chart Section Retrospective Power Curve 1.0 I - ----- *-- - -
0.8 I
0.6 . I, - ,
0~
0 0.4 0.2 0.0 0
Survey Unit Mean (pCi/g)
FR-0200-02, Revision 0 Page 22 of 22