[Federal Register Volume 64, Number 233 (Monday, December 6, 1999)]
[Notices]
[Pages 68122-68124]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-31507]
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NUCLEAR REGULATORY COMMISSION
In the matter of Duke Energy Corporation (Oconee Nuclear Station,
Units 1, 2, and 3); Confirmatory Order Modifying Post-Three Mile Island
Requirements Pertaining to Containment Hydrogen Monitors
[Docket Nos. 50-269, 50-270, and 50-287; License Nos. DPR-38, DPR-47,
DPR-55]
I
Duke Energy Corporation (Duke or the licensee) is the holder of
Facility Operating License Nos. DPR-38, DPR-47, and DPR-55 issued by
the Nuclear Regulatory Commission (NRC or Commission) pursuant to 10
CFR Part 50. The licenses authorize the operation of Oconee Nuclear
Station (ONS), Units 1, 2, and 3, located in Oconee County, South
Carolina.
II
As a result of the accident at Three Mile Island, Unit 2 (TMI-2),
the NRC issued NUREG-0737, ``Clarification of TMI Action Plan
Requirements,'' in November 1980. Generic Letters 82-05 and 82-10,
issued on March 17 and May 5, 1982, respectively, requested licensees
of operating power reactors to furnish information pertaining to their
implementation of specific TMI Action Plan items described in NUREG-
0737. Orders were issued to licensees confirming their commitments made
in response to the generic letters. The Confirmatory Order that was
issued to Duke on March 18, 1983, required the licensee to implement
and maintain the various TMI Action Plan Items, including Item II.F.1,
Attachment 6 pertaining to monitoring of the hydrogen concentration in
the containment following a safety injection.
Significant improvements have been achieved since the TMI accident
in the areas of understanding risks associated with nuclear plant
operations and developing better strategies for managing the response
to potential severe accidents at nuclear power
[[Page 68123]]
plants. Recent insights pertaining to plant risks and severe accident
assessment tools have led the NRC staff to conclude that some TMI
Action Plan items can be revised without reducing, and perhaps
enhancing, the ability of licensees to respond to severe accidents. The
NRC's efforts to understand the risks associated with commercial
nuclear power plant operations more effectively and to reduce
unnecessary regulatory burden on licensees and the public have prompted
the NRC's decision to revise the post-TMI requirement to monitor
containment hydrogen concentration.
The Confirmatory Order of March 18, 1983, imposed requirements upon
the licensee to have continuous monitoring of containment hydrogen
concentration provided in the control room, as described by TMI Action
Plan Item II.F.1, Attachment 6. Information about hydrogen
concentration supports the licensee's assessments of the degree of core
damage and whether a threat to the integrity of the containment may be
posed by hydrogen gas combustion. TMI Action Item II.F.1, Attachment 6
states:
If an indication is not available at all times, continuous
indication and recording shall be functioning within 30 minutes of
the initiation of safety injection.
This requirement to have monitoring of the hydrogen concentration
in the containment within 30 minutes following the start of safety
injection has defined both design and operating characteristics for
hydrogen monitoring systems at nuclear power plants since the
implementation of NUREG-0737. In addition, the technical specifications
of most nuclear power plants and NRC regulation 10 CFR 50.44,
``Standards for combustible gas control system in light-water-cooled
power reactors,'' require availability of hydrogen monitors.
By letter dated August 4, 1999, Duke used the ANO confirmatory
order as guidance to request relief for the three Oconee units from the
requirement to have indication of hydrogen concentration in the
containment within 30 minutes of the initiation of safety injection.
Specifically, the licensee requested that risk-informed insights be
used to determine the functional requirements for monitoring of
containment hydrogen concentration that would allow extending the
monitoring requirement to more than 30 minutes following initiation.
The basis for this request was that the additional time would allow the
operators to complete their initial accident assessment and mitigation
duties before redirecting their attention to the relatively longer-term
recovery actions, such as actuating the hydrogen recombiners, that are
not needed for at least 24 hours.
Based on the staff's evaluation of the justification provided by
the licensee, and improved understanding of insights pertaining to
plant risks, severe accident assessment, and emergency planning since
the TMI-2 accident, the staff has concluded that the licensee's request
should be approved. Giving the licensee the flexibility and
responsibility for determining the appropriate time limit for
establishing monitoring of containment hydrogen concentration will
preclude control room personnel from being distracted from various
important tasks in the early phases of accident mitigation, while
allowing cognizant personnel, mostly outside the control room, to be
aware of hydrogen concentration based on a risk-informed functional
assessment at a reasonable time following an accident. Because the
appropriate balance between control room activities and longer-term
management of the response to severe accidents can best be determined
by the licensee, the NRC staff has determined that the licensee may
elect to adopt a risk-informed functional requirement in lieu of the
current 30-minute time limit for establishing monitoring of the
hydrogen concentration as imposed by the Order dated March 18, 1983,
and as described by TMI Action Item II.F.1, Attachment 6 in NUREG-0737.
The appropriate functional requirement is as follows:
Procedures shall be established for ensuring that monitoring of
hydrogen concentration in the containment atmosphere is available in
a sufficiently timely manner to support the implementation of the
Oconee Nuclear Station Emergency Plan (and related procedures) and
related activities such as guidance for severe accident management.
Hydrogen monitoring will be initiated based on: (1) The appropriate
priority for establishing monitoring of hydrogen concentration
within the containment in relation to other activities in the
control room, (2) the use of the monitoring of hydrogen
concentration by decision makers for severe accident management and
emergency response, and (3) insights from experience or evaluation
pertaining to possible scenarios that result in significant
generation of hydrogen that would be indicative of core damage or a
potential threat to the integrity of the containment building.
Affected licensing basis documents and other related documents will
be appropriately revised and/or updated in accordance with
applicable NRC regulations.
The licensee's Post Accident Monitoring Instrumentation Technical
Specifications and 10 CFR 50.44 require the licensee to maintain the
ability to monitor hydrogen concentration in the containment. However,
the details pertaining to the design and manner of operation of the
hydrogen monitoring system are determined by the licensee.
III
Accordingly, pursuant to Sections 103, 104b, 161b, 161i, 161o, and
182 of the Atomic Energy Act of 1954, as amended, and the Commission's
regulations in 10 CFR 2.202 and 10 CFR Part 50, It Is Hereby Ordered
that:
NRC License Nos. DPR-38, DPR-47, and DPR-55 are modified as
follows:
The licensee may elect to either maintain the 30-minute time
limit for monitoring of hydrogen in the containment, as described by
TMI Action Plan Item II.F.1, Attachment 6, in NUREG-0737 and
required by the Confirmatory Order of March 18, 1983, or modify the
time limit in the manner specified in Section II of this Order.
The Director, Office of Nuclear Reactor Regulation, may, in
writing, relax or rescind any of the above conditions upon
demonstration by the licensee of good cause.
IV
Any person adversely affected by this Confirmatory Order, other
than the licensee, may request a hearing within 20 days of its
issuance. Where good cause is shown, consideration will be given to
extend the time to request a hearing. A request for extension of time
must be made in writing to the Director, Office of Nuclear Reactor
Regulation, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555-
0001, and include a statement of good cause for the extension. Any
request for a hearing shall be submitted to the Secretary of the
Commission, U.S. Nuclear Regulatory Commission, ATTN: Chief,
Rulemakings and Adjudications Staff, Washington, D.C. 20555-0001.
Copies of the hearing request shall also be sent to the Director,
Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory
Commission, Washington, D.C. 20555-0001, to the Deputy Assistant
General Counsel for Hearings and Enforcement at the same address, to
the Regional Administrator, NRC Region II, Atlanta Federal Center, 23 T
85, 61 Forsyth Street, SW., Atlanta, Georgia 30303-3415, and to Anne W.
Cottington, Winston and Strawn, 1200 17th Street, NW., Washington, DC,
attorney for the licensee. If such a person requests a hearing, that
person will set forth with particularity the manner in which his
interest is adversely affected by this Order and will address the
criteria set forth in 10 CFR 2.714(d).
If the hearing is requested by a person whose interest is adversely
affected, the Commission will issue an Order
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designating the time and place of any hearing. If a hearing is held,
the issue to be considered at such hearing will be whether this
Confirmatory Order should be sustained.
In the absence of any request for hearing, or written approval of
an extension of time in which to request a hearing, the provisions
specified in Section IV above will be final 20 days from the date of
this Order without further order or proceedings. If an extension of
time for requesting a hearing has been approved, the provisions
specified in Section IV will be final when the extension expires if a
hearing request has not been received.
Dated at Rockville, Maryland, this 29th day of November 1999.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 99-31507 Filed 12-3-99; 8:45 am]
BILLING CODE 7590-01-P