ML051520394
| ML051520394 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 05/23/2005 |
| From: | Dockins L, Packer J, Pillsbury G, Randall D Maine Yankee Atomic Power Co |
| To: | NRC/FSME |
| References | |
| FR-0111-19, Rev 0 | |
| Download: ML051520394 (24) | |
Text
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-0111 YARD WEST EXCAVATIONS SURVEY UNIT 19 Prepared By: % ,I 4a Date: /9-FSS Engineer - Signature 4 le --f a h"-
Printed Name Reviewed By: C- ° Date: 5 - OS Fs ~pecialist -Signature
_Printed Name Reviewed By: o k_
Independent Review - Signature Date: i/52-0*
Approved By: Date: 5/>D ende nature Printed Name Approved By: A Date: 4.s::~_
r~SS, MOP - Signature
- Trics -chy N.e Printed Name Revision 0
MAINE YANKEE FINAL STATUS SURVEY RELEASE RECORD FR-O111 YARD WEST EXCAVATIONS SURVEY UNIT 19 A. SURVEY UNIT DESCRIPTION FR-01 Il Yard West Excavations Survey Unit 19 was located north of the former Containment Building. The 1,080 m2 area was bordered on the West by FA-0400 Survey Unit 1, (Fuel Building Footprint). The survey unit was centered near coordinates 407,640N and 624,OOOE using Maine State Coordinate System (West Zone) NAD 1927. The location of the survey unit in relation to the Containment Building and the surrounding FR-0l 11 survey units is shown on map FROl1 1U19-SITE (Attachment 1).
Survey Unit 19 consisted mainly of soil material. There were areas of exposed concrete remnants from miscellaneous structures. The surface was highly irregular with deep excavations as shown on map FROl 1 UI9-INFO.
B. SURVEY UNIT DESIGN INFORMATION Survey Unit 19 met the LTP Revision 4 definition for a Class 1 survey unit. The survey unit design parameters are shown in Table 1. Given a relative shift of 0.8, it was determined that 40 direct measurements were required for the Sign Test. The measurement locations were based on a systematic square grid with a random start point as illustrated on map FROI I 1U19-DIRT (Attachment 1). Direct measurements (soil samples) were collected from required locations and analyzed with laboratory gamma spectroscopy instrumentation.
In accordance with the LTP, scans covering 100I of the 1,080 m2 area were required for the Class 1 survey unit. This was accomplished by use of an in situ gamma spectroscopy detector (ISOCS) configured at a 3-meter distance (2-meter distance for concrete surfaces with a 12 m.2 field of view) from the surface to obtain overlapping 28-m2 fields of view. The ISOCS detector was positioned perpendicular to the surface, as appropriate, to provide 100%
scan coverage. Locations and orientation (vertical or horizontal) of the 140 survey scans are shown on maps FROI I U19-SCAN, FROI1 IU19-NONVERT, FROI I IU19-CONC, and FROlIIUI9-HOLE.
The ISOCS scans were configured to ensure 100% scan coverage of all exposed surfaces within Survey Unit 19. The survey instruments used 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 DCGLEmc. The scan MDC is less than the scan investigation level, thus providing high confidence (95% or higher) that an elevated area would be detected in the scanning process. Further, since the investigation level was always less than the design DCGLEMC, no EMC sample size adjustment was necessary.
FR-0111-19,Revision0 Page 2 of 23
TABLE 1 SURVEY UNIT DESIGN PARAMETERS Survey Unit Design Criteria Basis Area 1,080 nin Class 1, < 2,000 m2 Based on an LBGR of 1.2 pCifg, Number of Direct 40 sigma' of 1.33 pCi/g, and a relative Measurements Required shift of 0.8.
Type l = TypeII = 0.05 Sample Area 27.0 rn2 1,080 m2/ 40 = 27.0 in2 Sample Grid Spacing 5.2 m (27.0)__
Scan Grid Area ISOCS scan at 2 and 3 See Section B
__ _ __ _ _ __ _ _ _ _ _ _ _ _ _ m eters _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Area Factor 1.8 Class 1 Area, LTP Table 6-12 Scan Area 1,080m Class I Area- 100%
1.0 pCi/g Cs-137 ISOCS investigation levels with Scan Investigation Level 0.36 pCi/g Co-60 detector at 2 and 3-meter height
____ ________ ___(Reference
___ 3)
DCGL 2.39 pCi/g Cs-137 Reference 1
_ __ __ _ __ _ _ _ _ _ _ _ 0.86 pC il Co-60 _ _ _ _ _ _ _ _ _ _ _ _
. 4.30 pCi/g Cs-137 DCGL x Area Factor for Class 1 Design DCGLEMC 1.55 pCi/g Co-60 survey unit, per LTP Section 5.6.3 C. SURVEY RESULTS A total of 40 direct samples were performed in Survey Unit 19. Four samples contained Cs-137 with levels of residual activity below the DCGL. All other measurements were below the MDA. The results are presented in Table 2.
ISOCS gamma scans were performed at 140 locations using investigation levels of 1.0 pCi/g Cs-1 37 and 0.36 pCi/g Co-60. Forty-nine of the locations scanned consisted primarily of concrete media, the balance were soil scan measurements. Media appropriate geometries were applied to each ISOCS measurement. The gamma scans were performed for a sufficient count time to achieve a Minimum Detectable Activity (MDA) of approximately 30% of the DCGL. All identified scan activity levels and MDAs were below the investigation levels. Therefore, no investigation surveys were performed as a result of the scan surveys.
A small number of scan measurements had water within some portion of the field of view.
The most affected measurement was evaluated by modeling with a 100% water layer as an attenuator. The evaluation determined that MDAs were sufficient to detect residual activity below the investigation levels.
LTP Revision 4, Table 5-IC for RCA Yard West, ROI00 FR-01 11-19, Revision 0 Page3of23
TABLE 2 DIRECT MEASUREMENTS Sample Number Cs-137 (pCi/g) Uncertainty (pCi/g)
FROII1191SODI 7.98E-O2 3.29E-02 FRO1119ISO02 < 4.82E-02 FROIII191SO03 < 4.48E-02 FR0111191S004 < 5.25E-02 FR0111191S005 < 3.56E-02 FRO11191SO06 < 4.78E-02 FRO111191SO07 < 5.53E-02 FR0111191S008 9.88E-02 2.92E-02 FRO111191SO09 < 6.74E-02 FRO11119ISO10 < 4.65E-02 FRO11I19ISOII < 5.32E-02 FROII1191SO12 < 5.60E-02 FROII191SO13 < 6.03E1-02 FROII I91SO14 < 6.20E-02 FRO1III9ISOlS < 4.80E-02 FRO11I191SO16 < 5.27E-02 FRO1II19ISO17 < 4.14E-02 FROII19lSO18 < 5.03E-02 FRO11119ISO19 < 3.94E-02 FR011119ISO20 < 4.62E-02 FROIII91SO21 < 5.83E-02 FR0111191S022 < 5.24E-02 FR0111191S023 < 5.27E-02 FROIII191SO24 < S.OSE-02 FR0111191S025 < 6.30E-02 FROii91SO26 3.28E-01 5.04E-02 FR0111191S027 < 5.70E-02 FRO 11191S028 < 7.1SE-02 FR011119IS029 < 4.61E-02 FRO11119lSO30 < 3.96E-02 FROIII19lSO31 < 4.76E-02 FR0111191S032 < 7.OOE-02 FR0111191S033 < 4.60E1-02 FR0111191S034 < 5.14E.02 FRO111191SO35 1.70E-01 3.68E-02 FR0111191S036 < 5.19E-02 FR0111191S037 < 4.59E1-02 FR0111191S038 < 4.28E-02 FR0111191S039 < 4.21E-02 FRO111191S040 < 4.74E-02 .-
Mean 6.30E-02 Median 5.17E-02 Standard Deviation 4.82E-02 Range 3.56E-02 to 3.28E-01
"<"indicates MDA value. Bold indicates positive detection value.
All Co-60 values were <MDA.
FR-O1 I 1-19, Revision 0 Page4of23
D. SURVEY UNIT INVESTIGATIONS PERFORMED AND RESULTS Based on the scan results, no investigations were required.
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. Positively detected values are bolded in the table. Of the 40 samples collected, 4 identified Cs-137 activity below the DCGL value of 2.39 pCi/g. All other Cs-137 values and all Co-60 values were below the MDA. Identified sample activities or Minimum Detectable Activities are listed in Table 2.
The mean and median activities were less than the DCGL for Cs-l37. The average of the residual Cs-137 DCGL level was 0.063 pCi/g, indicating that the direct measurements averaged 2.6% of the DCGL limit. Since Co-60 was not positively detected, it is assumed not to be present.
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-137 value (0.19 pCi/g) 2 for disturbed soil from the survey unit sample mean activity (0.063 pCi/g). This would equate to an annual dose rate of 0.0 mrenl/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 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 5A.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. The direct measurements clearly pass the Sign Test. The subject release criteria have been satisfied. In addition, 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 2).
FR-.0 11-19, Revision 0 Page 5 of23
- 2. The Quantile Plot was generated from the data listed in Table 2. The data set and plot are consistent with expectations for a Class 1 survey unit. All of the measurements are below the DCGLs of 2.39 pCi/g for Cs-137 and 0.86 pCilg for Co-60 for land inside the restricted area.
- 3. A Histogram Plot was also developed based on the Cs-l37 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 I land survey area; the FSS results were consistent with that 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 19 was designed, performed, and evaluated in May 2005. The design was performed to the criteria of the LTP Revision 4 (Reference 1). 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 1 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 2.39 pCi/g Cs-137.
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 log-normal distribution with two outliers.
FR-0I 11-19, Revision 0 Page 6 of 23
The scan survey design for this survey unit was developed in accordance with the LTP Revision 4 (Reference 1) with significant aspects of the design discussed in Section B and Table 1. ISOCS scans performed at a distance of 2 or 3 meters in a systematic grid pattern throughout the survey unit did not identify activity above the scan investigation levels of 1.0 pCi/g Cs-137 and 0.36 pCi/g Co-60. Therefore, no investigations were required as a result of the scan process.
It is concluded that FR-01 1I Survey Unit 19 meets the release criteria of 10CFR20.1402 and the State of Maine enhanced criteria.
J. REFERENCES
- 1. Maine Yankee License Termination Plan, Revision 4, February 28, 2005 provided by Maine Yankee letter to the NRC, MN-05-010
- 2. 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
- 3. Maine Yankee Calculation No. EC-003-04, Use of Canberra In Situ Object Counting System (ISOCS) for FSS Surveys FR- I11-19, Revision 0 Page 7 of 23
Attachment 1 Survey Unit Maps FR-O1 11-19, Revision 0 Page 8 of 23
DecMrnelani"reTe r I Maine Yankee DecommissioningProject Survey map MpID# FRO 1IU19.SITE SurveyType: Characterization Turnover
- FhnaSAtus SurvW SurveyArea Name: Site Location I.O.,g.oo VAt La7.500 "
L07.I tA 0
.077°1 t CY, 0Ci r"
Ca Ml a,
aC U.~
a 0 Co rn C, tl' of FR-0I11-19, Revision 0 Page 9 of23
IIr 0
0 W 6
i fog_
x e 0_ ;.
To I IgI_...
0 0 b 5dm 0_
m K
- 2. ;
D %
9 0
a a
0
- 3.6m I SOOl 5003
.l I 4.94m -I I -4 S004 S005 S006 S007 S008 S009 solo Soil S42 2 mS03 T014 5 7.5m 0 0.26m S016 S017 S018 S019 S020 S021 S022 S023 S024 S025 S026 S027 S028 t x I: II& )w ) I I U 0 (S042) (S043) t 25.2m 2.8ml PI se
< 5 2m--.
S029 S030 S031 S032 S033 S034 l3.Om :! Q11 x X ' x I ;3 5.2m 14.8m It S035 S037 S038 S038 S040 i .4-52rn 39 4.66nT I,
S036 L-T 4.66m 9'
_ . l l _ .
I
/71 3.Grn l2.4m a' 0.0I 32m z9 ref. 37m 0
'0 cc 0
o.
'p- 0 CM . n 0 a
.0
_ Io 0 CD w w (A w a, II . . . . I I . I . I -L- I 1-1w1mohni6" I I I I i I C o
I 5Om o
)C< Note: Points outside the orea ore necessary to ensure overaopping scan coverage. However, they may be moved in to the boundarys edge. 3Q, o 8 0
S001 S002 S003 S004 S005 S006 SO 008 S009 SO10 SOI0 S012 S013 S014 S015 S016O S01 0 E 2 S,1 S022 S023 X X X X X X X X X X X X SO 4 S025 S026 S027 S028 S029 S030 S031 S032 S033 S034 S035 S036 S037 S038 S039 S040 S041 S042 S043 S044 S04f S 6 S047 S048 S049 S050 S051 S052 S053 3 S054 S055 S056 S057 S058 S059 S06 0 I I PI m 3l
,50m o9 o-O CA
a IE 0
t3 a
0 C
2?
U 0 Q!.
9 X
'4-w
- v C
0)04' F
I I I I I i I 6111,11,11imillooll" I I , I i I I I I I I I . . I I . .
m l I I I I -
co I
In 50m 0l aD A
W0I0 0
'Od?
aCD CD CZ4 0
Iz 1
CD
- S I0-S, 0
0 th
r-9 CD aa:35 A 93 a
a a4 ft U
a
- 3 6 '1 0,
_ 0 0d
-4o fa ag tj -
0 W.
01 S C I I i I I I 1111111 Ii I Ii II 0 t) 6 50m 0
_0 XU 0
0 0
- 8
9Q.
3I:0a 0
a3 ar a
I L) l PtI a 0
-t
\I j d22 f..
0
+b 02 H015 H009 11 0 =_
oh 3O3 IIt 11021 tA ~ '1.
w Cx*
N a>
llr,~N U O 0
- S (D
4 1023 H024 X IN m V' 8 0T
!I ad 8 C '0 l l0 HCOS MOO?
X X 0 0 rr
- r aCA H014 H013 CD 2cp m
1X1 I X 0
t MI Holet I 0
O-4 kl 0
(
m
Attachment 2 Survey Unit Instrumentation FR-01 11-19, Revision 0 Page 16 of 23
TABLE 2-1 INSTRUMENT INFORMATION ISOCS Detectors (Field Measurements)
Detector Number MDC (pCi/g) 7607 0.09 to 0.46 7780 0.12 to 0.39 7722 0.15 to 0.37 7897 0.15 to 0.26 HPGe Detectors (Laboratory Analysis)
Detector Number MDC (pCi/g)
I FSS1 0.04 to 0.08 FSS2 0.04 to 0.07 DET2 0.07 to 0.09 TABLE 2-2 INSTRUMENT SCAN MDC, DCGL, INVESTIGATION LEVEL AND DCGLEMc Parameter Instrument: ISOCS Comments Scan MDC 0.14 to 0.46 pCi/g Cs-I 37 - 30% DCGL
_________________ 0.09 to 0.25 pCi/g Co-60_ _ _ _ _ _ _ _ _
2.39 pCi/g Cs-137 Approved DCGL for land DCGL 0.6pigC-0areas inside the Restricted Area, (References 1)
Investigation Level 1.0 pCi/g Cs-137 (
(ISOCS @ 2 and 3 m) 0.36 pCi/g Co-60 (Reference 3) 4esi0 pGi/g Cs5137/DCGL x Area Factor for Design DCGLEMC 4.0~C17Class 1 survey unit, per 1.55 pCilg Co-60 LT? Section 5.6.3 FR-01 11-19, Revision 0 Page 17 of 23
Attachment 3 Investigation Table (No Investigations Required)
FR-01 11-19, Revision 0 Page 18 of 23
Attachment 4 Statistical Data FR-0111-19, Revision 0 Page 19 of 23
Survey Package FROIII Unit 19 CS-137 Soil Sign Test Summary Survey Package: FRO111 Survey Unit: 19 Evaluator: DR DCGL, 2.39E+00 only Cs-1 37 detected DCGL,,,: 4.30E+00 LBGR: 1.20E+00 Sigma: 1.33E+00 Type I error: 0.05 Type II error: 0.05 Nuclide: CS-1 37 Soil Type: N/A 9 ?6' Je1 .64 5
_Zj.p: 1.645_
Sign p: 0.788145 Calculated Relative Shift: 0.8 Relative Shift Used: 0.8 Uses 3.0 If Relative Shift is >3 N-Value: 33 N-Value+20%: 40
-AN;Ai Number of Samples: 40 .-
Median: 5.177E-02 Mean: 6.30E-02 Net Sample Standard Deviation: 4.82E-02 .-
Total Standard Deviation: 4.82E-02 Sum of samples and reference Maximum: 3.28E-01 Adjusted N Value: 40 S+ Value: 40 Critical Value: 25 Sign test results: - Pass Sufficient samples collected: Pass Maximum value <DCGL,: Pass Median value <DCGLw: Pass Mean value <DCGLw: Pass Maximum value <DCGL,,: Pass Total Standard Deviation <=Sigma: Pass Criteria comparison results: Pass The survey unit passes all conditions: Pass SU Passes FROI 1I-SU19-SoifSign-CS-l137 5/1l8O5 3:31 PM FR-01 11-19, Revision 0 Page 20 of 23
FRO111 SU=19 Quantile Plot 3.50E-01 3.OOE-01 0~ 2.50E-01 a C5
= ft- 2.OOE-01
- Activity (pCi/g)
O I
- <C 1.50E-01 - Median (pCi/g)
O s.
w~ :5.
3.
4.
.A.
0 3:U 1.OOE-01 5.OOE-02 O.OOE+O0 0 25 50 75 100 Percent
One-Sample T-Test Report Page/Date/Time 2 5/19/05 11:10:33AM Database C:\Program Files\NCSS97AFRO1 11 SU-1 9.S0 Variable C2 Plots Section Histogram of FR-01 1. SU-19 c
C)
VI zj 0
E Activity (pCUg)
FR-OI 11-19, Revision O Page 22 of 23
One-Sample T-Test Power Analysis Page/Date/Time 2 5/16/05 12:10:45 PM Chart Section Retrospective Power Curve 1.0-s .-
0.84-L.
0.64-0~
0.4-0.2 n n1 \6 u.uV I 0.0 0.5 1.0 l
1.5 -2I 2.0 - 2.5 Survey Unit Mean (pCi/g)
FR-01 11-19, Revision 0 Page 23 of 23