ML20072R942
| ML20072R942 | |
| 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 8304060505 | |
| Download: ML20072R942 (13) | |
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UNITED STATES OF AMERICA NUCLEAR REGUL TORY COMMISSION
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In the Matter of
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ARKANSAS POWER & LIGHT COMPANY
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Docket No. 50-313
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(Arkansas Nuclear One, Unit No. 1)
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EXEMPTION
'I.
Arkansas Power and Light Company (AP&L or the licensee) is the holder of Facility Operating License No. DPR-51, which authorizes the' operation of Arkansas Nuclear One, Unit 1 (the facility). The facility consists of a pressurized water reactor (PWR), located at the licensee's site in Russellville, Arkansas.
The license is subject to all rules and regulations of the Nuclear Regulatory Commission (the Commission).
f II.
10 CFR 50.48, " Fire Protection", and hppendix R to 10 CFR Part 50,
" Fire Protection Program for Nuclear Power Facilities Operating Prior fo January 1,1979" set forth certain specific fir.e' 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 shutdown. 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 8304060505 830322 PDR ADOCK 05000313 F
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. protection is to assure that one train of equipment needed for hot
. shutdown would be undamaged by fire, and that systems need'ed for cold shutdown could b,e 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 1.
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, El. 354' Intake. Structure, El. 366' Yard Area Manholes, IMH04 and IMH06 Radwaste Processing Area, Waste Monitor Tan'k Room, Fire Zone 20Y Radwaste Processing Area, Make-up Pump Rooms and Adjacent Corridor, Fire Zone 20Y Containment Building, Fire Zones 32X and 33K Pipe Area, Fire Zone 34Y Pipe Area, Fire Zone 40Y Corridor, El. 372', Eire Zone 98J III.G.3 Lower North Piping Penetration Area, Fire Zone 53Y Yard Area Manholes,1MH09 and IMH10 The acceptability of these requests is addressed below. More details are contained in the NRC staff's related Safety Evaluation (SE) dated March 22, 1983, which is included herein by reference.
IV.
Intake Structure, Below El. 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.
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This zone consists of the service water pump intake bays; th,erefore the water level in the intake bays precludes the possible accumulation o
of transient combustible materials as anticipated,in other plant areas.
Beca0se the likelihood of an exposure fire is low, these alternative features compensate for the required suppression system and provide a level of fire protection equivalent to that required by Section III.G.
of Appendix R.
Therefore the exemption 'is granted.
Intake Structure, El. 354' The 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 than 20 feet with no intervening combustible or fire hazards, and also to the extent it requires an automatic fire suppression system.
This area contains redundant cable trays and conduits for the service water pumps and discharge valves. This fire area is provided with a smoke detection system. The cables for the service water pump discharge valves are separated by only 16 feet.,The 1.icensee,will provide a one-hour barrier for the conduit and trays providing power for one of the two sets of three valves constituting one complete path from the swing pump.
Because of the low in-situ fire load, separation between cables, large room volumes,' and detection system, there is reasonable assurance' t-that one train of service water pumps will be maintained free of fire damage in the time interval required for fire brigade response to i
extinguish a fire. The level of protection which will be provided in' this area in conjunction with the one-hour barriers provides a level
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' of fire protection equivalent to Section III.G of Appendik R.
Therefore, the exemption is granted.
Intake Structure
- El. 366' The 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 than 20 feet with no intervening combustible or fire hazards, and also to the extent it requires an aut'omatic fire suppression system.
The uppermost level of the intake structure is at elevation 366 feet, and contains the A and B trains and swing service water pump motors, valves and cables. The pump motors are situated several feet below the ceiling.
In our opinion, thet. hot gas layer will not extend to this level. Each pump motor contains s1x gallons of lubricating oil.
Floor drains are installed in the vicinity of each pump to collect and drain any potential lube oil leaks.
Redundant discharge valves are separated by approx'imately 5 feet, on opposite sides of missile barriers situated between the pumps..
Because of the low in-situ fire load, large room volumes'and the partial width missile barriers installed between each pump, arid the ceiling height above the pumps, there is reasonable assurance that one train of service water pumps will be maintained free of fire damage in the time interval required for fire brigade response' to extinguish an exposure fire. Although the pump discharge valves are separated by approximately five feet, they are effectively shielded from an exposure fire by the intervening missile barrier. These alternative features compensate for the automatic. fire suppression system required by Section III.G and provide a level of fire protection equivalent to the e
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.r technical requirements of Section III.G. of Appendix R.
Therefo'e, r
the exemption is granted.
Yard Area Manholes (IMH04 and 1MH06)
The licensee requested exemption from Secti'on III.G.2 to the extent this section requires: 1) separation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet with no inter'vening combustible or fire hazards, 2) enclosur,e of cable and equipment and associated
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non-safety circuits of one redundant train in a fire barrier having a one-hour rating, 3) fire detectors, and 4) automatic fire suppression system installed in the fire area.
This fire area consists of two manholes which are concrete
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bunkers approximately 5 feet by 5 feet by 5 feet,- and are located remote from the remainder of the plant. 'The power cables for redundant trains of service water pumps are located in close proximity inside the manholes. The manholes are not ventilated and can be accessed only by lif ting the concrete hatches with a crane. The licensee will fill the manholes with a non-combustible material such as sand or vermiculite.
Filling the manholes with sand or vermiculite will prevent a f' ire from occurring in the manholes and,. therefore an adequate level of fir _e protection will be provided equivalent to Section III.G of Appendix R.
Therefore, the exemption is granted, i
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o Radwaste Processing Area, Waste Monit6r Tank Room Fire' Zone 20Y The licensee has requested exemption from.Section III.G.2 to the extent it requires full coverage with an, automatic fire suppression system.
The treated waste monitor tank room contains both borated water storage tank (BWST) dropline valves and associated cables. The room is of reinforced concrete construction and is approximately 37 feet by 34 feet with a 17-foot' ceiling, and contains no in-situ combustibles.
The redundant BWST valves are located near the ceiling level and are separated by approximately four feet.
Ionization detectors, portable fire extinguishers and manual hose stations are available throughout the entire fire area. The licensee will install a one-hour rated fire barrier to protect one train of conduits associated with the BWST valves and install a partial coverage sprinkler system for the valve area. This zone also has automatic fire detection.
Because there are no in-situ combustibles in this room, an exposure fire would involve transient combustibles. Due to the limited personnel access to this area for health physics reasons, it is unitkely that a large quantity of transient combustible materials could accumulate.
Therefore, any potential fires in this area would be' of limited severity and duration.
Due to th'e considerable heat sink provided by the concrete floor, walls, and steel tanks in the area, there is slight possibility that a fire could damage both redundant BWST valves before actuation of the detection and automatic suppression systems. The one-hour rated
e-barrier between redundant conduits wil'1 provide an added margin of
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safety against premature ' fire damage.
The alternative protective features provided for the BWST dropline valves provide a level of fire protection equivalent to Section III.G.
of Appendix R.
Therefore, the exemption,is granted.
Radwaste Processing Area, Make-up Pump Rooms
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and Adjacent Corridor, Fire Zone 20Y
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The licensee requested exemption from Section III.G.2 to the extent it requires an automatic fire suppression system.
This section of the fire area is L-shaped and consists of a corridor and the make-up pump cubicles at the end of the corridor.
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The make-up pumps are in three adjacent cubicles approximatefy 10 feet
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by 20 feet. The pumps are separated by less than 20 feet. Physical separation between.the pumps is provided by 8-foot, partial height walls. The ceiling height in this fire area is 17 feet. One of the three pumps must be maintained free of fire damage to safely shut down the plant. Redundant cables for the pumps a.re routed in c.onduit.
Access to these areas is restricted for health physics reasons and partial height walls are provided between the pumps. One-hour fire barriers will be provided for the trays and conduits associated with power for the pump and suction valve of the swing and one other pump within each individual _ pump room. Portable fire extinguishers, manual hose stations and a smoke detection system are provided in the area. These features, in conjunction with one-hour barriers, will mitigate che onset of cable damage for a sufficient time period to enable the fire brigade to respond and extinguish a fire prior to damage of both trains.
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The resulting protection for the make-up pump rooms and the adjacent corridor will prov.ide a., level of fire protection equivalent to Section III.G of Appendix R.
Therefore, the exemption is granted.
Containment Building, Fire Zones 32K and 33K The licensee requested exemption from Section III.G.2 to the extent it requires separation of ca'bles and equipment and associated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet with no interve.ning combustible or fire hazards.
For the purpose of analys'is, the licensee has subdivided the containment building into, two fire areas. There is no fire barrier between the two fire areas. The separation of cables and equipment within each fire area is such that only one division of equipment is located in each fire area. Considering intervening combustibles in the form of non-safety related cable trays, wNich provide a potential path for the spread of flame from one fire area to another, the minimum separation distance between all redundant equipment in the two fire i
I areas is less than 20 feet. The fire area in' the north half of the cont,ainment building contains two-decay heat drop line (RHR letdown) valves, in series. A spurious operation of both valves-could cause i
breach of primary system integrity. This action could take place if a short, phase-to-phase in a specific manner involving the power cables
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t'.o the valves, wo01d occur. The power cables are routed in close proximity in t'his area.
Fire stops have been installed in th'e cable tra)s to prevent the '
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l spread of _ flames along the cables from one fire area to the other. Both fire areas are protected by a partial coverage smoke detection system.
Manual hose stations and an oil collection system for the reactor
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coolant pumps ar'e also' provided. Due to the restricted access to this area, the probability of an exposure fire from the accumulatidn'of tra'nsient combustibles which could potentially bypass the cable tray fire stops is low. The fire stops installed in the intervening cable trays pro' vide reasonable assurance that although redundant trains are not separated by the required distance free of intervening combustibles, one train will be maintained free of fire damage.
Because the am'ount of in-situ combustibles is low in this area and early warning detection is provided, the probability of a fire which could damage both RHR valve conduits is low. We believe that the probability that this damage would occur in such a specific manner is also low. This combination of conditions provides reasonable
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assurance that a' spurious operation of both valves in the RHR system' is not likely to occur.
Based on the above, the NRC staff concludes that the existing level of protection inside the containment provides fire protection equivalent to the technical requirements of Section III.G of Appendix R.
Therefore, the exemption is granted.
Pipe Area, Fire Zone 34Y The licensee requested exemption from Section III.G.2 to the extent it requires an automatic fire suppression system.
This fire a'rea is a passageway bounded by reinforced concrete walls.
The ceiling height is 17 feet for a portion of the area and 11 feet for the remainder of the area. The redundant cables for the A, B, and swing service water pumps are routed within seven. inches.near the ll-foot ceiling level. Redundant power cables for the decay heat e
I pumps are also routed thtough this area. These cables are routed vertically a.nd' are separated from each other and from the'other horizontal cables by greater than 20 feet. All cables in the area, are routed inside conduits. Only one service water pump and one decay heat pump are needed for shutdown.
Smoke detectors and por^ table fire extinguishers are provided.in the area. The licensee will enclose the cables needed for two service water pumps in one, hour rated fire barriers. The in-situ combustible
- loading in this fire area is negligible, therefore, any postulated fire would involve transient combustible materials. Such a fire would most likely be of limited severity in a corridor area where little maintenance activities are performed. The installed early warning detection system, in conjunction with Ehe.one-hour fire barrier for the
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protection of two service water pump cables, and the greater than 20 feet separation.of the decay heat pump cables provides reasonable l
l assurance tFat one train of components needed for safe shutdown will be maintained free of fire damage.
Based.on the above, the NRC staff concludes that the level of protection in this area -is equivanent to that required by Section III.G of Appendix R.
Therefore, the exemption is granted.
Pipe Area, Fire Zone 40Y
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The licensee requested exemption.from Section III.G.2 to the extent it requires an automatic fire suppression system.
This area is a narrow passageway approximately 12 feet by 90 feet with a 12-foot ceiling. The floor, walls, and ceiling assemblies are reinforced concrete. The redundant cables for the A, B, and swing service water pumps are routed in conduit in close proximity G
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- at the ceiling 1'evel. The licensee will enclose' the power cables
.for each of two service water pumps in a one-hour rated fire barrier.
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There are no in-situ combustibles in the fire area. Only one service water pump is needed for shutdown. Access to this fire area is restricted and can be gained only via a locked, steel hatchway, and a vertical l' adder. Smoke detec. tion and portable fire extinguishers are provided in the area. Manual hose stations are available in adjacen,t areas.
Because there are no in-situ combustibles in this area, any j
postulated fire would involve transient combustible materials. Restricted access to this area via a vertical ladder makes the probability of a significant quantity of combustible transient materials accumulating low. A fire in this area would therefore be of limited severity and duration. The installed early warning detection system would be able i
to promptly detect' incipient fire conditions, and the one-hour barrier will maintain the integrity of the cables until the fire brigade is
.able to respond and extinguish the fire. Although access to this area
. is restricted, the. fire brigade should be capable of reaching this area within a few' minutes after an alarm is received in the control room.
This combination of alternative protective features provides reasonable assurance that one train of equipment necessary for. safe shutdown will be maintained free of fire damage.
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__._The level of existing protection for this pipe area, in conjunction with the one-hour barrier, will provide a level of fire protection i
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Therefore, the exemption is granted.
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,s Corridor, El. 372',' Fire Zone 98J The licensee has indicated that enclosure of the corridor A-train conduits 4n a one-hour rated fire barrier and separation of t'he O.C.
equipment room from the corridor by three-hour rated fire barriers will be provided. With these modifications, the area will comply
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with Section III.G. of Appendix R, and no exemption is needed.
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Lower North Piping Penetration Area, Fire Zone 53Y Yard Area Manholes, IMH09 and IMH10 The licensee has provided alternate shutdown capability for the following areas in Unit 1 and requests an exemption from providing the fixed extinguishing systems as required by III.G.3 in these areas:
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a) Lower North Piping Penetration Area, Fire Zone 53Y j
b) Manholes IMH09 and 1MH10.
The combustible loading in these zones is negligible. The redundant equipment in these a' eas is primarily one system, the diesel fuel r
transfer pumps.
These fire zones represent a similar configuration, i.e., combustible loading is l'ight, 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 will not significantly increase the level of fire protection in these areas.
The existing fire protection, in conjunction with alternate shutdown capability in these 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.
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' 7590-01 V.
y Accordirigly, the Comission has determined that, pursuant to 10 CFR 50.12, the exemptions requested by t:.e licensee's letters as referenced and discussed in III. and IV. above are authorized
' by law, will not endanger life or 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 environm, ental 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 22,1983related to this action is available for public inspection at the Commission's Public Document Room,1717 H Stree', N.W., Washington, D.C.
20555 t
and at the Tomlinson Library, Arkansas Tech Universi.ty, Russellville, Ark'ansas 72081. A copy may be obtained upon request addressed to the U.S. Nuclear Regulatory Commission, Washington, D.C.
- 20555, A.ttention: Director, Division of Licensing.
I Thjs Exemption is effective upon issuance.
FOR THE NUCLEAR ULATORY COMMISSION
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9 - d-l f Robert A. -Purple, Deputy Director Division of, Licensing Office of Nuclear Reactor Regulation' t
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l Dated at Bethesda, Maryland l
this 22nd day of March'1983.
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