ML20072R968
| ML20072R968 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/22/1983 |
| From: | Purple R Office of Nuclear Reactor Regulation |
| To: | ARKANSAS POWER & LIGHT CO. |
| Shared Package | |
| ML20072R945 | List: |
| References | |
| NUDOCS 8304060518 | |
| Download: ML20072R968 (16) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COM4!SSION In the Matter of
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ARKANSAS POWER & LIGHT COMPANY Docket No. 50-368 (Arkansas Nuclear One, Unit No. 2)
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EXEMPTION I.
Arkansas Power and Light Company (AP&L or the licensee) is the holder of Facility Operating License No. NPF-6, which authorizes the operation of Arkansas Nuclear One, Unit 2 (the facility). The facility consists of a pressurized water reactor-(PWP,), located at.the licensee's' site in Russellville, Arkansas.
The license is subject to all ru'les and regulations of the Nuclear Regulatory Commission (the Commission).
II.
10 CFR 50.48, " Fire Protection", and Appendix R to 10 CFR Part 50,
" Fire Protection Program for Nuclea[r Power Facilities Operating Prior to January 1,1979" set forth certain specific fire protection features required to satisfy the General Design Criterion related to fire protection (Criterion 3, Appendix A to 10 CFR 50).
Section III.G of Appendix R requires fire protection for equipment important to safe shutd'own. Such fire protection is achieved by various combinations of fire barriers, fire suppression systems, fire. detectors, and separation of safety trains (III.G.2) or alternative safe shutdown equipment free of the fire area (III.G.3). The objective of this protection 8304060518 830322 PDR ADOCK 05000
is to assure that one train of' equipment needed for hot shutdown would be undamaged by fire, and that systems needed for cold shutdown could -
be repaired ~ within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (III.G.1). '
III.
By letter dated July 1,1982, the licensee requested exemptions from the technical requirements of Section III.G of Appendix R to 10 CFR 50 for various areas in Unit 2.
By letter dated November 11, 1982, the licensee provided new proposals and additional clarifying information regarding the previous exemption requests. As a result of these letters, the requested exemptions involving Section III.G are as follows:
~III.G.2 Intake Structure, Below El. 354' Intake Structure, E1. 354' Intake Structure, E1. 366' Yard Area Manholes 2MH01E, 2MH02E, 2MH03E General Access Area, E1. 317', Fire Zone 2006LL East-Pump Area, El. 317', Fire Zone 2007LL Pump Room, Fire Zone 2024JJ Containment Building, Fire Zones 2032K and 2033K Tank Rooms, Pump Rooms and Corridors, E1. 355' Fire Zone 2040JJ Lower South Piping Penetration Area, Fire Zone 2055JJ Corridor, E1. 372',. Fire Zone 2109U III.G.3 Upper North Piping P.enetration Area, Fire Zone 2081HH Motor Control Center, Fire Zone 2096?1 Electrical Equipment Room. E1. 368', Fire Zone 2091BB l
Corridor Area, Fire Zone 2107N Pipeway and Equipment Access Way, Fire Zone 2223KK l
Pump Room, Fire Zone 2106R Core Protection Calculator Panel, Fire Zone 2150C Health Physics Area, Fire Zone 2136I The acce'ptability of these requests is addressed below'. More details are contained in the NRC staff's related Safety Evaluation (SE) dated !! arch 22, 1983, which is included herein by reference.
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.s IV.
Intake Structure, Below E1. 354' The licensee requested exemption from Section III.G.2 to the extent it requires an automatic fire suppression system. This area contains circulating water piping, associated valves and power cables.
This zone consists of the service water pump intake bays; therefore the water level in the intake bays precludes the possible accumulation of transient combus.tible materials as anticipated in other plant areas.
Because the likelihood of an exposure fire is low, these alternative features compensate for the required suppression system and provide a level of fir.e protection equ.ivalent to that required by
- Section III.G. of Appendix R.
Therefore, the exemption is granted.
Intake Structure, El. 354'
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The licensee requested exemption from Section III.G.2 to the extent it requir&s an automatic fire suppression system. This area contains redundant cabi'es in conduits for'the' service water pumps and
, discharge valves. The licensee will reroute all cables required for the service water pump motors to provide greater than 20 feet of separation, and will enclose one train of pump power cabling in a one-hour rate' fire barrier.
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The in-situ combustible loading 'at this elevation consists primarily of cable insulation. This fire area is provided with portable fire extinguishers, manual hose stations and a smoke detection system.
In the event of an exposure fire involving transient combustible 4
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-4 materials, there will _be a time lag between the ignition of the fire, detection and alarm, and the fire brigade response. The proposed configuration of cables and one-hour rated fire barrier wil'1 provide protection against the thermal flux of an exposure fire for a sufficient period.of time to enable the fire brigade to respond and extinguish a fire prior to damage of both trains.
The level of existing protection, in conjunction with the modifications in the Intake Structure, El. 354', provides a level of fire protection equivalent to the technical requirements of-SectionIII.G.ofAppend[xR. Therefore, the exemption is granted.
Intake Structure, E1. 356' The licensee requested exemption from Se~ction III.G 2 to the extent it requires separation of cables and equipment and associated non-safety, circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustible or fire hazards, and also to the extent it requires full coverage of an automatic fire suppression system. This area contains the A and B trains and swing service water pump motors, associated valves and cables and the ventilation equipment for the intake structure. Redundant trains of safe shutdown equipment are separated by less than 20 feet. Missile
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barriers provided between each pump also act as radiant energy shields.
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The in-situ combustibles at this level consist of one non-safety,.
related cable tray and approximately 131/2 gallons of lubricating oil in each service water pump motor. Floor drains are provided in the vicinity of each pump to collect and drain any potential lube oil leaks.
Portable fire extinguishers, manual hese reels, and an ionization-type smoke detection system are provided throughout the area. The licensee q
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. will install an automati'c sprinkler system for the protection of the three se'rvice water pump motors.
Due to the low in-situ combustible loading in the intake structure, the partial width missile barriers in c'onjunction with the automatic sprinkler system will provide adequate assurance that one train of service wcter pumps will be maintained free of fire damage. The r'esulting fire protection for the Intake Structure, 4
E1. 366' provides a level of protection equivalent to the technical requirements of Section III.G. of Appendix R.
Therefore, the exemption is granted.
4 Yard Area Manholes, 2tN01E, 2MH02E, and 2f1H03E The licensee requested exemption from Section III.G.2 to the extent this section requires: 1)'sepaiation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal
. distance of more than 20 feet with no intervening combustible or fire hazards, 2) enclosure of cable and equipment and associated non-safety circuits of one redundant train in a fire barrier having a one-hour rating, 3) fire dete.ctors, and 4) automatic fire suppression system installed in the fire area.
These fire areas consist of three manholes which are concrete bunkers approximately 7 feet by 7 feet by 8 feet, and ar'e located i
remote from the remainder of the plant. The power cables for redundant
_ trains of service water pumps are located in ciose pedximity insiae the manholes. The manholes are not ventilated and can be'accdssed
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l only by lifting the concrete natches 'with a crane. The licensee will fill the manholes with a non-combustible material such as sand or vermiculite.
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Filling the manholes with sand or vermiculite will prevent a fire from occurring in the manholes and, therefore, an adequate ievel of fire protection will be provided equivalent to"Section III.G, of
~ Appendix R.
Therefore, the exemption is granted.
General Access Area, E1. 317', Fire Zone 2006LL and East Ptsnp Area, El. 317', Fire Zone 2007LL
'By letter dated November 11, 1982, the licensee committed to install automatic fire suppression in these areas, thereby complying with Section III.G. The exemption requests were, therefore, withdrawn.
Pump' Room, Fire Zone.2024JJ The licensee requested an exemption from Section III.G.2 to the extent this section requires separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a three-hour rating.
This fire area contains the steam turbine driven emergency feedwater pump. The boundar'y walls, floor, and ceiling assemblies are reinforced concrete with a three-hour rating.
Penetrations through these walls will be upgraded to a three-hour rating, with the exception of the door to the room. Because of other safety requirements, this door is required to be a one inch thick watertig'ht door, and is consequently non-fire-rated. The redundant motor-driven feedwater pump is located in an adjacent room of similar construction, with the same type of watertight access door..
The in-situ combustible loading in the steam-turbine driven pump 2
room is approximately 2200 BTU /FT, which, if totally consumed, would produce an equivalent fire severity on the ASTM E-119 standard time-4 temperature curve of less than two minutes. The in-situ combustible 6
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loading in the redundant motor-driven pump room _is approximately 2 hich, if totally consumed, would produce an equivalent 3100 BTU /FT w
fire severity on the ASTM E-119 standard time-temperature curve of less than three minutes. A smoke detection sys' tem is provided in the area. Portable fire extinguisherst and manual hose stations are readily accessible in adjacent areas.
The licensee has provided a three-hour rated fire barrier for the
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separation of redundant trains of emergency feedwater pumps. The watertight access door installed in this fire barrier is not an approved three-hour rated fire. door, and therefore, could permit the spread of fire in less than three hours.
The combustible loading in this area is substantially lower than needed for a fire of three-hours duration. An exposure fire would therefore be of limited severity and duration. The design of the water-tight door provides, a degree of inherent fire protection.
It is our experience -that typical watertight doors provide equivalent protection as three-hour rated fire doors.
This combination of features provides reasonable assurance that a fire in this area will be detected and extinguished before the redundant emergency feedwater, pump is damaged. Thus, the level of existing protectio.n for this area provides a level of fire protection equivalent to the technical requirements of Section III.G of Appendix R.
Therefore, the exemption is granted.
Containment Building, Fire Zones 2032X and 2033K Thb licensee requested exemption from Section III.G.2 to the extent it requires separation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal distance,of more
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n-than 20. feet with no, intervening combustible or fire hazards.
The containment building has been subdivided into two fire areas.
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There is no fire barrier between the two fire arear. The separation of
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cables and equipment within each fire area is such that only one division of equipment is located in each fire area. With the exception of the Reactor Coolant System (RCS) pressure instrumentation, the n$1nimum separation distance between redundant equipm'ent in the containment building is greater than 30 feet, however there are several non-safety related cable trays which pass from one fire area to the other. The i
licensee has provided fire stops in t'he cable trays to prevent the spread of flames along the cables.
The fire area in the north half of the containment building contains two shutdown cooling drop line (RHR letdown) valves, in series.
Spurious operation of both valves could cause a loss of reactor coolant.
The spurious signal required for this action would have to be a short, phase to phase, in'a specific manner involving the power cables, which are routed in close proximity in this area.
The fire area in the south half of the containment building contains all four channels for RCS pressure indication. A junction box.for
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each channel is situated outside the secondary shield wall near the pressurizer. The Channel 1 and Channel. 4 junction boxes are separated by 17 feet.
Due to the angular shape of the wall in this A,rea, each
, unction box is partially' shielded from a fire involving the other j
- by a corner of the concrete barrier.
From the junction boxes, the conduits for the pressure indicators are embedded in concrete and routed to the cable penetration area.
Both areas are protected by a partial coverage smoke detection system.
Manual hose stations and an oil collection system for the reactor coolant pumps are provided.
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3 Due to the restrheted access to this area, the probability of an exposure fire from the accumulation of transient combustibles and which' could potentially bypass the cable tray fire stops is unlikely.
Therefore, the fire stops installed in the intervening cable trays will provide reasonable assurance that one train will be maintained. free of fire damage. Because the amount of in-situ combustibles is low in this area and early warning detection,provided, a fire in this area which could damage both RHR letdown power cable conduits is unlikely.
Further, it is unlikely th'at fire damage would occur in the specific manner required. This combination of conditions provides reasonable assurance that a spurious operation of both valves is not likely to e
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occur. The RCS pressure instrumentation is separated by 17 feet. A concrete missile barrier provides a partial radiant energy shield between the redundant instrumentation channels. Because of the unlikely nature of significant fire occurrence inside containment'and the mitigating effects of the intervening missile barrier, there is reasonable assurance that one train will be maintained free of fire damage.
The level of protection inside containment provides a level of fire protection equivalent to the technical requirements of Section III.G of Appendix R.
Therefore, the exemption is granted..
Tank Rooms, Pump Rooms, and Corridors, El.J55', Fire Zone 2040JJ The licensee has requested exemption from Section III.G.2 to the 4
extent it requires an automatic fire suppression system. This area contains several pump and tank rooms and adjacent corridors. The
. redundant equipment in this area consists of the three charging pumps and associated cables.
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Walls, floors, and ceiling assemblies are reinfo'rced concrete.
The ceiling height in* the area is 17 feet. The charging pumps are "
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separated by less than 20 feet and are in cubicles approximately 10 feet by 16 feet. The pump cubicles are separated by partial height j
concrete walls, eight feet.high. The combustible loading in this area consists of 10 gallons of lubricating oil for each pump and several cable trays in an adjacent corriddr. A cable tray.is a' iso located in two of the. three pump cubicles. The combustible loading added by the cable trays has not been quantified by the licensee, but is described as " moderately loaded with a fill of approximately 20%."
The cables are open cable trays and are routed 8 to 12 feet above the floon. Cables for the A and C trains are ' separated by
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approximately 10 feet, and cables for bie B and C trains are separated by approximately 12 feet. At least one pump is required for safe shutdown.
The licensee will modify the fire protection in this area by-enclosing the cables for two of the three charging pumps in a one-hour barrier and enclosing one train of the corridor area cable trays in
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a one-hour barrier for a sufficient length to permit 20 feet of horizontal separation between unprotected redund. ant cables. The configuration of cables in this area involves redundant cable trays in two corridors, perpendicular to each other. In addition to the 20 feet of separation provided by the proposed barrier, the corner of the concrete wall at the intersection provides.a line-of-sight radiant energy shield between' redundant cables. This area is provided with smoke de'tectors, portable extinguishers and manual fire hose stations.
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Because of the low in-situ combustible loading in this area, intended installation of one-hour barriers and intervening walls, and the detection system, in the event of an exposure fire, redundant cables will be protected for a sufficient period to enable the fire brigade toiespond and extinguish a fire prior to damage of both trains. The protection in the charging pump area in conjunction with the proposed one-hour barriers provides a level of fire protection equivalent to Section III.G. Therefore~, the exemption is granted.
Lower South Piping Penetration Area, Fire Zone 2055JJ The licensee has.' requested exemption from III.G.2 to the e.xtent it requires separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a three-hour' rating. The piping penetration area is adjacent to the charging pump area. The fire area boundary wall separating the two areas is a concrete wall, but does not carry a fire resistance rating. The
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licensee notes that this wall was previously accepted, based on the low combustible loadin'g in' the area. The wall currently contains various penetrations and an open doorway. The A-train charging oumo cable tray is located in the piping penetration area approximately 17 feet from _ the open doorway while the C-train cable tray is located 2
in the adjacent area approximately 24 feet from-the doorway. The B-train cable tray is also in this area.
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.e The combustible loading in the piping penetration area. consists.
of three open ' cable trays.
The quantity of combustible cable insulation has not been provided, but is described as " moderate".
Smoke detection, portable extinguishers and manual hose stations are provided in both areas.
The licensee will modify the fire protection in these areas by upgrading all. penetrations through the boundary wall to provide a three-hour rating, with 41e exception of the doomay.
For the protection of the doomay, the licensee notes that there are two doors which must be opened for passage between these areas.
The first door is a fully louvered, hollow metal door. This door is equipped with a surface type intrusion alarm switch.
The second door is an air tight door, which will be replaced with a three-hour l
rated fire door equipped with a latch to enable this door to open at an overpressure-of 0.25 psig in order to limit peak pressure.in that zone. This pressure is not expected to be reached by fire-caused pressures..
In this. area, an open doorway would' violate the three-flour l
barrier and would provide direct comunication between two fire 1
areas containing redundant trainsaf safe shutdown related cabis.
The three-hour rated fire door with special latch' for overpressure release which will be installed, is adequate for the fire hazard in these areas. The protection provided for the piping penetration area provides a level of fire protection equivalent to the technical requirements of Section III.G of Appendix R.
Therefore, the exemption is granted.
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Corridor, El. 372', Fire Zone 21090 The licensee has requested exenption from Sect' ion III.G.2 to the extent it requires separation of cables and equipment and ass'ociated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustible or fire hazards, or enclosure of cables and equipment and associated non-safety circuits of one redundant train in a fire barrier having one-hour rating.
This corridor area is approximately 86 feet by 12 feet with a 12-foot ceiling.
The floor, walls and ceiling assentlies are reinforced concrete with a three-hour ~ rating. The fim area includes an access corridor to one of the diesel generator rooms.
The redundant cables and equipment in this area are the electrical distribution panels 2RS3 and 2RS4 and associated cables.
This equipment provides the power supply for safe shutdown instrumentation.
The two redundant distribution panels are wall mounted and separated by approximately 18 feet.
Intervening combustibles between.the panels include several ceiling level cable trays containing what the licensee describes as,.
"a large ' amount of cable insulation in open cable trays".'
Various transient combustibles could be introduced in this area 'during maintenance periods, including 55 gallon drums of lubricating. oil.
The licensee will modify the fire protection in this area by enclosing the conduits associated with one of the distribution panels in a one-hour rated fire barrier and coating all intervening cables between the panels.
with r flame retardant coating. A smoke detection system is provided throughout the corridor in addition to line-type heat detectors in each cable tray. An automatic, open head sprinkler system, portable fire extinguishers and manual fire hose stations are also installed in the area.
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The early warning detection system and automatic water deluge
, system will ensure.that any, fires are promptly detected and suppressed.
The intervening combustibles between the redundant panels are located above the panels at the ceiling level. The coating of all intervening cab.les with a flame retardant coating, which is not equivalent to a one-hour barrier, but which will retard the propagation of flame, and
' enclosing one train of conduits for the distribution panels, which rise vertically to the ceiling level, in a one-hour fire rated barrier will provide enhanced protection for the distribution panels and will reduce the probability of damage to both trains prior to activation of the corridor detection and suppression system. The intended modifications in conjunction with the existing detection and automatic deluge system will provide an alternative protection system that gives reasonable assurance that one train of distribution panels will be maintained free of fire damage.
l The existing protection for this area in conjunction with tie" proposed one-hour fire rated barrier and flame retardant coating of intervening cable trays provides a level of fire protection equivalent to the technical requirements of Section III.G of Appendix R.
Therefore, the exemption is granted.
Fixed Fire Suppression for Eight Areas The licensee has provided alternate shutdown capability for the following areas in Unit 2:
a)
Upper North Piping Penetration Area, Fire Zone 2081HH b) Motor Control Center, Fire Zone 2096M c)
Electrical Equipment Room, El. 368', Fire Zone 2091B8 1
d) Corridor Area, Fire Zone 2107N i.
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e) Pipeway & Equipment Access Way, Fire Zone 2223KK f)' Pump R.oom, Fire Zone 2106R g) Core Protection Calculator Panel, Fire Zone 2150C h) Health Physics Area, Fire Zone 2136I The combustible loading in these zones is negligible.
The redundant equipment in _these areas is primarily one system', the
' diesel fuel transfer pumps. The licens e requests an exer 6ption from providing fixed extinguishing systems in these areas and detection for
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Fire Zones 20_81HH and 2136I as required by Section III.G.3.
All of the above fire zones represent a similar configuration, i.e., combustible loading is light, there is alternate shutdown capability, and manual fire suppression equipment is available. The
' low combustible loading in these areas ensures that safety related equipment in adjacent areas will not be threatened. The installation of a fixed fire suppression system in all these areas and detection ~for Fire Zones 208111H and 21361 will not significantly increase the level e
of fire protection in these areas.
The existing fire protection in conjunction with alternate shutdown
. capability in the above areas provides a level of fire protection equivalent to the technical requirements of Section III.G.3 of Appendix R.
.Therefore, the exemptions are granted.
V.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, the exemptions requested by the licensee's letters as referenced 4
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7590-01 and discussed in III, and IV. above are authorized by l'aw, will not
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endanger life o'r property or the common defense and security, are otherwise in the public interest, and are hereby granted".
The Commission has determined that the granting of these exemptions will not result in any significant environmental impact and that pursuant to 10 CFR 51.5(d)(4) an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with this action.
A copy of the Safety Evaluation dated March 22, 1983 related to this action is available for public inspection at the Connission's Public Document Room,1717 H Street, fl. W., Washington, D. C. 20555 and at the Tomlinson Library, Arkansas Tech University, Russellville, Arkansas 72001. A copy may be obtained upon request addressed to the U. S. fluclear Regulatory Commission, Washington, D. C.
20555, Attention:
Director, Division of Licensing.
This Exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMMISSI0fl
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Robert A. Purple, De.puty Director Division of Licensing Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland this 22nd* ddy of March 1983.
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