IR 05000312/2006004
| ML063400133 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/06/2006 |
| From: | Spitzberg D NRC/RGN-IV/DNMS/FCDB |
| To: | Shetler J Sacramento Municipal Utility District (SMUD) |
| References | |
| IR-06-004 | |
| Download: ML063400133 (34) | |
Text
December 6, 2006
SUBJECT:
NRC INSPECTION REPORT 050-00312/06-004
Dear Mr. Shetler:
March 20, 1997
SUBJECT:
CONFIRMATORY SURVEY RESULTS FOR THE REACTOR BUILDING DOME UPPER S T R U C T U W SURFACES, RANCHO SECO NUCLEAR GENERATING STATION, HERALD, CALIFORNIA (DOCIWT NO. 50-312, RFTA NO.06-003)
Dear A h. I-Iiclaiian:
The Oak lhdge Instihite for Science and Education (ORISE) performed conhinatoiy suivey activities on die Reactor Buildmg Doine Upper Struchiral Surfaces at die Ralicho Seco Nuclear Generating Station in Herald, California on June 7 and S, 2006. Tliese suivey activities were requested and approved by die U.S. Nuclear Regulatoiy Coiniiissioii (NRC). Enclosed are die coiif~inatoi-~~
suivey results documentbig these suivey activities. The survey activities included beta surface scans, &ect measurements for total net beta activity, and liiiited gross alpha and gtoss beta removable activity measurements.
If you have any questions or comments, please direct diem to me at 565.576.0065 or J. Scott 1G-k at S65.574.0685.
Sincerely, Wade C. Adams I-Iealtli Pliysicist/Project Leader Survey Projects WCA:ar Eiiclosure C:
B. Watson, NRC/NI\\/ISS/TWFN T-7ElS E. Abelquist, ORISE E. IGiox-Daviii, NRC/NMSS/TVDN SA23 E. Garcia/NRC/Region IV File/1695 S. I k k, ORISE Voice: S65.576.0065 Fax: 565241.3497 E-inad: AdarnsW@orau.gov
CONFIRMATORY SURVEY RESULTS FOR THE REACTOR BUILDING DOME UPPER STRUCTURAL SURFACES RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA INTRODUCTION The Sacramento Muiicipal Utdty District (SMUD) operated tlie Rancho Seco Nuclear Generating Station (RSNGS) froin 1976 to 1989 under Atoiiic Energy Coimiission Docket Number 50-312 aiid License Number DPR-54. In August 1989, SMUD notified the U.S. Nuclear Regulatoiy Coimnission (NRC) tliat tliey sliut down RSNGS permanently. In May 1991, SMUD submitted tlie Rancho Seco Decoimiissioiling Plan wlzicli was approved by tlie NRC in March 1995. SMUD began decoimnissioihg activities in Febivaiy 1997 and completed transfer of all the spent nuclear fuel in August 2002.
RSNGS was a 913-niIWe pressurized water reactor (PUR) designed by Beclitel Power Coiporation.
The plant incoiForated a pressurized mater type nuclear steam supply system (NSSS) supplied by Babcock and Wilcox Company; a turbine generator and electrical systems; engineered safety features; radioactive waste systems; fuel handhig systems; histrunentation and control systems; tlie necessay audalries; and stmctues to house plant systems and otlier onsite facilities.
Due to a public vote die previous day, on June 7, 1989, RSNGS permanently shut down after approximately 14 years of operation. On August 29, 1989, SMUD forlnally notified die NRC of die permanent cessation of operations at tlie RSNGS. SMUD subinitted the Post Shutdown Decoimiissioiing Activities Report (PSDAR), in accordance witli 10 CFR 50.82 (a) (4), 111 AiIarcli 1997. In A p d 2006, SMUD subinitted a license terinkiation plan (LTP) tliat has yet to be approved by tlie NRC (SMUD 2006a). SMUD currently is conducting decoiitainination efforts and performing final status smveys (FSS) in tlie remaining structural surfaces and open land areas.
The NRC requested tliat tlie Oak Ridge Institute for Science and Education (ORISE) perform a confu-matoiy survey of die upper sttuctwal surfaces of die Reactor Budding Dome at tlie RSNGS (Figures 1 aiid 2). Wde on site, tlie NRC site representative also requested tliat ORISE perform interlaboratoiy coinpallison analyses on several arclived soil samples tliat would be provided by RSNGS personnel. The conhnatoiy smveys were performed on June 7 and 8,2006.
PROCEDURES Confirinatoiy surveys were performed in accordance witli a site-specific surTey plan tliat was submitted to and approved by tlie NRC (ORISE 2006a). The site-specific survey plan follows tlie guidance provided in the ORISE Survey Procedures and Quality Assurance Manuals (ORISE 2004 and 2005).
Reactor Dome Umer Structural Surfaces Due to die dfficulty and hazards associated witli performing hand-held detector surveys of tlie Reactor Bdding Dome, SMUD opted to use tlie Contahinetit Bwldtng Surface Single Nuclide Renovation/Deinolition Scenario derived concentration guideline levels (DCGLs) for surfaces above tlie polar crane rail as described in Table 6-12 of die LTP (SMUD 2006a). In lieu of dmct Rancho Seco Nuclear Generating Station 1695\\Reports\\2006-10-25 Confxmatory Survey Results
surface activity ineasureiiient with hand-held ra&ological instrumentation, SMUD chose to perforin in. sits/ gaimiia spectcoscopy ineasurements of the doine surfaces (SMUD 2006b). The detector geoinetry for the dome survey was defined as a 28 square meters (in) circular plane wid1 a source to detector distance of 3 ineters (in). Each individual circular plane, also designated as die field-of-view (FOV), was designated at a p d or ineasmeinent location.
SMUD used site-specific suppleinental DCGLs for CO-60 and Cs-137 for deterinking surface release c~teria (SMUD 2006a and b). ORISE judgmentally selected five grid blocks for conhinatoiy surveys based upon final status survey (FSS) results which approached unity.
Beta surface scans were performed using hand-held gas proportional detectors coupled to rateineter-scalers with audlble indicators. Surface scans were performed on up to 80% of die judgmentally selected grid block surfaces. Particular attention was gveii to cracks, joints, aiid horizontal swfaces in die evaluated structural surfaces wliere material inay have accumulated.
Direct ineasureinents for beta activity were performed at 31 (a ininhim of five locations witlGii each grid) locations on tlie evaluated structural surfaces w l d i were avdable for conhiiiatory survey activities. Smear sainples were collected at tluee du-ect ineasureiiient locations of elevated suxface activity witlin Grid CRC052 to deterinine removable activity levels at these locations. Direct measurements locations are indicated on Figuxes 3 tluougli 7.
Interlaboratoiv ComDarisoii Soil Samples At tlie request of tlie NRC site representative, ORISE was tasked with conducting an interlaboratoiy coinparison to evaluate die quality of tlie licensees radioanalpcal procedures. Therefore, ORISE reviewed RSNGS characterization soil sainple data and selected seven soil samples, collected aiid analyzed by SMUD, for interlaboratoiy coinparison analyses. These samples were slGpped by SMUD personnel and received by ORISE laboratoiy personnel on July 10, 2006.
!?YAMPLE hALVSIS AND DATA INTERPRETATION Radlological data and sample iiiedia were returned to tlie ORISE laboratoiy in Oak Ridge, TN for analysis and inteiyretation. Raloassays were performed in accordance witli tlie ORISE Laboratoiy Procedures Manual (ORISE 2006b). Soil samples were analyzed by gaimna spectroscopy for tlie pximaiy radionuclides-of-coiicerii [POC @e., CO-60 and Cs-137)]. However, spectra were also reviewed for additional gaimna-emitting fission and activation products associated with tlie RSNGS and otlier identifiable total absorption peaks. Soil sainple results were reported in units of picoculries per grain (pCi/g). Diy smear samples were analyzed for gross alpha and gross beta activity using a low-baclrgound gas proportional counter. Smear results and direct measureinents for total surface activity were converted to uiits of lsintegratioiis per ininute per 100 square centimeters (dpin/ 100 cin).
FINDINGS AND RESULTS Reactor Dome Surface Activitv Measurements Beta surface scans identified several areas of elevated beta activity on tlie horizontally positioned inetal bracket. The brackets previously connected air conditioning ductworlr to die iiiside surface of tlie reactor buildlng walls. Beta surface scans dld not identify elevated beta activity on tlie vertical 1695\\Rcports\\2006-10-25 Confirmatory Survey Results
Rancho Scco Nuclear Generating Station
concrete surfaces of tlie Reactor Building Dome walls. Total net beta activity measurements ranged fkom -13,000 to 410,000 dpiii/lOO cin'. Removable activity nieasureiiieiits ranged fkoin 9 to 26 dpm/lOO ciii' for alpha and 230 to 890 dpin/lOO an' for beta. Surface activity level results are presented in Table 1.
Radionuclides DCGL Iiiterlaboratorv Sample kialvses Co-60" Cs-137" Gross Betab EMC" 40,200 182,000 43,000 593,400 Prior to shipping, SMUD re-analyzed die seven soil sainples selected by ORTSE. The analytical results for die coiiiparative evaluation of die RSNGS characterization samples are provided in Table 2. The results indicate tliat tlie quality of tlie SMUD laboratoiy data, w i t h die parameters of sample preparation and analytical procedures, were comparable witli ORISE's analytical results.
COMPARISON OF CONFIRMATORY SURVEY RESULTS AGAINST THE RELEASE CRITERIA The major contaiihmts identified by SMUD at RSNGS are beta-gaiima emitters-fission and activation products-resulting froin reactor operation. Cesimn-137 and CO-60 have been identified during characterization as die predoininant radionuclides present on structural surfaces. SMUD developed site-specific DCGLs (wluch have yet to be approved by tlie NRC) based on dose inodehg not to exceed 25 mem/year total effective dose equivalent (TEDE) as presented in Section 6 of tlie LTP (SMUD 2006a). The DCGLs for swfaces were modified by SMUD to reflect tlie ratio of radionuclide concentrations in tlie specific suivey units (Su> diat were being evaluated.
The applicable surface activity guidehies froin the LTP and decomSssioiing teclmical basis document (DTBD)-05-015 for die stmctwal surfaces above die polar crane in tlie Reactor Budding Dome are as follows (SMUD 2006a and c):
-
I Derived Concentration Guideline Levels (dpm/100 cm')
All of tlie duect beta activity measurement results on die concrete structural surface walls (vertical surfaces) were well witlin tlie DCGLs for CO-60 and Cs-137 as provided in tlie LTP (SMUD 2006a). The 25 duect measurement results (on tlie vertical concrete walls) were also witli.11 die gross beta activity DCGL as determined by SMUD personnel using die LTP and teclmical basis documents (SMUD 2006a, b and c). However, die six direct beta activity measurement locations on the metal brackets tliat exceeded die gross beta activity DCGL were typically less tlian 500 cin'.
SMUD determined two area factors tliat were not independently verified by ORISE, one for Cs-137 wlich was 14.9 and one for CO-60 which was 13.8; ORISE used tlie lowest area factor in deterinining tlie elevated measurement comparison (EMC) criteria for a 1 m2 area to be conseivative. Tlis corresponds to a DCGL,, of 593,400 dpm/lOO an2. All of die direct beta
Rancho Seco Nuclear Generating Station 1695\\Reports\\2006-10-25 Confirmatory Suiwy Results
surface activity ineasureinents on tlie metal brackets were less tliaii tlie SMUD derived DCGL,,,
for CO-60.
SUMMARY Beta surface scans identified several areas of elevated beta activity on the hollizontal surfaces of die reinair-Litlg metal brackets &tl&i tlie Reactor Budding Dome. Direct ineasureiiients were performed at 31 locations of wlich six locations were on tlie metal brackets; tlie rein&ting locations were on die vertical concrete walls. The 25 du-ect ineasureiiient results on tlie concrete walls (vertical surfaces) were well &tl&i die individual DCGLs for CO-60 and Cs-137 and tlie gross beta activity DCGL for st.mct7Lu.al surfaces. As tlie survey results indicated, hollizontal surfaces, such as on die iiietal brackets, exhibited elevated beta activity levels tliat exceeded die gross beta activity DCGL; however, tliese measurement locations were typically less than 500 ciii2 and were witllii die DCGL,,,,
release criteria. Therefore, die results of tlie survey activities for tlie upper stmctural surfaces of the Reactor Btulduig Dome confirmed tliat die radiologcal coiiditioiis meet tlie site-specific release criteria as presented in the licensees LTI.
ORISE performed interlaboratoiy comparison analyses on seven RSNGS cliaractellzation soil samples; tlie results inlcated tliat die quality of tlie SMUD laboratoiy data were coiisisteiit and in agreement witli ORISEs analytical results.
Rancho Seco Nuclear Generatins Station
lG95\\Reports\\2006-10-25 Confumatorp Survey Results
1695-001 (1)
>
N NOT TO SCALE FIGURE 1: Location of Rancho Seco Nuclear Generating Station, Herald, California Rancho Seco Nuciezu Gcneiahg Stahon
1695\\Repoits\\2006-10-~5 Coiiiumatoiy Suvey Results
16Y.5-902 (I)
TURBINE BUILDING ISFSI
/
I SPRAY PONDS SWITCHYARD I
/
ADMINISTRATION AUXILIARY BUILDING BUILDING NOT TO SCALE FIGURE 2: Plot Plan of the Industrial Area at Rancho Seco Nuclear Generating Station Rancho Seco Nuclear Generating Station
1695\\Reports\\2006-10-25 Confiinatoiy Survey Results
1695-003 (3)
///
-.,----
WlEASUREMENT LO CATIONS
- SINGLE-POINT
7
7 Ledge NOT TO SCALE FIGURE 3: Reactor Dome CRCO52 - Measurement Locations Raiicho Seco Nuclear Generating Station
1695\\Reports\\200G-l0-25 Confxrnatoiy Sun-ey Kesdts
1G95-004 (2)
17
MEASUREMENT LOCATIONS if SINGLE-POINT NOT TO SCALE FIGURE 4: Reactor Dome CRCO76 - Measurement Locations Rancho Seco Nuclear Generating Station S
1695\\Reports\\2006-10-25 Coi&matory Survey ltesults
1695-005 (2)
MEASURE&.NT LOCATIONS iY SINGLE-POINT NOT TO SCALE FIGURE 5: Reactor Dome CRC089-Measurement Locations Rancho Scco Nuclear Generating Station
1695\\Reports\\200G-10-25 ConfumatoT Survey Results
1695006 (2)
\\\\\\__
/------
--.----
MEASUREMENT LOCATIONS
$# SINGLE-POINT
2s
\\
NOT T O SCALE FIGURE 6: Reactor Dome CRCll4 - Measurement Locations Rancho Seco Nuclear Generating Station
1695\\Rcports\\2006-10-25 Confimatoiy Survey Results
1695-007 (3)
Ventilation Bracket Ledge 30,000 cpm
\\
Metal Bracket 21,000 cpm
11
E c
MEASUREMENT LOCATIONS
- SINGLE-POINT I
Metal Box 52,000 cpm
13 NOT TO SCALE FIGURE 7: Reactor Dome CRC168 - Measurement Locations liancho Seco Nuclear Generating Station
161)5\\Reports\\2006-10-~5 Confirmatory S u w y Results
TABLE 1 Locatioii/Grid Block" SURFACE ACTIVITY LEVELS REACTOR DOME UPPER STRUCTURAL SURFACES RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA Total Beta Activityb (dpin/IOO cm2)
Removable Activity (dpm/100 an')
Alpha Beta
2
4
6
S 79,000
230 150,000
330 41 0,000
590-6,800
__
__
-5,900
_-
__
-13,000
__
__
-2,soo
__
__
-370
__
__
10
12 (1 Grid CRC076 7,500
__
__
360 S90
__
__
__
__
2,700
__
__
~
ir
~~
27,000
__
_-
12.000
15
__
_-
13,000
__
__
12,000
1s
_-
__
-590
__
_-
12,000
~~
~
Rancho Seco Nucleac Gctieiatuig Station 1695\\Repoits\\200G-10-25 Confiiinatoiy Survey Results
12
__
__
4.500
21
23
__
_-
2,700
__
__
12,000-1,800-520
__
__
__
__
TABLE 1 (continued)
Locatioii/Grid B lo cl" SURFACE ACTIVITY LEVELS REACTOR DOME UPPER STRUCTURAL SURFACES RANCHO SEGO NUCLEAR GENERATING STATION HERALD, CALIFORNIA.
Total Beta Activityb (dpm/100 ciii')
Removable Activity (dpin/100 cm')
Alpha Beta
__
4,000
9,900
6,400
2,500
2,500
__
__
__
__
_-
__
__
__
__
Rancho Seco Nuclear Generating Station
30
13
__
__
75,000 210,000 280,000
__
__
__
__
1695\\Reports\\2006-10-25 Confirmatory Survey Results
TABLE 2 SMUD RADIONUCLIDE CONCENTRATIONS INTERLABORATORY COMPARISON SOIL SAMPLES RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA Previous Current Mil-5 4-0.15 t-0.15b
__
__
C Identification I Cs-134 Cs-137 ELI-1 52 Eu-154 Mil-54 CO-60 XBS100030DSOlA Radioiiuclide 0.05 k
0.07
__
__
46.6 I
1.6 61.2 86.4 0.03 k
0.20
__
__
0.06 i:
0.16
_-
__
1.2 k
2.5
__
__
2.86 I
0.16 2.9 3.19 Radiomiclide Concentratioii (pCi/g)
i Cs-134 Cs-137 SA81 OOOOODSOlA O N S E 0.13 I
0.08
-_
_-
113.1 k
3.7 115 122 SMUD" i
Eu-152 ELI-1 54 0.15 k
0.24
__
-_
0.08 k
0.16
_-
_-
CO-60 I
1.45 k
0.14 I 1.69 I
2.52 Mil-54 CO-60-0.02 I
0.05
__
__
2.75 I
0.12 5.63 2.83 Cs-134 Cs-137 SA83 7 00 1 D S 0 1 0.01 k
0.02
__
__
24.30 k
0.76 20.2 20.4 ELI-1 52 Eu-154 Mn-54 0.04 i:
0.09
__
__
0.04 IfI 0.08
__
__
0.13 k
0.16
_-
__
CO-60 Cs-134 Cs-137 Eu-152 Eu-154 Mn-54 SB 837001 DS 12 0.06 k
0.07 0.05 0.06 0.12 I
0.09
__
__
48.1 I
1.6 31.1 33.5-0.15 I
0.18
__
__
-0.03 I
0.12
__
__
0.00 k
0.01
__
__
CO-60 Cs-134 Cs-137 Eu-152 Eu-154 cc8430020s001ss Rancho Seco Nuclear Generating Station 0.37 k
0.05 0.34 0.34 0.01 I
0.02
__
__
4.46 I
0.18 4.25 4.11 0.02 I
0.06
__
__
-0.03 k
0.09
_-
__
1695 \\Reports\\7006-10-25 Confirmatoiy Sunrey Results
TABLE 2 (contiuued)
-0.11 k
0.19 0.04 k
0.03 RADIONUCLIDE CONCENTRATIONS INTERLABORATORY COMPARISON SOIL SAMPLES
]RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA
__
_-
0.09 0.06 Sample Identification Radioiiuclide 1.95 rt 0.10 0.00 k
0.06 ORISE 2.01 2.03
_-
__
1695S0006 0.02 k
0.09 0.05 k
0.07 1695S0007
__
__
_-
_-
§MUD I
Mil-54 CO-60 Cs-137 ccs430020s005ss I
Eu-152 Eu-154 Mn-54 I
Co-60 Cs-134 Cs-137 SlOOOlOSFPCP Radionuclide Concentration hCi/p.)
ORISE 0.04 t
0.03 I
--
I
--
0.12 2.09 0.09 1.42 0.01 k
0.03
__
__
I I-0.03 rt 0.05 I
_-
__
ace-60 and Cs-137 concentrations provided by SMUD personnel. Previous concentrations were performed during characterization surveys. Current concentration are when the site re-analyzes the samples prior to submitting them to ORISE.
LLJncertainties represent the 95% confidence level based on total propagated uncertainties.
CRadionuclide concentrations were not provided.
Rancho Seco Nuclear Generating Station
1695\\Rcports\\2006-10-25 Confirmatory Survey Results
REFERENCES Oak l d g e Institute for Science and Education (ORISE).
Survey Procedures Manual for the Eiivii-omnental Sumey and Site Assessment Program. Oak l d g e, Tennessee; September 2, 2004.
Oak l d g e Institute for Science aiid Education. Quality Assurance Manual for tlie Eiiviroimiental Sumey and Site Assessment Program. Oak Ridge, Tennessee; July 28,2005.
Oak Ridge Institute for Science and Education. Proposed Conhrinatoly Sumey Plan for die Reinainiiig Structural Surfaces, Embedded Piping, Standing Water aiid Open Lalid Area Survey Units, Raiicho Seco Nuclear Generating Station, Herald Cahforiia pocliet No. 50-312; WTA No.
06-0031. Oak Ridge, Tennessee; Juiie 2,2006a.
Oak l d g e Iiistitute for Science and Education. Laboratoiy Procedures Manual for Independent Eiivii-oiunental Assessment and Veltlficatioii Prograin. Oak Ridge, Tennessee; A p d 18, 2006b.
Sacrainento Municipal Utility District (SMUD). License Teunkation Plan, Raiicho Seco Nuclear Generating Station, Herald, California; April 2006a.
Sacranento Municipal Utility District. Decoilllnissioiling Tecluical Basis Document: Use of In Situ Gaimiia Spectroscopy for Final Site Survey. DTBD-06-003, Revision 0. Raiicho Seco Nuclear Geiierating Station, Herald, California; May 24,2006b.
Sacramento Municipal Utdity District. Decoimiissionhig Technical Basis Document: Sttucture Nuclide Fraction aiid DCGLs. DTBD-05-015, Revision 0. Raiicho Seco Nuclear Generating Station, Herald, Califoriia; June 2,2006~.
Rancho Seco Nuclear Generating Station 1695\\Reports\\2006-10-25 Confirmatory Survey Results
Sacramento Municipal Utility District 12/
/06 bcc w/enclosure (via ADAMS distribution):
LDWert CLCain J BHickmnan, N RR/DLPM/P D IV-2 ACMcMurray, NRR/DSSA/SPLB DBSpitzberg EMGarcia S PAtwa ter KEGardin FCDB File 1 2 6 /06
- 4 -
SUNS1 Review Complete: EMG ADAMS:
UNO Initials: EMG Publicly Available UNon-Publicly Available Elsensitive Non-Sensitive DOCUMENT NAME: s:\\dnrns\\!fcdb\\!ema\\rsO604.wod final r.\\ R9,\\7M16\\