ML082620158
| ML082620158 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 07/29/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-064 F8130171 | |
| Download: ML082620158 (28) | |
Text
Rancho Seco Final Status Survey Summary Report June 19, 2008 AB-20' corridor column T - east Survey Unit F8130171 Prepared By: Dan A. Tallman Date: June 19, 2008 FSS Engine r Reviewed By: - Date: Cy )z3 (V*
Lead FSS Engineer Approved By: Date: 7'O Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F8130171, AB -20' corridor column T - east Survey Unit
Description:
Operating History: The Auxiliary Building is a reinforced concrete structure that 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. The direct measurements on the -20' elevation showed a mean gross activity level of 247,831 dpm/100 cm 2 and a maximum value of 10,080,000 dpm/100 cm. Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the -20' corridor east of column T within the interior of the auxiliary building was determined to be a Class 1 area.
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 310 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 9 FSS Summary Report F8130171
Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F813 AB -20' corridor column T - east Survey Unit: 0171 Structure Surface Class: 1 LTP Table 5-4 SU Area (m2): 309.9 Evaluator: D.A.Tallman DCGL (dpm/100 cm'): 43000 Gross Activity DCGL Area Factor: 3.5 Class 1 Design DCGLemc 153866 Class 1 (dpm/100 cm 2):
LBGR (dpm/100 cm 2): 21500 Default = 50%/o DCGL Design Sigma (dpm/100 cm 2): 12035 Type I Error: 0.05 Type II Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m): 6.89 Class 1 Scan Area (M2 ): 310 Scan Coverage (%): 100% Class 1 Zl-, : 1.645 1.645 Sign P: 0.955435 Calculated Relative Shift: 1.7 Relative Shift Used: 1.7 Uses 3.0 if Relative Shift is >3 N-Value: 14 Design N-Value + 20%: 17 NUREG-1575 Table 5-5 Design Min Samples N: 45 Class 1 Grid Spacing L: 2.6 Class 1 Page 3 of 9 FSS Summary Report F8130171 ,
Survey Results:
A total of 45 direct measurements were made in F8130171. 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 2460 to 43561 dpm/l100 cm2 , based on a surveyor efficiency of 0.5 and no background subtracted. ISOCS scan activity on the walls and ceiling ranged from 982 to 2972 dpm/100cm 2 for Cs-137 with all scans less than MDA for Co-60. 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.
Page 4 of 9 FSS Summary Report F8130171
Table 2. Direct Measurement Results
.Y.
Measurement ID Gross Activity (dpm/100 cm
.4-F8130171-C0001BD 1712 F8130171 -CO002BD 2469 F8130171 -CO003BD 2070 F8130171-CO004BD 1696 F8130171-CO005BD 1816 F8130171-CO006BD 1722 F8130171-CO007BD 1665 F8130171-CO0OBBD 975 F8130171 -CO009BD 1032 F8130171 -CO01OBD 1395 F8130171-CO011BD 1784 F8130171-CO012BD 1515 F8130171-Co013BD 1639 F8130171-CO014BD 1437 F8130171-CO015BD 1318 F8130171-CO016BD 1629 F8130171 -CO01 7BD 1478 F8130171-CO018BD 1660 F8130171--Co019BD 1323 F8130171-CO02OBD 1499 F8130171-CO021BD 1489 F8130171-CO022BD 1525 F8130171-CO023BD 1432 F8130171-CO024BD 1359 F8130171-CO025BD 1198 F8130171 -CO026BD 1577 F8130171 -CO027BD 1639 F8130171 -CO028BD 1385 F8130171 -CO029BD 1484 F8130171 -CO03OBD 1655 F8130171-CO031BD 1432 F8130171-CO032BD 1.333 F8130171-CO033BD 1624 F8130171 -CO034BD 1624 FB130171 -CO035BD 1312 F8130171-CO036BD 1286 F8130171-CO037BD 1499 F8130171-CO038BD 1261 F8130171-CO039BD 1567 F8130171,C0040BD 1515 F8130171-CO041BD 1261 F8130171-CO042BD 1468 F8130171 -CO043BD 1458 F8130171 -C0044BD 1426 F8130171 -CO045BD 1478 Mean: 1514 Median: 1489 Standard Deviation: 247 Ranqe: 975 - 2469 Page 5 of 9 FSS Summary Report F8130171
Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2)
F8130171COOOISM 4.22 F8130171 C0002SM -3.53 F8130171 C0003SM 0.34 F8130171 C0004SM -3.53 F8130171C0005SM -0.95 F8130171 C0006SM -4.82 F8130171 C0007SM -3.53 F8130171 C0008SM 1.64 F8130171 C0009SM -2.24 F8130171CO010SM -3.53 F8130171CO011SM 5.51 F8130171 Co012SM 2.93 F8130171C0013SM 0.34 F8130171CO014SM 2.93 F8130171CO015SM 4.22 F8130171Co016SM -0.95 F8130171Co017SM 8.09 F8130171Co018SM 18.42 F8130171C0019SM 8.09 F8130171 C0020SM 0.34 F8130171 C0021 SM 9.38 F8130171 C0022SM 1.64 F8130171 C0023SM -3.53 F8130171C0024SM -3.53 F8130171 C0025SM -0.95 F8130171 C0026SM -0.95 F8130171 C0027SM 1.64 F8130171 C0028SM 6.8 F8130171 C0029SM 2.93 F8130171 C0030SM 5.51 F8130171CO031SM 13.26 F8130171 C0032SM 31.34 F8130171 C0033SM -3.53 F8130171 C0034SM -3.53 F8130171 C0035SM 23.59 F8130171 C0036SM 2.93 F8130171 C0037SM 5.51 F8130171 C0038SM -2.24 F8130171C0039SM 13.26 F8130171CO040SM 5.51 F8130171CO041SM 11.97 F8130171 C0042SM 5.51 F8130171 C0043SM -2.24 F8130171 C0044SM -3.53 F8130171 C0045SM 1.64 Mean: 3.57 Median: 1.64 Standard Deviation: 7.72 Range: -4.82 to 31.34 Page 6 of 9 FSS Summary Report F8130171
Survey Unit Data Assessment:.
The survey design required 45 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 7 of 9 FSS Summary Report F8130171
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): 45 Median (dpm!100 cm 2): 1489 Mean (dpm/100 cm 2): 1514 Direct Measurement Standard Deviation 247 (dpm/100 cm 2):
Total Standard Deviation (dpm/100 cm 2): 247 Based on samples and backgrounds.
Maximum (dpm/100 cm 2): 2469 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 45 S+ Value: 45 Critical Value: 28 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes
.Mean Value < DCGL: Yes Maximum Value < DCGLemc: Yes Class I Total Standard Deviation <= Sigma: Yes Pass the Sign Test? Yes Reject the Null Hypothesis? Yes Does the Survey Unit Pass All Criteria? Yes Page 8 of 9 FSS Summary Report F8130171
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. Therefore the EMC criterion was met.
==
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 F8130171 meets the release criteria of 10CFR20.1402.
Page 9 of 9 FSS Summary Report .F8130171
Attachment 1 Maps
'June 11, 2008 Survey Unit F8130071
Attachment I Maps June 19, 2008 Survey Unit F8130171
CD 0
ltl' Looking North Looklim West LooW*nNorth Shield Wai Looking East rl -,
I V) ,(., KEY PLAN 00 OW 0-
~Looio ot C
Looking South Ceing Looldng North Area Under Stais FIn__
00 General Surface Area Estimates Scale Feet tJ.
Ceilng - 63.6 m 2 it"= l,-0, AUXILIARY BUILDING EL. -20 Walls- 183.0 ml2 Scale Meters ROOM 15 EAST OF COLUMN "T" Floor- 63.3 m *smun SACRAMENTO MUNICIPAL SURFACE AREA ESTIMATE Total - 309.6 m 2
0 1 2 345 UTILITY DISTRICT F8130171-M1 FIIF 8130O0.O~ *FIT 1 t")F 1 T C HILL FIIF 13000e SA-T 1 OF 1
.............. ....T; i..... i....-; I" * / E ! -.. . . . .'ii . . . . . . . . . . .i .... ....
i1 --
fn Ili-."..........HH!
_ H-..... H..... HmH*H. H 1 !1 i----
m H-H-I-I-. T.,. h.
HI:HIlK 4
....................T . .. ..
I IW Hi-Hi-H- . ik
. . ..+H+H....T,_
- H H.
....... ;TH.........
.... I.-.. ,.i.....
H-I Th1
....i ....
Th.... .H
. . . . . . . ......... . 4 ...
- ='.
=-,................,.....--* *
- T-. ... . . . .. . . . ..
Hi-H..... H-.-.-.-I-H-I-I-H-l.-
..- I-I-I-Hi-
... I H-.-I-l LHinn T--~f-
- i. ....
+I-H-H-H T Ed iH 1T H-.H.....
7-..
fII ..
T...
t.
H m+I+I-H+: -H H-l-H--..i-II-IH-......TloI M..
- 1
-HH--
[
" +° ....
HI I H -H I .......
I
. . H--H-H+H-II I
.......-.........I . . . . ..
H
+
ii- .....
H -
- 3. .. . . .1H
. 4 .. . . 0 I1 .. .. . 3'41 .. . SII1 .. . . H J. iiiiiiiii fill!!!!! !H ..... 1_, 1,-I.T .H il',t H HIH !IH11H, HH...........................i- ... .. ..in...Thin4 H-Hi-HI H.IIH..i-11-H..inIHl.!....
TAUXILIARY BUILDING EL. -20 ROOM 15 T EAST oF COLUMN "T" B S...............LOOSE SURFACE RANDOM START 03 1 4[. * * ~~~UTILITY 0ISTRICT F8150171-FILE 813C0.02e SPIT OF 3 T C HILL a 1 2 3 4 1 a T a 9 'D 11 12 13 *4 15 0* 17 a '9 20
0o
-0 Fb)-
00 Scale Feet
-l" = 1,-0" L*J 0 32 AUXILIARY BUILDING EL. -20 ROOM 15 Scale Meters EAST OF COLUMN "T" BETA/DIRECT
- SACRAMENTO MUNICIPAL LOOSE SURFACE MEASUREMENT LOCATIONS 0 .1 2 3 UTILITY DISTRICT F8130171 -M2 FILE 81300.02e SHIT 2 OF 3 T C HILL
(J)
C-)
Looking North Looking West Area Under Stairs Looking South Scale Feet 00 23-0 AUXILIARY BUILDING EL. -20 ROOM 15 Scale Meters, EAST OF COLUMN "T" BETA/DIRECT osm*u SACRAMENTO MUNICIPAL LOOSE SURFACE MEASUREMENT -LOCATIONS 0 1 2 3 UTILITY DISTRICT F81 30171 -M2 FIL 81300, 02o S 30F T CHILL
01 0
Reflected Ceiling C,,
00 Scale Feet Field Of View - 12.56 ma 81"ý= 1,-0"'
W. AUXILIARY BUILDING EL. -20 ROOM 15 0
Scale Meters 1 2 3
- SACRAMENTO MUNICIPAL UTILITY DISTRICT EAST OF COLUMN "T" GAMMA SCAN MEASUREMENT LOCATIONS F81 30171 -M3 eFfILEl10 02e S 1 nF4 T C HILL
(T) 00 U)
I Looking North LookiIng West Looking South Scale Feet Field OtVAew - 12.56 nW 00 33= 1,-0" AUXILIARY BUILDING EL. -20 ROOM 15 Scale Meters WEST OF COLUMN "T" 0 1 2 3 osmu* SACRAMENTO MUNICIPAL GAMMA SCAN MEASUREMENT LOCATIONS UTILITY DISTRICT F8130171-M3 FILE 81300.02a SHT2 OF4 T C HILL FILE 81300.02o SHT2OF4 TCHILL
0 00 Gi G US SoQuth L, okIng Norti AreaUnder Stairs Shield Wall 1-. 22-33 void f). 09V3 I .~ I' Is l C.35 ) ý (:E)
(:i*ýi) . . .
GDG~G~G~ 1 -:'K
-.:' '.'T-
- .*..... ; j.I.* , A
(!t)
GD s GD D Gj G
E-ý)06 jj E.G)(D(i
-G-4_ I D H
_ _ ~.
Floor O0 Scale Feet 00 1.= 1 -0" AUXILIARY BUILDING EL. -20 ROOM 15 w-.
Scale Meters 1 2 3
- mm SACRAMENTO MUNICIPAL UTILITY. DISTRICT FiL 02aC R13009 EAST OF COLUMN "T" BETA SCAN MEASUREMENT LOCATIONS F81 30171 -M3 S 3F4 T C HILL
(T)
(D 10 a
GD GD LookIniNoth 00 Scale Feet 00 8"n= 1'-0r AUXILIARY BUILDING EL. -20 ROOM 15 EAST OF COLUMN "T" Scale Meters
- smu1 SACRAMENTO MUNICIPAL BETA SCAN MEASUREMENT LOCATIONS 0 1 2 3 UTILITY DISTRICT F8130171 -M3 FILE 81300.02e SH-T4 OF 4 T C HILL FIIE 81300.02e SHT4OF4
Note: with eXCePUitof ojuncturesdetailedbelow-juncture evatuation will be associated with GammeScansurveys ofwalls and'ceeing'surfaces. *!'
0 0000 D C, Looking South Celing Looking North Area Under Stairs Lohi nd Woal
- Lootrino East En, Ii Floor 00 Scale Feet W* I" = 1- AUXILIARY BUILDING EL. -20 ROOM 15 Scale Meters EAST OF COLUMN "T"
- Smum SACRAMENTO MUNICIPAL JUNCTURE BETA SCAN LOCATIONS 0 1 2 3 UTILITY DISTRICT F81 30171 -M4 FiLE 81300.02e SHT 1 OF 1 T C HILL FILE 81300.02o SHT1OF1 TCHILL
'-Ii" Y Y (ti 0
PeneiraUon Do-il P--at.iPttms managed Shield Wag from adiacent survey uni LooKhinNoul LookringEast On a)~i o a, a-
- ec Caflig I . C cc)
Looidno South 00 Scale Feet 1
Uj~ 6" = 1,-0" AUXILIARY BUILDING EL. -20 ROOM 15 Scale Meters EAST OF COLUMN "T" osmu*
SACRAMENTO MUNICIPAL PENETRATIONS 012345 UTILITY. DISTRICT F8130171 -M5 FF 5513fl002e 5*HT i rir 1 T C HILL FILE 813013 02e 1OF1
Attachment 2 Instrumentation June 19, 2008 Survey Unit F8130171
Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cm') (dpm/100 cm2 )
990A 550A M2350; 142514 43-98B; 148639 820B 1490B M2350; 175834 43-68B; 148634 433c 1033 C 796 c 3258 M2350; 175834 43-116-iB; 190642 472D 1930D 739E 49 1E Tennelec; 0401171 N/A 6 dpma, 12 dpmJ3 N/A A Penetration - 3" - metal B Penetration - 4" - metal c Surfacescan - concrete D Surface scan - metal E Juncture - concrete Instrument Detector MDC Model; Serial No. Model; Serial No. (dpm/100 cm 2 )
989 (Co60)
ISOCS 1983920 1340 (Cs137) 3920_2mconcrete geometry 12.5 M2 FOV Table 2-2. Investigation Criteria and DCGL Parameter Value (dpm/100 cm 2 )
Investigation Criteria - Direct 153866 Investigation Criteria - Scan 153866 DCGLw 43000 DCGLEMC 153866 Value (dpm/100 cm 2 )
Instrument Parameter To detect a 1 m hot spot at the EMC Criterion within the detector field of view Investigation Criteria - 63,300 dpm/100 cm2 Cs-137 ISOCS Concrete Scan 1', 2 21,275 dpm/100 cm 2 Co-60 3920 2mconcrete geometry 12.5 m2 FOV 2 2 Investigation Level set to 43,000 dpm/100cm Cs-137, ND Co-60 for investigation survey instructions.
Page 2 of 2 Att. 2 Instrumentation F8130171
Attachment 3 Investigation June 19, 2008 Survey Unit F8130171 (none required)
Attachment 4 Data Assessment June 19, 2008 Survey Unit F8130171
F81 30171 Gross Activity Sample Results Quantile Plot 2
DCGL = 43000 dpm/1OOcm 3,000 2,500 CD 2,000 Z%1,500 1489 1,000 500 0
0 20 40 60 80 100 ITIl Percentile 00 S Direct Measurements (dpm/100cm2) - median - - -75th Percentile -... 50th Percentile 0j
CD P8130171 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmli00cm=
3000' p2500 0 E
0 0 2255
> 32000-
" 15E -----
00000 ---
00 -- o0 0 00 - °°--o-g-6-0o
-e-*
0 0 00 1514 p~ 5. 15000-0 1 -- 0 p0aaoaPma 0 0 0 0 00 00 0a.10 0 a 0 54 00 InŽ1000 CDC 500 l-a 000 aaoooGrossAaaaao -Averageaoo00000000000000
0 F8130171 Gross Activity Frequency Plot DCGL = 43000 dprn/1 00cm 2 19 18 17 16 15 14 all 13 12 11 C 10 0 9 8
CD)
En~ 76 5
4 3
2 1
0 LC)
C)
OT1 (NJ 00 w.
Bins - Upper End Value (dpm/1 00rcm2)