ML061870512
| ML061870512 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear, FitzPatrick  |
| Issue date: | 07/19/2006 |
| From: | Terao D NRC/NRR/ADRO/DORL/LPLIV |
| To: | Buford F Entergy Operations |
| Vaidya B, NRR/DORL/LP4, 415-3308 | |
| References | |
| TAC MD1737, TAC MD1738 | |
| Download: ML061870512 (11) | |
Text
July 19, 2006 Mr. F. G. Burford Acting Director Nuclear Safety and Licensing Entergy Operations, Inc.
1340 Echelon Parkway Jackson, MS 39213-8298
SUBJECT:
ARKANSAS NUCLEAR ONE, UNIT 2, AND JAMES A. FITZPATRICK NUCLEAR POWER PLANT - APPLICATION TO USE EFFECTIVE DOSE EQUIVALENT WEIGHTING FACTORS FOR EXTERNAL EXPOSURE (TAC NOS. MD1737 AND MD1738)
Dear Mr. Burford:
By letter dated May 16, 2006, Entergy Operations, Inc. and Entergy Nuclear Operating, Inc.
(Entergy or the licensee) requested the U.S. Nuclear Regulatory Commission's (NRC's) approval for the use of the weighting factors provided in the American National Standard Institute (ANSI) HPS N13.41-1997 (the standard) for external radiation exposures when demonstrating compliance with total effective dose equivalent (TEDE), based on requirements in Part 20 of Title 10 to the Code of Federal Regulations (10 CFR) for Arkansas Nuclear One, Unit 2 (ANO-2), and James A. Fitzpatrick Nuclear Power Plant (JAF).
The NRC staff has completed its review. Enclosed is the NRC staffs related Safety Evaluation that concludes that your request for the use of the weighting factors provided in the standard for external radiation exposures when demonstrating compliance with TEDE, based on requirements in 10 CFR Part 20 for ANO-2 and JAF is acceptable.
F. G. Burford Please contact me at (301) 415-1302 or Bhalchandra K. Vaidya at (301) 415-3308, if you have any questions on this matter.
Sincerely,
/RA/
David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-368 and 50-333
Enclosure:
Safety Evaluation cc w/encl: See next page
F. G. Burford Please contact me at (301) 415-1302 or Bhalchandra K. Vaidya at (301) 415-3308, if you have any questions on this matter.
Sincerely,
/RA/
David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-368 and 50-333
Enclosure:
Safety Evaluation cc w/encl: See next page DISTRIBUTION:
PUBLIC RidsAcrsAcnwMailCenter RidsNrrDorlLpl1-1 (RLaufer)
LPLIV r/f LPLI-1 r/f RPedersen, DIRS RidsNrrDorlLpl4 (DTerao) RidsNrrLALFeizollahi RidsNrrLASLittle RidsNrrPMBVaidya RidsNrrPMDHolland RidsNrrPMJBoska RidsDorlDpr JLamb (RIV) BSosa (RI)
RidsRgn4MailCenter (DGraves) RidsOgcRp RidsRgn1MailCenter (ECobey) SBernal, DIRS ACCESSION NO: ML061870512 NRR-106 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/IHPB/BC OGC NRR/LPL4/BC NAME BVaidya LFeizollahi TFrey MLemoncelli DTerao DATE 07/13/06 07/13/06 06/23/06 07/17/06 07/19/06 OFFICIAL RECORD COPY
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE APPROVAL TO USE WEIGHTING FACTORS FOR EXTERNAL RADIATION EXPOSURES ENTERGY OPERATIONS, INC. AND ENTERGY NUCLEAR OPERATING, INC.
ARKANSAS NUCLEAR ONE, UNIT 2, AND JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NOS. 50-368 AND 50-333
1.0 INTRODUCTION
By letter dated May 16, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML061430359), Entergy Operations, Inc. and Entergy Nuclear Operating, Inc. (Entergy or the licensee) requested the U.S. Nuclear Regulatory Commission's (NRC's) approval for the use of the weighting factors provided in the American National Standard Institute (ANSI) HPS N13.41-1997 (the standard) for external radiation exposures when demonstrating compliance with total effective dose equivalent (TEDE), based on requirements in Part 20 to Title 10 of the Code of Federal Regulations (10 CFR) for Arkansas Nuclear One, Unit 2 (ANO-2), and James A. Fitzpatrick Nuclear Power Plant (JAF). The effect of granting this request would be to allow the licensee the option to control TEDE using the weighted external exposure measurements in those cases where it is a more accurate predictor of the risk from occupational radiation exposure.
2.0 REGULATORY EVALUATION
The radiation protection approach and dose limits contained in 10 CFR Part 20 are based on the recommendations of the International Commission on Radiation Protection (ICRP) in their 1977 Publication No. 26 (ICRP 26). For stochastic effects, the ICRPs recommended dose limitation is based on the principle that the risk should be equal, whether the whole body is irradiated uniformly or there is non-uniform irradiation (such as when radioactive materials are taken into the body and, depending on their physical and chemical properties, concentrate in certain tissues and organs). Therefore, the ICRP 26 recommendations are based on controlling the sum of the risk weighted doses to selected organs.
Effective dose equivalent (EDE or E) is defined in 10 CFR 20.1003 as the sum of the products of the dose equivalent to the organ or tissue (T) and the weighting factors (W T) applicable to each of the body organs or tissues that are irradiated (E = W TT ).
For the purposes of implementing workplace controls, and due to the difference in dosimetry, 10 CFR Part 20 breaks this EDE into two components: (1) dose resulting from radioactive sources internal to the body, and (2) dose resulting from sources external to the body. Dose limits and other requirements in Part 20 are based on the sum of these external and internal exposures. For radioactive material taken into the body, the occupational dose limit is based on the resulting dose equivalent integrated over 50 years, or committed effective dose equivalent (CEDE) defined in 10 CFR 20.1003 as W TT,50.
The TEDE is defined in 10 CFR 20.1003 as the sum of the deep-dose equivalent (DDE) (for external exposures) and the committed effective dose equivalent (for internal exposures).
TEDE = DDE + CEDE The organ weighting factors (W T) are the proportion of the risk of stochastic effects resulting from the dose to that organ or tissue to the total risk of stochastic effects when the whole body is irradiated uniformly. The weighting factors are applicable to the organs and tissues whether the dose results from radiation sources internal or external to the body. However, measuring the dose to the various organs and tissues with a dosimeter worn outside the body, presents some practical difficulties. If the body is irradiated uniformly, the external component of TEDE can be determined with a single DDE measurement on any part of the whole body. However, if the body is not irradiated uniformly, a single-dose measurement cannot determine the dose to the various organs and tissues for an accurate determination of the external EDE (EDEex). To ensure a conservative determination of TEDE, 10 CFR 20.1201(c) requires that the DDE component be determined from the part of the whole body receiving the highest exposure.
Authority to permit use of other weighting factors is found in footnote 2 to the table of organ weighting factors in 10 CFR 20.1003 states, [f]or the purpose of weighting the external whole body dose (for adding to the internal dose), a single weighting factor, of W T = 1.0, has been specified. The use of other weighting factors for external exposure will be approved on a case- by-case basis until such time as specific guidance is issued.
This approach to determining TEDE can be overly conservative for extremely non-uniform irradiations (i.e., when only a small portion of the whole body is irradiated). As discussed in the NRC Regulatory Issue Summaries 2002-06, 2003-04, and 2004-01, the NRC has approved several methods for determining EDEex, and has encouraged the use of EDEex in place of DDE for demonstrating compliance with the TEDE requirements in 10 CFR Part 20.
3.0 TECHNICAL EVALUATION
3.1 Evaluation The NRC staff has reviewed the technical approach for estimating EDEex provided in the standard. This multiple dosimetry method divides the whole body into seven separate compartments. Each compartment, or composite compartment (since the standard allows combining adjacent compartments), is monitored separately. The results of the dose measurement for each compartment are weighted with an associated compartment factor.
The resulting weighted doses are then summed to determine the EDEex for the whole body.
The compartment factors are listed in Table 1 of the standard. The factor for each compartment was developed by summing the stochastic weighting factors given in ICRP 26 (Part 20 organ weighting factors) for all the organs located within that compartment. For each tissue that resides in more than one compartment (e.g., red bone marrow), the weighting factor was apportioned between the compartments based on the fraction of the total mass of the tissue residing in each, using the information in ICRP 23.
The ANSI/HPS 13.41 multiple dosimeter method of determining EDEex is based on the assumptions that (1) the average dose to the tissues in each compartment can be reasonably measured (with one or more dosimeters), and (2) that the dose distribution across the compartment is sufficiently constant so that this average dose can be applied to each tissue in the compartment. The compartments defined in the standard are small enough so that under most normal exposure situations these assumptions are met and a single determination of DDE in each compartment is sufficient. However, this may not be the case in those unusual situations where a significant dose gradient exists across one or more compartments (particularly the thorax and abdomen compartments). In these cases, the number and placement of dosimeters in each compartment become critical to ensuring that the EDEex is not underestimated.
To ensure that the estimates of EDEex are conservative, the licensee has committed to measuring the dose to each compartment (or composite compartment) by locating the dosimeter, calibrated to DDE, at the highest exposed portion of that compartment. The dosimeter location for each compartment will be subject to the same criteria currently used for demonstrating compliance with 10 CFR 20.1201(c).
The licensee has stated that in most normal exposure situations they intend to provide one dosimeter for a combined thorax-abdomen composite compartment, consistent with the standard and their current multi-badging practice.
3.2 Regulatory Commitments The following table identifies the regulatory commitments made by Entergy.
List of Regulatory Commitments TYPE (Check one) SCHEDULED COMPLETION ONE- CONTINUING COMMITMENT DATE (If TIME COMPLIANCE Required)
ACTION Entergy will monitor the part of the whole body within each compartment (and/or composite compartment) that receives the highest dose.
Entergy is developing a fleet wide Nuclear Management Manual procedure EN-RP-204, x
Special Monitoring Requirements, for determining dosimeter selection and placement. This procedure guidance will be consistent with that found in NRC Inspection Procedure 71121.01, issue date 03/06/02.
Based on the NRCs approval of this request, Entergy will account for dose consistent with the guidance of the standard as follows:
The DDE for each compartment will be determined from dosimeters worn at that location. When no dosimeter is worn at a particular compartment, the DDE will be determined from the dosimeter positioned where the exposure is judged to be similar. x The assigned EDE will be the sum of each DDE measurement multiplied by its appropriate compartment factor.
The assigned lens dose equivalent (LDE) will be the higher of the head or chest dosimeters.
The assigned shallow dose equivalent (SDE) will be the highest of any whole body dosimeter.
The NRC staff finds that reasonable controls for the implementation and for subsequent evaluation of proposed changes pertaining to the above regulatory commitments are provided by the licensees administrative processes, including its commitment management program.
Should the licensee choose to incorporate a regulatory commitment into the emergency plan, Updated Final Safety Analysis Report, or other documents with established regulatory controls,
the associated regulations would define the appropriate change-control and reporting requirements. The NRC staff has determined that the commitments do not warrant the creation of regulatory requirements, which would require prior NRC approval of subsequent changes.
The NRC staff has agreed that Nuclear Energy Institute 99-04, Revision 0, Guidelines for Managing NRC Commitment Changes, provides reasonable guidance for the control of regulatory commitments made to the NRC staff (see Regulatory Issue Summary 2000-17, Managing Regulatory Commitments Made by Power Reactor Licensees to the NRC Staff, dated September 21, 2000). The commitments should be controlled in accordance with industry guidance or comparable criteria employed by a specific licensee. The NRC staff may choose to verify the implementation and maintenance of these commitments in a future inspection or audit.
4.0 CONCLUSION
S The NRC staff concludes that calculating TEDE using EDEex in place of DDE provides a more accurate estimate of the risk associated with the radiation exposures experienced by radiation workers at a nuclear power plant. The NRC staff finds that limiting TEDE such that EDEex + CEDE < 5 rem is consistent with the basis for the dose limits, and footnote 2 to the Organ Dose Weighting Factors table in 10 CFR Part 20.1003.
Additionally, the NRC staff concludes that the multiple dosimetry method to estimate EDEex using the weighting factors listed in Table 1 of the standard, as proposed by the licensee, is technically sound and is acceptable for the purposes of demonstrating compliance with the TEDE-based requirements in 10 CFR Part 20.
Therefore, based on the above discussion and the information provided by Entergy in its submittal, the NRC staff approves the use of the weighting factors provided in the ANSI HPS N13.41-1997 (the standard) for external radiation exposures when demonstrating compliance with total effective dose equivalent (TEDE), based on requirements in 10 CFR Part 20 for ANO-2 and JAF.
Principal Contributor: R. Pedersen Date: July 19, 2006
Arkansas Nuclear One cc:
Senior Vice President Vice President, Operations Support
& Chief Operating Officer Entergy Operations, Inc.
Entergy Operations, Inc. P. O. Box 31995 P. O. Box 31995 Jackson, MS 39286-1995 Jackson, MS 39286-1995 Wise, Carter, Child & Caraway Director, Division of Radiation P. O. Box 651 Control and Emergency Management Jackson, MS 39205 Arkansas Department of Health 4815 West Markham Street, Slot 30 Mr. Jeffrey S. Forbes Little Rock, AR 72205-3867 Site Vice President Arkansas Nuclear One Winston & Strawn Entergy Operations, Inc.
1700 K Street, N.W. 1448 S. R. 333 Washington, DC 20006-3817 Russellville, AR 72801 Senior Resident Inspector U.S. Nuclear Regulatory Commission P. O. Box 310 London, AR 72847 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 County Judge of Pope County Pope County Courthouse Russellville, AR 72801 September 2005
FitzPatrick Nuclear Power Plant cc:
Mr. Gary J. Taylor Ms. Charlene D. Faison Chief Executive Officer Manager, Licensing Entergy Operations, Inc. Entergy Nuclear Operations, Inc.
1340 Echelon Parkway 440 Hamilton Avenue Jackson, MS 39213 White Plains, NY 10601 Mr. John T. Herron Mr. Michael J. Colomb Sr. VP and Chief Operating Officer Director of Oversight Entergy Nuclear Operations, Inc. Entergy Nuclear Operations, Inc.
440 Hamilton Avenue 440 Hamilton Avenue White Plains, NY 10601 White Plains, NY 10601 Mr. Peter T. Dietrich Mr. David Wallace Site Vice President Director, Nuclear Safety Assurance Entergy Nuclear Operations, Inc. Entergy Nuclear Operations, Inc.
James A. FitzPatrick Nuclear Power Plant James A. FitzPatrick Nuclear Power Plant P.O. Box 110 P.O. Box 110 Lycoming, NY 13093 Lycoming, NY 13093 Mr. Kevin J. Mulligan Mr. James Costedio General Manager, Plant Operations Manager, Regulatory Compliance Entergy Nuclear Operations, Inc. Entergy Nuclear Operations, Inc.
James A. FitzPatrick Nuclear Power Plant James A. FitzPatrick Nuclear Power Plant P.O. Box 110 P.O. Box 110 Lycoming, NY 13093 Lycoming, NY 13093 Mr. Oscar Limpias Assistant General Counsel Vice President Engineering Entergy Nuclear Operations, Inc.
Entergy Nuclear Operations, Inc. 440 Hamilton Avenue 440 Hamilton Avenue White Plains, NY 10601 White Plains, NY 10601 Regional Administrator, Region I Mr. Christopher Schwarz U.S. Nuclear Regulatory Commission Vice President, Operations Support 475 Allendale Road Entergy Nuclear Operations, Inc. King of Prussia, PA 19406 440 Hamilton Avenue White Plains, NY 10601 Resident Inspector's Office James A. FitzPatrick Nuclear Power Plant Mr. John F. McCann U. S. Nuclear Regulatory Commission Director, Licensing P.O. Box 136 Entergy Nuclear Operations, Inc. Lycoming, NY 13093 440 Hamilton Avenue White Plains, NY 10601
FitzPatrick Nuclear Power Plant cc:
Mr. Charles Donaldson, Esquire Mr. Garrett D. Edwards Assistant Attorney General 814 Waverly Road New York Department of Law Kennett Square, PA 19348 120 Broadway New York, NY 10271 Mr. Michael Kansler President Mr. Peter R. Smith, President Entergy Nuclear Operations, Inc.
New York State Energy, Research, 440 Hamilton Avenue and Development Authority White Plains, NY 10601 17 Columbia Circle Albany, NY 12203-6399 Mr. Paul Eddy New York State Dept. of Public Service 3 Empire State Plaza Albany, NY 12223-1350 Oswego County Administrator Mr. Steven Lyman 46 East Bridge Street Oswego, NY 13126 Supervisor Town of Scriba Route 8, Box 382 Oswego, NY 13126 Mr. James H. Sniezek BWR SRC Consultant 5486 Nithsdale Drive Salisbury, MD 21801-2490 Mr. Michael D. Lyster BWR SRC Consultant 5931 Barclay Lane Naples, FL 34110-7306