ML13330A219
| ML13330A219 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/04/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Dietch R SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| TAC-48143, NUDOCS 8102270430 | |
| Download: ML13330A219 (20) | |
Text
DISTRIBUTION FEB 4 1981 Docket files
.rutchfield NRC POR Drthil L PDR SNowicki L PDRTWambach Docket No. 50-206 ORB#5 reading T
DHisenhut SHudson' RPurple HSmith TNovak NSIC RTedesco TERA Mr. R. Dietch GLainas ACRS (16)
Vice President, Nuclear Engineering J01shinski JHeltemes, AEOD and Operations OELD Southern California Edison Company OI&E(3) 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
The Commission has issued the enclosed Supplement No. 1 to the July 1979 Fire Protection Safety Evaluation Report (FPSER) for the San Onofr Nuclear Generating Station Unit No. 1. This supplement is in reference to your submittals dated January 23, and September 26, 1980, which provided details of installed Fire Protection Modifications and your responses to comments and recommendations dated April 16, and May 13, 1980 from our fire protection consultant, Brookhaven National Laboratory. This supple ment provides our safety evaluation of the following items:
3.1.1(1)
Control Room Fire Detection System 3.1.1(5)
Smoke Detectors in Lube 0i1 Area 3.1.2(a)
Fire Pump Test Features 3.1.2(b)
Fire Water Supply -
Isolation Valve 3.1.2(c)
Fire Water Supply - Units 2 and 3 Connection 3.1.5a)
Water Suppression System - 480 Volt Switchgear Room 3.1.5b)
Water Suppression System - North Turbine Building Area 3.1.5(c)
Water Suppression System - North Wall Structure 3.1.5(d)
Water-Suppression System - Wet Pipe Area Sprinkler 3.1.6 Foam Suppression System 3.1.7(a)
Gas Suppression System 4160 Volt Switchgear 3.1.7(b)
Gas Suppression System 480 Volt Switchgear 3.1.15(5)
Reactor Coolant Pump Oil Collection System 3.1.15(8)
Deluge System for Station Service Transformers 3.1.15(9)
Doorway of480 Volt Switchgear Room 3.2.2 Smoke Detection System Tests 3.2.3 Turbine Building Structure Some of the completion dates discussed in the Fire Protection Safety Evalua tion Report for San Onofre Unit No. 1 are noClonger valid as a result of the publication of a revised Section 10 CFR 50.48 and a new Appendix Rto 10 CFR 50 on November 19, 198.
The revised Table 3.1 included in Supple ment No.
a supersedes Table 3.1 of the July 19, 1979 FPSER. Thisrevised.
,OIL 02 27 0 q2 Wate SupesoAytm-We ieAe pike
Mr. R. D1etch Table reflects the requirements that your items 3.1.15.5 (Oil Collection System for Reactor Coolant Pump) and 3.1.17 (Emergency Lighting) be revised to comply with the new Appendix R. Table 3.1 also provides the status of our review of the fire protection program for San Onofre Unit No. 1 and supersedes Section 3.0 of your FPSER concerning accept ability of design.
The enclosed Table 3.2 supersedes Table 3.2 of the July 19, 1979 FPSER.
This new table reflects the acceptance of Items 3.2.2 and 3.2.3 and the issuance of a revised Section 10 CFR 50.48 and a new Appendix R to 10 CFR 50.
You will note that although item 3.1.1l.e (Fire Stops in Cable Trays) was inadvertently indicated as complete in the FPSER, this item will be reviewed on a schedule consistent with 10 CFR 50.48 and is included in Table 3.2 of the enclosed Supplement.
Sincerely, Original Signed by Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing
Enclosure:
Supplement No. 1 to the Fire Protection SER cc w/enclosure:
See next page OFFICE ORB#5' 0t
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.UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 FEB 4 1981 Docket No. 50-206 Mr. R. Dietch Vice President, Nuclear Engineering and Operations.
Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
The Commission has issued the enclosed Supplement No. 1 to the July 19, 1979 Fire Protection Safety Evaluation Report (FPSER) for the San Onofre Nuclear Generating Station Unit No. 1. This supplement is in reference.
to your submittals dated January 23, and September 26, 1980, which provided details of installed Fire Protection Modifications and your responses to comments and recommendations dated April 16, and May 13, 1980 from our fire protection consultant, Brookhaven National Laboratory. This supple ment provides our safety evaluation of the following items:
3.1.1(1)
Control Room Fire Detection System 3.1.1(5)
Smoke Detectors in Lube Oil Area 3.1.2(a).
Fire Pump Test Features 3.1.2(b)
Fire Water Supply -
Isolation Valve 3.1.2(c)
Fire Water Supply -
Units 2 and 3 Connection 3.1.5(a)
Water Suppression System -
480 Volt Switchgear Room 3.1.5(b)
Water Suppression System -
North Turbine Building Area 3.1.5(c)
Water Suppression System -
North Wall Structure 3.1.5(d)
Water Suppression System -
Wet Pipe Area Sprinkler 3.1.6 Foam SuppressionSystem 3.1.7(a)
Gas Suppression System -
4160 Volt Switchgear 3.1.7(b)
Gas Suppression System -
480 Volt Switchgear 3.1.15(5)
Reactor Coolant Pump Oil Collection System 3.1.15(8)
Deluge System for Station Service Transformers 3.1.15(9)
Doorway of 480 Volt Switchgear Room 3.2.2 Smoke Detection System Tests 3.2.3 Turbine Building Structure Some of the completion dates discussed in the Fire Protection Safety Evalua tion Report for San Onofre Unit No. 1 are no longer valid as a result of the publication of a revised Section 10 CFR 50.48 and a new Appendix R to 10 CFR 50 on November 19, 1980. The revised Table 3.1 included in Supple ment No. 1 supersedes Table 3.1 of the July 19, 1979 FPSER. This revised
Mr. FEB 4 1981 Table reflects the requirements that your items 3.1.15.5 (Oil Collection System for Reactor Coolant Pump) and 3.1.17 (Emergency Lighting) be revised to comply with the new Appendix R. Table 3.1 also provides the status of our review of the fire protection program for San Onofre Unit No. 1 and supersedes Section 3.0 of your FPSER concerning accept ability of design.
The enclosed Table 3.2 supersedes Table.3.2 of the July 19, 1979 FPSER.
This new table reflects the acceptance of Items 3.2.2 and 3.2.3 and the issuance of a revised Section 10 CFR 50.48 and a new Appendix R to 10 CFR 50.
You will note that although item 3.1.1l.e (Fire Stops in Cable Trays) was inadvertently indicated as complete in the FPSER, this item will be reviewed on a schedule consistent with 10 CFR 50.48 and is included in Table 3.2 of the enclosed Supplement.
Sincerely, Dennis M. Crutchfield, C ef Operating Reactors Branch #5 Division of Licensing
Enclosure:
Supplement No. 1 to the Fire Protection SER cc w/enclosure:
See next page
Mr. R. Dietch FEE 4 1981
-3 cc w/enclosure:
Charles R. Kocher, Assistant Director, Technical Assessment General Counsel Division Southern California Edison Company Office of Radiation Programs Post Office Box 800 (AW-459)
Rosemead, California 91770 U. S. Environmental Protection Agency David R. Pigott Crystal Mall #2 SSamuel B. Casey Arlington, Virginia 20460 Chickering & Gregory Three Embarcadero Center U. S. Environmental Protection Twenty-Third Floor Agency San Francisco, California 94111 Region IX Office ATTN:
EIS COORDINATOR Jack E. Thomas 215 Freemont Street Harry B. Stoehr San Francisco, California 94111 San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 Resident Inspector c/o U. S. NRC P. 0. Box AA Oceanside, California 92054 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors
'County of San Diego San Diego, California 92101 California Department of Health ATTN:
Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814
SUPPLEMENT NO. 1 TO THE JULY 19, 1979 FIRE PROTECTION SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION U. S. NUCLEAR REGULATORY COMMISSION PROVISIONAL OPERATING LICENSE NO. DPR-13 SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 1 DOCKET NO, 50-206 Date: FEB 4 981
1.0 Introduction and Background On July 19, 1979, the Commission issued Amendment No. 44 to Provisional Operating License No. DPR-13 for the San Onofre Nuclear Generating Station, Unit No. 1. The amendment added license conditions relating to the comple tion of facility modifications and implementation of administrative controls for fire protection. Certain items listed in Section 3.0 of the supporting Fire Protection Safety Evaluation Report (FPSER) were noted as requiring additional information to assure that the design is acceptable prior to actual implementation.
Southern California Edison Company (the licensee) supplied this information by letters dated October 23, 1979, and January 23, 1980.
In addition, by letter dated September 26, 1980, the licensee responded to the additional comments and recommendations of our fire protection consultants as contained in the letters to the NRC dated April 16, and May 13, 1980.
This supplement provides the staff's evaluation of the modifications
. discussed in the above referenced letters.
Each modification is iden tified by title and section number, consistent with Section 3.0 of the July 19, 1979 FPSER.
On November 19, 1980 (45 FR 76602) the Commission published a revised Section 10 CFR 50.48 and a new Appendix R to 10 CFR 50 regarding fire protection features of nuclear power plants. The revised Section 50.48 and Appendix R require that Fire Protection of Safe Shutdown Capability, Emergency Lighting, and Oil Collection Systems for Reactor Coolant Pumps be backfit according to Appendix R-and open items of previous staff fire protection reviews be completed. Section 50.48 also addresses completion requirements.regarding modifications that have previously been approved by the staff but have not been implemented, and to fire protection features that have not been previously approved as satisfying the provisions of Appendix A to Branch Technical Position BTP PCSB9.5-1.
2.0 Evaluation
- In the FPSER dated July 19, 1979, many modifications were approved for implementation in coniunction with the Systematic Evaluation Program (SEP).
The publication of the revised Section 50.48 and Apoendix R reouires acceler ation of thp schedules given in Table 3.1 and Table 3.2 of the FPSER. We have rpviced Tables 3.1 and 3.2 to be consistent with the new Section 50.48, Appendix R, and the status of the actual implementation of modifications at the facility. The enclosed tables which now supersede Table 3.1 and Table 3.2 of the July 19, 1979 FPSER also incorporate the results of the evalua tion by the staff of the following modifications.
-2 3.1.1(1)
Fire.Detection System -
Control Room In the FPSER, it was our concern that a fire in the vital bus cabinet in the control room could go undetected.
By letter dated October 29, 1979, the licensee proposed to install a UL or FM listed ionization type smoke detector in each vital bus cabinet.
The detectors will be electrically supervised and will be part of the existing MCR area detection system.
The licensee's.proposal to provide a UL or FM listed smoke detector in each vital bus cabinet of the control room meets Section F(2) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.1(5)
Fire Detection Systems Our concern that the fire detection system in the turbine lube oil reservoir area of the turbine building may not be adequate to detect a fire in this area is documented in the FPSER.
By letter dated September 26, 1980, the licensee provided additional information regarding their fire detection system protecting the lube oil reservoir and conditioner area. The lube oil reservoir and condi tioner are enclosed by a four foot high wall.
The licensee has installed infra-red flame detectors and line-type heat detectors in this diked area.
Ine installation of the six infra-red flame detectors provides the capability for line-of-sight surveillance over the entire area enclosed by the dike. Also, the installation meets all of the recommendations of NFPA 72E, Chapter 5, - "Flame Sensing Fire Detectors."
The fire detection system which the licensee has installed would be adequate to detect either a fire originating in the cable trays or an exposure fire in the lube oil reservoir and conditioner area. In addition to the flame detectors and line type heat detectors, the
. existing system of ionization smoke detectors located in this area was left intact. This provides additional detection capability for this area.
Based on our review, we conclude that the fire detection system for the turbine lube oil reservoir and conditioner area, which is installed in accordance with NFPA 72E, meets Section C.5(a)(3) of BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.2(a) Fire Pump Test Features As stated in the FPSER, we were concerned that the test method conducted to verify the fire pump curves may not be adequate since they do not meet".the recommendations of NFPA 20.
By letter dated January 23, 1980, the licensee provided information to show the test method used at their plant complies with NFPA 20. We informed the licensee that the use of a 2-inch valve on an 8-inch pump header to relieve the pressure to the pressure actuated control switch as
30 a means of testing the control setpoints of the fire pumps does not allow for sufficient accuracy in.determining the pressure setpoints and does not meet the recommendations of NFPA'20. Additionally, we informed the licensee that the use of the 480 volt switchgear as a pump controller is not in compliance with NFPA 20, since it is not a UL listed controller.
By letter dated September 26, 1980, the licensee proposed to install a 1/2-inch line with 1/2-inch check valves which meets the recommendations of Appendix A to NFPA 20. The.licensee also verified that the switchgear breaker used as a controller meets the requirements for UL listed controllers.
Based on the licensee's proposed modifications, we conclude that the test features for the fire pumps will meet the recommendations of NFPA 20 and, therefore, are acceptable.
3.1.2(b) Fire Water Supply We state in our FPSER that a single break in the above ground cross connection of the yard loop-which is routed through the turbine building could result.in the loss of both manual and automatic fire suppression for areas of the turbine building.
By letter dated September 26, 1980, the licensee provided additional information regarding their design of the manual and automatic fire suppression capability within the lube oil area of the turbine building.
In our evaluation of the additional information, we concluded that the single isolation valve in the turbine building cross connection did not isolate the automatic suppression system and standpipe stations in all areas of the turbine building (i.e., the hydrogen seal oil unit area).
A subsequent review of.the fire water piping drawings for the turbine building and discussions with the licensee, indicate that although a break in the cross connection will cause the loss of the automatic foam system, which protects the hydrogen seal oil unit area, and hose reel
- 5, which provides manual fire suppression capability for this area, an alternate hose reel would still be functional.
This alternate hose reel (HR#6) is capable of providing manual fire suppression capability for.the hydrogen seal oil unit area.
Therefore, a single break in the above ground cross connection of the yard loop which is routed through the turbine buil'ding would not result in the loss of both manual and automatic fire suppression capability in any area of the turbine building.
Based on our review, we conclude that a single break in the fire water piping would not result in the loss of both automatic and manual fire suppression capability for the turbine.building which meets Section E.3(a) of Appendix A to BTP APCSB 9.5-1, and, therefore, is acceptable.
-4 3.1.2(c)
Fire Water Supply As stated in the FPSER, we are concerned that a break in the 8-inch supply to the Unit 1 fire pumps would place both pumps out of service.
We recommended that a check valve with a parallel bypass valve be provided in the Units 2 and 3 connection to the Unit 1 fire water loop to provide an alternate fire water source for Unit 1.
By letter dated October 23, 1979, the licensee provided information regarding the modification to intertie the Unit 1 and Units 2 and 3 fire water systems.
A check valve will be installed to allow flow from the Units 2 and 3 fire water system to the Unit 1 fire water system. During normal opera tion, the higher pressure in the Unit 1 system will keep this valve closed. In case of loss of system pressure and loss of the Unit 1 fire pumps, the check valve will open allowing the flow into the Unit 1 system. A normally closed block valve will also be provided as a bypass to allow the Unit 1 fire pumps to be used as backups to the Units 2 and 3 fire system. All valves installed will be UL listed or FM approved. All piping and valves will be installed in accordance with the recommendations of NFPA.
The licensee's proposed modifcation to intertie the Unit 1 and Units 2 and 3 fire water systems will assure an adequate backup fire water source for Unit 1. Further, the valves will permit maintaining the independence of the individual loop around each unit which meets our guidelines.
Based on our-review, we find that the licensee's proposed interconnection for the Unit 1 and Units 2 and 3 fire water systems meets Section.E.2(b) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.5(a) Water Suppression Systems.
3.1.5(c)
In the FPSER,. it was our concern that an unmitigated fire involving the
- turbine lube oil reservoir could adversely affect the north wall and structural steel, and the east wall of the 480 volt switchgear room.
We recommended that the east wall of the 480 volt switchgear room and the north wall and structural steel members in the turbine lube oil reservoir area be protected by a directed water spray system.
By letters dated October 23, 1979, January 23, 1980, and September 26, 1980, the licensee provided information regarding fire protection for the turbine lube oil reservoir area.
The licensee will provide a fusible link wet pipe sprinkler system to protect the east wall of the 480 volt switchgear room, and the north wall and structural steel members. The directed water spray system will provide a water screen to cool these walls and steel members in the
5 event of an unmitigated fire. The system will be designed, installed, fabricated, and tested to comply with NFPA 13 and 15.
All equipment will be UL or FM listed. The design water density for the spray will be 0.15 gpm/sq. ft. which is adequate for exposure protection.
Based on our review, we conclude that the proposed wall sprinkler system, which meets NFPA 13 and 15, meets Section E.3(c) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.5(b) North Turbine Building Area, Cable Water Spray System With respect to our concern that the fire protection provided for the cable trays in the north turbine building area was not adequate, we recommended that a sectionalized directed water spray system be provided, in addition to already existing systems. We also recommended that actuation of the system be provided by use of line-type temperature detectors placed in the cable trays.
In the letter dated January 23, 1980, the licensee provided the drawings of their proposed cable tray water spray deluge system. Additionally, the licensee stated that a line type heat detection system is located in the cable trays and used to actuate the deluge system. We informed the licensee that the system be designed to provide a water spray density of at least 0.15 gpm/ft.2.
We also recommended that the licensee provide three water spray deluge systems.
By letter dated September 26, 1980, the licensee -verified that the design density of the water spray systems is 0.15 gpm/ft 2. Additionally, the Iciensee verified that the cable trays in the area are divided into three sections with a separate water spray and deluge valve, with manual actuation capability for each section..
The licensee's water spray design density is in accordance with the recommendations of NFPA 15 and, therefore, acceptable. The licensee has
, sectionalized the cable tray water spray deluge systems such that each section can operate independently of the other which meets our recommen dations and Section E.3(a) of Appendix A to BTP APCSB 9.5-1and, therefore, is acceptable.
3.1.5(d) Water Suppression System In this Section of the FPSER, we were concerned that the licensee had not provided adequate fire protection for the large concentration of combus tibles in the north turbine area (Fire Area 9A).
By letter dated January 23, 1980, the licensee indicated that an automatic sprinkler system designed to provide a minimum density of 0.3 gpm/sq. ft.
for fire area 9A would be provided. We informed the licensee that the proposed area sprinkler system was not acceptable since a single break in the fire header could simultaneously impair operation of the wet pipe
area sprinkler system and the cable tray water spray deluge system. We recommended that the licensee provide sufficient valves in the fire water system looped header to assure that a single break will not impair operation of the wet pipe area sprinkler system and any other automatic suppression systems for area 9A.simultaneously.
By letter dated September 26, 1980, the licensee committed to provide a separate feed from the yard loop with adequate valving to prevent the simultaneous loss of both the cable tray water spray deluge system and the fusible link water sprinkler system due to a single pipe break.
The licensee's proposed modification meets Section E.3(a) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.6 Foam Suppression System We stated our concern that the manual deluge system did not provide adequate fire protection for the lube oil reservoir and conditioner, and therefore, recommended that the deluge system for the lube oil reservoir and conditioner be modified to provide an automatic foam suppression system.
By letter dated January 16, 1980, the licensee proposed a foam system for this area.
The licensee stated that the design density for.the lube oil area foam system will be 0.16 gpm/sq. ft.
We found -the system was not adequate. We recommended that the foam system supply connection to the turbine building fire protection header be isolated from the other lube oil reservoir area protection systems by providing approved Outside Stem and Yoke valves inthe header.
We also recommended that the system comply with the provisions of NFPA 16.
By letter dated September 26, 1980, the licensee proposed to modify the foam system connection to the yard loop so that it will be isolated from the other systems in the area.
Further, the licensee verified that the system complies with the recommendations of NFPA 16.
Based on the licensee's commitment to isolate the foam suppression system from other systems in the area and verification that the foam system meets NFPA 16, we conclude the foam suppression system is acceptable.
3.1.7(a) Gas Suppression System Tbtal Flooding Halon 1301 for 4160 Volt Switchgear Room As documented in our FPSER, we recommended that the licensee provide an automatic total flooding Halon 1301 gas suppression system and that the system be designed to permit a second application of the suppression agent, as a result of our concern that the fire protection for the 4160 volt switchgear room may not be adequate.
7 By letter dated January 23, 1980, the licensee proposed to provide a Halon 1301 system for the 4160 V switchgear room. The system will be designed to provide a 6% concentration for a soak time of 10 minutes, and that the discharge time would be 10 seconds. We found that the design criteria were not adequate. We recommended that the licensee revise the design criteria of the proposed system to provide for a 7%
concentration for a 20 minute soak time.
By letter dated September 26, 1980, the licensee provided the results of a Halon system discharge test, showing higher concentration and soak time than the system was designed for. During the 15 minutes time period the concentration within the room ranged from a high of 10% initially to a low of 7.2% after 15 minutes.
Based on the licensee's test results, we conclude the Halon 1301 system is capable of providing the recommended concentration for the required soak time.
We conclude that the system meets Section E.4 of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.7(b)
Gas Suppression System - Total Flooding Halon 1301 for 480 Volt.Switchgear Room We recommended that the licensee provide an automatic total flooding Halon 1301 gas suppression system, in conjunction with our concern that the fire protection for the 480 vol:t switchgear room may not be adequate.
By letter dated January 23, 1980, the licensee proposed to provide a total flooding Halon 1301 system for this area. The system would be designed to provide a 6% concentration for a soak time of 10 minutes.
We found that the desi.gn criteria were not adequate.
We recommended that the licensee revise the design criteria of the proposed system to provtde a 7% concentration for a 20 minute soak time.
By letter dated September.26, 1980, the licensee indicated that the Halon system for the 480 volt switchgear room will provide a 7% concentration for a 20 minute soak time.
Additionally, the licensee committed to conduct a performance test of this system.
Based on the licensee's commitment to provide a Halon system for the 480 volt switchgear room capable of providing a 7% concentration for 20 minutes, we conclude that the system meets Section E(4) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3.1.15(5)
Control of Combustibles We recommended that an oil collection system be provided for the reactor coolant pumps, in connection with our concern that an unmitigated fire involving the lubricating oil in the reactor coolant pumps could result in the loss of redundant systems required for safe shutdown.
- 8 By letter dated October 23, 1979, the licensee provided information regarding the proposed reactor coolant pump lube oil collection system.
Drip pans and spray shields will be installed for each of the three reactor coolant pumps. -The shield consists of a fabricated stainless steel housing for the-lube oil pump on each RCP. Also installed will be drain pans beneath.the lube oil pump, the upper and lower liquid level controls, the lube oil cooler, and the lube oil cooler/RCP flanged connections. The licensee has not provided reasonable assurance that the system will withstand the safe shutdown earthquake (See Reg. Guide 1.29 "Seismic Design Classification" Paragraph C.2). Additionally, the licensee-has not verified that the leakage will be collected and drained to a vented closed container that can hold the entire lube oil system inventory.
Based on our review, we conclude that the proposed oil collection system does not meet Section 111(0) of Appendix R to 10 CFR 50 and, therefore, is not acceptable. The licensee should provide an oil collection system which meets Section 111(0) of Appendix R to 10 CFR 50.
3.1.15(8) Deluge System for Station Service Transformers In regard to our concern that the fire protection provided for the station service transformer was not adequate, we recommended that the licensee either replace the oil with a silicone base oil or provide an automatic deluge system to protect the transformers.
By letter dated January 23, 1980, the licensee proposed to provide an automatic deluge system to protect the station service transformers. The:
system will comply with NFPA 15.
Since the licensee did not specify the design criteria, we recommended that sufficient nozzles be provided to deliver a 0.3 gpm/sq. ft. water spray density over all surfaces of the transformers, including 0.15 gpm/sq. ft. on all non-absorbing ground surface area of exposure.
By letter dated September 26, 1980, the licensee proposed to provide additional discharge nozzles to assure compliance with the recommendations of NFPA 15.
The specific design parameters are 0.25 gpm/sq. ft. over all surfaces of the transformers and 0.15 gpm/sq. ft. on expected non absorbing ground surface. These design parameters meet Section 4-4.3.4(a) of NFPA 15.
Based on the licensee's commitments to provide an automatic deluge system which meets NFPA 15, we conclude that the protection for the transformers meets Section E.3(c) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3 1.15(9) Doorway of 480-Volt Switchgear Room With respect to our concern that the equipment inside the 480-volt switch gear room could be affected by a fire involving the transformer oil spreading through the doorway facing these transformers, we recommended that the doorway of the 480-volt switchgear room facing the service station transformers be filled in to provide a fire barrier rating of at least three hours.
By letter dated September 26, 1980, the licensee proposed to provide a three-hour fire rated door in lieu of filling in the doorway facing the service station transformers. In addition, the licensee will provide curbing around the transformers to contain any oil in the event of a transformer oil leak.
The three-hour fire rated door should prevent a fire imvolving the station service transformers from propagating to the 480-volt switch gear room through the doorway. In addition, the curbing around the transformers will prevent oil from spreading into the 480-volt switchgear room via the doorway.
Based on our review, we conclude that the licensee's proposed fire protec tion modification meets Section D.1.(h) of Appendix A to BTP APCSB 9.5-1 and, therefore, is acceptable.
3..2.2 Smoke Detection Systems Tests We stated our concern that the smoke detectors might not respond to the products of 'combustion for the combustibles in the areas where smoke detectors are installed. We were also concerned that ventilation air flow patterns in the area might reduce or prevent detector response and we recommended that the licensee perform an in-situ smoke detector test.
By letter dated January 23, 1980, the licensee committed to conduct bench testing to verify that the smoke detection installed in an area will provide prompt.response and have adequate sensitivity to the products of combustion for the types of combustibles in the areas where smoke detectors are installed. In addition, the smoke detector systems are designed and installed by qualified personnel and meet the appropriate NFPA codes.
The required methodology for the in-situ smoke detector test is beyond the current state-of-the-art and, therefore, an in-situ test cannot be performed at this time.
We find that with acceptable bench testing of smoke detectors, and consi dering that the smoke detection systems meets appropriate NFPA codes and are designed by experienced personnel, the smoke detectors are acceptable.
10 3.2.3 Turbine Building Structure In the FPSER, we stated our concern that an unmitigated fire involving the hydrogen seal oil system could adversely affect the structural steel in the adjacent area to the hydrogen seal unit of the turbine building.
By letters dated December 26, 1979,and September 26, 1980, the licensee provided the results of their calculations, their assumptions used in the calculations, and their basis for these assumptions.
The calculations indicate that the peak temperatures expected to occur at the steel support columns of the south turbine deck extension due to an 8-hour unmitigated fire involving 12,300 gallons of seal oil would be a maximum of 604 0F.
The licensee's c.alculations, which are based on conservative assumptions, indicate that the peak temperature in the steel columns would be signifi cantly below the critical temperature of steel (which is approximately 11000F).
The licensee has proposed to protect the hydrogen seal oil unit with an automatic foam suppression system with manual fire suppression backup and curbing to contain an oil leak. The ceiling above the hydrogen seal oil unit is higher than that above the columns and opens to the outdoors to 'the east (the columns are south of the area). The walls in the area south of the hydrogen seal unit are penetrated by large louvered openings. In the event of a fire involving the hydrogen seal oil unit, outside air would be drawn through these openings past the columns and toward the fire. The air would then be heated by the fire, rise and be ventilated to the outdoors. Therefore, due to this chimney effect the air heated by the fire would not adversely affect the columns.
Because the proposed fire protection modifications for the hydrogen seal oil unit area should preclude an unmitigated oil fire, the area is open to the outdoors, and the calculations indicate that the theoretical maximum steel temperatures are below the critical temperature of steel, we conclude that a fire involving the hydrogen seal oil unit would not affect the structural integrity of the steel columns. Therefore, we find the licensee's proposed fire protection for this area acceptable.
3.0 Summary and Conclusions Except for the open items identified in our letter dated November 24, 1980, which transmitted the Fire Protection Rule (45 FR 76602, November 19, 1980), this concludes our review of plant modifications to improve the fire protection capability at San Onofre Nuclear Generating Station Unit 1 in accordance with Appendix A to BTP 9.5-1.
The enclosed Tables 3.1 and 3.2 reflect the approval of the design details of the proposed modifications and provide the required implementation schedule. Since some of the modifications deferred to the SEP for imple mentation should be already completed according to the revised Section 50.48,
2
- 11 the-licensee will be requi:red to request an extension prior to February 17, 1981.
The open items i.dentifited iln our November 24, 1980 letter will be resolved by the licensee in conformance with the requirements of Appendix R on the schedule specifted in 10 CFR 50.48(c).
Attachments:
Tables 3.1 and 3.2
TABLE 3.1 SER No.
Item Review Status implementation Schedule 3.1.1 Fire Detection (1) (5)
Complete Done (2)(3)(4)(6)(8)(9)(10)(11) 50.48*
50.48(c) 3.1.2 Fire Water Supply (a)
Complete.
50.48(d)
(b)(c)
Complete Done 3.1.3 Yard Hydrants Complete Done 3.1.4 Hose Stations Complete Done 3.1.5 Water Suppression Systems Complete 50.48(d) 3.1.6.
Foam Suppression Systems Complete 50.48(d) 3.1.7 Gas Suppression Systems (a)
Complete Done (b)
Complete 50.48(d) 3.1.8 Portable Extinguishers Complete Done 3.1.9 Fire Doors Complete Done 3.1-.10 Supervision of Fire Doors Complete Done 3.1.11 Fire Barriers (a) (c)
Complete Done (b)(d)
Complete 50.48(d)
(e) 50.48 50.48(c) 3.1.12 Fire Dampers (a)
Complete Done (b)(c)
Complete 50.48(d) 3.1.13 Fire Barrier Penetrations (1)(2)(5)
Complete Done (3)(4)
Complete 50.48(d) 3.1.14 Water Damage Protection Complete 50.48(d) 3.1.15 Control of Combustibles (1)(2)(3)(4)(6)(7)(8)(9)(10)
Complete Done (5)
Appendix R**
50.48(c) 3.1.16 Isolation Devices Complete Done 3.1.17 Emergency Lighting Appendix R1 50.48(c)
(Issued by Supplement No. 1)
-2 Table 3.1 (continued)
- In accordance with 10 CFR 50.48
- To be implemented in accordance with Appendix R requirements and 50.48 schedule
.1
.Although previously approved and completed to be modified per Appendix R requirements and 50.48 schedule (Issued by Supplement No. 1)
Table 3.2 0
Item Review Schedule*
- 1. Alternate Shutdown Capability................... 10 CFR 50.48
- 2. Smoke Detection System Tests.................. Complete
- 3. Turbine Building Structure.................... Complete
- 4. Cable Spreading Area......................... 10 CFR 50.48
- 5. Containment................................. 10 CFR 50.48
- The implementation schedule for the items in this Table are governed by 10 CFR 50.48 (Issued by Supplement No. 1)