ML17333A905
| ML17333A905 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 07/25/1995 |
| From: | Gerwe B, Mangan P, Papps R AMERICAN ELECTRIC POWER CO., INC. |
| To: | |
| Shared Package | |
| ML17333A902 | List: |
| References | |
| GL-86-10, NUDOCS 9705300082 | |
| Download: ML17333A905 (20) | |
Text
SRC aCmaZC arran O6 lo Tncamcar.mrs.rmVZcer hppendix R Section ZZI.O.2(b), Tw'nty Foot Separation Between Redundant C~.lento With No Znthrvening Cembuetibles Pire Zone 6M and Fi e Zone 5S Prepared by.-Fire prot ion engineer<ann)rrmi by: R.S.Pappe-ire Protection co currence.C.an-Appendix R r tor Concurreuce P.J.Ruao-Plant PS,ro Protection Syotce Rnq.concurrence Nuclear Safety Revf.ev: J+Bi ,z/gseed-Sec n Mgr., NOS Section rp Approved by: J.D eo-Section Man~ger, (g e/q NBSP Section 9705300082 97052i PDR ADGCK 05000815 P PDR Boundary Evaluation Technical Evaluation 11.42 Rovieion 0 Page I, of ll Fire Protection Technical Evaluation Appendix R Section III.G.2(b)
Twenty Foot Separation Between Redundant Components With No Intervening Combustibles
~Pur ose The purpose of this technical evaluation is to review that portion of Fire Zones (FZ)6M and 6S designated as a twenty foot separation space within the same fire area with no intervening combustibles.
This review will evaluate the ability of tne"twenty foot wide separation space" to prevent the spread of fire between FZs 6N and 6S and to maintain safe shutdown capability for both units'n addi=ion, this evaluation will determine the impact that the twenty foot wide space will have on other evaluations or exemption requests previously performed and contained in the Fire Protection Program Manual (FPPM).The twenty foot separation spac a is defined in accordance with the latest Appendix R analysis.This separation space is intended o represent a definitive portion of a fire zone(s), 20 foot in width, that spans from one fire barrier to another along an imaginary boundary.This imaginary boundary occurs where a common Unit 1 and 2 fire zone (6M)abuts a Unit 2 fire zone (6S).The separation space is used to provide appropriate separation between a Unit 1 Appendix R analysis area from a Unit 2 Appendix R analysis area.Descri tion Appendix R t".10CFRSO,Section III.G.2(b) states the foixowi"" requirements
'or separation of reaundant components within the same fire area: "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.In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area".Since no physical barrier existed or could be easily provided between FZs 6N and 6S, the compliance strategy method of III.G.2(b) was seen as a logical means of providing the needed separation between the Unit 1 and 2 analysis areas.The 20 foot wide area exists along the border between FZs 6M and 6S, but spreads predominantly to the south into Unit 2 (FZ 6S).The area is bounded on the east by the"L" shaped labyrinth wall to the seal water filters and the western wall of the north safety injection pump cubicle Boundary Evaiuation Technical Evaluation 11.42 Revision 0 Page 2 of 11 (FZ 65B).In the north-south direction, the separation space is located between the"L" shaped wall on the north and on the south by the wing wall that projects out from between the safety i.njection pump cubicles (FZs 65A and 65B).The distance between these two concrete walls is approximately 25 feet.On the western side of the separation space, the concrete wall on the southern side of the boric acid tank area provides a barrier to the north.Additionally, the concrete walls to the gas decay tank area provides a southern and western boundary to the separation space.The separation space also extends down the corridor formed between the boric acid tank area and the gas decay tank area.Refer to Sketch 1 showing the area of the plant containing this 20 foot wide separation space.This represents a repositioning of the 20 foot separation space more into FZ 6S than was previously analyzed.The SSCA, Revisions 0 and 1, Cha~ter 8 ident'fied modifications that were to be made to the plant in order to comply with Appendix R,Section III.G., (Note: This modification chap er has been transferred from the SSCA to the FPPM, where it remains as Chapte" 8.)Section 8.3.1 identified that the open cable trays traversing the zones from the north side to the south side have been appropriately Eire-stopped to prevent fire propagation from one section o'hr~fire zone (FZ 6N)to the other (FZ 6S).The trays were originally fire stopped with a silicone foam fire seal within the trays.Traditionally, the t=ay would also be wrapped for several feet with a noncombustible (metal)material in the immediate area of the fire seal.However, in these instances, the cable trays were wrapped with Thermo-Lag fire barrier materials for tne entire 20 foot length between the silicone foam fire stops.In these prior analyses, the 20 foot wide separation space was applied to only those cable trays traversing
~he zones (FZs 6N, 6M and 6S)from north to south and included only those areas directly beneath the trays.~Today, this separation space is conservatively assume o extend across FZs 6M and in an east-vest direction until the physical barriers forming the corridor between the boric ac'.'.tank and gas decay tank areas are able to limit the straigh" line distance between the areas to the north and south of the separation space.The trays that only traversed north-south are located on the western side of the zones and are over 8 feet from the next closest tray.The eastern two trays traversing north-south that eventually turned east were also fire-stopped and wrapped.One of these trays (2AZ-C62)was required to be wrapped per III.G.2(c) by prior analyses.This tray connects with other trays that were also required to be wrapped which traversed east (2AZ-C75)or vertically (2AZ-C58)within the zone.The cables within these trays are no longer required to be wrapped per III.G.2(c) by our latest Appendix R analysis.Since the trays turned away from the opposite unit, they would not result in a fire propagation path to the other unit.Boundary Evaluation Technical Evaluation 11.42 Revision 0 Page 3 of 11 Only one cable tray (2AZ-P10)was partially wrapped through the separation space.This tray was wraoped where it was physically connected to tray 2AZ-C62.When considered among all the other wrapped cable trays, the partially wrapped tray can be viewed as an isolated cable run.Additionally, since this tray also turned east, it would not have resulted in direct fire propagation between cable trays of the opposite unit.There are no other cable trays that run north-south in the immediate area of where the trays turn east to cause a crisscross of trays that would allow the fire to propagate from one unit to the other.The closest non-fire-stopped north-south trays-re near the elevators, which are more than 20 feet east of'he separati~n space.Fire Zo." 6M is the Auxiliary Building, West End-Middle Section.This zone is'.seated at the 587 ft.elevation and contains safe snutdown cables for both units.Fire Zone 6H forms a buffer between the Unit 1 FZ 6H and Unit 2 FZ 6S.This fire zone is part of a much larger fire area, Fire Area (FA)E.This fire area also contains FZs 5, 6A, 6N, 6S, 61, 64A, 64B, 65A and 658.This fire area'nc'udes much of the remaining portions of the Auxiliary Building at this elevation, including general'access areas of both units (FZs 5, 6N, 6M and 6S), the Unit 1 and 2 El.609 pipe tunnel (FZ 6A), the spray additive tank room (FZ 61)and Unit 1 and 2 safety injection pump cubicles (FZs 64A, 64B, 65A and 65B)~Fire Zone 6S is the Auxiliary Building, West End-South Section.This zone is located at the 587 ft.elevati.on and contains safe shutdown cables and components for Unit 2.This fire zone is also part of FA E as explained above.Safe Shutdown E i ent The Appendix R safe shutdown analysis has evaluated the imp:t of a fire in this location.Safe shutdown analysis area 5 (AAS)conta, zs FZs 5, 6A, 6M, 6N, 61, 64A and 64B.Safe shutdown analysis area 6 (AA6)contains FZs 5, 6A, 6M, 6S, 61, 65A and 65B, The twenty foot wide separation space described in this evaluation is located predominately in FZ 6S and prevents the propagation of fire between AA5 and AA6.AA5 contains mostly Unit 1 safe shutdown components and cables and some cables associated with Unit 2 safe shutdown components.
AA6 contains mostly Unit 2 safe shutdown components and cables and some cables associated with Unit 1 safe shutdown components.
The safe shutdown analysis has demonstrated that a fire in either analysis area will not prevent the safe shutdown of either unit.Safe shutdown compliance strategies of both analysis areas rely on a combination of strategies including repairs, redundant equipment and systems outside the area (Appendix R Section III.G.1), and the wrapping of redundant safety circuits within the same fire area by a 1-hour.fire barrier (Appendix R Section III.G.2.c).
Analyses AA5 and AA6 have demonstrated chat no wrapping of cables is required within the 20 foot separation space to satisfy compliance with Appendix R Section III.G.2.c.
Boundary Evaluation Technical Evaluation 11.42 Revision 0 Page 4 of 11 Fire Protection E i ment Fire Zones 6N, 6M and 6S are provided with an ionization smoke detection system and dry pilot preaction spri."klers.
The detection and sprirzkler systems are installed throughout the normally accessible portions of the fire zone.The sprinklers in the area of the 20 foot separation space are located beneath the obstructions and cable trays.The sprinklers were installed to extinguish floor based fires tl at would threaten the cable trays in accordance with our commitments to Appendix A of BTP APCSB 9.5-1.In addition, in FZs 6N and 6S sprinklers are installed in a close spaced configuration around the perimeter of the open stairway to form a water curtain between fire areas above and below.Additionally, these fire detection and suppress'on systems also provide protection in the normally accessible portions of adjacent FZs 5, 64Ag 54B, 65A and 65B within FA E.The open stairways of FZs 5 are also protected by a water curtain between.'e areas above and below.Fire Hazards Anal sis The normal fire loading for FZ 6M is considered low with a combustible loading of 27,000 BTU/sq.ft.
for an equivalent fire severity of 20 minutes.(The actual combustible loading is under 21,000 BTU/sq.ft.
having a fire severity of less than 16 minutes.)The normal fire loading for FZ 6S is considered low with a combustible loading of 27,000 BTU/sq.ft.
for an equivalent fire severity of 20 minutes.(The actual combustible loading is under 15,000 BTU/sq.ft.
having a fire severity of less than 12 minut~s.)Plant components within the 20 foot wide separation space generally includes a valve control center, a lighting cabinet, process piping and instrument ion, conduits and cable trays.The 20 foot wide separation space is toured daily to ensure that this space is kept free of permanent combustibles in accordance with this technical evaluation.
The tours are conducted under a plant fire protection administrative guideline.
The presence of any transient combustibles within the 20 foot wide separation space would be accounted for in the total combustible loading for the zones under the plant's transient tracking program.If an exposed transient combustible were to remain within the 20 foot wide separation area for an extended period of time, plant policy is to establ:sh a fire watch in the area.With the existence of the automatic detection and suppression systems within FZs 5, 6N, 6M, 6S, 64A, 64B, 65A and 65B, a roving fire watch in FZs 6M and 6S is an acceptable compensatory measure until the combustibles are removed.Boundary Evaluation Technical Evaluation 11.42 Revision 0 Page 5 of ll There are no significant ignition sources present or fire hazards within the 20 foot wide separation space.However, if a fire were to start within or near this separation space the ionization smoke detection system and dry pilot portion of the sprinkler system will give alarm.notification within the control rooms'.The control room operators would then initiate fire brigade activities.
The automatic sprinkler system will control and/or extinguish a floor based fire before the fire brigade arrives.Fire spread between the units and its affect on safe shutdown of the plant has been previously analyzed in the Safe Shutdown Capability Assessment (SSCA)and FPPM.These analyses rely on Appendix R compliance strategy III.G.2(b) methodology to maintain the separation of Unit 1 and 2 analysis areas AA5 and AA6.This complian e strategy, is maintained by the presence of the 20 foot wide separation space plus the existence o automatic fire detection and suppression within the separation space and throughout the normally accessible portions of the fire area.The presence of partial fire area detection and suppression systems has been reviewed under Techn'cal Evaluation 10-A and found to be acceptable.
Additional guidance on Appendix R compliance is provided in NRC Generic Letter 86-10, Implementation of Fire P"otection Requirements.
Sections 3.5 and 3.6 provide guidance on separation oi redundant circuits and intervening combustibles with regard to the 20 foot wide separation space.These sections are paraphrased below: 3.5.1, It is acceptabl~
to erect a partial one-hour rated barrier for portions of circuits with less than 20 feet separation, as long as 20 feet of horizontal separation exists between the redundant unprotected portions of the c'rcuits.Additionally, no intervening combustibles or fire hazards are to exist in the 20 foot separ-"'an apace and the fire area is to be protected by automatic fire detection and suppression.
3.6.1 An isolated cable run is considered to be a negligible quantity of combustible material.If more than negligible quantities of combustible materials exist between redundant shutdown divisions, an exemption request should be filed.Justifications for past exemptions have been based on>1)large horizontal spatial separation between redundant divisions; all cables qualified to IEEE-383, 2)presence of automatic fire suppression svstem over the intervening combustible, 3)presence of fire stops to inhibit fire propagation in intervening cable trays, 4)likely propagation direction of burning intervening combustibles in relation to the Boundary Evaluation Technical Evaluation 11.42 Revision 0 Page 6 of 11 0
shutdown divisions and 5)available compensating active and passive f're protection.
3.6.2"No intervening combustibles" means that there is no significant quantities of in-situ materials which will ignite and burn located between redundant shutdown systems.The amount of such combustibles that has significance is a judgmental decision.Transient materials are not considered as an intervening combustible; however, they must be considered as part of the overall fire hazard within the area.Cables in cable trays that are not enclosed by fire rated enclosures a e considered as intervening combustibles.,However, cables in trays having solid sheet metal bottom, sides and top and protected by automatic fire detection and suppression systems and supported by a fire hazards analysis have been found to be acceptable under the exemption process.3.6.3 Cables in conduits are not considered to be an intervening combustible.
~Oil (a combustible liquid)in closed containers which are in accordance with NFPA 30 are not considered to be an iatervening combustible.
As discussed above, the 20 foot wide separation space contains cable trays which pass through this space in a north-south direction.
These cable trays traverse north from FZ 6S into FZ 6M, where all but one turn east.The trays have been provided with a Thermo-Lag fire barrier wrap through the 20 foot separation space in accordance with our prior analysis.At each end of the wrapped section, a cable tray fire stop was pro~~ueo.The cable tray fire stops consist of silicone~~am penetration
.re sealant material.One cable tray was wra'pped for only a portion of the distance within the 20 foot wide separation space.The fire stopping and wrapping of the cable trays with a fire resistive.
material initially conformed to the guidance provided in GL 86-10 Sections 3.5.1 and 3.6.1.However, as explained below, the NRC has required the removal of all Thermo-Lag materials within the 20, foot separation space.Two of the western trays traverse directly from Unit 2 FZ 6S into FZ 6M where they empty into an electrical junction pan.From the pan, two trays travel east, two more travel west and a single tray (2AZ-C90)continues north into Unit 1 FZ 6N.The remaining cable trays from each unit that enter FZ 6M change direction and run in the east-west direction, resulting in Unit 1 and Unit 2 cable trays running parallel to each other.The routing of the cable trays in this manner restricts the propagation of fire directly from one unit to the other as discussed in GL 86-10, Section 3.6.1.Boundary Evaluation Tech".ical Evaluation 11.42 Revision 0 Page 7 of 11 Two small electrical troughs exist within the 20 foot wide separation area along the wall surrounding the boric acid tank area.These troughs contain instrumentation cabling for the instrumentation located on the wall.Each trough is a three sided metal enclosure mounted with the fourth side against the wall.The bottom trough is located near the floor while the top trough is located approximately six feet above the floor.The design of the trough allows only small areas where cabling is exposed.The trough~are located away from other=able trays.These trays are considered to be isolated tray runs containing negligible quantities of combustibles as discussed in GL 86-10 Section 3.6.1.In a letter dated March 13, 1995 to Mr.A.Marion of Nuclear Energy Institute (NEI), the NRC states that"the staff will not accept the use of the NEI guide to justify the use of Thermo-Lag materials where noncombustibles materials are specified by NRC fire protection requi~ements or to assess the co;-.~ustibility hazards presented by Thermo-Lag materials....
As an alternative to the NEI guide, th'e staff recommends that licensees reevaluate their use of Thermo-Lag
...as an enclosure to create a 20-foot combustible-free zone be ween redundant trains and seek other solutions Examples of possible solutions include the following:
...(3)replace>" ermo-Lag barriers used to create combustible-free zones with noncombustible barrier materials..." The NRC further states in Enclosure 2 of this letter, that Thermo-Lag is combustible as defined by previously established NRC fire protection guidelines, that when exposed to fire hazards representative of nuclear power plants that it would release flammable vapors, ignite and burn.The staff has also concluded that"Thermo-Lag 330-1 material located between redundant safe shutdown divisions should be considered an intervening combustible material." Therefore, based on this information, Thermo-Lag materials installed within the 20 separation space are to be removed.In addi"'a o the wrapped cable trays, several conduits and o""er miscellaneous intervening steel have been wrapped with Thermo-Lag material within the 20 foot separation area.Existing concrete walls help provide natural separation of FZs 6M and 6S through a portion of this separation space.As a result, these walls form passive boundaries for a portion of the 20 foot wide separation space.These walls include the concrete wall directly south of the boric ac'd tank area and the"L" shaped concrete wall between the elevator shaft and the reactor coolant filter/seal water filter cubicles.The 20 foot separation space does not extend into the filter cubicles or the gas decay tank areas due to the labyrinth design of the filter cubicles and tank area, the lack of combustibles in these areas, their wall construction, the upgrading or the"L" shaped wall around the filter cubicles with penetration seals and the classification of the filter cubicles and gas decay tank area as ALARA areas.Boundary Evaluation Technical Evaluation 11.42 Revision 0 Page 8 of 11 One of the penetrations in the"L" shaped concrete wall contains an undampered duct.The duct is part of the Auxiliary Building ventilation system and is 12" x 14" in sire.The absence of the fire damper will reduce the overall rating of the seal.Fire testing and NFPA 90 support the position that no fire damper is required for duct work penetrating a one hour fire wall.Additionally, the other 41 igating features of the area, including construction and low fire loading, off set the absence of a fire damper and it will not alter the basic reasons for ire sealing the wall.The penetration and wall are being fire sealed in order to help define the 20 foot separation space separating Unit 1 FZ 6N from Unit 2 FZ 6S.Additionally, the sealing of the barrier will aid in reducing the amount of floor area within the separation space by the presence of rated construction.
Modifications Re ired Due to the NRC letter of March 13,'995, the Thermo-Lag fire barrier wraps installed on the cable trays, conduits and/or intervening steel within the 20 foot separation space are to be removed.Fire stops are to be installed within the north-south cable trays as originally committed in order tc create a 20 foot separation space to inhibit fire propagation in the intervening cable trays between FZ 6N and 6S.As a conservative measure, the fire-stopping of cable trays will include the cable trays that turn east once they exit the separation space, as well as the cable trays tnat traverse only in the north-south direction.
The north-south cable trays that are to be fire stopped include as a minimum;2AZ-C36, 2AZ-C37, 2AZ-C62, 2AZ-P3/2AZ-P4/2AZ-P6 and 2AZ-P10.The fire stopping will include a silicone fire seal within the cable tray and, a noncombustible material wrapped around the tr~for several feet in the immediate area of the silicone fire seal.The cable trays will not be wrapped ith the noncombustible material fo the entire 20 foot leng-h between the fire seals"~done previously.
The 20 foot separation space is to be positioned within the area bounded between the"L" shaped wall on the north and on the south by the wing wall that projects out from between the safety injection pump cubicles (FZs 65A and 65B).With the minor repositioning of the 20 foot separation space, the prior fire stops within the cable trays (which upon removal of the Thermo-Lag material will consist only of 12 inches of silicone foam)will no longer be used.These prior fire stops will be left in the trays as a conservative fire protection measure that will additionally retard fire propagation along the trays.Since the distance between these walls is approximately 25 feet, this allows flexibility with final placement of the separation space when accounting for field conditions and ease of installation.
Boundary Evaluation Technical Evaluation 11.42 Revision 0 Page 9 of ll Fire barrier penetrat'on seals are to be installed in the concrete walls forming the pass've boundaries of the separation space.These walls include as a minimum;1)the east-west wall located directly south of the boric acid tanks and 2)the"L" shaped wall between the elevator shafts and the reactor coolant filter/seal water filter cubicles.Conclusion Based on the above evaluation and proposed modifications, reasonable assurance is provided that a 20 foot wide separation space along the boundary between FZs 6M and 6S will prevent the spread of fire between these two fire zones and maintain safe shutdown capability for both units.In addition, this evaluation does not adversely impact other evaluations and exemptions contained in the FPPM.The bases that justify this conclusion a:e summarized as follows: 1)It has been determined that for a ire in e'ther analysis area, AAS or AA6, the fire will not prevent Unit 1 or Unit 2 from achieving safe shutdown.2)The normal fire loading for these zone is considered low.3)There are no significant ignition sources present or fire hazard present within the 20 foot wide separation space.4)Fire Zones 6M and 6S are provided with an ionization smoke detection system and an automatic dry pct sprinkler syst: em within the normally accessible portions of the zones.The smoke detection and dry pilot portion of the automatic sprinkler system will give notification of a fire with.n this area.Additionally, these fire detecti: and suppression systems provide coverage.;the fire zones ad'~cent to 6M and 6S.5)Daily tours are performed for the 20 foot wide separation space to ensure that the space remains free of permanent or long term transient combustibles.
6)The monitoring of any transient combustibles within the 20 foot wide separation space and inclusion of these combustibles in the total combustible loading for the fire zones.The establishment of fire watches for any long term transients.
7)Many of the north-south cable trays near thr.area of concern turn east changing direction once they approach (from Unit 1)or exit (from Unit 2)the separation space, which will prevent the direct propagation of fire into the other unit via these trays.Boundary Eval ation Technical Evaluation 11.42 Revision 0 Page 10 of 11 8)The presence of fire stopped cable trays within the 20 foot wide separation space.'9)The two isolated instrument troughs in the 20 foot wide separation space represent a negligible combustible.
10)Existing concrete walls that are to be upgraded to fire rated barriers provide passive boundaries for tne 20 foot wide separation space.11)Additional modifications would not signific~ntly enhance fire protection safety above that provided by present commitments.
Boundary Evaluation Technical Evaluaticn 11.42 Revision 0 Page 11 of 11
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Fg/, I a R-ANERCCW ELECTRIC POWER Date July 21, 1995 suspect Donald C.Cook Nuclear Plant Units 1&2 Nuclear Safety Evaluation for Fire Zones 6M&6S;Twenty Foot Separation Between Redundant Components With No Intervening Combuscibles Fr<J.M.Girgis Io AEP:NRC:0692DB File Inc oductio The 10CFR50 Appendix R analyses of f:re zones 6M and 6S involve use of Section III.G.2 compliance strategy and feature a designated space (twenty fooc separation space)along the boundary between these zones using the compliance strategy mechods of Sec"ion III.G.B(b).
As a result of the recenc Append'x R revalidation project and che on-going Thermo-Lag resolution effort, changes to fire barrie..s within the twenty foot separacion space, and to che definition of the space itself, are now desired.The separation space is used to provide regulatory separation between Appendix R safe shucdown analysis areas 5 and 6.Accordingly, the purpose of this evaluation is to complete the necessary 10CFR50.59 evaluation, in accordance with the guidance provided in Generic Letter (GL)86-10, to determine acceptability of the proposed changes to the designated separation space.~Dtscuss o The"SAFE-SF TDCWN CAPABILITY ASSESS.".rNT AND PROPOSED PJODIFICATIONS" (SSCA), dated March 1983 (reference 12), and revision 1 to the SSCA, dated December 1986, include licensing commitments to ensure compliance with Section III.G.2(b).
Specifically, Section 8.3.1 of the SSCA requires that"The open cable trays traversing the"zone (6)from the north side to the south side vill be appropriately fire-stopped co prevent fire propagation from one section of che fire zone co the other."Section III.G.2(b) requires"Separacion of cables and equipment and associaced non-safety circuics of redundanc crains by a horizontal discance of more than 20 feet with no intervening combuscible or fire hazards." Trays traversing the designated 20 foot separation space from north to south were f're stopped and wrapped since prior Appendix R analyses considered cables located within these trays to be required for safe shutdown.The recent Appendi:: R revalidation project has demonstrated that cables within these trays are no longer required to be protected in accordance with Appendix R Section III.G.2(c).
Therefore, a 1-hour fire Intra-System AEP:NRC:0692DB FUe Page 2 July 21, 1995 wrap is not required for these trays.Also, it is noted that almost all of these trays travel from north to south and turn east shortly after exiting the designated separation space.Consequently, the likely propagation direction of fire along these trays precludes damage to redurdant equipment.
Only one tray which travels=from north to south through fire zone 6M also continues on into fire zone 6N.O.i March 13, 1995, NRC issued a letter (reference 18,'o the Nuclear Energy Institute (NEI)indicating that the Thermo-mg product is considered a combustible material and, therefore, should be removed from the 20 foot separation space.Accordingly, the proposed changes involve removal of Thermo-Lag fire barrier installed on cable trays, conduits, and/or intervening steel within the 20 foot separation space.Also, the 20 foot separat'on space will be redefined to conservatively include the entire width of fire zones 6M and 6S and will be shifted slightly to provide consistency in location betweer elevations.
As a result, the existing f're stops in these trays will be abandoned in place and an appropriate fire stop design will be installed at the new end boundaries of the 20 foot separation space.In addition, fire barrier penetration seals will be installed in the concrete walls forming the new passive boundaries of the separation space (see Tech Eval.11.42)./valuation The following evaluation has been completed in accordance with procedures 227000-STG-5400-01 and 227000-LTG-2300-05, in compliance with federal regulations 10CFR50.59, 10CFR50.48, and 10CFR50 Appendix A Criterion 3, and, consistent with the guidance provided in Generic Letter (GL)86-10, Section F.Further, the proposed changes were discussed with the Appendix R Project Manager and Cognizant Fire Protection Engineer, B.J.Gerwe.Assessment of Potential Impact on the FPA, SSCA, and FPPH As discussed with the Cognizant Fire Protection Engineer, the FHA is in the process of being revised to include the combustibility of Thermo-Lag ,material.
At this time, it has been decided not to show a reduction in total combustible loading in the associated areas due to the removal of Thermo-Lag material.This is a conservative position for the analysis.The Appendix R Project Manager has determined that the FPPM will require revision to reflect the described expansion and that the SSCA will not require revision because the modificatx:,n chapter has been transferred to the FPPM (chapter 8).Consideration of Combustible Loading and Distribution As described above, the propo"ed cnanges reduce combustible loading and will not increase combustible distribution (reference 16).Impact on Associated Circuits or Equipment Needed for Safe Shutdown The Appendix R Project Manager has reviewed Technical Evaluation 11.42 (reference 16)and has determined that the proposed changes, as described AEP:NRC:0692DB File Page 3 July 21, 1995 above, will not impac" associated circuits or equipment needed for safe shutdown.Impact on Appendix R Compliance Strategi e" for Cook Nuclear Plant The Appendix R Proj ect Manager has determined that the proposed changes will not impact Appendix R compliance strategy.Li censi.cg Commitments Assessmene A licensing document search has been completed and no licensing commitments could be identified"hat would preclude implementing the proposed changes.Also, Section 7.13 of the SSCA requested exemption from Appendix R requirements for damners located in fire zones 6M and 6S.By letter dated December 23, 1983 (reference 7), NRC provided the requested exemption.
The proposed changes to the 20 foot separation space would not require a revision to this previous exemption and, based on the above review, no add'ional exemptions are required to support the proposed changes.Impace on Fire Proeeceion Administrative Controls Based on the above review, the proposed changes will not involve additional or expanded exceptions to compliance with the Administrative Controls listed in Appendix A to BTP APCSB 9.5-1.Unrevi eved Safety Question Determination In accordance with the guidance provided in GL 86-10 (reference 4), the determination of the involvement of an unreviewed safety question defined in 10CFR50.59(a)(2) is provided below to address overall plant fire safety.Accordingly, the postulat d"accident previously evaluated" is a fire event (i.~., not a UFSAR chapter 14 design basis accidentg.
Does the proposed activity increa e the probability of occurrence of an accident previously evaluated in the UFSAR?No.The proposed changes are considered changes to passive fire protection features (i.e., fire barriers)used to protect systems required to achieve and maintain safe shutdown conditions.
As such, the proposed changes are not considered accident initiators.
Therefore, these changes will not affect the probabilities of occurrence of an accident considered in the UFSAR.Does the proposed activity increase the consequences of an accident previously evaluated in the UFSAR?No.The attached technical evaluation has concluded that the proposed changes, as described above, will prevent the spread of fire between the affected fige zones and maintain redundant safe shutdown capability (reference 16).Therefore, the fire protection features within fire zones 6M and 6S will continue to protect equipment necessary to mitigate the consequences of fire induced accidents.
As such, the proposed changes will not increase the AEP:NRC:0692DB File Page 4 July 21, 1995 radiological consequences of the accidents previously evaluated in the UFSAR.Therefore, these changes will not increase the consequences of an accident previously evaluated in the UFSAR.3.Does the proposed activity increase the probability of an occurrence of a malfunction of equipment important to safety previously evaluated in the UFSARV No.Pith consideration for items 1&2 above, the proposed changes will not challenge safety system performance or degrade required safe shutdown design basis capabilities.
Also, the Cognizant Fire Protection Epgineer has concluded that the fire protection measures available in these zones provide a level of protection commensurate with the fire hazards in the zones (reference 16).Therefore, the proposed changes will not increase the probability of an occurrence of a malfunct'on of equip nt important to safety previously evaluated in the UFSAR.Does the proposed activity increase the consequences of a malfunction of equipment iml ortant to safety previously evaluated in the UFSAR?No.An increase in the consequences of a malfunction of equipment must involve an increase in dose to the public.As stated in item 2 above, the proposed changes will not increase the radiological consequences of the accidents previously evaluated in the UFSAR.Therefore, these changes will not increase the consequences of a malfunction of equipment important'~safety previously evaluated in the UFSAR." es the proposed activity.create the possibility of an accident of a different type than any previously evaluated in the U"SARV No.Possible accidents of a different type are limited to accidents that are as likely to happen as those considered in the SAR.The Cognizant Fire Protection Engineer has reviewed the proposed cnanges and has, determined that the defense-in-depth fire protection available in these fire zones adequately protects the fire safety of the plant.Also, the removal of the Thermo-Lag material will be completed in accordance with plant procedures under PAR/jl2-P-0054 and, therefore, the potential risk of disturbance to the electrical trays will be minimal.Therefore, the proposed changes will not create the possibility of an accident of a different type than any previously evaluated in the UFSAR.Does the proposed activity c-cate the possibility of a malfunction of equipment important to safety of a different type than any previously evaluated in the UF:"AR?No.See item 5 above.
AEP:NRC:0692DB File Page 5 July 21, 19M 7.Does the proposed activity reduce the margin of safet>as defined in the basis for any technical specification?
No.Based on the above evaluations and reviews, the proposed changes, as described above, will not reduc;e the margin of safety as defined in the basis for any technical specification (reference 2).Conclusion The above described changes will not involve additional or expanded exceptions to compliance with the administrative controls listed Appendix A to PZP APCSB 9.5-1, or impact Technical Specifications.
The impact on the UFSAR has been reviewed and it was determined that revisions to the UFSAR will not be required, however, the PPPM vill need to be revi ed.Based upon the above evaluation, the 10CFR50.59 evaluation indicates that the proposed change will not constitute an unreviewed safety question per lOCFR50.59(a)(2), nor does i.t constitute a significant hazard to the health and safety of the.public.Therefore, Nuclear Safety concludes that the proposed changes re acceptable.
Finally, it is noted that the proposed changes do not represent a deviation from the guidelines listed in Appendix A to BTP APCSB 9.5-1 or from previous licensing commitments.
Ther fore, based on the above review, the identified changes do not require NRC notification, revie~or approval.However, in accordance with commitments made under AEP:NRC:0692DA, resolution of thermo-lag installations, at Cook Nuclear Plant will be summarized and forwarded to NRC in December 1996 (AEP:NRC:0692DB).
This evaluation completes the GL 86-10 review process and must be retained with all supporting documents for future NRC audits and reviews.References 1)UFSAR Sections,'..7, 7.7, 9.8.7, 10.6, and Chapters 13 6 14 2)Technical Specifications 3.3.3.7, 3/4.7.9, and 3/4.7.10 3)QAPD Section 1.7.19 4)Generic Letter 86-10, Section F, dated April 24, 1986 5)GL 86-10, Enclosure 2, Section 8.4, dated April 24, 1986 6)Safety Evaluation Report (SER), dated July 31, 1979 7)AEP:NRC:0692L 8)AEP:NRC:0692K 9)Submittal letters dated January 31, March 31, and October 27, 1977 10)Section D.l.(j)of Appendix A to BTP APCSB 9.5-1 ll')Safe Shutdown Systems Analysis (SSSA)12)SSCA, Sections 7.13 and 8.3, Rev.O, 03/83 and Rev.1, 12/86 13)Fire Hazards Analysis (FHA)14)Fire Protection Program Manual (FPPM)15)10CFR50 Appendix R, Sections III.G, III.K, III.L 16)NRC GENERIC LETTER 86-10 TECHNICAL EVALUATION 11.42, dated 07/95.17)Internal Memorandum from J.M.Girgis, date 11/03/93.18)Letter of March 13, 1995, from C.McCracken, NRC, to A.Marion, NEI.
AEP: NRC:06920B;""..e Page 6 July 21, 1995 Kee~ords fire barriers thermo-lag Approved By: J.Nu Kingseed, M ager ar Safety ATTACHMENT:
reference 16 cc: C.A.Dickey/R.B.Bennett (w/o)W.G.Smith/S.J.Brewer (w/o)D.H.Malin/C.C.Savitscus (w/o)J.D.Benes/B.J.Gerwe J.D.Gr'er/E.V.Gilabert P.J.Russell PRONET DC-N-6944 ATTACHMENT 3 TO AEP:NRC:0692DM TECHNICAL EVALUATION FOR AUXILIARY BUILDING FIRE ZONES 44N AND 44S