ML20203F860

Evaluation of Fire Protection Exemption Requests from 10CFR50.48 & App R to 10CFR50,San Onofre Nuclear Generating Station Unit 1, Technical Evaluation Rept

ML20203F860
Person / Time
Site:	San Onofre
Issue date:	04/23/1986
From:	Carfagno S CALSPAN CORP.
To:	NRC
Shared Package
ML13316A931	List: ML20203F860
References
CON-NRC-03-81-130, CON-NRC-3-81-130 TER-C5506-622, NUDOCS 8604280092
Download: ML20203F860 (22)

Text

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ENCLOSURE TECHNICAL EVALUATION REPORT

NRC DOCKET NO. 50-206 FRC PROJECT CS506 NRC LICENSE NO. DPR-13 FRC ASSIGNMENT 36 NRC CONTRACT NO. NRC4341-130 FRC TASK 622 h

I EVALUATION OF FIRE PROTECTION EXEMPTION REQUESTS FROM 10CFR50.48 AND APPENDIX R TO 10CFR50 SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION UNIT 1 TER-C5506-622 I

Preparedfcr Nuclear Regulatory Commission FRCGroup Leader: N. Ahmed Washington, D.C. 20555 NRC Lead Engineor: J. Stang April 23, 1986 I This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their N employees, makes any warranty, expressed or implied, or assumes any legal liability or U responsibility for any third party's use, or the results of such use, of any information, appa-retus, product or process disclosed in this report, or represents that its use by such third

, party would not infringe privately owned rights.

I Prepared by: Reviewed b : Approved by:

,a, - C M- M PrincipalfuTor / /

Mpar'tm'ent[2 rep 3-80 Date: 4/23fd Date: / 22df Date: 6-7 P~ l / .

y ( LQ FRANKLIN RESEARCH CENTER g

t y DivtS.

s . . .IONmOF ARVIN/CALSPAN

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TER-C5506-622 CONTENTS Section Title Page 1 INTRODUCTION . . . . . . . . . . 1 I 1.1 Purpose of Review . . . . . . . . 1 l 1.2 Generic Background . . . . . . . . 1 1.3 Plant-Specific Background . . . . . . 3 1.4 Review Criteria . . . . . . . . . 4 2 EVALUATION . . . . . . . . . . . 5 2.1 General ".

8 . . . . . . . . . 5 2.2 Reactor Auxiliary Building Lower Level (Fire Area 1-AB-(3)-2A]

East Penetration Area (Fire Area 1-YD-20-4A]

West Penetration Area (Fire Area 1-YD-20-4B]

Yard Area (Fire Area 1-YD-14-4D]

Circulating Water Pump Well (Fire Area 1-YD-(7)-4-E]

Turbine Building Ground Floor (Fire Area 1-TB-8-9A]

Turbine Deck (Fire Area 1-TB-35-9B]

Control Room Complex (Fire Area 1-PB-56-33) . . 5 2.3 Containment (Fire Area 1-CO-(10)-1] . . . . 12 l 3 CONCLUSIONS . . . . . . . . . . . 16 4 REFERENCES . . . . . . . . . . . 18 1

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TER-C3506-622 FOREWORD This Technical Evaluation Report was prepared by Franklin

, Research Center (FRC) under a contract with the U.S. Nuclear i Regulatory Commission (Office of Nuclear Reactor Regulation, 8

Division of Operating Reactors) for technical assistance in support of NRC operating reactor licensing actions. The technical evaluation was conducted in accordance with criteria established by the NRC.

Mr. Gregory Harrison, a consultant to FRC, contributed to the technical preparation of this report.

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1. INTRODUCTION 1.1 PURPOSE OF REVIEW l

This technical evaluation report documents an independent

[' review of exemptions or deviations from the fire protection requirements of 10CFR50.48 or Appendix R to 10CFR50 requested for Southern California Edison Company's (SCECo) San Onofra Nuclear Generating Station Unit 1. This evaluation was performed with the following objectives:

P, o To assess if each exemption request demonstrates an L equivalent level of overall protection of plant safe l shutdown capability following a disabling fire event o To determine the bases for acceptance or denial of each exemption request I o To recommend the minimum level of fire protection the applicant or licensee should provide to achieve an equivalent level of fire protection in case a request is danied.

1.2 GENERIC BACKGROUND Following a major fire at the Browns Ferry Nuclear Station in March 1975, the NRC established a Special Review Group which initiated an evaluation of the need for improving the fire I protection programs at all nuclear power plants. The group found serious design inadequacies regarding fire protection at Browns Ferry, and its report, " Recommendation Related to Browns Ferry Fire" (NUREG-0050, February 1976), contained over 50 recom-I mandations regarding improvements in fire prevention and control in existing facilities. The report also called for the development of specific guidance for implementing fire protection regulations, and for a comparison of that guidance with the fire protection program at each operating plant.

NRC developed technical guidance from the technical recom-mandations in the Special Group's report, and issued those guidelines as Branch Technical Position (BTP) APCSB 9.5-1 (1).

This guidance did not apply to plants operating at that time.

l Guid2nce to operating plants was provided later in Appendix A to BTP APCSB 9.5-1 (2), which, to the extent practicable, relies on BTP APCSB 9.5-1. The guidance in these documents was also published as Regulatory Guide 1.120 (3).

By early 1980, most operating plants had implemented mostlof the guidelines in Appendix A. However, the fire protection program has had some significant problems with implementation. To establish a definitive resolution of these problems in a manner consistent with the general guidelines in Appendix A to the BTP and to assure timely compliance by licensees, the Commission issued a proposed fire protection rule and its Appendix R, which was

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described as setting out minimum fire protection requirements for the unresolved issues. The fire protection features addressed included protection of safe shutdown capability, emergency lighting, fire barriers, associated circuits, reactor coolant pump lubrication system, and alternate shutdown systems.

I On February 17, 1981, the final rule 10CFR50.48 (4] and Appendix R to 10CFR50 (5] became effective, replacing the proposed

! rule. Only three of the 15 items in Appendix R were of such safety i significance that they should apply to all plants, including those for which alternative fire protection actions had been approved F previously by the staff. These items are protection of safe L shutdown capability (including alternate shutdown systems),

emergency lighting, and the reactor coolant pump lubrication system. Accordingly, the final rule required all reactors licensed to operate before January 1, 1979, to comply with these three items even if the NRC had previously approved alternative fire protection features in these areas. However, the final rule is more flexible I than the proposed rule because Item III.G now provides three alternative fire protection features which do not require analysis to demonstrate the protection of redundant safe shutdown equipment, and reduces the acceptable distance in the physical separation I alternative from 50 feet to 20 feet. In addition, the rule now provides an exemption procedure which can be initiated by a licensee's assertion that any required fire protection feature will not enhance fire protection safety in the facility or that such I modifications may be detrimental to overall safety.

I In summary,Section III.G is related to fire protection features for ensuring that systems and associated circuits used to achieve and maintain safe shutdown are free of damage. Either fire protection configurations must meet the specific requirements of I Section III.G or an alternative fire protection configuration must be justified by a fire hazard analysis. Generally, the staff will accept an alternative fire protection configuration if:

l' o The alternative ensures that one train of equipment

- necessary to achieve hot shutdown from either the control g room or emergency control stations is free of fire damage.

l y o The alternative ensures that fire damage to at least one train of equipment necessary to achieve cold shutdown is l limited so that it can be repaired within a reasonable time (minor repairs using components stored on the site).

o Fire-retardant coatings are not used as fire barriers.

o Modifications required to meet Section III.G would not

, enhance fire protection safety levels above those provided by either existing or proposed alternatives,..

o Modifications required to meet Section III.G would be detrimental to overall facility safety.

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Guidance to the industry and the NRC positions on certain requirements of Appendix R is covered by various documents, one of i them being the Generic Letter 83-33 (6) which has recently been slated to be superseded by yet another draft Generic Letter 85-01 (7). "The interpretations of Appendix R" and "the responses to industry questions," two sections of Reference 7, are written to facilitate industry implementation of Appendix R and represent NRC position on all issues covered.

Following the promulgation of the final rule, licensees and applicants have requested exemptions and deviations from Appendix R g to 10CFR50. The exemptions and deviations are in the form of a h fire hazard analysis. The NRC is to review exemption requests and associated analysis to ensure each alternative to meeting the requirements of the rule provides an equivalent level of overall I protection of plant safe shutdown capability. Franklin Research Center (FRC) was to provide technical assistance to the NRC within the context of the following scope of work (8):

Subtask 1: Review each exemption request for information deficiencies. Provide Request for Information (RFI) to resolve such deficiencies.

I Subtask 2: Review and evaluate each exemption or deviation request submitted by the licensees or the I applicants and all additional information provided for conformance with acceptance criteria. Prepare final Technical Evaluation Report (TER) with I recommendations, and their basis in support of granting or denying the exemption / deviation request.

1.3 PLANT-SPECIFIC BACKGROUND By letter dated October 4, 1985, the Licensee requested exemptions from Section III.G of Appendix R.

I Subsequently, on November 14 and 15, 1985, a meeting was held between the NRC and SCEco in Bethesda, Maryland, for the purpose of reviewing the Appendix R exemption requests. By letter dated December 10, 1985, the NRC requested additional information from SCECo. In response to this request and to issues raised during the November meeting, the Licensee submitted, by letter dated December 31, 1985, revised I exemptions and responses to NRC questions (9).

The Request for Information (RFI) required in satisfaction of Subtask 1 was transmitted to the NRC on December 2, 1985 (10). A site visit was conducted on January 13, 1986, to review the areas where exemptions were requested and to collect additional information requested in the RFI.

A draft TER reflecting the Licensee's submittal (s) was issued to NRC on April 3, 1986. NRC provided comments on the draft TER.

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The contents of this final TER reflect the information contained in the Licensee's submittal (9) as revised and supplemented by their subsequent transmittals through February 18, 1986. It also reflects resolution / incorporation of NRC comments received to date.

3 1.4 REVIEW CRITERIA The criteria used in reviewing the Licensee-submitted i exemption requests are based on the following documents:

Fire Protection Program for Operating Nuclear Power

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Plants, 10CFR50.48

2. Appendix R to.10CFR50

3. Standard Review Plan, NUREG-0800, Branch Technical Position (BTP), APCSB 9.5-1, " Guidelines for Fire Protection for Nuclear Power Plants"

4. Appendix A to BTP APCSB 9.5-1

5. Generic Letter 85-01, " Fire Protection Policy," dated January 9, 1985.

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, 2. EVALUATION 2.1 GENERAL This section presents review and evaluation of exemptions or i deviations from 10CFR50.48 or Appendix R to 10CFR50 requested by the Licensee (SCECo) of San Onofra Nuclear Generating Station.

i Evaluation of exemption requests for each fire area / zone singly or

{ collectively follows a format suggested by the NRC and is arranged in the following subsections:

{ o Exemption requested o Discussion o Evaluation o Conclusion.

I The fire area / fire zone numbering used in this section corresponds to that used in the Licensee's submittal (9).

2.2 Reactor Auxiliary Building Lower Level IFire Area 1-AB-(3)-2A1 East Penetration Area fFire Area 1-YD-20-4A1 West Penetration Area (Fire Area 1-YD-20-4B]

Yard Area (Fire Area 1-YD-14-4D]

circulating Water Pump Well [ Fire Area 1-YD-(7)-4E]

Turbine Building Ground Floor (Fire Area 1-TB-8-9Al Turbine' Deck [ Fire Area 1-TB-35-9B1 Control Room Complex [ Fire Area 1-PB-42-161 Power Block Roof [ Fire Area 1-PB-56-33]

2.2.1 Exemptions Requested Exemptions were requested from Section III.G.3 to the extent that it requires installation of fire detection and fixed fire suppression systems in the areas for which an alternative shutdown or dedicated shutdown capability is provided.

2.2.2 Discussion 2.2.2.1 Fire Area 1-AB-(3)-2A This fire area consists of the boric acid injection pump room and the lower level of the reactor building containing the charging pump room, radwaste processing rooms, and the radwaste tank rooms.

The wall separating this area from the pipe tunnel is 3-hour fire

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rated. The ceiling is a precast concrete slab 21 inches thick.

Other below grade walls are 18-inch-thick reinforced concrete. The walls above grade are either 3-hour fire rated, 8-inch, filled concrete block, or 24-inch reinforced concrete. A nonrated door adjoins the yard area from the boric acid injection pump room and a 3-hour rated door cuts off the waste baling room. The ventilation penetrations to the yard area and waste baling room are not provided with fire dampers.

The fire loading in this area is about 4,650 Btu per square foot consisting of cable insulation, miscellaneous plastics, and charging pump lube oil. This fire load represents a fire severity of less than 4 minutes based on the ASTM E-119 fire test curve.

The safe shutdown. equipment and cables located in this area include the charging pumps, charging refueling water storage tank (RWST) isolation valves, motor control center 2A, and associated power and control cables. The safety injection system will be used as the alternative safe shutdown system, and this system is I completely independent of this fire area, both physically and electrically.

Fire protection includes smoke detectors for the charging pump room, motor control center 2A, radwaste control board, radwaste tank rooms, and the boric acid injection pump room. The Licensee I has committed to install a sprinkler system in the charging pump room.

these areas.

Fire extinguishers and fire hose stations are available for

, 2.2.2.2 Fire Area 1-YD-20-4A; Fire Area 1-YD-20-4B; Fire Area 1-YD-14-4D; and Fire Area 1-YD-(7)-4E I These fire areas are all exterior areas that comprise the east penetration area, west penetration area, yard area, and the circulating water pump well.

The two penetration areas (east and west) are bounded by the steel containment sphere, the enclosure building, the turbine building, and the power block or fuel handling building. The yard area is bounded by the vital area fence. The circulating water pump well is open and below grade, but is accessible by two separate staircases.

l The hot safe shutdown components located within the east and west penetration areas include cabling for the following redundant equipment:

PORVs and associated block valves pressurizar level / pressure transmitters primary system temperature transmitters charging loop A control valve / flow transmitter RCP seal flow pressure transmitters steam generator level transmitters

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auxiliary feedwater pumps and flow control valves

TER-C5506-622 thermal barrier outlet valves seal injection flow control valves atmospheric steam dump valves.

A dedicated shutdown ca i and west penetration areas. For pability the east is provided for both penetration thethe area, east i dedicated safe shutdown system will be totally independent (physically and electrically) outside of this area when the Licensee routes new cables for the primary system hotleg temperature instruments. Certain dedicated shutdown system cables are routed through the west penetration area; however, the Licensee is committed to protect them with a 3-hour fire rated barrier.

{- Therefore, for both areas, the dedicated shutdown system will be independent of both penetration fire areas.

The safe shutdown' components located within the yard area (1-YD-20-4B) and the circulating water pump well include:

certain chamical and volume control system components and cables auxiliary feedwater system valves and cables main steam system cables I -

component cooling water system salt water cooling system pumps and cables gaseous nitrogen system components I essential electric systems that include station service transformers 1, 2, and 3 and cables for the 480-V switchgear and 120-V vital buses.

I The dedicated shutdown system diesel generator, shutdown panel, auxiliary feedwater pump, and associated equipment will be housed in a new building now being erected in the northwest section of the yard area.

The station transformers are separated by 150 feet including 40 feet without intervening combustibles. This separation ensures I that a train of the 480-V electrical system remains available without fire damage. Operator action may be required to intertie 480-V switchgear to provide power to redundant switchgear. These M intertie cables are routed outside this fire area and, thus, are U independent. Also, cables for one redundant charging pump will be rerouted outside this area such that a separation distana. of ct I

least 20 feet is maintained. Intervening cable trays will be fire stopped at the boundary of Fire Areas 1-YD-20-4B and 1-YD-14-4D.

If one of the three component cooling water damaged by fire, then the ATW pump, which is more(CCW) than pumps is 100 feet away, will be used as an alternative source. Cables for the Train 1 CCW pump will be wrapped with a 1-hour fire barrier and suppression / detection will be provided at the boundary of the yard area and the west penetration area. If all these (CCW) pumps are damaged by fire, then the motor-driven auxiliary feedwater pump can still be used as an alternate for single phase cooling.

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Cables for the redundant saltwater cooling pumps could be damaged by a fire; however, the auxiliary saltwater cooling pump will be used as an alternative shutdown capability. Operator ,

action will be required to locally control certain valves located

, in and outside of this fire area. Adequate time, from 2 1/2 up to 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br />, is available and so is the manpower to perform the I actions.

In summary, for all of'these yard areas, either dedicated or alternative safe shutdown components / systems are available given fire damage to normal, redundant shutdown components located within these yard areas. Essentially all of the dedicated or alternative shutdown components are located outside the area of concern or are protected by fire rated barriers and suppression systems in accordance with Appendix R. In the cases where alternative I shutdown components are relied upon, certain manual actions are required. The Licensee has stated that adequate time and manpower are available to perform the necessary actions.

l Fire loading in all these areas is negligible to small.

Fire protection for all of these areas includes the I availability of fire hose stations and fire extinguishers.

fire detection has been provided for the following:

Also, I enclosure building east entrance to Fire Areas 1-YD-20-4A and 1-YD-20-4B station service transformers 1, 2, and 3.

Fire suppression systems are provided locally for the following:

all three station service transformers cable trays which pass through the west boundary of Fire Zone 1-YD-2D-4B into the adjacent yard area I .

(1-YD-14-4D).

Other fire protection features include curbing to contain oil spills at the transformers, fire barriers for selected cables, and large spatial separations in open yard areas.

l 2.2.2.3 ' ire Area 1-TB-8-9A i The turbine building ground floor (Fire Area 1-TB-8-9A) has a l 3-hour fire rated north wall, which separates the 4160-V switchgear l room from the turbine building. The lube oil storage shed walls l are also 3-hour fire rated. The wall adjoining the east / west '

penetration areas and the east wall of the 480-V switchgear room are both 1-hour fire rated. The south wall is 3-hour fire rated.

i The remainder of the area walls are constructed of concrete block '

or reinforced concrete. Nonrated doors open to the yard area (1-YD-14-4D). Three-hour fire doors are installed in the 4160-V

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and 480-V switchgear rooms, main transformer area, and the lube oil storage shed.

The fire load is about 110,000 Btu per square foot, which

' translates into a fire severity of 82 minutes as represented by the ASTM E-119 fire test curve. This fire load comes primarily from l the lube oil within the lube oil reservoir. This fire load is  !

protected by an Aqueous Film Forming Foam (AFFF) fire suppression I system. A minor portion of the fire load is from cables.

The safe shutdown components located within this area include:

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auxiliary feed water pumps motor control center (MCC)-3 cabling for normal e safe shutdown systems.

The Licensee has committed to relocate cables and equipment for the auxiliary shutdown panel (C-38) outside of this fire area and to use it as the dedicated shutdown system panel. All I dedicated shutdown system components are outside of and independent of this fire zone. Because the 480-v switchgear room will have some dedicated shutdown components, the 1-hour fire rated wall will I be protected by an automatic fire suppression system to establish a 3-hour rating by direct wetting. Any dedicated shutdown system valves (except reheater isolation valves) requiring a manual action can be operated from outside of this fire area and, therefore, I establishes physical independence. However, operator action will be required in this fire area to close the reheater isolation valves after fire extinguishment. The time available to do this is I 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. This time frame is acceptable based upon previous NRC staff positions concerning time allowed for repairs / actions.

I Fire protection consists of fire detection systems for the following:

lube oil reservior pump and conditioner areas

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hydrogen seal oil unit / emergency air compressor lowest cable trays above lube oil reservior area lube oil reservior area and south end of turbine building.

Fire suppresion systems are installed for the following:

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chemical feed area chemical treatment area: east wall and a portion of 480-V switch gear room south wall, north wall of chemical treatment area, and the structural steel at north and of the fire area lube oil reservoir and conditioner areas cable trays routed in north portion of the area near

lube oil and chemical feed areas hydrogen seal oil unit.

l Portable fire extinguishers and hose stations are available throughout the area.

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i 2.2.2.4 Fire Area 1-TB-35-9B

! This fire area (the turbine deck) is an open outdoor area consisting of the feedwater heater deck (elevation 35 feet) and the turbine deck (elevation 42 feet). Three-hour fire rated walls

! separate the turbine deck from the control room complex.

I Unprotected openings connect this area to the containment, the fuel storage room, new fuel storage room, and the turbine building ground floor.

The fire load is negligible (about 114 Btu per square foot) . ,

{ The safe shutdown components in this fire area are as follows:

pressurizer. pressure transmitter D -

primary system hot leg temperature transmitter M -

turbine stop valves motor and steam driven auxiliary feed water pump auxiliary feed water flow control valves.

Either the dedicated shutdown system instrument panel or an alternative train of safe shutdown equipment will be used in the I event of fire damage. Operator actions may be required regarding certain valves in this fire area after a fire event.

However, it is not absolutely necessary because alternative manual actions elsewhere are available to perform the decired function.

Fire protection consists of smoke detectors located in the high pressure turbine housing. Also, fire extinguishers and hose stations are available within the fire area.

2.2.2.5 Fire Area 1-PB-42-16 and Fire Area 1-PB-56-33 Fire Area 1-PB-42-16 (the control room) is on the third floor of the power block building. The control room walls and floor are I 3-hour fire rated. The roof of the control room has an approximate thickness of 7 1/2 inches of concrete. Doors and ventilation system dampers are 3-hour fire rated. Fire Area 1-PB-56-33 (power block roof) is directly over the control room fire area and is open l to the atmosphere.

d The fire load in the control room is about 78,850 Btu per g square foot, which translates into a fire severity of 60 minutes as represented by the ASTM E-119 fire test curve. This fire loading consists of cable insulation, books, computer paper, desks, and drawing files. The fire loading on the power block roof is negligible.

The control room complex contains the control consoles, vital bus cabinets, and cabling for all safe shutdown systems. The power block roof contains redundant safe shutdown cables. Dedicated safe shutdown capability is provided for the control room and alternative shutdown capability is provided for the power block roof.

TER-C5506-622 Fire protection for the control room consists of fire detection in the techical support center, back panel area, the kitchen, computer room, and within the vital bus and main control console. Fire extinguishers and hose stations are available for j the control room fire area. The power block roof area has a fire '

extinguisher only. )

2.2.3 Evaluation The fire protection in these fire areas does not comply with the technical requirements of section III.G.3 of Appendix R because r fire detection and fixed fire suppression systems have not been installed throughout the area for which an alternative or dedicated

{ shutdown capability is provided.

Q There was a conceNn that a fire in ar.y of the subject fire  !

u areas would damage redundant safe shutdown components such that safe shutdown could not be achieved or maintained. However, with I the exception of Fire Areas 1-TB-8-9A (turbine building ground floor) and 1-PB-42-16 (control room), the fire loads are low (less than 35,000 Btu per square foot) and are well distributed.

Therefore, it is not expected that a fire of significant magnitude or duration would occur. If a fire was to occur, there is reasonable assurance that it would be detected early and extinguished before damaging redundant components.

In the case of Fire Area 1-TB-8-9A, the principal fire hazards are protected by automatic fire detection and suppression systems.

Therefore, given a fire event, it would be extinguished in a timely I manner by either engineered fire suppression systems or the fire brigade before redundant components are damaged.

I The control room (Fire Area 1-PB-42-16) is continuously manned and has partial automatic fire detection capability. Therefore, there is reasonable assurance that given a fire, it would be I detected early. Moreover, because the control room is completely accessible and fire fighting equipment is available to the area, there is reasonable assurance that a fire would be extinguished before redundant components would be damaged.

If a fire should damage redundant safe shutdown system components in Fire Areas 1-AB-3-2A, 1-YD-20-4A, 1-YD-20-4B, 1-TB-8-9A, 1-PB-42-16, or 1-PB-56-33, or cause an evacuation of the

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, control room (1-PB-42-16), the dedicated safe shutdown capability can be used to achieve and maintain safe plant shutdown.

t In the event of fire damage to redundant components in Fire Areas 1-YD-14-40, 1-YD-(7)-4E, and 1-TB-35-9B, the alternative shutdown capability can be used to achieve and maintain safe shutdown. '

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TER-C5506-622 With respect to required manual actions on a post-fire basis, the Licensee has stated that valves will be accessible and mostly operable from outside the area involved with the fire. Also, in the case where it is necessary to re-enter the area involved with the fire, it has been shown that the expected fire severity is low and sufficient time exists to allow for fire extinguishment and i manual action (s). The time factor of 2 1/2 hours as quantified by l the Licensee is conservatively higher than the NRC staff position l t of one hour.

I 2.2.4 Conclusion Based on the above evaluation, it is concluded that the existing fire protection features in conjunction with the proposed modifications and the availability / independence of the dedicated or  !

alternative shutdown chpabilities for the above described fire  !

O areas provide a level of protection equivalent to the technical requirements of Section III.G.3 of Appendix R. Therefore, the examptions should be granted.

2.3 Containment [ Fire Area 1-CO-(10)-11 2.3.1 Exemptions Requested (a) An exemption was requested from Section III.G.3 to the extent that it requires installation of fire detection and fixed fire suppression systems in the areas for which a dedicated shutdown capability is provided. (b) An exemption was requested to the extent that the instruments providing indication at the dedicated shutdown panel and the dedicated shutdown pressurizer are not independent of the fire area under consideration.

2.3.2 Discussion The containment fire area is a steel sphere which houses the I reactor, steam generators, RCPs, RHRs, and other shutdown support systems. The personnel hatches and electrical / mechanical penetrations are not fire rated.

, The fire load is about 23,800 Btu per square foot, which translates into a fire severity of 18 minutes as represented by the ASTM E-119 fire test curve.

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, The safe shutdown systems located inside this fire area include:

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reactor coolant system chemical and volume control system main steam system I -

component cooling water system containment ventilation system.

Separation of the redundant primary system temperature,

! pressure, and pressurizar level, steam generator level instruments, l

TER-C5506-622 pressurizer heaters, and associated cables does not comply with the separation criteria of Appendix R. To compensate for this, the Licensee is committed to utilize a dedicated shutdown system i capability. Cables for the dedicated shutdown system components are located within the containment fire area. These circuits are composed of Rockbestos cables, which have a fire rating of one hour, and are routed in conduits.

Only one steam generator is required for shutdown. Therefore, l the primary tamperature instruments and the steam generator level

- instruments for only one loop need to be available. The instruments that provide indication of primary system temperature and steam generator level at the dedicated shutdown panel are I located within the reinforced concrete structures which house the steam generators. There are no cable trays located within the steam generator cavities eliminating the danger of fire spread I between steam generators.

The Licensee has committed to provide the solenoid valves for PORV (CV-546) and its associated block valva (CV-530) with radiant energy heat shields. The circuits will be Rockbestos cables.

Also, cables for the dedicated shutdown system operation of the pressurizer heater group D are Rockbestos cables. Cables for the instruments providing indication at the dedicated shutdown panel will be Rockbestos cables.

I Instruments which provide indication for pressurizer pressure and level at the dedicated shutdown panel are located in a single cabinet. This cabinet is considered to be a radiant energy heat I shield that separates these instruments from redundant counterparts in adjacent cabinets. All cabinets are located outside of the bioshield wall. Two-inch-thick insulation is provided inside each cabinet. The dedicated shutdown panel instrument circuits are Rockbestos cables routed in conduit.

Ionization detectors are installed over each steam generator, O in the electrical penetration area, over each of the reactor U coolant pumps, and under the pressurizar. Automatic infrared flame detectors are located on the crane rails above the operating floor lg ,

and in the residual heat removal pump area. The Licensee has committed to install a hose connection from the Units 2 and 3 fire main. This connection will provide water to the existing

, suppression systems installed at the reactor coolant pumps (RCP) and the residual heat removal pumps. Also, hose stations and fire extinguishers are available inside containment.

! Each reactor coolant pump has an oil collection system that

,i complies with Section III.0 of Appendix R. Finally, the charcoal fuel load factor is diminished because it is entirely contained g within charcoal filter units and, hence, does not pose a hazard to

,' its surroundings.

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TER-C5506-622 2.3.3 Evaluation l* The technical requirements of Section III.G.3 of Appendix R are not met in this fire area because fire detection and fixed fire I

suppression systems have not been installed throughout the area for I

which a dedicated shutdown system is provided. Further, the requirements of Section III.G.3 are not met because the instruments l providing indication at the dedicated shutdown pressurizer are not '

l independent of the fire area of concern.  !

I There was a concern that a fire in the containment fire area

, could cause the loss of normal safe shutdown capability. However, the fire load in this area is low (about 23,800 Btu per square

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foot). Because of this low fire loading, a fire of significant I magnitude or duration is not expected to occur. To further O mitigate the chance of containment fire damage, each reactor M coolant pump has fire detectors and an oil collection system that complies with Section.III.0 of Appendix R. Also, the charcoal l

I component of the average fire load is totally contained within metal filter units. Hence, there is a reasonable assurance that a fire in these locations will be small, detected early, and i

extinguished by the fire brigade before redundant safety-related i areas are threatened. '

should a fire damage any normal safe shutdown component in the containment fire area before the fire brigade extinguishes the fire, a dedicated safe shutdown system is available to achieve and maintain safe shutdown. However, this system is not independent of the fire area.

I The major shutdown components are well separated within containment and the real issue la that cables for the dedicated shutdown system are not independent of the fire area for which an alternative safe shutdown capability is provided. To compensate for this, the Licenses has selected the use of Rockbestos cables, which have a fire rating of one hour.

There were several concorr.s with the use of fire rated cables (Rockbestos cables) in lieu of a fire rated enclosure or wrap. The first was that, when exposed to the effects of a fire, the cable would not perform its intended function. By letter dated December 31, 1985, the Licensee submitted the results of a fire test l conducted by Underwriter's Laboratories (UL) . In the procedura, representative samples of the cable were subjected to a 1-hour fire endurance and hose stream test in accordance with the method

- prescribed in ASTM E-119. During the fire test and for a period of 93 hours0.00108 days <br />0.0258 hours <br />1.537698e-4 weeks <br />3.53865e-5 months <br /> beyond, electrical measurements were taken to confirm the cable's electrical performance. Therefore, there is reasonable

, assurance that the cables will function as designed until the fire is extinguished. .

With regard to voltage, the Rockbestos cables have been fire tested at voltages of 110 Vac, 480 Vac, and 960 Vac. Therefore, there is no concern about their use at high voltages.

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1 There was also a concern that the heat produced in a fire would cause structural features, such as cable trays, to collapse.

The falling debris might impact the cable and cause its failure.

The Rockbestos cables will be in conduits and well supported.

Also, because of the low fire loading, a fire of significant magnitude or duration is not expected to occur, and falling debris should not be a concern in this fire area. Therefore, the dedicated shutdown conduits should not be pulled down. Because of the low fire loading, insufficient heat will be generated to cause support failure. The fire brigade could easily extinguish the fire using manual equipment.

{ Because the fire-rated cable could be damaged by a fire, there was a concern that this damage would affect the performance of the shutdown functions for.a time period that is significantly longer than the time period for which the function is required. The 0 proposed use of this cable is to provide an independent train of safe shutdown cables for use in the dedicated shutdown system. The cables were subjected to an ASTM E-119 fire test, and the circuit j integrity was maintained and kept functional for a period of 93 hours0.00108 days <br />0.0258 hours <br />1.537698e-4 weeks <br />3.53865e-5 months <br />. Rockbestos cables were previously evaluated and accepted by the NRC for use where a 1-hour fire-rated barrier was required by I Appendix R. This acceptance was granted for the Three Mile Island (TMI) nuclear plant via an NRC letter dated April 19, 1985.

I Because the containment fire loading is low, it would be, in actuality, difficult to achieve a real fire that would result in temperatures approaching the E-119 time-temperature curve over a large portion of the fire area. Prompt action by the fire brigade would further reduce the actual time-temperature fire exposure curve. The UL hose stream tests with repeated application of hose stream forces has resolved the concern of damage or circuit I disruption by the use of hoses. Also, it is believed that the inherent fire resistance of the Rockbestos cables provides a large margin of safety due to the low containment fire load.

There was a concern that thermal expansion forces and post-fire mechanical forces due to fire fighting and recovery operations were not simulated in the test. There was also concern that " wet short" conditions were not simulated (i.e., cables in cable trays may be immersed in water for a significant time). The installation proposed by the Licensee is for conduits, and hose l streams would not disrupt the cables. These cables, being in conduit, would not be immersed in water. Therefore, two concerns are resolved.

2.3.4 Conclusion

• Based on the above evaluation, it is concluded that the existing and committed fire protection features combined with the l dedicated shutdown capability (and the use of Rockbestos cables in lieu of physical independence of the fire area of concern) provide a level of protection equivalent to the technical requirements of

, Section III.G.3 of Appendix R. Therefore, the exemptions should be granted.

TER-C5506-622

3. CONCLUSIONS This section is provided to consolidate the results of the evaluation contained in Section 2 concerning the exemptions requested by the Licenses from the requirements of Section III.G of Appendix R to 10CFR50 for San Onofre Nuclear Generating Station Unit 1. It is not meant as a substitute for the specific conclusions reached in the various subsections of Section 2 to which the reader is referred.

Based on the evaluation, the existing fire protection and/or proposed fire protection modifications provide a level of fire 7 protection equivalent to the technical requirements of Appendix R a and, therefore, the following exemptions from the requirements of Section III.G of Appendix R and should be granted.

1. Fire Area 1-AB-(3)-2A to the extent that fire detection and fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information.

2. Fire Area 1-YD-20-4A to the extent that fire detection and fixed fire suppression is not provided persuant to III.G.3.

Refer to Section 2.2 for further information.

3. Fire Area 1-YD-20-4B to the extent that fire detection and 1 fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information.

4. Fire Area 1-YD-14-4D to the extent that fire detection and I fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information. J

5. Fire Area 1-YD-(7)-4E to the extent that fire detection and fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information.

I 6. Fire Area 1-TB-8-9A to the extent that fire detection and fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information.

7. Fire Area 1-TB-35-9B to the extent that fire detection and fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information. l

8. Fire Area 1-PB-42-16 to the extent that fire detection and fixed fire suppression is not provided pursuant to III.G.3.

Refer to Section 2.2 for further information.

9. Fire Area 1-PB-56-33 to the extent that fire detection and'

! fixed fire suppression is not provided pursuant to III.G.3.

j Refer to Section 2.2 for further information.

• TER-C5506-622 i'

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10. Fire Area 1-CO-(10)-1 to the extent that fire detection and fixed fire suppression and physical independence of the dedicated shutdown system from the fire area of concern is not provided pursuant to section III.G.3.

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4. REFERENCES

1. BTP APCSP 9.5-1 " Fire Protection Program," July 1981 (Standard Review Plan, NUREG-0800)

2. Appendix A to BTP APCSP 9.5-1, " Guidelines for Fire Protection for Nuclear Power Plants Docketed Prior to July 1, 1976," August 23, 1976 I 3. Regulatory Guide 1.120, Fire Protection Guidelines for Nuclear Power Plants," November 1977

4. 10CFR50, " Fire Protection Program for Operating Nuclear Power Plants," November 19, 1980 P 5. Appendix R to 10CFR50, " Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979," November 19, 1980

6. Generic Letter 83-33, "NRC Position on certain Requirements of Appendix to 10CFR50," October 19, 1983

7. Generic Letter 85-01, " Fire Protection Policy," JanuLry 9, 1985

8. Final Work Assignment No. 36, transmitted by M. Carrington (NRC) to Dr. S. Panday (FRC) on July 17, 1985 I 9. Letter from Mark Medford (SCECo) to G. E. Lear (NRC) ,

dated December 31, 1985

10. Requests for Information (RFI), transmitted by N. Ahmed (FRC) to J. Stang (NRC) on December 2, 1985

11. Draft TER, transmitted by N. Ahmed (FRC) to J. Stang (NRC) on April 3, 1986 I

Dated April 21, 1986 l

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