ML20236S402
| ML20236S402 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 11/12/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236S290 | List: |
| References | |
| TAC-55560, TAC-55831, TAC-63463, NUDOCS 8711250138 | |
| Download: ML20236S402 (24) | |
Text
_ _ _ _ _ . _ _ _ _
y ,
av n: ~ t ' '
W W ~ % ^ S
- OW' f
'o,, UNITED STATES 8 o NUCLEAR REGULATORY COMMISSION y E WASHINGTON, D. C. 20555 ENCLOSURE 2 j
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR' REACTOR REGULATION !
RELATIVE TO APPENDIX R EXEMPTIONS REQUESTED FOR PORTLAND GENERAL ELECTRIC COMPANY TROJAN NUCLEAR PLANT DOCKET NO. 50-344
1.0 INTRODUCTION
By letter dated July 31, 1984, Portland General Electric Company (PGE, the Licensee) requested exemptions from Section III.G of Appendix R to 10 CFR 50. By letter dated May 31, 1985, the Licensee submitted their safe shutdown analysis which provided further clarification of exemption requests already granted and identified additional exemption requests.
Supplemental infomation was also provided in submittals dated October 16, and November 17, 1986, and May 8, 1987. These additional exemption requests are the subject of this evaluation.
This safety evaluation is based in part on the attached Technical Evaluation Report (TER) generated by a NRR contractor, Franklin Research Center (FRC). This TER has been reviewed by the staff and it is in agreement with the conclusions reached in the FRC TER.
Section III.G.1 of Appendix R requires fire protection features to be provided for structures, systems, and components important to safe shutdown and capable of limiting fire damage so that:
- a. One train of systems necessary to achieve and maintain hot shutdown conditions from either the control room or emergency control l
station (s) is free of fire damage; and '
- b. Systems necessary to achieve and maintain cold shutdown from either i the control room or emergency control station (s) can be repaired within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
i Section III.G.2 of Appendix R requires that one train of cables and equipment necessary to achieve and maintain safe shutdown be maintained free of fire damage by one of the following means:
j
- c. Separation of cables and equipment and associated nonsafety circuits of redundant trains by a fire barrier having a 3-hour rating.
Structural steel foming a part of or supporting such fire barriers I 3
shall be protected to provide fire resistance equivalent to that required of the barrier.
1 8711250138 871112 4 I DR ADOCK 05
Y ut m. s A w u._.v n M M
- b. Separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards. In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.
- c. Enclosure of cable and equipment and associated nonsafety circuits of one redundant train in a fire barrier having a 1-hour rating. In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.
If the above conditions are not met,Section III.G.3 requires that there be an alternative or dedicated shutdown capability independent of the fire area of concern. It also requires that fire detection and a fixed suppression system be installed in the fire area of concern. These alternative requirements are not deemed to be equivalent; however, they provide equivalent protection for those configurations in which they are accepted.
Because it is not possible to predict the specific conditions under which fires may occur and propagate, the design basis protective features rather than the design basis fire are specified in the rule. Plant- !
specific features may require protection different from the measures specified in Section III.G. In such a case, the Licensee must demon-strate, by means of a detailed fire hazards analysis, that existing protection or existing protection in conjunction with proposed modifica-tions will provide a level of safety equivalent to the technical requirements of Section III.G of Appendix R.
In'sumary,Section III.G is related to fire protection features for ensuring that systems and associated circuits used to achieve and maintain safe shutdown are free of fire damage. Fire protection configurations must either meet the specific requirements of Section III.G or an alternative fire protection configuration must be justified by a fire hazards analysis. Generally, the staff will accept an alternative fire protection configuration if:
o The alternative ensures that one train of equipment necessary to achieve hot shutdown from either the control room or emergency control j station (s) is free of fire damage.
{
l o The alternative ensures that fire damage to at least one train of l equipment necessary to achieve cold shutdown is limited so that it can i
be repaired within a reasonable time (minor repairs using components !
stored on the site).
{
o Fire-retardant coatings are not used as fire barriers. {
i o Modifications required to meet Section III.G would not enhance fire protection safety levels above that provided by either existing or proposed alternatives.
- y. - ~ - _
_ ,# .. - u -.4 %
i o
Modifications required *v i ret Section III.G would be detrimental to overall facility safety.
NRR and Region V fire protectioi agineers recently visited the site to walk down the fire protection modifications already made or conenitted to be made by the Licensee and to review the plant areas where exemptions from Appendix.R had been requested.
'2.0 FUELANDAUXILIARYBUILDINGS, ELEVATIONS 45,61,AND77 FEET (FIREAREA A-4) 2.1 Exemptions Requested Exemptions were requested from Section III.G.2.a to the extent that it requires separation of cables and equipment and associated nonsafety circuits of redundant trains by a fire barrier having a 3-hour rating.
2.2 Discussion The Licensee has stated that the following conditions in Fire Area A-4 do not meet the technical requirements of Section 111.G.2.a: separation of redundant service water booster pump (SWBP) power cables on elevations 61 and 77 feet; separation of redundant diesel fuel oil (DF0) transfer pump power cables on elevations 45, 61, and 77 feet; separation of redundant DF0 transfer pump control cables on elevation 45 feet; separation of redundant centrifugal charging pump (CCP) room cooler power cables on elevations 45 and 61 feet.
The Licensee has also identified other conditions in this fire area which do not meet the technical requirements of Sections III.G.2.b or III.G.2.c of Appendix R to 10 CFR 50. These conditions are the subject of Sections 3.0 and 4.0, respectively.
2.2.1 Description of Fire Area A-4 Fire Area A-4 includes most of elevations 45, 61, and 77 feet of the fuel and auxiliary buildings. Each elevation of Fire Area A-4 is generally adjacent to different fire areas on the elevations above and below, as well as on the same elevation. The following description of the separa-tion of Fire Area A-4 from other fire areas is divided into three main parts (one for each of elevations 45, 61, and 77 feet). Each part is divided into subparts, which describe the separation from other fire areas on the elevation below, the sane elevation, and the elevation above.
Safe shutdown components located in Fire Area A-4 include trains A and B ,
SWBPs and associated power and control cables, trains A and B component '
coolingwater(CCW)pumpsandassociatedpowercables,trainsAandBCCP room cooler power cables, service water (SW) pump control cables, and DF0 transfer pump power and control cables.
l i
g ,
l Various structural steel beams and columns in Fire Area A-4 form a part of fire barriers between Fire Area A-4 and adjacent fire areas. The i Licensee has submitted an engineering evaluation of the thermal response j of these members to fire. The principal section of the evaluation is !
based on FIRES-T3, a well-accepted computer program for modeling the thermal response of structures to fire. The Licensee used this program to calculate the temperature profile of a typical structural steel beam and associated concrete floor slab exposed to fire. These calculations 1 were then used to conservatively estimate the load-bearing capacity of each beam in the. floor-ceiling assemblies. The staff has reviewed the evaluation and concludes that the total methodology is acceptable based upon the similarity of relative stress levels in the unprotected beams.
In some cases, the Licensee indicated that beams will be fireproofed based on the results of the calculations.
2.2.1.1 Fire Area A-4, Elevation 45 Feet Fire Area A-4 on elevation 45 feet is essentially one open area. It is separated from other fire areas (A-1, A-2, and A-3) on elevation 25 feet d by 3-hour fire rated barriers, except for penetrations that are unsealed or penetration seals that are not 3-nour rated between Fire Areas A-4 and A-1, and structural steel supporting the floor of Fire Area A-4 over Fire Areas A-1 and A-3 is not protected. The Licensee has committed to 3 l
provide new or upgraded penetration seals to achieve a 3-hour fire i resistance rating. !
Fire Area A-4 is separated from other fire areas (A-1, A-5, A-8, C-1, E-1, and M-3) on elevation 45 feet and from the exterior of the plant by 3-hour fire rated barriers, except for the nonrated doors and/or nonrated penetration seals that separate Fire Area A-4 from Fire Areas A-1, A-5, and A-8. Nonrated sealant is used in the joints of the precast concrete >
exterior walls. The Licensee has committed to upgrade fire doors and i' penetration seals to a 3-hour fire rating. Few in situ combustibles are in the yard area adjacent to the precast concrete exterior walls. Safe shutdown equipment in Fire Area A-4 is at least 40 feet from the walls.
Fire protection features in Fire Area A-4 on elevation 45 feet consist of !
manual hose stations, portable fire extinguishers, deluge systems actuated by smoke and heat detectors to protect the CCW pumps and the SWBPs, smoke detectors at the CCW heat exchangers, and smoke detectors in the CCW makeup pump area.
The combustible contents of Fire Area A-4 on elevation 45 feet consist of lubricants, electrical cable insulation, small quantities of flammable liquids, and health physics materials. The overall combustible loading is approximately 3,600 Btu per square foot, which produces an equivalent severity of 3 minutes on the ASTM E-119 time-temperature curve.
a
. w g:
", a w - , . : -n ~ , a. . . a < .
'X Ad )
- 5'-
j
~
2.2.1.2 Fire Area A-4, Elevation 61 Feet ,
On. elevation 61' feet . Fire Area A-4 is divided into smaller spaces by nonrated ' partitions with'a single corridor connecting all spaces. It is j
separated from other fire areas (A-1, A-4a, A-5, and A-8)'on.the same elevation by 3-hour fire rated barriers with several exceptions:
Nonrated' doors, fire dampers, and/or penetration seals separate Fire Area A-4 from Fire Areas A-1 and A-8. - Nonrated sealant is used in the joints of the precast concrete exterior walls. No fire barrier exists Lin corridor 203A where Fire Area A-4 joint Fire' Area A-4a. The Licensee has committed to install a water curtain. to separate Fire Areas A-4 and A-4a.-
(see Section 2.2.1.2.1). In addition, the Licensee has committed'to upgrade the doors, dampers, and penetration seals in the barriers separating Fire Area A-4 from Fire Areas A-1 and A-8 to a 3-hour fire rating.
Fire Area A-4 on elevation 61 feet is separated from_ Fire Areas A-4a, A-5, and A-1 on. elevation 77 feet by 3-hour fire rated barriers, except for unprotected electrical and mechanical penetrations between Fire Areas
.A-4a and A-4. The Licensee has committed to upgrade these penetrations to a 3-hour. fire rating.
Fire protection in Fire Area A-4 on elevation 61 feet consists of manual hose stations, portable fire extinguishers, a. heat detector actuated-deluge system at the' residual heat exchanger access, and smoke detectors in the east-west corridor and at the boric acid panel.
On elevation 61 feet, the in situ combustible contents of Fire Area A-4 consist of electrical cable insulation and lubricants, small quantities of charcoal (in a filter), and health physics materials. The overall combustible loading is approximately 12,500 Btu per square foot, which produces-an equivalent severity of about 9 minutes on the ASTM E-119 time-temperature curve.
2.2.1.2.1 Separation of Fire Area A-4 from Iire Area A-4a Fire Area A-4a is only on elevations 61 and 77 feet. On elevation 61 feet, Fire Areas A-4 and A-4a are separated from each other by 3-hour fire rated barriers, except in east-west corridor 203A. The combustibles in this corridor consist of cable trays. The combustible loading in the l
corridor is approximately 25,000 Btu per square foot, which produces an equivalent severity of 19 minutes on the ASTM E-119 time-temperature curve. Fire protection in this corridor consists of portable fire extinguishers, manual hose stations, and one smoke detector. The overall combustible loading in Fire Area A-4a on this level is approximately 16,000 Btu per square foot, which produces an equivalent severity of 12 !
minutes on the ASTM E-119 time-temperature curve.
The Licensee has committed to install a water curtain at column line L in the corridor on elevation 61 feet to coniplete the separation between Fire Areas A-4 and A-4a. The water curtain will consist of 3/8-inch-diameter orifice open sprinklers installed 2 feet from the north and south sides (two sprinklers on each side) of the 42-inch-deep steel beam, which
4 2 -a... - ,- -
crosses the 8-foot-wide' corridor at this location. The water curtain will be automatically actuated by ti,e operation of one of the closed orifice (pilot) automatic sprinklers on either side of the beam. Cable trays and HVAC ducts pass beneath the beam along the length of the corridor. According to the Licensee's design criteria for the water curtain, all of the sprinklers will be above the cable trays and ducts, with the exception of one spinkler, which will be below the lowest cable i tray. The open sprinkler minimum discharge density is designed to be 3 gpm per linear foot of water curtain, with no sprinkler discharging {
1ess than 15 gpm. #
2.2.1.3 Fire Area A-4, Elevation 77 Feet On elevation 77 feet, Fire Area A-4 is divided into smaller spaces by nonrated partitions with a single corridor connecting all spaces. It is i separated from Fire Areas A-4a and A-5 on elevation 61 feet by 3-hour rated barriers and penetration seals. It is also separated from Fire Areas A-1, A-4a, A-5, A-8, C-7, and E-1 on elevation 77 feet by 3-hour rated barriers and penetration seals, except for less than 3-hour rated j doors, duct dampers, and/or penetration seals to Fire Areas A-1, A-4a, '
and A-5. The Licensee has committed to upgrade these features to provide a 3-hour fire separation between Fire Areas A-4 and A-4a on this elevation. Fire Area A-4 is also separated from Fire Areas A-5 and A-6 on elevation 93 feet by 3-hour rated fire barriers and penetration seals, except for the structural steel supporting the floor / ceiling assembly above, which is unprotected. 1
{
l Fire protection in Fire Area A-4 on elevation 77 feet consists of manual i hose stations and portable fire extinguishers. In addition, smoke detectors are provided in the east-west and north-south corridors at the tiger lock tank (used for radwaste solidification) and at the radwaste and boron concentration panels.
On elevation 77 feet, the combustible contents of Fire Area A-4 consist of electrical cable insulation and bealth physics materials. The overall combustible loading is approximately 14,600 Btu per square foot, which produces an equivalent severity of 11 minutes on the ASTM E-119 time-temperature curve.
2.2.2 Discussion of Affected Systems
{
2.2.2.1 Service Water Booster Pump Power Cables l I
i There are four SWBPs on elevation 45 feet; two each in trains A and B. '
One of the four pumps is required for safe shutdown. Trains A and B SWBP power cables are separated by approximately 90 feet of horizontal distance on elevation 61 feet. However, electrical cables in cable trays constitute the major intervening combustibles. The combustible loading in this section of elevation 61 feet east-west corridor 203A is approximately 25,000 Btu per square foot, which produces an equivalant severity of 19 minutes on the ASTM E-119 time-temperature curve.
l l
I p' . ,
. , .n. . , - . . u... ~ . . .
n ~we .
As previously described in Section 2.2.1.2, the Licensee has comitted to install an automatically actuated water curtain at column line L in the east-west corridor to separate Fire Area A-4 from Fire Area A-4a. This is also intended to separate train A power cables from most of train 8 power cables. The Licensee has also comitted to wrap the remaining train B power cables near column B-55 in a 3-hour fire rated enclosure.
On elevation 77 feet, redundant SWBP power cables are separated from each other by approximately 30 feet. The Licensee has comitted to wrap SWBP B power cables on elevation 77 feet in a 3-hour fire rated enclosure, thereby complying with Section III.G.2.a of Appendix R.
The Licensee's exemption request for SWBP power cables on elevation 45 '
feet is discussed in Section 4.2.2.
2.2.2.2 Diesel Fuel Oil Transfer Pump Power Cables Redundant DF0 transfer pump power cables are routed on elevations 45, 61, and 77 feet. On elevation 45 feet, trains A and B cables are separated by 3 feet. The Licensee has committed to wrap DF0 transfer pump B power cables in a 3-hour fire rated enclosure, thereby complying with Section III.G.2.a of Appendix R.
Onelevation61 feet,someoftheredundantcables(nearcolumnB-55)are separated by 4 feet, while the remaining cables are separated by approxi-mately 90 feet. Intervening combustibles consist of cables in cable trays. The combustible loading in this section of the floor level (rooms 190 and 254) is approximately 23,000 Btu per square foot, which produces an equivalent severity of 17 minutes on the ASTM E-119 time-temperature curve. The fire protection for this area is as described in Section 2.2.1.2. The Licensee has comitted to wrap the train B power cables located near column B-55 in a 3-hour fire rated enclosure, thereby complying with Section III.G.2.a of Appendix R. Separation of the remaining power cables will be accomplished by the installation of the previously described water curtain.
On elevation 77 feet, trains A and B cables are separated by 28 feet.
The Licensee has comitted to wrap train 8 power cables in a 3-hour fire ,
rated enclosure, thereby complying with Section III.G.2.a of Appendix R. )
i 2.2.2.3 Diesel Fuel Oil Transfer Pump Control Cables l Redundant DF0 transfer pump control cables routed on elevation 45 feet are separated from each other by 4 feet. The Licensee has comitted to wrap DF0 transfer pump B control cables in a 3-hour fire rated enclosure, thereby complying with Section III.G.2.a of Appendix R.
2.2.2.4 Centrifugal Charging Pump Room Cooler Power Cables Redundant CCP room cooler power cables are routed only on elevations 45 and 61 feet. Redundant cable trains are separated from each other by over 20 feet of horizontal distance on each level, but intervening combustibles in the form of cables in cable trays are present. The Licensee has comitted to relocate train B power cables so that they are independent of Fire Area A-4 on elevations 45 and 61 feet, thereby complying with Section III.G.2.a of Appendix R to 10 CFR 50.
i
swe . . ,;. . ; ~ < ~ , * - - - ~+' !*Nt N*s 'T*A IM Y' "' ""
2.3 Evaluation The fire protection provided for the following systems in Fire Area A-4 complies with the technical requirements of Section Ill.G.2.a because redundant trains of cables are separated by. fire barriers having a 3-hour rating: SWBP power cables on elevations 61 (in part) and 77 feet; DF0 transfer pump power. cables on elevations 45, 61 (in part), and 77 feet; DF0 transfer pump control cables on elevation'45 feet, and CCP room cooler power cables on elevations 45 and 61 feet. This has been accomplished by the installed fire protection and the Licensee's commitment to wrap trains B of the above-listed systerns in a 3-hour fire rated enclosure.
The fire protection provided for the SWBP power cables and the DF0 transfer pump power cables on elevation 61 feet complies with the technical require-ments of Section III.G.2.a of' Appendix R because redundant trains of cables and equipment and associated nonsafety circuits are separated by fire barriers having a 3-hour rating. The Licensee has consnitted to install a water curtain in east-west corridor 203A on elevation 61 feet, !
which would provide an effective fire barrier between Fire Areas A-4 and A-4a and between the systems described above. ,
With the installed fire protection features in conjunction with consnitted modifications, the staff has reasonable assurance that a fire originating in the above-described sections of Fire Area A-4 will not prevent the plant from safely shutting down.
2.4 Conclusion Based on the above evaluation, the staff has concluded that the existing fire protection features combined with the Licensee's proposed modifica-tions meet the technical requirements of Section III.G.2.a for the following cables: SWBP power cables on elevation 61 and 77 feet; DF0 transfer pump power cables on elevations 45, 61 and 77 feet; DF0 transfer pump control cables on elevation 45 feet; and CCP room cooler power cables on elevations 45 and 61 feet. Therefore, an exemption request for the above cables is not required.
The staff's acceptance regarding unprotected structural steel is described in Section 2.2.1.
3.0 FUEL AUXILIARY BUILDINGS, ELEVATION 45, 61, AND 77 FEET (FIRE AREA A-4) 3.1 Exemptions Requested Exemptions were requested from Section III.G.2.b to the extent that it requires separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards and to the extent that it requires fire detectors and an automatic fire suppression system to be installed in the fire area.
._______-_-______L
1
,s..
]
l L '
(. ~9-
}
l 3.2 Di_scussion i i
The Licensee has stated that the following conditions in Fire Area A-4 do .1 not meet the technical requirements of Section III.G.2.b: CCW pumps and i SWBPs on elevation 45 feet; SWBP control cablet on elevations 61 and 77 feet; SW pump control cables on elevations 45, 63, and 77 feet; and DF0 transfer pump control cables on elevations 61 and 77 feet.
3.2.1 . Description of Safety-Related Equipment 3.2.1.1 Component Cooling Water Pumps There are three CCW pumps on elevation 45 feet designated as A, B, and C.
Hot shutdown can be achieved with any one of these pumps. Two pumps are required for cooldown. CCW pump A is located approximately 14 feet west of pump B, and CCW pump C is located approximately 24 feet northwest of CCW pump A.
Intervening' combustibles between these three pumps consist of cables in I trays routed near the ceiling and approximately I gallon of lubricating oil in each pump. The combustible loading in this location (room 228) is approximately 3,000 Btu per square foot, which produces ar. equivalent fire severity of approximately 2. minutes on the ASTM E-119 time-temperature curve. Power cables for each pump are routed to the level below through a floor penetration next to each of the pumps. The fire protection for the pumps is as described in Section 2.2.1.1.
3.2.1.2 Service Water Booster Pumps I SWBPs A, B, C, and D are located on elevation 45 feet, north and west of i CCW pump C. SWBPs A and C are designated as train A pumps. SWBPs B and D are designated as train B pumps. Safe shutdown can be achieved using any one of the four pumps. The train A pumps are located approximately 15 feet west of the train B pumps.
Intervening combustibles between these pumps consist of cables in trays routed near the ceiling and lubricating oil in the pumps. The combust-ible loading in this area (room 164) is approximately 1,900 Btu per square foot, which produces an equivalent severity of approximately 1-1/2 minutes on the ASTM E-119 time-temperature curve. The fire protection in this area is as described in Section 2.2.1.1.
3.2.1.3 Service Water Booster Pump Control Cables Control cables for all four SWBPs are routed on elevations 45, 61, and 77 feet. An exemption request for the SWBP control cables on elevation 45 feet is addressed in Section 4.2.
l
_______.____d
On elevation 61 feet, the redundant trains are separated by 9 feet. .
Intervening combustibles between these cables consist of cables in trays. !
The combustible loading in this location (room 254) is approximately 1 24,000 Btu per square foot, which produces an equivalent severity of approximately 18 minutes on the ASTM E-119 time-temperature curve. The fire protection for this area is as described in Section 2.2.1.2.
On elevation 77 feet, the redundant trains are separated by approximately 28 feet. Intervening combustibles consist of cables in trays. The ,
combustible loading in this location.(room 270) is approximately 12,000 Btu per square foot, which produces an equivalent severity of approximately 9 minutes on the ASTM E-119 time-temperature curve. The fire protection for this area is as described in Section 2.2.1.3.
The Licensee has comitted to install decouple switches in the control .
building switchgear room (Fire Area C-2). The decouple switches will permit control of train B SWPBs from an emergency control station independent of Fire Area A-4. Section 3.6.3.4 of the Licensee's Appendix R review indicates that this does not require removal and replacement of fuses.
3.2.1.4 Service Water Pump Control Cables l Control cables for all three SW pumps (A, B, and C) are routed on '
elevations 45, 61, and 77 feet. Each SW pump is designed to provide 100 percent of the service water requirement during normal operation and 100 percent of the requirements for each train for two-train operation during ,
abnormal conditions or normal plant cooldown. SW pumps A and B are i directly connected to their respective trains. SW pump C can be connected to either train A or B and can be powered from the bus for either train A or B through a manually operated transfer switch as described in Section 3.5.2.2.7 of the Licensee's submittal.
On elevation 45 feet, the redundant trains are separated by 10 feet. l Intervening combustibles consist of cables in trays. The combustible !
loading in this location (rooms 234, 228, and 164) is approximately 1,600 I Btu per square foot, which produces an equivalent severity of approxi- I' mately 1 minute on the ASTM E-119 time-temperature curve. The fire protection for this area was previously described in Section 2.2.1.1.
l On elevation 61 feet, the redundant trains are separated by 35 feet. !
Intervening combustibles consist of cables in trays. The combustible l loading in this location (rooms 253, 190, and 203A) is approximately l 14,500 Btu per square foot, which produces an equivalent severity of approximately 11 minutes on the ASTM E-119 time-temperature curve. The fire protection for this area was previously described in Section 2.2.1.2. \
l On elevation 77 feet, the redundant trains are separated by 48 feet. I Intervening combustibles consist of cables in trays. The combustible i
loading in this location (room 269) is approximately 12,000 Btu per square foot, which produces an equivalent severity of approximately 9 minutes on the ASTM E-119 time-temperature curve. The fire protection )
i for this area was previously described in Section 2.2.1.3. l 1
i l
- ( w, p an x - - e + "
-~"
- M W 'NM *
-L11 -
1 1
The Licensee has committed to install decouple switches in the control
. building _ switchgear room (Fire Area C-2)', The decouple switches will permit control of train B SW pu ps from an emergency control station independent of Fire Area A-4.R ection 3.6.3.4 of the Licensee's .
submittal indicates that this operation does not require removal and .!
replacement of fuses.
{
, 3.2.1.5 Diesel Fuel Oil Transfer Pump Control Cables Control cables for DF0 tranrfer pumps A and B are' routed on elsvations ;k 45, 61, and 77 feet. Each' pump is designed to provide 100 percent of the '
DF0 requirement under all conditions of plant operation. DF0 pumps A and-B are directly connected to their respective trains'and can be connected into either train A or B and can be powered from the bus for either train A or B through a manually operated transfer switch. The exemption request for the cables on elevation 45 feet is discussed in Section
- 2. 2. 2.3. -
l On elevation 61. feet, the redundant trains are separated by 8 feet.
Intervening combustibles consist of cables'in trays. The combustible
_ loading in this location (room 254) is approximately 24,000 Btu per square foot,'which produces an equivalent severity of approximately 18 l minutes on the ASTM E-119 time-temperature curve. Fire protection for this: location was previously described in Section 2.2.1.2.
On elevation 77 feet, the redundant trains are separated by 28 feet. .l Intervening combustibles consist of cables in trays.- The combustible loading in this location-(room 270) is approximately 12,000 Btu per square foot, which produces an equivalent severity of approximately 9 minutes on the ASTM E-119 time-temperature curve. The fire protection for this location was previously described in Section 2.2.1.3.
The Licensee has committed to install a decouple switch in the control building switchgear room (Fire Area C-2). The decouple switch will permit control of the train 8 DF0 transfer pump from an emergency control station independent of Fire Area A-4 Section 3.6.3.4 of the Licensee's submittal indicates that this operation may require fuse removal and replacement, which is pemissible for long-term hot shutdown equipment.
3.3 Evaluation The fire protection in this fire area does not comply with the technical requirements of Section III.G.2.b of Appendix R because redundant trains of cables and equipment and associated nonsafety circuits of redundant trains are not separated by a horizontal distance of more than 20 feet free of intervening combustibles or fire hazards and because fire ,
i detectors and an automatic fire suppression system are not installed in i the fire area. {
1 The staff was concerned that because redundant CCW pumps, SWPBs and their j control cables, SW pump control cables, and DF0 transfer pump control i cables were not separated by at least 20 feet of horizontal distance free J of intervening combustible and fire hazards, a path may exist for the l spread of fire between redundant safe shutdown systems. Also, the lack j
o ,
3,, , . _, , . < . __ , -, . c - - 'M A,AWAMU <
of fixed sup)ression systems and fire detectors throughout this fire area may permit tle fire to spread and result in the loss of safe shutdown capability. However, because of the light combustible loading in this fire area, the staff does not expect a fire of significant duration or magnitude to occur.
Intervening combustibles in the form of cables in trays could provide a path for the spread of fire between redundant safe shutdown systems.
However, cable quantities along these paths are small. In addition, the intervening combustibles at the CCW pumps and SWBPs are routed only at the ceiling level (well above the pumps) and each pump is protected by an individual deluge system.
If a fire were to occur near the subject equipment or cables, it would i develop slowly with initial low heat release and siow rise in room temperature. The fire would be detected by one of the fire detection systems before it became fully developed. The detector alarms would annunciate in the control room. A fire at the CCW pumps or the SWBPs would cause actuation of the deluge systems at the affected pumps. The fire brigade would also be dispatched to extinguish the fire.
In addition, the Licensee has committed to install decouple switches for the train B SWBPs, SW pump, and DF0 transfer pump to permit control of these pumps from an emergency control station independent of this fire area. The Licensee will also implement procedures to decouple the i control circuits for the affected pumps in the event of a fire in this ;
fire area. !
Despite the presence of intervening combustibles between redundant safe shutdown systems in this fire area and the lack of fire detectors and an automatic fire suppression system throughout the area, there is reason-able assurance that a fire will not result in the loss of safe shutdown capability. Therefore, the staff finds that separating cables and equipment of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards in Fire Area A-4 would not significantly increase the level of fire protection.
3.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed modifications provide an acceptable level of protection. Therefore, the exemptions can be granted.
4.0 FUEL AND AUXILIARY BUILDINGS, ELEVATION 45 FEET (FIRE AREA A-4) 4.1 Exemptions Requested Exemptions were requested from Section III.G.2.c to the extent that it requires enclosure of cable and equipment and associated nonsafety circuits of one redundant train in a fire barrier having a 1-hour rating and to the extent that it requires installation of fire detectors and an automatic fire suppression system in the fire area.
t
- , .n ,
p.c - .: . ,. .- s. . -- . x. . . . . - . a.w.wa%, k&
L
.13 -
4.2 Discussion The Licensee has stated that the following conditions in this fire area do. not meet the technical requirements of Section III.G.2.c: CCW pump power cables and.SWBP power and control cables on elevation 45 feet.
4.2.1 Component Cooling Water Pump Power Cables On elevation 45 feet, the redundant trains are separated by 5 feet.
Intervening combustibles consist of cables in-trays. The combustible load-ing in this location (room 228) is approximately 3,000 Btu per square foot, which produces an equivalent severity of.approximately 2 minutes on the ASTM E-119 time-temperature curve. The Licensee has committed to wrap train B of these cables in a 1-hour fire rated barrier. Fire 1
i protection in this room consists of an automatic deluge system actuated by smoke detectors.
4.2.2 Service Water Booster Pump Power Cables On elevation 45 feet, the redundant trains are separated by 9 feet.
Intervening combustibles consist of cables in trays. The combustible loading in this location (room 164) is approximately 2,000 Btu per square foot, wnich produces an equivalent severity of approximately 2 minutes on the ASTM E-119 time-temperature curve. The Licensee has comitted to wrap train B of these cables in a 1-hour fire rated barrier. The fire protection in this room consists of an automatic deluge system actuated by smoke detectors.
4.2.3 Service Water Booster Pump Control Ce51es On elevation 45 feet, the redundant trains are separated by 9 feet.
Intervening combustibles consist of cables in trays. The combustible loading.in th's location (room 164) is approximately 2,000 Btu per square foot, which ptoduces an equivalent severity of approximately 2 minutes on the ASTM E-119 time-temperature curve. The Licensee has comitted to wrap train B of these cables in a 1-hour fire rated barrier. The fire protection irt this room consists of an automatic deluge system actuated by smoke detectors.
4.3 Evaluation The fire protection in this fire area does not comply with the technical .
requirements of Section III.G.2.c of Appendix R to 10 CFR 50 because j fire detectors and an automatic fire suppression system have not been J installed throughout the fire area. l I
There was concern that the intervening combustibles and fire hazards near the CCW pump power cables and the SWBP power and control cables may create a path for the spread of fire between redundant safe shutdown systems and that the lack of fixed suppression systems and fire detectors throughout the area may permit the fire to continue and result in the loss of safe shutdown capability. However, because of the light combustible loading in this location, it is not expected that a fire of significant duration or magnitude would occur.
l . " .-
i
,. ,,, 'C
. . ,. - b *.e - - ~ < -
~ ~4 5S - - ~ ~ ' ' - -
L
- 14 - '
1 i
Intervening combustibles in the form of cables in trays provide a path I for the spread of fire between redundant safe shutdown systems. However, cable quantities along these paths are small and the Licensee has committed to prap the train B cables of each of these systems in a 1-hour fire rated I
barrier.
If a fire were to occur, it would develop slowly with initial low heat release and slow rise in room temperature. The light combustible loading (2-minute equivalent severity) and the 1-hour fire barrier wraps on train 8 of the CCW pump power cables and the SWBP power and control cables pro-vide reasonable assurance that a fire in this area would not result in the loss of redundant trains of CCW pumps or SWBPs. In addition, despite the ,
lack of fire detectors and an automatic fire suppression system through- l out the fire area, the fire should be detected by one of the installed fire detection systems, which would activate the deluge systems in the room con-taining the equipment. The detector alarm would annunciate in the control room and the fire brigade would be dispatched to extinguish the fire.
Despite the presence of intervening combustibles between redundant safe f shutdown systems in this fire area, there is reasonable assurance that a fire will not result in the loss of safe shutdown capability. Therefore, the staff finds that installing fire detectors and an automatic fire sup-pression system throughout the fire area would not significantly increase the level of fire protection in these locations. ,
1 4.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed modifications provide an acceptable level of protection. Therefore, the exemptions should be granted.
5.0 ELECTRICAL PENETRATION AREA (FIRE AREA E-1) 5.1 Exemptions Requested Exemptions were requested from Section III.G.2.b to the extent that it requires separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.
5.2 Discussion The Licensee has stated that the following condition in Fire Area E-1 does not meet the technical requirements of Section III.G.2.b of Appendix R to 10 CFR 50: Redundant trains of cables and equipment are not separated by a horizontal distance of more than 20 feet free of intervening combustibles and fire hazards.
The redundant cable trains include the following safe shutdown systems:
Process monitoring instrumentation cables, neutron source range preamplifiers, containment air cooler (CAC) cables, isolation valves for secondary inventory control, and DF0 transfer pump control cables. The process monitoring instrumentation includes RCS pressure and temperature.
.w a ,
l: '
.. -- . .- -)
a 5.2.1 Description of Fire Area E-1 l
Fire Area E-1 consists of the electrical penetration area, the main steam-support structure (MSSS) and the remainder of the open area between the containment and the control building, auxiliary and fuel buildings, and turbine building at elevations 45 feet through 117 feet. Fire Area E-1 has no roof. A concrete slab at elevation 93 feet protects safe shutdown cables from direct exposure to the weather, but does not ' completely close off the space. Fire Area E-1 is separated from adjacent Fire Areas A-6, R-1, and T-1 by 3-hour fire rated barriers, except for the boundaries at Fire Area A-6 (auxiliary building, elevation 93 feet), Fire Area T-1 (turbine building), and Fire Area R-1 (containment) are not entirely 3-hour rated.
Fire Area E-1 is divided into two parts by a 3-hour fire rated masonry shield wall, which includes the electrical penetration area adjacent to -
the reactor containment (Fire Area R-1) and the remainder of the fire ,
area. . The shield wall extends from elevation 45 feet to elevation 83 feet. There is a 10-foot-high opening between the top of this wall and the concrete slab at elevation 93 feet and 2-inch-wide gaps between the ,
shield wall and the containment wall.
1 The opening and gaps are not deviations from Section III.G of Appendix R to 10 CFR 50 since the wall does not constitute a boundary between fire areas. The main purpose of the wall is to provide shielding from potential radiation streaming through the penetration assemblies. It also serves as an effective means of separating combustibles in the main fire area (E-1) from vertical cable raceways near the containment penetra-tions. These cable raceways, which pass directly below the 93-foot elevation deck and through the overhead opening are protected on both sides of the wall with a water spray system.
The combustibles in Fire Area E-1 consist primarily of cable insulation.
The combustible loading inside of the shield wall is 89,200 Btu per square foot, which produces an equivalent severity of approximately 67 minutes on the ASTM E-119 time-temperature curve. The combustible loading outside of the shield wall is 83,200 Btu per square foot, which produces an equivalent severity of approximately 63 minutes on the ASTM E-119 time-temperature curve. There is a negligibit- combustible loading in the MSSS.
Redundant trains of cables are generally routed vertically inside of the shield wall and horizontally outside of the shield wall. In general, the routing of electrical cables for process monitoring instruments and the CACs extend from the containment penetrations at elevations 53 to 74 feet, rise vertically in trays or conduit along the shield wall, cross over the shield wall (top of the wall is at elevation 83 feet), and run horizontally into the control building, as shown in Figures 3-23 and 3-24 of the Licensee's submittal. An exception is the steam generator pressure cables, which are routed independent of the containment in embedded conduit, then into the vertical trays inside of the shield wall. '
- o ,
, TJ A
%.: w n a;. +,w & n
'"~. N
, ~ ~ ~
_- [" ~
- r'N#E 7 ]
The subject cables of redundant A and B channels are. separa'ted within the i shield wall by a horizontal distance of more.than 20 feet (Mth interve9-ing combustibles in the form of cables in trays), and outside\bf the .
shield wall by a vertical distance of 13 feet (free air sphe and no ' #
other trays in between). '
7
< ; r ;
Separation between redundant trains of DF0 transfer pump control k.bles 'I ' !
is about 2 feet. These cables are routed in condyit and'the Licruce has i committed to provide a decouple switch for the train B pump as ,part of !
the alternative shutdown capability provided for Fire Areas C-7 and C-11. !
This will allow the pump to be controlled independentlysof FWe Area .E-L l No fuse pulling is necessary for the decouple switch. ', )
5.2.2 Separation from Adjacent Fire Areas y e I The Licensee has provided descriptions of the barrier lepkating Fire
~
Area E-1 from adjacent Fire Areas A-6, R-1, and T-1. U.i l 5.2.2.1 Fire Area A-6 sefe '
Fire Area shutdown A-6 but cables, does maynot havecontain significantany safecombustil transient shutdown . equipment oke l Combustibles in this fire area include cable insulation, charco'al filter '
media, health physics materials, and compressed hydrogen g u., The <l. 4 g 1g combustible loading is approximately 15,000 Btu per squ re foot, wh ch I i
produces an equivalent fire severity of 11 minutes on the ASTM E-11 time-temperature curve.
1
\.>/
I A large section of Fire Area A-6/E-1 boundary, above slevation 93 feet (approximately 55 feet x 24 feet), is a nonrated metal-faced wall. A HVAC duct penetrates this wall without a fire damper. Safe shutdown ;
cables in Fire Area E-1 are located under elevation 92 feet,10 inches '
slab, at least 20 feet horizontally away from the metal wall, and are protected by an automatic water spray system. The metal wall is,48 feet ,
above the grade level slab in Fire Area E-1 and there are no intersning '
combustibles in the space between the wall and the Lafe shutdown cables * <
except for one 18-inch-wide cable tray. This tray is 15 feet below the J metal wall and is covered with a metal cover in the area where it could ,(
be exposed to burning debris from Fire Area A-6. Therefore, propaga- , --
tion of a fire from Fire Area A-6 to Fire Area E-1 safe shutdown cables is not likely. Since Fire Area A-6 does not contain safe shutdown components, a fire in Fire Area E-1 need not be considered for its effect I l on Fire Area A-6. Therefore, it is deemed that Fire Area A-6/E-1 s l
boundary provides adequate fire protection for the safe shutdown cables in Fire Area E-1. {'
i i p
Justification of the nonrated HVAC opening through Fire Area A-6/E ;1 k;
boundary follows the same reasoning as the nonrated wall. The HVAC doct- '
is at least 40 feet away from the safe shutdown cables in Fire Area E-1. ' 1 1
Providing a fire rated damper would not enhance fire protection for the - I safe shutdown cables in Fire Area E-1. >
t
3
,, ..e') '
'5 1 ( , ;
4 ,
.s
- j. ; 3, 7' ,, . . _ d L . - . cs J h \ !;
{
3
't
.l
' ' ' i-, . !
5.2.2.2 -Fire Area R-1 / 'g ) V i
(: ,
Fire Area R-1 contains redundant safe shutdown cables and equip- 1 ment. The concrete ' wall separating Fire Areas E-1 and R-1 is *i-hour fire
]
rated with the exception g>f s, some untested electr/, cal penetrations. ;
- y. '
/
The average combustible loading in Fire Area R-1 is approximately 15,000-Btu per square foot, which produces an equivalent fire severity of approximately 12 minutes in the ASTM E-119 time-temperature curve, m The electrical penetration assemblies in the containment wall are constructed of_ structural steel and are securely anchored to the contain-ment wall. There are no gaps and air transfer through the assemblies.
Cable module penetrations in the flange (.over are sealed with General Electric RTV 560 silicone rubber, which is flame resistant and rated at 500'F for continuous operation.. The penetration assemblies are qualified for the Integrated Leak Rate Test pressure of 60 psi. In the case of a fire near the penetration assemblies, the steel would retain a minimum
- $ yield strength of about 5 ksi, even if the steel temperature were to rise
, as high as 1300 F. This capacity is more than the strength required to support the penetration assembly. In addition, the penetration
(]!!f '
assemblies and penetrating cable modules are protected on. Fire Area 0-!
4 \ side by a water spray system. It is deemed that the penetration assem-
/ ; ', blies will function as a barrier equivalent to a 3-hour fire rated
< <' barrier. Upgrading the penetration assembly seals to a 3-hour rating
/ would not enhance the fire protection provided by the boundary.
' ' - i 5.2.2.3 F_ir_ej.rea T-1 h <
Fire Area T-1 is the general turbine building area and contains Fire jd Areas T-2 through T-8. Fire Area T-1 contains no safe shutdown cables or
(, equipment, except in two locations:
/ '
,. 'a . Main feed pump B area on elevation 45 feet. This pump is protected by an automatic deluge sprinkler system. The pump is approximately
, g\ 45 feet from the wall, separating Fire Areas T-1 and E-1. Fire
- c Areas T-2, T-3, and T-4 are between main feed pump B and the wall.
'\< b.
Load center area on elevation 69 feet. This area is located at the
/
north end of the turbine building, west of the control building and
, there is approximately a 200-foot horizontal distance from the wall separating Fire Areas T-1 and E 1..
", Combustibles in the turbine building, elevation 45 feet, include cable i insulation, lube oil, and hydrogen. The combustible loading is approxi-mately 24,000 Btu per square foot, which produces an equivalent fire severity of Wg minutes on the ASTM E-119 time-temperature curve.
Combustibles in the turbine building, elevation 69 feet, include cable '
, insulation, lube oil, and battery casings. The combustible loading is
/ .approximately 80,000 7tu per square foot, which produces an equivalent 1
fire severity of 60 minutes on the ASTM E-119 time-temperature curve.
A \
9 e
r . - _ _ _ _ _ - - _ _ _ _ _ -
,--- z J ;
, o . .' y'
/ . * ~
q; :f ,
e sThe barrier between Fire Areas E-1 and T-1 consists of precast panels with earat.ed sealant, nonrated metal walls, and a partial 3-hour fire rated concrete wall with some unsealed penetrations. As shown in Figures 2-21 and 2-22 of the Licensee's submittal, the precast section of the wail will be upgraded by grouting panel seals, installing rated penetra-tion seals, and installing a labeled door. The metal section of the wall will be protected with an automatic water suppression system to provide cooling and structural protection of the wall. The piping and detection E system will be on Fire Area T-1 side of the wall ar.o the system will discharge water directly onto the structural steer and metal siding to prevsnt a fire in Fire Area T-1 from propagating to Mde Area E-1. The main steam piping and the feedwater piping penetration openings in the 3-hour rated concrete wall are impractical to seal. The combustible Icading in Fire Area E-1 near these penetrations is insignificant and thee fs a lack of combustible continuity for propagation of fire from cre area through these penetrations to the other area.
. 5.2.3 Fire Protection in Fire Area E-1 Nreprotection in Fire Area E-1 consists of an open-head directional water spray system with a minimum spray density of 0.3 gpm per square foot of tray surface area outside of the shield wall and 0.15 gpm per square foot of tray surface inside of the shield wall. The spray nozzles are distributed on both vertical and horizontal branch lines so that water spray will cover the projected plane arco of the top and bottom of j each cable tray and supporting structures. Each suppression zone has the
! provision for manual actuation vie a pull station located at the turbine buildirg, elevation 45 feet, near. hose station 15. In addition, each suppression zone is automatically' actuated by two cross-zoned detection e circufts. Receipt of an alarm fr4iut from one of the detection circuits
/ initiates a 2-minute time dehy relay. If at the end of 2 minutes both detector circuits are in alarm, the associated suppression system is automatically actuateca Both ionization and photoelectric-type smoke detectors are installes to provide early detectiun and suppression in case of fire. Fire detectors are placed above safety-related trays.
Manual fire suppression capability consists of portable fire extinguish-ers at elevation 45 fact.
Radiant energy shields are installed inside of the shield wall vertical runs of cable trays. The cable trays outside of the shield wall are 28 to 42 feet above the floor level.
5.2.4 Modifications '
In addition to the modifications described in Section 5.2.2.3, the Licensee has committed to nake the following additional modifications:
o One channel of process monitoring instrumentation cables will be protecte'd by a 1-hour rated fire barrier :inside of the shield wall.
l These include stem generator pressure and level, pressurizer level, and RCS pressure and temperature., which are all routed in a single cable tray.
/
u . _ _ _ _ _ _ - . _ . - - _ - _ _ _ _ _ _ _ - - - - - - - - - _ - _ - - _ - - - - - - - - - - - - - - - - - - - - - -- - - - - - - --- - - - - - - - - - - - - - - - - - - - - - - -
--c .. ,. ..
_ . - .,s . , . .w.- . . . -
-w"4 % l-4 9 o One channel of cables for a new neutron source range monitor will be protected by a 1-hour rated fire barrier inside of the shield wall. 1 o One train of power cables for the CACs will be protected by a 1-hour rated fire barrier inside of the shield wall.
o The 2-minute time delay for the suppression system actuation will be removed.
5.3 . Evaluation The fire protection in this fire area does not comply with the technical requirements of Section III.G.2.b of Appendix R to 10 CFR 50 because
. cables and equipment and associated nonsafety circuits of redundant trains are not separated by a horizontal distance of more than 20 feet free of intervening combustibles or fire hazards.
There was concern that the separation of redundant trains of cables by less than 20 feet of horizontal distance (even if the separation distance exceeds' 20 feet) and the presence of intervening combustibles between redundant trains of cables may create a path for the spread of fire between redundant safe shutdown systems.
If a fire were to occur outside of the shield wall in Fire Area E-1, it is expected to develop slowly with a low initial heat release and to be detected by the detection system, which would annunciate in the control room to dispatch the plant fire brigade to extinguish the fire. The vertical separation between redundant trains of cables, 0.3 gpm per i square foot deluge system discharge density, and a minimum 28-foot cable tray height above the floor of this area will limit the maximum temperatures felt by the upper trays. In addition, the openness of this fire area will virtually eliminate the possibility of a buildup of hot gases at the ceiling. Despite the presence of intervening combustibles between redundant safe shutdowr. systems in this fire area, there is reasonable assurance that a fire will not result in the loss of safe shutdown capability.
If a fire were to occur inside of the shield wall (in Fire Area E-1), it is expected to develop at a moderate rate because of the mainly vertical orientation of the cable trays. Temperature rise in the area would be low to moderate because of the openings to the exterior at the top of the-shield wall. It is expected that a fire would be detected by the installed fire detection system, which would annunciate in the control room to dispatch the plant fire brigade to extinguish the fire. The Licensee's conrnitted modifications for protecting process monitoring instrumentation cables, neutron source range monitor cables, and CAC power cables, as well as the new DF0 transfer pump decouple switch and the installed automatic deluge system provide reasonable assurance that a fire inside of the shield wall will not result in the loss of safe shutdown capability.
Therefore, the staff finds that separating cables and equipment of redundant trains by a horizontal distance of more than 20 feet with no
n V ' '
i i
intervening combustibles or fire hazards in the fire area would not significantly increase the level of fire protection in this location.
5.4 Conclusion Based on the above evaluation, the sh.ff concludes that the existing fire protection features combined with the proposed modifications provide an acceptable level of protection. Therefore, the exemptions can be granted.
6.0 TURBINE BUILDING, GENERAL AREA (FIRE AREA T-1) 6.1 Exemptions Requested Exemptions were requested from Section 111.G.2.b of Appendix R to 10 CFR 50 to the extent that it requires separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards and to the extent that it requires fire detectors and an automatic fire sup-pression system to be installed in the fire area.
6.2 Discussion Fire Area T-1 includes the general area of the turbine building at the 45 , 69 , and 93-foot elevations. Fire Area T-1 is separated from other fire areas containing redundant safe shutdown equipment. In particular, Fire Area T-1 is separated from the two emergency diesel generator rooms (Fire Areas T-5 and T-6) by 3-hour fire rated barriers.
The Licensee has stated that the following conditions do not meet the i
technical requirements of Section III.G.2.b of Appendix R to 10 CFR 50:
separation between the normal and alternate air intakes for redundant emergency diesel generators and separation between the train A cables and the normal air intake for the train B emergency diesel generator.
The normal air intakes for the two emergency diesel generators are located on elevation 45 feet, next to each other in the corridor along the east side of the train B emergency diesel generator room. An alternate intake for the train A emergency diesel generator is on the south side of the room.
The alternate intake is provided with an automatically actuated motor oper-ated damper, which is to function in the event of a fire in the train B emergency diesel generator room. The air intake for emergency diesel l
generator A is separated from the motor operated damper by over 80 feet of horizontal distance around the perimeter of the diesel generator rooms.
The train A electrical switchgear room (Fire Area T-8) is on elevation 69 feet, directly above the two energency diesel generator rooms. Elevations 69 and 45 feet of Fire Area T-1 are connected to each other by open stair-ways and other floor penetrations.
Cables for nearly all train A safe shutdown equipment are routed on elevation 69 feet from the train A electrical switchgear room to the
- ~ w. a > . . mn y . - ' - - + $
control building. The cable routing is directly above the corridor containing the normal emergency diesel generator ventilation intakes.
Train B safe shutdown cables are routed independently of Fire Area T-1. i l
Combustibles on elevation 45 feet of Fire Area T-1 consist of cable insulation, lubricants, and hydrogen in the hydrogen seal oil tank. The combustible loading in Fire Area T-1 is approximately 24,000 Btu per square foot, which produces an equivalent severity of 18 minutes on the ASTM E-119 time-temperature curve. Fire protection in this area consists :
of portable fire extinguishers, manual hose stations, sprinkler and deluge systems, and heat and smoke detectors located only at concentra-tions of combustibles and fire hazards.
The combustibles above the hallway on elevation 69 feet are the train A cables. The combustible loading in this area is approximately 80,000 Btu per square foot, which produces an equivalent severity of 60 minutes on the ASTM E-119 time-temperature curve. Fire protection in this section of the turbine building consists of portable extinguishers, a manual hose station, and smoke detectors.
The Licensee has committed to install an automatic sprinkler system under elevation 69 feet floor slab and to upgrade the floor slab to a 3-hour rated fire barrier.
6.3 Evaluation The fire protection in this fire area does not comply with the technical requirements of Section III.G.2.b of Appendix R because cables and equipment and associated nonsafety circuits of redundant trains are not separated by a horizontal distance of more than 20 feet free of interven-ing combustibles or fire hazards and because fire detectors and an automatic fire suppression system are not installed in the fire area.
There was concern that the intervening combustibles and fire hazards (mainly cable insulation) between the normal and alternate air intakes for the emergency diesel generators and between train A safe shutdown cables and the normal intake for the train B emergency diesel generator may create a path for the spread of fire between redundant safe shutdown systems. There was also concern that the lack of fixed suppression systems and fire detectors may permit the fire to continue and result in the loss of safe shutdown capability.
i Because of the nature of the combustibles (non-IEEE Std 363 qualified !
cable insulation), if a fire were to occur in Fire Area T-1 near the subject systems, the staff expects it to develop slowly with low initial heat release and rise in room temperature. It is expected that the fire detection and suppression systems (which are presently installed or will be installed) would detect the fire and annunciate in the control room.
The control room operators would then dispatch the fire brigade to complete extinguishment of the fire. Should the fire continue, it is not expected that it would propagate quickly between redundant safe shutdown systems. Also, the approximately 23-foot-high ceiling in the corridor in front of the emergency diesel generator room and the large open spaces on this level of Fire Area T-1 should slow the development of a heated gas l
g 84 t
,, ._. - ' ~ - ~
.\1*'p'- *
?
layer at the ceiling and, thereby, reduce the threat to the redundant systems.
Despite the presence of intervening combustibles between redundant safe shutdown systems in this fire area, there is reasonable assurance that a fire would not result in the loss of safe shutdown capability. Therefore, the staff finds that separating cables and equipment of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards would ne- significantly increase the level of fire protec-tion in these locations 6.4 Conclusion Based on above evaluation, the staff concludes that the above-described fire protection provides an acceptable level of protection. Therefore, the exemptions should be granted.
7.0 YARD AREA (FIRE AREA Y-1) 7.1 Exemptions Requested Exemptions were requested from the technical requirements of Section III.G.2.b of Appendix R to 10 CFR 50 to the extent that it requires separa-tion of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards and to the extent that it requires fire detec-tors and an automatic fire suppression system to be installed throughout the fire area.
7.2 Discussion The yard area (Fire Area Y-1) is the designation for all non-enclosed areas external to the plant proper _ It, therefore, is adjacent to all plant buildings and to many plant fire areas.
The only safe shutdown equipment present in Fire Area Y-1 are the two 40,000-gallon DF0 storage tanks. The tanks are approximately 50 feet J north of the intake structure and 110 feet east of the fuel building. {
The Licensee has stated that separation of the DF0 storage tanks does not meet the technical requirements of Section III.G.2.b. The area around the tanks is nearly free of combustibles. The combustible loading concept is not relevant because this is not an enclosed space. The tanks are i buried atmospheric tanks designed to meet NFPA 30 requirements. The DF0 ;
transfer pump and associated control instrumentation, cables, and piping '
for each tank are underground. Tank accessways are separated by a center-to-center horizontal distance of 16 feet, 6 inches. Each accessway is ;
surrounded by a 10-inch-high curb. No fire detection or automatic fire suppression systems are provided at the tanks. l l
7.3 Evaluation '
The fire protection in Fire Area Y-1 does not comply with the technical requirements of Section III.G.2.b of Appendix R because redundant trains of cables and equipment are not separated by a horizontal distance of
_ ___j
t a t 4
I l
more than 20 feet free of intervening combustibles or fire hazards and because fire detectors and automatic fire suppression systems are not !
installed in the fire area. '
i'he staff was concerned that the separation of redundant DF0 storage 1 tanks by less than 20 feet may create a path for the spread of fire 1 between redundant safe shutdown systems and that the lack of fixed l suppression systems and fire detectors throughout this fire area may j permit the fire to continue and result in the loss of safe shutdown '
capability. However, because of the negligible combustible loading near the tanks, it is not expected that a fire of significant magnitude or duration would develop.
No intervening combustibles exist between the tanks although the possibility exists for transient combustibles or a fuel oil spill during tank filling operations. Should a fire occur during tank filling, it would be detected by plant personnel who would alert the control room.
The control room operators would dispatch the plant fire brigade to extinguish the fire. If a fire were to occur, the heat and smoke would i be quickly dissipated into the atmosphere. The curb at each accessway should prevent spilled fuel from entering both accessways in a single incident.
1 The most likely mode of heat transfer from a fire to a tank is radiant energy transfer. However, the accessway hatch is normally closed and the top of the tank is approximately 3 feet below the hatch. This arrange-ment should minimize the amount of radiant energy absorbed by the tank.
Therefore, ignition of fuel in a tank is very unlikely. Similarly, the location of the DF0 transfer pump and associated cables and their instrumentation inside the accessway protect this equipment from fire damage.
Despite the separation of the redundant DF0 storage tanks by less than 20 feet and the lack of fire detectors and automatic fire suppression systems, there is reasonable assurance that a fire will not result in the loss of safe shutdown capability. Therefore, the staff finds that separating the tanks and associated cables and equipment by a horizontal distance of more than 20 feet and installing fire detectors and automatic fire suppression systems in this section of Fire Area Y-1 would not significantly increase the level of fire protection.
7.4 Conclusion
' Based on the above evaluation, the staff concludes that the existing fire protection provides an acceptable level of protection. Therefore, the exemption can be granted.
8.0
SUMMARY
Based on the evaluation, the staff has concluded that the level of fire safety in the areas listed below is equivalent to that achieved by compliance with the technical requirements of Section III.G of Appendix R to 10 CFR 50 and, therefore, the Licensee's requests for exemption in these areas can be granted:
.\
..v, f 1. Fire Area A-4.
Fire barrier (water curtain) between Fire Areas A-4 and A-4a pursuant to Section III.G.2.a. Additional information provided in Section 2.0.
- 2. Fire Area A-4.
Separation distance between redundant trains of cables and equipment and installation of fire detectors and automatic fire suppression -
systems pursuant to Section III.G.2.b. Refer to Section 3.0 for additional information.
- 3. Fire Area A-4.
Enclosure of one train of safe shutdown cables in a 1-hour fire rated enclosure and installation of fire detectors and automatic fire suppression systems pursuant to Section III.G.2.c. Refer to Section 4.0 for additional infonnation.
4 Fire Area E-1.
Separation. distance between redundant trains of cables and equipment pursuant to Section III.G.2.b. Refer to Section 5.0 for additional ,
information.
- 5. Fire Area T-1.
Separation distance between redundant trains of cables and equipment pursuant to Section III.G.2.b. Refer to Section 6.0 for additional information.
- 6. Fire Area Y-1.
Separation distance between redundant trains of equipment pursuant to Section III.G.2.b. Refer to Section 7.0 for additional infonna-tion.
Based on the evaluation, the staff concluded that the level of fire safety in the area listed below is in compliance with the technical requirements of Section III.G of Appendix R and, therefore, the Licensee's request for exemption was not necessary:
- 1. Fire Area A-4. i Fire barriers between redundant trains of cables pursuant to Section III.G.2.a. Additional infonnation is provided in Section 2.0.
9.0 PRINCIPAL CONTRIBUTOR: John Stang This safety evaluation was prepared based on a Technical Evaluation Report prepared by Franklin Research Center (FRC) under a contract with the U.S. Nuclear Regulatory Commission (NRC).
Dated: November 12, 1987
__- __ a