ML063350042

Quad and Timi - Application to Use Weighting Factors for External Exposure

ML063350042
Person / Time
Site:	Dresden, Peach Bottom, Oyster Creek, Byron, Braidwood, Limerick, Clinton, Quad Cities, LaSalle, Crane
Issue date:	12/20/2006
From:	Marshall M Plant Licensing Branch III-2
To:	Crane C Exelon Generation Co
Gratton C, NRR, DORL, 415-1055
References
TAC MC9247, TAC MC9248, TAC MC9249, TAC MC9250, TAC MC9251, TAC MC9252, TAC MC9253, TAC MC9254, TAC MC9255, TAC MC9256, TAC MC9257, TAC MC9258, TAC MC9259, TAC MC9260, TAC MC9261, TAC MC9262, TAC MC9263
Download: ML063350042 (16)

Text

December 20, 2006 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

BRAIDWOOD STATION, UNIT NOS. 1 AND 2; BYRON STATION, UNIT NOS. 1 AND 2; CLINTON POWER STATION, UNIT 1; DRESDEN NUCLEAR POWER STATION, UNITS 1, 2, AND 3; LASALLE COUNTY STATION, UNITS 1 AND 2; LIMERICK GENERATING STATION, UNITS 1 AND 2; OYSTER CREEK NUCLEAR GENERATING STATION; PEACH BOTTOM ATOMIC POWER STATION, UNITS 1, 2, AND 3; QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2; AND THREE MILE ISLAND NUCLEAR STATION, UNIT 1 -

APPLICATION TO USE WEIGHTING FACTORS FOR EXTERNAL EXPOSURE (TAC NOS. MC9247 THROUGH MC9263)

Dear Mr. Crane:

By letter dated December 14, 2005, as supplemented by letters dated April 18, September 6, and December 13, 2006, Exelon Generation Company, LLC and AmerGen Energy Company, LLC (the licensees), requested approval for the use of weighting factors for the whole body, other than 1.0, for determining the effective dose equivalent (EDE) from external exposures. In accordance with footnote 2 to the Table of Organ Dose Weighting Factors in Title 10 of the Code of Federal Regulations (10 CFR), Section 20.1003, this EDE will be added to the committed effective dose equivalent from internal exposures when demonstrating compliance with the total effective dose equivalent requirements in 10 CFR Part 20.

On the basis of its review, the Nuclear Regulatory Commission (NRC) staff finds the licensees request acceptable. The enclosed safety evaluation documents the staffs findings.

C. Crane Please contact me at (301) 415-8707 or Christopher Gratton at (301) 415-1055, if you have any questions on this matter.

Sincerely,

/RA/

Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-456, and STN 457; STN 50-454 and STN 50-455; 50-461; 50-10, 50-237, 50-249, and 72-37; STN 50-373 and STN 50-374; 50-352 and 50-353; 50-219 and 72-15; 50-171, 50-277, 50-278, and 72-1027; 50-254 and 50-265; and 50-289

Enclosure:

Safety Evaluation cc w/encl: See next page

C. Crane Please contact me at (301) 415-8707 or Christopher Gratton at (301) 415-1055, if you have any questions on this matter.

Sincerely,

/RA/

Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-456, and STN 457; STN 50-454 and STN 50-455; 50-461; 50-10, 50-237, 50-249, and 72-37; STN 50-373 and STN 50-374; 50-352 and 50-353; 50-219 and 72-15; 50-171, 50-277, 50-278, and 72-1027; 50-254 and 50-265; and 50-289

Enclosure:

Safety Evaluation cc w/encl: See next page DISTRIBUTION:

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• See SE dated NRR-106 OFFICE NRR/LPL3-2/PM NRR/LPL3-2/LA NRR/IHPB/BC OGC NRR/LPL3-2/BC NAME CGratton:mw EWhitt TFrye*

BPoole MMarshall DATE 12/13/2006 12/13/2006 10 /23 /2006 12/14/06 12/20/2006 OFFICIAL RECORD COPY

Byron/Braidwood Stations cc:

Dwain W. Alexander, Project Manager Westinghouse Electric Corporation Energy Systems Business Unit Post Office Box 355 Pittsburgh, PA 15230-0355 Howard A. Learner Environmental Law and Policy Center of the Midwest 35 East Wacker Dr., Suite 1300 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office 4448 N. German Church Road Byron, IL 61010-9750 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351 Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950 Chairman, Ogle County Board Post Office Box 357 Oregon, IL 61061 Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, IL 61107 Attorney General 500 S. Second Street Springfield, IL 62701 Illinois Emergency Management Agency Division of Disaster Assistance &

Preparedness 110 East Adams Street Springfield, IL 62701-1109 Plant Manager - Byron Station Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Site Vice President - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 U.S. Nuclear Regulatory Commission Braidwood Resident Inspectors Office 35100 S. Rt. 53, Suite 79 Braceville, IL 60407 County Executive Will County Office Building 302 N. Chicago Street Joliet, IL 60432 Plant Manager - Braidwood Station Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Ms. Bridget Little Rorem Appleseed Coordinator 117 N. Linden Street Essex, IL 60935 Document Control Desk - Licensing Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Site Vice President - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Senior Vice President - Operations Support Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

Byron/Braidwood Stations cc:

Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Regulatory Assurance - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Manager Regulatory Assurance - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Assistant General Counsel Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348 Vice President - Regulatory & Legal Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Braidwood/Byron Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President - Midwest Operations Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Clinton Power Station, Unit 1 cc:

Manager Regulatory Assurance - Clinton AmerGen Energy Company, LLC Clinton Power Station RR3, Box 228 Clinton, IL 61727-9351 Site Vice President - Clinton Power Station AmerGen Energy Company, LLC Clinton Power Station RR 3, Box 228 Clinton, IL 61727-9351 Plant Manager - Clinton Power Station AmerGen Energy Company, LLC Clinton Power Station RR 3, Box 228 Clinton, IL 61727-9351 Resident Inspector U.S. Nuclear Regulatory Commission RR #3, Box 229A Clinton, IL 61727 Chairman of DeWitt County c/o County Clerks Office DeWitt County Courthouse Clinton, IL 61727 J. W. Blattner Project Manager Sargent & Lundy Engineers 55 East Monroe Street Chicago, IL 60603

Dresden and Quad Cities Nuclear Power Stations cc:

Site Vice President - Dresden Nuclear Power Station Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 Plant Manager - Dresden Nuclear Power Station Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 Manager Regulatory Assurance - Dresden Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 U.S. Nuclear Regulatory Commission Dresden Resident Inspectors Office 6500 N. Dresden Road Morris, IL 60450-9766 Chairman Grundy County Board Administration Building 1320 Union Street Morris, IL 60450 Regional Administrator U.S. NRC, Region III 801 Warrenville Road Lisle, IL 60532-4351 Site Vice President - Quad Cities Exelon Generation Company, LLC 22710 206th Avenue N.

Cordova, IL 61242-9740 Plant Manager - Quad Cities Exelon Generation Company, LLC 22710 206th Avenue N.

Cordova, IL 61242-9740 Regulatory Assurance Manager - Quad Cities Exelon Generation Company, LLC 22710 206th Avenue N.

Cordova, IL 61242-9740 Quad Cities Resident Inspectors Office U.S. Nuclear Regulatory Commission 22712 206th Avenue N.

Cordova, IL 61242 David C. Tubbs MidAmerican Energy Company One River Center Place 106 E. Second, P.O. Box 4350 Davenport, IA 52808-4350 Vice President - Law and Regulatory Affairs MidAmerican Energy Company One River Center Place 106 E. Second Street P.O. Box 4350 Davenport, IA 52808 Chairman Rock Island County Board of Supervisors 1504 3rd Street Rock Island County Office Building Rock island, IL 61201

LaSalle County Station, Units 1 and 2 cc:

Site Vice President - LaSalle County Station Exelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757 Plant Manager - LaSalle County Station Exelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757 Phillip P. Steptoe, Esquire Sidley and Austin One First National Plaza Chicago, IL 60603 Assistant Attorney General 100 W. Randolph St. Suite 12 Chicago, IL 60601 Chairman LaSalle County Board 707 Etna Road Ottawa, IL 61350 Chairman Illinois Commerce Commission 527 E. Capitol Avenue, Leland Building Springfield, IL 62706 Robert Cushing, Chief, Public Utilities Division Illinois Attorney General's Office 100 W. Randolph Street Chicago, IL 60601 Zion Nuclear Power Station cc:

Decommissioning Plant Manager - Zion Exelon Generation Company, LLC 101 Shiloh Boulevard Zion, IL 60099-2797 Regulatory Assurance Engineer - Zion Exelon Generation Company, LLC 101 Shiloh Boulevard Zion, IL 60099-2797

Limerick Generating Station, Unit Nos. 1 and 2 cc:

Site Vice President Limerick Generating Station Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Plant Manager Limerick Generating Station Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Regulatory Assurance Manager - Limerick Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Director Licensing and Regulatory Affairs Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Manager Licensing Limerick Generating Station Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Correspondence Control Desk Exelon Generation Company, LLC P.O. Box 160 Kennett Square, PA 19348 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Senior Resident Inspector U.S. Nuclear Regulatory Commission Limerick Generating Station P.O. Box 596 Pottstown, PA 19464 Library U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Director, Bureau of Radiation Protection Pennsylvania Dept. of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469 Chairman Board of Supervisors of Limerick Township 646 West Ridge Pike Linfield, PA 19468 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803

Oyster Creek Nuclear Generating Station cc:

Site Vice President - Oyster Creek Nuclear Generating Station AmerGen Energy Company, LLC P.O. Box 388 Forked River, NJ 08731 Senior Vice President of Operations AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-N Kennett Square, PA 19348 Kathryn M. Sutton, Esquire Morgan, Lewis, & Bockius LLP 1111 Pennsylvania Avenue, NW Washington, DC 20004 Kent Tosch, Chief New Jersey Department of Environmental Protection Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625 Mayor of Lacey Township 818 West Lacey Road Forked River, NJ 08731 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 445 Forked River, NJ 08731 Director - Licensing and Regulatory Affairs AmerGen Energy Company, LLC Correspondence Control P.O. Box 160 Kennett Square, PA 19348 Manager Licensing - Oyster Creek Exelon Generation Company, LLC Correspondence Control P.O. Box 160 Kennett Square, PA 19348 Regulatory Assurance Manager Oyster Creek AmerGen Energy Company, LLC P.O. Box 388 Forked River, NJ 08731 Ron Bellamy, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 Correspondence Control Desk AmerGen Energy Company, LLC 200 Exelon Way, KSA 1--1 Kennett Square, PA 19348 Oyster Creek Nuclear Generating Station Plant Manager AmerGen Energy Company, LLC P.O. Box 388 Forked River, NJ 08731

Peach Bottom Atomic Power Station, Unit Nos. 2 and 3 cc:

Site Vice President Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Plant Manager Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Regulatory Assurance Manager Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Resident Inspector U.S. Nuclear Regulatory Commission Peach Bottom Atomic Power Station P.O. Box 399 Delta, PA 17314 Mr. Roland Fletcher Department of Environment Radiological Health Program 2400 Broening Highway Baltimore, MD 21224 Board of Supervisors Peach Bottom Township 545 Broad Street Ext.

Delta, PA 17314-9203 Mr. Richard McLean Power Plant and Environmental Review Division Department of Natural Resources B-3, Tawes State Office Building Annapolis, MD 21401 Manager-Financial Control & Co-Owner Affairs Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, NJ 08038-0236 Manager Licensing-Peach Bottom Atomic Power Station Exelon Generation Company, LLC 200 Exelon Way, KSA -3E Kennett Square, PA 19348

TMI, Unit 1 cc:

Site Vice President - Three Mile island Nuclear Station 1 AmerGen Energy Company, LLC P.O. Box 480 Middletown, PA 17120 Chairman Board of County Commissioners of Dauphin County Dauphin County Courthouse Harrisburg, PA 17120 Chairman Board of Supervisors of Londonderry Township R.D. #1, Geyers Church Road Middletown, PA 17057 Senior Resident Inspector (TMI-1)

U.S. Nuclear Regulatory Commission P.O. Box 219 Middletown, PA 17057 Plant Manager - Three Mile Island Nuclear Station, Unit 1 AmerGen Energy Company, LLC P. O. Box 480 Middletown, PA 17057 Regulatory Assurance Manager - Three Mile Island Nuclear Station, Unit 1 AmerGen Energy Company, LLC P.O. Box 480 Middletown, PA 17057 Michael A. Schoppman Framatome ANP Suite 705 1911 North Ft. Myer Drive Rosslyn, VA 22209 Vice President, General Counsel and Secretary AmerGen Energy Company, LLC 2301 Market Street, S23-1 Philadelphia, PA 19101 Eric Epstein TMI Alert 4100 Hillsdale Road Harrisburg, PA 17112

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE APPROVAL TO USE WEIGHTING FACTORS FOR EXTERNAL RADIATION EXPOSURES FOR THE EXELON/AMERGEN FLEET OF NUCLEAR POWER PLANTS, DOCKET NOS. STN 50-456 AND STN 50-457; STN 50-454 AND STN 50-455; 50-461 50-10, 50-237, 50-249, and 72-37; STN 50-373 AND STN 50-374; 50-352 AND 353; 50-219 AND 72-15; 50-171, 50-277, 50-278, AND 72-1027; 50-254 AND 265; AND 50-289

1.0 INTRODUCTION

By letter to the Nuclear Regulatory Commission (NRC) dated December 14, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession no. ML053560041), as supplemented by letters dated April 18, 2006 (ADAMS Accession No. ML061110339),

September 6, 2006 (ADAMS Accession No. ML062580143), and December 13, 2006 (ADAMS Accession No. ML063530361), Exelon Generation Company, LLC (Exelon) and AmerGen Energy Company, LLC (AmerGen) (the licensees) requested an approval to use weighting factors provided in the American National Standards Institute (ANSI) HPS N13.41-1997 (the Standard, Reference 1), for external radiation exposures when demonstrating compliance with total effective dose equivalent (TEDE) based requirements in Title 10 of the Code of Federal Regulations (10 CFR) Part 20 (Reference 2), for the Exelon/AmerGen fleet of nuclear power plants. The effect of granting this request would be to allow the licensees 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 (Reference 3). 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 whether 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.

Section 20.1003 of 10 CFR defines effective dose equivalent (EDE or HE) as ?the sum of the products of the dose equivalent to the organ or tissue (HT) and the weighting factors (WT) applicable to each of the body organs or tissues that are irradiated (HE = ' WT HT).

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 10 CFR 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).

The TEDE is defined in 10 CFR 20.1003 as the ?sum of the deep-dose equivalent (for external exposures) and the committed effective dose equivalent (for internal exposures).

TEDE = deep-dose equivalent (DDE) + 'T WT HT, 50 (CEDE).

The organ dose weighting factor (WT) for an organ or tissue is the proportion of the risk of stochastic effects resulting from irradiation of that organ or tissue to the total risk of stochastic effects when the whole body is irradiated uniformly. There are 8 weighting factors defined in 10 CFR 20.1003. 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 th external EDE (EDEex). To ensure a conservative determination of TEDE, 10 CFR 20.1201(c) requires that the DDE component to be determined for the part of the whole body receiving the highest exposure.

In addition, footnote 2 to the table of Organ Dose Weighting Factors in 10 CFR 20.1003, states that, ?[f]or the purpose of weighting the external whole body dose (for adding to the internal dose), a single weighting factor, WT = 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.

The conservative approach to determining TEDE can be overly conservative for non-uniform irradiations (e.g., when only a small portion of the whole body is irradiated). As discussed in 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

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 is 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 (i.e., red bone marrow), the weighting factor is apportioned between the compartments based on the fraction of the total mass of the tissue residing in each, using the information in ICRP Publication 26.

The NRC staffs review of the Standard determined that the Standards criteria for monitoring each compartment are not sufficiently clear to ensure that a conservative estimate of EDEex will result. Although not stated in the Standard, fundamental to this compartment method of determining EDEex are the following assumptions: 1) the average dose to the tissues in each compartment can be reasonably measured (with one or more dosimeters), and 2) the dose distribution across the compartment is sufficiently constant so that this average dose can be applied to each tissue in the compartment. The body compartments defined in the Standard are such 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 of the compartments. This can be a particular concern for the larger compartments, such as the thorax or abdomen, or if two or more compartments are combined (as allowed by the Standard) to form a larger, composite, compartment. In these cases, the number and placement of dosimeters in each compartment become critical to ensuring that the EDEex is not underestimated.

In response to this concern, the licensees have 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. This composite compartment will be called the chest compartment. To ensure that the estimates of EDEex are conservative, the licensees have committed to measuring the dose to each compartment (or composite compartment) by locating the dosimeter at the highest exposed part of that compartment. The dosimeter location for each compartment will be subject to the same criteria they currently use for demonstrating compliance with 10 CFR 20.1201(c). In addition, the dosimeters will be calibrated to measure DDE. The licensees commitments are summarized in Section 4.0 below.

4.0 COMMITMENTS COMMITMENT COMMITMENT DATE OR OUTAGE Exelon/AmerGen procedures will be revised to require that when using the weighting factors in Table 1 of ANSI/HPS N13.41-1997, dosimetry is to be placed at the highest exposed part of the compartment or composite compartment.

Upon implementation of NRC approved use of revised weighting factors.

Exelon/AmerGen procedures will be revised to require an evaluation of the dose gradient across the compartment when determining dosimeter placement. The deep dose equivalent will be assigned to the part receiving the highest dose.

Upon implementation of NRC approved use of revised weighting factors.

The NRC staff finds that reasonable controls for the implementation and for subsequent evaluation of proposed changes pertaining to the above regulatory commitments are best provided by the licensees administrative processes, including its commitment management program (see Regulatory Issue Summary 2000-017, Managing Regulatory Commitments Made by Power Reactor Licensees to the NRC Staff, ADAMS Accession No. ML003741774).

As such, the above regulatory commitments do not warrant the creation of regulatory requirements (items requiring prior NRC approval of subsequent changes).

5.0 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 defining TEDE such that:

TEDE = EDEex + CEDE is consistent with the basis for the dose limits, and footnote 2 to the Table of Organ Dose Weighting Factors in 10 CFR 20.1003.

Additionally, the NRC staff concludes that the multiple dosimetry method to estimate EDEex using the weighting factors listed in Table 1 of ANSI/HPS 13.41-1997, as proposed by the licensees, is technically sound and is acceptable for the purposes of demonstrating compliance with the TEDE-based requirements in 10 CFR Part 20, subject to the regulatory commitments set forth above.

6.0 REFERENCES

1.

ANSI-HPS N13.41-1997, An American National Standard - Criteria for Performing Multiple Dosimetry, Health Physics Society, December 1996.

2.

10 CFR Part 20, Title 10 Code of Federal Regulations Part 20 - Standards for Protection Against Radiation.

3.

ICRP 26, ICRP Publication 26 - Recommendations of the International Commission on Radiation Protection, January 17, 1977, Pergamon Press.

Principal Contributor: R. Pedersen Date: December 20, 2006