[Federal Register Volume 68, Number 87 (Tuesday, May 6, 2003)]
[Notices]
[Pages 24024-24025]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-11159]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-440]
FirstEnergy Nuclear Operating Co., Perry Nuclear Power Plant;
Exemption
1.0 Background
The FirstEnergy Nuclear Operating Company (FENOC/ the licensee) is
the holder of Facility Operating License No. NPF-58 which authorizes
operation of Perry Nuclear Power Plant (PNPP). The license provides,
among other things, that the facility is subject to all rules,
regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC,
the Commission) now or hereafter in effect.
The facility consists of a boiling water reactor located on FENOC's
PNPP site, which is located in Lake County, Ohio.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR) part 50,
Appendix G 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 states that ``[t]he appropriate requirements on * *
* the pressure-temperature limits and 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 (ASME) Boiler and Pressure Vessel Code
(Code), Section XI, Appendix G Limits.
To address provisions of amendments to the technical specifications
P-T limits in the submittal dated June 4, 2002, the licensee requested
that the staff exempt PNPP from application of specific requirements of
10 CFR part 50, Sec. 50.60(a) and Appendix G, 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 provides greater allowable fracture toughness than the
[[Page 24025]]
corresponding KIa fracture toughness curve of ASME Code,
Section XI, Appendix G, Figure G-2210-1, using the Kic
fracture toughness, as permitted by Code Case N-640, in establishing
the P-T limits would be less conservative than the methodology
currently endorsed by 10 CFR part 50, appendix G. Considering this, an
exemption to apply the Code Case would be required by 10 CFR 50.60.
The licensee proposed to revise the P-T limits for PNPP using the
KIc fracture toughness curve, in lieu of the KIa
fracture toughness curve, as the lower bound for fracture toughness.
Use of the KIc curve in determining the lower bound
fracture toughness in the development of P-T operating limits curve is
more technically correct than the KIa curve since the rate
of loading during a heatup or cooldown is slow and is more
representative of a static condition than a dynamic condition. The
KIc curve appropriately implements the use of static
initiation fracture toughness behavior to evaluate the controlled
heatup and cooldown process of a reactor vessel. The staff has required
use of the initial conservatism of the KIa curve since 1974
when the curve was codified. This initial conservatism was necessary
due to the limited knowledge of RPV materials. Since 1974, additional
knowledge has been gained about RPV materials, which demonstrates that
the lower bound on fracture toughness provided by the KIa
curve is well beyond the margin of safety required to protect the
public health and safety from potential RPV failure.
In summary, the ASME Code, Section XI, Appendix G, procedure was
conservatively developed based on the level of knowledge existing in
1974, concerning RPV materials and the estimated effects of operation.
Since 1974, the level of knowledge about these topics has been greatly
expanded. The NRC staff concurs that this increased knowledge permits
relaxation of the ASME Code Section XI, Appendix G requirements by
applying the KIc fracture toughness, as permitted by Code
Case N-640, because compliance with ASME Code, Section XI, Appendix G
is not necessary to achieve the underlying purpose of 10 CFR 50.60 and
part 50, appendix G.
3.0 Discussion
Pursuant to 10 CFR 50.12, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of 10 CFR part 50, when (1) the exemptions are
authorized by law, will not present an undue risk to public health or
safety, and are consistent with the common defense and security; and
(2) when special circumstances are present. The staff accepts the
licensee's determination that an exemption would be required to approve
the use of Code Case N-640. The staff examined the licensee's rationale
to support the exemption request and concurred that the use of the Code
Case N-640 would meet the underlying intent of these regulations. Based
upon a consideration of the conservatism that is explicitly
incorporated into the methodologies of 10 CFR part 50, Appendix G;
Appendix G of the Code; and Regulatory Guide 1.99, ``Radiation
Embrittlement of Reactor Vessel Material,'' Revision 2, the staff
concluded that compliance with ASME Code, Appendix G is not necessary
to achieve the underlying purpose of 10 CFR 50.60 and 10 CFR part 50,
Appendix G because the application of Code Case N-640 as described
would provide an adequate margin of safety against brittle failure of
the RPV. This is also consistent with the determination that the staff
has reached for other licensees under similar conditions based on the
same considerations. Therefore, the staff concludes that requesting
exemption under the special circumstances of 10 CFR 50.12(a)(2)(ii) is
appropriate and that the methodology of Code Case N-640 may be used to
revise the P-T limits for PNPP.
4.0 Conclusion
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a), the exemption is authorized by law, will not endanger life or
property or common defense and security, and is, otherwise, in the
public interest. Therefore, the Commission hereby grants FENOC,
exemption from the requirements of 10 CFR part 50, Sec. 50.60(a) and
10 CFR part 50, Appendix G, for PNPP.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment (68 FR 13335).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 29th day of April 2003.
For the Nuclear Regulatory Commission.
John A. Zwolinski,
Director, Division of Licensing Project Management, Office of Nuclear
Reactor Regulation.
[FR Doc. 03-11159 Filed 5-5-03; 8:45 am]
BILLING CODE 7590-01-P