ML080290289
| ML080290289 | |
| Person / Time | |
|---|---|
| Site: | Plum Brook File:National Aeronautics and Space Administration icon.png |
| Issue date: | 01/30/2008 |
| From: | Glenn C NRC/FSME/DWMEP/DURLD |
| To: | Whitlow W US National Aeronautics & Space Admin (NASA), John H. Glenn Research Ctr at Lewis Field |
| Glenn C | |
| References | |
| Download: ML080290289 (5) | |
Text
January 30, 2008 Mr. Woodrow Whitlow Jr.
Center Director, National Aeronautics and Space Administration John H. Glenn Research Center at Lewis Field 21000 Brookpark Road MS-2 Cleveland, Ohio 44135
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING NASAS REVISED FINAL STATUS SURVEY PLAN FOR THE PLUM BROOK REACTOR FACILITY, SANDUSKY, OHIO
Dear Mr. Whitlow:
The U.S. Nuclear Regulatory Commission (NRC) has reviewed National Aeronautics and Space Administrations (NASAs) Final Status Survey (FSS) Plan for the Plum Brook Reactor Facility, (NASA, 2007) and has identified the enclosed request for additional information. Please direct your response to the bolded text as other information is provided for context.
NRC looks forward to NASAs response so we can complete our review of NASAs FSS Plan and associated amendment request.
Sincerely,
/RA/
Chad Glenn, Senior Project Manager Decommissioning and Uranium Recovery Licensing Directorate Division of Waste Management and Environmental Programs Office of Federal and State Materials and Environmental Management Programs Docket Nos.: 50-30 and 50-185
Enclosure:
Request for Additional Information cc: NASA Service List
January 30, 2008 Mr. Woodrow Whitlow Jr.
Center Director, National Aeronautics and Space Administration John H. Glenn Research Center at Lewis Field 21000 Brookpark Road MS-2 Cleveland, Ohio 44135
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING NASAS REVISED FINAL STATUS SURVEY PLAN FOR THE PLUM BROOK REACTOR FACILITY, SANDUSKY, OHIO
Dear Mr. Whitlow:
The U.S. Nuclear Regulatory Commission (NRC) has reviewed National Aeronautics and Space Administrations (NASAs) Final Status Survey (FSS) Plan for the Plum Brook Reactor Facility, (NASA, 2007) and has identified the enclosed request for additional information. Please direct your response to the bolded text as other information is provided for context.
NRC looks forward to NASAs response so we can complete our review of NASAs FSS Plan and associated amendment request.
Sincerely,
/RA/
Chad Glenn, Senior Project Manager Decommissioning and Uranium Recovery Licensing Directorate Division of Waste Management and Environmental Programs Office of Federal and State Materials and Environmental Management Programs Docket Nos.: 50-30 and 50-185
Enclosure:
Request for Additional Information cc: NASA Service List DISTRIBUTION:
ML080290289 Office DWMEP DWMEP DWMEP Name CGlenn TMixon RTadesse Date 01/28/08 01/30/08 01/30/08
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OFFICIAL RECORD COPY
National Aeronautics and Space Administration Service List cc:
Ohio Department of Health ATTN: Radiological Health Program Director P.O. Box 118 Columbus, Ohio 43216 Ohio Environmental Protection Agency Division of Planning Environmental Assessment Section P.O. Box 1049 Columbus, Ohio 43216 Mr. J. Eric Denison Bureau of Radiation Protection Ohio Department of Health P.O. Box 118 Columbus, Ohio 43216 Mr. Thomas W. Hartline, Director Safety and Mission Assurance Directorate National Aeronautics and Space Administration John H. Glenn Research Center at Lewis Field 21000 Brookpark Road MS 3-6 Cleveland, OH 44135 Mr. Keith M. Peecook, Decommissioning Program Manager National Aeronautics and Space Administration Plum Brook Reactor Project Office Plum Brook Station 6100 Columbus Avenue NASA Trailer #1 Sandusky, OH 44870
Enclosure REQUEST FOR ADDITIONAL INFORMATION REGARDING U.S. NUCLEAR REGULATORY COMMISSION REVIEW OF NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NASAS REVISED FINAL STATUS SURVEY PLAN
- 1.
FSSP Section 3.3, pg. 3-3 states The PBRF dose goal for EP [embedded piping] is 1 mrem/yr. However, at the discretion of PBRF, different dose goals could be applied in different areas as long as the residual contamination on the structure surface in the survey unit containing the given EP is sufficiently low to allow for the selected dose goal. For example, if the FSS results indicate that the residual contamination level in the Hot Dry Storage is 0.5 times the DCGL, the dose from the two drains in this survey unit could be as high as 12.5 mrem/yr.
If NASA cannot achieve the Plum Brook Reactor Facility (PBRF) dose goal of 1 mrem/year for embedded piping, will NASA reduce the building surface derived concentration guideline levels (DCGLs) to ensure that the overall dose criteria of 25 mrem/year is met?
- 2.
Appendix B, Section 5.1, pg. B-6 states The generic values used for the most dose-sensitive parameter (i.e., the distribution coefficient), are relatively high. This results in retaining radionuclides in soil rather than removing them by groundwater, which produces conservative dose estimates through the external exposure pathway for the radionuclides controlling dose at the PBRF.
- 1) Table B-5 provides the distribution coefficient (Kd) values used for soil and cites NUREG-1549 as the source of the values. Please support the statement that the generic Kd values from NUREG-1549 are relatively high. The support should include a comparison to Kd values from other literature sources based on the specific soil types and conditions at the site. For example, on page B-20 the Kd values for concrete are supported by three independent references.
- 2) While a high Kd value does retain the contaminant in the soil resulting in higher external exposure pathways, a low Kd value may increase the dose through groundwater pathways. Has this potential effect of lower Kd values been considered or examined?
- 3.
Appendix B, Table B-6, pg. B-9 states The parameter Shielding factor, external gamma has a value of 0.47.
Please explain how NASA determined the shielding factor of 0.47 and verify that the external gamma shielding factor has been properly defined and applied in the final status survey Plan (FSSP) RESRAD calculations.
Footnote (d) states that this value is based on the sum of the product of the means for the fraction of time and shielding dose factor for outdoor and indoor exposure. The Users Manual for RESRAD Version 6 (ANL 2001) states, on page A-7, that the shielding factor accounts for the reduction in the external exposure rate afforded by on-site
2 buildings or other structures while the individual is indoors (default value is 0.7). While the inclusion of the fraction of time spent outdoors, presumably with less shielding than indoors, results in a more conservative result, it is a deviation from the prescribed meaning of the RESRAD parameter.
- 4.
Appendix B, Section 6, pg. B-23 states The last step in the subsurface structure DC calculation is the conversion of the pCi/g volumetric DCGLV to an Effective Surface DCGL (DCGLES).
Please provide an explanation for the use of the porosity term (1-n).
The conversion details are provided following this statement. The DCGLES accounts for the potentiality that building debris will be used as backfill in the below-grade areas of the site. The DCGLES is used in lieu of the building reuse scenario surface DCGLs, which were developed with RESRAD-BUILD, when the DCGLES is the more conservative value.
Conceptually, the DCGLES appears valid and appropriate. However, please clarify why the porosity term (1-n) has been included in the calculation of the concrete debris mass.
The goal of the conversion is to correlate a surface activity to a volumetric activity.
DCGLV = Radionuclide Inventory/Concrete Debris Mass Radionuclide Inventory = (activity surficial concentration (activity per area)) (total surface area of the concrete)
Concrete Debris Mass = (concrete volume)(concrete density)(1-n)
Where n = porosity = 0.41, and density = 2.4 g/cm3 2.4 g/cm3 is a nominal value for concrete density, and presumably already includes a nominal porosity. Since density is defined as mass per volume, then mass should equal volume times density without consideration of the porosity included in that density.
One possible intent of the porosity term may be to consider the change in concrete porosity (and subsequently the change in density) during demolition. However, the surficial activity is measured while the building is intact (pre-demolition). The activity per mass of concrete is established pre-demolition using the relation above without inclusion of the porosity term. If the concrete is later demolished following surficial activity measurement, the porosity of the concrete may change thereby changing the concrete mass per volume, but the previously measured/calculated activity per mass should not change.
Since the assumed concrete porosity is approximately 40% (0.41), removal of the porosity term in the conversion equation would result in DCGLES values that are 40% lower than those currently in the Final Status Survey Plan.