[Federal Register Volume 64, Number 80 (Tuesday, April 27, 1999)]
[Notices]
[Pages 22655-22657]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-10489]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-289]
GPU Nuclear, Inc. et al. (Three Mile Island Nuclear Generating
Station, Unit 1); Exemption
I
GPU Nuclear, Inc., et al. (GPUN or the licensee) is the holder of
Facility Operating License No. DPR-50, which authorizes operation of
the Three Mile Island Nuclear Generating Station, Unit 1 (TMI-1 or the
facility) at power levels not to exceed 2568 megawatts thermal. The
facility consists of one pressurized-water reactor located at the
licensee's site in Dauphin County, Pennsylvania, and was licensed to
operate on April 19, 1974. 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.
II
Appendix R to 10 CFR part 50 contains specific requirements
regarding fire protection features of nuclear power plants operating
prior to January 1, 1979. Subsection III.G.2.c of Appendix R specifies,
in part, the enclosure of cable and equipment and associated non-
safety-related circuits of one redundant train in a fire barrier having
a 1-hour rating. The underlying purpose of Subsection III.G.2.c of
Appendix R is to provide reasonable assurance that one safe shutdown
train and associated circuits used to achieve and maintain safe
shutdown are free of fire damage. By letter dated December 31, 1996, as
supplemented by letters dated September 8, 1997, December 30, 1997, May
21, 1998, October 14, 1998, November 25, 1998, and December 23, 1998,
the licensee requested an exemption from the requirements of section
III.G.2.c of Appendix R to the extent that they require the enclosure
of one train of redundant safe-shutdown circuits in 1-hour fire-rated
barriers. The licensee is requesting this exemption in accordance with
the provisions of 10 CFR 50.12.
The licensee's request encompasses 10 fire zones/areas that have
Thermo-Lag installed on electrical raceways for the original purpose of
providing a 1-hour rated barrier separating redundant circuits located
in the same fire area in accordance with section III.G.2.c of Appendix
R. In its December 31, 1996, letter, the licensee provided information
indicating that the Thermo-Lag envelopes in the zones/areas for which
exemptions are requested, have fire endurance ratings of less than 1
hour. The exemption was requested for fire zones/areas AB-FZ-3, AB-FZ-
4, AB-FZ-5, AB-FZ-7, CB-FA-1, FH-FZ-1, FH-FZ-2, FH-FZ-6, ISPH-FZ-1, and
ISPH-FZ-2. In its submittal, the licensee states that modification of
the identified fire barriers to achieve a 1-hour fire rating in
accordance with American Society for Testing and Materials Standard E-
119 (ASTM E-119) would cost approximately $1.0 million, which
represents a substantial expenditure for minimal safety enhancement.
The staff holds to a defense-in-depth philosophy when determining
adequate fire protection. In areas in which fire barriers are required
to be rated at 1 hour, barriers that have actual fire endurance ratings
of less than 1 hour are acceptable only if the fire area/zone also has
automatic detection and fire suppression systems provided in accordance
with applicable National Fire Protection Association (NFPA) standards
and when the fire hazard to the Thermo-Lag-protected envelope is
minimal. The combination of these features and conditions provides
defense in depth.
The fire areas/zones that are the subject of this exemption request
do not currently meet the technical requirements of section III.G.2.c
of Appendix R because the Thermo-Lag electrical raceway fire barrier
envelopes for the fire zones discussed above are not rated at 1 hour in
accordance with the rating requirements of NRC Generic Letter 86-10,
Supplement 1. Section III.G.2.c of Appendix R could only be satisfied
by protecting each envelope with a 1-hour fire-rated barrier. The fire
zones reviewed do not have any Thermo-Lag envelopes rated at 1 hour or
more; therefore, the criteria for granting an exemption, for the most
part, are based on the availability of automatic detection and
suppression systems and the fire hazards present in each fire zone.
III
The staff has completed its evaluation of the licensee's request
for an exemption. The licensee has administrative controls in place
over transient combustibles and work in the plant in accordance with 10
CFR part 50, Appendix R, section III.K, Items 1-8, as documented in an
NRC safety evaluation dated June 4, 1984. These controls require total
in situ plus allowable transient fire load in a fire area/zone (or
cumulative load) to be half of what would challenge the lowest rated
barrier in the zone based on equivalent fire severity. These limits are
documented in licensee procedures that are referenced in and implement
the licensee's Fire Protection Program under License Condition 2.c(4).
On December 31, 1996, the licensee submitted an evaluation of all
Thermo-Lag Fire barriers that are the subject of this exemption request
in Topical Report #094, Revision 2, ``TMI 1 Evaluation of Thermo-Lag
Fire Barriers,'' dated December 20, 1996. The licensee found that most
of the barriers currently have a fire rating of less than 1 hour (when
tested in accordance with the ASTM E-119). In each of the areas/zones
that have automatic suppression and/or automatic detection features,
the systems installed in the plant meet all applicable NFPA codes,
specifically the criteria for a Class 1 detection system specified in
NFPA 72D and NFPA 13 or NFPA 15 for suppression systems.
Fire zones AB-FZ-4 and FH-FZ-1 contain both automatic suppression
and detection features. Fires in these zones are postulated to be
slowly developing cable fires, with possible ignition sources including
cable overload or transient combustibles. If a fire were to occur in
these fire zones, indication of the fire would be received in the
control room, through the ionization smoke detection system, and either
the automatic pre-action system (AB-FZ-4) or the wet pipe sprinkler
system (FH-FZ-1) would initiate suppression if the fire continued to
grow. If necessary, the fire brigade would be dispatched soon
thereafter. The licensee estimates that the fire brigade will respond
to these fire zones 15 minutes after receiving an alarm. Manual fire
fighting equipment (hand-held fire extinguishers and hose stations) is
available in or adjacent to these fire zones.
Fire area CB-FA-1 contains both automatic suppression and detection
capability. A fire in this area is postulated to be a slowly developing
cable fire, with possible ignition sources being overload or transient
combustibles. Exposure of the protected envelope to fire is possible
through ignition of cable insulation. There is also an acetylene gas
line running above the suspended ceiling from an external tank. The
licensee committed in its October 14, 1998, and December 23, 1998,
letters to install detectors for
[[Page 22656]]
combustible gas in this area to provide prompt detection and
notification of an acetylene leak, so that the leak could be promptly
isolated at the source prior to reaching the lower explosive threshold
for acetylene gas. If a fire were to occur in this fire area,
indication of the fire would be received in the control room, through
the ionization smoke detection system which is above the suspended
ceiling. An automatic wet-pipe sprinkler system which is below the
suspended ceiling would actuate to suppress the fire should it continue
to develop. If necessary, the fire brigade would be dispatched soon
thereafter, and response has been estimated by the licensee to be 15
minutes. A hand-held dry chemical extinguisher is also available
adjacent to this fire area.
Fire zone FH-FZ-6 is provided with automatic detection and will be
provided with automatic suppression. The licensee committed to install
an automatic wet-pipe sprinkler suppression system in this fire zone in
its letter dated December 23, 1998. A fire in this zone is postulated
to be a slowly developing cable fire, with possible ignition sources
being transient combustibles. If a fire were to occur in this fire
zone, indication of the fire would be received in the control room by
the ionization smoke detection system or through the actuation of the
wet-pipe sprinkler system to be installed. If necessary, the fire
brigade would be dispatched soon thereafter, and the licensee estimates
a brigade response would occur within 15 minutes. Manual fire
suppression capability (hose stations and dry chemical extinguisher) is
available in or adjacent to this fire zone.
Fire zone ISPH-FZ-1 contains both automatic detection and
suppression features. A fire in this zone is postulated to be a slowly
developing cable fire, with electrical switchgear as a possible
ignition source. If a fire were to occur in this zone, indication of
the fire would be received in the control room by the ionization smoke
detector system. A zone-wide automatic wet-pipe sprinkler system is
available to suppress the fire, should it develop, and portable
extinguishers (carbon dioxide and dry chemical) are available within
the fire zone. The fire brigade would be dispatched, if necessary, and
the licensee estimates a brigade response time of 25 minutes. A
portable extinguisher and yard hydrant are located outside the fire
area and are available to fight fires in this fire zone. Protected
envelopes consisting of cables and conduits passing through this fire
zone are fire rated at 39 and 50 minutes respectively, and pass within
the vicinity of in-situ combustibles in only limited instances.
Fire zone ISPH-FZ-2 contains both automatic detection and
suppression features. A fire in this zone is postulated to be a slowly
developing cable fire, with electrical switchgear as a possible
ignition source. If a fire were to occur in this zone, indication of
the fire would be received in the control room by the ionization smoke
detector system. A zone-wide automatic wet-pipe sprinkler system is
available to suppress the fire, should it develop, and a portable
extinguisher (carbon dioxide) is available within the fire zone. The
fire brigade would be dispatched, if necessary, and the licensee
estimates a brigade response time of 25 minutes. A portable
extinguisher and yard hydrant are located outside the fire area and are
available to fight fires in this fire zone. Protected envelopes
consisting of cables and conduits passing through this fire zone are
fire rated at 39 and 50 minutes, respectively, and pass within the
vicinity of in-situ combustibles in only limited instances.
The staff is relying on the licensee's commitments made in its
October 14, 1998, and December 23, 1998, letters for approval of the
exemptions for fire area CB-FA-1 and fire zone FH-FZ-6. Therefore,
approval of an exemption for that fire area and zone is contingent upon
the licensee completing the modifications described in those
submittals. The staff believes that reasonable assurance exists that an
adequate level of fire safety has been provided through the
availability of automatic suppression and detection in these fire
zones/areas to ensure that one division of safe-shutdown components
necessary to achieve safe shutdown will remain free of fire damage.
Therefore, the underlying purpose of the rule is satisfied and this
request for exemption with respect to the foregoing fire areas/zones
from the requirements of 10 CFR part 50, Appendix R, section III.G.2.c
meets the special circumstances delineated in 10 CFR 50.12(a)(2)(ii) in
that the application of the regulation in these particular
circumstances is not necessary to achieve the underlying purpose of the
rule. While the installed Thermo-Lag barriers in the fire zones
demonstrate less than a 1-hour fire endurance rating, they do provide
measured resistance to fire. The areas in which the Thermo-Lag
envelopes are located have a low combustible loading in the area of the
protected envelopes, have available manual suppression capability, and
are equipped with automatic suppression and detection features; the
combination of these features and circumstances reflect a level of
safety that meets the underlying purpose of the rule. Therefore, the
staff believes that the exemption should be granted for fire zones/
areas AB-FZ-4, FH-FZ-1, CB-FA-1, FH-FZ-6, ISPH-FZ-1, and ISPH-FZ-2.
The staff does not believe the same assurance has been provided for
fire zones AB-FZ-3, AB-FZ-5, AB-FZ-7, and FH-FZ-2. Fire zones AB-FZ-3,
AB-FZ-5, and AB-FZ-7, have automatic detection but not suppression.
Fire zone FH-FZ-2 has automatic suppression but not detection.
The licensee has failed to provide reasonable assurance that one
division of safe-shutdown components necessary to achieve safe shutdown
will remain free of fire damage in the four zones immediately discussed
above. Accordingly, as discussed above and in the staff's Safety
Evaluation dated April 20, 1999, the staff has concluded that the
licensee's request for an exemption from the technical requirements of
section III.G.2.c of Appendix R should be denied for fire zones AB-FZ-
3, AB-FZ-5, AB-FZ-7, and FH-FZ-2.
IV
Pursuant to 10 CFR 50.12(a)(2), the Commission will not consider
granting an exemption from the requirements of a regulation unless
special circumstances are present. Subsection (ii) of 10 CFR
50.12(a)(2) includes as special circumstances situations where
application of the subject regulation would not serve the underlying
purpose of the rule or is not necessary to achieve the underlying
purpose of the rule.
The underlying purpose of section III.G of Appendix R is to provide
reasonable assurance that one safe shutdown train and associated
circuits used to achieve and maintain safe shutdown are free of fire
damage. As stated above, the staff has determined that the underlying
purpose of the rule has been satisfied with respect to fire zones AB-
FZ-4, FH-FZ-1, CB-FA-1, FH-FZ-6, ISPH-FZ-1 and ISPH-F2-2. Accordingly,
the Commission has determined that, pursuant to 10 CFR 50.12(a)(2)(ii)
special circumstances are present in connection with these fire zone/
areas.
The Commission has also determined that, pursuant to 10 CFR 50.12,
the exemption requested by the licensee for fire zones/areas AB-FZ-4,
FH-FZ-1, CB-FA-1, FH-FZ-6, ISPH-FZ-1, and ISPH-FZ-2 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 GPU Nuclear, Inc., an
exemption
[[Page 22657]]
from the technical requirements of section III.G.2.c of Appendix R to
10 CFR part 50, to the extent that it requires the enclosure of certain
redundant safe-shutdown circuits in 1-hour fire-rated barriers, for
fire zones/areas AB-FZ-4, FH-FZ-1, CB-FA-1, FH-FZ-6, ISPH-FZ-1, and
ISPH-FZ-2 at TMI-1. The exemption for fire area CB-FA-1 and fire zone
FH-FZ-6 is contingent upon the licensee completing the commitments
identified in its letters of October 14, 1998, and December 23, 1998,
for that fire area and zone. The request for exemption for fire zones
AB-FZ-3, AB-FZ-5, AB-FZ-7, and FH-FZ-2 is denied.
Pursuant to 10 CFR 51.32, the Commission has determined that the
issuance of this exemption will have no significant impact on the
quality of the human environment (64 FR 19205).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 20th day of April 1999.
For the Nuclear Regulatory Commission.
John A. Zwolinski,
Director, Division of Licensing Project Management, Office of Nuclear
Reactor Regulation.
[FR Doc. 99-10489 Filed 4-26-99; 8:45 am]
BILLING CODE 7590-01-P
