The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an exemption from Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix G, “Fracture Toughness Requirements,” for Facility Operating License Nos. NPF-41, NPF-51, and NPF-74, issued to the Arizona Public Service Company (APS, or the licensee), for operation of the Palo Verde Nuclear Generating Station (PVNGS, the facility), Units 1, 2, and 3, respectively, located in Maricopa County, Arizona. Therefore, as required by 10 CFR 51.21, the NRC is issuing this environmental assessment and finding of no significant impact.
Identification of the Proposed Action
By letter dated February 19, 2009, as supplemented by letter dated December 22, 2009, the licensee submitted a license amendment request where, among other changes, the licensee requested the use of an alternate methodology for calculating the stress intensity factor KIM due to internal pressure loading. As specified in the NRC safety evaluation approving Combustion Engineering (CE) Topical Report NPSD-683-A, Revision 6, “Development of a RCS [Reactor Coolant System] Pressure and Temperature Limits Report (PTLR) for the removal of P-T [Pressure Temperature] Limits and LTOP [Low-Temperature Overpressure Protection] Requirements from the Technical Specifications,” dated March 16, 2001, the licensee's application included a request for an exemption from the requirements of 10 CFR Part 50, Appendix G for pressure temperature (P-T) limits, since the alternate methodology applies the CE Nuclear Steam Supply System method Start Printed Page 8150for calculating KIM stress intensity values.
The proposed action would exempt the licensee from certain requirements of Appendix G to 10 CFR Part 50 to allow the application of the methodology in CE NPSD-683-A, Revision 6, for the calculation of flaw stress intensity factors due to internal pressure loadings (KIM).
The Need for the Proposed Action
The exemption is needed to allow the licensee to use an alternate methodology to meet the fracture toughness requirements for the reactor coolant pressure boundary. In the considering the exemption request, the staff has determined that, pursuant to 10 CFR 50.12(a)(2)(ii), the application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule, based on the alternate methodology proposed by the licensee. The proposed action would revise the currently-approved methodology for P-T limit calculations to incorporate the methodology approved for use in CE NPSD-683-A, Revision 6. The topical report allows the use of an alternate methodology to calculate the flaw stress intensity factors due to internal pressure loadings (KIM). Specifically, the exemption is needed because the methodology in CE NPSD-683-A, Revision 6, could not be shown to be conservative with respect to the methodology for the determination of KIM provided in Editions and Addenda of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section XI, Appendix G, through the 1995 Edition and 1996 Addenda (the latest Edition and Addenda of the ASME Code which had been incorporated into 10 CFR 50.55a at the time of the staff's review of CE NPSD-683-A, Revision 6). Therefore, the licensee submitted an exemption request, consistent with the requirements of 10 CFR 50.60, to apply the KIM calculational methodology of CE NPSD-683-A, Revision 6, as part of the PVNGS, Units 1, 2, and 3, PTLR methodology.
Environmental Impacts of the Proposed Action
The NRC has completed its evaluation of the proposed action and concludes that the use of the alternate methodology described above would provide an adequate margin of safety against brittle failure of the reactor pressure vessels at PVNGS, Units 1, 2 and 3. The proposed change does not involve any replacement or modification of plant components and no changes are proposed in the operation of PVNGS. Therefore the staff concludes that the use of an alternate methodology as described in the licensee's request would not significantly affect plant safety and would not have a significant adverse affect on the probability of an accident occurring.
The proposed action will not result in any non-radiological impacts or radiological impacts. The proposed action does not result in changes to the operation of the plant and supporting facilities, land use, or water use, nor does it result in changes to the quality or quantity of non-radiological and radiological effluents. No impacts are expected to the air or ambient air quality. No impacts are expected to aquatic or terrestrial habitats or species, or to threatened, endangered, or protected species. No impacts are expected to historic and cultural resources, or to socioeconomic resources. Accordingly, the NRC concludes that there are no significant environmental impacts associated with the proposed action.
The details of the staff's safety evaluation will be provided in the exemption to 10 CFR 50, Appendix G, which will allow the use of the methodology in Topical Report CE NPSD-683-A, Revision 6, to calculate the flaw stress intensity factors due to internal pressure loadings (KIM). The exemption will be issued in a future letter to the licensee.
Environmental Impacts of the 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
The action does not involve the use of any different resources than those previously considered in the Final Environmental Statement for the Palo Verde Nuclear Generating Station, Units 1, 2, and 3, NUREG-0841, dated February 1982.
Agencies and Persons Consulted
In accordance with its stated policy, on February 12, 2010, the staff consulted with the Arizona State official, Mr. Aubrey Godwin of the Arizona Radiation Regulatory Agency, regarding the environmental impact of the proposed action. The State official had no comments.
Finding 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 licensee's letters dated February 19 and December 22, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML090641014 and ML10040069, respectively). Documents may be examined, and/or copied for a fee, at the NRC's Public Document Room (PDR), located at One White Flint North, Public File Area O1 F21, 11555 Rockville Pike (first floor), Rockville, Maryland. Publicly available records will be accessible electronically from the ADAMS Public Electronic Reading Room on the Internet at the NRC Web site, http://www.nrc.gov/reading-rm/adams.html. Persons who do not have access to ADAMS or who encounter problems in accessing the documents located in ADAMS should contact the NRC PDR Reference staff by telephone at 1-800-397-4209 or 301-415-4737, or send an e-mail to email@example.com.Start Signature
Dated at Rockville, Maryland, this 16th day of February 2010.
For the Nuclear Regulatory Commission.
James R. Hall,
Senior Project Manager, Plant Licensing Branch IV, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation.
[FR Doc. 2010-3496 Filed 2-22-10; 8:45 am]
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