[Federal Register Volume 60, Number 141 (Monday, July 24, 1995)]
[Notices]
[Pages 37909-37911]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-18139]



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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-266 and 50-301]


Wisconsin Electric Power Co., (Point Beach Nuclear Plant, Units 1 
and 2); Exemption

I.

    Wisconsin Electric Power Company (WEPCO, the licensee) is the 
holder of Facility Operating License Nos. DPR-24 and DPR-27 which 
authorize operation of Point Beach Nuclear Plant (PBNP), Unit Nos. 1 
and 2. The units are pressurized water reactors (PWR) located in 
Manitowoc County, Wisconsin. The licenses provide, among other things, 
that the facilities are subject to all rules, regulations, and orders 
of the Nuclear Regulatory Commission (the Commission) now or hereafter 
in effect.

II

    Section III.G.1 of Appendix R to 10 CFR Part 50 requires, in part, 
that fire protection features shall be provided for structures, 
systems, and components important to safe shutdown and that one train 
of systems necessary to achieve and maintain hot shutdown conditions be 
free of fire damage.
    Section III.G.2 of Appendix R requires that (except as provided for 
in Section III.G.3), where cables or equipment (including associated 
nonsafety circuits that could prevent operation or cause maloperation 
due to hot shorts, open circuits, or shorts to ground) of redundant 
trains of systems necessary to achieve and maintain hot shutdown 
conditions are located within the same fire area outside of primary 
containment, certain specified means be provided to ensure that one of 
the redundant trains is free of fire damage.
    Pursuant to 10 CFR 50.12(a), the NRC may grant exemptions from the 
requirements of the regulations (1) which are authorized by law, will 
not present an undue risk to the public health and safety, and are 
consistent with the common defense and security; and (2) where special 
circumstances are present.
    By letter dated August 5, 1994, as supplemented by letters dated 
September 9, 1994, October 31, 1994, and February 28, 1995, the 
licensee requested an exemption from Section III.G.2.b of Appendix R to 
10 CFR Part 50, to the extent that it requires the separation of 
redundant trains of safe shutdown cables and equipment by a horizontal 
distance of more than 20 feet, with no intervening combustibles, in the 
auxiliary feedwater pump fire area. Intervening combustibles in the 
form of cable fill in three cable trays, added as part of the diesel 
generator addition project, are located within the separation space 
between redundant trains of cables and equipment required to achieve 
and maintain safe shutdown after a fire. In addition, the horizontal 
separation provided between redundant auxiliary feedwater pumps is only 
14 feet.
    The staff previously granted an exemption for intervening 
combustibles in this fire area in a Safety Evaluation dated July 3, 
1985. This evaluation stated that the minimum separation between 
redundant trains was 26 feet with a maximum separation of 60 feet. 
However, this space contains cable trays installed horizontal and 
parallel to the trays containing redundant cables. Based on the wide 
separation of the redundant trains, the configuration and limited 
amount of intervening combustibles, and the installed automatic Halon 
suppression system, the staff concluded that it is unlikely that an 
exposure fire or electrically initiated fire of the sufficient 
magnitude to prevent safe shutdown could develop prior to actuation of 
the Halon system and the arrival of the fire brigade. The three new 
cable trays (GW01-03, GN 01-03, and GC01-02), installed as part of the 
diesel generator addition project, are routed perpendicular to the 
redundant trains and provide a continuous path of combustibles between 
the redundant trains of equipment and cabling. This new configuration 
is outside the scope of the exemption granted to the licensee on July 
3, 1985.

[[Page 37910]]

    The auxiliary feedwater pump fire area contains the following safe 
shutdown equipment and cables: Two steam-driven and two motor-driven 
auxiliary feedwater pumps; local control panels for the motor-driven 
feedwater and service water pumps; power and control cables for the 
charging pumps; instrumentation equipment and cables; residual heat 
removal and component cooling water pump cables; and emergency AC power 
and DC control cables.
    One auxiliary feedwater pump and one service water pump are 
required to remain operable to achieve hot shutdown following a fire. 
The conduits containing power cables for one train of charging pumps 
for each unit in this area are enclosed in a fire barrier having a 
rating of one hour, in accordance with the requirements of Section 
III.G.2.c of Appendix R to 10 CFR Part 50. Instrumentation cables in 
trays and some conduits are separated by a minimum horizontal distance 
of 20 feet. This separation distance is not free of intervening 
combustibles. Instrumentation cables routed in conduit that are not 
separated by a horizontal distance of 20 feet have been enclosed in a 
fire barrier assembly having a rating of 1 hour, in accordance with the 
requirements of Section III.G.2.c of Appendix R to 10 CFR Part 50. The 
licensee has provided repair procedures and materials so that systems 
in this area necessary to achieve and maintain cold shutdown can be 
repaired within 72 hours, in accordance with the requirements of 
Section III.G.1.b of Appendix R to 10 CFR Part 50.
    The cables installed in the new trays meet the flame spread 
requirements specified in IEEE 383. To minimize the potential for fire 
propagation involving the new cable trays, the licensee has installed 
sheet metal tray covers on the top and bottom of each tray, installed a 
single layer of ceramic fiber blanket on top of the cables in each 
tray, and installed fire breaks at each end of each tray. In Generic 
Letter 86-10, ``Implementation of Fire Protection Requirements,'' the 
staff stated that cables routed in trays that are either fully open or 
fully closed should be considered as intervening combustibles. However, 
cables in trays having a solid sheet metal bottom, sides and top, if 
protected by automatic detection and suppression systems, have been 
found acceptable under the exemption process. The auxiliary feedwater 
pump fire area is provided with an automatic fire detection and alarm 
system that was designed in accordance with National Fire Protection 
Association (NFPA) 72D, ``Standard for the Installation, Maintenance, 
and Use of Proprietary Protective Signalling Systems,'' and NFPA 72E, 
``Standard on Automatic Fire Detectors.'' The Halon system installed in 
the area was designed in accordance with NFPA 12A, ``Halon 1301 Fire 
Extinguishing Systems.''
    To evaluate the fire hazard associated with this modification and 
the adequacy of the protection provided, the licensee contracted with 
Hartford Steam Boiler-Professional Loss Control to perform a fire 
protection engineering analysis. This analysis was submitted by 
licensee letter dated February 28, 1995. The analysis concluded that 
the new cable trays would not serve as an intervening combustible and, 
therefore, would not provide a path for fire propagation between 
redundant safe shutdown trains.
    Redundant equipment and cabling in the auxiliary feedwater pump 
fire area are separated by a horizontal distance ranging from a minimum 
of 14 feet, for the adjacent motor-driven auxiliary feedwater pumps, to 
31 feet for the local control panels. The separation between the steam-
driven auxiliary feedwater pumps is 29 feet. Each auxiliary feedwater 
pump is separated from the other pumps by concrete missile barrier 
walls that extend from the floor of the room to the ceiling.
    Combustibles located in this area consist of cable insulation on 
the approximately 184,000 feet of cable exposed in trays, approximately 
two gallons of lube oil located in the auxiliary feedwater pumps, and 
any transient combustibles that may be used or stored. Transient 
combustibles and hot work activities in this area are administratively 
controlled by plant procedures.
    Fire detection and suppression systems designed, installed and 
maintained in accordance with the requirements prescribed in the NFPA 
codes have been demonstrated to be effective in the early notification 
and suppression of fires at nuclear power facilities. Actuation of the 
automatic Halon fire extinguishing system, coupled with the rapid 
response of the plant fire brigade to the notification provided by the 
fire detection system installed in this area, gives reasonable 
assurance that fires in the auxiliary feedwater pump fire area will be 
promptly detected, controlled, and extinguished and, therefore, do not 
present a significant hazard to plant safety.
    Fire test conducted by the NRC, other government agencies, and the 
nuclear industry to evaluate the effectiveness of enclosing cable trays 
with sheet metal covers, or installing ceramic fiber blankets over 
cables in trays, have demonstrated that these methods, used 
independently or in combination, are effective in reducing the 
potential for ignition of, and flame spread along, cables installed in 
trays. The tests sponsored by the NRC were published in NUREG/CR-0381, 
SAND 78-1456, ``A Preliminary Report on Fire Protection Research 
Program Fire Barriers and Fire Retardant Coating Tests.'' Flame spread 
tests of the ceramic fiber blanket used in the auxiliary feedwater pump 
room (Carborundum Durablanket-S), in accordance with Underwriters 
Laboratories Test Standard 723, ``Test for Surface Burning 
Characteristics of Building Materials,'' demonstrate that this material 
has a flame spread rating of 0 and a smoke developed rating of 0. The 
use of IEEE 383 cables, the ceramic fiber blanket, and sheet metal 
cable tray covers provide reasonable assurance that a fire will not 
spread along the cables form one train of redundant safe shutdown 
equipment to the other.
    The plant configuration, administrative controls, and the fire 
protection provided for the auxiliary feedwater pump fire area provide 
reasonable assurance that at least one train of equipment and cabling 
required to achieve and maintain safe shutdown will remain operable 
following a fire in this area. This determination is based upon: (1) 
The code compliant automatic detection and suppression systems provided 
in the area; (2) the manual fire suppression capability provided in 
this area; (3) the sheet metal cable tray covers installed on the top 
and bottom of cable trays GN01-03, GW01-03 and GG01-04; (4) the ceramic 
fiber blanket installed on top of the cables in the new trays; (5) the 
use of IEEE 383 qualified cable in the new trays; (6) the spatial 
separation provided between redundant trains of equipment required for 
safe shutdown after a fire; and (7) the lack of sufficient combustibles 
in the vicinity of the new trays to present an exposure fire hazard.
    On the basis of this evaluation, the Commission concludes that the 
three cable trays installed as part of the diesel generator addition 
project do not present an undue risk to the public health and safety. 
Therefore, the licensee's request for an exemption from the technical 
requirements of Section III.G.2.b of Appendix R to 10 CFR Part 50, for 
the auxiliary feedwater pump fire area is acceptable.

III

    The Commission has determined, pursuant to 10 CFR Part 50.12, that 
this 

[[Page 37911]]
exemption as described in Section II above is authorized by law, will 
not present an undue risk to the public health and safety, and is 
consistent with the common defense and security. Furthermore, the 
Commission has determined that special circumstances as provided in 10 
CFR 50.12(a)(2)(ii) are present in that application of the regulation 
in the particular circumstances is not necessary to achieve the 
underlying purpose of the rule. The underlying purpose of Section 
III.G.1 of Appendix R is to ensure that one train of systems needed for 
hot shutdown be free of fire damage. Application of this section (to 
the extent that it requires the separation of redundant trains of safe 
shutdown cables and equipment by a horizontal distance of more than 20 
feet, with no intervening combustibles, in the auxiliary feedwater pump 
fire area) is not necessary to achieve the underlying purpose of the 
rule because the licensee's proposal still provides reasonable 
assurance that one safe shutdown train will be free of fire damage.

IV

    Accordingly, the Commission hereby grants an exemption from the 
requirements of Section III.G.2.b of Appendix R to 10 CFR Part 50 to 
allow the intervening combustibles in the form of cable fill in three 
cable trays to remain installed in the auxiliary feedwater pump fire 
area. These trays were added as part of the diesel generator addition 
project, and are located within the separation space between redundant 
trains of cables and equipment required to achieve and maintain safe 
shutdown after a fire.
    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 (60 FR 35755).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland this 18th day of July 1995.

    For the Nuclear Regulatory Commission.
Jack W. Roe,
Director, Division of Reactor Projects III/IV, Office of Nuclear 
Reactor Regulation.
[FR Doc. 95-18139 Filed 7-21-95; 8:45 am]
BILLING CODE 7590-01-M