ML090480582

Confirmatory Survey Results for Activities Performed in April and May 2008 for the Rancho Seco Nuclear Generating Station

ML090480582
Person / Time
Site:	Rancho Seco
Issue date:	08/29/2008
From:	Adams W Oak Ridge Institute for Science & Education
To:	John Hickman NRC/FSME
References
DCN 1695-SR-03-1, DE-AC05-06OR23100, RFTA 06-003
Download: ML090480582 (40)

Text

CDG]R-llI S 1H OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION August 29, 2008 Mr. John Hickman Mail Stop: T-8F5 Office of Federal and State Materials and Environmnental Management Programs U.S. Nuclear Regulatory Commission 11545 Rockville Pike Rockville, MD 20852-DOE CONTRACT NO. DE-ACO5-06OR23100

SUBJECT:

REVISED INTERIM LETTER REPORT -CONFIRMATORY SURVEY RESULTS FOR ACTIVITIES PERFORMED IN APRIL AND MAY 2008 RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA DCN 1695-SR-03-1 (DOCKET NO. 50-312, RFTA NO.06-003)

Dear Mvr. Hickman:

The Oak Ridge Institute for Science and Education (ORISE) performed confirmatory survey activities on the Auxiliary Building structural surfaces (Rooms 10, 15, 40, 42, 51 and 52), the Pump Alley, the Fuel Storage Building exterior excavation, and portions of the Rad Waste and Acid Waste drain systems at the Rancho Seco Nuclear Generating Station in Herald, California on April 14 through 17 and May 29, 2008. These survey activities were requested and approved by the U.S. Nuclear Regulatory Comnmission (NRC). Enclosed is a revised interim letter report to replace the report, issued on July 24, 2008, that contained figures that were misprinted.

This revised report summarizes ORISE's survey procedures and preliminary results of the confirmatory survey. The surveys included beta and gamma surface scans, direct measurements for total net beta activity, and smears for removable alpha and beta activity within the Auxiliary Building; embedded piping gamma scans within the Auxiliary Building; and limited gamma scans and the collection of soil samples in the Pump Alley and the Fuel Storage Building exterior excavation.

If you have any questions, please direct them to me at 865.576.0065 or Tinm Vitkus at 865.576.5073.

Wade C. Adams' s ORISE Health Physicist/Project Leader Survey Projects WCA:km Enclosure c: T. Carter, NRC/FSI\ME/DWMEP/DD/SP T-8F5 E. Abelquist, ORISE E. IKnox-Davin, NRC/FSMvIE/TWn'FN 8A23 S. Roberts, ORISE T. Youngblood, NRC/FSME/D\VIVIEP/TWFN 8 F5 T. Vitkus, ORISE E. Garcia, NRC/Region IV' File 1695 Distribution approval and concurrence:

Initials T'echnic.I Management Team Member `1V Labortor ManerI QualityManager (AX F. @6, 9M Voice: 865.576.0065 Fax: 865.241.3497 E-mail: Wade.Adams@orau.org REVISED INTERIM LETTER REPORT CONFIRMATORY SURVEY RESULTS FOR ACTIVITIES PERFORMED IN APRIL AND MAY 2008 RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA Prepared by W. C. Adams Prepared for the U.S. Nuclear Regulatory Commission AUGUST 2008 ORISE This report is based on worked performed by the Oak Ridge Institute for Science and Education under contract number DE-AC05-06OR23100 with the U.S. Department of Energy.Rancho Seco Nuclear Generating Station 1695-SR-03-1 REVISED INTERIM LETTER REPORT CONFIRMATORY SURVEY RESULTS FOR ACTIVITIES PERFORMED IN APRIL AND MAY 2008 RANCHO SECO NUCLEAR GENERATING STATION HERALD, CALIFORNIA INTRODUCTION The Sacramento Municipal Utility District (SMUD) operated the Rancho Seco Nuclear Generating Station (RSNGS) from 1976 to 1989 under Atomic Energy Commission Docket Number 50-312 and License Number DPR-54. In August 1989, SMUD notified the U.S. Nuclear Regulatory Commission (NRC) of the RSNGS's permanent shutdown.

In May 1991, SMUD submitted the Rancho Seco Decommissioning Plan (DP) which was approved by the NRC in March 1995. SMUD began decommissioning activities in February 1997 and completed transfer of all the spent nuclear fuel in August 2002 (SMUD 2006a).In April 2006, SMUD 'submitted a license termination plan (LTP) that the NRC approved on November 26, 2007 (SMUD 2006a and NRC 2007). SMUD is currently conducting decontamination efforts and performing final status surveys (FSS) on the remaining structural surfaces and in open land areas.The NRC requested that the Independent Environmental Assessment and Verification (IEAV)Program of the Oak Ridge Institute for Science and Education (ORISE) perform confirmatory surveys of structural surfaces in several Auxiliary Building rooms, the Pump Alley, the Acid Waste System and Rad Waste System drains in the Auxiliary Building and the Fuel Storage Building exterior excavation at the RSNGS (Figures 1 and 2). The confirmatory surveys were performed during the period of April 14 through 17 and May 29, 2008.PROCEDURES Confirmatory surveys were performed in accordance with a site-specific survey plan that was submitted to and approved by the NRC (ORISE 2007a). The site-specific survey plan follows the guidance provided in the IEAV Survey Procedures and Quality Program Manuals (ORISE 2008a and ORAU 2007).In the Auxiliary Building, ORISE performed confirmatory survey activities on structural surfaces in Rooms 10, 15, 40, 42, 51, 52, the 51 and 52 Excavation, and in the Pump Alley (Figures 3 through 15). ORISE performed survey activities on the interior surfaces within two Acid Waste System drains (Figures 16 and 17) and two Rad Waste System drains (Figure 18). At the request of the NRC site representative, ORISE also performed confirmatory radiological surveys Of the Fuel Storage Building exterior excavation (Figure 19).SURFACE SCANS Auxiliary Building Structural Surfaces Gamma surface scans ware performed using sodium iodide, thallium-activated

[NaIfl)] gamma scintillation detectors coupled to ratemeters with audible indicators.

Beta surface scans were Rancho Seco Nuclear Generating Station 1695-SR-03-1 performed using large area gas proportional, hand-held gas proportional, and Geiger-Muller (GM)detectors coupled to ratemeter-scalers with audible indicators.

Particular attention was given to cracks, joints, embedded piping openings and horizontal surfaces ,in the evaluated structural surfaces where material may have accumulated.

Drains and Pipe Penetrations Limited qualitative gamma scans were performed in portions of two Acid Waste System drain lines and in two Rad Waste System drain lines. Gamma scans were performed using a cesium iodide, thallium-activated

[CsI(Tl)]

gamma scintillation detector coupled to a ratemeter with an audible indicator.

The detector was also paused at each one-foot scan increment and the gamma count rate recorded.

These data were used for direct comparison with the SMUD FSS data.Pump Alley and Fuel Storage Building Exterior Excavation Areas Gamma scans of the soils within the excavated Pump Alley and the Fuel Storage Building exterior excavation were performed using a NaI(T1) gamma scintillation detector coupled to a ratemeter with an audible indicator.

Beta surface scans of the Pump Alley concrete side walls were performed using hand-held gas proportional detectors coupled to ratemeter-scalers with audible indicators.

SURFACE ACTIVITY MEASUREMENTS Based on beta and gamma surface scan results, direct measurements for beta activity were performed at 59 judgmentally-selected locations on the evaluated structural surfaces within the Auxiliary Building which were available for confirmatory survey activities; 11 direct measurement locations were performed within the Pump Alley. Direct measurements were performed using hand-held gas proportional detectors coupled to ratemeters-scalers.

A smear sample for determining removable gross alpha and gross beta activity levels was collected from each direct measurement location.

Direct measurement and smear locations are indicated on Figures 3 through 14.SOIL SAMPLING ORISE collected four soil samples based on gamma scan results during the initial confirmatory survey activities of the Pump Alley soil excavation in.April 2008. SMUD personnel performed gamma spectroscopy on several of the samples and determined that the soil derived concentration guideline levels (DCGLs) were exceeded and that further remedial actions would be required.ORISE returned the four Pump Alley soil samples to SMUD personnel as additional confirmatory survey activities of the Pump Alley would be required.

ORISE collected two judgmental soil samples from the Fuel Storage Building exterior excavation during the April 2008 survey activities (Figure 19). ORISE collected three judgmental soil samples from the Pump Alley excavation during the May 2008 survey activities (Figure 15).SAMPLE ANALYSIS AND DATA INTERPRETATION Radiological data and sample media were returned to the ORISE laboratory in Oak Ridge, Tennessee for analysis and interpretation.

Radioassays were performed in accordance with the ORISE Laboratory Procedures Manual (ORISE 2008b). The soil samples were analyzed by gamma Rancho Seco Nuclear Generating Station 1695-SR-03-1 spectroscopy for the primary radionucides-of-concern (ROC), cobalt-60 (Co-60) and cesium-137 (Cs-137).

However, spectra were also reviewed for additional gamma-emitting fission and activation products associated with the RSNGS and other identifiable total absorption peaks. The soil sample results were reported in units of picocuries per gram (pCi/g). Smear samples were analyzed for gross alpha and gross beta activity using a low-background gas proportional counter. Smear results and direct measurements for total surface activity were converted to units of disintegrations per minute per 100 square centimeters (dpm/100 cm 2). Embedded piping scan data were reported in units of counts per minute (cpm) to compare with SMUD's gross gamma cpm FSS results.FINDINGS AND RESULTS SURFACE SCANS The scan percent coverage and room area classifications are provided in Table 1.Auxilary Building Structural Surfaces Beta and gamma surface scans determined that localized areas of residual elevated beta and gamma radiation were present on floor and lower wall surfaces within the evaluated survey units (SUs).Residual surface activity levels approaching site-specific DCGLs but less than the SU specific design DCGL elevated measurement comparison (DCGLMC) were limited to small areas that were interspersed throughout the rooms.Acid Waste and Rad Waste Drain Systems Gamma scans of the Acid Waste and Rad Waste drains within the evaluated SUs indicated that gamma radiation levels ranged from 400 to 3,700 cpm. For comparison, the CsI(T1) detector background range for the conduits along the east side of the Turbine Building atthe +40 level elevation ranged from 200 to 800 cpm.A comparison of ORISE and SMUD gamma measurement results for the Acid Waste System and Rad Waste System drain lines indicated elevated gamma radiation levels at approximately the same length/depth and levels as reported by SMUD personnel in the preliminary FSS data packages.

The ORISE confirmatory and SMUDgamma measurement ranges are provided in Table 2.Pump Alley and Fuel Storage Building Excavation Areas Gamma scans of the remediated portions of the Pump Alley and Fuel Storage Building exterior excavation areas detected residual elevated gamma radiation levels at several locations within the Pump Alley and did not detect any locations of elevated gamma radiation in the Fuel Storage Building excavation area. Beta scans of the Pump Alley concrete walls indicated several locations of elevated residual beta radiation; these locations were marked for further investigation.

SURFACE ACTIVITY LEVELS Surface activity and removable activity level results are presented in Table 3.Rancho Seco Nuclear Generating Station 3 1695-SR-03-1 Auxiliary Building Structural Surfaces Beta measurements were performed at locations of residual elevated beta and gamma radiation detected during surface scans. Total net beta activity measurements ranged from 270 to 120,000 dpm/100 cm 2.Thirteen of the 59 direct measurements exceeded the DCGL but all were less than the specific SU DCGLEMc. Removable gross alpha and gross beta activity ranged from 0 to 18 and-4 to 650 dpm/100 cm 2 , respectively.

Pump Alley Beta measurements were performed at locations of residual elevated beta and gamma radiation detected during surface scans. Total net beta activity measurements ranged from 6,300 to 52,000 dpm/100 cm 2.Two of the eleven direct measurements exceeded the DCGL but were less than the specific SU DCGLEMc. Removable gross alpha and gross beta activity ranged from 0 to 1 and-2 to 10 dpm/100 cm 2 , respectively.

SOIL SAMPLES The radionuclide concentrations for the two soil samples collected within the remediated portion of the Fuel Storage Building exterior excavated area ranged from -0.01 to 0.00 pCi/g for Co-60 and 0.42 to 0.44 pCi/g for Cs-137. The radionucide concentrations for the three soil samples collected within the remediated portion of the Pump Alley ranged from 0.03 to 1.41 pCi/g for Co-60 and 0.38 to 121 pCi/g for Cs-137. The confirmatory radionuclide concentrations for the soil samples are provided in Table 4.COMPARISON OF SURVEY RESULTS WITH GUIDELINES STRUCTURAL SURFACE ACTIVITY LEVELS The major contaminants identified by SMUD at RSNGS are beta-gamma emitters-fission and activation products-resulting from reactor operation.

Cs-137 and Co-60 have been identified during characterization as the predominant radionuclides present on structural surfaces.

SMUD developed site-specific DCGLs, which were recently approved by the NRC, based on a dose modeling to future occupants not to exceed 25 mrem/year total effective dose equivalent (TEDE) as presented in Section 6 of the LTP (SMUD 2006a and NRC 2007). The DCGLs for surfaces were modified by SMUD to reflect the ratio of radionuclide concentrations (account for the presence of unmeasured contaminants based on contaminant ratios) in the specific SUs that were being evaluated.

The applicable surface activity guidelines for the evaluated structural surfaces for these surveys are provided in Table 5. These DCGLs were provided in the preliminary FSS data packages for each evaluated SU and were derived from the LTP and decommissioning technical basis document (DTBD)-05-015 (SMUD 2006a and b).Confirmatory survey data for Auxiliary Building structural surfaces were compared with the site-specific DCGL for the evaluated Auxiliary Building SUs. Of the 70 direct beta activity measurement results on the concrete structural surfaces, 15 exceeded the Gross Beta DCGL of 43,000 dpm/100 cm 2.Using the gross activity DCGL as determined in DTBD-05-015 (SMUD 2006b) and the area factor determined for each SU, SMUD calculated Design DCGLPMc Rancho Seco Nuclear Generating Station 4 1695-SR-03-1 values which are also provided in Table 5. All confirmatory direct surface activity measurements on the Auxiliary Building structural surfaces in the evaluated SUs were within the site-specific SU DCGLE,,c as provided by SMUD in the preliminary FSS data packages.ACID WASTE AND RAD WASTE DRAIN SYSTEMS Co-60 is the primary ROC within the embedded piping. SMUD has established a dose-based restriction for embedded piping not to exceed 25 mrem/year that assumes a building occupancy scenario within rooms where embedded piping is present. The corresponding modeled DCGL is 100,000 dpm/100 cm 2.SMUD's grouting action level for embedded piping is 21,000 dpm/100 cm 2 (SMUD 2007).ORISE's confirmatory drain line results were not directly compared to the embedded piping DCGL;instead, since ORISE and SMUD used similar CsI(Tl) detectors (Ludlum Model 44-159), ORISE compared gross gamma scan readings with either SMUD's preliminary FSS data package gamma scan results for each surveyed pipe at various depths or with background levels as determined during a previous ORISE confirmatory survey (ORISE 2007b).Confirmatory survey data for the Acid Waste and Rad Waste System drain ines were compared with the preliminary FSS data package gross gamma cpm results. The confirmatory gamma scan results indicated that ORISE gross gamma radiation levels within the drain line pipes were consistent with the SMUD preliminary FSS data package results.SOIL SAMPLES Table 6-5 (Table 6) from the LTP provides the single nuclide DCGLs for soil at RSNGS. The DCGL is 12.6 pCi/g for Co-60 and 52.8 pCi/g for Cs-137 (SMUD 2006a). The Fuel Storage Building exterior excavation area soil sample concentrations were below the respective single radionuclide DCGLs. Two of the three confirmatory soil samples from the Pump Alley were well below the single nuclide DCGL; however, one soil sample (1695S0016 containing 121 pCi/g of Cs-137) exceeded the soil DCGL for Cs-137 but was within the soil DCGLEMc for the SU which was calculated by SMUD to be 189 pCi/g.

SUMMARY

During the period of April 27 through 29 and May 29, 2008, ORISE performed confirmatory radiological survey activities which included beta and gamma surface scans, beta activity direct measurements, and removable gross alpha and gross beta activity measurements on structural surfaces within the Auxiliary Building; gamma scans within Auxiliary Building Acid Waste and Rad Waste drains; and gamma scans and the collection of soil samples from the Pump Alley and Fuel Storage Building excavation areas.Beta and gamma surface scans identified several areas of elevated beta radiation on the structural surfaces of the evaluated SUs within the Auxiliary Building.

Additional investigations of these locations indicated that the mrajority of the elevated radiation levels were attributable to localized areas of residual beta-gamma radiation within the matrix of the concrete media. In general, the elevated surface activity was limited to small areas that were interspersed throughout the rooms.Rancho Seco Nuclear Generating Station 5 1695-SR-03-1 Direct measurements were performed at 70 locations.

Fifteen direct measurements exceeded the site-specific gross beta DCGL but all were within the SU specific design DCGLEMC criteria.

The confirmatory survey results for Rooms 10, 15, 40, 42, 51, 52 and the Pump Alley concrete walls are in agreement with the radiological status of these SUs as presented in the licensee's preliminary FSS data packages.Confirmatory gamma surface scans of the evaluated Auxiliary Building drain systems indicated that the gamma radiation levels were consistent with the results presented in the preliminary FSS data packages for the surveyed drains.The soil sample results from the Fuel Storage Building exterior excavation area were below the individual radionuclide DCGLs and meet the soil release criteria.

One of the three soil samples from the Pump Alley exceeded the soil DCGL for Cs-137; however, this sample was within the SU specific design DCGIF\,{c for Cs-137.Rancho Seco Nuclear Generating Station 6 1695-SR-03-1 FIGURES Rancho Seco Nuclear Generating Station 1695-SR-03-1 1693-001 (2)',ALIFORNIA Ail..............

Ij J+NOT TO SCALEI Figure 1: Location of Rancho Seco Nuclear Generating Station, Herald, California Rancho Seco Nuclear Generating Station 8 1695-SR-03-1 1695-002 (2), TURBINE BUILDING FUEL STORAGE BUIL.DING REACTOR BUILD)ING CHLORINE BUILDING ISFSI WATER TREATMENT PLANT TECHNICAL CENTER SEWAGE TR-EATMENT ARE SWITCH YARD AUXILIARY LI BUILDING T & R BUILDING NOT TO SCALE Figure 2: Plot Plan of the Industrial Area at Rancho Seco Nuclear Generating Station Rancho Seco Nuclear Generating Station 9 1695-SR-03-1 North Wall Figure provided by SMUD.South Wall Floor MEASUREMENT/SAMPLE LOCATI1N N -S Single Point, Floor and Lower Walls NOT TO SCALE Figure 3: Survey Unit F8130101, Room 10 -Direct Measurement and Sample Locations Rancho Sect Nuclear Generating Station 10 1695-SR-03-1

~ C)OeLIStr~I-b9tO9SGOSOUflt~

/nuWI~I 3Z OftJ'I-I o.E 0Z5 0L@ 5 0@410(ý) 1 @ I g 2-@)Ky@ 1°, cTh y~)@ I (ý I @ I @ I @ I @ 19 I-4.-Figure provided by SMUD.MEASUREMENT/SAMPLE N LOCATION S Single Point, Floor and Lower Walls NOT TO SCALE Figure 4: Survey Unit F8130151, Room 15 -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 11 1695-SR-03-1

E Figure provided by SMUD.MEASUREMENT/SAMPLE N LOCATION*# Single Point, Floor and Lower Walls NOT TO SCALE Figure 5

Survey Unit F8130541, Room 40 -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 12 1695-SR-03-1 r'3 ____ X-----------

_ _ _en -2t~I 1 -4..! l1*1'Figure provided by SMUD.MEASUREMENT/SAMPLE LOCATION N*# Single Point, Floor and Lower Walls A 4 Single Point, Upper Surfaces NOT TO SCALE Figure 6: Survey Unit F8130581, Room 42 -Direct Measurement and Sample Locations Rancho Sect Nuclear Generating Station 1 3 1695-SR-03-1 kj~I Figure provided by SMUD.South Wall MEASUREMENT/SAMPLE LOCATION N 4* Single Point, Floor and Lower Walls NOT TO SCALE A # Single Point, Upper Surfaces Figure 7: Survey Unit F8130169, F8130701 and F8130711, Room 51, Section 1 -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 14 1695-SR-03-1 Figure 8: Survey Unit F8130701, Room 51, Section 1, Upper Surfaces -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 15 1695-SR-03-1 123--I~ t~l lj) "K-' H I tEast Wall 240 7 4, tt 1 fi If W North Wall ided by SMUD. i I ASUREMENT/SAMPLE LOCATION Point, Floor and Lower Walls NOT TO SCALE Figure 9: Survey Unit F8130701 and F8130711, Room 51, Section 2 -Direct Measurement and Sample Locations Generating Station 16 1695-SR-03-1 ME/*# Single Rancho Sect Nuclear ELEV 0O ELEV 5'2-Meter Line North Wall Overhead Structure Column West Wall Figure provided by SMUD.MEASUREMENT/SAMPLE N LOCATION A" Single Point, Upper Surfaces NOT TO SCALE Figure 10: Survey Unit F8130721, Room 51, Section 2 -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 17 1695-SR-03-1 Base Elov. 0" Romn 52 Room 51 K 2f2. 7a. 2; 2Zl 23'ii.r RX Wall~E~asfe Figure provided by SMUD.N MEASUREMENT/SAMPLE LOCATION O Single Point, Floor and Lower Walls NOT TO SCALE Figure 11: Survey Unit F8130732, Room 51 and 52 Excavation Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 18 1695-SR-03-1 Figure provided by SMUD.Wall C N MEASUREMENT/SAMPLE LOCATION L* Single Point, Floor and Lower Walls NOT TO SCALE Figure 12: Survey Unit F8130751, Room 52, West of Column N -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 19 1695-SR-03-1 Figure provided by SMUD.N MEASUREMENT/SAMPLE LOCATION iL* Single Point, Floor and Lower Walls NOT TO SCALE Figure 13: Survey Unit F8130761, Room 52, East of Column N -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 20 1695-SR-03-1 Figure provided by SMUJD.4~if I 4.3 I1/4S 4. 1~5~14.'4 '1 4:.9 Ut a ,~11:~ ]5 ~' 3 44 4. *C fl~4 N MEASUREMENT/SAMPLE LOCATION 0 Single Point, Floor and Lower Walls NOT TO SCALE Figure 14: Survey Unit F8130461, Pump Alley -Direct Measurement and Sample Locations Rancho Seco Nuclear Generating Station 21 1695-SR-03-1 777--4 Jt AI iN i7 q1 Figure provided by SMUD.SOIL SAMPLE LOCATION NOT TO SCALE" # Soil Sample Figure 15: Survey Unit F8130421, Pump Alley -Soil Sample Locations Rancho Seco Nuclear Generating Station 22 1695-SR-03-1 I lAC L(; V400 Figure provided by SMUD.I N MEASUREMENT LOCATIONSurveyed Drain NOT TO SCALE Figure 16: Survey Unit F8990521, Acid Waste Drains -Surveyed Drain 4-1-11 Rancho Seco Nuclear Generating Station 23 1695-SR-03-1 9V0 Mlobd L-54I-1 1, Q Fii~Ii J I ii II Figure provided by SMUD.MEASUREMENT LOCATION N -Surveyed Drain NOT TO SCALE Figure 17: Survey Unit F8990521, Acid Waste Drains -Surveyed Drain 4-2-4 Rancho Seco Nuclear Generating Station 24 1695-SR-03-1

• T*Figure provided by SMUD.MEASUREMENT LOCATION N ---c Q Surveyed Drain NOT TO SCALE Figure 18: Survey Unit F8990521, Rad Waste Drains -Surveyed Drains 2-1-9 and 2-1-14 Rancho Seco Nuclear Generating Station 25 1695-SR-03-1 Figure 19: Survey Unit F8130101, Fuel Storage Building Exterior Excavation

-Soil Sampling Locations Rancho Seco Nuclear Generating Station 26 1695-SR-03-1 TABLES Rancho Seco Nuclear Generating Station 1695-SR-03-1 TALE1 SURVEY~ UNI CLSIICTO AN0CNCVRG Auxiliary Building Survey Unit/Rooma Percent Scan Coverage Class Gammna Floor/Lower Wall Beta Floor Beta Lower Wall Beta Upper Surfaces 10 FL and LW 1 100/50 100 50 -b 15 FL 1 100/50 100 60 40 FL and LW 1 100 25 75 ---42 FL and LW 1 100 85 50 ---51 FL and LW 1 50 50 50 51 US 1 .........

5 52 FL and LW 1 75 50 50 51 and 52 Excavation Pump Alley 1 100C 60 Fuel Building Storage 1100c ----Excavation-Refer to Figures 3 through 15 and 19. FL = floor, LW = lower wall and US = upper surfaces.bScans not performed.

cGamma surface soil scans of excavations.

Rancho Seco Nuclear Generating Station 28 1695-SR-03-1 TALE2 DrIn Lin Dimee Scan Length Gamma Scan Range (cpm) j Location (inches)(feet)I ORISE I SMUD Turbine Building Backgroundsa Conduit, East Side 1 4 1 300 to 6,00 ---Conduit, East Side 2 4 1 300 to 600 ---Conduit, East Side 3 4 1 200 to 600 Conduit, East Side 4 4 1 300 to 600 ---Penetration, East Side 4 1 300 to 600' ---Exciter Pad East 4 12 200 to 800 ---Exciter Pad West 4 12 200 to 800 Background Range --- 200 to 800 Gamma Measurements (cpm)c Auxiliary Building Acid Waste Drainsd 0 400 450 4-1-11 2 1 400 510 2 500 510 3 400 500 4 500 520 5 500 520 6 400 550 7 400 460 8 500 510 9 500 510 10 500 560 11 500 540 12 400 450 13 400 530 14 500 520 15 400 510 16 500 550 17 400 480 18 400 510 19 500 540 20 500 540 21 400 510 i i I Rancho Seco Nuclear Generating Station 29 1695-SR-03-1 TAL 2: ACID WASTE AND RA WASTE DRA~IN YTMGMAMAUEET Drain Line Location Diameter (inches)Scan Length (feet)I Gamma Measurements (cpm)C I ORISE I SMUD Auxiliary Building Acid Waste Drains"0 2,900 2,500 4-2-4 2 1 400 370 2 400 410 3 500 400 4 400 440 5 500 410 6 500 420 7 400 350 8 500 410 9 500 420 10 500 380 11 500 390 12 400 330 13 500 400 14 500 360 15 400 400 16 400 390 17 400 400 18 400 390 19 400 410 20 400 410 21 500 410 22 400 370 Auxiliary Building Rad Waste Drainsd 0 3,100 3,600 1 1,100 2,300 2 700 1,100 2-1-9 6 3 500 800 4 500 1,000 5 900 1,400 6 2,400 2,900 Rancho Seco Nuclear Generating Station 30 1695-SR-03-1 TALE2 AID WASTE AN AT RANSSE AMAMAUEET Drain Line Location Diameter (inches)Scan Length (feet)Gamma Measurements (cpm)c ORISE I SMUD Auxiliary Building Rad Waste Drainsd 7 1,900 2,400 2-1-9 (continued) 6 8 1,100 1,900 9 700 1,400 10 1,000 1,400 11 800 1,300 12 800 1,200 13 800 1,300 14 1,000 1,400 15 1,000 1,500 16 1,000 1,500 17 1,000 1,600 18 1,000 1,600 19 1,100 1,500 20 1,100 1,500 0 800 1,200 2-1-14 4 1 700 1,000 2 700 1,000 3 1,700 2,300 4 1,300 1,700 5 1,400 1,900 6 1,500 1)800 7 700 1,100 8 800 1,000 9 1,000 1,100 10 1,600 2,000 11 1,600 2,200 12 2,900 3,700 13 2,100 3,000 14 3,700 3,700 15 2,600 3,000 16 2,700 2,900 I & I Rancho Seco Nuclear Generating Station 31 1695-SR-03-1 Drain Line Dimtr Scan Len gth Gamma Measurements (cpm) c Location j (inches) (feet) ORISE SMUD Auxiliary Building Rad Waste Drainsd 17 2,500 3,000 2-1-14 18 2,300 2,200 (continued) 19 2,600 3,000 20 2,800 2,900'Turbine Building embedded piping backgrounds were determined within Turbine Building conduits.

This data was collected during a previous ORISE survey (ORISE 2007b).bMeasurements not performed by SMUD within the Turbine Building conduits.cSMUD gamma scan measurement data was provided to ORISE in preliminary FSS data packages or during comparison gamma measurements made with similar gamma detectors.

ORISE'and SMUD results were rounded to two significant digits.dRefer to Figures 16 through 18.Rancho Seco Nuclear Generating Station 32 1695-SR-03-1 TBLE3 Room/ b Locationa Surface" Total Beta Activity (dpm/100 cm 2)c Removable Activity (dpm/100 cm2).Activity Meets Gross Beta.DCGLd Alpha Beta II III Auxiliary Building, Room 10 1 FL 9,800 0 16 YES 2 LW 6,500 0 8 YES 3 FL 7,400 0 8 YES 4 FL 31,000 1 84 YES 5 LW 7,800 0 46 YES 6 LW 9,900 5 190 YES Auxiliary, Building, Room 15 .1 FL 8,700 0 76 YES 2 FL 11,000 1 2. YES 3 FL 11,000 1 6 YES 4 FL 21,000 0 2 YES 5 FL 42,000 1 1 YES AuxiliaryBuilding; Room 40 _______ _ ___ ._1 FL 37,000 0 -4 YES 2 FL 20,000 3 -3 YES 3 TW 14,000 0 -1 YES 4 FL 16,000 0 1 YES 5 LW 30,000 0 14 YES 6 LW 16,000 0 1 YES 7 LW 34,000 0 1 YES 8 LW 27,000 0 -1 YES Auxiliary Building, Room 42 1 FL 53,000 5 110 NO 2 FL 9,500 1 34 YES 3 FL 12,000 0 2 YES 4 FL 8,000 0 -3 YES 5 US 6,600 0 36 YES 6 US 18,000 1 12 YES Rancho Seco Nuclear Generating Station 33 1695-SR-03-1 TBLE3 Room/Locationa Surfaceb Total Beta Activity (dpm/100 cm 2)c Removable Activity (dpm/100 cm 2)Alpha I Beta Activity Meets Gross Beta DCGLd Auxiliary Building, Room 51 1 US 75,000 0 5 NO 2 US 270 1 4 YES.3 US 11,000 9 63 YES 4 US 3,400 0 7 YES 5 US 510 0 1 YES 6 US 4,300 0 6 YES 7 US 75,000 13 210 NO 8 US 5,500 0 3 YES 9 US 120,000 0 46 NO 10 US 31,000 0 10 YES 11 US 55,000 3 140 NO 12 US 4,500 0 -4 YES 13 FL 28,000 0 3 YES 14 FL 18,000 3 -2 YES 15 FL 63,000 0 2 NO 16 FL 9,200 1 3 YES 17 FL 6,500 3 -1 YES.18 FL 32,000 0 6 YES 19 FL 65,000 1 16 NO 20 FL 21,000 0 1 YES 21 LW 27,000 0 1 YES 22 LW 51,000 0 6 NO 23 LW 15,000 18 290 YES 24 LW 55,000 7 650 NO 25 LW 22,000 1 1 YES Rancho Sec6 Nuclear Generating Station 34 1695-SR-03-1 TALE3 ISURFACE A TIVITY LEVELSr Roomu/ra ' Total Beta Location' Surface Activity Loa Ion (dpm/100 cm 2)c (dpemovarne aCtMV)ty (dpm/100 cm 2).tictlVlry ivxeets Gross Beta DCGLd Alpha I Beta Auxiliary Building, Room 52 1 FL 56,000 0 14 NO 2 FL 10,000 0 -2 YES 3 FL 54,000 0 -1 NO 4 FL 35,000 0 3 YES 5 FL 13,000 3 -1 YES 6 FL 27,000 0 -3 YES 7 LW 61,000 5 200 NO 8 LW 64,000 0 190 NO 9 LW 14,000 0 18 YES Auxiliary Building, Pump Alley 1 LW 31,000 0 10 YES 2 LW 31,000 0 8 YES 3 LW 6,300 1 -2 YES 4 LW 52,000 0 7 NO 5 LW 45,000 0 1 NO 6 LW 10,000 1 1 YES 7 LW 11,000 0 4 YES 8 LW 12,000 0 2 YES 9 LW 13,000 0 1 YES 10 LW 10,000 0 10 YES 11 LW 15,000 0 8 YES aRefer to Figures 3 through 14.bStructural surfaces; FL = floor, LW = lower wall, TW = trench wall and US = upper surfaces.cDirect measurement results rounded to two significant digits.dIDCGL values are provided in Table 5. All surface activity measurements that were greater than the gross beta DCGL were less than the design DCGLs determined for each specific survey unit.Rancho Seco Nuclear Generating Station 35 1695-SR 1 RADINUCID COCNRAIN IN SOI SAPE Si Sample Location-Co-6O us-137 Fuel Storage Building Excavation 14 -0.01 +/- 0.0 4 b 0.44 +/- 0.05 15 0.00c +/- 0.04 0.42 +/- 0.05 Pump Alley 16 1.41 +/- 0.13 121 +/- 11 17 0.22 +/- 0.04 15.7 +/- 1.4 18 0.03 +/- 0.06. 0.38 +/- 0.06'Refer to Figures 15 and 19.bUncertainties represent the 95% confidence level based on total propagated uncertainties.

cZero values are due to rounding.Auxiliary Building Class Gross Beta DCGL b .Design DCGLE~cc Survey Unit/Room' (dpm/100 cm2) (dpm/100 cm2)10 FL and LW 1 43,000 224,000 15 FL and LW 1 43,000 152,400 40 FL and LW 1 43,000 141,900 42 FL and LW 1 43,000 141,900 51 FL and LW 1 43,000 154,800 51 US 1 43,000 150,500 52 FL and LW 1 43,000 154,800 51 and 52 Excavation 1 43,000 176,300 Pump Alley LW 1 43,000 153,300'Refer to Figures 3 through 14. FL = floor, LW = lower wall and US = upper surfaces.bGross beta DCGL accounts for radionuclide fractions and hard to detects as specified in the DTBD-05-15 (SMUD 2006b).cDCGLI.ic provided by SMUD and accounted for area factors determined for each specific survey unit.Rancho Seco Nuclear Generating Station 36 1695-SR-03-1 I I S'STABLE 6: Radionuclide Peak of the Mean Dose (mrem/y per pCi/g)DCGIw (pCi/g)C-14 2.93E-06 8.33E+06 Co-60 1.93E+00 1.26E+01 Ni-63 1.60E-06 1.52E+07 Sr-90 3.76E-03 .6.49E+03 Cs-134 1.09E+00 2.24E+01 Cs-137 4.62E-01 5.28E+01-Table 6-5 from the License Termination Plan (SMUD 2006a).Rancho Seco Nuclear Generating Station 37 1695-SR-03-1 REFERENCES Oak Ridge Associated Universities (ORAU). Quality Program Manual for the Independent Environmental Assessment and Verification Program. Oak Ridge, Tennessee; November 1, 2007.Oak Ridge Institute for Science and Education (ORISE). Final Confirmatory Survey Plan for the Remaining Structural Surfaces, Embedded Piping, Standing Water and Open Land Area Survey Units, Rancho Seco Nuclear Generating Station, Herald California

[Docket No. 50-312; RFTA No. 06-003]. Oak Ridge, Tennessee; August 10, 2007a.Oak Ridge Institute for Science and Education.

Revised-Confirmatory Survey Report for Portions of the Auxiliary Building Structural Surfaces and Turbine Building Embedded Piping, Rancho Seco Nuclear Generating Station, Herald, California.

DCN 1695-SR-01-1.

Oak Ridge, Tennessee; December 21, 2007b.Oak Ridge Institute for Science and Education.

Survey Procedures Manual for the Independent Environmental Assessment and Verification Program. Oak Ridge, Tennessee; May 1, 2008a.Oak Ridge Institute for Science and Education.

Laboratory Procedures Manual for the Independent Environmental Assessment and Verification Program. Oak Ridge, Tennessee; March 3, 2008b.Sacramento Municipal Utility District (SMUD). License Termination Plan, Rancho Seco Nuclear Generating Station, Herald, California; April 2006a.Sacramento Municipal Utility District.

Decommissioning Technical Basis Document:

Structure Nuclide Fraction and DCGLs. DTBD-05-015, Revision 0. Rancho Seco Nuclear Generating Station, Herald, California; June 2, 2006b.Sacramento Municipal Utility District.

Decommissioning Technical Basis Document:

Embedded Piping Scenario and DCGL Determination Basis. DTBD-05-009, Revision No. 1.0. Rancho Seco Nuclear Generating Station, Herald, California; June 1, 2007.U.S. Nuclear Regulatory Commission (NRC). Letter from J. Hickman (NRC-HQ) to S. Redeker (SMUD); SUBJECT; Rancho Seco Nuclear Generating Station -Issuance of Amendment RE: License Termination Plan (TAC No. J52668). Washington, DC; November 27, 2007.Rancho Seco Nuclear Generating Station 38 1695-SR-03-1