[Federal Register Volume 63, Number 73 (Thursday, April 16, 1998)]
[Notices]
[Pages 18943-18944]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-10103]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-286]
In the Matter of Power Authority of the State of New York;
(Indian Point Nuclear Generating Unit No. 3); Exemption
I
The Power Authority of the State of New York (the licensee) is the
holder of Facility Operating License No. DPR-64, which authorizes
operation of the Indian Point Nuclear Generating Unit No. 3 (IP3). The
license provides that the licensee is subject to all rules,
regulations, and orders of the U.S. Nuclear Regulatory Commission (the
Commission) now or hereafter in effect.
The facility is a pressurized water reactor located in Westchester
County, New York.
II
The Code of Federal Regulations, 10 CFR 50.60, states that the
reactor coolant pressure boundaries for light water reactors must meet
the fracture toughness and material surveillance program requirements
set forth in Appendices G and H to 10 CFR Part 50.
By letter dated November 3, 1997, the licensee requested an
exemption from 10 CFR 50.60 to allow the use of the American Society of
Mechanical Engineers (ASME) Code Case N-514 for the determination of
the low temperature overpressurization system (LTOP) parameters in
place of the margins required by Appendix G to 10 CFR Part 50. The Code
Case limits the overpressurization system (OPS) curve to not greater
than 110% of the pressure determined to satisfy Appendix G, paragraph
G-2215 of ASME Code, Section XI, Division 1, further reduced to allow
for static head due to elevation differences and dynamic head effect of
the operation of the four reactor coolant pumps. The Code Case also
allows some latitude in determining the OPS enable temperature.
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 and as stated in Appendix G, ``The
appropriate requirements on * * * the pressure-temperature limits * * *
must be met for all conditions.'' The Code of Federal
[[Page 18944]]
Regulations, 10 CFR 50.60, 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.'' Since the licensee wishes to use Code Case N-514 as
opposed to the requirements of Appendix G, an exemption to the
regulations is necessary.
IV
In referring to 10 CFR 50.12 on specific exemptions, the licensee
cited special circumstance 10 CFR 50.12(a)(2)(ii) on achieving the
underlying purpose of the regulations, 10 CFR 50.12(a)(iii) on undue
hardship, and 10 CFR 50.12 (a)(iv) on good faith compliance as their
bases for requesting this exemption.
The licensee noted in support of the 10 CFR 50.12(a)(2)(ii)
criterion that the underlying purpose of the subject regulations is to
establish limits to protect the reactor vessel from brittle failure
during low temperature operation and that the OPS provides a physical
means of protecting these limits. The licensee proposed that
establishing the OPS pressure setpoint per the N-514 provisions such
that the vessel pressure would not exceed 110 percent of the P-T limit
allowables ``* * * * reduces the unnecessary actuation of the LTOP
system due to normal pressure surges that occur during low temperature
operation * * * while maintaining acceptable safety margins.'' The
staff determined that the ``acceptable level of safety'' using N-514
was based on the conservatism which has been explicitly incorporated
into the procedure for developing the P-T limits. This procedure,
referenced from Appendix G to Section XI of the ASME Code, includes the
following conservatisms: (1) a safety factor of 2 on the pressure
stresses; (2) a margin factor applied to RTNDT using
Regulatory Guide 1.99, Revision 2; (3) an assumed \1/4\ T flaw with a
6:1 aspect ratio; (4) a limiting material toughness based on dynamic
and crack arrest data.
The licensee noted in support of the 10 CFR 50.12(a)(iii) criterion
that, as the reactor vessel ages, the operating window for the LTOP
system is reduced. This reduced window could lead to inadvertent
actuation of the LTOP system which could, in turn, lead to rapid
pressure changes.
The licensee noted in support of the 10 CFR 50.12(a)(iv) criterion
that the plant is currently in conformance with 10 CFR 50.60 and that
relief is being requested in order to maintain sufficient operating
margin. The licensee also notes that the staff, in Draft Regulatory
Guide 1050, has proposed to endorse Code Case N-514.
The staff reviewed the licensee's rationale to support the
exemption request on the basis of 10 CFR 50.12(a)(iii) and the staff
concluded that the use of Code Case N-514 would also meet the
underlying intent of the regulations. Based upon a consideration of the
conservatism which is explicitly defined in the Appendix G methodology
(as listed Section 3.0 above), the staff concluded that permitting the
OPS setpoint to be established such that the vessel pressure would not
exceed 110 percent of the P-T limits would provide an adequate margin
of safety against brittle failure of the reactor vessel. This is also
consistent with the determination that the staff has reached for other
licensees under similar conditions based on the same considerations.
The staff reviewed the licensee's rationale to support the
exemption on the basis of 10 CFR 50.12(a)(iii). The staff has
previously granted exemptions for other licensees under similar
circumstances; therefore, the staff has determined that operating with
a reduced LTOP window would result in an undue hardship that is
significantly in excess of that incurred by others similarly situated.
The staff reviewed the licensee's rationale to support the
exemption on the basis of 10 CFR 50.12(a)(iv) and has determined that
the licensee has made a good faith effort to comply with the
regulation.
V
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 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.
Therefore, the Commission hereby grants the following exemption.
The Power Authority of the State of New York is exempt from the
requirements of 10 CFR 50.60 in that they are permitted to use Code
Case N-514 in place of the safety margins required by Appendix G to 10
CFR Part 50 to determine the LTOP parameters.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will have no significant impact on the
quality of the human environment (63 FR 17903).
This exemption is effective upon issuance. Dated at Rockville,
Maryland, this 10th day of April 1998.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 98-10103 Filed 4-15-98; 8:45 am]
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