ML082620100
| ML082620100 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/29/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-064 | |
| Download: ML082620100 (22) | |
Text
Rancho Seco Final Status Survey Summary Report May 29, 2008 Aux. Bldg. - Spent Fuel Bldg Transition +40' Survey Unit F8131812 Prepared By: Dan A. Tallman Reviewed Approved
'-'--'Date: May 29, 2008 Date:
Date:__-_7___
Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8131812, Aux. Bldg. - Spent Fuel Bldg Transition +40' Survey Unit
Description:
Operating History: The Auxiliary Building is a reinforced concrete structure which contained the RadWaste processing and supporting systems. The building contained six main elevations. Residual radioactive material was known to be present on all levels of the interior 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 made of each of the interior elevation surfaces as well, as the exterior surfaces of the structure. These measurements confirmed the presence of plant-derived radionuclides. Direct measurements on the +40' elevation showed a mean gross activity level of 3,288 dpm/100 cm 2 and a maximum value of 24,781 dpm/100 cm2. Direct measurements on the building exterior, including the mezzanine roof, showed a mean gross activity level of 1,897 dpm/l 00 cm 2 and a maximum value of 2,990 dpm/100 cm 2. Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the + 40' transition between the auxiliary building and spent fuel building was determined to be a Class 3 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 locations were randomly determined and 29 m2 were scanned for approximately 10%
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 F8131812
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:
F813 1812 3
Survey Unit:
Class:
SU Area (m2):
Evaluator:
DCGL (dpm/100 cm2):
Area Factor:
Design DCGLemc (dpm/100 cm 2):
LBGR (dpm/100 cm 2):
Design Sigma (dpm/100 cm 2):
Type I Error:
Type II Error:
Predominant Nuclide:
Sample Area (m2):
Scan Area (M2):
Scan Coverage (%):
Sign P:
Calculated Relative Shift:
Relative Shift Used:
N-Value:
Design N-Value + 20%:
Design Min Samples N:
Grid Spacing L:
283 D.A.Tallman 43000 N/A N/A 21500 3627 0.05 0.05 Cs-137 N/A 29 10%
1.645 1.645 0.99865 5.9 3
11 14 14 N/A Aux. Bldg. - Spent Fuel Bldg Transition +40' Structure Surface LTP Table 5-4 Gross Activity DCGL Class 3 Class 3 Default = 50% DCGL Class 3 Class 3 Uses 3.0 if Relative Shift is
>3 NUREG-1575 Table 5-5 Class 3 Class 3 Page 3 of 8 FSS Summary Report F8131812
Survey Results:
A total of 14 direct measurements were made in F8131812. 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 4057 to 6661 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 cm)
F8131812-CO001 BD 1681 F8131812-CO002BD 1909 F8131812-CO003BD 1681 F8131812-CO004BD 2002 F8131812-COOO5BD 1758 F8131812-CO006BD 1821 F8131812-CO007BD 1852 F8131812-CO008BD 1665 F8131812-CO009BD 1888 F8131812-CO01OBD 1888 F8131812-COOI1 BD 1743 F8131812-CO012BD 1276 F8131812-CO013BD 1577 F8131812-CO014BD 2090 Mean:
1774 Median:
1790 Standard Deviation:
200 Range:
1276-2090 Page 4 of 8 FSS Summary Report F8131812
Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2)
F8131812COOOISM F8131812CO002SM F8131812CO003SM F8131812CO004SM F8131812C0005SM F81 31812CO006SM F8131812C0007SM F8131812CO008SM F8131812CO009SM F8131812CO010SM F8131812C0011SM F8131812CO012SM F8131812C0013SM F8131812C0014SM Mean:
Median:
Standard Deviation:
Ranqe:
1.64
-3.53
-0.95
-2.24
-3.53
-4.82
-0.95 2.93 0.34 0.34 0.34 8.09
-3.53 2.93
-0.21
-0.3 3.42
-4.82 to 8.09 Page 5 of 8 FSS Summary Report F8131812
Survey Unit Data Assessment:
The survey design required 14 direct measurements for the Sign Test. 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 F8131812
Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2):
N/A Ambient Background Used (dpm/100 cm 2):
N/A Average Ambient BKG = 0 Actual Direct Measurements (N):
14 Median (dpm/100 cm2):
1790 Mean (dpm/100 cm2):
1774 Direct Measurement Standard Deviation 200 (dpm/100 cm2):
Total Standard Deviation (dpm/100 cm2):
200 Based on samples and backgrounds.
Maximum (dpm/1O0 cm):
2090 Material Type:
N/A Background Subtract Not Applied Sign Test Final N Value:
14 S+ Value:
14 Critical Value:
10 Sufficient Samples Collected:
Yes Maximum Value < DCGL:
Yes Median Value < DCGL:
Yes Mean Value < DCGL:
Yes Maximum Value < DCGLemc:
N/A Class 3 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 F8131812
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), the ALARA criterion has been met.
Changes in Initial Survey Unit Assumptions:
The survey unit was designed as a Class 3 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.
==
Conclusion:==
The FSS of this survey unit was properly designed as a Class 3 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 cm2 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 F8131812 meets the release criteria of 1 OCFR20.1402.
Page 8 of 8 FSS Summary Report F8131812 Maps May 29, 2008 Survey Unit F8131812
(D PLANT VENT AREA PLAN VIEW ELEV. 40O-0" PLANT VENT AREA REFLECTED CEILING VIEW ELEV. 59'-6"+/-
53 So M CONCRETE 6 SQ M STEEL RAILING It 00 w'
SACRAMENTO MUNICIPAL UTIWY DISTRiCT 0
1 2
3 4
5 SCALE METERS AUXILIARY BUILDING EL. 40-O'"
AREA AT PLANT VENT FLOOR & CEILING PLANS GENERAL ARRANGEMENT
-SURFACE AREA ESTIMATE F81 3182-M1 LE: 813000.05a SHEET 1 of 1 RC RAYMON
0 r*
E....
-~~
T
-1...
E T~~ Ia3 r
L*l
.11.1
- .S,,
L!
T:*,
A
,I,.,," -,-,.
-D VINF TN TEI X
T io -H -H !,--I H H H
,-!II li 1 1o i -
1
-11.1
..... ;.,+".- 14...
+
4 HT +F I- - i! !--
T T
T TE T
'u'I 00 0-IJ
"\\
I-i
-HHH-HH H +
H-I-4I-I11-H1111+
1+1 H-I-1
- 14.
-4HI---
I I'-H il---
I +...
I-....I-I-H f
1-H SACRAMENTO MUNICIPAL UTILITY DISTRICT AUXILIARY BUILDING EL. 40'-0" AB -
SFB TRANSITION FOYER BETA. DIRECT/REMOVABLE ACTIVITY RANDOM MEASUREMENT LOCATIONS F813182-M2
£"I" IC z
/
if
/
/LO
- r-('.PF E*IH 41-31
-~ vir~
PI~I t
1-2r=+/-
t I
I__________
FILE: 813000.05a SHEET 1 of 3 C
R{AYMOND 0
2 3
4 5
45 7
a 9
10 11 12 13 14 15 1
.5 17 Is 19 2a
I; i
Al (D
0g I
- I5-5'-7"l
-7
=
.2dN
-J
,.oz.
8*
OA 5/I OPEN
- ['---.2'-7 Oý<N V-1 4i-l2
.e-e 2EL
//
\\
PLANT VENT AREA DEVELOPED ELEVATION LOKKN N EAST ORTHm sarTFC LOINO NORTH. RES7 EL. 60'-0'
'-N I
B-SB RNIIO OE 00 K
I-0-/
EL.
I w
AUXILI-R B
EL.
40I-0" MTSAB SFB TRANSITION FOYER SM D
- BETA DIRECT/REMOVABLE ACTIVITY SARME'T I.IP MEASUREMENT LOCATIONS SCALE UT]LDrY DISTRICT F8 131 82-M2 MEER L~
1 000.05a SHEET 2 of _
RC
0 (xS JI-1 UEZ9 KEY PLANS PLANT VENT AREA PLAN VIEW ELEV. 40'-0" 00 00 PLANT VENT AREA REFLECTED CEILING VIEW ELEV. 59'-6*+/-
0 1
2 2
SCA~LE METERS
/
- SMUm SACRAMENTO MUNICIPAL UTILITY DISTRICT AUXILIARY BUILDING EL. 40'-0" AB -
SFB TRANSITION FOYER BETA DIRECT/REMOVABLE ACTIVITY MEASUREMENT LOCATIONS F81 3182-M2
EL. 60'-0"
.4>'
I":s '
I
'N
,v 22 1
e 8
w OPEN V "X EL. 40'-0' LOO__________________T_
OT SOUTHI LOOKM WEST PLANT VENT AREA DEVELOPED ELEVATION E L.
6M- 0
'O O K WN E A S T L O O GiN G
SO U TH.
L 0 0 10 NO N O R T H W E ST
-
- m. ;
A.
EL.
60'o,,
- 0" (0"t, 'N 0-
\\
n26
/" -
ft
/'
Itt!/
/
////7//
//1
//
PLANT VENT AREA ROOM 322 VESTIBLE DEVELOPED ELEVATION 00 LOOKING NORTH AUXILIARY BUILDING EL. 40'-0" AB -
SFB TRANSITION FOYER w
Muof BETA SCAN
- 0G ACTIVITY MEASUREMENT LOCATIONS 0
1 2
3 SACRAMEN'TO MUNICIPAL SCALE UTILIT RICT F81,31 81i -M3 METERS
ýW.
,FFT 1
,f Pr' PAV.A
A:
aQ 0
I KEY PLANS PLANT VENT AREA PLAN VIEW ELEV. 40'-0"
,-1 00 u'j PLANT VENT AREA REFLECTED CEILING VIEW ELEV. 5,9'-b+/-:
AUXILIARY BUILDING EL. 40'-0" AB -
SFB TRANSITION FOYER BETA SCAN ACTIVITY MEASUREMENT LOCATIONS F813181--M3 FILE: 813000.05a SHEET 2 of 2 RC 0
1 2
3 SCALE METERS Instrumentation May 29, 2008 Survey Unit F8131812
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No.
Model; Serial No.
(dpm/100 cm 2 )
(dpmll00 cm 2 )
M2350; 193715 43-68B; 160703 433 1033 Tennelec; 0401171 N/A 6 dpm a, 12 dpm r3 N/A Table 2-2. Investigation Criteria and DCGL Value Parameter Vmlue 2)
(dpm/100 cm)
Investigation Criteria - Direct 21500 Investigation Criteria - Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8131812 Investigation May 29, 2008 Survey Unit F8131812 (none required)
Data Assessment May 29, 2008 Survey Unit F8131812
(t--
0 CD) ct4 F8131812 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1 00cm2 2,500 2,000 ZI 1790 1,500 1,000 500 0
0 20 40 60 OA' COpV 100 I*-j 00 L0 00 K)
Percentile Direct Measurements (dpm/lOOcm2) -
median
-. _ 75th Percentile....
50th Percentile
CD 0
F8131812 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmrllOcm*
0 (00 cj*
cj*
00 2500 E 2000 15000 1000 0
0 0
.0 0
0 o
o 0
0 I
e*
4 i
4m I
m aol I I ~m ae I
e em i
- m I
i I
i I
emI0 2375 1774 1 1173 I
I I
5 I
S 00CA 00000 00 0
0 Me0U U
U U
U Measurement Locations I
o Gross Activity --
Average -
"+3StDev" -
"-3StDev "l
0 F81 31812 Gross Activity Frequency Plot DCGL = 43000 dpm/100cm 2 6
5 ci) ci)
L.
C0 CU 8
4-3 2-I 0
CD N-10I'-
CO Sij 00 00 t'J Bins - Upper End Value (dpm/1 00cm2)