ML20198C234
| ML20198C234 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/07/1985 |
| From: | Reinaldo Rodriguez SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Thompson H Office of Nuclear Reactor Regulation |
| References | |
| RJR-85-497, TAC-52291, TAC-53444, TAC-58032, NUDOCS 8511120027 | |
| Download: ML20198C234 (60) | |
Text
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SACRAMENTO MUNICIPAL UTluTY DISTRICT C 6201 S Street, P.O. Box 15830, Sacramento CA 95852-1830,1916) 452-3211 RJR 85-497 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA November 7,1985 DIRECTOR OF NUC 2 REACTOR REGULATION ATTENTION HUGH L THOMPSON JR DIRECTOR DIVISION OF LICENSING US NUCLEAR REGULATORY COMMISSION WASHINGTON DC DOCKET 50-312 RANCHO SECO NUCLEAR GENERATING STATION UNIT NO. 1 REVISED REQUEST FOR EXEMPTION TO SOME REQUIREMENTS OF 10CFR50, APPENDIX R By letters dated February 28, April 4, and May 24, 1985, the District j
1 submitted requests for exemptions to some of the requirements of 10CFR50, Appendix R.
As a result of the completion of the 1985 Rancho Seco Fire Hazard Analysis Report (FHAR) update, a number of clarifications are required to the previously submitted exemptions. As a result of the NRC August 12-17, 1985 fire protection audit, the District is submitting an i
additional exemption request for lack of suppression in the Control Room I
(Exemption 13).
For clarity, the District is submitting a complete update of the previous exemption requests and it includes a list of required modifications and their respective schedule for installation (Attachment 1), and the exemption requests (Attachment 3).
This exemption request supercedes the District's earlier exemption requests'of February 28, April 4, and May 24, 1985. To facilitate the NRC review, all revisions to the earlier exemption requests have been indicated by revision bar lines. In addition, Attachment 2 is a summary of the changes between the earlier submittals and this submittal.
For those modifications that have not been completed, the District has compensatory measures in place. The compensatory measures are being handled as if these items were included in our Technical Specifications and the systems are declared inoperable. This assures suitable action is taken that has been accepted by the NRC.
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Hugh L. Thompson November 7, 1985 Since this submittal is an update of the District's February 28, April 4, and May 24, 1985 submittals, an additional application fee is not required.
If you have any questions concerning this submittal, please contact Larry Young at Rancho Seco.
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- ^N R. J. ROD'IGUEZ ASSISTANT GENERAL MANAGER, NUCLEAR Attachments de
ATTACHMENT 1 MODIFICATION SCHEDULE COMPENSATORY EXEMPTION MODIFICATION SCHEDULE MEASURE 1.
72 Hour Cold None N/A N/A Shutdown 2.
RCP Oil Add pipe to tank Installed N/A Collection (T-213B) vent down System to containment floor 3.
Auxiliary Pipe skid drains Install by Fire watch in Feedwater out of area and 12/01/85 accordance with Pumps Lack add flame detectors Technical of Separation in AFW pump area Specifications Add radiant energy Install by Fire watch in barrier and deluge 3/01/86 accordance with system in AFW pump Technical area Specifications 4.
kixiliary Add two fire breaks One installed.
Fire watch in Feedwater in the intervening Install second accordance with Valves cable trays by 11/15/85 Technical Intervening Specifications Combustibles 5.
Cables Inside Add fire break (s)
Installed N/A Containment in the intervening Electrical cable trays Penetration Area 6.
Auxiliary Wrapping conduits Installed N/A Building to protect one l
Electrical train of safe shut-l Penetration down circuits I
Area 7.
F.A. RB1 Additional sprink-Install by Fire watch in Auxiliary lers in hallway to 12/01/85 accordance with Building F.A. RB2 to provide Technical Mechanical separation barrier Specifications Penetration Area 8.
Nuclear None N/A N/A Service Raw Water Pumps a
9.
Nuclear Service None N/A N/A Electrical Building Roof 10.
Auxiliary None N/A N/A Building Roof Area 11.
Nuclear Service None N/A N/A Yard Area 12.
Axiliary None N/A N/A Building Roof Area 13.
Control and None N/A N/A Computer Room Suppression b
ATTACHMENT 2
SUMMARY
OF CHANGES TO PREVIOUS EXEMPTION REQUESTS 1.
72 Hours Cold Shutdown - The changes are minor corrections to accurately reflect the pressure (255 psig) when the Decay Heat Removal System is brought into service and to delete the discussion of the fuel transfer between diesel storage tanks.
2.
Fire Area 68, RCP Oil Collection System - The changes reflect those instruments in the areas that are required for a safe shutdown by the 1985 Rancho Seco FHAR update. Minor changes to the area description and fire loading are provided to make it consistent with 1985 Rancho Seco FRAR update. A more detailed discussion of containing any spilled oil in the containment is provided.
3.
Fire Area 69, Auxiliary Feedwater Pumps - The changes reflect minor revisions to the area description and fire loading to make it consistent with the 1985 Rancho Seco FRAR update.
The deluge system is activated by flame detection instead of heat detection.
4.
Fire Area 69, Auxiliary Feedwater Valves - As a result of the NRC August 12-17, 1985 fire protection audit, one additional fire stop is being added.
The other changes reflect minor revisions to the area description and fire loading to uake it consistent with the 1985 Rancho Seco FHAR update.
5.
Fire Area 68, Cables Inside Containment, Electrical Penetration Area -
The changes reflect those instruments in the area that are required for safe shutdown by the 1985 Rancho Seco FHAR update The other changes reflect minor revisions to the fire loadings to make it consistent with the 1985 Rancho Seco FHAR update.
6.
Fire Area RG1, Auxiliary Building Electrical Penetration Area - The changes reflect a more detailed area description consistent with the 1985 Rancho Seco FRAR update. The other changes reflect minor revisions to the fire loadings to make it consistent with the 1985 Rancho Seco FRAR update.
This revised exemption requests clarifies the fact that it supercedes the District's July 24, 1984 exemption request.
7.
Fire Area RBI, Auxiliary Building Mechanical Penetration Area - The description of the exemption has been revised to include 32 inch diameter exhaust air duct passing above the 6' x 20' opening that is not provided with a rated fire damper.
The safe shutdown circuits / components of concern in Fire Areas RBI and RB2 are defined in more detail.
A detailed area description of Fire Area RB2 has been added and a more detailed area description for RB1 has been provided. The fire hazard analysis section has been revised to provide more detailed information consistent with the 1985 Rancho Seco FHAR update.
8.
Fire Area 110, NSRW Pumps - No change.
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9.
Fire Area 91, NSEB Roof - Minor changes to the area description and fire loading are provided to make it consistent with 1985 Rancho Seco FHAR update.
10.
Fire Area 74, Auxiliary Building Roof Area - Minor changes to the area description and fire loading are provided to make it consistent with the 1985 Rancho Seco FHAR update.
11.
Fire Area 69, Nuclear Service Water Pumps - Minor changes to the area description and fire loading are provided to make it consistent with the 1985 Rancho Seco FHAR update.
12.
Fire Area 74, Nuclear Service Cooling Water Surge Tanks - Minor changes to the area description and fire loading are provided to make it consistent with 1985 Rancho Seco FHAR update.
13.
Fire Area 1, Control and Computer Room - This is a new exemption request that was a result from the NRC August 12-17, 1985, fire protection audit.
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EXEMPTION REQUEST 1 ACHIEVE COLD SHUTDOWN CONDITIONS WITHIN 72 HOURS WITH LOSS OF OFFSITE POWER EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption from the requirements of Section III.L of Appendix R to 10CFR50, to the extent that it requires the capability to achieve cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (Section III.L).
DESCRIPTION OF EXEMPTION:
Section III.G.3 requires alternate or dedicated shutdown capability where the requirements of Section III.G.2 are not satisfied or redundant trains are located in the same fire area and may be subject to damage from the rupture or inadvertent operation of a fire suppression system.
Section III.L which defines the requirements for the alternate and dedicated shutdown capability, requires that the system provided be able to achieve cold shutdown conditions within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> without offsite power and maintain cold shutdown conditions thereafter.
With the absence of offsite power, the limiting factor is the maintenance of RCS pressure while in natural circulation.
Therefore, RCS depressurization controls the cooldown rate, which is limited by pressurizer heat loss. A specific evaluation was performed for Rancho Seco. The results show the minimum time to reach cold shutdown under the above conditions exceeds the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> requirement.
This situation has been identified in exemption requests filed by other B&W NSSS facilities.
BASIS FOR ACCEPTABILITY:
The evaluation done for Rancho Seco consists of three sub-analyses. The first, called the Shutdown Analysis, demonstrates the capability of the natural circulation cooldown.
The second, Diesel Generator Availability, demonstrates the adequacy of the Diesel Generator Fuel Supply.
Finally, the third analysis demonstrates that an adequate water supply is available for the duration of the shutdown.
SHUTDOWN ANALYSIS:
A specific analysis for Rancho Seco was performed by B&W using the criteria defined in 10CFR50, Appendi:: R.
The assumptions used in the depressurization analysis are:
1.
A loss of offsite power event has occurred.
The RCS is initially stabilized by removing decay heat using the Main Steam Safety Valves. The RCS flow is by natural circulation. RCS pressure is maintained by the saturated water in the pressurizer.
RCS bulk temperature is maintained less than Tsat by using the Main Steam Dump Valves.
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Exemption Request 1 (Cont.). 2.
Pressurizer hc.aters and spray are not required, and auxiliary spray and PORVs are not allowed to operate.
3.
The High Pressure Injection (HPI) System is used to naintain level in the pressurizer.
- 4. 1The heat. loss from the pressurizer is proportional to the temperature of the wall and ambient air temperature moving freely past the pressurizer.
The natural circulation cooldown without pressurizer heaters or spray requires the RCS rate of cooldown to be limited by the pressurizer cooldown (through ambient losses).
Thus the RCS cooldown " tracks" the pressurizer cooldown.
The analysis initially assumed the pressurizer level was. maintained at 180 inches (normal). 'To test the sensitivity of the depressurization, calculations using variations of + 50% on ambient heat loss to the building, changes in pressurizer level to 100 and 300 inches, and starting initial pressures of 2170 psig and 1700 psig were performed.
The results show that the variation of ambient heat loss produced the most significant changes. The
-extremes ranged from 60 --200 hours to depressurize to 255 psig, with the majority of the cases exceeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The base case required approximately.100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> to depressurize.
The most conservative case varied from the base case only in that.the heat loss from the pressurizer was decreased by 50% which resulted in a depressurization time of approximately p
200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br />. From the 255 psig point, an additional five hours is estimated to reach cold shutdown conditions using the Decay Heat Removal System.
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Thefreport also. included an analysis to illustrate that a 1% minimum delta K/K
. shutdown margin can be maintained with shrinkage made up by the Borated Water i
Storage Tank (BWST) with no boron' addition through the chemical addition I
system. The assumptions and limitations used in the analysis are as follows:
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1.
The make-up tank input volume is limited to 1,200 gallons.
2.
Pressurizer was excluded from the boron concentration analysis by keeping l
the pressurizer level at 200 inches or higher.
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No auxiliary spray is allowed in support of assumption 2, above.
4.
.No credit is taken for xenon or samarium.
DIESEL GENERATOR AVAILABILITY:
On loss of offsite power, the emergency diesel generators provide emerggncy power. Each emergency diesel generator is supplied fuel oil from a dedicated 50,000 gallon diesel fuel oil storage tank. Technical Specifications' require a minimum of 35,000 gallons of fuel oil be maintained in each tank.
.Therefore, fuel is available for operating both emergency diesel generators at full rated load for a minimum of 175 hours0.00203 days <br />0.0486 hours <br />2.893519e-4 weeks <br />6.65875e-5 months <br /> to as long as 250 hours0.00289 days <br />0.0694 hours <br />4.133598e-4 weeks <br />9.5125e-5 months <br />.
If necessary, additional supplies of diesel fuel oil can be brought onsite by tanker. trucks from local suppliers to support an extended loss of offsite power event.
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Exemption Request 1 (Cont.)
- WATER SUPPLY:
With a loss of offsite-power, the primary source of water for heat removal, until the decay heat removat system is cut in, is furnished by the Auxiliary Feedwater System from the Condensate Storage Tank.
.A minimum of 250,000 gallons is maintained in the tank per Technical Specification which provides sufficient water for decay heat removal for a period in excess of one day.
-The secondary water source is the onsite reservoir. The onsite reservoir contains 880,000,000 gallons of usable capacity which provides a 3000 day supply of condensate makeup.
Suction from the AFW pumps must be manually transferred from the Condensate Storage Tank to obtain gravity flow from the onsite reservoir.
CONCLUSION:
The analysis results indicate that Rancho Seco can achieve cold shutdown conditions without adverse effects on the reactor's integrity without offsite power in approximately 205 hours0.00237 days <br />0.0569 hours <br />3.38955e-4 weeks <br />7.80025e-5 months <br />. Therefore, SMUD requests an exemption from the requirement to achieve cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
l EXEMPTION REQUEST 2 F.A. 68 REACTOR COOLANT PUMP OIL COLLECTION SYSTEM CAPACITY OF COLLECTION TANKS EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests exemption for Rancho Seco from the capacity requirements of Appendix R,Section III.0 for the RCP Oil' Collection System.
DESCRIPTION OF EXEMPTION: ~
Rancho Seco has two RCP Oil Collection Systems for the four Reactor Coolant Pumps located in the containment.
Each system collects oil from two of the four Reactor Coolant Pumps.
The system consists of two catch basins which are connected by a 4 inch drain pipe to a 200 gallon tank.
The tank is equipped
~ with a valved and capped drain line and a vent / overflow.
.The system was' originally designed based on failure of only one RCP Lube Oil System since each Reactor Coolant Pump has an independent lube oil system.
' Consequently, the capacity of the collection tank (200 gallons) was sized based on the 190 gallons of lube oil contained in only.one pump motor rather than on the combined volume of oil from the-two-Reactor Coolant Pumps connected to it.
SAFE SHUTDOWN REQUIREMENT:
Appendix R, Secticn III.0, requires that leakage from the RCP Lube Oil System shall be collected and drained to a vented closed container that can hold the
-entire lube oil system inventory.
Cabling'for the following safe shutdown equipment is in the area of the
- Reactor Coolant Pump Motors:
Location 68-1 Neutron source range monitor (XE-00006)
RCS T' narrow range (TE-21033) h RCS T ' narrow' range (TE-21029) h RCS T wide range (TE-21031C) h RCS T wide range (TE-21023A, B and TE-210250) c
y Exemption Request 2 (Cont.) Location 68-2 Neutron source range monitor (XE-00005)
RCS T narrow range (TE-21034) h RCS T narrow range (TE-21030) h RCS T wide range (TE-21032C) h RCS T wide range (TE-21024A, B, C) c Steam Generator E205B wide range level (LT-20502A)
Pressurizer wide range level (LT-21503D)
AREA DESCRIPTION:
The entire Reactor Building is designated as Fire Area 68 and is broken into smaller sub-areas. ' Location 68-1 consists of the north steam generator compartment from elevation (-)25 feet to elevation 67 feet and contains Steam Generator E-205A, Reactor Coolant Pumps (RCP) P-210A and P-210B, and the RCP Oil Leak Collection Tank T-213A.
The floor area is 1,850 square feet and the volume is 126,100 cubic feet. A concrete secondary shield wall surrounds the compartment. A shielded labyrinth opening at the bottom connects to locations 68-3 and 68-4.
Fire Zone 68-1 is open at elevation 67 feet to location 68-11.
The RCP Oil Leak Collection Tank T-213A is located on the floor at elevation (-)25 feet in the northeast corner. Normal Sump A is located approximately 17 feet south of T-213A and is connected to Normal Sump B via a below floor pipe. The RCP Oil Leak Collection Tank T-213A vent / overflow is piped to drain to the Reactor Building floor from where it will flow to the normal sumps.
Location 68-2 consists of the south steam generator compartment from elevation
(-)25 feet to elevation 67 feet and contains Steam Generator E-205B, Reactor Coolant Pumps P-210C and P-210D, Pressurizer V-215, Pressurizer Relief Tank V-219, and the RCP Motor Oil Leak Collection Tank I-213B.
The ficor area ir 1850 square feet and the volume is 126,100 cubic feet. A concrete secondary shield wall surrounds the compartment. A shielded labyrinth opening at the bottom connects to locations 68-3 and 68-4 and the top, at elevation 67 feet, is open to location 68-11.
The RCP Oil Leak Collection Tank T-213B is located approximately eight feet southwest of the Pressurizer V-215 on the pressurizer service platform at elevation five feet. Normal Sump B is located at elevation (-)25 feet approximately eight feet northeast of Steam Generator E-205B.
The RCP Oil Leak Collection Tank T-213B vent /over flow is piped to elevation (-)25 feet to drain to the Reactor Building floor from where it will flow to the normal sumps (see Figures 1 and 2).
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Exemption Request 2 (Cont.) The drain piping from the normal sumps is routed outside containment through the two containment isolation valves. The piping is then routed through a loop seal to the-the Reactor Building Drain Accumulation Tank..The level in the drain accumulation tank is automatically controlled by the outlet valve.
After exiting the drain accumulation tank, the piping is routed to the east Decay Heat Cooler Pump Room sump. The'1evel is controlled in this sump by the automatic starting and stopping of the sump pump. The piping from the sump is routed to the miscellaneous waste tank.
Piping from the Reactor Building normal sumps through the second isolation valve is seismically qualified.
' Piping downstream is nonseismic.
FIRE PROTECTION SYSTEMS:
The fire detection in each location consists of two infrared flame detectors located.near each RC Pump Catch Basin. A closed circuit television with video display in the Control Room is also available for monitoring the area for fire.
To eliminate the potential fire hazard resulting from a possible oil spill, each Reactor Coolant Pump Motor has upper and lower steel catch basins to contain the oil and then direct it to a collection tank. There are two oil collection tanks. Tank T-213A is in location 68-1, at. elevation (-)25 feet, and collects the oil from RCPs P-210A and P-210B.
Tank T-213B is in location 68-2, at. elevation five feet, and collects oil from RCPs P-2100 and P-210D.
Each oil collection tank has a capacity of 200 gallons. The drain line from each catch basin to the tank does not contain any valves. The vent pipe on the oil collection tanks permits drainage to the normal-sumps.
FIRE HAZARD ANALYSIS:
Location 68-1 contains combustibles consisting of 103 lbs of flame resistant cables and 380 gallons (190 gallons per RCP) of lube oil. The combustible fire load for this location is 28,000 BTU / square feet, which if totally consumed..would correspond to a fire severity of 21 minutes on the ASTM E-119 atandard time-temperature curve.
Similarly, location 68-2 contains combustibles consisting of 644 lbs flame resistant cables and 380 (190 gallons per RCP) gallons of lube oil.
The combustible fire load for this location is 32.000 BTU / square feet, which if totally consumed, would correspond to a fire severity of 24 minutes on the.
ASTM E-119 standard time temperature curve.
Approximately 190 gallons of lube oil is contained within the lube oil system for each Reactor Coolant Pump Motor. The oil has a flash point of 400 degrees-and falls within the Type IIIB classification of NFPA 30 combustible liquids and is not considered to present a fire flash back hazard. Because the oil does not pcesent a fire flashback hazard, the flame arrestor has been removed.
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r Exemption Request 2 (Cont.) Traffic into the Reactor Building is under strict administrative control.
Therefore, during operating conditions a fire involving transient combustibles is not considered probable for either location 68-1 or 68-2.
There is no automatic suppression in the Reactor Building.
The probability of both RCP Lube Oil Systems failing simultaneously is extremely remote.
In the unlikely event of a seismic event resulting in complete rupture of the Reactor Coolant Pump Motor Lube Oil Systems for all four Reactor Coolant Pump Motors, a total of 760 gallons could be released. 400 gallons would be retained in the lube oil collection system tanks. The remaining 360 gallons would overflow to the Reactor Building floor and would drain to the Reactor Building Normal Sumps. When the oil drains into the sumps, indication is available in the Control room to identify the RC pump motor oil release and the operators will close SFV-66308 to retain the oil in the reactor building.
The Control Room indication of sump input is normally used by the operators to maintain the technical specification leakage limits, so it is monitored closely. Thus, a complete spillage of the Reactor Coolant Pump Motors oil inventory will not result in a fire hazard.
CONCLUSION:
The' District concludes that, although not in strict compliance with Appendix R,Section III.0, the Reactor Coolant Pump Oil Collection System adequately contains any leakage from the lube oil system based on the following justifications:
1.
The probability of both the RCP's Lubricating Oil Systems rupturing at the same time is minimal.
2.
The oil collection system will contain the contents of one RCP's Lubricating Oil System.
3.
The oil collection systems are designed with vents which overflow to the containment normal sumps without an ignition source along the path.
4.
The oil collection systems are Seismic Category 1.
5.
The RCP Lubricating Oil Lift System is designed to operate at 2300 psig.
It is only operated near this pressusre when starting up or shutting down the RCPs, which requires approximately three minutes per pump.
Administrative controls ensure only one RCP is started or shutdown at a time during normal operations.
This limits the possibility of failure of more than one RCP's Lubricating Oil System at a time.
6.
Indication is available in the Control Room to ensure isolation of any pump overflow to the Auxiliary Building. This indication is closely monitored for other technical specification reasons.
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1 Exemption Request 2 (Cont.) Based on the justifications above, the addition of more or larger oil collection tanks will not significantly enhance the fire protection features provided by the current configuration. Therefore, the District requests an exemption from the capacity requirements for the RCP Oil Collection System of Appendix R, Section 111.0.
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AUXILIARY FEEDWATER PUMPS - LACK OF SEPARATION i
EXEMPTION REQUEST:
l Per the provisions of 10CFR50.12,. the District requests an exemption for Rancho Seco from the specific requirements of Appendix R,Section III.G.2,
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requiring one of the following forms of protection for the redundant Auxiliary Feedwater Pumps:
. 1.
Separation by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier.
2.
Separation by at least 20 feet' of horizontal distance without intervening combustibles with fire detection and automatic suppression, i
3.
Enclosure of cables and equipment and associated non-safety circuits of one redundant train in a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated fire-barrier with fire detection and automatic suppression.
DESCRIPTION OF EXEMPTION:
Both trains of Auxiliary Feedvater Pumps (P-318 and P-319) are located in the same fire area. The redundant pumps are not separated by a rated fire barrier or by 20 feet of horizontal separation.
SAFE SHUTDOWN REQUIREMENT:
i At least one train of Auxiliary Feedwater Pumps (P-318 or P-319) is required to be operable in order to achieve and maintain hot shutdown conditions, as well as to achieve cold shutdown.
AREA DESCRIPTION:
a Fire Area 69 is an outside fenced-in area which contains the Nuclear Service Yard equipment. This 33,806 square foot area is surrounded on three sides by l
an unrated 8 foot high cinder block wall supporting a chain link fence. The i
remaining portion of the perimeter consists of the adjoining Reactor and Auxiliary Building walls.
Located in the northwest corner of this area is a missile cage of approximately 825 square feet which encloses the two Auxiliary Feedwater i
Pump-Driver Sets.
The missile cage is an open grating structure approximately l
j 8 feet tall.. The two Auxiliary Feedwater Pump-Driver Sets are installed i
and-to-end within the missile cage with.approximately.2 feet of separation between the. sets-(see Figure 3).
FIRE PROTECTION SYSTEMS:
The AFW pump area is provided with a deluge system. The deluge system is-activated by flame detection which is provided in the missile cage area. A l
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removable radiant energy barrier is also installed between the pump-driver l
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Exemption Request 3 (Cont.),
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sets. The radiant energy barrier is a roll-up door with a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rating. The roll-up door includes remote position indication in the Control Room.
The AFW i
pump skid drains and component cooling water pump skid drains are routed away from the Auxiliary Feedwater Pump area. Manual fire fighting equipment is available within the area.
FIRE HAZARDS ANALYSIS:
I The total fire loading in Fire Area 69 consists of approximately 20 gallons of oil, approximately 4,674 pounds of cable insulation, 20 lbs of PVC, and 16 lbs 4
of battery cases. This results in an average fire loading of 1,786 BTU / square feet, which if totally consumed would correspond to a fire severity of 2 l
minutes on the ASTM E-119 standard time-temperture curve. The fire loading within the immediate vicinity of the Auxiliary Feedwater Pump-Driver Set is also very low, consisting of 10 gallons of oil.
Based on the nature and quantity of the fire loading wihtin the overall area as well as in the immediate vicinity of the pump driver sets, the probability 4
of a fire occurring is extremely remote. However, if a fire occurred, it would be of short duration and small intensity.
The deluge system provides an active method of fire protection for the AFW pumps. The radiant energy shield will prevent a fire on one pump from damaging the redundant pump.
Due to the open nature of the missile cage and the overall fire area, any products of combustion and heat produced by a fire would dissipate to the atmosphere. Since the area is located outside and subject to rain, no damage is expected to result'from normal fire suppression activities.
CONCLUSION:
The District concludes that, although not in strict compliance with Appendix R,Section III.G.2, the Auxiliary Feedwater Pumps are adequately protected from a fire that could disable both trains. Modification of the system by relocation, or installation of a rated fire barrier, would not significantly enhance the fire protection features provided by the existing configuration.
Thus, the District requests an exemption to 10CFR50, Appendix R, Section III.G.2, for the existing configuration.
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RKEMPTION REQUEST 4 F.A. 69 AUXILIARY FEEDWATER VALVES - INTERVENING COMBUSTIBLES EKEMPTION REQUEST:
Per the provisions of'10CFR50.12, the District requests an exemption for Rancho Seco from the specific requirements of Appendix R,Section III.G.2,.
requiring one of the following forms of protection for the Auxiliary Feedwater Valves 1.
. Separation by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier.
7 2.
Separation by at least 20 feet of horizontal distance without intervening combustibles with fire detection and automatic suppression.
t 3.
Enclosure of cables and equipment and associated non-safety circuits of one redundant train in a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated fire barrier with fire detection and automatic suppression.
DESCRIPTION OF EXEMPTION:
1 The Auxiliary Feedwater Valves associated with "A" Train FV20528 and SFV20578 and those associated with "B" Train FV20527 and SFV20577 are all located in I
the same outdoor fire area with a horizontal separation of approximately 50 j
feet. However, intervening combustibles exist in the form of a four tier cable tray run.
The cable trays are provided with two fire stops at least 20 i
feet apart to separate the redundant trains.
There are no fire detection or automatic suppression systems installed in the area.
SAFE SHUTDOWN EQUIPMENT:
At least one train of Auxiliary Feedwater Valves are required to remain operable to achieve and maintain hot shutdown. Additionally, at least one train is required to achieve cold shutdown.
AREA DESCRIPTION:
Fire Area 69 consists of a 33,806 square foot, outside, fenced-in area which j
contains the Nuclear Service Yard equipment. The perimeter of this area 4
consists of an eight foot high block wall supporting a chain link fence and j.
adjoining Reactor and Auxiliary Building walls (see Figures 4 and 5).
The B Train. valves FV20527 and SFv20577 are located 43 feet north of the E-W center i
line of the containment and approximately ten feet from the containment wall l
at approximately 17 ft. elevation. The circuits to the B Train valves are routed in conduit and pass near a four tier cable tray run. At the closest point, this conduit is located approximately 12 inches below and two feet to
- the side of the lower cable tray. The valves themselves are located approximately eight feet horizontally from the lower cable tray run.
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Exemption Request 4 (Cont.) The A Train valves FV20528 and SFV20578 are located just south of the conteinment E-W center line about ten feet from the containment wall at elevation 24 feet. 8 inches. These valves are located five feet above the four tier cable tray run.
i The cable trays will contain two fire stops at least 20 feet apart between the A Train valves and B Train valves.
FIRE PROTECTION CAPABILITY:
There is no fire detection or automatic suppression system in the AFW valve part of this fire area. The area does have a fire hydrant and hose house, for manual suppression activities located approximately 60 feet to the northeast 4
i of the valve area.
FIRE HAZARD ANALYSIS:
The total fire loading in Fire Area 69 consists of approximately 4674 lbs of cable insulation, approximately 20 gallons of oil, 20 lbs of PVC, and 16 lbs of battery cases. This results in an average fire loading of 1,786 BTU /ft2, which if totally consumed would correspond to a fire of severity of 2 minutes on the ASTM E-119 standard time-temperature curve.
The two trains of Auxiliary Feedwater Valves are separated by approximately 50 feet of horizontal separation. The intervening combustibles consist of a four tier cable tray run.
The trays in this run are lightly loaded (from 5%-21%).
The upper tray is covered by a solid metal cover. These trays are provided with two fire stops (see Figure 7 for details of fire stops). These fire stops preclude the possibility of a single fire propagating in the cable trays from one train of AFW valves to the other.
The conduits and cables for the A Train could be damaged by a fire preventing remote control of valves SFV20528 and SFV20578.
However, as a result of the light loading, distance and geometry, and fire stops, the cable and conduit associated with the B Train valves SFV20527 and SFV20577 would not be disabled. Hot gases and heat associated with a fire would dissipate to the atmosphere. Since the valves, cables, and conduits are designed for outside service, they will not be disabled by fire suppression activities.
CONCLUSION:
The District concludes that the existing configuration provides adequate protection to prevent a single fire from disabling both trains of the Auxiliary Feedwater Valves. With the low fire loading in the overall outdoor area and the minimal loading of the intervening cable tray run, as well as geometry, a single fire will not disable both trains of Auxiliary Feedwater Valves. Therefore, hot and cold shutdown can be accomplished. Therefore, an exemption is requested from the technical requirement of 10CFR50, Appendix R, Section III.G.2, for the Auxiliary Feedwater valves.
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EXEMPTION REQUEST 5 F.A. 68 CABLES INSIDE CONTAINMENT, ELECTRICAL PENETRATION AREA - INTERVENING COMBUSTIBLES EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption for Rancho Seco from the specific requirements of Appendix R,Section III.G.2, which requires one of the following forms of protection for the redundant circuits inside containment:
1.
Separation by a horizontal distance of at least 20 feet without intervening combustibles or fire hazards.
2.
Fire detection and an automatic suppression system in the area.
3.
Separation by a noncombustible radiant energy shield.
1 DESCRIPTION:
J Redundant circuits associated with various safe shutdown components are routed inside containment. Although separated by a horizontal distance of at least 30 feet, intervening combustibles exist in the form of horizontal cable trays l
which have fire breaks in place. Additionally, although the Reactor Building has localized fire detection, automatic suppression capability does not exist.
SAFE SHUTDOWN EQUIPMENT:
The redundant circuits associated with this request are as follows:
S/G Level OTSG A OTSC B LT20501 LT20502 LT20501A LT20502A 1
At least one SG 1evel indication is required for hot and cold shutdown.
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Exemption Request 5 (Cont.) At least one pressurizer level transmitter is required for hot and cold shutdown.
RCS Cold Lea Temperatures A Loop B Loop TE21023A TE21024A TE21023B TE21024B TE21025C TE-21024C At least one cold leg temperature indication is required for hot and cold shutdown.
RCS Hot Lea Indication A Loop B Loop TE21029 TE21830 TE21033 TE21034 TE21031C TE21032C At leat one hot leg temperature indication is required for hot and cold shutdown.
RCS Pressure PT21042 PT21043 PT21092 PT21099 At least on RCS pressure indication is required for hot and cold shutdown.
RB Emergency Cooling Fans Emergency Cooler A Emergency Cooler B Emergency Cooler C Emergency Cooler D At least two of the four RB Emergency Coolers are required for hot and cold shutdown.
Neutron Indication ' (Source Ranae)
XE00005 XE00006 At least one source range indication is needed for cold shutdown only.
Exemption Request 5 (Cont.) AREA DESCRIPTION:
Fire Area 68 encompasses the entire Reactor Building.
The electrical penetration sector is located at the southern wall of the Reactor Bui' ding bounded by coordinates 162 degrees-45' and 220 degrees-12' and elevation 4'-0" through 39'-6".
In addition to the electrical penetrations, the area contains conduits and cable trays generally traversing west for Channels A and C, east for Channels B and D circuits and non-IE circuits traversing east and west on different levels of raceways. Electrical connections to devices inside the containment pass through this area with circuits at each penetration selected to give adequate separation distance between redundant trains. Circuit routing and penetrations used for alternate shutdown circuits are also selected to meet the separation requirement.
The Reactor Building walls are of concrete construction with a steel liner.
The volume of the Reactor Building is extremely large. The Reactor Coolant Pump Hotors are protected by an oil collection system.
See Figure 6 for a diagram showing physical relationship. Table 1 lists the associated circuits for each penetration.
The cables used inside containment exceed the requirements stipulated under IEEE 383 flame test procedure and pass the vertical flame test as specified in UL Publication #UL83 of IPCEA Standard S-19-81, Section 6.19.6.
FIRE PROTECTION SYSTEMS:
The electrical penetration sector has seven ionization detectors.
Portable l
extinguishers are available within the area and in adjacent areas.
There in no automatic suppression capability inside containment.
FIRE HAZARDS ANALYSIS:
Average fire loading in the Reactor Building is 39,817 BTU / square feet.
The Reactor Building is designated as Fire Area 68, and is divided into smaller sub-fire areas. The electrical penetration sector is contained within sub-Fire Areas 68-5, 68-6, and 68-8.
The fire loading within the electrical penetration sector is approximately 43,725 BTU / square feet. There are no combustibles in this sector other than cables. The only credible ignition source would be a large electrical fault, however, this potential is considered to be extremely remote.
Redundant circuits in the electrical penetration sector are separated by at least 30 feet of horizontal separation. Channel A and B circuits are routed in a~ combination of conduits and cable trays.
Channel C and D cables are routed in conduit.
Fire breaks are provided in the intervening cable trays to separate redundant trains or channels (see Figure 7 for details of fire stop).
l The penetrations are enclosed in metal housings which, although not rated, provide considerable protection. The electrical penetration area is approximately 30 feet above the Reactor Building floor.
l Exemption Request 5 (Cont.) Based on the lack of credible ignition sources, the probability of a fire occurring in this area is very low.
If a fire were to occur, it would propagate slowly due to the flame resistance of the cables. The fire breaks provide additional protection against the propagation of a fire between trains or channels. Thus, it is considered unlikely that a single fire will disable all redundant circuits associated with each function.
CONCLUSION:
The District concludes that the existing configuration provides adequate protection to prevent a single fire from disabling all redundant circuits associated with each required function. With the lack of ignition sources, the minor amount of intervening combustibles with cable tray fire breaks, and the physical separation provided, a single fire will not disable all redundant circuits associated with each function.
Therefore, hot and cold shutdown can be accomplished. Modification by rerouting the intervening combustibles, providing an automatic suppression system, or a radiant energy shield will not significantly enhance the fire protection features provided by the current configuration. Thus, the District requests an exemption to 10CFR50, Appendix R Section III.G.2, for the existing configuration.
Exemption Request 5 (Cont.) TABLE 1 CIRCUITS BY PENETRATION NUMBER Penetration Number Circuit H7RP03 TE21029 H7RPO4 RB Cooler B H7RP05 RB Cooler D H7RP17 XE00006 H7RP13 PT-21042 TE21023B TE21024B H7RP21 PT21099 LT20502 LT21503C TE21030 H7RP41 PT21043 LT20501A LT20502A LT21503D TE21024C TE21025C TE21033 H7RP57 TE21031C TE21032C H7RP59 RB Cooler A H7RP63 PT21092 LT20501 LT21503A LT21503B TE21034 H7RP64 RB Cooler C H7RP66 TE21023A TE21024A H7RP67 XE00005
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1 EXEMPTION REQUEST 6 F.A. RG1 AUXILIARY BUILDING ELECTRICAL PENETRATION AREA -
1 HOUR RATING OF CABLE FIRE BARRIER EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption for the containment electrical penetration assemblies in Fire Area RG1, the Auxiliary Building Penetration Area (former Fire Area 34). The specific requirements of Appendix R.Section III.G.2.c require enclosure of cable and associated non-safety circuits of one redundant train in a fire barrier having a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rating with fire detection and automatic suppression system in the fire area.
An exemption request for this area was submitted previously by the District's letter dated July 24, 1984. Changes noted below have been made as a result of the Appendix R re-evaluation.
Therefore, this exemption request supercedes our July 24, 1984 exemption request.
1 DESCRIPTION OF EXEMPTION:
RCS hot leg temperature and source range nuclear instrumentation are routed in rigid steel conduits, enclosed in I hour fire rated enclosures, and terminated at penetrations H7RP17 or H7RP21 (see Figure 8).
This modification complies with the requirements of Section III.G.2.c of Appendix R, with the exception of the metal housing enclosing penetration assemblies H7RP17 and H7RP21. This metal housing is part of the penetration assembly, and is not a fire rated enclosure.
SAFE SHUTDOWN EQUIPMENT:
The safe shutdown circuits of concern in this fire area are RCS hot leg temperature transmitters TE-21030 and TE-21034 and source range nuclear instrumentation XE00005 and XE00006.
AREA DESCRIPTION:
Fire Area RG1 consists of the following areas:
l 1.
Electrical Penetration Area / Chemical Storage Balcony (Sub-Fire Area RG1-34).
i 2.
Hot Machine Shop (Sub-Fire Area RG1-35).
4 j
3.
Waste Solidification Area (Sub-Fire Area RG1-39).
4.
Make-up Tank Room (Sub-Fire Area RG1-65).
5.
Air Conditioning Equipment Room (Sub-Fire Area RG1-22).
I, l
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Exemption Request 6 (Cont.) The walls, floor, and ceiling of the area are of 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated construction, except the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated construction for the north, south, and east walls of the duct shaft on the turbine deck level, and the south wall of the stairwell 6 (RB2) at grade level. The six inch expansion joint between the floor and ceiling slabs and the Reactor Building is 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated. The six inch expansion joints between the walls and the Reactor Building are not rated.
The exterior walls and the north wall to the Reactor Building are nonrated.
The north wall adjoining the Reactor Building (68) is concrete with an approximate thickness of 48 inches. The sample line shaft located by elevator 1 (61) has a concrete wall with an approximate thickness of 26 inches. The exterior walls are concrete with a minimum thich t, ass of 12 inches. The walls of the area adjoining the grade level corridor (36) and mezzanine level corridor (RM1) are concrete with a minimum thickness of 12 inches. The walls of the area bordering the toilet (64), storage area and stairwell 5 (47), and the yard area (69) are concrete with a minimum thickness of 12 inches. The walls of the area adjoining the elevator (61) and the electrical penetration room (28) are concrete with a minimum thickness of 12 inches. The walls of the area bordering stairwell 3 (72), stairwell 4 (RB2), and stairwell 6 (RB2) are concrete with a minimum thickness of 12 inches, except the south wall of stairwell 6, which is constructed of drywall partition with metal stude and plaster on each side. The south wall of the mezzanine level adjoining stairvell 1 (67) is concrete with an approximate thickness of 15 inches. The north, east, and south walls of the duct shaft on the turbine level are made of metal studs and gypsum board. The west wall of the duct shaft is concrete with an approximate thickness of 15 inches. The ceilings are concrete with a minimum thickness of 6 1/2 inches. The floor is concrete with an approximate thickness of 24 inches. The floor of the chemical storage balcony is concrete with an approximate thickness of 10".
Access to the area is through 1 1/2 hour rated doors from the grade level corridor (36), stairs 4 and 6 (RB2), elevator 1 (61) and stairwell No. 3 (72). A 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated door allows access to the corridor / stair to -47 foot elevation (47). Two 1 1/2 hour rated doors open to the mezzanine corridor (RM1). A nonrated rollup door opens to the exterior. The ventilation penetrations to the exterior and to Fire Areas 47 and 69 are not provided with fire dampers. The 54 inch diameter duct is not provided with fire dampers where it penetrates the floor to Fire Area RB2 and the west wall to Fire Area RM1. The 22 inch diameter duct penetration in the ceiling to Fire Area 28 is not provided with a fire damper.
Ventilation duct penetrations to Fire Areas
- 36. RM1 and RT1 are provided with 1-1/2 hour rated fire dampers. One duct to RT1 is provided with a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire damper.
Electrical penetration seals to Fire Areas 36, 64, and RM1 are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated. The electrical penetration seal in the floor is I hour rated. Mechanical penetration seals to Fire Area 47 are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated. Mechanical penetrations to all other adjacent fire areas are 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated. An opening of approximately 7 feet by 2 feet adjoining elevator 1 (61) is covered with nonrated 16 gage sheet steel.
4 Exemption Request 6 (Cont.) FIRE PROTECTION CAPABILITY:
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The area contains a wet pipe sprinkler system for area-wide suppression coverage, except for room 114.
Ionization detectors, located within the area provide early warning alarm in the Control Room. Two hose stations are located within the area and additional hose stations are available in adjacent i
areas. Portable extinguishers are available within the area and in adjacent areas.
FIRE HAZARD ANALYSIS:
The fire loading for RG1 consists of a composite of the fire loading for the j
sub-fire areas. These loadings and the equivalent severities are as follows:
Equivalent Fire Areas Fire Load Fire Duration 22 11,033 BTU /FT 2
.14 hrs t
34 21,489 BTU /FT 2
.27 hrs 35 971 BTU /FT 2
.01 hrs 3
39 42,841 BTU /FT 2
.54 hrs 65 0 BTU /FT 2 0 hrs j
This results in an average fire duration for the total area of 13.8 minutes j
(ASTM E-119).
i The safe shutdown circuits for Train A Source Range Flux Indication XE00006 and Train B Reactor Coolant System Hot Les Temperature Transmitter TE21030 which are enclosed in the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> barrier terminate at penetrations H7RP17 or H7RP21.
Both these penetrations are close to the floor level and more than l
ten feet below the ceiling. Considering the large volume of this area, in the event of fire, the heat and the hot gases which could cause damage at the penetrations will collect near the ceiling away from the penetrations. The enclosure around the penetration assemblies H7RP17 and H7RP21 are metal and will provide adequate protection for the cables.
s CONCLUSION:
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The District concludes that, although not in strict compliance with Appendix R Section III.G.2.c. the metal enclosure around penetrations H7RP17 and
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M7RP21 provides adequate protection for the safe shutdown circuits.
Modification to the electrical penetration assembly or testing of the installed configuration to obtain a fire rating will not significantly enhance the fire protection features provided by the current configuration.
Therefore, the District requests an exemption to Appendix R. Section 111.G.2.c from the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rating requirement for the penetration assembly configuration of penetrations H7RP17 and H7RP21.
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EXEMPTION REQUEST 7 FIRE AREA RB1 AUXILIARY BUILDING (-)20'-0" OPENING IN FIRE BARRIER EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption for Rancho Seco from the specific requirements of Appendix R,Section III.G.2(a),
to the extent that it requires separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rating.
DESCRIPTION OF EXEMPTION:
Several former fire areas have been combined into two revised Fire Areas RBI and RB2, located in the Auxiliary Building at elevation (-)20'-0".
An open doorway from corridor 045 (Sub-Fire Area RB1-50) to corridor 036 (Sub-Fire Area RB2-46) penetrates the rated fire boundary between RBI and RB2 (see Figure 9 at column lines V and 8.7).
The opening is approximately 6 feet wide and 20 feet high. A 32 inch diameter exhaust air duct passing above the 6' x 20' opening is not provided with a rated fire damper.
Redundant safe shutdown equipment and circuitry is contained in Fire Areas RBI and RB2.
SAFE SHUTDOWN EQUIPMENT:
The safe shutdown circuits / components of concern in Fire Areas RBI and RB2 are as follows:
o RBI Train A and B for Makeup Pump P-236 and associated lube oil pump Train A BWST Isolation Valve SFV-25003 Train A NSW Valves SFV-26017, SFV-26019, SFV-50005, SFV-50009, SFV-50007, and SFV-50011 Train A Decay Heat System Valves SFV-26005, SFV-26037, and SFV-26039 o RB2 Train B HPI Pump P-238B and associated lube oil pump Train B normal feed to Makeup Pump P-236 and associated lube oil pump Train B normal feed to Makeup Pump room cooler A-529B Train B llPI Pump Room Cooler A-529C AREA DESCRIPTION AND CONSTRUCTION:
Fire Area RBI consists of the following Sub-fire areas at the (-)20'-0" elevation:
Exemption Request 7 (Cont.) 1.
West Containment Penetration Valve Area (Sub-Fire Area RB1-49) 2.
East Containment Penetration Valve Area (Sub-Fire Area RB1-50) 3.
Radwaste Air Supply Fan Room (Sub-Fire Area RB1-51) 4.
Makeup Pump Room (Sub-Fire Area RB1-58) 5.
Seal Return Cooler Room (Sub-Fire Area RB1-52) 6.
Spent Resin Tank Room (Sub-Fire Area RB1-60)
The area is below grade. The walls and ceiling of the area adjoining other fire areas are of 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated construction.
The seal in the expansion joint between the ceiling and the Reactor Building is 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated.
The Reactor Building wall is not rated. The floor over the decay heat system pump rooms (56, 57) is of 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated construction.
The north wall adjoining the Reactor building (68) is concrete with an approximate thickness of 72 inches.
The walls of the radwaste air supply fan room are concrete with a minimum thickness of 15 inches. The north wall of the spent resin tank area is concrete with a minimum thickness of 24 inches.
The walls adjoining Fire Area RB2 are concrete with a minimum thickness of 18 inches. The south wall bordering the corridor and stairwell (47) is concrete with an approximate thickness of 30 inches.
The walls adjoining the High Pressure Injection Pump A Room (48) are concrete with an approximate thickness of 18 inches. The column L (west) wall is concrete with an approximate thickness of 30 inches. The ceiling is concrete with a minimum thickness of 24 inches. The floor above areas 56 and 57 is concrete with a minimum thickness of 18 inches. The floor in the rest of the area is a concrete base slab. A six inch expansion joint separates the ceiling from the Reactor Building wall.
Access to the area is through a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated door from the corridor (47) and an open walkway 6' x 20' from the east corridor in area RB2. A 3/4 hour rated door opens to the Train A High Pressure Injection Pump Room (48) and a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated door opens to the Train B High Pressure Injection Pump Room (RB2).
The ventilation duct penetration to the High Pressure Injection Pump "B" room (RB2) is provided with a 1 1/2 hour rated fire damper.
The ventilation opening in the floor to Fire Area 56 is not provided with a rated fire damper. The ventilation duct in the open corridor to Fire Area RB2 and the 12 inch diameter duct in the ceiling to the yard area (69) are not provided with fire dampers. The duct to the exterior through the ceiling is not provided with a fire damper. Electrical penetration seals in the south wall to Fire Area RB2 have a minimum rating of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Electrical penetration seals in the floor are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated. Electrical and mechanical seals to adjacent area 47 are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated. The electrical penetration seal in the ceiling to area RG1 is I hour rated. Mechanical penetration seals to the remaining fire areas are 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated.
The ceiling height of Fire Area RBI is approximately 20 feet.
Exemption Request 7 (Cont.) Fire Area RB2 consists of the following sub-fire areas at the (-)20'-0" elevation:
1.
Waste Gas Compressor Room (Sub-Fire Area RB2-40) 2.
Waste Gas Decay Tank Room (Sub-Fire Area RB2-41) 3.
Miscellaneous Waste Gas Condensate Room (Sub-Fire Area RB2-42) 4.
Deboration Ion Exchange and Miscellaneous Waste Demineralizer Room (Sub-Fire Area RB2-43) 5.
Miscellaneous Waste Concentrator and Tank Room (Sub-Fire Area RB2-44) 6.
Boric Acid Evaporator Room (Sub-Fire Area RB2-45) 7.
Main Corridor - Below Grade (Sub-Fire Area RB2-46) l 8.
Ion Exchange Valve Area (Sub-Fire Area RB2-53) 9.
Miscellaneous Waste Filter Room (Sub-Fire Area RB2-54)
- 10. Tank Rooms - Below Grade (Sub-Fire Atea RB2-55)
- 11. High Pressure Injection Pump Room B (Sub-Fire Area RB2-59)
- 12. Miscellaneous Waste Tank Room (Sub-Fire Area RB2-66)
CONSTRUCTION - FIRE AREA RB2 The area is below grade. The walls and ceiling adjoining other fire areas are of 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated construction. The exterior walls are concrete with a minimum thickness of 15 inches. The walls adjoining the containment penetration area (RB1) are concrete with a minimum thickness of 18 inches. The walls bordering the cable tunnels (18, 19, 81) are concrete with a minimum thickness of 18 inches. The walls adjoining the stairwell (47) are concrete with a minimum thickness of 21 inches. The floor above the reactor coolant drain tank (RB1) is of 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated concrete construction with an approximate thickness of 24 inches. The remaining floor is concrete base slab. The walls and ceiling of stairwells 4 and 6 at grade level are concrete with an approximate thickness of 12 inches, except for the south wall of stairwell 6, which is of 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated drywall partition construction. The ceiling of stairvell 6 is concrete with an approximate thickness of 10 inches.
Access to the area is through 1 1/2 hour rated doors from Fire Area RG1 through stairwell 4 or stairwell 6.
Two 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire doors communicate with the stairwell (47) and the makeup pump room (RB1). North of the Train B high pressure injection pump room, an open corridor communicates with Fire Area RBl. A ventilation duct penetration communication from the Train B high pressure injection pump room to corridor 045 (RB1) is provided with a 1 1/2 hour rated fire damper. The ventilation penetration in the north wall to Fire
i Exemption Request 7 (Cont.) Area 47 is provided with a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire damper. The 42 inch diameter duct in the west wall to Fire Area 47 is not provided with a fire damper. A ventilation duct routed through the open end of corridor 045 does not have a fire damper.
The 54 inch diameter ventilation duct communicating with Fire Area RG1 through the ceiling is not provided with a rated fire damper. Electrical penetration seals in the north wall have a minimum rating of I hour.
Electrical penetration seals to Fire Areas 19 and 47 are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated. Mechanical penetration seals in the west wall are 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated. Mechanical penetration seals to Fire Area 47 are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated.
Remaining mechanical penetration seals are 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rated.
1 The ceiling height of Fire Area RB2 is approximately 20 feet.
FIRE PROTECTION SYSTEMS:
Fire protection for Fire Area RB1 consists of ionization smoke detectors and two fire hose stations. A wet pipe sprinkler system is provided in corridor (045) near the east boundary of RBI (see Figures 9 and 10). One fire hose station is located in the west containment penetration valve area (Sub-Fire Area RB1-49) and the other fire hose station is located in the east containment penetration valve area (Sub-Fire Area RB1-50). Portable extinguishers are available within the area and in adjacent areas RB2 and 47.
Fire protection for Fire Area RB2 consists of ionization smoke detectors (in corridors and Train B HP1 Pump Room), a wet pipe system in corridor 015 and the north end of corridor 036, fire hose stations, and portable extinguishers within the area and in adjacent areas.
FIRE RAZARDS ANALYSIS:
The makeup pump P-236, lube oil pump P-236/ LOP, pump room cooler A-529B and their associated normal and alternate (Train B and Train A) power and control circuits are located in Fire Area RBl.
Fire Area RB1 also contains both Train A and B equipment and circuitry for the Borated Water Storage Tank Isolation Valve, Nuclear Service Water Valves, and Decay Heat System Valves required for safe shutdown. The circuitry for the redundant Train A HPI pump P-238A, lube oil pump P-238A/ LOP, and HPI pump room cooler A-529A are not routed through either area RB1 or RB2, hence will remain available.
The redundant Train B HPI pump P-238B, lube oil pump P-238B/ LOP, and pump room cooler A-529C and their associated power and control circuits are located in Fire Area RB2. Fire Area RB2 also contains Train B normal feed to makeup pump P-236, lube oil pump P-236/ LOP, pump room cooler A-5298, as well as Train B equipment and circuitry for the Borated Water Storage Tank Isolation Valve, Nuclear Service Water Valves, and Decay Heat System Valves required for safe shutdown.
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Exemption Request 7 (Cont.) There is a minimum of approximately 40 feet of separation between the Train A alternate feed circuitry to the makeup pump (RB1) and the Train B HPI circuitry (RB2), based on a path from "A" to "B" shown in Figure 9.
Note that this minimum distance takes no credit for the presence of concrete walls unless they are part of the maintained fire area boundary. There is approximately 75 feet of separation between these circuits based on a path through the corridors from "C" to "D" shown in Figure 9.
The "X" indicates the location of the opening between Fire Areas RBI and RB2.
Loss of the Train B BWST Valve, NSW Valves, and DHR Valves is to be expected for a fire in either RB1 or RB2. Train A equipment and circuitry for these valves is located in the area of RBI west of col. line P.
A concrete / concrete block wall which is not maintained as a fire boundary separates this portion of RB1 from the rest of the area.
The in-situ combustible loading in Sub-Fire Area RB1-50 adjacent to the 6' x 20' opening to Sub-Fire Area RB2-46 is 11,397 Btu /ft2, which corresponds to an 8.4 minute fire duration (ASTM E-119).
The fire load consists of cabling, plastics, and rubber. The in-situ loading in Sub-Fire Area RB2-46 is 67,513 Btu /f t2, which corresponds to a fire duration of approximately 50 l
minutes (ASTM E-119).
The fire load consists of cabling, Class A materials, plastics, acetylene, and rubber. The local combustible loading in corridor 036 (RB2-46) north of column line 11 is 13,856 Btu /f t2 (equivalent fire duration of about 10 minutes). Storage of transient combustibles within 20 feet of the 6' x 20' opening is prohibited by plant housekeeping procedures unless compensatory measures are provided.
A vet pipe sprinkler system is provided in corridor 045 (RB1-50) near the 6' x 20' opening (see Figure 9).
Wet pipe sprinklers are installed above the cable trays in corridor 036 (RB2-46).
Additional loss of redundant safe shutdown capability due to fire propagation between Fire Areas RBI and RB2 because of the walkway opening in the barrier is not expected due to the low local combustible loading, the presence of ionization detectors in the corridors to provide an alarm in the control room for prompt response by the fire brigade, and the wet pipe sprinkler protection at the opening. Redundant safe shutdown circuits are separated by sufficient distance around corners of the corridors that a tortuous path is provided to prevent flame and heat from causing damage to both.
Because of the large volumes of Fire Areas RBI and RB2 products of combustion would be diluted by ambient air conditions and, therefore, would not present a threat to the redundant division.
Exemption Request 7 (Cont.) CONCLUSION:
The District concludes that, although not in compliance with Appendix R.
Section III.G.2(a), the extension of the fire rated boundary to include the l
cpening of Fire Area RB1 would not significantly enhance the level of fire protection provided by the existing configuration. Therefore, the District requests an exemption to 10CFR50 Appendix R, Section III.G.2(a), to the extent that it requires the separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rating.
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EXEMPTION REQUEST 8 NUCLEAR SERVICE RAW WATER PUMPS -
LACK OF SUPPRESSION AND DETECTION EXEMPTION REQUEST:
Per the previsions of 10CFR50.12 the District requests exemption for Rancho Seco from the requirements of Appendix R,Section III.G.2(b), to the extent that it requires fire detection and automatic suppression for the Nuclear Service Raw Water (NSRW) Pumps when separated by more than 20 feet horizontal distance with no intervening combustibles.
DESCRIPTION OF EXEMPTION:
i The NSRW pumps are located outside, within the confines of the security fence. They are redundant to each other and are necessary for cooling the plant down during normal and abnormal conditions. The pumps are separated by approximately 430 feet of open space with no intervening combustibles.
Power supplies snd associated circuits are routed under ground except in the immediate vicinity of the pumps. No 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barrier or automatic suppression or detection is provided because of large separation distance and insignificant combustible loading near and between the pumps.
SAFE SHUTDOWN REQUIREMENT:
Shutdown Systems 1.
Nuclear Service Raw Water Pump (P-427A) - Train "A" 2.
Nuclear Service Raw Water Pump (P-472B) - Train "B" Either one of the above systems are required for plant shutdown.
AREA DESCRIPTION:
Located approximately 180 feet directly north of the hyperbolic cooling towers are the NSRW pumps and spray ponds.
Each spray pond is approximately 57,800 square feet and there is one pump per pond.
The east spray represents the B train system and the west spray pond represents the A Train system (see Figure 11). Located in the south end of the spray pond are the corresponding NSRW pumps P-472A and B.
As shown on the attached drawing, there is approximately 430 feet between the two raw water pumps.
The area between the two pumps is an open (outside) area paved with asphalt. Each pump is housed in a locked steel security enclosure with louvered siding on all four sides. This affords I
some protection against accidental or intentional mishap.
FIRE PROTECTION SYSTEMS:
The two NSRW pumps are located in a remote, open air location separated by 430 feet with no combustible fire loads in between. No detection or suppression is provided.
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> Exemption Request 8 (Cont.) FIRE HAZARD ANALYSIS:
There is no casual traffic in the area of the raw water pumps nor is there any significant fire load. Electrical motor windings and the small amount of lubricating oil in the pumps are considered.to be negligible and are confined within the locked steel enclosure protecting each of.the NSRW pumps.
CONCLUSION:
The District' concludes that, although not in compliance with Appendix R, Sectiun III.G.2(b), the Nuclear Service Raw Water pumps are adequately protec'ted from a fire disabling both trains due to 430 feet separation with no intervening combustibles and the open air location. Modifications to add suppression and/or detection would not result in a reduction in risk over the existing configuration. Therefore, the District requests an exemption to Appendix R.Section III.G.2(b) for the Nuclear Service Raw Water pumps to the extent that it requires automatic suppression and detection.
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EXEMPTION REQUEST 9 NUCLEAR SERVICE ELECTRIC BUILDING ROOF LACK OF FIRE DETECTION & AUTOMATIC SUPPRESSION EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption from the specific requirements of Section III.C.2 of Appendix R to 10CFR50 for the Nuclear Service Electric Building (NSEB) roof area which requires one of the following forms of protection for the NSEB essential air-condition compressor / condensing units (U-503A and B):
1.
Separation by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier.
2.
Separation by at least 20 ft. of horizontal distance without intervening combustibles with fire detection and automatic suppression.
3.
Enclosure of cables and equipment and associated non-safety circuits of one redundant train in a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated fire barrier with fire detection and automatic suppression.
DESCRIPTION OF EXEMPTION:
Both trains of the NSEB essential HVAC air-conditioning compressor / condensing units (U-503A and B) are located in the same fire area. Although separated by greater than 40 feet of horizontal distance without intervening combustibles, there is no fire detection or automatic suppression in this area.
SAFE SHUTDOWN REQUIREMENT:
The NSEB essential HVAC is required to protect essential electrical equipment in the NSEB from excessive operating temperatures (i.e., provides area cooling). Thus the NSEB essential HVAC system is required for hot and cold shutdown conditions and at least one train is required to remain operable.
AREA DESCRIPTION:
The NSEB roof area consists of an area of 4055 square feet. On the western portion of the roof there is one normal air conditioning unit (U-501A) which serves the west side of the building and the A Train essential air conditioning compressor / condensing unit (U-503A). On the eastern portion of the NSEB roof there is one normal air conditioning unit (U-501B) which serves the east side of the building and the B Train essential air conditioning compressor / condensing unit (U-501B). Refer to Figure 12 for a diagramatic layout of the NSEB roof area. The construction of the NSEB roof consists of a
-2 ft.-thick concrete slab. The low portion of the slab is normal high density concrete while the upper 4" to 10" is light weight concrete and provides the roof slope. This roof slab is covered by two layers of 15/8" rigid insulation topped off with a fiberglass roll roofing. Wooden nailing strips which form part of roofing system below the fiberglass roll roofing, are fire retardant pressure treated. The roof covering and method of installation result in a Class A roof covering which will not support combustion. The roof I
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Exemption Request 9 (Cont.).
is penetrated by several undampered HVAC ducts and rain capped ceiling vents which prevent the entire roof from being considered a rated fire barrier.
However, the roofing section which is immediately over the cable rooms A and B (rooms 364 and 365), battery rooms A and B (rooms 370 and 371) as well as the corridor (room 361) are unbroken and constitute a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated barrier between the roof and these individual fire areas.
The western portion of the roof over the Computer Room "A" (room 363), is penetrated by one normal A/C supply duct (84" x 27") and one normal A/C return duct (36" x 75").
The supply duct is 12 gauge sheet steel lined with 1" of fiberglass, the return duct is 14 gauge steel, unlined.
The gap between the ducts and the sides of the roof opening is approximately 1".
At the top of the duct opening are substantial concrete curbs around the ducts. The return duct is protected from rain ingress by a metal hood attached to the duct which maintains the 1" gap. The supply duct curb opens into the underside plate of the normal A/C unit and is in effect a dead end.
The eastern portion of the roof over the Computer "B" Room has the same construction as that over the Computer "A" Room.
The conduits which power the normal HVAC units are located on the north side of the units and thus are separated from the essential A/C units.
The conduits which power the essential A/C units are located on the unit's side nearest the edge of the roof and are shielded by the casing of the respective unit from the rest of the roof area.
Each normal HVAC unit contains approximately 7 1/2 gallons of lubricating oil with a flash point of 335 degrees F.
The compressor units are hermetically sealed with a low probability of leakage. However, in the event of a leak, the compressors will shut down from loss of freon with the oil leakage collecting in the casing pans which drain te the side of the roof. The drain from each normal HVAC casing is piped to discharge near the roof edge on its side of the building. This assures maximum separation of any oil spill from I
the redundant train. There is no potential ignition source near the oil drain area.
FIRE PROTECTION SYSTEMS:
There is no fire detection or fire suppression installed on the NSEB roof.
Two 10 lb. fire extinguishers are available on the 40' elevation.
FIRE HAZARDS ANALYSIS:
The fire loading in the NSEB roof area consists of approximately 15 gallons of lubricating oil with negligible quantities of cable insulation. This results in an average fire loading of 501 BTU per square foot which if totally consumed would correspond to a fire severity of less than 1 minute on the ASTM l
E-119 standard time-temperature curve.
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Exemption Request 9 (Cont.) Based on the low fire loading in the area and absence of significant ignition source, the potential for a fire occurring is extremely remote. However, if a fire occurred it would be of short duration and small intensity. Due to the open nature of the outside area, any products of combustion as well as heat produced would immediately dissipate to the atmosphere. The physical separation of the redundant trains as well as the construction material and configuration would prevent damage to both trains in a single exposure fire.
CONCLUSION:
The Districts concludes that, although not in strict compliance with Appendix R,Section III.G.2, the redundant NSEB essential air conditioning compressor /condensor units are adequately protected from a fire disabling both trains. Modification by relocation, installation of a rated barrier, or addition of detection and suppression would not significantly enhance the fire protection features provided by the existing configuration. Thus the District requests an exemption to 10CFR50, Appendix R, Section III.G.2 for the existing i
configuration of the NSEB roof, i
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EXEMPTION REQUEST 10 t
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AUXILIARY BUILDING ROOF FIRE DETECTION AND AUTOMATIC SUPPRESSION i
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EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption from the l
specific requirements of 10CFR50, Appendix R.Section III.G.3 which requires fire detection and automatic suppression for the auxiliary building roof area i
(Fire Area 74).
i 3
i DESCRIPTION OF EXEMPTION:
Both trains of essential Control Room HVAC are located in. the same fire area.
j Since both trains of essential Control Room HVAC share a common duct, j
separation as required by Appendix R.Section III.G.2 is impractical.
If a j
fire on the Auxiliary Building roof damaged both trains of the Control Room i
HVAC, the loss of HVAC could require the evacuation of the Control Room.
j Alternate shutdown is being provided for the Control Room area since a fire in j
the Control Room could also require evacuation of the Control Room. Thus, the Auxiliary Building roof area is considered an area requiring alternate i
shutdown and requires fire detection and automatic suppression per 10CFR50, Appendix R.Section III.G.3.
No area fire detection or automatic suppression is provided in this area.
l SAFE SHUTDOWN REQUIREMENTS:
L i
At least one train of the essential Control Room HVAC is required to ensure i
habitability of the Control Room. Since alternate shutdown is being provided j
for the Control Room area, loss of the essential Control Room HVAC will require that the alternate shutdown capability for a fire in the Control Room be utilized for a fire on the Auxiliary Building roof.
Thus the loss of both 3
trains of essential Control Room HVAC could require use of Control Room alternate shutdown capability.
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FIRE AREA DESCRIPTION:
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Fire Area 74 consists of an unenclosed outside area on the Auxiliary Building roof with a floor area of 17,702 square feet (see attached figure 14). The j
roof construction is 6 1/2" and 12" concrete with a light weight concrete i
cover of variable thickness. The roof slab is covered by two layers of 1 5/8" rigid insulation topped off with a fiberglass roll roofing. Wooden nailing
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strips which form part of-the roofing system below the fiberglass rool roofing j
1 are fire. retardant pressure treated. The roof covering and method of I
installation results in a class A roof covering which will not support j
combustion.
Access to the roof area is through the Number 2 stairwell exit enclosure with a 1 1/2 hour rated door provided with a security lock and door position j
switch. There are numerous NVAC duct penetrations through the roof with no fire dampers.
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Exemption Request 10 (Cont.) The combustible inventory on the roof area consists of 15 gallons of lubricating oil in the compressor casings of the refrigeration condensing units (7.5 gallons / compressor) and 2024 pounds of charcoal in the filtration units (1012 lbs/ unit). This charcoal is totally enclosed in filter canisters. This results in a fire loading of 703 BTU / square foot corresponding to less than a 1 minute fire.
Since the roof is not an enclosed room, the maximum fire severity would occur as a transient condition.
The peak temperature will be localized at the location of the combustible material since the heat dissipates into the atmosphere immediately in the absence of an enclosed space.
FIRE PROTECTION SYSTEMS:
There are no area detection or suppression systems in the fire area.
Local heat detectors are provided in the charcoal filter housing.
Portable CO2 extinguishers and a fire hose station are located in the turbine level corridor (FA RTI).
FIRE HAZARD ANALYSIS:
The total fire loading in Fire Area 74 consists of 15 gallons of lubricating oil and 2024 pounds of charcoal. This results in an average fire loading of 703 BTU / square foot, which corresponds to a 1 minute fire. Electrical cables are routed in conduit and do not contribute to the combustible inventory. The combustible inventory is enclosed in a Seismic Category 1 structure.
This area is not used for routine traffic or storage of combustible materials and hence transient combustibles are not of concern.
Since the combustible inventory is enclosed within Seismic Category 1 structures and is not exposed to an external ignition source, the probability of a fire occurring is extremely remote.
Based on the nature of the combustibles and the outdoor unenclosed area, if a fire occurred it would be of short duration with heat and combustion products rapidly dissipating to the atmosphere. Since the area is outside and subject to rain, no damage is expected to result from normal fire suppression activities.
CONCLUSION:
i The District concludes that although not in strict compliance with Appendix R.
Section III.G.3, the Control Room HVAC units are adequately protected from a fire that could disable both trains. Modification by installation of fire detection and automatic suppression would not significantly enhance the fire protection features provided by the existing configuration. Thus, the District requests an exemption to 10CFR50, Appendix R, Section III.G.3 for the existing configuration.
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EXEMPTION REQUEST 11 FA 69 NUCLEAR SERVICE WATER PUMPS FIRE DETECTION AND AUTOMATIC SUPPRESSION EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption for Rancho Seco from the specific requirements of Appendix R, _ Section III.G.2, requiring one of the following forms of protection for the redundant Nuclear Service Water Pumps:
1
- 1. ' Separation by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier.
2.
Separation by at least 20 feet of horizontal distance without intervening combustibles with fire detection and automatic suppression.
3.
Enclosure of cables and equipment and associated non-safety circuits of one redundant train in a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated fire barrier with fire detection and automatic suppression.
DESCRIPTION OF EXEMPTION:
c The redundant Nuclear Service Water Pumps are located in the same fire area.
The pumps are separated by approximately 55 feet with no intervening combustibles. Power circuits to the pumps are routed underground, in separate conduits, duct banks, and manholes except in the immediate vicinity of the pumps. Although the redundant trains are separated by approximately 55 feet without intervening combustibles, no fire detection or automatic supression is provided.
SAFE SHUTDOWN REQUIREMENT:
At least one train of Nuclear Service Water is required to be operable in order to achieve and maintain hot and cold shutdown conditions.
FIRE AREA DESCRIPTION:
Fire Area 69 is an outside, fenced-in area which contains the Nuclear Service Yard equipment. This 33,806 square foot area is surrounded on three sides by an unrated, 8 foot high, cinder block wall supporting a chain link fence. The remaining portion of the perimeter consists of he adjoining Reactor and Auxiliary Building walls.
i Located in the eastern portion of this area are the Nuclear Service Water Pumps. The pumps are separated by approximately 55 feet without intervening combustibles. Additionally, the 40 foot diameter Borsted Water Storage Tank (T-250) is located between the pumps (see Figure 13).
FIRE PROTECTION SYSTEMS:
There is no fire detection or automatic suppression in the Nuclear Service Water Pumps part of this fire area. Manual fire fighting equipment is located within the fire area.
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Exemption Request 11 (Cont.) FIRE HAZARDS ANALYSIS:
The total fire loading in Fire Area 69 consists of approximately 20 gallons of oil, approximately 467 pounds of cable insulation, 20 lbs of PVC, and 16 lbs of battery cases.
This results in an average fireloading of 1786 BTU / square foot, which if totally consumed would correspond to a fire severity of 2 minutes on the ASTM E-119 standard time-temperature curve.
The cables for each pump are routed underground in separate conduits, duct banks and manholes. Additionally, the pumps are separated by the Borated Water Storage Tank which would act as a radiant heat shield.
Based on the lack of combustibles in the immediate area of the pumps as well as a lack of ignition source, the probability of a fire occurring is extremely remote. Since the pumps are separated by approximately 55 feet and the Borated Water Storage Tank, a single fire involving one pump would not damage the redundant pump. Since the area is outside and unencl sed, any products of combustion and heat produced by a fire would immediately dissipate to the atmosphere. Since the area is located outside and subject to rain, no damage is expected to result from normal fire suppression activities.
CONCLUSION:
The District concludes that, although not in strict compliance with Appendix R,Section III.C.2, the Nuclear Service Water Pumps are adequately protected against a fire disabling both trains. Modification of the system by relocation, installation of a rated barrier or addition of detection and suppression would not significantly enhance the fire protection features provided by the existing configuration.
Thus the District requests an exemption to 10CFR50, Appendix R, Section III.G.2 for the existing configuration.
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EXEMPTION REQUEST 12 FA 74 NUCLEAR SERVICE COOLING WATER SURGE TANKS FIRE DETECTION AND AUTOMATIC SUPPRESSION EXEMPTIOli REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption for Rancho Seco from the specific requirements of Appendix R Section III.G.2, which requires one of the following forms of protection for the redundant Nuclear Service Water Surge Tank Level Switches and circuits located on the Auxiliary Building roof:
1.
Separation by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier.
2.
Separation by at least 20 feet of horizontal distance without intervening combustibles with fire detection and automatic suppression.
3.
Separation by a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated barrier with detection and automatic suppression.
DESCRIPTION OF EXEMPTION:
The Nuclear Service Water Surge Tanks are located on the Auxiliary Building roof. The associated level switches and circuits are separated by approximately 40 feet of horizontal separation with no intervening combustibles. Although separated by greater than 20 feet without intervening combustibles, no area fire detection or automatic suppression is provided.
SAFE SHUTDOWN REQUIREMENT:
At least one train of the Nuclear Service Cooling Water is required to remain functional to achieve and maintain hot and cold shutdown conditions. A fire induced short in the surge tank level switch circuit could trip the associated pump. Thus at least one train of Nuclear Service Water Surge Tank Level instrumentation is required.
FIRE AREA DESCRIPTION:
Fire Area 74 consists of an unenclosed outside area on the Auxiliary Building roof with a floor area of 17,702 square feet (see Figure 14). The roof construction is 6 1/2" and 12" concrete with a light weight concrete cover of variable thickness. The roof slab is covered by two layers of 15/8" rigid insulation topped off with a fiberglass roll roofing. Wooden nailing strips which form a part of the roofing system below the fibergalas roll roofing are fire retardant, pressure treated. The roof covering and method of installation result in a Class A roof covering which will not support combustion.
Exemption Request 12 (Cont.),
l j
Access to the roof area is through the Number 2 stairwell exit enclosure with a 1 1/2 hour rated door provided with a security lock and door position switch. There are numerous HVAC duct penetrations through the roof with no fire dampers.
I The tanks are located on the south central portion of the open roof area of i
the Auxiliary Building (FA 74). They are separated on the east, south, and west sides by a metal louvered screen wall. Access from the north is i
prevented by a combination of louvered screen walls and the esential Control Room HVAC. The resulting enclosure is approximately 70 x 30 feet with the only access through a short section of the west screen.
j FIRE PROTECTION SYSTEMS:
There are no area detection or suppression systems in the fire area.
Local
?
I heat _ detectors are provided in the charcoal filter housings. Portable l
extinguishers and a fire hose station are located in the turbine level corridor (FA'RTI).
FIRE HAZARDS ANALYSIS:
The total fire loading in Fire Area 74 consists of 15 gallons of lubricating oil and 2024 pounds of charcoal. This results in an average fire loading of 703 BTU / square foot, which corresponds to less than a 1 minute fire (ASTM E-119). Electrical cables are routed in conduit and do not contribute to the combustible inventory.
The comboatible inventory is enclosed in a Seismic Category 1 structure. This area is not used for routine traffic or storage of combustible materials and hence transient combustibles are not of concern.
Since the combustible inventory is enclosed within Seismic Category 1 structures and is not exposed to an external ignition sou.ce, the probability of a fire occurring is extremely remote.. Based on the nature of the combustibles and the outdoor unenclosed area, if a fire occurred it would be of short duration with heat and combustion products rapidly dissipating to the atmosphere. Since the area is outside and sabject to rain, no damage is expected to result from normal fire suppression activities.
CONCLUSION:
(
The District concludes that, although not in strict compliance with Appendix R Section III.G.2, modification by relocation, protected by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated barrier, or addition of detectors and automatic suppression will not significantly enhance the level of fire protection provided by the existing configuration. Therefore, the District requests an exemption to 10CFR50, Appendix R, Section III.G.2 to the extent it requires detection and automatic suppression protection the redundant Nuclear Service Cooling Water Surge Tank level for switches and circuits.
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EXEMPTION REQUEST 13 I.
FIRE AREA 1 CONTROL AND COMPUTER ROOM LACK OF AUTOMATIC FIRE SUPPRESSION EXEMPTION REQUEST:
Per the provisions of 10CFR50.12, the District requests an exemption from the specific requirements of Appendix R,Section III.C.3, to the extent that it requires a fixed fire suppression system in areas requiring alternative shutdown capability.
DESCRIPTION OF EXEMPTION:
Alternative shutdown capability is provided for the Control and Computer Room, Fire Area 1.
Ionization detection is provided in the Computer Room and within the Computer and Control Room panels. A wet pipe sprinkler system is provided in the Shift Supervisor's office, the conference room, the kitchen and toilet, and corridor 344. However, area-wide suppression is not provided.
SAFE SHUTDOWN EQUIPMENT:
This fire area contains safe shutdown circuitry for the following:
RCS Instrumencation Makeup System j
Main Steam System
~
Steam Generator Irstrumentation i
Feedwater System - Auxiliary Feedwater System Decay Heat Systen Nuclear Cooling Water System j
Nuclear Raw Water Cystem Essential HVAC Emergency Generator System i
Electrical Distribution System (4160V, 480V, and 120V AC) r Altenative shutdown capability has been provided for this area.
AREA DESCRIPTION AND CONSTRUCTION:
The interior walls, floors, and ceiling of the area are of 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated construction. The portion of the south wall to the exterior is nonrated. The walls adjoining Fire Area RT1 are concrete with an approximate thickness of 12 inches. The test wall bordering the Turbine Building (71) is concrete with an approximate th'ckness of 15 inches.
The east wall adjoining the Technical Support Center (2) is concrete with an approximate thickness of 12 inches.
The exterior wall is concrete with an approximate thickness of 12 inches with a steel and concrete knockout panel with metal latch and plaster cover on the outside. ~ The floor ato ceiling are concrete with a minimum thickness of 10 l
inches.
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Exemption Request 13 (Cont.),
j Access to the area is through two 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated doors from Fire Area RT1 and a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated door from the Turbine Building (71). Ventilation penetrations in the north wall and east wall are provided with 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire dampers.
Ventilation penetrations through the ceiling are not rated. Ventilation i
penetrations through the floor are provided with 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire dampers.
l i
The eletrical penetration seals in the north and east walls and the floor are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated. Mechanical penetration seals in the north wall are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated.
,i i
FIRE PROTECTION SYSTEMS:
1 l
l The area contains a wet pipe sprinkler system for suppression coverage in the f
Shif t Supervisor's office, the conference room, the kitchen and toilet, and corridor 344. Manual fire fighting equipment is available in the area and in I
adjacent areas RT1 and 27.
Ionization smoke detectors are located through the j
Computer Room, in approximately 407. of the Computer Room cabinets, and in all
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the Control Room cabinets.
j f
FIRE HAZARDS ANALYSIS:
i The combustible material in the Computer and Control Room consists of cabling, f
1 Class A materials, plastics, rubber, carpeting, and a small amount of solvent. The results in a fire loading of 38,210 BTU / square foot, which if totally consumed would correspond to a fire severity of approximately 28 I
minutes on the ASTM E-119 standard time-temperature curve.
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I f
Based on the nature and quantity of the fire loading in the area, the l
probability of a major fire occurring is remote.
If a fire were to occur, it l
would be detected in the incipient stages by either the Control Room personnel or the detection provided in the area. A fire detected in this stage would be adequately handled by the portable fire extinguishers available in the area.
3 The control Room personnel also serve on the fire brigade and, therefore are trained to extinguish fires.
l I
CONCLUSION:
}
l The fire area is constantly manned by operations personnel. Should a fire occur in the area, it would be detected by operations personnel or by the l
early warning ionisation detection provided in the hazard areas. Should the
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l Control Room become uninhabitable, shutdown outside the Control Room is l
accomplished by isolating all Train B systems and utilizing Train A systems to shutdown per the plant procedures for hot and cold shutdown in the event of a Control Room fire.
1 The District concludes that, although not in strict compliance with Appendix l
R.Section III.G.3, the protection provided by the existing configuration j
would not be significantly enhanced by the addition of a full area fixed l
suppression system.
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