ML090830321
| ML090830321 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/09/2009 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097, F8100012 | |
| Download: ML090830321 (20) | |
Text
Rancho Seco Final Status Survey Summary Report January 9, 2009 Tank Farm S.W. Quadrant - Subsurface Soil - including "A" Stm Sump and SF Cooler pad areas Survey Unit F8100012 Prepared By: Dan A. Tallman
. 1I
-Date:
January 9, 2009 FSS Engine/er Reviewed By: --'
L Date:
109(
0 Lead FSS Engineer Approved By:
Date:
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8100012, Tank Farm S.W. Quadrant - Subsurface Soil - including "A" Stm Sump and SF Cooler pad areas Survey Unit
Description:
Operating History: This area is located between the Reactor Containment, Auxiliary, and Spent Fuel buildings. During plant operation numerous support systems were routed through this area. Subsequent to plant operations, this area was used as a transport corridor for remedial waste. The HSA document several events with the potential for a release of radioactivity associated with this survey area. The HSA documented the storage of radioactive material within the area that may have had the potential to contaminate the area.
Site Characterization: As documented in F8100011, surface soil samples were collected and analyzed for the presence of plant-derived radionuclides. Cs-137 was the primary nuclide of plant origin detected with a mean activity level of 379 pCi/g and a maximum value of 1,040 pCi/g.
Based on the potential for sub-surface contamination within the unit, the decision to perform an investigation of the sub-surface soil was made. This investigation resulted in the collection of 40 soil samples, 'the locations of which coincided with those of the surface soil evaluation. The results of these samples and the statistical tests performed are also consistent with the evaluations performed on the surface soil component evaluated in F8100011. Based on the classification procedure (DSIP-0020) and consistent with the classification applied to the surface soil component, the area was designated a Class 1 land area.
Survey Unit Design Information:
The Survey Unit Design Parameters are presented in Table 1 below. The survey unit and measurement locations are depicted on the maps in Attachment 1. Direct measurement spatial locations were based on the surface soil locations sampled in F8 100011. Sub-Surface samples were then collected at one meter intervals. Samples taken from a depth of-15 cm (depth of surface soil samples) to -115 cm are designated as minus one meter (-
1m) samples while those taken from the interval -115cm to -215 cm are referred to as minus two meter (-2m) samples. Due to the existence of numerous sub-surface utility support structures (piping, cable duct-boxes, sewer lines, etc.) as well as over dimension fill and debris existing undetected below grade level, sample refusal was not an uncommon occurrence. No incidents of refusal culminated in an inability to acquire a two meter sample within a one meter radius (the relocation allowance criteria) of the surface and one meter sample locations. Each soil sample taken was analyzed by HPGe detector.
The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.
Table 1. Survey Unit Design Parameters Page 2 of 8 FSS Summary Report F8100012
Survey Design Parameter Value I
Comment Survey Area:
F810 Survey Unit:
Class:
SU Area (m2):
Evaluator:
DCGL Cs137 surrogate (pCi/g):
Area Factor:
Design DCGLemc (pCi/g):
LBGR (pCi/g).
Design Sigma (pCi/g):
Type I Error:
Type II Error:
Nuclide:
Sample Area (i2):
Total Area Scanned (m2):
Scan Coverage (%):
Sign P:
Calculated Relative Shift:
Relative Shift Used:
N-Value:
Design N-Value + 20%:
Grid Spacing L:
0012 1
672 D.A. Tallman 51.2 1.4 74.2 25.6 10.7 0.05 0.05 Cs137 44.8 0
0%
1.645 1.645 0.97725 2.3 2.3 12 15 6.7 Tank-Farm S.W. Quadrant -
Subsurface Soil - including "A" Stm Sump and SF Cooler pad areas Open Land Area LTP Table 5-4 IAW F8100011 IAW F8100011 CLASS I lAW F8100011 CLASS I Default = 50% DCGL lAW F8100011 DTBD-06-001, Table 5-4D
- IAW.F8100011 IAW F8100011 CLASS I NA - Subsurface Soil NA - Subsurface Soil Uses 3.0 if Rel Shift >3 NUREG-1575 Table 5-5 Class 1 Page 3 of 8 FSS Summary Report F8100012
Survey Results:
A total of 40 direct measurements were made in F8100012. The results including mean, median, standard deviation and range are shown in Table 2. All of the direct measurements were less than the DCGL. Soil samples were counted to the MDC shown in Table 2-1 of Attachment 2.
Page 4 of 8 FSS Summary Report F8100012
Table 2. Direct Measurement Results (all activity values in pCi/g)
Measurement ID Cs137 MDA Cs137 Activity Uncertainty Mean: ~K1.42E-0OI Median:
>5.48E-02 Standard Deviation;:~ ~~
7 i 2.3 1E-01 I Range:
2.55E-02 to 1.08E00 F8100012SO01ISS 1.1OE-01
< 1.1OE-01 F8100012SO02ISS 7.35 E-02 1.97E-01 6.22E-02 F8100012S0031SS 4.58E-02 7.78E-02 3.45E-02 F8100012SO041SS 4.47E-02 5.14E-02 3.10E-02 F8100012S0051SS 1.02E-01
< 1.02E-01 F8100012SO06ISS 5.38E-02 8.02E-01 8.75E-02 F8100012S0071 SS 5.93E-02 2.56E-01 5.73E-02 F8100012S0081SS 1.35E-01 1.08E00 1.62E-01 F8100012S0091SS 5.52E-02 7.87E-01 8.35E-02 F8100012SO10ISS 4.22E-02
< 4.22E-02 F8.100012S011ISS
- 6. 1OE-02 2.82E-01 6.47E-02 F8100012SO121SS 4.97E-02
< 4.97E-02 F8100012SO131SS 4.32E-02
< 4.32E-02 F8100012S0141SS 5.53E-02
< 5.53E-02 F8100012S0151SS 5.42E-02
< 5.42E-02 F8100012S0161SS 6.02E-02 1.50E-01 5.25E-02 F8100012SO17ISS 5.21E-02
< 5.21E-02 F8100012S0181SS 5.72E-02 1 16E-01 4.37E-02 F8100012S0191SS 5.82E-02
< 5.82E-02 F8100012S020ISS 6.92E-02
< 6.92E-02 F8100012S0012SS 6.08E-02
< 6.08E-02 F8100012S0022SS 3.60E-02 3.83E- 02 2.53E-02 F8100012S0032SS 5.58E-02
< 5.58E-02 F8100012S0042SS 4.02E-02
< 4.02E-02 F8100012S0052SS 4.88E-02
< 4.88E-02 F8100012S0062SS 3.32E-02
< 3.32E-02 F8100012S0072SS 4.70E-02
< 4.70E-02 F8100012S0082SS 3.70E-02 3.89E-0 1 5.66E-02 F8100012S0092SS 4.48E-02
< 4.48E-02 F8100012SO102SS 4.35E-02
< 4.35E-02 F8100012SO112SS 5.34E-02
< 5.34E-02 F8100012S0122SS 3.66E-02
< 3.66E-02 F8100012S0132SS 5.53E-02
< 5.53E-02 F8100012S0142SS 5.08E-02
< 5.08E-02 F8100012S0152SS 4.21E-02
< 4.21E-02 F8100012S0162SS 2.55E-02
< 2.55E-02 F8100012S0172SS 2.57E-02
< 2.57E-02 F8100012S0182SS 6.79E-02
< 6.79E-02 F8100012S0192SS 3.98E-02
< 3.98E-02 F8100012S0202SS 5.88E-02
< 5.88E-02 0
Page 5 of 8 FSS Summary Report F8100012
Survey Unit Data Assessment:
The survey design required 40 direct measurements for the Sign Test. The critical value and the results of the Sign Test are presented in Table 3. The sample mean and median values were less than the DCGL. The sample standard deviation was less than the design standard deviation so no additional samples were required.
Page 6 of 8 FSS Summary Report F8100012
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N):
40 Median (pCi/g):
5.48E-02 Mean (pCi/g):
1.42E-01 Standard Deviation (pci/g):
2.3 1E-01 Maximum (pci/g):
1.08E00 Sign Test Final N Value:
40 S+ Value:
40 Critical Value:
25 Sufficient Samples Collected:
Yes Maximum Value < DCGL:
Yes Median Value < DCGL:
Yes Mean Value < DCGL:
Yes Maximum Value < DCGLemc:
Yes Class 1 Standard Deviation <= Sigma:
Yes Pass the Sign Test?
Yes Reject the Null Hypothesis?
Yes The survey unit passes all conditions?
Yes Page 7 of 8 FSS Summary Report F8100012
Survey Unit Investigations and Results:
No investigations were required for direct measurements, therefore no investigation results are reported.
ALARA Statement:
As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit is less than the DCGL (i.e. the survey unit average activity is less than the DCGL and the EMC criterion has been met), the ALARA criterion has been met.
Changes in Initial Survey Unit Assumptions:
The survey unit was designed as a Class 1 land survey and the sample results are consistent with that classification. The variability of the survey results was less than the characterization data used for survey design. No potential areas of elevated activity were detected.
==
Conclusion:==
The FSS of this survey unit was properly designed as a Class 1 survey based on Table 5-4 of the LTP. The required number of direct measurements was made. As a subsurface soil survey, the scan coverage is not applicable. All of the direct measurements were less than the DCGL. No investigations were required.
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.
It is concluded that survey unit F8100012 meets the release criteria of 10CFR20.1402.
Page 8 of 8 FSS Summary Report F8100012 Maps January 9, 2009 Survey Unit F8100012
(0 0t Emergency Petsonnel hatch Structure (exduded)
Key Plan Electrisal Reactor Building 0
0N Spent Fuel Building Approximate Zone 1 surface area-672 m-1, includes structural concrete pad Scale: 3/64" = 1.0' Meter Scale 0
1 2
3 4
5 10 TANK FARM -
ZONE 1 GENERAL ARRANGEMENT PLAN VIEW SURFACE AREA ESTIMATE F810001 1-Mi 810001 SHEET 1 of 2 TC
('D 0
-t Detail 1 to be survey as Containment exterior D
LooKing South Emergency Personnel Hatch Root Looking West Looking East Key Plan Detail 2 LONUIJUo r IoasItli Looking Do-_ ¶-th l D Looking Down Looking East Looking South LookJng West Looking Noith Electrical Slab 00 L'J Scale: 1/16" = 1.0' Meter Scale
- SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT TANK FARM ZONE 1 STRUCTURE ELEVATION VIEW F8100011-M1 FILE: 810001 SHEET 2 of 2 0
1
-~
2 3
4 5
TC HILL
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if !iii I
+ +
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w MESRMNTOAIN XL 8100 TOHL
entire row 17:1 re~ocated one meter south Electrical Slab 19 Key Plan GDD 1210 17 GD "21 GD (I 2-10 F
04 0n 0j t8-4
'ý Plan View Tank Farm Zone 1 TANK FARM-ZONE 1 oo SOIL SAMPLE /
DIRECT GD W*
EmCALMEASUREMENT LOCATIONS SACRAMENTO MUNICIPALT F81 00011 -M2 FIE: 810001 SHEET 2 of 2 TC HILL Instrumentation January 9, 2009 Survey Unit F8100012
Table 2-1. Survey Unit Instrumentation Detector Detector Serial MDC Instrument Model No.MDC
.No.
Soil - 0.135 pCi/g Cs-137 Soil - 0.129 pCi/g Co-60 Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value HPGe Investigation Criteria 74.2 pCi/g Cs137 surr.
All DCGLw 51.2 pCi/g Cs-137 12.6 pCi/g Co-60 All DCGLEMC 74.2 pCi/g Cs 137 surr.1 LTP Chapter 5, Table 5-7, Investigation Levels for Class I Survey units = DCGLEMC - 74.2 pCi/g Cs137 Page 2 of 2 Att. 2 Instrumentation F8100012 Investigation January 9, 2009 Survey Unit F8100012 (none required)
Data Assessment January 9, 2009 Survey Unit F8100012
-e K\\)
0 ý (D
WEn E3, C)
F8100012 Quantile Plot Cs137 DCGL = 51.2 pCi/g 1.200 1.000 0.800 0.80
>, 0.600 0.400 0.200 0.000 0
20 40 60 Percentile 80 0.055 100 I
Activity -
Median -
- - 75th Percentile - -.-. 50th Percentile I
-e CD 0
F8100012 Scatter Plot Cs137 DCGL = 51.2 pClIg Cn Cn Ua.
1.20E+00 1.OOE+00 8.O0E-01 6.OOE-01 4.00E-01 2-00 E-0 I O.OOE+O0
-2.0OE-01
-4,00E-01
-6.OOE-01
-8.OOE-01 0
0 0 0 0o" 0
0 0 O 0
O0 0oc.0 oo oo00o00o0 0
0 o
, 0.835
, 0.142
, -0.551 88888888886SS SS 888888888SS8 6
Measurement Locations 1 0 Acdivity -
Average -
"+3S1Dev" -
"-3StDev'I I-]
00 k)
-e 0
(12 (J2 (t~
(i-i (L~
-Ii 00 L'J F8100012 Frequency Plot Cs1 37 DCGL = 51.2 pCi/g 38-36-34-32 32 30-
~29-24-2-
0-cv NN Bins - Upper End Value (p0 I/g)