ML003781984

Exemption from the Requirements of 10 CFR Part 50, Section 50.60(a) and Appendix G

ML003781984
Person / Time
Site:	Limerick
Issue date:	03/15/2001
From:	Gratton C NRC/NRR/DLPM/LPD1
To:	Hutton J Exelon Generation Co
Gratton C, NRR/DLPM 415-1055
References
TAC MB0595
Download: ML003781984 (8)

Text

March 15, 2001 Mr. James A. Hutton Director-Licensing Exelon Generation Company Nuclear Group Headquarters Correspondence Control P.O. Box No. 160 Kennett Square, PA 19348

SUBJECT:

LIMERICK GENERATING STATION, UNIT 2 - ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT REGARDING EXEMPTION REQUEST TO USE THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) CODE CASE N-640 FOR GENERATION OF THE UPDATED PRESSURE-TEMPERATURE LIMIT CURVES (TAC NO. MB0595)

Dear Mr. Hutton:

Enclosed is a copy of the Environmental Assessment and Finding of No Significant Impact related to your application for exemption dated November 20, 2000, as supplemented on December 20, 2000. On January 12, 2001, the licenses held by PECO Energy Company (PECO) for Limerick Generating Station, Units 1 and 2, were transferred to Exelon Generation Company, LLC (Exelon). By letter dated January 30, 2001, Exelon requested that the U.S.

Nuclear Regulatory Commission continue to review and act upon all requests before the Commission which had been submitted by PECO.

The proposed exemption would exempt Exelon from the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix G, for generating the pressure-temperature (P-T) limit curves for Limerick Generating Station, Unit 2. The new P-T limits were developed using the methodology in the ASME Code Case N-640, Alternate Reference Fracture Toughness for Development of P-T Limit Curves for ASME Section XI, Division I, instead of using the methodology in 10 CFR Part 50, Appendix G.

The assessment is being forwarded to the Office of the Federal Register for publication.

Sincerely,

/RA/

Christopher Gratton, Sr. Project Manager, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-353

Enclosure:

Environmental Assessment cc w/encl: See next page

Mr. James A. Hutton March 15, 2001 Director-Licensing Exelon Generation Company Nuclear Group Headquarters Correspondence Control P.O. Box No. 160 Kennett Square, PA 19348

SUBJECT:

LIMERICK GENERATING STATION, UNIT 2 - ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT REGARDING EXEMPTION REQUEST TO USE THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) CODE CASE N-640 FOR GENERATION OF THE UPDATED PRESSURE-TEMPERATURE LIMIT CURVES (TAC NO. MB0595)

Dear Mr. Hutton:

Enclosed is a copy of the Environmental Assessment and Finding of No Significant Impact related to your application for exemption dated November 20, 2000, as supplemented on December 20, 2000. On January 12, 2001, the licenses held by PECO Energy Company (PECO) for Limerick Generating Station, Units 1 and 2, were transferred to Exelon Generation Company, LLC (Exelon). By letter dated January 30, 2001, Exelon requested that the U.S.

Nuclear Regulatory Commission continue to review and act upon all requests before the Commission which had been submitted by PECO.

The proposed exemption would exempt Exelon from the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix G, for generating the pressure-temperature (P-T) limit curves for Limerick Generating Station, Unit 2. The new P-T limits were developed using the methodology in the ASME Code Case N-640, Alternate Reference Fracture Toughness for Development of P-T Limit Curves for ASME Section XI, Division I, instead of using the methodology in 10 CFR Part 50, Appendix G.

The assessment is being forwarded to the Office of the Federal Register for publication.

Sincerely,

/RA/

Christopher Gratton, Sr. Project Manager, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-353

Enclosure:

Environmental Assessment cc w/encl: See next page DISTRIBUTION:

PUBLIC PDI-2 R/F RidsNrrDlpmLpdi RidsNrrDlpmLpdi2 MOBrien RidsNrrPmCGratton RidsOgcRp RidsAcrsAcnwMailCenter RidsRegionIMailCenter C Carpenter Accession Number: ML003781984 *See previous concurrence OFFICE PDI-2\PM PDI-1\LA EMCB OGC* RGEB* PDI-2\SC NAME CGratton MOBrien WBateman* MONeill CCarpenter JClifford DATE 3/6/01 3/6/01 2/1/01 3/1/01 2/8/01 3/14/01

Official Record Copy Limerick Generating Station, Units 1 and 2 cc:

J. W. Durham, Sr., Esquire Director-Site Engineering Sr. V.P. & General Counsel Limerick Generating Station Exelon Generation Company P.O. Box 2300 2301 Market Street Sanatoga, PA 19464 Philadelphia, PA 19101 Manager-Experience Assessment Manager-Limerick Licensing Limerick Generating Station Exelon Generation Company P.O. Box 2300 Nuclear Group Headquarters Sanatoga, PA 19464 Correspondence Control P.O. Box 160 Library Kennett Square, PA 19348 U.S. Nuclear Regulatory Commission Region I Mr. James D. von Suskil, Vice President 475 Allendale Road Limerick Generating Station King of Prussia, PA 19406 Post Office Box 2300 Sanatoga, PA 19464 Senior Manager-Operations Limerick Generating Station Plant Manager P.O. Box 2300 Limerick Generating Station Sanatoga, PA 19464 P.O. Box 2300 Sanatoga, PA 19464 Dr. Judith Johnsrud National Energy Committee Regional Administrator, Region I Sierra Club U.S. Nuclear Regulatory Commission 433 Orlando Avenue 475 Allendale Road State College, PA 16803 King of Prussia, PA 19406 Mr. James A. Hutton Senior Resident Inspector Director-Licensing U.S. Nuclear Regulatory Commission Exelon Generation Company Limerick Generating Station Nuclear Group Headquarters P.O. Box 596 Correspondence Control Pottstown, PA 19464 P. O. Box 160 Kennett Square, PA 19348 Chairman Board of Supervisors Mr. Jeffrey A. Benjamin of Limerick Township Licensing - Vice President 646 West Ridge Pike Exelon Generation Company Linfield, PA 19468 1400 Opus Place, Suite 900 Downers Grove, IL 60521 Chief-Division of Nuclear Safety PA Dept. of Environmental Resources P.O. Box 8469 Harrisburg, PA 17105-8469

7590-01-P UNITED STATES NUCLEAR REGULATORY COMMISSION EXELON GENERATION COMPANY DOCKET NO. 50-353 LIMERICK GENERATING STATION, UNIT 2 ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an exemption from certain requirements of Appendix G to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50) for Facility Operating License No. NPF-85, issued to Exelon Generation Company (Exelon or the licensee) for operation of the Limerick Generating Station, Unit 2 (Limerick Unit 2), located in Montgomery and Chester Counties in Pennsylvania.

ENVIRONMENTAL ASSESSMENT Identification of the Proposed Action:

Appendix G to 10 CFR Part 50, requires that pressure-temperature (P-T) limits be established for reactor pressure vessels (RPVs) during normal operating and hydrostatic or leak rate testing conditions. Specifically, 10 CFR Part 50, Appendix G, Section IV.A.2.a, states, The appropriate requirements on both the pressure-temperature limits and the minimum permissible temperature must be met for all conditions. Appendix G of 10 CFR Part 50 specifies that the requirements for these limits are the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Appendix G, limits.

To address provisions of amendments to the technical specifications P-T limits, the licensee requested in its submittal dated November 20, 2000, as supplemented December 20, 2000, that the Nuclear Regulatory Commission (NRC) staff exempt Limerick Unit 2 from application of specific requirements of Appendix G to 10 CFR Part 50, and

substitute use of ASME Code Case N-640. Code Case N-640 permits the use of an alternate reference fracture toughness (KIC fracture toughness curve instead of Kia fracture toughness curve) for reactor vessel materials in determining the P-T limits. Since the KIC fracture toughness curve shown in ASME Code,Section XI, Appendix A, Figure A-2200-1 (the KIC fracture toughness curve) provides greater allowable fracture toughness than the corresponding Kia fracture toughness curve of ASME Code,Section XI, Appendix G, Figure G-2210-01 (the Kia fracture toughness curve), using Code Case N-640 for establishing the P-T limits would be less conservative than the methodology currently endorsed by 10 CFR Part 50, Appendix G, and therefore, an exemption to Appendix G to apply the Code Case would be required.

The Need for the Proposed Action:

ASME Code Case N-640 is needed to revise the method used to determine the reactor coolant system (RCS) P-T limits, since continued use of the present curves unnecessarily restricts the P-T operating window. Since the RCS P-T operating window is defined by the P-T operating and test limit curves developed in accordance with the ASME Code,Section XI, Appendix G, procedure, continued operation of Limerick Unit 2 with these P-T curves without the relief provided by ASME Code Case N-640 would unnecessarily require the licensee to maintain the RPV at a temperature exceeding 212 oF in a limited operating window during the pressure test. Consequently, steam vapor hazards would continue to be one of the safety concerns for personnel conducting inspections in primary containment. Implementation of the proposed P-T curves, as allowed by ASME Code Case N-640, would eliminate steam vapor hazards by allowing inspections in primary containment to be conducted at a lower coolant temperature.

Environmental Impacts of the Proposed Action:

The proposed action would maintain an adequate margin of safety against brittle failure of the Limerick Unit 2 RPV.

The proposed action will not significantly increase the probability or consequences of accidents, no changes are being made in the types of any effluents that may be released offsite, and there is no significant increase in occupational or public radiation exposure.

Therefore, there are no significant radiological environmental impacts associated with the proposed action.

With regard to potential nonradiological impacts, the proposed action does not involve any historic sites. It does not affect nonradiological plant effluents and has no other environmental impact. Therefore, there are no significant nonradiological impacts associated with the proposed action.

Accordingly, the NRC concludes that there are no significant environmental impacts associated with the proposed action.

Alternatives to the Proposed Action:

As an alternative to the proposed action, the staff considered denial of the proposed action (i.e., the no-action alternative). Denial of the application would result in no change in current environmental impacts. The environmental impacts of the proposed action and the alternative action are similar.

Alternative Use of Resources:

This action does not involve the use of any resources not previously considered in the Final Environmental Statement for the Limerick Generating Station, Unit 2, dated April 1984.

Agencies and Persons Consulted:

In accordance with its stated policy, on January 19, 2001, the staff consulted with the Pennsylvania State official, David Ney of the Pennsylvania Department of Environmental

Protection, regarding the environmental impact of the proposed action. The State official had no comments.

FINDINGS OF NO SIGNIFICANT IMPACT On the basis of the environmental assessment, the NRC concludes that the proposed action will not have a significant effect on the quality of the human environment. Accordingly, the NRC has determined not to prepare an environmental impact statement for the proposed action.

For further details with respect to the proposed action, see the licensees letter dated November 20, 2000, as supplemented December 20, 2000. Documents may be examined, and/or copied for a fee, at the NRCs Public Document Room, located at One White Flint North, 11555 Rockville Pike (first floor) Rockville, Maryland. Publicly available records will be accessible electronically from the ADAMS Public Library component on the NRC Web site, http:\\www.nrc.gov (the Electronic Reading Room).

Dated at Rockville, Maryland, this 15th day of March 2001.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Christopher Gratton, Sr. Project Manager, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation