[Federal Register Volume 64, Number 189 (Thursday, September 30, 1999)]
[Notices]
[Pages 52804-52805]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-25468]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-368]
Entergy Operations, Inc.; Arkansas Nuclear One, Unit No. 2
Environmental Assessment and Finding of No Significant Impact
The U.S. Nuclear Regulatory Commission (the Commission) is
considering issuance of an exemption from certain requirements of its
regulations for Facility Operating License No. NPF-6 issued to Entergy
Operations, Inc. (the licensee), for operation of Arkansas Nuclear One,
Unit 2 (ANO-2), located in Pope County, Arkansas.
Environmental Assessment
Identification of Proposed Action
The proposed action would exempt the licensee from the requirements
of Title 10 of the Code of Federal Regulations, Part 50 (10 CFR part
50), appendix R, Section III.G.2.c, regarding the fire protection of
the safe shutdown capability for equipment located below the 354 foot
elevation of the ANO-2 intake structure. The licensee is requesting an
exemption from the specific requirement to provide fire detectors and
an automatic fire suppression system to protect redundant trains of
safe shutdown equipment that are located in the same fire zone.
The proposed action is in accordance with the licensee's
application for exemption dated October 8, 1997, as supplemented by
letter dated February 25, 1999.
The purpose of 10 CFR part 50, appendix R, Section III.G.2, is to
ensure that adequate fire protection features are provided for
redundant cables or equipment located in the same fire area outside of
primary containment such that at least one of the redundant trains of
safe shutdown equipment will remain available during and after any
postulated fire in the plant to achieve and maintain safe shutdown
conditions. Section III.G.2.c requires the following means of
assurance:
Enclosure of cable and equipment and associated non-safety
circuits of one redundant train in a fire barrier having a 1-hour
rating. In addition, fire detectors and an automatic fire
suppression system shall be installed in the fire area.
The ANO-2 intake structure below the 354 foot elevation consists of
three service water intake bays, which contain service water (SW)
piping and conduits. The bays are approximately 7 feet by 32 feet and
are separated from one another by 2-foot thick, non-rated concrete
walls. The bays are separated from the ground level by an 18-inch
thick, non-rated concrete slab on metal decking. The floor of the bays
is typically covered with water 16 feet deep. The ceiling height is
approximately 14 feet above the normal pool level. Of the three bays,
only the ``A'' SW intake bay contains redundant cables. The licensee
stated that the total in-situ combustible loading is 3,469,060 BTUs,
which is equivalent to a fire severity to a standard fire duration of
less than 4 minutes. Each bay is administratively controlled as a
``confined space,'' thus limiting access by personnel during routine
operations and precluding the accumulation of combustibles. In
addition, the licensee's administrative procedures limit the transient
combustibles to 5 pounds unless personnel are continuously present in
the area. In such cases, the personnel could be either the craft
personnel responsible for using the combustible materials or a
continuous fire watch. Water to the bay is normally provided
[[Page 52805]]
through a sluice gate for the bays where the circulating pumps take
suction.
Service water is required to be available to supply cooling water
for various safe shutdown components including the diesel generators
and the shutdown cooling heat exchangers. Additionally, SW can be
aligned to the emergency feedwater system in the event that the desired
condensate source is depleted. The time critical function is to supply
cooling for the diesel generators. The licensee stated that, on the
basis of its calculations, the diesel generators (and therefore the SW
system components) are not required to be operated during the first 30
minutes of a postulated fire event. The licensee allows the operators
to manually align the SW system because the diesel generators are not
required during the first 30 minutes of a fire event and sufficient
time is available to complete the alignment.
The SW system consists of two independent seismic category 1 flow
paths that furnish cooling water to two independent trains of 100
percent capacity engineered safety feature equipment, and two non-
seismic category 1 flow paths. The SW system has three 100 percent
capacity pumps. One pump is dedicated to each of the two SW trains
while the third pump is designated as a swing pump and can be aligned
to either train. The two loops of the SW system are also electrically
independent with two separate divisions of electrical power designated
as the red and green train. The red train power for SW is aligned to
either SW pump 2P4A or SW pump 2P4B, while the green train power is
aligned to either SW pump 2P4C or SW pump 2P4B.
The four power cables associated with the 2P4A, 2P4B, and 2P4C SW
pumps interface with the ``A'' SW intake bay challenging the protection
criteria specified in Section III.G.2 of Appendix R. The red train
power to 2P4A is provided with a fire wrap rated as a 1-hour rated
barrier. The red train power to 2P4B is embedded in the concrete wall
of the ``A'' SW intake bay, which provides an equivalent 1-hour rated
fire barrier. The green train power to 2P4B is provided with a fire
wrap rated for a 1-hour barrier. The cables for the red train power to
2P4A and the green train power to 2P4B are routed together inside of a
protective moisture barrier. The green train power to 2P4C is routed
independently and is approximately 6 feet (horizontally) from the
protective moisture barrier providing some physical separation.
Therefore, based on the preceding discussion, this area would require
the addition of fire detectors and an automatic fire suppression system
in order to comply with the requirements of 10 CFR part 50, appendix R,
Section III.G.2.c.
Power and control cables for the sluice gates are also located in
the SW intake bays. Sluice gate valves 2CV1470-1, 2CV1472-5, and
2CV1474-2 are normally open, which corresponds to the safe shutdown
position. The redundant control cables are separated horizontally by
approximately 8 feet. As stated previously, the time critical function
of the SW system is to provide cooling to the diesel generators. The
licensee stated that if a fire were to cause the sluice gates to
spuriously close, adequate time would be available before service water
was required to manually realign any affected component.
The Need for the Proposed Action
The proposed action is needed because the addition of fire
detectors and an automatic fire suppression system to the SW intake
bays is considered infeasible due to the construction of the intake
structure and the fact that the room is partially water-filled during
normal conditions.
Environmental Impacts of the Proposed Action
The Commission has completed its evaluation of the proposed action
and concludes that there is no significant environmental impact if the
exemption is granted.
The proposed action will not increase the probability or
consequences of accidents, no changes are being made in the types of
any effluents that may be released off site, and there is no
significant increase in occupational or public radiation exposure.
Therefore, there are no significant radiological environmental impacts
associated with the proposed action.
With regards to potential nonradioactive impacts, the proposed
action does not involve any historic sites. It does not affect
nonradiological plant effluents and has no other environmental impacts.
Therefore, there are no significant nonradiological environmental
impacts associated with the proposed action.
Accordingly, the Commission concludes that there are no significant
environmental impacts associated with the proposed action.
Alternatives to the Proposed Action
As an alternative to the proposed action, the staff considered
denial of the requested action (i.e., the ``no-action'' alternative).
Based on the physical characteristics of the SW intake bays, the NRC
staff has determined that there is a low probability of occurrence for
a fire event in the ANO-2 intake structure below the 354 foot
elevation. This low probability of occurrence combined with the lack of
combustible material, administrative controls, and the fire protection
features provided is sufficient to show adequate protection for
redundant equipment in the SW system. Therefore, the features
associated with the ANO-2 Intake Structure below the 354 foot elevation
are sufficient to achieve the underlying purpose of Appendix R, Section
III.G.2.c. Therefore, denial of the application would result in no
change in the current environmental impacts. The environmental impacts
of the proposed action and the alternative action are similar.
Alternative Use of Resources
This action does not involve the use of any resources not
previously considered in the Final Environmental Statement for Arkansas
Nuclear One, Unit 2.
Agencies and Persons Consulted
In accordance with its stated policy, on June 24, 1999, the staff
consulted with the Arkansas State official, Mr. Bernie Bevill,
Supervisor, Quality and Evaluation Section, Division of Radiation
Control and Emergency Management, regarding the environmental impact of
the proposed action. The State official had no comments.
Finding of No Significant Impact
On the basis of the environmental assessment, the Commission
concludes that the proposed action will not have a significant effect
on the quality of the human environment. Accordingly, the Commission
has determined not to prepare an environmental impact statement for the
proposed action.
For further details with respect to the proposed action, see the
licensee's letter dated October 8, 1997, as supplemented by letter
dated February 25, 1999. These letters are available for public
inspection at the Commission's Public Document Room, The Gelman
Building, 2120 L Street, NW., Washington, DC, and at the local public
document room at the Tomlinson Library, Arkansas Tech University,
Russellville, Arkansas.
For the Nuclear Regulatory Commission.
Robert A. Gramm,
Chief, Section 1, Project Directorate IV & Decommissioning, Division of
Licensing Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 99-25468 Filed 9-29-99; 8:45 am]
BILLING CODE 7590-01-P
