[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]
=======================================================================
-----------------------------------------------------------------------
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
