ML061800239
| ML061800239 | |
| Person / Time | |
|---|---|
| Site: | University of Virginia |
| Issue date: | 08/23/2005 |
| From: | Bauer T Oak Ridge Institute for Science & Education |
| To: | Dragoun T Division of Regulatory Improvement Programs |
| References | |
| DE-AC05-00OR22750, Job Code J-3036, Task No. 2.10 ORISE 05-1219 | |
| Download: ML061800239 (49) | |
Text
H O RI S E OAK RIDE INSTITUTE FOR SCIENCE AND EDUCATION August 23, 2005 Mr. Thomas Dragoun NRR/DRIP U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406
SUBJECT:
REVISED FINAL REPORT-CONFIRMATORY SURVEY OF THE UNIVERSITY OF VIRGINIA REACTOR, UNIVERSITY OF VIRGINIA, CHARLOTTESVILLE, VIRGINIA [DOCKET NO. 50-62; TASK NO. 2.10]
Dear Mr. Dragoun:
The Environmental Survey and Site Assessment Program (ESSAP) of the Oak Ridge Institute for Science and Education (ORISE) performed confirmatory survey activities of the University of Virginia Research Reactor in Charlottesville, Virginia during the period March 8 to 10, 2005.
Enclosed is the subject revised final confirmatory survey report with NRC/NRR comments incorporated.
If you have any questions please contact me at (865) 576-3356 or Alex J. Boerner at (865) 574-0951.
Sincerely, Timothy J. Bauer Health Physicist Environmental Survey and Site Assessment Program TJB:ar Enclosure cc: A. Adams, NRC/NRR/OWFN 12G13 E. Abelquist, ORISE/ESSAP S. Adams, NRC/NRR/OWFN 012E5 A. Boemer, ORISE/ESSAP W. Eresian, NRC/NRR/OWFN 012G13 File/0981 D. Hughes, NRC/NRR/OWFN 012G13 P. 0. BOX 117, OAK RIDGE, TENNESSEE 37831-0117 Operated by Oak Ridge Associated Universities for the U.S. Department of Energy
to REVISED FINAL REPORT CONFIRMATORY SURVEY OF THE UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA to T. J. BAUER Prepared for the U.S. Nu clear Regulatory Commission Office o0f Nuclear Reactor Regulation Agendes and their conractors; other requests shall appmved by the ouiginating faclity or higher DOE programmatic authority.
The Oak Ridge Institute for Science and Education (ORISE) is a U.S. Department of Energy facility focusing on scientific initiatives to research health risks from occupational hazards, assess environmental cleanup, respond to radiation medical emergencies, support national security and emergency preparedness, and educate the next generation of scientists. ORISE is managed by Oak Ridge Associated Universities. Established in 1946, ORAU is a consortium of 9 icolleges and universities.
NOTICES The opinions expressed herein do not necessarily reflect the opinions of the sponsoring institutions of Oak Ridge Associated Universities.
This report was prepared as an account of work sponsored by the United States Government. Neither the United States Government nor the U.S. Department of Energy, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe on privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement or recommendation, or favor by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof.
ORISE 05-1219 CONFIRMATORY SURVEY OF THE UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA Prepared by T. J. Bauer Environmental Survey and Site Assessment Program Oak Ridge Institute for Science and Education Oak Ridge, Tennessee 37831-0117 Prepared for the U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation REVISED FINAL REPORT AUGUST 2005 This report is based on work performed under an Interagency Agreement (NRC Fin. No. J-3036) between the U.S. Nuclear Regulatory Commission and the U.S. Department of Energy. Oak Ridge Institute for Science and Education performs complementary work under contract number DE-AC05-00OR22750 with the U.S. Department of Energy.
University of Virginia Reactor projects\981\Reports\2005-08-08 Revised Final Report.doc
CONFIRMATORY SURVEY OF THE UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA Prepared by: *4 4t"..
- x. C' Date: /
PEnvironmental a.J. Bar'r, Health Physicist Survey and Site Assessment Program Reviewed by: C~lj A. Boemer, Acting Survey Projects Manager Date: J le) Oas-Environmental Survey and Site Assessment Program Reviewed by: YO *LA* Date: ?)I2/0 R. D. Condra, Laboratory Manager Environmental Survey and Site Assessment Program
-Reviewed by: ) {JA Date:
A. T. Payne, Quality Manager Environmental Survey and Site Assessment Program Reviewed by: Date:
E. W. Abelquist, Program D66tor Environmental Survey and 9ite Assessment Program University of Virginia Reactor projects\O981\Reports\2005-08-08 Revised Final Report.doc
ACKNOWLEDGMENTS The author would like to acknowledge the significant contributions of the following staff members:
FIELD STAFF T. D. Herrera LABORATORY STAFF R. D. Condra J. S. Cox W. P. Ivey W. F. Smith CLERICAL STAFF D. K. Herrera K. L. Pond A. Ramsey ILLUSTRATORS T. L. Brown T. D. Herrera University of Virginia Reactor projects\0981\Reports\2005-08-08 Revised Final Reportdoc
TABLE OF CONTENTS PAGE List of Figures .................................................................................................................................. ii List of Tables ................................................................................................................................. iii Abbreviations and Acronym s ................................................................................................... iv Introduction and Site History ....................................... ............................................................... 1 Site D escription ............................................................................................................................... 2 Objectives ....................................................................................................................................... 3 D ocument Review ........................................................................................................................... 3 Procedures ....................................................................................................................................... 3 Sam ple Analysis And Data Interpretation ................................................................................. 6 Findings and Results ....................................................................................................................... 7 Com parison of Results with Guidelines ................................................................................... 10 Summ ary ....................................................................................................................................... 10 Figures ........................................................................................................................................... 12 Tables ............................................................................................................................................ 20 References ..................................................................................................................................... 26 Appendices:
Appendix A: Major Instrumentation Appendix B: Survey and Analytical Procedures Appendix C: Summary of Surface Soil Screening Values University of Virginia Reactm i projects\098r\Reports\2005-OS-08 Revised Final Report.doc
LIST OF FIGURES PAGE FIGURE 1: Location of the University of Virginia, Charlottesville, Virginia ..................... 13 FIGURE 2: UVA Reactor First Floor-Measurement and Sampling Locations .................. 14 FIGURE 3: UVA Reactor Mezzanine Floor-Measurement and Sampling Locations ..... 15 FIGURE 4: UVA Reactor Ground Floor, East Areas-Measurement and Sampling L ocations ................................................................................................................ 16 FIGURE 5: UVA Reactor Ground Floor, West Areas-Measurement and Sampling Locations ................................................................................................................ 17 FIGURE 6: UVA Reactor Ground Floor, Reactor Pool Walls-Measurement and Sampling Locations .......................................................................................... 18 FIGURE 7: UVA Reactor Pond-Sampling Locations ........................................................ 19 University of Virginia Reactor UV projects\0981\Reports\2005-08-08 Revised Final Report.doc
LIST OF TABLES PAGE TABLE 1: Surface Activity Levels .................................................................................... 21 TABLE 2: Radionuclide Concentrations in Soil-Interior Locations and Reactor Pond ........ 24 TABLE 3: Radionuclide Concentrations in Soil-Split Samples from Waste Tank Excavation .............................................................................................. 25 University of Virginia Reactor iii projects\J98l\Reports\2005-08-08 Revised Final Report.doc
ABBI9EVIATIONS AND ACRONYM Ei instrument efficiency surface efficiency Etotal total efficiency bi number of background counts in the interval CAVALIER Cooperatively Assembled Virginia Low Intensity Educational Reactor cm centimeter cm, square centimeter cpm counts per minute d' index of sensitivity DCGL derived concentration guideline level DOE U.S. Department of Energy DP decommissioning plan dpm disintegrations per minute dpmo100 cm2 disintegrations per minute per 100 square centimeters ESSAP Environmental Survey and Site Assessment Program FSS final status surveys ISM integrated safety management ISO International Standards Organization ITP Intercomparison Testing Program JHA job hazard analysis keV kiloelectron volt kIn kilometer square meter MAPEP Mixed Analyte Performance Evaluation Program MDC minimum detectable concentration MDCR minimum detectable count rate MeV million electron volts m meter min minute mg 2 milligram mg/cm milligrams per square centimeter mmn millimeter MW megawatt NaI sodium iodide NIST National Institute of Standards and Technology NRC Nuclear Regulatory Commission NRIP NIST Radiochemistry Intercomparison Program NRR Office of Nuclear Reactor Regulation ORISE Oak Ridge Institute for Science and Education pCi/g picocuries per gram RAI request for additional information S second University of Virginia Reactor iv projects5981\Repors2005-08-08 Revised Final Reportdoc
ABBREVIATIONS AND ACRONYMS (Continued)
SOF sum-of-fractions TAP total absorption peak UVA University of Virginia UVAR University of Virginia Reactor University of Virginia Reactor V projects\0981\Reports\2005-08-08 Revised Final Reportdoc
CONFIRMATORY SURVEY OFTHE UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA INTRODUCTION AND SITE HISTORY The University of Virginia (UVA) operated the University of Virginia Reactor (UVAR) beginning in 1960 under U.S. Nuclear Regulatory Commission (NRC) License No. R-66 for radiation research, activation analysis, isotope production, neutron radiography, radiation damage studies, and training of nuclear engineering students. The UVAR was a light-water cooled, moderated, and shielded pool-type nuclear reactor. Originally commissioned to operate at a maximum power of one megawatt (MW), it was upgraded in January 1971 to operate at two MW. The original fuel was aluminum clad high-enriched uranium, but was converted to low-enriched uranium in early 1994.
The UVAR was permanently shut down in June 1998 and the fuel was removed by mid 1999.
The integrated power generation of the UVAR was an estimated 2,559 MW-days. A radiological characterization survey was initiated in July 1999, with the report completed in April 2000.
UVA submitted a Decommissioning Plan (DP) to the NRC in February 2000. Decommissioning began in March 2002 with the removal of extraneous fixtures, equipment, and materials, such as the reactor grid plate, reactor support structure, and equipment and activated concrete from the reactor pool. Final status surveys (FSS) were completed and the results presented to the NRC in 2004 (UVA 2000 and 2004a).
The CAVALIER (Cooperatively Assembled Virginia Low Intensity Educational Reactor) was operated in the UVAR facility and separately decommissioned. A FSS was performed and a license termination requested. The CAVALIER facility, NRC License R-123, was added within the scope of the UVAR facility and included in the FSS (UVA 2004a).
The NRC's Headquarters Office of Nuclear Reactor Regulation (NRR) requested that the Oak Ridge Institute for Science and Education's (ORISE) Environmental Survey and Site Assessment Program (ESSAP) perform confirmatory surveys of the UVAR facility.
University of Virginia Reactor projects\0981\Reports\2005-08-08 Revised Final Report.doc
SITE DESCRIPTION The UVA is located approximately 0.6 kilometers (kIn) west of the city limits of Charlottesville in Albemarle County, Virginia (Figure 1). The UVAR facility is located on the northern grounds of the UVA and includes approximately 2,030 square meters (m2) of interior floor space and 9,390 mi2 of fenced land.
The upper floor (first floor) contains the Reactor Confinement Room (Room 131), which housed the former UVAR in the 9.8 m long by 3.7 m wide by 8.2 m deep reactor pool. This room also held associated operating equipment, systems, and controls and is circular in shape with an elevated ceiling (approximately 10 m). Most of the impacted reactor and support system components were removed for disposal as radioactive waste or free released. Also located on the upper floor are the Instrument Shop (Room 128), the Shipping Area (Room 127), and multiple offices and other support facilities (UVA 2004a).
Below the upper floor is the Mezzanine level which includes the Demineralizer (Room M021),
Mechanical Room (Room M020), HP Laboratory (Room M019), several partially contaminated laboratories (Rooms M005 and M008), and multiple offices and other support facilities for staff and students. A crawl space is accessible from the stairwell. Adjacent to the Reactor Confinement Room, there was a cooling tower located on the roof of the Mezzanine level that provided cooling for the reactor secondary system water (UVA 2004a).
Below the Mezzanine level is the ground floor. This floor contains the Heat Exchanger (Room G024), Rabbit Room (Room G005), Beamport/Experimental Area (Room G020), Hot Cell (Rooms G025, G026, and G027), Counting Room (Room G004), Woodworking and Machine Shop (Room G008), Source Storage (Rooms G007A, G018, and G022), the former CAVALIER Facility (Room G007), and miscellaneous support facilities and areas (UVA 2004a).
The fenced land area included several underground tanks. Two of these tanks were used for collection and holdup of facility discharges containing radioactive contamination and one, located at ground level at the front of the facility, was used during fuel shipments. Exterior construction of the UVAR facility is of metal and concrete block with brick veneer; interior University of Virginia Reactor 2 projects\0981\Reports\2005-08-08 Revised Final Reportdoc
construction includes concrete slab floors and walls of block and drywall (UVA 2000 and 2004a).
OBJECTIVES The objectives of the confirmatory survey were to provide independent contractor field data reviews and radiological data for use by the NRC in evaluating the adequacy and accuracy of the licensee's procedures and final status survey results.
DOCUMENT REVIEW ESSAP reviewed the licensee's FSS plan (UVA 2004b) and report (UVA 2004a) for adequacy and appropriateness taking into account the DP (UVA 2000) and MARSSIM guidance (NRC 2000). Data were evaluated to assure that areas exceeding guidelines were identified and had undergone remediation. Final status survey results were compared with guidelines to ensure that the data had been interpreted correctly.
PROCEDURES ESSAP performed confirmatory surveys of the UVAR during the period March 8 to 10, 2005.
The survey was performed in accordance with the site-specific survey plan submitted to and approved by the NRC and the ORISE/ESSAP Survey Procedures and Quality Assurance Manuals (ORISE 2005a and 2004b and c). Additional information concerning major instrumentation, sampling equipment, and survey and analytical procedures may be found in Appendices A and B.
INTERIOR ESSAP used the following procedures for the interior portions of the survey.
Reference Grid Measurement and sampling locations were referenced to the existing UVA-established grid system.
University of Virginia Reactor 3 projects\0981Reports\2005-08-08 Revised Final Report.doc
Surface Scans Surface scans for beta and gamma radiation were performed over selected areas of the UVAR facility as summarized in the table below. Survey areas included areas with high potential for residual contamination exceeding release criteria, such as the Reactor Confinement Room (Room 131) and adjacent rooms used for reactor operations and laboratories where radionuclides were used during experiments.
Surface Scan Coverage for UVAR Facility Area Beta and Gamma Radiation Floors Lower Walls Upper Walls and Ceilings Reactor Confinement Room 50% a (Room 131)
Reactor Pool 75% 5-10%
Former HP Lab (Rooms M005 and 50%
M005A) 100% 5%
Former Hot Lab (Room M008) 75%
Demineralizer Room (Rooms M021 25%
and M021A)
Rabbit Room (Room G005)
CAVALIER Facility (Room G007) 10%
Heat Exchanger Room (Room G024) 75%
Hot Cell (Rooms G025, G026, and 50-100% 25-50%
G027) 50-100% 25-50%
'Not performed Particular attention was given to remediated and adjacent surfaces, cracks and joints in the floors and walls, and other locations where residual radioactive material may have accumulated. In addition to surfaces, the boreholes UVA installed into the reactor pool floor were gamma scanned. Scans were performed using gas proportional and Nal scintillation detectors coupled to ratemeters or ratemeter-scalers with audible indicators. Locations of elevated direct radiation were noted for further investigation.
Surface Activity Measurements UVA did not determine construction material-specific backgrounds for correcting surface activity measurements to account for contributions from naturally occurring materials. Instead, UVA performed a shielded and unshielded measurement at each location to correct for ambient University of Virginia Reactor 4 projects\0981\Reports\2005-08-08 Revised F'mal Report.doc
gamma background contribution to the measurement count rate. ESSAP direct measurements were corrected for ambient background using the same methodology.
Direct measurements for total beta activity were performed at 60 locations, chosen judgmentally, that included areas of elevated direct radiation identified by surface scans. Dry smears were collected at each direct measurement location for determining removable gross alpha and gross beta activity, except for six locations measured on the upper walls of the reactor pool which were not accessible; direct measurements were performed using an extension pole at these locations.
Direct measurements were performed using gas proportional detectors coupled to ratemeter-scalers. Figures 2 through 6 show measurement locations.
Soil Sampling Sub-surface soil samples were collected in increments of 15 cm from 0 to 30 cm in depth at judgmental locations beneath the floor of the Reactor Confinement Room (Room 131) and reactor pool floor. Sampled locations corresponded to locations UVA made accessible during decommissioning activities. Figure 2 shows the soil sampling locations.
EXTERIOR ESSAP used the following procedures for outdoor portions of the survey area.
Reference Grid Measurement and sampling locations were noted on a UVA-drawn figure of the exterior areas.
Surface Scans Surface scans of outdoor locations, including soil areas where the underground waste tanks were removed and the reactor pond, were performed over approximately 25 to 100% of the accessible areas using a NaI scintillation detector coupled to a ratemeter.
University of Virginia Reactor 5 projects\0981\Reports\2005-08-08 Revised Final ReporLdoc
Soil Samplin2 Surface soil (0-15 cm) and sub-surface soil (in increments of 15 cm from 15 cm depth to 45 cm depth) samples were collected at judgmental locations from the reactor pond. Figure 7 shows the soil sampling locations.
On January 21, 2003, UVA collected soil samples from the waste tank excavation during an NRC inspection. The soil samples were split and the NRC requested UVA to store the NRC's samples until a future date. During this confirmatory survey, the NRC inspector requested that ESSAP analyze a limited number of the split samples. ESSAP chose three of the split samples for which UVA reported positive Cs-137 concentrations, and two additional samples were selected randomly. It should-be noted that UVA did not maintain a record of the chain-of-custody for the NRC's split samples; however, the samples were stored in a container within the UVAR facility and security seals on all of the split samples were intact.
SAMPLE ANALYSIS AND DATA INTERPRETATION Samples and data were returned to ORISE's ESSAP Oak Ridge, Tennessee, facility for analysis and interpretation. Sample analyses were performed in accordance with the ORISE/ESSAP Laboratory Procedures Manual (ORISE 2004d). Dry 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). Soil samples were analyzed by gamma spectroscopy. Spectra were reviewed for identifiable total absorption peaks. Soil sample results were reported in units of picocuries per gram (pCi/g).
Confirmatory survey data were compared with the appropriate regulatory guidelines for release of the site without radiological restrictions. Predominant radionuclides of concern found at the UVAR facility include Co-60 and Cs-137, with lesser amounts of C-14, Fe-55, and Eu-152. The radionuclides present and their relative ratios varied depending on the mechanism of contamination and the medium type. Research projects in labs M005 and M008 included the use of Tc-99 and Ni-63.
University of Virginia Reactor 6 projects\0981\Reports\2005-08-08 Revised Final Report.doc
The UVAR facility derived concentration guideline levels (DCGL) for building surfaces were selected from NRC tables of screening values published in NUREG-1757, Volume 1 (NRC 2003). UVA calculated a gross activity DCGL of 6,320 dpm/100 cm 2, except for laboratories M005 and M008, based on Final Status Survey Plan Addendum 004, Appendix A. UVA calibrated surface activity measurement instrumentation to Tc-99. The contamination in laboratories M005 and M008 was Tc-99 and Ni-63, respectively. UVA selected the gross activity DCGL of 1.3E6 dpm/100 cm 2, based on the more conservative screening value for Ni-63, for these laboratories, and calibrated surface activity measurement instrumentation to Ni-63. Because screening values were selected to demonstrate compliance, UVA elected to not allow areas of elevated activity; therefore, there are no included area factors (UVA 2004a).
Appendix C provides the screening values published in NUREG-1757, Volume 1 (NRC 2003) that UVA must meet for unrestricted release of soil areas. UVA modified these screening values to account for hard to detect radionuclides. The following modified DCGLs are applicable:
3.4 pCi/g for Co-60 in soil from beneath the Reactor Confinement Room (Room 131) and reactor pool as well as soil from the waste tank excavation and 5.9 pCi/g for Cs-137 for the reactor pond soil. These guidelines apply to the upper 15 cm of soil in the waste tank excavation. They also apply to the upper 0 to 1 m of soil from the reactor pond, the soil beneath the Reactor Confinement Room (Room 131), and reactor pool. While soil samples could not be collected down to a full depth of 1 m, the upper sub-surface soils collected represented areas with the highest contamination potential that could be used to identify areas requiring further investigation (UVA 2004a).
FINDINGS AND RESULTS DocuMENT REVIEW ESSAP reviewed the licensee's FSS plan (UVA 2004b) and report (UVA 2004a). Comments ESSAP identified in the project documentation were provided to NRC/NRR (ORISE 2003 and 2004a). UVA's responses to the NRC's Request for Additional Information (RAI) were reviewed and determined to be acceptable (ORISE 2005b). The procedures, methods, and data University of Virginia Reactor 7 projects\0981Reports\2005-08-08 Revised Final Report.doc
submitted by UVA were considered to be appropriate and adequately documented the radiological status of the UVAR facility.
INTERIOR The results for interior surveys are discussed below.
Surface Scans Three areas of elevated beta surface radiation were noted in the reactor pool. One area was found on the lower portion of the gate frame, a second area was a debris pile found on the floor on the northern side, and a third area was located on the southern side. UVA removed the debris pile-follow-up scans did not note any residual elevated beta radiation. Five areas of elevated beta surface radiation were noted in Room M008--each of these areas had been marked by UVA. One area of elevated beta surface radiation was noted on a lower wall in the CAVALIER facility (Room G007). One area of elevated gamma radiation at approximately eight times background was noted in a partial floor core in the concrete of the northern side of the reactor pool. After ESSAP's investigation, a hot particle was removed from the partial floor core. UVA performed a gamma spectroscopy field measurement and identified the contaminant to be Co-60.
UVA hypothesized that this was a residual stainless steel "flea" from underwater cutting operations performed in the 1980s. Two completed reactor floor bore holes had elevated gamma radiation levels ranging from approximately four to eight times background--one borehole was noted as number 10 in the UVA FSS documentation while the other was installed during characterization per on-site discussion with UVA subcontractors. Scans of the remaining surfaces did not identify any additional locations of elevated beta or gamma radiation.
Surface Activity Levels Total and removable surface activity levels are provided in Table 1. Total beta activity levels ranged from -240 to 33,000 dpm/100 cm 2 for all areas., Removable activity levels ranged from 0 to 5 dpmr/100 cm 2 for gross alpha and from -5 to 30 dpm/100 cm 2 for gross beta for all areas.
A summary of the total surface activity results for areas of interest is provided below and includes the gross activity DCGL for each area.
University of Virginia Reactor 8 projects\0981\Reports\2005-08-08 Revised Final Report.doc
UVAR Area Range of Total Beta2Activity Gross Activity DCGL (dpm/100 cm ) (dprn/100 cm 2 )
Reactor Confinement Room (Room 131)(Ro11 6 to 1,300 6,320 Reactor Pool 300 to 4,900 6,320 Former HP Labs (Room -240 to 33,000 1E6 M005, MO05A, and M008)
Remaining Areas 230 to 2,500 6,320 Radionucide Concentrations in Soil Samples Table 2 shows the radionuclide concentrations in soils beneath the Reactor Confinement Room (Room 131) and reactor pool for Co-60, Cs-137, Eu-152, and Eu-154 identified during the analysis of the soil samples by gamma spectroscopy. Radionuclide concentrations in the soils ranged from -0.04 to 2.98 pCi/g for Co-60, -0.02 to 0.12 pdi/g for Cs-137, -0.09 to 0.14 pCi/g for Eu-152, and -0.12 to 0.17 pCi/g for Eu-154. Using the sum-of-fractions (SOF) calculation to compare to the unity rule, as discussed in Section 4.3.3 of MARSSIM (NRC 2000), the SOF values ranged from 0.00 to 0.92. In addition, elevated levels of natural thorium (by Ac-228) and natural uranium (by Th-234) were noted in the reactor pool samples. Concentrations in samples S0006 through S0009 ranged from 3.38 to 6.47 pCi/g for Ac-228 and 1.95 to 4.60 pCi/g for Th-234.
EXTERIOR The results for exterior surveys are discussed below.
Surface scans Gamma surface scans were within the range of ambient background levels.
Radionuclide Concentrations in Soil Samples Table 2 shows the radionuclide concentrations in soils collected from the reactor pond for Co-60, Cs-137, Eu-152, and Eu-154 identified during the analysis of the soil samples by gamma spectroscopy. Radionuclide concentrations in the soils ranged from 0.00 to 5.50 pCi/g for Co-60, 0.00 to 1.67 pCi/g for Cs-137, -0.07 to 8.11 pCi/g for Eu-152, and -0.05 to 0.70 pCi/g for Eu-154. The SOF values ranged from 0.00 to 2.8.
University of Virginia Rewwr 9 projects\0981\Reports\2005-08-08 Revised Final Reportdoc
Table 3 shows the radionuclide concentrations in the NRC's split soil samples from the waste tank excavation for Co-60, Cs-137, Eu-152, and Eu-154 identified during analysis of the soil samples by gamma spectroscopy. Radionuclide concentrations in the soils ranged from -0.01 to 0.01 pCi/g for Co-60, 0.13 to 0.32 pCi/g for Cs-137, -0.07 to 0.02 pCi/g for Eu-152, and -0.09 to 0.13 pCi/g for Eu-154. The SOF values ranged from 0.01 to 0.05. The reported data for UVA's split samples are also reported in Table 3 and were comparable with the ESSAP results.
COMPARISON OF RESULTS WITH GUIDELINES Results of the survey were compared to the applicable guidelines. Confirmatory results for building surfaces were all less than the applicable gross activity DCGLs. One surface soil sample from the reactor pond (0981S0012) exceeded the screening value for Co-60; because this elevated area was not identified during surface scans and the activity exceeding the screening value was only identified in the upper 15 cm of the soil, the sample is not indicative of a large, distributed source but rather a small isolated area. Based on these results and an evaluation of the licensee's data, it is ESSAP's opinion that the soil from 0 to 1 m would meet the individual radionuclide DCGLs and the unity rule. All other confirmatory soil samples and split soil samples from the waste tank excavation met individual radionuclide DCGLs as well as the unity rule. The elevated gamma levels noted in two boreholes in the northern section of the reactor pool floor were caused by the elevated natural thorium and uranium concentrations. These elevated levels were expected for the area per discussions with the licensee staff.
SUMMARY
At the request of the U.S. Nuclear Regulatory Commission, the Environmental Survey and Site Assessment Program of the Oak Ridge Institute for Science and Education conducted confirmatory survey activities for the University of Virginia Reactor in Charlottesville, Virginia.
Confirmatory activities included document and data reviews, and during the period March 8 to 10, 2005, independent surface scans, surface activity measurements, and soil sampling.
University of Virginia Reactm 10 projects\0981\Reports\2005-08-08 Revised Final Report.doc
0 0
0 The findings of the confirmatory survey support UVA's final survey results for building surfaces and soil areas, and in ESSAP's opinion, indicate that the radiological conditions of the surveyed areas satisfy the NRC guidelines for release without radiological restrictions.
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
V p
p V
University of Vixginia Rmtw 11 projects\98l\Reportsm\2005-08-O5 Revised Fimal Reportdoc
)
FIGURES University of Virginia Reactor projects\0981Reports\2005-08-08 Revised Final Report.doc
981-001 (2)
Ir N
NOT TO SCALE FIGURE 1: Location of the University of Virginia, Charlottesville, Virginia University of Virginia Reactor 13 projects\0981\Reports\2005-08-08 Revised Final Reportdoc
981-002 (2)
FIGURE 2: UVA Reactor First Floor - Measurement and Sampling Locations University of Virginia Reactor 14 projects\0981*Reports\2005-08-08 Revised Final Reportdoc
981-003 (1)
A B C D E o HL. 1+0.9 ROOM M021A ROOM M021 7+0. 8s 4+0.3 29 7
4 3 6 5
2 2
1 4 3
0 30 A B C D B F F40.2 2
ROOMS M005 & M005A 1
31 0
A B C D E E+0.1 ROOM MOOS I
N MEASUREMENT/SAMPLING LOCATIONS
- # SINGLE-POINT D SURVEYED AREA LOWER WALLS AND FLOOR NOT TO SCALE I ________________________________ L FIGURE 3: UVA Reactor Mezzanine Floor - Measurement and Sampling Locations University of Virginia Reactor 15 projects\0981\Reports\2005-08-08 Revised Final Report.doc
981-004 (1) 5340 C
A
/4ý B C 541 I D E 0 H I I J+0.8 ROOM G024 4.3 4+0-3 4
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oil 0
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MEASUREMENT/SAMPLING LOCATIONS E SURVEYED AREA LW#SINGL LAPOINT k INACCESSIBLE AREA LOWER WALLS AND FLOOR NOT TO SCALE FIGURE 4: UVA Reactor Ground Floor, East Areas - Measurement and Sampling Locations University of Virginia Reactor 16 projects\0981\Reportso2005-08-08 Revised Final Report.doc
981-005 (1)
Rabbit Room CAVALIER
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6O 4
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591 A B C D E E+0.75 6 ROOM G005 4
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MEASUREMENT/SAMPLING LOCATIONS
- SINGLE-POINT l SURVEYED AREA LOWER WALLS AND FLOOR NOT TO SCALE I I FIGURE 5: UVA Reactor Ground Floor, West Areas - Measurement and Sampling Locations University of Virginia Reactor 17 projects\098l\Reports\2005-08-08 Revised Final Report.doc
981-006 (1) 0 0 0
-1 - - - -
-1 - - - -
-1
-2 -2
-2
-3 -3
-3
-4 -- - -4
-4
-5 - 4 -5 6 26 ,28
-6 -6
-6
-7 -7
-7 0.35 - 25 _ 0.35 0.35A B C D E1-0.9 E+0.7 E D C B A A B C D E E+0.7 North Pool, North Wall North Pool, East Wall North Pool, West Wall 0 0 0
-I -1 -1
-2 -2 -2
-3 -3 -3
-4 -4 7-S -4 2 3
-5 -5 -5
-6 -6 -6 1 i)20
-7 15- -7 -7
-I -j17 0.35 0.35 0.351 1 A B C D E E D C B A A B C D E South Pool, East Wall South Pool, South Wall South Pool, West Wall N
MEASUREMENT/SAMPLING LOCATIONS
- SINGLE-POINT LOWER WALLS AND FLOOR [] SURVEYED AREA A # SINGLE-POINT UPPER WALLS NOT TO SCALE FIGURE 6: UVA Reactor Ground Floor, Reactor Pool Walls - Measurement and Sampling Locations University of Virginia Reactor 18 projects\0981\Reports\2005-08-08 Revised Final Report.doc
981-006 (1)
N SAMPLING LOCATIONS I
- # SURFACE/SUBSURFACE SOIL I
NOT TO SCALE FIGURE 7: UVA Reactor Pond - Sampling Locations University of Virginia Reactor 19 projects\0981\Reports\2005-08-08 Revised Final Reportdoc
TABLES University of Virginia Reactor projects\0981\Reports\2005-08-08 Revised Final Report.doc
TABLE 1 SURFACE ACTIVITY LEVELS UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA Surfaceb Total Beta Activity Removable Activity Locationa (dpm/1O0cm 2)
(dpm/100 cm 2 )
Alpha 7 -Beta Reactor Confinement Room (Room 131) 39 F 1,300 0 -1 40 F 1,100 0 -2 41 F 820 0 1 42 F 320 1 3 43 F 450 3 7 44 F 890 0 9 45 LW 460 0 -3 46 LW 840 0 -4 47 LW 16 0 3 48 LW .170 0 -1 Reactor Pool 1 UW 1,200 __c --
2 UW 1,100 ..--
3 UW 840 ..--
4 UW 1,400 ..--
5 UW 1,100 ..
6 UW 1,200 -- --
13 F 1,900 0 -4 14 F 1,200 1 10 15 LW 890 0 -3 16 LW 1,200 0 6 17 LW 300 1 6 18 LW 1,800 1 -3 19 LW 1,800 0 -1 University of Virginia Reactor 21 projeets\0981\Reports\2005-O8-08 Revised Final Report.doc
TABLE 1 (Continued)
SURFACE ACTIVITY LEVELS UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA Total Beta Activity Removable Activity eb Locationa Surface (dpm/100 cm )2 (dpMIOOCM2 )
Alpha Beta Reactor Pool - Continued 20 LW 1,100 0 2 21 F 4,400 1 5 22 F 2,100 0 7 23 LW 1,500 0 -2 24 LW 1,100 0 5 25 LW 1,500 0 3 26 LW 1,000 5 -1 27 F 4,900 0 6 28 LW 1,300 3 -5 Former HP Lab (Rooms M005 and M005A) 33 F -240 0 1 34 F 240 3 1 35 LW 790 1 -2 36 LW 1,000 0 6 37 F -48 1 -5 38 LW 790 0 -2 Former Hot Lab (Room M008) 29 F 210 3 1 30 F 2,100 3 3 31 LW 33,000 0 -1 32 LW 1,300 0 3 Demineralizer Room (Rooms M021 and M021A) 49 F 750 0 23 50 F 1,400 1 9 University of Virginia Reactor 22 projects\0981 Reports\2005-08-O8 Revised Final Report.doc
TABLE 1 (Continued)
SURFACE ACTIVITY LEVELS UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA 17 I
Demineralizer Room (Rooms M021 and M021A) - Continued 51 F 490 0 3 52 F 700 1 3 Rabbit Room (Room G005) 58 F 360 0 -1 59 F 230 0 6 60 LW 870 1 2 CAVALIER Facility (Room G007) 55 F 390 0 2 56 F 1,100 0 -4 57 LW 2,500 0 7 Heat Exchanger Room (Room G024) 53 F 1,000 1 2 54 F 1,400 1 30 Hot Cell (Rooms G025, G026, and G027) 7 LW 1,000 0 4 8 F 1,100 0 -1 9 LW 260 1 1 10 F 1,300 3 1 11 LW 1,700 0 1 12 F 1,300 0 2
'Refer to Figures 2 through 6.
bF = floor; LW = lower wall; UW = upper wall.
F- = Measurement not performed.
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TABLE2 RADIONUCLIDE CONCENTRATIONS IN SOIL INTERIOR LOCATIONS AND REACTOR POND UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA ESSAP Sample Depth Radionuclide Concentration (pCi/g) SOFb Number' (cm) I Co-60 Cs-137 Eu-152 Eu-154 Fill Beneath Reactor Confinement Room Floor (Room 131) 0981S0001 0-15 -0.02 +/- 0.03c 0.02 +/- 0.03 0.01 +/-0.06 0.11 +/-0.13 0.02 0981S0002 0-15 0.12 +/- 0.06 0.91 +/- 0.04 -0.01 +/- 0.06 0.03 +/- 0.13 0.04 0981S0003 15-30 0.08 +/- 0.05 0 .0 0 d + 0.02 0.02 +/- 0.06 -0.12 +/- 0.12 0.03 0981S0004 0-15 0.03 +/- 0.03 0.00 +/- 0.02 -0.05 +/- 0.05 0.00 +/- 0.10 0.01 0981SO005 15-30 0.00 +/- 0.03 -0.01 +/- 0.03 -0.01 +/- 0.06 0.05 +/- 0.13 0.01 Soil Beneath Reactor Pool Floor 0981S0006 0-15 0.00+/-0.04 0.02 +/- 0.04 -0.11 +/-0.09 0.06 +/- 0.16 0.01 0981S0007 15-30 -0.04 +/- 0.05 -0.02 +/- 0.04 -0.09 +/- 0.09 -0.01 +/- 0.19 0.00 0981S0008 0-15 2.98 +/-0.14 0.12 +/- 0.03 0.14 +/-0.09 0.17 +/-0.14 0.92 0981S0009 15-30 0.70 +/-0.10 0.03 +/- 0.04 0.10 +/-0.09 -0.11 +/-0.17 0.22 Reactor Pond 0981S0010 0-15 0.04+/-0.05 0.12 +/- 0.03 -0.03 +/- 0.08 0.05 +/-0.15 0.04 0981S0011 15-30 0.00 +/- 0.03 0.00 +/- 0.03 -0.07 +/- 0.07 -0.05 +/- 0.15 0.00 0981S0012 0-15 5.50 +/- 0.25 1.67 +/- 0.13 8.11 +/-0.43 0.70 +/- 0.30 2.8 0981S0013 15-30 0.32 +/- 0.09 0.55 +/- 0.06 0.30 +/- 0.09 0.27 +/- 0.20 0.25 0981S0014 0-15 0.03 +/- 0.05 1.05 +/- 0.07 -0.01 +/- 0.07 -0.03 +/-0.14 0.19 0981S0015 15-30 0.03 +/- 0.04 0.18 +/- 0.06 0.05 +/- 0.09 -0.04 +/-0.16 0.04 0981S0016 30-45 0.01 +/- 0.04 0.08 +/- 0.04 -0.05 +/- 0.07 0.03 +/- 0.16 0.02 "Refer to Figures 2 and 7.
bCalculated using the sum-of-fractions (SOF) to compare to the unity rule, as discussed in Section 4.3.3 of MARSSIM (NRC 2000). Refer to Appendix C for surface soil screening DCGLs. To account for hard to detect radionuclides, UVA applied the following modified DCGLs: 3.4 pCi/g Co-60 in soil beneath the Reactor Confinement Room (Room 131) and reactor pool floor and 5.9 pCi/g Cs-137 for the reactor pond.
- Uncertainties are total propagated uncertainties at the 95% confidence level.
dZero values are due to rounding.
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~-
, ,-.' q~ - - - -- 4F 1 r '.-. -
TABLE 3 01 RADIONUCLIDE CONCENTRATIONS IN SOIL SPLIT SAMPLES FROM THE WASTE TANK EXCAVATION UNIVERSITY OF VIRGINIA REACTOR UNIVERSITY OF VIRGINIA CHARLOTTESVILLE, VIRGINIA ESSAP ESSAP Radionuclide Concentration (pCi/g) UVA Sample UVA Radionuclide Concentration (pCi/g)b Sample SOF4 ID Number Co-60 Cs-137 Eu-152 Eu-154 Co-60 Cs-137 0981S0017 0.01 +/- 0.03c 0.19 +/- 0.04 0.02 +/- 0.06 -0.07 +/- 0.12 0.02 N.VA-WTFS- <0.16 <0.31 N3.6-W23.7 0981SO018 -0.01 +/- 0.04 0.15 +/- 0.05 -0.06 +/- 0.07 0.04 +/- 0.16 0.02 UVA-WTFS1 <0.21 0.28 N3.6-W18.7 0981S0019 0.01 +/- 0.03 0.13 +/- 0.04 -0.04 +/- 0.06 -0.04 +/- 0.20 0.01 UVA-WTFS- <0.12 0.1 LA N0.7-WT1.2 0981S0020 0.01 +/- 0.04 0.32 +/- 0.05 -0.07 +/- 0.07 0.13 +/- 0.14 0.05 UVA-WTFS- <0.26 0.56 NO.7-W21.2 0981S0021 0.00" +/- 0.04 0.27 +/- 0.05 -0.06 +/- 0.07 -0.09 +/-0.15 0.02 UVA-WTFS- <0.19 0.46 1 1 11 1 1NO.7-W6.2
'Calculated using the sum-of-fractions (SOF) to compare to the unity rule for the ESSAP data, as discussed in Section 4.3.3 of MARSSIM (NRC 2000). Refer to Appendix C for surface soil screening DCGLs. To account for hard to detect radionuclides, UVA applied a modified DCGL of 3.4 pCi/g Co-60.
bUVA data from Table 4-2 of the Final Status Survey Report, Revision 1 (UVA 2004a).
00
'Uncertainties are total propagated uncertainties at the 95% confidence level.
dZero value is due to rounding.
0o 6
,o
REFERENCES Oak Ridge Institute for Science and Education (ORISE). Document Review-Master Final Status Survey Plan and Addendums 001-008, University of Virginia, Charlottesville, Virginia
[Docket No. 50-62; Task No. 2.1]. Oak Ridge, TN; October 24, 2003.
Oak Ridge Institute for Science and Education. Document Review-Final Status Survey Documentation, University of Virginia, Charlottesville, Virginia [Docket No. 50-62; Task No.
2.2]. Oak Ridge, TN; July 12, 2004a.
Oak Ridge Institute for Science and Education. Survey Procedures Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; September 2, 2004b.
Oak Ridge Institute for Science and Education. Quality Assurance Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; August 31, 2004c.
Oak Ridge Institute for Science and Education. Laboratory Procedures Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; August 31, 2004d.
Oak Ridge Institute for Science and Education. Final Confirmatory Survey Plan for the University of Virginia Research Reactor, University of Virginia, Charlottesville, Virginia
[Docket No. 50-62; Task No. 2.8]. Oak Ridge, TN; February 28, 2005a.
Oak Ridge Institute for Science and Education. Review of UVA Responses to NRC RAIs. Oak Ridge, TN; January 20, 2005b.
U.S. Nuclear Regulatory Commission (NRC). Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM). Washington, DC: NUREG-1575, Revision 1; August 2000.
U.S. Nuclear Regulatory Commission. Consolidated NMSS Decommissioning Guidance:
Decommissioning Process for Materials Licensees. Washington, DC: NUREG-1757, Volume 1, Revision 1; September 2003.
University of Virginia (UVA). University of Virginia Decommissioning Plan. Charlottesville, VA; February 2000.
University of Virginia. Final Status Survey Report, Revision 1. Charlottesville, VA; November 2004a.
University of Virginia. Master Final Status Survey Plan, UVA-FS-002. Charlottesville, VA; Revision 1, April 2004b.
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APPENDIX A MAJOR INSTRUMENTATION University of Virginia Reactor projects\0981\Reports\2005-08-08 Revised Final Report.doc
APPENDIX A MAJOR INSTRUMENTATION The display of a specific product is not to be construed as an endorsement of the product or its manufacturer by the author or employer.
SCANNING INSTRUMENT/DETECTOR COMBINATIONS Alpha-Beta Ludlum. Floor Monitor Model 239-1 combined with Ludlum Ratemeter-Scaler Model 2221 coupled to Ludlum Gas Proportional Detector Model 43-37, Physical Area: 550 cm 2 (Ludlum Measurements, Inc., Sweetwater, TX)
Ludlum Ratemeter-Scaler Model 2221 coupled to Ludlum Gas Proportional Detector Model 43-68, Physical Area: 126 cm 2 (Ludlum Measurements, Inc., Sweetwater, TX)
Gamma Eberline Pulse Ratemeter Model PRM-6 (Eberline, Santa Fe, NM) coupled to Victoreen Nal Scintillation Detector Model 489-55, Crystal: 3.2 cm x 3.8 cm (Victoreen, Cleveland, OH)
Ludlum Model 12 (Ludlum Measurements, Inc., Sweetwater, TX) coupled to Victoreen NaI Scintillation Detector Model 489-55, Crystal: 3.2 cm x 3.8 cm (Victoreen, Cleveland, OH)
DIRECT MEASUREMENT INSTRUMENT/DETECTOR COMBINATIONS Beta Ludlum Ratemeter-Scaler Model 2221 coupled to Ludlum Gas Proportional Detector Model 43-68, Physical Area: 126 cm 2 (Ludlum Measurements, Inc., Sweetwater, TX)
University of Virginia Reactor A-1 projects\0981lReports\2005-08-08 Revised Final Report.doc
LABORATORY ANALYTICAL INSTRUMENTATION Low Background Gas Proportional Counter Model LB-5100-W (Oxford, Oak Ridge, TN)
High Purity Extended Range Intrinsic Detector CANBERRA/Tennelec Model No: ERVDS30-25195 (Canberra, Meriden, CT)
Used in conjunction with:
Lead Shield Model G-1 1 (Nuclear Lead, Oak Ridge, TN) and Multichannel Analyzer DEC ALPHA Workstation (Canberra, Meriden, CT)
High Purity Extended Range Intrinsic Detector Model No. GMX-45200-5 (AMETEK/ORTEC, Oak Ridge, TN) used in conjunction with:
Lead Shield Model SPG-16-K8 (Nuclear Data)
Multichannel Analyzer DEC ALPHA Workstation (Canberra, Meriden, CT)
High-Purity Germanium Detector Model GMX-30-P4, 30% Eff.
(AMETEK/ORTEC, Oak Ridge, TN)
Used in conjunction with:
Lead Shield Model G-16 (Gamma Products, Palos Hills, IL) and Multichannel Analyzer DEC ALPHA Workstation (Canberra, Meriden, CT)
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APPENDIX B SURVEY AND ANALYTICAL PROCEDURES No go go do do do so 0o No University of Virginia Reactor projects\O981\Reports\2005-08-08 Revised Final Report.doc
APPENDIX B SURVEY AND ANALYTICAL PROCEDURES PROJECT HEALTH AND SAFETY The proposed survey and sampling procedures were evaluated to ensure that any hazards inherent to the procedures themselves were addressed in current job hazard analyses (JHAs). All survey and laboratory activities were conducted in accordance with ORISE health and safety and radiation protection procedures.
A walkdown of the survey areas was performed in order to evaluate and identify potential health and safety issues. UVA provided general site-specific safety awareness-falls into the floor openings were of the greatest concern. Survey work was performed per the ORISE generic health and safety plans, a site-specific integrated safety management (ISM) pre-job hazard checklist, and the safety procedures discussed during the training.
QUALITY ASSURANCE Analytical and field survey activities were conducted in accordance with procedures from the following documents of the Environmental Survey and Site Assessment Program:
" Survey Procedures Manual, (September 2004)
" Laboratory Procedures Manual, (August 2004)
" Quality Assurance Manual, (August 2004)
The procedures contained in these manuals were developed to meet the requirements of Department of Energy (DOE) Order 414.1B and the U.S. Nuclear Regulatory Commission QualityAssurance Manualfor the Office of NuclearMaterialSafety and Safeguardsand contain measures to assess processes during their performance.
Quality control procedures include:
" Daily instrument background and check-source measurements to confirm that equipment operation is within acceptable statistical fluctuations.
" Participation in MAPEP, NRIP, and ITP Laboratory Quality Assurance Programs.
University of Virginia Reactor B-1 projects\0981\Reports\2005-08-08 Revised Final Reportdoc
- Training and certification of all individuals performing procedures.
- Periodic internal and external audits.
CALIBRATION Calibration of all field and laboratory instrumentation was based on standards/sources, traceable to NIST, when such standards/sources were available. In cases where they were not available, standards of an industry-recognized organization were used.
Detectors used for assessing surface activity were calibrated in accordance with ISO-7503 1 recommendations. The total efficiency (-total) was determined for each instrument/detector combination and consisted of the product of the 2n instrument efficiency (Ei) and surface efficiency (Fs): etota =- Ei x F,.
UVA selected Tc-99 as the calibration source (maximum beta energy of 292 keV) as it provides a conservative representation of the radionuclide mixture for all areas except Rooms M005 and M008 where Ni-63 was the chosen calibration source. ISO-7503 recommends an Es of 0.25 for beta emitters with a maximum energy of less than 0.4 MeV (400 keV) and an F of 0.5 for maximum beta energies greater than 0.4 MeV. UVA selected an F, of 0.25 in order to calculate a conservative cttal. UVA calibrated their hand-held gas-proportional instrumentation using a 2
0.8 mg/cm2 Mylar window for all areas except laboratories M005 and M008 where a 0.4 mg/cm window was used. ESSAP calibrated instruments for the confirmatory survey using the same methodology and detector window configuration as UVA.
Surface Scans Hand-held detectors were placed on contact with the calibration sources. A postulated hot-spot size of 100 cm 2 was assumed a priorifor determining scanning instrument efficiencies. The scanning Fi values were 0.47 and 0.18 for Tc-99 and Ni-63, respectively, for the hand-held gas proportional detectors; the calculated scanning E-,o values were 0.12 and 0.05 for Tc-99 and Ni-lInternational Standard. ISO 7503-1, Evaluation of Surface Contamination - Part 1: Beta-emitters (maximum beta energy greater than 0.15 MeV) and alpha-emitters. August 1, 1988.
University of Virginia Reactor B-2 projects\981\Reports\2005-08-08 Revised Final Reportdoc
63, respectively. Calibration source emission rates were not corrected for geometry when sources larger than the detectors were used.
The scanning Fto was determined for the floor monitor in the same fashion as above for the hand-held gas proportional detectors except typical efficiencies for the floor monitor were used rather than specific calibrations for this survey. The scanning Ei for Tc-99 was 0.24; the scanning stotw was 0.06.
Surface Activity Measurements The calibration F,values for the hand-held gas proportional detectors used for the confirmatory survey were 0.39 and 0.18 for Tc-99 and Ni-63, respectively. Calibration source emission rates were corrected to the active area of the detector when the calibration source area exceeded the detector area. The static etow values used were 0.10 and 0.05 for Tc-99 and Ni-63, respectively.
SURVEY PROCEDURES Surface Scans Surface scans were performed by passing the detectors slowly over the surface; the distance between the detector and the surface was maintained at a minimum - nominally about 1 cm. A large surface area, gas proportional floor monitor with a 0.8 mg/cm 2 window and a NaI scintillation detector was used to scan the floors of the surveyed areas. Wall surfaces were scanned using small area (126 cm 2) hand-held detectors with a 0.8 mg/cm2 window. For Rooms M005 and M008, hand-held detectors with 0.4 mg/cm2 windows were used to scan the floors, walls, and ceilings. Identification of elevated levels was based on increases in the audible signal from the recording and/or indicating instrument.
Scan minimum detectable concentrations (MDCs) were estimated using the calculational approach described in NUREG-15072 . The scan MDC is a function of many variables, including the background level. Site beta background levels were within the typical range of 800 to 1,400 cpm for the large area gas proportional detectors (floor monitors) and 250 to 450 cpm for the 2NUREG- 1507. Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions. US Nuclear Regulatory Commission. Washington, DC; June 1998.
University of Virginia Reactor B-3 projects\0981lReports\2005-08-08 Revised Final Report.doc
hand-held gas proportional detectors. Additional parameters selected for the calculation of scan MDC included a one-second observation interval, a specified level of performance at the first scanning stage of 95% true positive rate and 25% false positive rate, which yields a d' value of 2.32 (NUREG-1507, Table 6.1), and a surveyor efficiency of 0.5. To illustrate an example for the hand-held gas proportional detectors with 0.8 mg/cm 2 windows, the minimum detectable count rate (MDCR) and scan MDC can be calculated as follows:
bi = (250 cpm) (1 s) (1 min/60 s) = 4.2 counts MDCR = (2.32) (4.2 counts)1/2 [(60 s/min) / (1 s)] = 285 cpm MDCRsu-veyor = 285 1(0.5) Y = 403 cpm The scan MDC is calculated using the total scanning efficiency (ctotai) of 0.12:
2 Scan MDC = MDCRsunveyor dpm/100 cm etota The scan MDC was calculated to be 3,400 dpm/100 cm 2 . For the given background ranges, the following table summarizes the calculated scan MDC values.
Detector Scan MDC Range (dprn/100 cmr) 0.8 m*m/cm 2 Window 0.4 mg/cm 2 Window Hand-Held Gas Proportional 3,300 to 4,500 8,000 to 11,000 Floor Monitor 12,000 to 16,000 N/Aa a Not applicable The scan MDCs for the NaI scintillation detector for the contaminants of concern in surface soil were obtained directly from NUREG-1507 when available. The scan MDCs provided in NUREG-1507 were 5.8 and 10.4 pCi/g, respectively, for Co-60 and Cs-137. For Eu-152 in soil, the scan MDC was approximately 5.8 pCi/g 3 . The scan MDCs for other major gamma-emitting contaminants of concern were not provided in NUREG-1507. In such a case, it is standard procedure for ESSAP staff to pause and investigate any locations where gamma radiation is distinguishable from background levels.
3The scan MDC for Eu-152 was estimated based on empirical calculations for Nal response versus gamma energy provided in Decommissioning Health Physics: A Handbookfor MARSSIM Users, E.W. Abelquist; 2001.
University of Virginia Reactor B-4 projects\0981\Reports\2005-08-08 Revised Final Reportdoc
Surface Activity Measurements Surface activity measurements were performed on poured concrete, cinderblocks, tile, wall board, and corrugated metal. To account for the ambient gamma background, unshielded and shielded measurements were performed at each location. A 3/8-inch Plexiglas shield was used to determine the gamma count rate associated with the unshielded count rates. This thickness was demonstrated to block the beta particles from Sr-90, including the beta particles from the progeny Y-90. Since Y-90 emits beta particles higher in energy than Cs-137, the Plexiglas shield completely shielded measurement of the Cs-137 beta emissions. Surface activity was calculated by determining the net count rate, subtracting the shielded measurement from the unshielded measurement, then correcting for total efficiency and detector area size.
The static beta MDCs--calculated using the calibration check-out count rate-for the gas proportional detectors used for direct measurements are shown in the table below. The physical surface area assessed by the gas proportional detector used was 126 cm 2 .
Detector Window Calibration Check-Out Static MDC (mg/cm 2 ) Count Rate (cpm) (dpm/100 cm 2 )
0.4 392 1,500 0.8 380 740 Removable Activity Measurements Removable gross alpha and gross beta activity levels were determined using numbered filter paper disks, 47 mm in diameter. Moderate pressure was applied to the smear and approximately 100 cm 2 of the surface was wiped. Smears were placed in labeled envelopes with the location and other pertinent information recorded.
RADIOLOGICAL ANALYSIS Gross Alpha/Beta Smears were counted for two minutes on a low-background gas proportional system for gross 2 2 alpha and beta activity. The MDCs of the procedure were 9 dpm/100 cm and 15 dpm/100 cm for gross alpha and gross beta, respectively.
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Gamma Spectroscopy Samples of soil were dried, mixed, crushed, and/or homogenized as necessary, and a portion sealed in a 0.5-liter Marinelli beaker or other appropriate container. The quantity placed in the beaker was chosen to reproduce the calibrated counting geometry. Net material weights were determined and the samples counted using intrinsic germanium detectors coupled to a pulse height analyzer system. Background and Compton stripping, peak search, peak identification, and concentration calculations were performed using the computer capabilities inherent in the analyzer system. All total absorption peaks (TAP) associated with the radionuclides of concern were reviewed for consistency of activity. Total absorption peaks used for determining the activities of radionuclides of concern and the typical associated MDCs for a one-hour count time were:
Radionuclide TAP (MeV) MDC (pCi/g)
Co-60 1.173 0.05 Cs-137 0.662 0.05 Eu-152 0.344 0.11 Eu-154 0.723 0.13 Spectra were also reviewed for other identifiable TAPs.
DETECTION LIMITS Detection limits, referred to as minimum detectable concentration (MDC), were based on 3 plus 4.65 times the standard deviation of the background count [3 + (4.65$tBKG)]. Because of variations in background levels, measurement efficiencies, and contributions from other radionuclides in samples, the detection limits differ from sample to sample and instrument to instrument.
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40 40 APPENDIX C 40
SUMMARY
OF SURFACE SOIL SCREENING VALUES 10 10 University of Virginia Reactor projects\0981\Reports\2005-08-08 Revised Final Report.doc
APPENDIX C
SUMMARY
OF SURFACE SOIL SCREENING VALUES The following table lists the contaminants of concern and their associated surface soil screening values published in NUREG-1757, Volume 11.
Radionucide Guideline Value (pCi/g)
H-3 110 Fe-55 10,000 Pu-239/240 2.3 U-233/234 13.0 U-238 14.0 Ni-59 5,500 Cs-134 5.7 Cs-137 11.0 Co-60 3.8 Eu-152 8.7 Eu-154 8.0 Mn-54 15.0 Ag-110m 3.9 Zn-65 6.2 Sr-90 1.7 C-14 12.0 Ni-63 2,100 Tc-99 19.0
'U.S. Nuclear Regulatory Commission. Consolidated NMSS Decommissioning Guidance: Decommissioning Process for Materials Licensees. Washington, DC: NUREG-1757, Volume 1, Revision 1; September 2003.
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