[Federal Register Volume 60, Number 9 (Friday, January 13, 1995)]
[Notices]
[Pages 3281-3283]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-923]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-286]
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, among other things, that the licensee is subject to
all rules, regulations, and orders of the Nuclear Regulatory Commission
(the Commission) now or hereafter in effect.
The facility consists of a pressurized water reactor at the
licensee's site located in Westchester County, New York.
II
By letter dated November 30, 1993, as supplemented July 6, 1994,
the licensee requested an exemption from the requirements of 10 CFR
Part 50, Appendix R, Section III.G.2, which specifies requirements to
ensure that one train of redundant equipment necessary to achieve and
maintain hot shutdown remains free of fire damage. Specifically, the
licensee requested an exemption from Section III.G.2.f such that the
redundant wide-range steam [[Page 3282]] generator water level sensing
lines and the redundant pressurizer level sensing lines, located inside
containment, need not be separated by noncombustible radiant energy
shields.
The steam generator water level and the pressurizer water level are
parameters needed to achieve and maintain safe shutdown following a
fire. The wide-range steam generator water level sensing lines and the
pressurizer level sensing lines transmit pressure changes from the
steam generator and the pressurizer to their respective pressure
transmitters.
The redundant wide-range steam generator sensing lines are routed
within 20 feet of each other at elevation 48'-0'' (Fire Zone 70A). The
lines run vertically along a wall from elevation 48'-0'' to their
respective transmitters, which are located in a common instrument rack
at elevation 68'-0'' (Fire Zone 70A). At this point, the sensing lines
are separated by about 2 feet. The three redundant pressurizer level
sensing lines are spaced about 8 feet apart at elevation 117'-0'' (Fire
Zone 86A). From here the lines are routed down the outside of the
concrete structure surrounding the pressurizer. At elevation 95'-0''
(Fire Zone 86A) the lines penetrate the floor and continue down the
inside of the crane wall to the elevation of their respective low level
sensing lines. At this point, each reference leg is paired with its
variable leg. The redundant lines then run in opposite directions along
the inside of the crane wall until they penetrate the wall at
approximately the 65'-0'' elevation (Fire Zone 70A). The sensing lines
enter a common instrument rack on elevation 68'-0'' (Fire Zone 87A).
The cables inside containment are rubber insulated with a glass/
asbestos braided jacket. As reported in a fire test that was
transmitted to the NRC by letter dated November 22, 1982, and accepted
in NRC Safety Evaluation dated February 2, 1984, the cables will not
propagate a fire to any significant degree.
Fire detection inside containment in Fire Zones 70A, 77A, and 71A
at elevation 68'0'' includes four photo electric smoke detectors, one
mounted above each reactor coolant pump. Fire suppression at this
elevation includes nine carbon dioxide extinguishers and three water
hose stations. In Fire Zones 70A and 71A, at elevation 46 feet, there
are four water hoses, five carbon dioxide extinguishers, and three
photoelectric smoke detectors located in the penetration area.
Section III.G.2 of Appendix R to 10 CFR Part 50 provides options
for the protection of cables and equipment and associated nonsafety
circuits of redundant trains located inside noninerted containments.
Certain segments of the wide-range steam generator water level sensing
lines and the pressurizer level sensing lines are not provided with the
level of fire protection required by Section III.G.2 of Appendix R to
10 CFR Part 50. The licensee has requested an exemption from Section
III.G.2.f which specifies that such equipment be separated by a
noncombustible radiant energy shield.
III
Pursuant to 10 CFR 50.12, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of 10 CFR Part 50 when (1) the exemptions are
authorized by law, will not present an undue risk to public health and
safety, and are consistent with the common defense and security and (2)
when special circumstances are present as set forth in 10 CFR
50.12(a)(2).
The staff was concerned that the lack of radiant energy shields
between these redundant trains of instrument sensing lines could result
in erroneous pressurizer or steam generator level indications in the
event of a fire. The wide-range steam generator sensing lines are
routed within 20 feet of each other starting at elevation 48'-0'' (Fire
Zone 70A) up into the transmitter at elevation 68'-0'' (Fire Zone 70A).
With the exception of reactor coolant pump lube oil (discussed below),
the maximum fire severity of the in-situ combustibles located within 20
feet of the wide-range steam generator sensing lines is less than 6
minutes. A fire involving these combustibles would be of limited
magnitude and extent. In addition, the smoke and hot gases from the
fire would be directed upwards into the higher elevations of the
containment and away from the sensing lines. Therefore, the staff does
not believe that these in-situ combustibles present a threat to the
sensing lines. A transient combustible fire appears to be the only type
of fire that could directly expose the wide-range steam generator
lines, because transient combustibles can only be placed in the
vicinity of the lines at the instrument rack where they converge
(Instrument Rack 21). The licensee has addressed this potential
transient fire exposure by providing a radiant energy shield in the
front of the instrument rack that will protect one channel of steam
generator wide-level instrumentation from a floor-based transient
combustible fire at elevation 68'-0''.
The three pressurizer sensing lines are spaced approximately 8 feet
apart from their initiation point at elevation 117'-0'' (Fire Zone 86A)
down the outside of the concrete structure surrounding the pressurizer
down to the 95'-0'' level. After penetrating the 95'-0'' level (Fire
Zone 86A) they are routed down the inside of the crane wall (Fire Zone
70A) to the elevation of their respective low-level sensing lines. The
reference leg is paired with its variable leg. The redundant lines then
run in opposite directions along the inside of the crane wall until
they penetrate the wall at about the 65'-0'' elevation (Fire Zone 70A).
Their route is terminated upon entering a common instrument rack (Fire
Zone 87A).
A fire involving the cables in the vicinity of the pressurizer
sensing lines could expose the sensing lines to elevated temperatures.
However, it is expected that a cable fire in the vicinity of the
sensing lines will not damage the sensing lines because of the large
open containment and the limited potential for flame propagation along
the cables.
Each of the four reactor coolant pumps is provided with a
seismically designed oil collection system that collects oil from
pressurized and unpressurized oil leakage sites from the reactor
coolant pump lube oil system. This provides reasonable assurance that a
lube oil leak will be contained by the oil collection system. The oil
collection system should prevent escaping oil from reaching potential
hot surfaces which will significantly reduce the probability of a fire.
Fire detection and manual fire suppression is available in the
vicinity of the sensing lines. In the event of a fire, it is expected
that the detector will alarm and the fire brigade will respond to
extinguish the fire in its incipient stages.
On the basis of its evaluation, the NRC staff concludes that a
postulated fire in the vicinity of the redundant wide-range steam
generator water level sensing lines and the redundant pressurizer level
sensing lines in containment Fire Zones 70A, 77A, and 86A would not
prevent the operators from achieving and maintaining safe shutdown. The
NRC staff also concludes that the level of fire protection provided for
the wide-range steam generator water level sensing lines and the
pressurizer level sensing lines is adequate and that the lack of
radiant energy shields is an acceptable exemption from the technical
requirements of Section III.G.2.f of Appendix R to 10 CFR Part 50.
In summary, the licensee has established that special circumstances
[[Page 3283]] are present. The exemption request satisfies the criteria
of 10 CFR 50.12(a)(2)(ii) as follows: The underlying purpose of the
rule is to ensure that safe shutdown can occur notwithstanding the
possibility of a fire. Application of the rule is not necessary to
achieve the underlying purpose because with respect to the possibility
of a fire affecting safe shutdown, (1) the fixed combustible loading in
containment is insignificant and the location of the sensing lines are
remote from the fixed combustibles that do exist; (2) automatic smoke
detectors are installed above each of the reactor coolant pumps; (3)
personnel access to the containment is restricted during power
operations, thus, the potential for transient combustible material to
accumulate is low; (4) the inherent fire retardant properties of the
power cables used in containment would minimize fire propagation; and,
(5) the effects of a fire inside containment are bounded by the worst
case loss-of-coolant accident analysis, thus safe shutdown would be
achievable.
IV
Accordingly, the Commission has determined, pursuant to 10 CFR
50.12, that (1) the Exemption as described in Section III is authorized
by law, will not endanger life or property, and is otherwise in the
public interest and (2) special circumstances exist pursuant to 10 CFR
50.12(a)(2)(ii). Therefore, the Commission hereby grants the following
Exemption:
(1) The Power Authority of the State of New York is exempt from the
requirement of 10 CFR Part 50, Appendix J, Section III.G.2.f, to the
extent that the redundant wide-range steam generator water level
sensing lines and the redundant pressurizer level sensing lines,
located inside containment, need not be separated by noncombustible
radiant energy shields.
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 (59 FR 11810).
This Exemption is effective upon issuance.
Dated at Rockville, Maryland, this 5th day of January 1995.
For the Nuclear Regulatory Commission.
Herbert N. Berkow,
Acting Director, Division of Reactor Projects--I/II, Office of Nuclear
Reactor Regulation.
[FR Doc. 95-923 Filed 1-12-95; 8:45 am]
BILLING CODE 7590-01-M