[Federal Register Volume 63, Number 31 (Tuesday, February 17, 1998)]
[Notices]
[Pages 7843-7844]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-3835]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-247]


Consolidated Edison Company of New York, Inc., Indian Point 
Nuclear Generating Unit No. 2; Exemption

I

    Consolidated Edison Company of New York, Inc. (Con Edison or the 
licensee) is the holder of Facility Operating License No. DPR-26, which 
authorizes operation of Indian Point Nuclear Generating Unit No. 2 (the 
facility or IP2), at a steady-state reactor power level not in excess 
of 3071.4 megawatts thermal. The facility is a pressurized-water 
reactor located at the licensee's site in Westchester County, New York. 
The license provides, among other things, that the licensee is subject 
to all rules, regulations, and orders of the Commission now or 
hereafter in effect.

II

    In its letter dated October 7, 1997, the licensee requested that 
NRC exempt the unit from the application of the 1989 Edition of the 
American Society for Mechanical Engineers (ASME) Boiler and Pressure 
Vessel Code, Section XI, Appendix G (1989 methodology) as required by 
Title 10 of the Code of Federal Regulations, Part 50 Section 60 
(50.60), and 10 CFR 50.55a. As an alternative, the licensee proposed to 
use the version of ASME Section XI, Appendix G found in the 1996 
Addenda to the ASME Code (1996 methodology). The 1996 methodology is 
less conservative than the methodology in the 1989 Edition of the ASME 
Code. References in 10 CFR 50.60 and Appendix G require the use of a 
methodology at least as conservative as that found in Appendix G to the 
1989 Edition of Section XI of the ASME Code. Therefore, the staff must 
review and approve the 1996 methodology prior to use. The staff has 
reviewed the licensee's request and approves the use of the 1996 
methodology in lieu of the 1989 methodology for the construction of 
reactor vessel pressure-temperature (P-T) limits as described in 10 CFR 
Part 50, Appendix G. A methodology equivalent to the 1996 methodology 
was used in the licensee's P-T limits submittal dated October 2, 1996. 
The evaluation for the proposed P-T limits is issued as part of the 
amendment application.

III

    The NRC has established requirements in 10 CFR Part 50 to protect 
the integrity of the reactor coolant system pressure boundary. As a 
part of these, 10 CFR Part 50, Appendix G requires that P-T limits be 
established for reactor pressure vessels (RPVs) during normal operation 
and vessel hydrostatic testing. In particular, 10 CFR Part 50, Appendix 
G.IV.2.b. requires that these 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.'' 10 CFR 
50.55(a) specifies that the applicable ASME Code is the 1989 Edition. 
10 CFR 50.60, which broadly addresses the establishment of criteria for 
fracture prevention, states that ``proposed alternatives to the 
described requirements in Appendices G and H of this part or portions 
thereof may be used when an exemption is granted by the Commission 
under Sec. 50.12.'' The licensee used the methodology equivalent to the 
1996 methodology for its P-T limits application in lieu of the 1989 
methodology approved by the staff in the regulations. As part of this 
effort, the licensee has applied for an exemption to use the 1996 
methodology.

IV

    In the submittal, the exemption was requested under the special 
circumstances given in 10 CFR 50.12(a)(2)(ii). The provisions of this 
section state that special circumstances are present whenever 
``Application of the regulation in the particular circumstances * * * 
is not necessary to achieve the underlying purpose of the rule.'' The 
licensee explained that ``With the 1996 Addenda, Article G-2000 was 
revised to incorporate the most recent elastic solutions * * * These 
new solutions better characterize the conditions for irradiated vessels 
in the low temperature region where the thermal stresses and allowable 
pressure are low.'' The licensee also indicated that the 1996 
methodology contains the same ASME Section XI, Appendix G safety 
margin, which includes: (1) The 6:1 aspect ratio \1/4\ T flaw, (2) a 
factor of 2 on the membrane stress intensity factor, (3) the 
determination of material toughness from a reference curve based on 
dynamic and crack arrest data, and (4) margins on the materials' 
adjusted reference temperature based on Regulatory Guide 1.99, Revision 
2. Therefore, the licensee concluded that application of the 1996 
methodology would also meet the underlying intent of the regulations, 
namely to protect the integrity of the RPV from nonductile failure.
    The staff examined the licensee's rationale in support of the 
exemption request. From the regulatory perspective, the staff concurred 
that a condition for an exemption exists under 10 CFR 50.12(a)(2)(ii) 
because the 1996 methodology, which is more appropriate than the 1989 
methodology, became available recently and had been incorporated into 
the ASME Code. Consequently, application of the regulation in this 
particular instance is not necessary to achieve the underlying purpose 
of the rule.
    From the technical perspective, the staff agrees that this 
alternative method meets the underlying intent of the regulations. The 
staff has completed its review of the technical basis of the P-T limits 
submittal dated October 2, 1996. The evaluation of that submittal is 
issued along with Amendment No. 195 to License No. DPR-26. In that 
review, the staff examined the application of the 1996 methodology in 
detail, including a comparison of critical features of the 1989 and 
1996 methodologies using plant-specific data for the IP2 RPV, and 
confirmed the adequacy of the 1996 methodology. Hence, requesting the 
exemption under the special circumstances of 10 CFR 50.12(a)(2)(ii) was 
found to be appropriate, and the application of the 1996 methodology, 
or its equivalent, would meet the underlying intent of the regulations.
    On the basis of its review of the technical basis of the P-T limits 
submittal, the staff concludes that the use of a methodology equivalent 
to that contained in the 1996 Addenda of the ASME Code, which is less 
conservative than that specified in the regulation, meets the 
underlying intent of 10 CFR 50.60 and 10 CFR Part 50, Appendix G. The 
staff accepts that the explicit conservatism incorporated within the 
1996 Appendix G methodology will ensure that the RPV will be protected 
from non-ductile failure.

V

    For the foregoing reasons, the NRC staff has concluded that the 
licensee's proposed use of the alternative methodology in determining 
the P-T limits will not present an undue risk to public health and 
safety and is consistent with the common defense and security. The NRC 
staff has determined that there are special circumstances present, as 
specified in 10 CFR 50.12(a)(2)(ii), in that application of 10 CFR 
50.60 is not

[[Page 7844]]

necessary in order to achieve the underlying purpose of this 
regulation.
    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12, this exemption is authorized by law, will not present an undue 
risk to public health and safety, and is consistent with the common 
defense and security.
    Accordingly, the Commission hereby grants an exemption from 10 CFR 
50.60 so that this exemption permits the use of the methodology, or its 
equivalent, specified in Appendix G in the 1996 Addenda to Section XI 
of the ASME Code for developing P-T limits for IP2.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of the exemption will have no significant impact on the 
quality of the human environment (62 FR 6584).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 10th day of February, 1998.

    For the Nuclear Regulatory Commission.

Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 98-3835 Filed 2-13-98; 8:45 am]
BILLING CODE 7590-01-P