ML17215A759
| ML17215A759 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 02/21/1985 |
| From: | Williams J FLORIDA POWER & LIGHT CO. |
| To: | Thompson U Office of Nuclear Reactor Regulation |
| References | |
| L-85-71, NUDOCS 8502270105 | |
| Download: ML17215A759 (22) | |
Text
REGULATORY NFORMATION DISTRIBUTION S EM (RIDS)
"ACCESSION NBR;8502270105 DOC ~ DATE: 85/02/21 NOTARIZED; NO FACIL:50 335 St ~ Lucie Plant~
Unit 1< Florida Power L Light Co, AUTH,NAME AUTHOR AFFILIATION WILLIAMS'<W.
Flor ida Power 8 Light Co, RECIP ~ NAME RECIPIENT AFFILIATION THOMPSONgUeL.
Division of Licensing DISTRIBUTION CODE:
A006D COPIES RECEIVED:LTR ENC TITLE:
OR Submittal: Fire Protection NOTES OL: 02/01/76
SUBJECT:
Forwards Rev 5 to fine hazard analysis
~ Rev 5 provides addi technical
(,lustification for structural steel exemptions previously r equested L addi edi torial corrections.
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FLORIDAPOWER & LIGHTCOMPANY PEB 2 1 1985, L-85-71 Office of Nuclear Reactor Regulation Attention: Mr. U.L. Thompson, Director Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C. 20555
Dear Mr. Thompson:
RE:
ST. LUCIE UNIT 1 DOCKET NO. 50-335 FIRE P ROTE CTION Attached is Revision 5 to the Fire Hazard Analysis for St. Lucie Unit 2.
Please replace the previous pages with the revised pages attached.
All additions and changes are identified by revision bars in the margins.
Revision 5 provides additional technical justification for the structural steel exemptions previously requested and additional editorial corrections.
Should you have any questions regarding this submittal, please advise.
Very truly yours,
~
~
. W. Williams, Jr.
roup Vice President Nuclear Energy Department JW W/SJR/pw Attachment cc:
Dr. J. Nelson Grace, Region II Harold F. Reis, Esquire 8502270105 85022i PDR
@DOCK 05000335 F
PDR t
PFOPLE... SERVING PEOPLE
Exem tion A3 An exemption is requested from Section III-G 2.a of Appendix R because fire barrier materials do not completely cover all structural steel supporting steel conduits which are wrapped to provide separation in accordance with Appendix R. Fire barrier materials are installed on conduit support steel for a minimum of 18 inches from the conduit attachment.
Evaluation A3 1)
An ionization type smoke detection system is provided as shown on drawing 8770-G<13.
Safety-related areas of the Reactor Auxiliary Building are covered with this system which provides both local indication and Control Room annunciation.
2)
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in the area.
3)
Florida Power and Light utilizes the defense-inMepth approach to
. fire protection at the St. Lucie Plants.
Accordingly, administrative procedures are in effect which control the amount of transient combustibles in safety related areas of the plant.
Notwithstanding this fact, the postulated fire which may threaten the structural integrity of the conduit supports is an exposure fire generated from transient flammable liquids.
The following analysis addresses this concern.
a)
From the NFPA Fire Protection Handbook, 15th Edition, Figure 5+E, the "E" Time Temperature Curve indicates that 1000 F is achieved in approximately 5
minutes.
This 5
minute time increment is then considered on the "E" Fire Endurance Curve to determine the amount of combustibles necessary to generate this temperature.
A combustible loading of 0.833 lbs/sq. ft. is extrapolated and when multiplied by the floor area of the space in question (Zone 60-A: "A"Switchgear Room = 1471 sq. ft),-a value of 1225.3 lbs results (1471 sq. ft)(0.83 lbs/sq.ft.) = 1225.3 lbs.
R5 In order to present this data in terms of quantity of flammable liquids necessary to present a
1000 F
exposure to in situ combustibles and structural steel suppor ting
- conduits, a
conversion from weight to volume is necessary.
Noting from Table 5<D, of the NFPA Handbook, the "E" Temperature Curve is considered a severe fire exposure based on, among other things, flammable liquids.
Therefor e, a direct conversion from weight to volume is considered acceptable.
As such, No. 2 Fuel Oil was selected as the flammable liquid.
With a weight per gallon of 7.3 lbs/gal a quantity of 168 gallons results (1225.3 lbs)/(7.3 lbs/gal)=
168 gaL This is determined to be incredible because of the large amount of liquid necessary and the fact that administrative controls would exclude such a gross violation of plant procedures.
4)
In the unlikely event that a failure of administrative controls permits excessive amounts of transient combustibles to enter safety related
Bl
ar eas and in the even more unlikely event that ignition of these materials occurs, the amount of combustibles involved would not be expected to generate enough. heat to affect the integrity of the structural steel conduit supports.
This position is held due to the fact that the amount of transient combustibles identified in item 1 above is not a credible transient fuel load and fire is not expected to involve in situ combustibles because:
a)
Any in situ flammable or combustible liquids would be enclosed in piping, pumps, motors, etc.
b)
The majority of in situ combustibles is electrical cabling.
c)
Cables are either coated with Flamastic or meet IEEE-383 flammability criteria.
d)
Solid bottom cable trays are generally utilized as the lowest tray.
e)
The results of EPRI Research Project, Assessment of Ex osure Fire Hazards to Cable Tra s dated January, 1981, (Test No. 27) indicate that damage to cables in baffled cable trays (trays having a shield or solid bottom) did not occur during the test.
The test parameters included approximately 17 gallons of No. 2 fuel oil which burned unchecked for 15 minutes.
The test data showed a
ceiling temperature of 455 F
and an average temperature at the bottom of the tray of about 1300 F and concluded, "Nevertheless, post-test inspection of the cable within the baffled tray showed no visual evidence of charring,"
indicating that cabling did not contribute to the fire.
Based on the above, ignition of major in situ combustibles is not considered probable.
5)
While not considered probable, in the unlikely event that a fire does start and involve in situ combustibles, deleterious effects of heat on structural steel supporting conduit is not considered credible due to the following reasons.
a)
The need, extent and type of structural steel fire protection is based primarily on the combustible loading of the area, design loading of the structural members and the structural steel shape, size and configuration.
b)
The fire hazards analysis at the St. Lucie Plants makes a very conservative assumption that all combustibles within an area ar e available for instantaneous combustion including any combustible fluids contained in operating equipment (grease, oils, etc.).
This analysis, however unrealistic, shows that no area exceeds the equivalent of an E-119 three hour fire.
A normally developing fire is characterized by flame front moving over a surface and/or flames localized to a stationary source which, depending on the continuity of fuel packages, may or may not develop to flashover.
However, it is not reasonable to assume that a credible fire condition, throughout a fire area,
. would approach the severity which is represented by the E-119 R5 3a
time/temperature curve.
This position is held because the spacing of fuel packages would not support fire growth and the structure configuration (including volume) would tend to dilute heat from the fire plume.
In addition, intensity of fire willalso be somewhat lower because walls and ceilings would absorb significant amounts of energy rather than act as insulation or radiation barriers.
Structural steel supports are designed for seismic loading (Operating Basis Earthquake) such that values never exceed 60% of yield including the seismic loading (dead weight loading has a factor of safety of four).
In addition to this extra loading margin, other conservatisms in design assure that even this level is not r cached.
This factor of safety is addr essed by SFPE Technology Report 84-1, Predicti Tem erature Rise in Fire Protected Structural Steel Beams indicating that because design stresses are increased for seismic
- concerns, fire endurance is also increased.
To wit, 'Since the critical temperature is related to the reduction in yield strength under normal design conditions, as discussed above, a reduction in the design stress level would result in a corresponding increase in the critical temperature."
Structural steel inherently contains a degree of fire resistance in itself which is a function of steel mass and the exposed heated surface.
As stated in AISI Fire Protection throu h Modern Buildin Codes:
(Fifth Edition 1981)
'Substantial temperature differences, as great as 600F (333C), have been recorded during standard fire tests between upper and lower flanges of a beam.
This difference is accounted for by the direct contact of the upper flange of the beam with a concrete floor above."
R5 Test information submitted by other utilities (Louisiana Power Light, Waterford Unit 3) have indicated no deleterious
'ffects to unprotected structural steel supporting cable trays subjected to an E-119 one hour fire exposure.
Thermo-Lag fire barrier material is installed on structural steel supporting conduit for a minimum distance of 18 inches away from the attachment of the conduit to the support.
In many cases the fire barrier material either exceeds the 18 inch minimum or covers the entire support.
The postulated fire, in order to resemble an E-119 fire, would have to be confined and would therefore affect no more than one of the conduit structural supports.
This is due to the arrangement of the support spacing which is typically 6 to 10 feet on center.
Assuming loss of structural integrity of a single
- support, located within the affected
- space, the remaining supports located on each side would provide adequate support for the conduit assembly.
In addition, the conduit fire barrier systems are attached to the'conduit using stainless steel tie wires or banding which willinsure that the fire barrier material remains attached to the conduit in event of support failure.
P
-3b-
I 1
6)
It is unrealistic to assume that a fire could start and continue for any significant length of time without fire brigade intervention.
Summary:
Based on NFPA Fire Endurance Curves referenced in item 3 above, the quantity of transient fire loads necessary to generate a
temperature of 1000 F is not credible.
A fire involving in situ combustibles is not likely to duplicate the E-119 time-temperature curve because spacing of fuel packages would not support fire growth and structure configuration (volume, ventilation, heat sinks, etc.) would dilute heat from the fire.
R5'ailure of structural steel supporting conduits is not probable because of heat sinks created by concrete structures, partial fire barrier protection of conduit supports and high loading factors utilized in designing structural steel conduit supports.
C Fire induced failure of a structural steel conduit support would not affect the integrity of the fire barrier protecting the conduit.
Fire brigade actions willlimit the consequences of a fire.
Conclusion A3 Based on our evaluation, the provision of fire barrier materials on the structural steel supports for wrapped conduits would not augment or materially enhance the safety of the plant.
Therefore, we conclude that this is an acceptable exemption from Appendix R to 10CFR50, Section III-G-2.a.
-3c-
A exemption is requested from Section III-G.2.a of Appendix R for electrical penetrations to the containment from the.RAB fire zone 77 (Train "A"Electrical Penetration Area) because no penetration fire seals are provided.
All of the.
penetrations are sealed air tight, however they do not constitute a typical fire rated assembly.
Evaluation A4 1.
Ionization type smoke detection is provided as shown on drawings 8770-G<13.
2.
Portable fire extinguishers and a fire standpipe system with hose stations are available. for use in this area.
3.
Electrical penetration nozz)es and sleeves are sealed in the RAB side with 1-1/2 inch thick by 20 inch diameter ASTM Grade A-36 plates over the sleeve opening (sleeve is Schedule 80 ASME SA 106 Gr.B and is housed in a 36 inch thick concrete shell) and fillet weld to embedded plate.
Weld is the same as used on penetration header plates.
A-36 plates are designed as Seismic Category l. This seal has been air tested at -.25" W.G.
The 1-1/2 inch thick by 20 inch diameter ASTM Grade A-36 plate continuously welded over the sleeve opening forming this air tight seal, is equal to or better than a three hour fire rated assembly.
See FSAR Section 3.8.
4.
Between the 36 inch thick concrete shell and the 3%/8 inch thick reinforced steel containment, there is an annulus of 48 inches which the penetration passes through.
The cables are covered with a 12 inch diameter sleeve as they pass through the annulus.
The annulus has negligible combustible loading.
5.
At the Reactor Containment Building side, electrical penetrations pass through a schedule 80 sleeve which is continuously welded to the 3%/8 inch thick reinforced steel containment (reinforced for penetration purposes) on both sides.
The electrical penetrations are terminated approximately 8 inches beyond the steel containment.
A schedule 80 ASME SA 234 pipe cap is continuously welded as per ASME III, Class MC, to the penetration sleeve, sealed and air tested at approximately 44 psid.
Conclusion A4 Based upon the spatial separation provided by the annular space, the thickness of the concrete containment building wall and the 3%/8 inch steel containment with welded steel penetration
- sleeves, a level of protection equivalent or superior to a typical 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rated assembly is provided.
In addition, smoke detection equipment in this area provides early warning of any developing fire and manual fire suppression equipment is available in the area to control and extinguish such a fire. The installation of fire rated penetration seals would not materially enhance the safety of the plant.
Therefore we conclude, this is an acceptable exemption to Appendix R to 10CFR50, Section III-G.2.a.
R5
Exem tion B2 An exemption is requested from Section III-G.2a of Appendix R because fire retardant coatings are not provided for the structural steel supporting the steel conduits which are wrapped to provide separation in accordance with Appendix R.
Evaluation B2 1)
Ionization type smoke detection is provided (as shown on Drawings 8770-G<13) and an Automatic Halon 1301 Suppression system is provided in this fire area.
2)
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in the Area.
3)
See Evaluation A3; Items 3 thru 6.
R5 Conclusion B2 See Conclusion A3.
3)
The entries to fire zone 41 are inside labyrinth entry corridors with wire mesh access doors.
4)
The holdup tanks would tend to rapidly dissipate heat generated by a fire in Fire Area "C" through the tank walls into the contained water.
5)
There is no continuity of combustibles in fire zone 41, which will mitigate the propagation of fire from Fire Area "C: to adjacent Fire Area "E".
Conclusion C3 Based on our evaluation the existing fire barrier provides adequate separation.
The installation of fire doors at the entries to holdup tank room would not augment or materially enhance the safety of the plant since they would not aid in preventing fire migration through the entries.
- There, we conclude, this is an acceptable exemption to Appendix R to 10CFR50, Section III-G.2.a.
Exem tion C4 An exemption is requested from Section III-G.2a of Appendix R because fire retardant coatings are not provided for the structural steel supporting the steel conduits which are wrapped to provide separation in accordance with Appendix R.
Evaluation C4 1)
Ionization type smoke detection system is provided as shown on drawings 8770-G<13.
2)
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in the Fire Area.
3)
See Evaluation A3, Items 3 thru 6.
R5 Conclusion C4 See Conclusion A3.
CS An exemption is requested from Section III-G.2a of Appendix R for electrical penetrations to the containment from the RAB fire zone 78 (Train 'B" Electrical Penetration Area) because no penetration fire seals are provided.
All of the penetrations are sealed air tight, however they do not constitute a typical fire rated assembly.
Evaluation C5 See Evaluation A4.
Conclusion C5 See Conclusion A4.
Evaluation E4 1)
Ionization type smoke detection system is provided as shown on drawings 8770-G<13.
2)
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in the Area.
3)
See Evaluation A3, Items 3 thru 6.
Conclusion E4.
See Conclusion A3.
An exemption is requested from Section III-G.2.a of Appendix R for mechanical penetrations to the containment from the RAB fire zones 46 (Containment Purge),
61 (RAB HVAC Equipment Room) because no penetration fire seals are provided.
All of the penetrations are sealed air tight, however they do not constitute a typical fire rated assembly.
Evaluation E5 1.
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in this area.
2.
Ionization type smoke detection system is provided as shown on Drawings 8770-G<13.
3.
All mechanical penetrations are sealed air tight and penetrate a 36 inch thick concrete shell from the RAB into the containment.
This seal has been air tested at.25"wg.
Between the 36 inch concrete shell and the steel containment, there is an annulus of 48 inches which the penetrations passes through.
The annulus has negligible combustible loading.
At the Reactor Containment Building side, there is a 3%/8 inch thick reinforced steel containment (reinforced 3%/8 iriches for penetration purposes).
The penetrations pass through this steel containment, sealed air tight and tested at approximately 44 psid.
4.
Six general. types of piping penetration assemblies are provided.
The penetration'ssemblies consists of a containment vessel penetration
- nozzle, a process
- pipe, a Shield Building penetration sleeve and a shield building bellows seaL In the case of cold penetrations the containment vessel penetration nozzle is an integral part of the process pipe.
In the case of hot and semi-hot penetrations, a multiple flued head is provided as an integral part of the process pipe.
A guard pipe, which encloses the process pipe and directs any fluid released back into the containment, is welded to the flued head.
For hot penetrations an expansion joint metal bellows is welded to the flued head the the containment vessel penetration nozzle to accommodate thermal movements.
The containment vessel penetration nozzles are designed to meet the requirements for Class MC vessels under ASME Code, Section IIL 5.
At the terminal of a piping penetration assembly near the Shield Building a low pressure leakage barrier is provided in the form of a Shield Building bellows seaL The bellows provides a
flexible membrane type closure between the Shield Building penetration
- sleeve, which is embedded in the Shield Building, and the process pipe.
The Shield Building bellows is designed to withstand a
design differential pressure of five psig and provide an adequate leak-tight seal consistent with overall allowable Shield Building leakage.
For additional mechanical penetration description and details see FSAR in Section 3.8.
6.
All of the penetrations are sealed air tight by continuous welding with a minimum of two passes.
The air tight penetration seals constitute more than a three hour fire rated assembly.
Conclusion F5 Based upon the spatial separation provided by the annular space, the thickness of the concrete containment building wall and the pipe penetration details described above, a level of protection equivalent or superior to a typical 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
fire rated assembly is provided.
In addition, smoke detection equipment in this area provides early waining of any'developing fire and manual fire suppression equipment is available in the area to control and extinguish such a fire.
The installation of fire rated penetration seals would not materially enhance the safety of the plant.
Therefore we conclude, this is an acceptable exemption to Appendix R to 10CFR50, Section III-G.2.a.
An exemption is requested from Section III-G<.a of Appendix R for mechanical penetrations to the containment from the'RAB fire zones 33 (Piping Penetration Room), and 45 (RAB Pipe Tunnel) because no penetration fire seals are provided.
All of the penetrations are sealed air tight, however they do not constitute a
typical fire rated assembly.
Evaluation J5 1.
Fire area "J" contains negligible combustible loading.
2.
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in this fire area.
3.
See Evaluation E5 (Items 3 through 6).
Conclusion J5 R5 See Conclusion E5.
Conclusion K3 See Conclusion A4.
An exemption is requested from Section III-G.2.a of Appendix R for mechanical penetrations to the RAB fire zones 33 (Piping Penetration Room), 45 (RAB Pipe Tunnel), 46 (Containment Purge), and 61 (RAB HVAC Equipment Room) from the containment because no penetration fire seals are provided.
All of the penetrations are sealed air tight, however they do not constitute a typical fire rated assembly.
Evaluation K4 h
R5 1.
Portable fire extinguishers are available for use in this area.
2.
Ionization type smoke detection system is provided as shown on Drawings 8770-G<13.
3.
All mechanical penetrations are sealed air tight.
At the Reactor Containment Building side, there is a 3%/8 inch thick reinforced steel containment (reinforced 3%/8 inches. for penetration purposes).
The penetrations pass through this steel containment, sealed air tight and tested at approximately 44 psid.
Between the steel containment and the 36 inch concrete shell, there is an annulus of 48 inches which the penetrations pass through.
The annulus has negligible combustible loading.
The penetrations pass from the 48 inch annulus thru a 36 inch concrete shell into the RAB. This penetration seal has been air tested at.25"wg.
4.
Six general types of piping penetration assemblies are provided.
The penetration assemblies consists of a containment vessel penetration
- nozzle, a process
- pipe, a Shield Building penetration sleeve and a shield building bellows seaL In the case of cold penetrations the containment vessel penetration nozzle is an integral part of the process pipe.
In the case of hot and semi-hot penetrations, a multiple flued head is provided as an integral part of the process pipe.
A guard pipe, which encloses the process pipe and directs any fluid released back into the containment, is welded to the flued head.
For hot penetrations an expansion joint metal bellows is welded to the flued head.
and the containment vessel penetration nozzle'o accommodate thermal movements.
The containment vessel penetration nozzles are designed to meet the requirements for Class MC vessels under ASME Code, Section IIL 5.
At the terminal of a piping penetration assembly near the Shield Building a low pressure leakage barrier is provided in the form of a Shield Building bellows seaL The bellows pr ovides a
flexible membrane type closure between the Shield Building penetration
- sleeve, which is embedded in the Shield Building, and the process pipe.
The shield Building bellows is designed to withstand a
design differential pressure of five psi and provide an adequate leak-tight seal consistent with overall allowable Shield Building leakage.
For additional mechanical penetration description and details see FSAR in Section 3.8.
6.
All of the penetrations are sealed air tight by continuous welding with a minimum of two passes.
The air tight penetration seals constitute more than a three hour fire rated assembly.
Conclusion K4 See Conclusion E5.
R5
~
~
Conclusion N1.
'U Based on our evaluation, the 7 ft 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rated partitions and one hour conduit protection provide adequate separation of the redundant charging pumps and their related equipment.
The extension of the walls to full height would not, augment or materially enhance the safety of the plant since it would not provide additional protection for redundant charging pumps.
- There, we conclude that this is an acceptable exemption from Appendix R to 10CFR50, Section III-G.2.a.
Exem tion N3 h
An exemption is requested from Section III-G.2.a of Appendix R for watertight door RA-8 because the fire rating of the custom manufactured door is not Underwriters Laboratory listed.
Evaluation N3 - See Evaluation J4.
Conclusion N3 - See Evaluation J4.
Exem tion N4 An exemption is requested from Section III-G.2.a of Appendix R because fire retardant coatings are not provided for the structural steel supporting the steel conduits which are wrapped to provide separation in accordance with Appendix R.
Evaluation N4 1)
Ionization type smoke detection system is provided as shown on drawings 8770-G<13.
2)
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in the Fire Area.
3)
See Evaluation A3, Items 3 thru 6.
R5 Conclusion N4 See Conclusion A3;
a A
N
Exem tion 05 An exemption is requested from Section III-G.2.a of Appendix R because fire retardant coatings are not provided for the structural steel suppor ting the steel conduits which are wrapped to provide separation in accordance with Appendix R.
Evaluation 05 1)
Ionization type smoke detection system is provided over essential cable trays in this fire area as shown on drawings 8770-G<3.
2)
Portable fire extinguishers and a fire standpipe system with hose stations are available for use in the area.
3),
See Evaluation A3, Items 3 thru 6.
Conclusion 05 R5 See Conclusion A3.
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