ML052140239
| ML052140239 | |
| Person / Time | |
|---|---|
| Site: | Saxton File:GPU Nuclear icon.png |
| Issue date: | 07/27/2005 |
| From: | GPU Nuclear |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| E910-05-052 | |
| Download: ML052140239 (17) | |
Text
Final Status Survey Report For Saxton Nuclear Experimental Corporation Open Land Area Survey Unit OLI-6 Temporary Water Supply Trench In SNEC CV Yard Area Prepared by GPU Nuclear, Inc.
July 2005
Final Status Survey Report - Open Land Area Survey Unit OL1-6 Table of Contents Section No.
Page Executive Summary............................I
1.0 Purpose and Scope
~
3 2.0 Survey Area Description.......................................................
.3 3.0 Operating History...............................................
,.3 3.1 OLI-6 Area Use 3
3.2 OLI-6 Remediation Status 4
3.3 SNEC Facility Operating History...................................................................
4 4.0 Site Release Criteria 5
4.1 OLI-6 Area Specific DCGLw Values 5
5.0 Final Status Survey DesignIDQO Process.6 5.1 Description of Survey Unit "7
5.2 Survey Design for the OLl-6 Trench 8
6.0 Final Status Survey Results 8
6.1 Summary of Survey Results for OLl-6 Trench 8
6.2 OLI-6 Random Start Triangular Grid Systematically Spaced Soil Samples.9 7.0 Data Assessment.1.
7.1 Assessment Criteria 10 7.2 Survey Variations (Design, Survey Request, LTP).................................
1 1 7.2.1 Less Than 1 Meter Sample Depths.I I
7.3 Quality Control Measurements.
1.
7.4 Assessment Summary.....................................................................................
1,1 8.0 Final Status Survey Conclusions 1,1 9.0 References 13 10.0 Appendices 10.1 Appendix A SNEC Calculation No. E900-04-027, "CV Yard Survey Design -
Temporary Water Supply Trench in CV Yard", February 25, 2005.
10.2 Appendix A Survey Request Results Summary for SR-0189 (OL1-6) i
Final Status Survey Report - Open Land Area Survey Unit OLI -6 List of Figures Figure No.
Title Page I
Temporary Water Supply Trench in SNEC CV Yard Area Cover 2
A Section of the SNEC Facility Site Grid Map Showing Location Of OL1-6 1
ii
Final Status Survey Report - Open Land Area Survey Unit OLI-6 List of Tables Table No.
Title Page I
Volumetric Cs-137 DCGLw Value 6
2 DQO/Design Parameters/Results 7
3 OL1-6 Trench Sample Results 9
4 OL1-6 Alarm Point Sample Results 9
iii
Final Status Survey Report - Open Land Area Survey Unit OLI-6 Executive Summary This report presents the results and conclusions of the Final Status Survey (FSS) conducted by GPU Nuclear, Inc. within the SNEC facility OL1-6 open land area. This report provides summary results from volumetric scanning and sampling of soils within the aforementioned area. This survey work was performed in January of 2005. All survey work was performed in accordance with the SNEC License Termination Plan (LTP) (Reference 9.1).
OL1-6 Trench in CV Yard
/AW-/
AT 12 Appm imate Location of Trench ASAS-IZ l
AS I
I 17126 125 124 Figure 2, A sedion of the SNEC site grid map showing the location of OL1-6.
Survey data was collected from the OL1-6 survey unit according to data collection requirements specified in the survey design (Reference 9.2 and Appendix A-1).
During FSS activities, the following types of measurements were performed on materials found in these areas.
1
Final Status Survey Report-Open Land Area Survey Unit OLI-6
- 1. Nal detector scanning measurements were performed in approximately 163 m2 of the OL1-6 area. The OL1-6 site area is considered a Class 1-survey unit. The scan coverage requirement for this area (100%) is given in Reference 9.1, Table 5-5.
- 2. Not counting quality control and replicate sampling, a total of twenty (21) soil/soil-like samples were obtained from the OL1-6 survey unit (one sample was taken at a biased location). Sample locations were selected using the random start, triangular grid systematic spacing methodology. In addition, two (2) samples were collected in areas that indicated slightly elevated count rates during the scan process. Every sample was analyzed by gamma-ray spectroscopy to determine the presence of radionuclides that resulted from SNEC facility operations. Two (2) quality control samples were taken in the survey unit. Cs-137 is used as the surrogate radionuclide of interest.
FSS scan survey results were less than the action level for most of the applicable areas described in this report. Two (2) small areas exceeded the assigned alarm point of 2 300 gross counts per minute (gcpm), using a 2" by 2" sodium iodide detector. When sampled, no analysis result from samples collected in either of the two alarm point locations exceeded the DCGLw.
All soil and soil-like material samples taken at every location were below the applicable DCGLw.
Therefore, this collection of FSS data demonstrate that this survey unit meets the radiological criteria for unrestricted use specified in 10 CFR 20.1402 (Reference 9.3).
Based on the results of this final status survey effort, GPU Nuclear, Inc. concludes that the OL1-6 open land area meets the NRC requirements for release to unrestricted use.
2
Final Status Survey Report - Open Land Area Survey Unit 011-6
1.0 Purpose and Scope
This report presents the results and conclusions of the final status survey performed on the following areas:
0 Open Land Survey Unit OLl Class I area This survey effort provides the information required by 10 CFR 50.82(a)( 1) (Reference 9.4) and SNEC's License Termination Plan (LTP), and demonstrate that this area meets the radiological criteria for unrestricted use specified in 10 CFR 20.1402.
2.0 Survey Area Description The Temporary Water Supply Trench in the OLI area was installed in1986 to supply water from an outside well to a trailer complex. Clean materials were used to lay the water line (PVC pipe, etc.), but slightly contaminated soil was used to backfill the trench. These materials were removed, and the open trench area was then surveyed IAW FSS methodology so that clean materials could be used to backfill the trench.
The open land areas of OL1-6 resides in the larger OL1 Containment Vessel (CV) Yard area, east southeast of the former SNEC Containment Vessel location. The exposed surface area of this survey unit is about 163 square meters and it is a Class 1-survey unit.
OL1-6 is contained in the area enclosed by site grid markers AS-127 and AW-127 on the west, and on the east by grid markers AS-125, and AW-125 (Reference 9.5).
Soils from this area contains a significant quantity of Saxton Steam Generating Station (SSGS) fly ash and coal dirt. In addition, some of the soil was added as part of an earlier soil remediation effort. Remediation was required in the 011-6 Trench area and pre-cleanup concentrations of Cs-137 ranged to more than forty (40) pCi/g. Subsequent cleanup operations have reduced the Cs-137 concentrations in this area to below the applicable DCGLw.
3.0 Operating History 3.1 OL1-6 Area Use The OL1-6 area has been used for set-up operations for many decommissioning activities, and is part of the SNEC Facility 1.1 acre site. The former Control and Auxiliary building, Radioactive Waste Disposal Facility and connecting tunnel complex were all in the general 3
Final Status Survey Report - Open Land Area Survey Unit OLI-6 vicinity of the OL1-6 area. In addition, the radioactive waste storage bunker was also near this area.
3.2 OLI-6 Remediation Status A review of pre-remediation survey data pertaining to this area was conducted in support of this survey design. Analysis of soil samples showed Cs-137 concentrations ranging from -0.1 pCilg to -43 pCilg (see Appendix A-1, Attachment 7-1). Remediation activities were used to lower the mean concentration of Cs-137 in this area to a concentration less than the applicable DCGLw.
3.3 SNEC Facility Operating History The Saxton Nuclear Experimental Corporation (SNEC) facility featured a pressurized water reactor (PWR), which was licensed to operate at 23.5 megawatts thermal (23.5 MWth). The facility is owned by the Saxton Nuclear Experimental Corporation and is licensed by GPU Nuclear, Inc. The SNEC facility is maintained under a Title 10 Part 50 license and associated Technical Specifications. In 1972, the license was amended to possess but not operate the SNEC reactor.
The facility was build from 1960 to 1962 and operated from 1962 to 1972, primarily as a research and training reactor. After shutdown in 1972, the facility was placed in a condition equivalent to the current SAFSTOR status. Since then, it has been maintained in a monitored storage condition. The fuel was removed in 1972 and shipped to a (now DOE) facility at Savannah River, South Carolina, who is now the owner of the fuel. As a result of this, neither SNEC nor GPU Nuclear, Inc. has any further responsibility for the spent fuel from the SNEC facility.
The reactor, containment vessel and support buildings have all been removed from the site. The building and structures that supported reactor operation were partially decontaminated by 1974. In the late 1980's and through the 1990's, additional decontamination, disassembly and removal of the containment vessel support buildings, large and small components and other miscellaneous support equipment was complete.
By 1992 decontamination and dismantlement of the reactor support structures was complete. Large components such as the pressurizer, steam generator, and reactor vessel were removed in late 1998. The removal of the steel Containment Vessel (CV) (to - 4' below grade), and backfill was complete by late 2003. More recently, decontamination, 4
Final Status Survey Report-Open Land Area Survey Unit OL1-6 disassembly and demolition of the remaining SNEC facility buildings including remnants of the coal fired Saxton Steam Generating Station (SSGS) has taken place. The SNEC facility is currently in the process of performing the Final Status Survey for unrestricted release leading to license termination.
4.0 Site Release Criteria The site release criteria as applied to the OL1-6 Trench area correspond to the radiological dose criteria for unrestricted use per 10 CFR 20.1402. The dose criteria is met "if the residual radioactivity that is distinguishable from background radiation results in a Total Effective Dose Equivalent (TEDE) to an average member of the critical group that does not exceed 25 mrem/yr, including that from groundwater sources of drinking water; and that the residual radioactivity has been reduced to levels that are as low as reasonably achievable (ALARA).'
Levels of residual radioactivity that correspond to the allowable dose and meet site or survey unit release criteria were derived by analyses using either the building occupancy (surface area) or resident farmer (volumetric) scenarios. The dose modeling for these scenarios is explained in Chapter 6 of the SNEC LTP, Revision 3. The derived concentration guideline levels (DCGLs) determined in the LTP form the basis for satisfying the site release criteria.
As described in Chapter 6 of the SNEC LTP (Reference 9.1), a correction to the gross activity DCGLw is made to address de-listed radionuclides and provide a reasonable SNEC established safety factor. The SNEC facility has instituted an administrative limit of 75% for the allowable dose (DCGL) for all measurement results. Thus the de-listed radionuclide dose is accounted for by using the 75% administrative limit.
4.1 OL1-6 Area Specific DCGLw Values The sample database used to determine the effective radionuclide mix for the CV Yard OL1-6 Trench area has been drawn from previous samples that were assayed at off-site laboratories. This list is shown in Appendix A-1, Attachment 2-1 to 2-7, and includes (23) analysis results. Review of the data shows several radionuclides have not been positively identified at any significant concentration. These radionuclides have been removed from the data set and were not be considered further. Radionuclides removed include Am-241, C-14, Eu-152, Ni-63, Pu-238, Pu-239 and Pu-41. Additionally, the data shows Cs-137 to 5
Final Status Survey Report-Open Land Area Survey Unit OLI-6 be the predominant radioactive contaminant found in the area. Sr-90 on the other hand, was positively identified in only one (1) sample. H-3 was identified as a positive contaminant in six (6) samples, and Co-60 was identified in three (3) samples. These results were decayed and pooled to provide the Cs-137 surrogate value shown in Table 1.
Table 1, Volumetric Cs-137 DCGLw Value I Volumetric DCGLw (pCIg - Cs--37) 1 l
5.75 (4.31 A.L.)
l NOTE: A.L is the Administrative Umit (75% of effective DCGLw) 5.0 Final Status Survey Design/DQO Process Survey Designs (SD's) (e.g., Appendix A-1) are developed IAW applicable sections of the SNEC License Termination Plan (LTP) and site procedures (Reference 9.7). During development, characterization activities are reviewed along with any post-remediation survey or sampling activities (as applicable). Survey unit variability is established from the best available or most representative measurement and/or sampling result. The Compass computer program (Reference 9.8) is then used to develop MDCscan parameters (for structural surfaces), the number of survey or sampling points in each survey unit, and other DQO design parameters. For open land areas, methodology from NUREG-1507 (Reference 9.9) is used to calculate MDCscan values that are then input to the Compass computer program. For structural surfaces, representative background values are extracted from previous measurements of non-impacted like-materials of similar age whenever possible. For open land areas, background concentrations of relevant SNEC radionuclides are not subtracted from sample data sets prior to developing individual survey unit surrogate levels (of Cs-137). Thus the effective DCGLw values for open land areas are conservatively biased.
For most survey units, the number of Compass calculated sample and/or survey locations are augmented to provide "more than the minimum required coverage". Sample and/or survey point locations are plotted on drawings of individual survey areas using the Visual Sample Plan (VSP) computer code (Reference 9.10). Diagrams showing sample and/or survey point locations are clearly depicted on survey maps along with any necessary physical dimensions from known site area landmarks. Diagrams are then provided to individual survey teams through the use of the Survey Request (SR's) procedure process (Reference 9.11). SR's are issued as field working guidance documents. Before 6
Final Status Survey Report - Open Land Area Survey Unit OLI-6 implementation, all SD's and SR's are reviewed and approved by the SNEC RSO (or his representative). Data Quality Objectives (DQO's) for the OL1-6 area is presented in the following table.
Table 2, DQO/Design Parameters/Results Sur"I"ey Unift
~
Survey Design Calculation. No.
E900-04027 SNEC Survey Request No.
SR-0189 Survey Area Classification Class 1 Total Estimated Area in Survey Unit (m2) 163 Material Type SoiVSoil-Like Materials Scanning Goal (m2) 163 (100%)
Actual Area Scanned (M
- 2) 163 (100%)
Applicable Statistical Test Sign Type I Decision Error (a) 0.05 Type II Decision Error (0) 0.1 Volumetric DCGLw (pCi/g Cs-137)-
5.75 (4.31 A.L)
LBGR (pCig Cs-137) 3.8 Estimated q (pCig Cs-1 37) 0.39 Ala (Planning Value) 1.31 Actual q From Survey Un.it(pCg) 1.01 Samples Required by Compass 16 Samples Specified by VSP^
20 Estimated Scan MDC (pCig Cs-137) 3.3 Scan Speed (cm/sec) 25 Survey Instrument Types L-2350-1, w/44-10 2-by 2-Nal with Cs-1 37 Window Setting Instrument counts/disintegration (cpmlmR/h) 2 205,000 Scanning Alarm Point (gcpm)
> 300 Detector Gap to Surface (inches) 4
- ,'AL Is the SNEC Facility Administrative L it (75% of the apprcabe DCGLw) a' VSP Is Visual Sample Plan. VSP is Used to p tonia Ta ly severa additional points are added during this process to compensate for potential losses In thefield.'
This Instrument uses a narrow wmdow detector Setting thatkn e snal to noise ratio for Cs-i37 5.1 Description of Survey Unit Figure 2 shows the OL1-6 Trench and its approximate location on a section of the SNEC site grid diagram. The trench area is about one (1) meter deep and 36 meters long north to south. At its widest point the trench is about two (2) meters wide. The sides are included in the estimate of the area.
7
Final Status Survey Report - Open Land Area Survey Unit OLI-6 5.2 Survey Design for the OLI-6 Trench The survey design for OL1-6 area is provided as Appendix A-1. Since the OL1-6 area is a Class 1 open land area, the initial scanning goal was set at 100% of the total area available. This assignment is in accordance with Reference 9.1, Table 5-5.
The number of random start, triangular grid, systematically spaced sample points were determined using the Compass computer program (Reference 9.7). The minimum number of sample points selected by Compass for this survey unit was sixteen (16). The sampling depth was not specified since the depth of the trench was already about one (1) meter deep, which matches the site area dose model discussed in Chapter 6 of the SNEC LTP (Reference 9.1). All sample points were placed on survey maps of the OL1-6 area using the Visual Sample Plan (VSP) computer code (Reference 9.10). These locations can be seen in Appendix A-1, Attachment 6-1.
6.0 Final Status Survey Results 6.1 Summary of Survey Results for OLI-6 Trench FSS scanning requirements for a Class I open land area are 100% of the available surface area (Reference 9.1, Table 5-5). 100% of the survey unit was scanned during FSS activities (see Appendix A-2). Therefore, scan coverage requirements as listed in the survey design for this area have been met.
Two (2) instrument alarm points (AP) were encountered, one in grid AS-127 and one in the adjacent grid AT-127. AP1 was located about four (4) meters from the south end of the trench, and AP2 was located about 8.5 meters from the south end of the trench. These alarm points were sampled to verify the Cs-137 concentration. All sample results are provided in Table 3 and 4, and shown that the applicable DCGLw has not been exceeded in any case. Since the DCGLw was not exceeded, no further actions are necessary to show compliance with SNEC LTP requirements. Note that the variability of FSS samples identified in Table 3 are below the initial variability estimate used in the survey-planning phase (see Table 2 initial sigma value).
8
Final Status Survey Report-Open Land Area Survey Unit OLI-6 6.2 OLI-6 Random Start, Triangular Grid, Systematically Spaced Soil Samples Table 3, OLI-6 Trench Sample Results I
SNEC Sample ID Sampling Location Cs.137 (pCVg)
SXSL9247 SP-A 0.28 SXSL9248 SP-2 0.18 SXSL9249 SP-3 0.09 SXSL9250 SP-4
<0.1 SXSL9251 SP-5
<0.1 SXSL9253 SP-6
<0.1 SXSL9254 SP-7
<0.08 SXSL9255 SP-8 0.4 SXSL9256 SP-9 0.14 SXSL9257 SP-10 4.1 SXSL9258 SP-11 1.6 SXSL9259 SP-12 0.83 SXSL9260 SP-13
<0.1 SXSL9261 SP-14
<0.1 SXSL9262 SP-15
< 0.09 SXSL9264 SP-16 0.16 SXSL9265 SP-17
<0.14 SXSL9266 SP-18
<0.14 SXSL9267 SP-19 2.67 SXSL9268 SP-20 0.37 Averagel 0.55 Sigma =I 1.01 Maximum-*I 4.10 As stated previously, two alarm points (AP) were reached in the OL1-6 survey unit (see Table 4). The alarm was reported as 312 to 362 gcpm, which is above the AP of > 300 gcpm. The AP was investigated by sampling the elevated area. These sample results are provided in Table 4.
Table 4, OL1-6 Alarm Point Sample Results SNEC Sample ID Sampling Location Cs-137 (pClIg)
SXSL9310 Trench Sump Area I 0.4 1
SXSL9196 AP-1
< 0.12 SXSL9197 AP-2 0.18 Since all analysis results for Cs-137 were below the DCGLw, no additional samples were taken.
9
Final Status Survey Report-Open Land Area Survey Unit OL1-6 Sample results from the OL1-6 survey unit did not show levels of Cs-137 above the applicable DCGLw. More than half of the FSS sample results from this area were below the minimum detectable concentration for Cs-137, and the maximum concentration in this area is less than the DCGLw. As a result, this survey unit meets the release criteria.
7.0 Data Assessment 7.1 Assessment Criteria Final status survey data has been reviewed to verify authenticity, appropriate documentation, quality, and technical acceptability. The review criteria for data acceptability are:
- 1) The instruments used to collect the data were capable of detecting the radiation of the radionuclide of interest at or below the investigation levels.
- 2) The calibration of the instruments used to collect the data was current and radioactive sources used for calibration were traceable to recognized standards or calibration organizations.
- 3) Instrument response was checked before, and when required, after instrument use each day data was collected.
- 4) Survey team personnel were properly trained in the applicable survey techniques and training was documented.
- 5) MDC values and the assumptions used to develop them were appropriate for the instruments and the survey methods used to collect the data.
- 6) The survey methods used to collect the data were appropriate for the media and types of radiation being measured.
- 7) Special instrument methods used to collect data were applied as warranted by survey conditions, and were documented in accordance with an approved site Survey Request procedure.
- 8) The custody of samples that were sent for off-site analysis was tracked from the point of collection until final results were provided.
10
Final Status Survey Report - Open Land Area Survey Unit OLI -6
- 9) Final status survey data consists of qualified measurement results representative of current facility status and were collected in accordance with the applicable survey design package.
If a discrepancy existed where one or more criteria were not met, the discrepancy was reviewed and corrective action taken (as appropriate) in accordance with site procedures.
7.2 Survey Variations (Design, Survey Request, LTP) 7.2.1 Less Than 1 Meter Sample Depths In OL1-6, samples were taken at less than one (1) meter depths since the trench bottom was already about one (1) meter deep. Ultimately, this area was back filled and covered with clean materials as part of the SNEC site closeout process.
7.3 Quality Control Measurements Repeat scan measurements and samples were performed and met the applicable acceptance criteria established in Section 4.6 of SNEC Procedure E900-IMP-4520.04 (Reference 9.11). Quality Control (QC) measurements are reported in Appendix A-2. All QC measurements are taken in accordance with the requirements of Reference 9.1 and applicable site procedures, which requires that at least 5% of all samples and scans be re-done. No discrepancies are reported and at least 5% or more of all samples and scan measurements were repeated with acceptable results.
7.4 Assessment Summary Statistical testing of the data does not need to be performed for this final status survey since the data clearly show that the survey unit(s) meet the site release criteria. These survey units clearly meet the criterion because of the following:
- 1. Z All measurements in these survey units are less than or equal to the DCGLW, or
- 2. [1 A background reference area was used, and the difference between the maximum survey unit measurement and the lowest background reference area measurement are less than or equal to the DCGL.
8.0 Final Status Survey Conclusions The FSS for the OL1-6 open land area was performed in accordance with the SNEC LTP and site implementing procedures. Final status survey data were collected to meet and/or 11
Final Status Survey Report - Open Land Area Survey Unit OLI-6 exceed the quantity and quality specified for these areas as prescribed by the applicable survey design. The survey data for each survey unit met the following conditions:
- 1.
The average residual radioactivity within the OL1-6 area is less than the assigned DCGLw.
- 2.
Since all measurements were less than the DCGLw, no DCGLEMc criteria need be applied.
- 3.
No additional remediation was needed in these areas after FSS activities were complete to reduce levels of residual radioactivity below concentrations necessary to meet site DCGLw values.
These conditions satisfy the release criteria established in the SNEC LTP and the radiological criteria for unrestricted use given in 10 CFR 20.1402. Therefore, it is concluded that the SNEC OL1-6 Trench area as described in this report is suitable for unrestricted release.
12
Final Status Survey Report -Open Land Area Survey Unit OLI-6 9.0 References 9.1 SNEC License Termination Plan 9.2 SNEC Calculation E900-04-027, "CV Yard Survey Design -
Temporary Water Supply Trench in CV Yard", February 25, 2005.
9.3 Code of Federal Regulations, 10 CFR 20.1402.
9.4 Code of Federal Regulations, 10 CFR 50.82(a)(1 1).
9.5 SNEC Facility Site Area Grid Map - Drawing Number SNECRM-020.
9.6 SNEC Facility Historical Site Assessment Report, March 2000.
9.7 SNEC Procedure E900-IMP-4500.59, "Final Site Survey Planning and DQA" 9.8 COMPASS computer program, Version 1.0.0, Oak Ridge Institute for Science and Education.
9.9 NUREG-1507, "Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions'.
9.10 Visual Sample Plan computer program, Version 3.0, Battelle Memorial Institute.
9.11 SNEC Procedure E900-IMP-4520.04, "Survey Methodology to Support SNEC License Termination" 9.12 SNEC Procedure E900-ADM-4500.60 "Final Status Survey Report".
9.13 NUREG 1575 "Multi-Agency Radiation Survey and Site Investigation Manual" (MARSSIM), revision 1 August 2000 13