ML20214V793

Safety Evaluation Supporting Exemption from Section Iii.G of App R to 10CFR50

ML20214V793
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	12/01/1986
From:	Office of Nuclear Reactor Regulation
To:
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ML20214E708	List: ML20214E704 ML20214V784 ML20214V793 ML20214V814
References
NUDOCS 8612090835
Download: ML20214V793 (13)

Text

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATIVE TO APPENDIX R EXEMPTIONS REQUESTED BY VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE POWER STATION DOCKET N0. 50-271

1.0 INTRODUCTION

By letter dated April 24, 1985, Vermont Yankee Nuclear Power Corporation (the licensee) requested 11 exemptions from Section III.G of Appendix R to 10 CFR Part 50. On July 16, 1985, the licensee met with the NRC in Bethesda and a request was made of the licensee to provide additional information.

By letters dated July 26, 1985, August 2, 1985, and August 16, 1985, the licensee provided additional or clarifying informa-tion and/or revisions to its submitted exemption requests. By letters dated August 2 and 16, 1985, the licensee subsequently withdrew the following ezemption requests:

o (Fire Zone RB-1) Reactor Building Northwest Corner Room Elevation 232 Feet 6 Inches o

(Fire Zone RB-5 and RB-6) Reactor Building West Side Elevation 280 Feet i

o (Fire Area 13) Turbine Building, Radwaste Building Hallway o

(Fire Area 12) Diesel Fuel Oil Trarisfer Pump Building o

(Fire Area 17) Condensate Storage Tank and Instrument Area By letter dated August 15, 1986, the licensee provided a description of the special circumstances pertaining to the April 24, 1985 exemption request as subsequently modified.

By letter dated October 31, 1985, with a supporting description of special circumstances provided by letter dated June 10, 1986, the licensee requested l

l two additional exemptions from III.G.1.a of Appendix R.

This Safety Evaluation which addresses both sets of exemption requests, is based in part on the attached Technical Evaluation Report (TER) written by theNRRcontractor,FranklinResearchCenter(FRC). The staff has reviewed the TER and agrees with the conclusions reached in the FRC TER.

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Section III.G.1 of Appendix R requires fire protection features to be provided for structures, systems, and components important to safe shut-down, capable of limiting fire damage so that:

a.

One train of systems necessary to achieve and maintain hot shutdown conditions from either the control room or emergency control station (s) is free of fire damage; and b.

Systems necessary to achieve and maintain cold shutdown from either the control room or emergency control station (s) can be repaired within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Section III.G.2 of Appendix R requires that one train of cables and equipment necessary to achieve and maintain safe shutdown be maintained free of fire damage by one of the following means:

a.

Separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a 3-hour rating. Structural steel forming a part of or supporting st:ch fire barriers shall be protected to provide fire resistance equivalent to that required of the barrier.

b.

Separation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.

In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

c.

Enclosure of cable and equipment and associated non-safety circuits of one redundant train in a fire barrier having a 1-hour rating.

In addition, fire detectors and an automatic fire suppression system j

shall be installed in the fire area, If the above conditions are not met,Section III.G.3 requires that there i

be an alternative shutdown capability independent of the room, zone or area of concern.

It also requires that fire detection and a fixed sup-pression system be installed in the ared of concern if it contains a large concentration of cable or other combustibles.

These alternative require-ments are not deemed to be equivalent; however, they provide an acceptable I

level of fire protection for those configurations in which they are approved by the staff.

Because it is not possible to predict the specific conditions under which fires may occur and' propagate, the design-basis protective features rather than the design-basis fire are specified in the rule.

Plant-specific l

features may require protection different from the measures specified in i

Section III.G.

In such a case, the licensee must demonstrate, by means of a detailed fire hazards analysis, that existing protection or existing protection in conjunction with proposed modifications will provide a level of safety equivalent to the technical requirements of Section III.G of l

Appendix R.

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

o The alternative ensures that one train of equipment necessary to achieve hot shutdown from either the control room or emergency control stations is free of fire damage, o The alternative ensures that fire damage to at least one train of equipment necessary to achieve cold shutdown is 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 that provided by either existing or proposed alternatives, o

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

2.0 REACTOR BUILDING, ELEVATION 213 FEET 9 INCHES THROUGH 252 FEET AND 280 FEET (FIRE ZONES RB-1, RB-2, RB-5, AND RB-6) 2.1 Exemption Requested Exemptions were requested from Section III.G.2.b to the extent that it requires installation of an automatic fire suppression system for total area coverage.

l 2.2 Discussion 2.2.1 Fire Zones RB-1 and RB-2) Reactor Building, Torus Area Elevation 213 Feet 9 Inches Fire Zones RB-1 and RB-2 in the reactor building incorporate the entire torus area and corner rooms, except for the reactor core isolation cooling (RCIC) room. The RCIC room is a separate fire area.

Fire Zones RB-1 and RB-2 run from elevations 213 feet 9 inches through 252 feet in the reactor building.

Fire Zone RB-1 includes the " northern" part of the reactor building and is distinguished from Fire Zone RB-2 by two fire separation zones. These separation zones contain no combustible loads on the floor, and the cable trays that run through these separation zones are fire stopped over a 20-foot distance using material and design details that have been tested and approved by a nationally recognized laboratory. This

. fire stopping has no fire rating and it is not used as a fire barrier, i

but it is a Factory Mutual (a nationally recognized independent fire test i

laboratory) approved noncombustible material and application design prevents flame propagation along a cable tray. The cables are totally enclosed with the fire stop material over a 20-foot length.

The torus area is an octagonally shaped room constructed of reinforced concrete. The floor area is about 14,200 square feet and the ceiling height is 37 feet. The net available floor space is small because the containment and the torus fills a large volume of the room.. There is essentially no fire loading on the floor proper and the fixed combustibles consist of cable insulation. The total heat content is about 84,756,000 Btu and is distributed in the form of cables in open trays throughout the area. There are no concentrated fire loads or fire hazards. The average fire load is approximately 5,790 Btu per square foot which translates into i

a fire severity of less than 5 minutes on the ASTM E-119 time-temperature i

curve.

Fire Zones RB-1 and RB-2 (torus area) also contain corner rooms i

and these are described under the northeast and southeast corner rooms in Section 2.2.2 below.

The safe shutdown systems in the torus area include residual heat removal (RHR), RHR service water cables for divisions I and II. Also, core spray, automatic depressurization system (ADS), high pressure coolant injection (HPCI), and instrumentation for division I and core spray, ADS, RCIC, and instrumentation for division II are located in the torus area (Fire Zones RB-1 and RB-2).

Finally, the torus area contains power and control cables for the aforementioned redundant divisions.

The existing fire protection includes smoke detection, fire extinguishers, and manual hose stations. All redundant safe shutdown systems are sepa-rated by 20 feet with no intervening combustibles located within the spatial separation. The licensee proposes to provide fire stopping for the cable trays to create a 20-foot separation zone in the northwest quadrant and providing the dc power feed from the alternative shutdown battery with a 3-hour fire barrier. This fire-stopped separation zone precludes the direct propagation of a fire from Fire Zone RB-1 to' RB-2 and vice versa.

2.2.2 (Fire Zones RB-1 and RB-2) Reactor Building, Northeast and Southeast Corner Rooms Elevation 213 Feet 9 Inches To 252 Feet Both of these rooms are triangular-shaped, have two levels each, and are in opposite corners of the reactor building. The floor area of each room is 800 square feet and runs from elevation 213 feet 9 inches up to 252 feet via an open stairway. The fire load is in the form of cables and lubricants. There is essentially no fire load on the floors proper and construction is reinforced concrete with no combustible finishes.

The walls facing into the torus areas are constructed of concrete. There are no concentrated fire loads or fire hazardous equipment. The total heat content for the combustibles present is about 17,736,000 Btu per room per level. The average fire load is approximately 22,170 Btu per square foot, which translates into a fire severity of less than 20 minutes on the ASTM E-119 time-temperature curve.

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5-The safe shutdown systems in each room are redundant to each other and include a core spray pump, two RHR pumps, two RHR service water pumps, associated piping, valves, and cables. Also, each room has a RHR heat exchanger and associated instrument cable.

The existing fire protection is in the form of fire extinguishers, a fire detection system in the rooms and torus area between the two rooms (except elevation 252 feet), and manual hose stations. Redundant trains of safe shutdown systems are separated by 20 feet with no intervening combusti-bles. The entrances to each room are separated from each other by 100 feet with no intervening combustibles. The licensee committed to provide fire detection on elevation 252 feet for both zones.

2.2.3 (Fire Zones RB-5 and RB-6) Reactor Building East and West Side Instrument Racks Elevation 280 Feet Fire Zones RB-5 and RB-6 are located in the reactor building; RB-5 is in the northern section, and RB-6 is in the southern end, and form a coninon open area with boundaries of reinforced concrete and no combustible finishes. The floor area is about 14,500 square feet. There is essen-tially no fire load on the floor proper. The fire load exists in the form of cable insulation and combustible lubricants. The cable trays are not grouped but are dispersed throughout the zones. The lubricants are located in the motor generator (MG) set area and are protected by an early warning detection, and an automatic foam fire suppression system. The cable insulation represents 61,296,000 Btu and the lubricants 334,400,000 Btu. This produces an average fire load of 27,300 Btu per square foot.

This translates into a fire severity of about 20 minutes on the ASTM E-119 time-temperature curve which is considered low.

The safe shutdown equipment in this area are the division I and II elec-i trical instrument racks. These racks are separated by 30 feet.

l The existing fire protection is in the form of fire extinguishers, fire detection in the MG set area, manual hose stations, and an automatic foam fire suppression system for the MG set. The separation between the racks is 30 feet with a low fire load (6,100 Btu per square feet excluding the MG set area fire load). The licensee proposes to create 20-foot separa-l tion zones by fire stopping cable trays. These separation zones will be from the concrete shield wall to the edge of the set area beam and from the concrete shield wall to the reactor building wall on the west side.

i The licensee has committed to install early warning fire detectors on the ceiling within the 20-foot separation zones described above.

2.3 Evaluation 4

The fire protection in these fire zones does not comply with the technical requirements of Section III.G.2.b of Appendix R because automatic fire suppression systems have not been installed in the zones.

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, The staff's principal concern with the level of fire protection in these locations was that because of the absence of an area-wide automatic fire suppression system, a fire of significant magnitude could develop and damage redundant shutdown-related systems. However, the fire load in these locations is low.

If a fire were to occur, we expect that it would develop slowly, with initially low heat release and slow room temperature rise. The MG set fire hazard is protected by early warning fire detection and an automatic fire suppression system. Because of the presence of the early warning fire detection systems, the fire would be detected in its incipient stages. The alarms from these detectors are annunciated in the control room. The fire brigade would then be dispatched and would extinguish the fire manually using hose lines or portable extinguishers. Until the fire was put out, the 20 feet of spatial separation between the redundant shutdown-related systems will provide sufficient passive protection to provide reasonable assurance that one shutdown division would remain free of fire damage.

Another major factor that reduces the fire risk in these zones is that the redundant safe shutdown system equipment is well separated with either no or low intervening combustibles. This separation distance is at least 50 feet for equipment and at least 20 feet for cables that are routed in these areas. The staff finds that the installation of an area-wide automatic fire suppression system does not significantly increase the level of fire protection in these zones.

2.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed h.

>rotection measures in the above zones provides a level of fire protection equivalent to the techni-cal requirements of Section III.G.2.b of Appendix R.

Therefore, the exemption request for the aforementioned zones should be granted.

3.0 RCIC ROOM ELEVATION 213 FEET 9 INCHES (RCIC ROOM FIRE AREA) 3.1 Exemption Requested An exemption was requested from Section III.G.2.a to the extent that it requires a 3-hour fire rated barrier between redundant trains of safe shutdown equipment.

l 3.2 Discussion The RCIC room is located within the reactor building at elevation 213 feet

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9 inches.

It is a triangular-shaped room constructed of reinforced concrete. The floor area is about 800 square feet. There is no combusti-ble interior finish. Combustibles within the area consist of cables and l

lubricants distributed throughout the room.

The total heat content is about 20,000,000 Btu. This yields an average fire load of 25,000 Btu per square foot, which translates into a fire severity of less than 20 minutes j

on the ASTM E-119 tine-temperature curve.

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.. The RCIC room contains the RCIC system and the alternative safe shutdown panel. The RCIC room contains only division II shutdown cables. The room i

directly above is part of Fire Zone RB-1 and contains division I and II cables. Also, the torus area adjacent to the RCIC room on the same i

-elevation contains both divisions of cable.

Finally, the HPCI system and i

its associated cables (division I) can serve as a separate safe shutdown path to maintain coolant inventory and remove decay heat in the event of the loss of the RCIC system.

The existing fire protection in the RCIC room consists of 3-hour fire rated barriers forming the walls, floor, ceiling, and penetration seals.

The exceptions to this are the steel plate stairway enclosure, equipment 1-hatch, and the steel security door to the torus area.

Fire detection-exists in the RCIC room and both fire detection and fire suppression systems exist in the area directly above. Also, fire detection exists in the torus area adjacent to the RCIC room. Manual hose stations and fire extinguishers are available to the area. Finally, this room is accessible by the fire brigade from two separate access entry points. The licensee proposes to provide fire stopping in the torus area cable trays directly outside and near the steel security door to the RCIC room. This fire stopping has no fire rating, but it is a Factory Mutual approved noncombustible material and application design prevents flame propagation i

along a cable tray.

3.3 Evaluation

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The fire protection in the RCIC room does not comply with the technical requirements of Section III.G.2.a of Appendix R because a complete 3-hour fire rated barrier has not been provided between redundant safe shutdown l

equipment and cables.

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Our principal concern with the level of fire protection in the RCIC room was that because of the absence of a 3-hour fire rated barrier, a fire of significant magnitude could develop and damage safe shutdown cables.

However, there is no significant fire load on the floor area and the cable fire load is low (less than 20 minute severity).

If a fire were to occur, then we expect it would develop slowly, with initially a low heat release j

and slow area temperature rise. The floor, walls, ceiling, and penetra-j tions are 3-hour fire rated barriers. However, the stairway enclosure, a hatch cover, and the security door to the torus area are constructed of steel. This steel construction is substantial since it was designed for a high energy steam line break.

Because of the presence of the early i

warning fire detection system, the fire would be detected in its incipient stages. The alarms from these detectors are annunciated in the control i

room. The fire brigade would then be dispatched'and would extinguish the i

fire using hose lines or portable extinguishers. Until the fire was put out, the steel barriers between the RCIC room and the upper room / torus area would provide sufficient passive protection to provide us with reasonable assurance that one division would remain free of fire damage.

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The licensee stated that the high pressure core injection (HPCI) system a

will be used to safely shutdown the plant if the RCIC pump is damaged due to fire. The HPCI pump and cables are located in a separate fire area independent from the RCIC pumps. The staff finds that the provision of a complete 3-hour fire rated barrier would not significantly increase the level of fire protection in this zone.

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.- 3.4 Conclusion Based on the above evaluation, the staff concludes that the existing and the proposed fire protection measures in the area provide a level of fire,

protection equivalent to the technical requirements of Section III.G.2.a of Appendix R.

Therefore, the exemption for the RCIC room fire area should be granted.

4.0 REACTOR BUILDING NORTHEAST CORNER VITAL MOTOR CONTROL CENTERS (MCCs)

ELEVATION 252 FEET (FIRE ZONES RB-3 AND RB-4) 4.1 Exemptions Requested Exemptions were requested from Section III.G.2.b to the extent that it requires the installation of an automatic fire suppression system in the area and to the extent that it requires 20 feet of separation free of intervening combustibles.

4.2 Discussion Fire Zone RB-3 is in the northernmost portion and Fire Zone RB-4 is in the southern end of the reactor building.

Fire Zones RB-3 and RB-4 have about a 30-foot ceiling height. Construction is reinforced concrete with no combustible interior finishes. Fire Zone RB-3 and RB-4 are separated by the steam tunnel wall on the west side and by a 20-foot separation zone on the east side. This separation zone is free of combustibles on the floor proper, and where cables pass through, they will be provided with a 20-foot-long fire stop using materials and application approved by Factory Mutual. Redundant safe shutdown cables that are routed through separation zones will be provided with a 1-hour fire rated barrier. Also, a separa-tion zone exists on the west side of Fire Zone RB-3 and is adjacent to the steam tunnel wall. However, the steam tunnel wall provides a reinforced concrete barrier between Fire Zone RB-3 and RB-4.

The total floor area of these two' zones is 16,000 square feet. The combustibles present are in the form of cable insulation. The total heat content is about 318,904,000 Btu. The average fire load is about 19.932 Btu per square foot, which translates into a fire severity of less than 15 minutes on the ASTM E-119 time-temperature curve.

The safe shutdown systems that exist within these fire zones include MCC 9D, MCC 89A, MCC 89b, and safe shutdown cables in trays. The MCCs contain control and power feeds for redundant AC motor-operated valves. There is approximately an 18-foot separation between the MCCs in question. Also, two cable trays pass over MCCs 89A and 9D and these trays are 18 feet off the floor and extend 6 feet toward MCC 89b. Other cables are in conduit and there are no in-situ combustibles. There is no redundant safe shut-down equipment in these zones other than the MCCs.

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The existing fire protection is in the form of fire extinguishers, manual hose stations, and a radiant energy heat shield installed between MCC 89A and MCC 89b. This noncombustible shield is 14 feet high and extends out from the wall by 4 feet. Also, fire stops have been installed in all conduits that span the separation zone between the redundant MCCs. The licensee proposes to install an early warning fire detection system in the separation zones and over the MCCs. Also, the licensee proposes to install 20-foot-wide fire stops in all cable trays that cross from Fire Zones RB-3 and RB-4.

This separation zone would prevent fire propagation from one fire zone to the other.

Finally, in the northwest sector of Fire Zone RB-3, a partial area sprinkler system has been installed in the separation zone. The licensee also committed to install a 1-hour fire rated barrier for cables in raceways required for safe shutdown that pass through any of the two separation zones.

4.3 Evaluation The fire protection in these fire zones does not comply with the technical requirements of Section III.G.2.b of Appendix R because automatic fire suppression has not been installed and 20 feet of separation free of intervening combustibles has not been provided between redundant safe shutdown system equipment or cables.

Our principal concern with the level of fire protection in these locations was that because of the absence of an area-wide automatic fire suppression system, a fire of significant magnitude could develop and damage redundant shutdown-related systems, e.g., the MCCs. However, the fire load in these locations is low.

If a fire were to occur, we expect that it would develop slowly, with initially low heat release and slow room temperature o

rise. Because of the presence of the early warning fire detection sys-tems, the fire would be detected in its incipient stages. The alarms from these detectors are annunciated in the control room. The fire brigade would then be dispatched and would extinguish the fire manually using hose lines or portable extinguishers.

Until the fire was put out, the 20 feet of spatial separation between the redundant shutdown-related systems would provide sufficient passive protection to, provide reasonable assurance that one shutdown division would remain free of fire damage. Another major factor that reduces the fire risk in these zones is that redundant safe shutdown system equipment and cables are well separated (except for the vital MCCs which are separated by 18 feet) with either no or low in-situ combustibles, and a large radiant heat shield.

Where redundant safe shutdown cables are routed through separation zones, they will be provided with a 1-hour fire rated barrier.

Finally, in the northwest corner of Fire Zone RB-3, there is a partial area sprinkler system. The staff finds that the installation of an area wide automatic fire suppression system would not significantly increase the level of fire protection in these zones.

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4.4 Conclusions Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed fire protection measures in the above fire zones provides a level of fire protection equivalent to the technical requirements of Section III.G.2.b of Appendix R.

Therefore, l

this exemption request for the aforementioned zones should be granted.

4 5.0 REACTOR BUILDING NORTHWEST CORNER ELEVATION 252 FEET (FIRE ZONE RB-3) 5.1 An exemption was requested from Section III.G.2.b to the extent that it requires 20 feet of separation free of intervening combustibles.

5.2 Discussion Fire Zone RB-3 is located in the northern part of the reactor building and j

measures about 47 by 138 feet, with the 47-foot length being along the northwest perimeter line of the reactor building. Construction is rein-forced concrete with no combustible interior finishes. The ceiling height is 27.5 feet.

Fire Zone RB-3 is separated from Fire Zone RB-4 by the steam tunnel wall on the west side and by a 20-foot separation zone on the east side. This separation zone is free of combustibles on the floor proper, and where cables pass through, they will be provided with a 20-foot-long fire stop using Factory Mutual-approved material and design. The total floor area of Fire Zone RB-3 is about 6,500 square feet. The combustibles present are in the form of cable insulation. The average fire load is negligible.

The safe shutdown systems that exist within Fire Zone RB-3 include MCCs and cables. The issue of redundant MCCs in the northeast corner is addressed in the previous exemption request (see Section 4.0). The cables in question are in the northwest corner and are associated with division II ADS, RHR controls and instruments, and division I HPCI and valve cables. The exposed division I and II cables are separated by only 18 l

feet at their closest point with a low fire load.

The existing fire protection is in the form of fire extinguishers and manual hose stations on an area-wide basis.

Fire stops have been in-l stalled on all cable trays that span the separation zone in the northwest corner. The licensee has provided an early warning fire detection system in the separation zone containing the cables in question. Also, a preaction sprinkler system has been installed beneath the lowest level of l

cable trays and above the top trays throughout the corner area. The licensee proposes to provide a 1-hour fire rated barrier for cables in 4

l raceways required for safe shutdown that pass through the separation zone in the northwest corner of Fire Zone RB-3.

5.3 Evaluation i

The fire protection in this fire zone does not comply with the technical requirements of Section III.G.2.b of Appendix R because 20-feet separation free of intervening combustibles has not been provided between redundant safe shutdown cables.

l 1

. Our principal concern with the level of fire protection in the northwest corner of Fire Zone RB-3 was that because of the absence of a 20-foot separation free of intervening combustibles, a fire of significant magni-tude could develop and damage redundant safe shutdown cables. However, there is no significant fire load on the floor area and the cable fire load is low.

If a fire were to occur, then we expect it would develop slowly, with initially a low heat release and slow area temperature rise.

Because of the presence of the early warning fire detection system, the fire would be detected in its incipient stages. The alarms from these detectors are annunciated in the control room. The fire brigade would then be dispatched and would extinguish the fire using hose lines or portable extinguishers. Until the fire is put out, the 18 feet of spatial separation between the cable trays in question would provide sufficient passive protection to provide us with reasonable assurance that one division would remain free of fire damage. Another major factor that reduces the fire risk in this zone is that redundant cable trays are well separated after diverging from the one point where 18 feet of separation exists. The staff finds that the provision of 20-feet separation free of all intervening combustibles would not significantly increase the level of fire protection in this zone.

5.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed fire protection measures in the above area of Fire Zone RB-3 provides a level of fire protection equiva-lent to the technical requirements of Section III.G.2.b of Appendix R.

Therefore, this exemption request for the aforementioned zone should be granted.

6.0 REPAIRS PERMITTED TO ACHIEVE AND MAINTAIN HOT SHUTDOWN 6.1 Exemption Requested Exemptions were requested from Section III.G.1.a to the extent that it requires one train of systems necessary 'to achieve and maintain hot shutdown conditions from either the control room or emergency control station (s) be free of fire damage. The licensee requested that, rather than being free of fire damage, the following repairs be permitted, if necessary in order to make equipment functional:

(1) Rearranging electrical leads to connect a back-up battery charger in the event a fire in the cable vault disables the operating battery charger; and (2) Replacing fuses that would be blown due to a fire in the cable spreading area.

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4 6.2 Discussion In order to justify allowing the operators to make repairs following a l

fire, the licensee provided information to demonstrate that the repairs were simple and could be quickly completed with materials that were i

readily available. The repairs involve connecting a back-up charger in the event a fire damages the normal battery charger in the cable vault, and replacing fuses that have the potential to be blown due to spurious l

signals resulting from a fire in the cable spreading area.

6.3 Evaluation Procedures require the operator to check the battery charger and fuses i

after a fire to determine if any of these components need replacing.

In both instances the plant procedures require determination of the need for i

such repairs. The procedure for connecting the back-up battery charger include the following:

(1) open the supply breaker to the normal battery charger; i

(2) open the feed breaker from the nonnal battery charger; (3) remove the supply cable from the normal battery charger and connect it to the back-up battery charger; and (4) close the supply breaker for the back-up battery charger.

t The areas involved for these actions are in close proximity to one another require only simple and readily available tools, and the total time needed for the operator to complete these actions is no more than 20 i

minutes.

Since the battery charger is not required to be functional for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and the repairs involved in aligning the back-up battery charger l

are routine, we concur with the licensee that these repairs can be i

accomplished within the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time interval.

The fuse replacement repair involves components in the Reactor Core 3

Isolation Cooling (RCIC) System and the Residual Heat Removal (RHR)

System. The RCIC System is required to be operational within 43 minutes t

of reactor scram. Following a fire that requires reactor scram and implementation of the alternate shutdown system, cperators can reach the control panels within 5 minutes and avoid any fuses being blown arior to operating the transfer / isolation switches. However, in the unlicely event 3

the fire damages all the RCIC System fuses, all the fuses could be re-placed in less than 20 ninutes. The RCIC System components, which must be operable within 43 minutes of reactor scram, are controlled from Panel CP-82-1 located in the RCIC Room on the 213 foot elevation of the Reactor i

Building. This control panel is within a 5 minute walk of the Control Room. Spare fuses for the 125 volt de control circuits of these components are sealed and labeled, and located along with necessary tools in a metal enclosure adjacent to Panel CP-82-1. An additional set of spare fuses will be located in a locked metal enclosure (accessible to operators only) also within the immediate vicinity of Panel CP-82-1.

1

. The RHR System is required to be operational within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> of reactor scram.

In the unlikely event the fire damaged all the RHR System fuses, all the fuses could be replaced in less than 20 minutes. The RHR System components, which must be operable within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />, are controlled from Panel CP-82-1 located on the 280 foot level of the Reactor Building.

Spare fuses for the 120 volt ac control circuits of these components are located, with the spare RCIC System fuses, in the metal enclosure adjacent to CP-82-1 in the RCIC Room (within 5-minute walk from CP-82-1). An additional set of spare fuses will be located in the new locked metal enclosure within the immediate vicinity of Panel CP-82-1.

In the unlikely event a fire damages the RHR and RCIC System fuses, the operator has ample time and materials to replace the fuses. Therefore, we concur with the licensee that fuse replacement is an acceptable repair.

The training and operator performance for the necessary repairs is to be verified by a Region inspection.

6.4 Conclusion Based on the above evaluation, the staff concludes that the exemptions from Appendix R to 10 CFR 50 involving operator actions to replace fuses and connect a back-up battery charge are acceptable. Therefore, this exemption request to permit the above mentioned repairs should be granted.

Principal Contributors: John Stang and Peter Hearn Dated:

December 1, 1986

Attachment:

Technical Evaluation Report k

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e ENCLOStJRE 3 O

FRANKLIN RESEARCH CENTER DIVISION OF ARVIN/CALSPAN L

J TECHNICAL REPORT 20TH & RACE STREETS PHILADELPHIA. PA 19103 TWX 7146701889 TEL (215) 4481000