ML081610167
| ML081610167 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/02/2008 |
| From: | Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-032 F8130321 | |
| Download: ML081610167 (20) | |
Text
Rancho Seco Final Status Survey Summary Report April 2, 2008.
Misc. Waste Concentrate Tank Room, (Room 024)
Survey Unit F8130321 Prepared By:
- i<
Date:il//*L.
F ES S iE*
Reviewed By:-
Date:
Lead F$S Engineer Approved By:
Date:_______
Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8130321, Misc. Waste Concentrate Tank Room, (Room 024)
Survey Unit
Description:
Operating 'History: The Misc. Waste Concentrate Tank Room is located on the -20' elevation of the Auxiliary Building. The Auxiliary Building is a reinforced concrete structure that, during power operations, contained the Radwaste processing and supporting systems. The building has six main elevations. Residual levels of surface radioactivity were detected on all interior elevations of the building. Operating records and the HSA document several events with the potential for a release of radioactivity inside this structure.
Site Characterization: Direct measurements were taken on each interior elevation of the Auxiliary Building. These measurements confirmed the presence of plant-derived radionuclides. Direct measurements taken on the -20' elevation, showed a mean gross activity level of 247,831 dpm/100 cm2 and a maximum value of 10,080,000 dpm/100 cm 2.
Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the interior surfaces of the Auxiliary Building were determined primarily to be a Class 1 for the floors and lower walls (bottom 2 meters of the walls), and Class 2 for the upper walls and ceiling. Inside the Misc. Waste Concentrate Tank Room there were a number of areas on the floor, lower and upper walls, and ceiling where the gross surface activity levels were higher than the DCGL prior to remediation. Therefore, a Class 1 final status survey was performed on the floor, wall, and ceiling surfaces of the room.
HSA Events: HSA Report pg. 63.
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 locations were determined using a random-start, fixed grid pattern and 153 m2 were scanned for 100% coverage. Samples of removable contamination were collected at each direct measurement location. The instrumentation used for the survey along with the MDC values are listed in' Tables 2-1 and 2-2 in Attachment 2.
Page 2 of 8 FSS Summary Report F8130321
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:
F813 0321 Survey Unit:
- Class:
SU Area (m2):
Evaluator:
DCGL (dpm/100 cm 2):
Area Factor:
Design DCGLemc (dpm/100 cm2):
LBGR (dpm/100 cm 2):
Design Sigma (dpm/100 cm2):
Type I Error:
Type II Error:
Predominant Nuclide:
Sample Area (m2):
Scan Area (m'):
Scan Coverage (%):
Sign P:
Calculated Relative Shift:
Relative Shift Used:
N-Value:
Design N-Value + 20%:
Design Min Samples N:
Grid Spacing L:
1I 153 Michael Stein 43000 3.5 150500 21500 12035 0.05 0.05 Cs-137 7
153 100%
1.645 1.645 0.955435 1.7 1.7 14 17 22 2.6 Misc. Waste Concentrate Tank Room, (Room 024)
Structure Surface LTP Table 5-4 Gross Activity DCGL Class 1 Class I Default = 50% DCGL Class 1 Class 1 Uses 3.0 if Relative Shift is
>3 NUREG-1575 Table 5-5 Class 1 Class 1 Page 3 of 8 FSS Summary Report F8130321
Survey Results:
A total of 29 direct measurements were made in F8 130321. The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. None of the scan measurements indicated areas of elevated activity. Scan activity ranged from 3,551 to 126,491 dpm/100 cm 2, based on a surveyor efficiency of 0.5 and no background subtracted. Samples for removable surface activity were all less than 10% of the DCGL as shown in Table 3. Removable surface activity samples were counted for alpha activity and none was detected at the MDC shown in Table 2-1 of Attachment 2.,
Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/100 cmr F8130321-CO001BD F8130321-CO002BD F8130321-CO003BD F8130321-CO004BD F8130321-C0005BD F8130321-CO006BD F8130321-CO007BD F8130321-CO008BD F8130321-Co009BD F8130321-Co01oBD F8130321-Co011BD F8130321-CO012BD F8130321-CO013BD F8130321-CO014BD F8130321-CO01 5BD F8130321 -CO016BD F8130321-CO017BD F8130321-CO018BD F8130321-CO019BD F8130321 -C0020BD F8130321-C0021BD F8130321 -CO022BD F8130321-CO023BD F8130321-CO024BD F8130321-CO025BD F8130321-CO026BD F8130321-CO027BD F8130321-CO028BD F8130321 -CO029BD Mean:
Median:
Standard Deviation:
Rancie:
2282 2428
-7812 1790 6671 6323 1,950
- 1463, 1608 1873 2205 1546 1634 2018 2070 1349 1385 1758 1660 1738 1629 1722
.1629 1582 21075 2101 1556 2044 3092 2379 1790 1628 1349-7812 Ranqe:
1349 - 7812 Page 4 of 8 a FSS Summary Report F8130321
Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2) 4-F8130321CO001SM F8130321CO002SM F8130321CO003SM F8130321 C0004SM F8130321C0005SM F8130321 C0006SM F8130321 C0007SM F8130321 COOO8SM F8130321CO009SM F8130321Co010SM F8130321CO01ISM F8130321 Co012SM F8130321CO013SM F8130321 COO 14SM F8130321C0015SM F8130321C0016SM F8130321 C0017SM F8130321CO018SM F8130321CO019SM F8130321 C0020SM F8130321CO02ISM F8130321 C0022SM F8130321 C0023SM F8130321CO024SM F8130321 C0025SM F8130321 C0026SM F8130321 C0027SM F8130321C0028SM F8130321 C0029SM Mean:
Median:
Standard Deviation:
Ranqe:
7.42 12.55 7.42 20.24 20.24 52.29 13.83 6.14 6.14 20.24 18.96 18.96 2.29 11.27 6.14 12.55 12.55 18.96 40.75 7.42 16.39 9.98 53.57 76.64 15.11 12.55 67.67 11.27 81.77 22.8 13.83 22.03 2.29 to 81.77 Page 5 of 8 FSS Summary Report F8130321 I
Survey Unit Data Assessment:
The survey design required 22 direct measurements for the Sign Test. In actuality 29 direct measurements were obtained. The critical value and the results of the Sign Test are presented in Table 4. 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 F8130321
Table 4. Data Assessment Results Survey-Results Parameter Value Comment Material Background Used (dpm/lO0 cmý2):
N/A Ambient Background Used (dpm/100 cm 2):
N/A Average Ambient BKG = 0 Actual Direct Measurements (N):
29 Median (dpm/100 cm 2):
1790 Mean (dpm/100 cm 2):
2379 Direct Measurement Standard Deviation 1628 (dpm/100 cm 2):
Total Standard Deviation (dpm/100 cm 2):
1628 Based on samples and backgrounds.
Maximum (dpm/100 cm 2):
7812 Material Type:
N/A Background Subtract Not Applied Sign Test Final N Value:
29 S+ Value:
29 Critical Value:
19 Sufficient Samples Collected:
Yes Maximum Value < DCGL:
Yes Median Value < DCGL:
Yes Mean Value < DCGL:
Yes Maximum Value < DCGLemc:
Yes Class 1 Total Standard Deviation <= Sigma:
Yes Pass the Sign Test?
Yes Reject the Null Hypothesis?
Yes Does the Survey Unit Pass All Criteria?
Yes Page 7 of 8 FSS Summary Report F8130321
Survey Unit Investigations and Results:
No investigations were required for either direct or scan measurements and 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 structure 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 and the scan coverage met the requirement of Table 5-6 of the LTP. No direct measurements exceeded the DCGL of 43000 dpm/100 cm 2 and none of the removable surface activity measurements exceeded 10% of 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 F8130321 meets the release criteria of 10CFR20.1402.
Page 8 of 8 FSS Summary Report F8130321
'Maps April 2, 2008 Survey Unit F8130321
- a...o
-I a-__
_8_'6 oZ I
EL..18,
.0m Lam E
24 X1E LLEEOT LLKNRTH FLOOR*
ROOM 24 BETADLECCTCLGOSE SURFAC 8
-~
8'2.6 4-1 AL
-87 ELEY ~
~
~
~
~
~
EE LKG EATELVLO OT EE KGWS RACTIVITY MEASUREMENT LOCATIONS o.CL
- O,,,
."¢r*
F81 30321 -M2 EL.i -0
~Imc ELER REý9 elAN~
MEITERS:
RC R*AONDI
('Q CD w
C,,
00 uj3 AU1 RY
/
7 7.
1/
~ 7
/
KEY PLANS i
SCALE 0
E METERS AUXILARY BULDING EL. -.20' ROOM 24 FLOOR. & CEILING PLANS BETA SCAN MEASUREMENT LOCATIONS F8130321-M1
- f:, 81.3000..2 SlIT 1 OF 2 RC RAYMO)4
~0
+.'o EtL 0*-Ov P6 P5 P3 P~2 PI EL -2o0--C ELEV LKG SOUTH Ps P7 9
SRAMENTO MUNICIPAL UTIUTY DISTRICT AUXILARY BULDING EL. -20' ROOM 24 WALL ELEVATIONS BETA SCAN MEASUREMENT LOCATIONS F81.30321-Mi 0 -
1
- 3 SCALE
- ETERS
(tI 0
uJ ELEV LKG SQUTH ShLRAENTO MUNICIPAL UTIIJTY DiSTRICT AUXILARY BULDING EL. -20' ROOM 24 WALL ELEVATIONS JUNCTURE BETA SCANS FS1 30321 -M4
....1 2...
SCALE METERS Instrumentation April 2, 2008 Survey Unit F8130321
Table 2-1. Survey Unit Instrumentation Instrument Detector.
MDC Static MDC Scan Model; Serial No.
Model; Serial No.
(dpm/100 cm 2)
(dpm/100 cm 2)
M2350; 180733 43-98B; 148638 1400 2520 M2350; 180733 43-94; 148620 590 1030 M2350; 193700 43-68B; 190294 433 1033 M2350; 142515 43-68B; 148453 433 1033 M2350; 149794 43-68/5B; 149103 433 1033 M2350; 193700 43-116-IB; 216072 796 3258 M2350; 142515 43-116-IB; 190173 796 3258 Tennelec; 0401171 N/A 5.2 dpm a, N/A 8.1 dpm f3 Table 2-2. Investigation Criteria and DCGL Value Parameter Value cm2)
(dpm/100 c2 Investigation Criteria - Direct 150500 Investigation Criteria - Scan 150500 DCGLw 43000 DCGLEMC 150500 Page 2 of 2 Att. 2 Instrumentation F8130321 Investigation April 2, 2008 Survey Unit F8130321 (none required)
)
Data Assessment April 2, 2008 Survey Unit F8130321
CF8130321 Gross Activity Sample Results Quantile Plot 0
DCGL = 43000 dpm/1 00cm2 9,000 7,
8,000 7,000 6,000 5,000 3~,000 2,000 2J~
1790 1,000 0
20 40 60 80 100
-Il Percentile
-~~
Direct Measurements (dprn/lO0cm2)
-median 75th Percentile --
- -50th Percentile K);;,
0" C:"D En3 cd3 cdp FB130321 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmll00cm=
10000
- 1 RE E
'0, 4000 8000 4000 0
' =m m
vm
=
m
=*
N
- i.
=rm **~0 0ti I
a, am J
t l=
l m
7264 2379 2000 1--* --- --- --
ý
-o-0 0
0 0
0 00 0000 0
0 0
-2000
,4000 I
I I
I I
I I
I I
I I
I I
I I
I I
I I
I I
I I
I I
i U_
1 1
1 1
" I 3
I I
a 0
0 0
0 0.V0TV-
- V V 0000080000000000t oUUUU UUUUoUUUUUo Doo 00 0a UU 03000000000 a000000000 a 0U C3aa 0 0 0 0 0
UU UUU UUUU ri1 00 C>
w Measurement Locations o
Gross Activity -
Average -
"+3StDev
"-3StDev"
(D 0
F8130321 Gross Activity Frequency Plot DCGL = 43000 dpm/1 00cm2 00 U-a*.
0 M'
16 15 14 13 12 11 109 8
7 6
5 4
3 2
10 4
O 41 4
9N 4
N-N4 Bins - Upper End.Va lue (dpm/1 00cm2)