[Federal Register Volume 70, Number 52 (Friday, March 18, 2005)]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-5366]
NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-424 and 50-425]
Southern Nuclear Operating Company, Vogtle Electric Generating
Plant, Units 1 and 2; Environmental Assessment and Finding of No
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, for Renewed Facility
Operating License Nos. NPF-68 and NPF-81, issued to Southern Nuclear
Operating Company (the licensee), for operation of the Vogtle Electric
Generating Plant (Vogtle), Units 1, and 2, located in Waynesboro,
Georgia. 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: The proposed action would
exempt the licensee from the requirements of 10 CFR part 50, Appendix
G, footnote 2 to table 1, and allow the licensee to use the methodology
in Westinghouse Commercial Atomic Power Report (WCAP), WCAP-16142,
Revision 1, ``Reactor Vessel Closure Head/Vessel Flange Requirements
Evaluation for Vogtle Units 1 and 2,'' to justify eliminating the
reactor vessel/head flange region when determining pressure-temperature
(P-T) limits for the reactor vessel.
The proposed action is in accordance with the licensee's
application dated February 26, 2004, as supplemented on July 8, and
October 22, 2004.
The Need for the Proposed Action: Appendix G of 10 CFR part 50,
contains requirements for P-T limits for the primary system, and
requirements for metal temperature of the closure head flange and
vessel flange regions. The P-T limits are to be determined using the
methodology of American Society of Mechanical Engineers Boiler and
Pressure Vessel Code (ASME Code), Section XI, Appendix G, but the
flange temperature requirements are specified in 10 CFR part 50,
Appendix G. This rule states that the metal temperature at the closure
flange regions must exceed the material unirradiated RTNDT
by at least 120 [deg]F for normal operation when the pressure exceeds
20 percent of the pre-service hydrostatic test pressure.
This requirement was originally based on concerns about the
fracture margin in the closure flange region. During the boltup
process, outside surface stresses in this region typically reach over
70 percent of the steady state stress, without being at steady state
temperature. The margin of 120 [deg]F and the pressure limitation of 20
percent of hydrostatic pressure were developed in the mid-1970s using
the Kla fracture toughness to ensure that appropriate
margins would be maintained.
Improved knowledge of fracture toughness and other issues that
affect the integrity of the reactor vessel have led to the recent
change to allow the use of Klc in the development of P-T
curves, as contained in ASME Code Case N-640, ``Alternative Reference
Fracture Toughness for Development of P-T Limit Curves for Section XI,
Division 1.'' ASME Code Case, N-640 has been approved for use without
conditions by the NRC staff in Regulatory Guide 1.147, ``Inservice
Inspection Code Case Acceptability, ASME Section XI, Division 1,''
published in June 2003.
However, P-T limit curves can still produce operational constraints
by limiting the operational range available to the operator during
heatup and cooldown of the plant, especially when considering
requirements in the closure head flange and the vessel flange regions.
Implementing the P-T curves that use Klc material fracture
toughness without exempting the flange requirement of 10 CFR part 50,
Appendix G, would place a restricted
operating window in the temperature range associated with the closure
head flange and reactor vessel flange, without a commensurate increase
in plant safety.
Environmental Impacts of the Proposed Action: The NRC has completed
its safety evaluation of the proposed action and concludes that the
more conservative minimum temperature requirements related to footnote
(2) to Table 1 of 10 CFR part 50, Appendix G are not necessary to meet
the underlying intent of 10 CFR part 50, Appendix G, to protect the
Vogtle, Units 1 and 2 RPVs from brittle fracture during normal
operation under both core critical and core non-critical conditions and
RPV hydrostatic and leak test conditions.
The details of the NRC staffs safety evaluation will be provided in
the amendment and exemption that will be issued as part of letter to
the licensee approving the amendment and exemption to the regulation.
The proposed action will not significantly increase the probability
or consequence of accidents, no changes are being made in the types of
effluents that may be released off-site, 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 non-radiological impacts, the proposed
action does not have a potential to affect any historic sites. It does
not affect non-radiological plant effluents and has no other
environmental impact. Therefore, there are no significant
nonradiological environmental impacts associated with the proposed
Accordingly, the NRC concludes that there are no significant
environmental impacts associated with the proposed action.
Environmental Impacts of the Alternatives to the Proposed Action:
As an alternative to the proposed action, the NRC 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 resource than those previously considered in NUREG-
1087, ``Final Environmental Statement related to the operation of the
Vogtle Electric Generating Plant, Units 1 and 2,'' dated December 1985.
Agencies and Persons Consulted: On January 6, 2005, the NRC staff
consulted with the Georgia State official, Mr. Jim Hardeman of the
Department of Natural Resources, 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
For further details with respect to the proposed action, see the
licensee's letter dated February 26, 2004, as supplemented on July 8,
and October 22, 2004. 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 Agencywide Documents Access and
Management System (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 by
e-mail to [email protected].
Dated at Rockville, Maryland, this 10th day of March, 2005.
For the Nuclear Regulatory Commission.
Chief, Section 1, Project Directorate II, Division of Licensing Project
Management, Office of Nuclear Reactor Regulation.
[FR Doc. 05-5366 Filed 3-17-05; 8:45 am]
BILLING CODE 7590-01-P