ML061530421

In-Process Inspection Survey Results for the Remaining Spent Fuel Pool and Northeastern Upper RCA Yard Excavations and Concrete Structures within the Excavations at the Yankee Nuclear Power Station, Rowe, Massachusetts (Docket No 50-29; Rft

ML061530421
Person / Time
Site:	Yankee Rowe
Issue date:	03/13/2006
From:	Adams W Oak Ridge Institute for Science & Education
To:	John Hickman NRC/NMSS/DWMEP
References
RFTA 05-008
Download: ML061530421 (14)

Text

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• r I I RECEIVED 0 -1Eh I S T E RYicy 1 OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION Mi-. John Hickman Division of Waste Management and Environmental Protection U.S. Nuclear Regulatory Commission Two White F h t North " L "-- .' ,~

Mail Stop: 7F27 11545 Rochde Plke Rockville, M D 20852-2738

SUBJECT:

IN-PROCESS INSPECTION SURVEY RESULTS FORTHE REMAINING SPENT FUEL POOL AND NORTHEASTERN UPPERRCAYARD EXCAVATIONS AND CONCRETE STRUCTURES WITHIN THE EXCAVATIONS AT THE YANKEE NUCLEAR POWER STATION, R O W ,

MASSACHUSETTS [DOCKET NO. 50-29; RFTANO. OS-0081

Dear Mi-. Hickman:

The Oak Ridge Institute for Science and Education (ORISE) performed in-process confirmatory inspection survey activities on the remaining Spent Fuel Pool (SFP) and Northeastern Upper RCA Yard excavations at the Yankee Nuclear Power Station in Rowe, Massachusetts during the period of December 6 and 7,2005. These survey activities were requested and approved by the U.S. Nuclear Regulatory Commission (NFKJ. At the request of the NRC site representative, ORISE also performed cwsorysurvey activities on the remaining concrete structures in these areas. Enclosed are the in-process surveyresults documenting these survey activities. The survey activities included gamma surface scans and soil sampling within the excavations and beta surface scans and direct measurements for total net beta activity on the remaining concrete surfaces.

If you have any questions or comments, please direct them to me at 865.576.0065 or J. Scott Kirk at 865.574.0685.

Wade C. Adam Health Physicist/Project Leader Survey Projects WCArar Enclosure C: T. McLaughlin, NRO'NMSS/"WFNT-7El8 E. Abelquist, ORISE E. Knox-Davin, NRO'NMSS/TWFN 8A23 S. Kirk, ORISE J. Kottan, NRC/Region I File/ 1672 Distribution approval a n d concurrence: Initials Technical Management Team Member \F-K Laboratory Manager RPC w t y Manager f2.T Voice: 865.576.0056 Fax: 865.241.3497 E-mad: AdamsW@ orau.gov

IN-PROCESS INSPECTION SURVEY RESULTS FOR THE REMAINING SPENT FUEL POOL AND NORTHEASTERN UPPER RCA YARD EXCAVATIONS AND CONCRETE STRUCTURES WITHIN THE EXCAVATIONS AT THE YANKEE NUCLEAR POWER STATION ROWE, MASSACHUSETTS INTRODUCTION The U.S. Nuclear Regulatoiy Commission (NRC) requested that the Oak Ridge Institute for Science and Education (ORISE) perform an in-process inspection survey of the remaining Spent Fuel Pool (SFP) and Northeastern Upper RCA Yard Excavations suivey units (SU) at the Yankee Nuclear Power Station (YNPS). While on site, the NRC site representative also requested that ORISE perform cursory survey activities on the remaining concrete structures (pedestals and walls) w i h these excavations. The in-process inspection surveys were performed during the period of December 6 and 7,2005.

PROCEDURES In-process inspection surveys were performed in accordance with a site-specific survey plan that was submitted to and approved by the NRC (ORISE 2005a). The site-specific survey plan follows tlie guidance provided in the ORISE Survey Procedures and Quality Assurance Manuals (ORISE 2004 and 2005b).

Remaininp Concrete Structures Beta surface scans were performed using Geiger-Muller (GM) pancake detectors coupled to ratemeter-scalers with audlble indicators. Surface scans were performed on up to 60% of the remaining concrete surfaces. Particular attention was given to cracks, joints, and scabbled areas in the evaluated structural surfaces where material may have accumulated. Direct measurements for total net beta activity were performed at ten locations on the concrete structures whch were available for in-process survey activities. At the discretion of the NRC site representative, smear samples were not deemed necessaiy. Figures 1 through 10 are digital photographs indicating the portions of the remaining pedestals and walls that were part of these survey activities. Locations where direct measurements were taken are indicated on these figures.

NOL-05-02 and NOL-01-04 Excavations Garnma surface scans were performed on up to 80% of accessible portions of the two SU soil excavations using sodium iodide (Nag scintillation detectors coupled to ratemeters with audible indicators. Soil samples were collected from three locations in NOL-05-02 and six locations in NOL-01-04. Figures 11 and 12 indlcate the soil excavation survey units that were part of these survey activities. Locations where soil samples were taken axe indicated on these figures.

SAMPLE ANALYSIS AND DATAINTERPRETATION Radiological data and sample media were returned to ORISEs laboratoiy in Oak Ridge, TN for analysis and interpretation. Radloassays were performed in accordance with tlie ORISE Laboratoiy Yankee Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection Survey Results

Procedwres Manual (ORISE 2005~).Soil sarnples were analyzed by gamma spectroscopy for the primary radionuclides-of-concern (ROC (i.e., CO-60 and Cs-137)]. However, spectla were also reviewed for additional gamma-emitting fission and activation products associated with the YNPS and other identifiable total absoiption peaks, Soil sample results were reported in units of picocuries per gram (pCi/g). Direct measurement data were converted to units of disintegrations per minute per 100 square centimeters (dpm/100 cm?.

FINDINGS AND RFSULTS Remaininp Concrete Structures Beta surface scans did not identify any areas of elevated activity on the remaining concrete suxctures. Total net beta activity measurements ranged from -600 to 900 dpm/l00 cm. A complete listing of the surface activity level results is presented in Table 1.

NOL-05-02 and NOL-01-04 Excavations Gamma surface scans identified four locations of elevated direct gamma rahation on the soil surfaces in SU NOL-01-04 and none in SU NOL-05-02. ORISE collected three soil samples from the SU NOL-05-02 and six soil samples from SU NOL-01-04. Three of the six samples from NOL-01-04 were from three of the four elevated h e c t gamma radlation locations identified during the gamma surfaces scans. ORISE requested that the three soil samples from the elevated l r e c t gamma radmion locations be analyzed by the on-site Yankee Atomic Electric Company (YAEC) radioanalytical laboratory and the results ranged from 12 to 309,000 pCi/g of CO-60and 78 to 1,200,000 pCi/g of Cs-137. Further investigations by the licensee and by the ORISE laboratoiy indicated that the eIevated gamma activity was attributable to discrete particles within the soil matrices of the samples. The ranges of radionuclide concentrations for the six soil samples collected by ORISE (without discrete particles in the samples) were 0.01 to 0.10 pCi/g for CO-60and 0.01 to 0.07 pCi/g for Cs-137. The radloactivity w i k the discrete particles for Samples 29,31 and 32 ranged from -2.7 x to 1.41 pCi for Co-60 and 7.5 x l o 4to 1.41 pCi for Cs-137. A complete listing of the soil sample and discrete particle results is presented in Table 2.

SUMMARY

Since this was an in-process confirmatoiy suivey, the licensee did not have fmal status sumey (FSS) data avadable for review. YNPS personnel provided prelirmnary direct measurement and soil sample results to ORISE while on site.

Beta surface scans dld not identify any areas of elevated beta activity on the remaining concrete structural surfaces within the excavations. Direct measurements were performed at ten locations and all results were well within the derived concentration guideline levels (DCGLs) for CO-60 and Cs-137 as provided in the License Termination Plan FTP (YAEC 2004)]. The h e c t measurement results were also w i k the gross beta activity DCGL as determined by YAEC personnel. Therefore, the results of the survey activities for the remaining concrete structural surfaces confamed that the radiological conditions were suitable for unrestricted use in accordance with cleanup criteiia cited in the licensees LTP.

Gainma surface scans identified four locations of eIevated direct gamma radiation within the NOL-01-04 soil excavation. ORISE personnel collected soil samples from three of the four locations and Yankee Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection Survey Results 2

had the samples analyzed bythe YAEC on-site laboratoryin the presence of ORISE personnel. The YAEC analytical results exceeded the site DCGL's for (3-60 and (3-137. The fourth location identified by ORISE was remediated by YAEC personnel; a discrete particle exceeding DCGL values was identified by YAEC. ORISE collected six additional samples from judgmentally- selected locations. Gamma spectroscopy results for the six samples indicated that the ROC'S were well below the DCGL's while the results for the three discrete particles indicated Co-60 and Cs- 137 activity at up to 1,400,000 pci, each.

The in-process confirmatorysurveys determined that detectable activity, in excess of the soil DCGLs, was present in four soil samples within the Northeastern Upper RCA Yard Excavation.

Therefore, the results of the survey activities for the soil excavations failed to confirm that the radiological conditions were suitable for unrestricted use in accordance with clean up criteria cited in the licensee's LTP.

Yankee Nuclear Power Station 3 1672\Repom\2006 13 In-Process Inspection SurveyResults

Figure 1:BRTO1-12 Facing North-Direct Measurement Location #1 Figure 2 NSY12-01 East Side of Pedestal-Direct

1. Measurement Location 2 Yankce Nuclear Power Station 4 1672\Reports\2006-03-13 In-Process Inspection Sunfey Results

Figure 3: NSY12-01 South Side of Pedestal-Direct Measurement Location # 3 Figure 4 BRTO1-13 West Top of Block-Direct

1. Measurement Location 4 Yankee Nuclear Power Station 5 lG72\Reports\2006-03-13 In-Process Inspection Survey Results

Figure 5: BRTO1-13 Top of Block-Direct Measurement Location #5 Figure 6: SVCO1-18 West Side-Direct Measurement Location #6 1672\Reports\2006-03-13 In-Process Inspection Suncy Rcsults Yankee Nuclear Power Station 6

Figure 7: SVCO1-18 West Side-Direct Measurement Location #7 Figure 8: SVCO1-18 South Side-Direct Measurement Location #8 Yankcc Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection SunTey Rcsults 7

Figure 9: SVCO1-18 South Side-Direct Measurement Location #9 Figure 10: SVCO1-18 South Side-Direct Measurement Location #10 Yankee Nuclear Power Station 8 1672\Reports\2006-03-13 In-lrocess Inspection Sun-ey Results

1672-008 (1) 21 R

MEASUREMENT/SAR/IPLING LOCATIONS N

\

1. SURFACESOIL FEET 0 24 I

8 METERS FIGURE 11: Yankee Nuclear Power Station, Survey Unit NOL-05 Measurement and Sampling Locations Yankee Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection SurveyResdts 9

1672-007 (1) 34 I

MEASUREMENT/SAMPLING LOCATIONS N

\

1. SURFACESOIL FEET n 24 I

8 METERS FIGURE 12: Yankee Nuclear Power Station, Survey Unit NOL-01 Measurement and Sampling Locations 1672\Repo1t~\2006-03-13 In-Process Inspection Survey Resdcs Yankee Nuclear Power Station 10

TABLE 1 SURFACE ACTIVITY LEVELS REMAINING CONCRETE STRUCTURES YANKEE NUCLEAR POWER STATION ROWE, MASSACHUSETTS Total Net Beta Activity Location" (dpd100 cm2) 1 -300 k l , l O O b 2 600 k 1,200 3 900 k 1,200 4 300 f 1,200 5 -600 k 1,000 6 -100 k 1,100 7 200 k 1,100 8 0

• 1,100 9 -600 2 1,000 10 -300 k 1,200 Yankee Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection Survey Results 11

TABLE 2 RADIONUCLIDE CONCENTRATIONS IN SOIL AND DISCRETE PARTICLE SAMPLES REMAINING SPENT FUEL POOL AND NORTHEASTERN UPPER RCA YARD EXCAVATIONS YANKEE NUCLEAR POWER STATION ROWE, MASSACHUSETTS co-60 cs-137 Soil Samples (pci/g)b 1672S0026 0.03 i: 0.04' 0.07 k 0.04 1672S0027 I 0.04 2 0.03 I 0.05 f 0.02 1672S0028 I 0.02 k 0.03 I 0.02 2 0.03 I

~

1672S0030 I 0.01 2 0.03 0.01 i: 0.02 1672S0033 I 0.10 & 0.06 I 0.06 & 0.03 1672S0034 I 0.03 f. 0.03 I 0.05 f 0.02 1

~~~ ~~

Discrete Particle Samplesd (pCi 1672S0029 0.56 i: 0.02 7.5 1 0 .i~: 9.7 1672S0031 -2.7 2.5 1.41 -t 0.14 1672S0032 I 1.41 f. 0.41 I 0.10 f. 0.01 aRefer to Figures 11 and 12.

bThe LTP DCGL values are 3.0 pCi/g for Cs-137 and 1.4 pCi/g for co-60.

CUncertainties represent the 95% confidence level, based on total propagated uncertainties dData are quahfied. Geometries have not been established for this type of sample.

Yankee Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection Survey Results 12

REFERENCES Oak Ridge Institute for Science and Education (ORISE). Survey Procedures Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; September 2,2004.

Oak Ridge Institute for Science and Education. Proposed-In-Process Survey Plan for the Remaining Spent Fuel Pool and Northeastern Upper RCA Yard Excavations, Yankee Nuclear Power Station, Rowe, Massachusetts pocket No. 50-29; RFTA No. 05-0081. Oak Ridge, Tennessee; December 1,2005a.

Oak Ridge Institute for Science and Education. Quality Assurance Manual for the Environmental Survey and Site Assessment Program. Oak fidge, Tennessee; July 28,2005b.

Oak Ridge Institute for Science and Education. Laboratory Procedures Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; June 20,2005~.

Yankee Atomic Electric Company (YAEC). Yankee Atomic Electric Company (YAEC) License Termination Plan &Ifor ) the Yankee Nuclear Power Station (YNPS). Revision 1. Rowe, Massachusetts; November 2004.

Yankcc Nuclear Power Station 1672\Reports\2006-03-13 In-Process Inspection Sunrcy Results 13