[Federal Register Volume 76, Number 239 (Tuesday, December 13, 2011)]
[Notices]
[Pages 77563-77565]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-31902]


-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-335; NRC-2011-0194]


Florida Power & Light Company; St. Lucie Plant, Unit No. 1; 
Exemption

1.0 Background

    The Florida Power & Light Company (FPL, the licensee) is the holder 
of Renewed Facility Operating License No. DPR-67, which authorizes 
operation of St. Lucie Plant, Unit No. 1 (St. Lucie, Unit 1). The 
license provides, among other things, that the facility is subject to 
all rules, regulations, and orders of the Nuclear Regulatory Commission 
(NRC, or the Commission) now or hereafter in effect. The facility 
consists of two pressurized-water reactors located in Jensen Beach, 
Florida. However, this exemption is applicable only to St. Lucie, Unit 
1.
    By letter dated December 15, 2010, FPL submitted a License 
Amendment Request (LAR) to increase the licensed core power level for 
St. Lucie, Unit 1, from 2700 megawatts thermal (MWt) to 3020 MWt. As 
part of the LAR, the licensee also proposed a revision of the pressure-
temperature (P-T) operating limits for St. Lucie, Unit 1.
    The above LAR referenced a topical report that stated that the 
proposed methodology for the P-T curves did not meet some of the 
requirements of Title 10 of the Code of Federal Regulations (10 CFR) 
part 50, Appendix G, thus requiring an exemption pursuant to 10 CFR 
50.12. By letter dated March 3, 2011, the licensee responded to a 
request for additional information to the above LAR and also submitted 
a request for the subject exemption.

2.0 Request/Action

    Part 50 of 10 CFR, Appendix G, ``Fracture Toughness Requirements,'' 
which is invoked by 10 CFR 50.60, requires that P-T limits be 
established for the reactor coolant pressure boundary during normal 
operating and hydrostatic or leak rate testing conditions. 
Specifically, 10 CFR Part 50, Appendix G, Section IV.A.2, states that 
``[t]he appropriate requirements on both the pressure-temperature 
limits and the minimum permissible temperature must be met for all 
conditions,'' and ``[t]he pressure-temperature limits identified as 
`ASME [American Society for Mechanical Engineers] Appendix G limits' in 
Table 3 require that the limits must be at least as conservative as 
limits obtained by following the methods of analysis and the margins of 
safety of Appendix G of Section XI of the ASME Code [Boiler and 
Pressure Vessel Code].'' The regulations in 10 CFR part 50, Appendix G 
also specify the use of the applicable editions and addenda of the ASME 
Code, Section XI, which are incorporated by reference in 10 CFR 50.55a. 
In the 2009 Edition of 10 CFR, the 1977 Edition through the 2004 
Edition of the ASME Code, Section XI are incorporated by reference in 
10 CFR 50.55a. Finally, 10 CFR 50.60(b) states that, ``[p]roposed 
alternatives to the described requirements in Append[ix] G of this part 
or portions thereof may be used when an exemption is granted by the 
Commission under [10 CFR] 50.12.''
    In conjunction with the LAR for an extended power uprate (EPU), the 
licensee proposed to revise the P-T limits but did not propose to 
relocate the P-T limits from the Technical Specifications to a 
Pressure-Temperature Limits Report (PTLR). However, in Section 2.1.2 of 
the Licensing Report for the St. Lucie, Unit 1, EPU (Agencywide 
Documents Access and Management System (ADAMS) Accession No. 
ML103560429), the licensee referenced the basis document for the 
revised P-T limits. The basis document, included as Appendix G to the 
Licensing Report, is Westinghouse Commercial Atomic Power report WCAP-
17197-NP Revision 0, ``St. Lucie Unit 1 RCS [reactor coolant system] 
Pressure and Temperature Limits and Low-Temperature Overpressure 
Protection Report [LTOP] for 54 Effective Full-Power Years'' (ADAMS 
Accession No. ML103560511), which references Combustion Engineering 
(CE) Owners Group Topical Report CE NPSD-683-A, Revision 6, 
``Development of a RCS Pressure and Temperature Limits Report for the 
Removal of P-T Limits and LTOP Requirements from the Technical 
Specifications'' (ADAMS Accession No. ML011350387), as the methodology 
for determining the P-T limits.
    By letter dated March 3, 2011 (ADAMS Accession No. ML110660300), 
the licensee submitted a request for exemption from 10 CFR part 50, 
Appendix G, regarding the P-T limits calculation. The licensee 
requested an exemption from the requirements of 10 CFR 50, Appendix G, 
to use the methodology of CE NPSD-683-A, Revision 6 as the basis for 
the developing the P-T limits. Specifically, the licensee requested an 
exemption from the requirements of 10 CFR 50, Appendix G, Section 
IV.A.2, because the P-T limits developed for St. Lucie, Unit 1, use a 
finite element method to determine the KIm factors.
    The NRC staff evaluated the specific PTLR methodology in CE NPSD-
683, Revision 6. This evaluation was documented in the NRC safety 
evaluation (SE) of March 16, 2001 (ADAMS Accession No. ML010780017), 
which specified additional licensee actions that are necessary to 
support a licensee's adoption of CE NPSD-683, Revision 6. The final 
approved version of this report was reissued as CE NPSD-683-A, Revision 
6, which included the NRC SE and the required additional action items 
as an attachment to the report. One of the additional specified actions 
(21) stated, ``(applicable only if the CE NSSS [nuclear steam 
supply system] methods for calculating KIm and 
KIt factors, as stated in Section 5.4 of CE NPSD-683, 
Revision 6, are being used as the basis for generating the P-T limits 
for their facilities) apply for an exemption against requirements of 
Section IV.A.2.of Appendix G to part 50 to apply the CE NSSS methods to 
their P-T curves.'' The action item further stated that, ``This is 
consistent with the `note' on page 5-15 of CE NPSD-683, Revision 6. 
Exemption requests to apply the CE NSSS to the generation of P-T limit 
curves should be submitted pursuant to the provision of 10 CFR 50.60(b) 
and will be evaluated on a case-by-case basis against the exemption 
request acceptance criteria of 10 CFR 50.12.''
    An exemption to use the methodology of CE NPSD-683-A to calculate 
the KIt factors is no longer necessary because editions and 
addenda of the ASME Code, Section XI, that have been incorporated by 
reference into 10 CFR 50.55a subsequent to the issuance of the final SE 
of CE NPSD-683-A, allow methods for determining the KIt 
factors that are equivalent to the methods described in CE NPSD-683-A.
    If a licensee proposes to use the methodology in CE NPSD-683-A, 
Revision 6, for the calculation of KIm, an exemption is 
required, since the methodology for the calculation of KIm 
values in CE NPSD-683-A, Revision 6, cannot be shown to be equally or 
more conservative than the methodology for the determination of 
KIm provided in editions and addenda of the ASME Code, 
Section XI, Appendix G, through the 2004 Edition. Therefore, the 
licensee submitted an exemption request, consistent with the 
requirements of 10 CFR 50.12 and 50.60, to apply the KIm 
calculational methodology of CE NPSD-

[[Page 77564]]

683-A, Revision 6 in the development of the St. Lucie, Unit 1, P-T 
limits. During the NRC staff's review of CE NPSD-683, Revision 6, the 
NRC staff evaluated the KIm calculational methodology of 
that report versus the methodologies for the calculation of 
KIm given in the ASME Code, Section XI, Appendix G. In the 
NRC's March 16, 2001, SE the staff noted, ``[t]he CE NSSS methodology 
does not invoke the methods in the 1995 edition of Appendix G to the 
Code for calculating KIm factors, and instead applies FEM 
[finite element modeling] methods for estimating the KIm 
factors for the RPV [reactor pressure vessel] shell * * * the staff has 
determined that the KIm calculation methods apply FEM 
modeling that is similar to that used for the determination of the 
KIt factors [as codified in the ASME Code, Section XI, 
Appendix G]. The staff has also determined that there is only a slight 
nonconservative difference between the P-T limits generated from the 
1989 edition of the ASME Code, Section XI, Appendix G, and those 
generated from CE NSSS methodology as documented in CE/ABB Evaluation 
063-PENG-ER-096, Revision 00, `Technical Methodology Paper Comparing 
ABB/CE PT Curve to ASME Section III, Appendix G,' dated January 22, 
1998 (ADAMS Accession No. ML100500514, nonproprietary version). The 
staff considers that this difference is reasonable and that it will be 
consistent with the expected improvements in P-T generation methods 
that have been incorporated into the 1995 edition of Appendix G to the 
Code.'' This conclusion regarding the comparison between the CE NSSS 
methodology and the 1995 Edition of the ASME Code, Section XI, Appendix 
G, methodology also applies to the 2004 Edition of the ASME Code, 
Section XI, Appendix G, methodology because there were no significant 
changes in the method of calculating the KIm factors 
required by the ASME Code, Section XI, Appendix G, between the 1995 
edition (through 1996 addenda) and the 2004 editions of the ASME Code. 
In summary, the staff concluded in its March 16, 2001, SE that the 
calculation of KIm using the CE NPSD-683, Revision 6 
methodology would lead to the development of P-T limit curves that may 
be slightly nonconservative with respect to those that would be 
calculated using the ASME Code, Section XI, Appendix G, methods, and 
that such a difference was to be expected with the development of more 
refined calculational techniques. Furthermore, the staff concluded in 
its March 16, 2001, SE that P-T limit curves that would be developed 
using the methodology of CE NPSD-683, Revision 6, would be adequate for 
protecting the RPV from brittle fracture under all normal operating and 
hydrostatic/leak test conditions.

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, are consistent with the common defense and security; and (2) 
when special circumstances are present.

Authorized by Law

    This exemption allows the use of an alternative methodology for 
calculating flaw stress intensity factors in the RPV due to membrane 
stress from pressure loadings in lieu of meeting the requirements in 10 
CFR 50.60 and 10 CFR Part 50, Appendix G. As stated above, 10 CFR 50.12 
allows NRC to grant exemptions from the requirements of 10 CFR Part 50. 
In addition, the granting of the exemption will not result in violation 
of the Atomic Energy Act of 1954, as amended, or the Commission's 
regulations. Therefore, the exemption is authorized by law.

No Undue Risk to Public Health and Safety

    The underlying purpose of 10 CFR 50.60 and 10 CFR Part 50, Appendix 
G, is to provide an acceptable margin of safety against brittle failure 
of the RCS during any condition of normal operation to which the 
pressure boundary may be subjected over its service lifetime. 
Appropriate P-T limits are necessary to achieve this underlying 
purpose. The licensee's alternative methodology for establishing the P-
T limits and the LTOP setpoints is described in CE NPSD-683-A, Revision 
6, which has been approved by the NRC staff. Based on the above, no new 
accident precursors are created by using the alternative methodology. 
Thus, the probability of postulated accidents is not increased. Also, 
based on the above, the consequences of postulated accidents are not 
increased. In addition, the licensee used an NRC-approved methodology 
for establishing P-T limits and minimum permissible temperatures for 
the RPV. Therefore, there is no undue risk to the public health and 
safety.

Consistent With Common Defense and Security

    The exemption results in changes to the plant by allowing an 
alternative methodology for calculating flaw stress intensity factors 
in the RPV. This change to the calculation of stress intensity factors 
in the RPV material has no negative implications for security issues. 
Therefore, the common defense and security is not impacted by this 
exemption.

Special Circumstances

    Special circumstances, pursuant to 10 CFR 50.12(a)(2)(ii), are 
present in that continued operation of St. Lucie, Unit 1, with P-T 
limit curves developed in accordance with the ASME Code, Section XI, 
Appendix G, is not necessary to achieve the underlying purpose of 10 
CFR Part 50, Appendix G. Application of the KIm 
calculational methodology of CE NPSD-683-A, Revision 6, in lieu of the 
calculational methodology specified in the ASME Code, Section XI, 
Appendix G, provides an acceptable alternative evaluation procedure 
that will continue to meet the underlying purpose of 10 CFR Part 50, 
Appendix G. The underlying purpose of the regulations in 10 CFR Part 
50, Appendix G, is to provide an acceptable margin of safety against 
brittle failure of the reactor coolant system during any condition of 
normal operation to which the pressure boundary may be subjected over 
its service lifetime. Based on the staff's March 16, 2001, SE regarding 
CE NPSD-683, Revision 6, and the licensee's rationale to support the 
exemption request, the staff determined that an exemption is required 
to approve the use of the KIm calculational methodology of 
CE NPSD-683-A, Revision 6. The staff concludes that the application of 
the KIm calculational methodology of CE NPSD-683-A, Revision 
6, for St. Lucie, Unit 1, provides sufficient margin in the development 
of RPV P-T limit curves such that the underlying purpose of the 
regulations (10 CFR Part 50, Appendix G) continues to be met. 
Therefore, the NRC staff concludes that the exemption requested by the 
licensee is justified based on the special circumstances of 10 CFR 
50.12(a)(2)(ii), ``[a]pplication of the regulation in the particular 
circumstances would not serve the underlying purpose of the rule or is 
not necessary to achieve the underlying purpose of the rule.'' Based 
upon a consideration of the conservatism that is incorporated into the 
methodologies of 10 CFR Part 50, Appendix G, and ASME Code, Section XI, 
Appendix G, the staff concludes that application of the KIm

[[Page 77565]]

calculational methodology of CE NPSD-683-A, Revision 6, as described, 
would provide an adequate margin of safety against brittle failure of 
the RPV. Therefore, the staff concludes that the exemption is 
appropriate under the special circumstances of 10 CFR 50.12(a)(2)(ii), 
and that the application of the KIm calculational 
methodology of CE NPSD-683-A, Revision 6, is acceptable for use as the 
basis for generating the St. Lucie, Unit 1, P-T limits.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the exemption is authorized by law, will not present an undue 
risk to the public health and safety, and is consistent with the common 
defense and security. Also, special circumstances are present. 
Therefore, the Commission hereby grants FPL an exemption from the 
requirements of 10 CFR Part 50, Appendix G, to allow application of the 
KIm calculational methodology of CE NPSD-683-A, Revision 6, 
as the basis for the St. Lucie, Unit 1, P-T limits.
    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 (76 FR 53497; dated August 26, 2011). 
This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 5th day of December 2011.

For the Nuclear Regulatory Commission.
Michele G. Evans,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. 2011-31902 Filed 12-12-11; 8:45 am]
BILLING CODE 7590-01-P