ML20214E704
| ML20214E704 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/08/1986 |
| From: | Ahmed N, Carfagno, Carfagno S CALSPAN CORP. |
| To: | NRC |
| Shared Package | |
| ML20214E708 | List: |
| References | |
| CON-NRC-03-81-130, CON-NRC-3-81-130 TER-C5506-587, NUDOCS 8604110034 | |
| Download: ML20214E704 (21) | |
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TECHNICAL EVALUATION REPORT NRC DOCKET NO. 50-271 FRC PROJECT C5506 k
NRC LICENSE NO. DPR-28 FRC ASSIGNMENT 36 N RC CONTRACT NO. N RC-03-81-130 FRCTASK 587 n
l l
EVALUATION OF FIRE PROTECTION EXEMPTION REQUESTS a
FROM 10CFR50.48 AND APPENDIX R TO 10CFR50 T
=
S YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION TER-C5506-587 J
Prepared for Nuclear Regulatory Commission FRC Group Leader: N. Ahmed Washington, D.C. 20555 NRC Lead Engineer: J. Stang a
J.
This report was prepared as an account of work spohsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any Information, appa-ratus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.
Prepared eviewed b :
Approved by:
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j D'epartmentplreOr Principa[ Author,SC oste:(/'#N 4T oate: +-P-FG oste:
FRANKLIN RESEARCH CENTER DIVISION OF ARVIN/CALSPAN 20tn & RACE ttattfl.PMILADSLPM4A.P419105 I
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CONTENTS l
Section Title Page 1
INTRODUCTION 1
1.1 Purpose of Review 1
1.2 Generic Background 1
1.3 Plant-Specific Background 3
1.4 Review Criteria.
4 2
EVALUATION 5
2.1 General 5
J 2.2 Reactor Building, Elevation 213 Feet 9 Inches through 252 Feet 0 Inch, and 280
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Feet (Fire Zones RB-1, RB-2, RB-5, and RB-6) 5 2.3 Fire Area RCIC Room 8
2.4 Fire Zones RB-1 (Northwest Corner Room); RB-5, RB-6 (West Side) d Fire Areas 13, 12, 17 10 g
2.5 Fire Zones RB-3, RB-4 (Northeast Corner Vital Q,
MCCs) 10 2.6 Fire Zones RB-3 (Northeast Corner) 12 1
3 CONCLUSIONS 14 4
REFERENCES 16
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TER-C5506-587 6
FOREWORD This Technical Evaluation Report was prepared by Franklin Research Center (FRC) under a contract with the U.S. Nuclear Regulatory Commission (Office of Nuclear Reactor Regulation, 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 TER-C5506-587 1.
INTRODUCTION 1.1 PURPOSE OF REVIEW 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 Yankee Nuclear Power Corporation's (VYNPC) Vermont Yankee Nuclear
)
Power Station.
This evaluation was performed with the following l-objectives
- 1 o
To assess if each exemption request demonstrates an equivalent level of overall protection of plant safe
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shutdown capability following a disabling fire event o
To determine the bases for acceptance or denial of each exemption request u
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o To recommend the minimum level of fire protection the applicant or licenses should provide to achieve an equivalent level of fire protection in case a request is m
denied.
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1.2 GENERIC BACKGROUND
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Following a major fire at the Browns Ferry Nuclear Station in u
March 1975, the NRC established a Special Review Group which initiated an evaluation of the need for improving the fire a
protection programs at all nuclear power plants.
The group found
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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-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
'T 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.
Guidance 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 most of the guidelines in Appendix A.
However, the fire protection program has had some significant problems with implementation.
To A
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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8 TER-C5506-587 i
I described as setting out minimum fire protection requirements for the unresolved issues.
The fire protection features addressed included protection of safe shutdown capability, emergency j'
lighting, fire barriers, associated circuits, reactor coolant pump lubrication system, and alternate shutdown systems.
On February 17, 1981, the final rule 10CFR50.48 [4] and i
Appendix R to 10CFR50 [5] became effective, replacing the proposed rule.
Only three of the 15 items in Appendix R were of such safety significance that they should apply to all plants, including those for which alternative fire protection actions had been approved Previously by the staff.
These items are protection of safe
- r-shutdown capability (including alternate shutdown systems),
emergency lighting, and the reactor coolant pump lubrication system.
Accordingly, the final rule required all reactors licensed J
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 1
than the proposed rule because Item III.G now provides three
'j 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
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alternative from 50 feet to 20 feet.
In addition, the rule now 4
provides an exemption procedure which can be initiated by a I
licensee's assertion that any required fire protection feature will not enhance fire protection safety in the facility or that such modifications may be detrimental to overall safety.
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- s In summary,Section III.G is related to fire protection 3 p" -
features for ensuring that systems and associated circuits used to i
achieve and maintain safe shutdown are free of damage.
Either fire
'.i protection configurations must meet the specific requirements of Section III.G or an alternative fire protection configuration must
,J be justified by a fire hazard analysis.
Generally, the staff will accept an alternative fire protection configuration if:
,q The alternative ensures that one train of equipment o
necessary to achieve hot shutdown from either the control g
room or emergency control stations is free of fire damage.
b The alternative ensures that fire damage to at least one o
train of equipment necessary to achieve cold shutdown is l}
limited so that it can be repaired within a reasonable time lf (minor repairs using components stored on the site).
b o
Fire-retardant coatings are not used as fire barriers.
F o
Modifications required to meet Section III.G would not i
enhance fire protection safety levels above those provided 3
by either existing or proposed alternatives.
P o
Modifications required to meet Section III.G would be detrimental to overall facility safety.
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TER-C5506-587 Guidance tho the industry and the NRC positions on certain requirements of Appendix R is covered by various documents, one of 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.
f Following the promulgation of the final rule, licensees and applicants have requested exemptions and deviations from Appendix R to 10CFR50.
The exemptions and deviations are in the form of a 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 1
i protection of plant safe shutdown capability.
Franklin Research Center (FRC) was to provide technical assistance to the NRC within
,4 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.
lJ Subtask 2:
Review and evaluate each exemption or deviation request submitted by the licensees or the
$y applicants and all additional information provided for conformance with acceptance criteria.
Prepare l
final Technical Evaluation Report (TER) with recommendations, and their basis in support of i
granting or denying the exemption / deviation request.
1.3 PLANT-SPECIFIC BACKGROUND By letter dated April 24, 1985 (9), Vermont Yankee Nuclear
'r Power Corporation (the Licensee) requested 11 exemptions from Section III.G of Appendix R to 10 CFR Part 50.
By letters dated July 26, 1985 (10), August 2, 1985 (11), and August 16, 1985 (12),
the Licensee provided additional or clarifying information and/or 1,
revisions to their submitted exemption requests.
By letters dated August 2 (11) and August 16 (12), 1985, the Licenses subsequently l
withdrew exemptions requests numbered 3, 8,
9, 10, and 11.
The Request for Information (RFI) required in satisfaction of Subtask 1 was transmitted to the NRC on October 4, 1985 (13).
This i:
RFI did not identify any items of additional information required, and as such no site visit was conducted.
l The draft TER (14) was issued to NRC on January 15, 1986.
The contents of the draft reflected the information contained in the Licensee's submittals identified above.
The final TER incorporates all comments received from NRC to date.
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TER-C5506-587 r.
1.4 REVIEW CRITERIA The criteria used in reviewing the Licensee-submitted exemption requests are based on the following documents:
1.
Fire Protection Program for Operating Nuclear Power Plants, 10CFR50.48 2.
Appendix R to 10CFR50
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Standard Review Plan, NUREG-0800, Branch Technical 3.
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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TER-C5506-587 p.
2.
EVALUATION 1
2.1 GENERAL This section presents review and evaluation of exemptions or deviations from 10CFR50.48 or Appendix R to 10CFR50 requested by the Licensee (VYNPC) of Vermont Yankee Nuclear Power Station.
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
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o Evaluation
'l o
conclusion.
f The fire area / fire zone numbering used in this section j'
corresponds to that used in the Licensee's submittal (9).
2.2 Reactor Building, Elevation 213 Feet 9 Inches through 252 Feet 0 Inch, and 280 Feet (Fire Zones RB-1, RB-2, RB-5, and RB-6) 2.2.1 Exemptions Requested Exemptions were requested from Section III.G.2.b to the extent that it requires installation of total area coverage automatic fire suppression systems.
2.2.2 Discussion i
2.2.2.1 Fire Zones RB-1 and RB Reactor Building,
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Torus Area Elevation 213 Feet, 9 Inches l'
Fire Zones RB-1 and RB-2 in the reactor building incorporate the entire torus area and corner rooms, except for the RCIC room.
l' The RCIC room is a separate fire area.
Fire Zones RB-1 and RB-2 l.
run from elevations 213 feet, 9 inches through 252 feet in the reactor building.
Fire Zone RB-1 includes the " northern" part of is the reactor building and is distinguished from RB-2 by two fire
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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.
This L
fire stopping has no fire rating, but it is a Factory Mutual approved noncombustible material and application design that t
prevents flame propagation along a cable tray.
The cables are J
totally enclosed with the fire stop material over a 20-foot length.
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l The torus area is an octagonally shaped room constructed of L
reinforced concrete.
The floor area is about 14,200 square feet l
and the ceiling height is 37 feet.
The not available floor space L
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TER-C5506-587 is small because the containment and the torus fill 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 a fire severity of less than 5 minutes on the ASTM E119 time-temperature curve.
Fire Zones RB-1 and RB-2 (torus area) also contain corner rooms and these are described under the northeast and southeast corner room heading (Section 2.2.2.2).
The safe shutdown systems in the torus area include RHR, and i
RHR service water cables for divisions I and II.
Also, core spray l
ADS HPCI and instrumentation for division I and core spray ADC 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
- o and control cables for the aforementioned redundant divisions.
p!lj The existing fire protection includes smoke detection, fire extinguishers, and manual hose stations.
All redundant safe shutdown systems are separated by 20 feet with no intervening i
combustibles located within the spatial separation.
The Licensee
) 3 is committed to provide fire stopping for the cable trays to l]
create a 20-foot separation zone in the northwest quadrant and to
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provide the dc power feed from the alternative shutdown battery u
with a 3-hour fire barrier.
This fire-stopped separation zone precludes the direct propagation of a fire from zone RB-1 to RB-2 and vice versa.
2.2.2.2 Fire Zones RB-1 and RB Reactor Building, I
Northeast and Southeast Corner Rooms Elevation 213 Feet, 9 Inches through 252 Feet l
Both of these rooms are triangular-shaped, have two levels
'1 each, and are in opposite corners of the reactor building.
The t
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 I
concrete with no combustible finishes.
The walls facing into the torus areas are constructed of concrete.
There are no concentrated
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fire loads or fire hazards.
The total heat content of the p
combustibles present is about 17,736,000 Btu per room per level.
The average fire load is approximately 22,170 Btu per square foot,
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which translates into a fire severity of less than 20 minutes on j
the ASTM E119 time-temperature curve.
l The safe shutdown systems in each room are redundant to each other and include a core spray pump, two RHR pumps, two RHR service L
water pumps, associated piping, valves, and cables.
Also, each room has a RHR heat exchanger and associated instrument cable.
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TER-C5506-587 I
The existing fire protection is in the form of fire extinguishers, a fire detection system in the rooms and torus area
- r 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 combustibles.
The entrances to each room are separated from each other by 100 feet with no intervening combustibles.
The Licensee has made a commitment to provide fire detection on elevation 252 feet for both zones.
lI 2.2.2.3 Fire Zones RB-5 and RB Reactor Building East and West Side Instrument Racks Elevation 280 Feet l
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.
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They form a common open area with boundaries of reinforced concrete and no combustible finishes.
The floor area is about 14,500 square 4
feet.
There is essentially no fire load on the floor proper.
The l[T fire load exists in the form of cable insulation and combustible
'!d lubricants.
The cable trays are not grouped but are dispersed.
The lubricants are located in the MG set area and are protected by Ir a berm, an early warning detection, and an automatic foam fire
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suppression system.
The cable insulation represents 61,296,000 Btu i
and the lubricants 334,400,000 Btu.
This produces an average fire load of 27,300 Btu per square foot, which translates into a fire 1
.Q severity of about 20 minutes on the ASTM E-119 time-temperature
,u curve.
g The safe shutdown equipment in this area is the division I and
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II electrical instrument racks.
These racks are 30 feet apart.
The existing fire protection is in the form of fire t
extinguishers, fire detection in the MG set area, manual hose J
stations, and an automatic foam fire suppression system for the MG set.
The separation between the racks is 30 feet with a low fire l~
load (6,100 Btu per square feet excluding the MG set area fire i
load).
The Licensee is committed to create 20-foot separation zones by fire stopping cable trays.* These separation zones will be from the concrete shield wall to the edge of the MG set area berm and from the concrete shield wall to the reactor building wall on the west side.
The Licensee has made a commitment to install early warning fire detectors on the ceiling within the 20-foot f
separation zones just described.
2.2.3 Evaluation f
l 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
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in the zones.
The principal concern with the level of fire protection in l
these locations was that, because of the absence of an area-wide i
automatic fire suppression system, a fire of significant magnitude l.
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However, the fire load in these locations is low.
If a fire were to occur, it is expected 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 j
j 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
{j detectors are annunciated in the control room.
The firs brigade
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would then be dispatched and would extinguish the fire.
Until the fire is put out, the 20 feett 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.
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Another major factor that reduces the fire risk in these zones is that the redundant safe shutdown system equipusnt is well separated with either no or low intervening co_nbustibles.
This a
1 separation distance is at least 50 feet for equipment and at least-t 7 20 feet for cables that are routed in these areas.
It is found 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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2.2.4 Conclusion l
Based on the above evaluation, it is concluded that the existing fire protection combined with the committed fire i
protection measures in the above zones provides a level of fire protection equivalent to the technical requirements of Section III.G.2.b of Appendix R.
Therefore, the exemption request for the aforementioned zones can be granted.
2.3 RCIC Room Elevation _213 Feet, 9 In: hee (RCIC Room Fire Area) 7 2.3.1 Exemptions Requested j
An exemption was raquested from Section III.G.2.a to the 1,.
extent that it requires a 3-hour fire rated barrier between redundant trains of safe shutdown equipment.
l 2.3.2 Discussion if The RCIC room is located within the reactor building at elevation 213 feet, 9 inches.
It is a triangular-shaped room a
constructed of reinforced concrete.
The floor area is about 800 square feet.
There is no cor.bustible interior finish.
combustibles within the area consist of distributed cables and 1
I lubricants.
The total heat content is about 20,000,000 Btu.
This yields an average fire load of 25,000 Btu per oquare foot, which translates into a fire severity of less than 20 minutes on l
the ASTM E-119 time-temperature curve.
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- l The RCIC room contains the RCIC system and the alternative safe shutdown panel.
The RCIC room contains only division II shutdown cables.
The room 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 elevation contains both divisions of cable.
The existing fire protection in the RCIC room consists of 3-hour fire rated barriers forming the walls, floor, ceiling, and ii penetration seals.
The exception to this is the nteel plate stairway enclosure, equipment hatch, and the steel security door to
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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 extin-guishers are available to the area.
Finally, this room is accessible to the fire brigade from two separate access entry pointse The Licensee is committed to provide fire stopping in the torus area cable trays directly outside and near the steel security iw door to the RCIC room.
This fire stopping has no fire rating, but it is a Factory Mutual approved noncombustible material and n
application design that prevents flame propagation along a cable ly tray.
2.3.3 Evaluation The fire protection in the RCIC room dcas 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 equipment and cables.
The 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 co'. tid develop and damage safe shutdown cables.
However, there is no significant fire load
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on the floor area and the cable fire load is low (less than 20 minute severity).
If a fire were to occur, then it is expected to develop slowly, with initially a low heat release and slow area 1
temperature rise.
The floor, walls, ceiling, and penetrations 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 f-since it was designed for a high energy steam line break.
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.
Until the fire is put out, the steel barriers between the RCIC room and the upper room / torus area will provide r
j sufficient passive protection to provide reasonable assurance that one division would remain free of fire damage.
It is found that the provision of a complete 3-hour fire rated barrier would not significantly increase the level of fire protection in this Zone. _ _ _
TER-C5506-587 t
2.3.4 Conclusion I
Based on the above evaluation, it is concluded that the existing and the committed fire protection measures in the area (cable tray fire stops) 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 can be granted.
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2.4 Fire Zone RB Reactor Building Northwest Corner Room Elevation 232 Feet 6 Inches Fire Zones RB-5 and RB Reactor Building West Side Elevation 280 Feet Fire Area 13 - Turbine Building, Radwaste Building Hallway Fire Area 12 - Diesel Fuel 011 Transfer Pump Buildinq Fire Area 17 - Condensate Storage Tank and Instrument Area By letters dated August 2 (11] and August 16 (12), 1985, the t
Licensee withdrew the exemption requests for these zones and areas.
,u 2.5 Reactor Building Northeast Corner Vital MCCs Elevation 252 Feet (Fire Zones RB-3 and RB-4) 2.5.1 Exemptions Requested Exemptions were requested frem Section III.C.2.b to the extent l~
that it requires the installation of an automatic fire suppression
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system in the area and to the extent that it requires 20 feet of separation free of intervening combustibles.
2.5.2 Discussion T~
2.5.2.1 Fire Zones RB-3 and RB Reactor Building Northeast Corner Vital MCCs Elevation 252 Feet RB-3 is in the northernmost portion and RB-4 is in the i'
southern end of the reactor building.
Construction is reinforced I
concrete with no combustible interior finishes.
RB-3 and RB-4 are
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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 6
free of combustibles on the floor proper, and where cables pass L
through, they will be provided with a 20-foot-long fire stop using l
materials and application approved by Factory Mutual, which is a nationally recognized fire test laboratory.
Redundant safe l
shutdown cables that are routed through separation zones will be provided with a 1-hour fire rated barrier.
Also, a separation zone exists on the west side of RB-3 and is adjacent to the steam tunnel wall.
However, the steam tunnel wall provides a reinforced concrete barrier between RB-3 and RB-4.
The total floor area of these two zones is 16,000 square feet.
The combustibles present.
TER-C5506-587 are in the form of cable insulation.
The total heac 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 li 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 r
and extend 6 feet toward MCC 89b.
Other cables are in conduit and there are no in situ combustibles.
There is no redundant safe shutdown equipment in these zones other than the MCCs.
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
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noncombustible shield is 14 feet high and extends out from the n
Jall by 4 feet.
Also, fire stops have been installed in all conduits that span the separation zone between the redundant MCCs.
The Licensee is committed to install an early warning fire detection system in the separation zones and over the McCs.
Also, the Licensee is committed to install 20-foot-wide fire stops in all cable trays that cross 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 RB-3, a
partial area sprinkler system has been installed in the
- g separation zone.
The Licensee also has made a commitment to
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install a 1-hour fire rated barrier for cables in raceways required for safe shutdown that pass through any of the two separation zones.
2.5.3 Evaluation
]
The fire protection in these fire zones does not comply with j
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.
]
The principal concern with the level of fire protection in
- I 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 chutdown-related systems, e.g.,
the MCCs.
However, the fire load in these locations is low.
If a fire were to occur, it is expected that it would develop slowly, with initially low heat release and slow room temperature rise.
.l Because of the presence of the early warning fire detection sys-I 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.
Until the fire is put out, the 20 feet of spatial.
TER-C5506-587 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 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.
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.
It is found that the installation of an area-wide automatic fire suppression system would not significantly increase the level of fire protection in these zones.
2.5.4 Conclusion
~
Based on the above evaluation, it is concluded that the 2
existing fire protection combined with the committed fire protection measures in the above fire zones provides a level of 7
fire protection equivalent to the technical requirements of Section
/
III.G.2.b of Appendix R.
Therefore, this exemption request for the aforementioned zones can be granted.
2.6 Reactor Building Northwest Corner Elevation 252 Feet, O Inch (Fire Zone RB-3) 2.6.1 Exemptions Requested An exemption was requested from Section III.G.2.b to the extent that it requires 20 feet of separation free of intervening f
combustibles.
2.6.2 Discussion Fire Zone RB-3 is located in the northern part of the reactor building and measures about 47 by 32 feet, with the 47-foot length being along the northwest perimeter line of the reactor building.
Construction is reinforced concrete with no combustible interior finishes.
The ceiling height is 27.5 feat.
Fire Zone RB-3 is separated from 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 combus*cibles on the floor proper, and where cables pass through, they will be provided with a 20-foot-long fire stop it using FM-approved material and design.
The total floor area of RB-3 is about 8,000 square feet.
The combustibles present are in the form of cable insulation.
The average fire load is 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 Fire Zone RB-3 include MCCs and cables.
The issue of redundant MCCs in the northeast corner is addressed in the previous exemption request l i
TER-C5506-587 2.5.
The cables in question are in the northwest corner and are associated with division II ADS, RHR controls and instruments, and I
division I HPCI and valve cables.
The exposed division I and II cables are separated by only 18 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 installed on all cable trays that span the j
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 cable trays and above the top trays throughout the corner area.
The Licensee is committed to provide a 1-hour fire rated barrier LD for cables in raceways required for safe shutdown that pass
?
through the separation zone in the northwest corner of RB-3.
2.6.3 Evaluation
'N 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.
- n The principal concern with the level of fire protection in the iy northwest corner of Fire Zon3 RB-3 was that, because of the absence j
of a 20-foot separation free of intervening combustibles, a fire of significant magnitude could develop and damage redundant safe l
l 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 it is expected to develop slowly, with initially a low Q
heat release and slow area temperature rise.
Because of the D
presence of the early warning fire detection system, the fire would be detected in its incipient stages.
The alarms from these detectors are annuniciated in the control room.
The fire brigade l
would then be dispatched and would extinguish the fire.
Until the fire is put out, the 18 feet of spatial separation between the cable trays in question will provide sufficient passive protection to provide 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 y
are well separated after diverging from the one point where 18 feet of separation exists.
It is found that the provision of 20-feet separation free of all intervening combustibles would not significantly increase the level of fire protection in this zone.
2.6.4 Conclusion Based on the above evaluation, it is concluded that the existing fire protection combined with the committed fire protection measures in the above area of Fire Zone RB-3 provides a level of fire protection equivalent to the technical requirements of Section III.G.2.b of Appendix R.
Therefore, this exemption request for the aforementioned zone can be granted. _ _ _ _ _ _ _ _ _ _ _
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TER-C5506-587 s
3.
CONCLUSIONS This section is provided to consolidate the results of the evaluation contained in Section 2 concerning the exemptions requested by the Licensee from the requirements of Section III.G of Appendix R to 10CFR50 for Vermont Yankee Nuclear Power Station.
It is not meant as a substitute for the specific conclusions reached in the various subsections of Section 2 for which the reader is referred to specific subsections.
r Based on the evaluation, the existing fire protection and/or proposed fire protection modifications in the aforementioned areas provide a level of fire protection equivalent to the technical requirements of Section III.G of Appendix R and, therefore, the following exemptions from the requirements of Section III.G of Appendix R are deemed reasonable and can be
- granted, f
Reactor Building Torus Area Elevations 213 feet, 9 inches o
and 232 feet, 6 inches (Fire Zones RB-1 and RB-2) to the extent that an automatic fire suppression system is not
- i installed in the zones pursuant to III.G.2.b.
Section 2.2
- 2 provides additional information.
, Q o
RCIC Room Elevation 213 feet, 9 inches (RCIC Room Fire 4
!U Area) to the extent that this area be separated by 3-hour fire rated barriers from the areas containing redundant a
shutdown system equipment, cables, and associated circuits
- g, pursuant to III.G.2.a.
See Section 2.3 for additional information.
Reactor Building, Northwest Corner Room Elevation 232 feet, o
1 6 inches (Fire Zone RB-1) WITHDRAWN BY THE LICENSEE.
- r' o
Reactor Building Northeast and Southeast Corner Rooms i ['
Elevations 213 feet, 9 inches through 252 feet (Fire Zones RB-1 and RB-2) to the extent that automatic fire suppression systems are not installed within the corner
.f.
rooms and within the area between the stairs at elevation 252 feet and the corner rooms pursuant to III.G.2.b.
Section 2.3 provides additional information.
o Reactor Building Northeast Corner Vital MCCs Elevation 252 feet (Fire Zones RB-3 and RB-4) to the extent that automatic fire suppression is not installed in the vital t
MCC area and to the extent that 20 feet of separation without intervening combustibles is not provided between redundant safe shutdown systems pursuant to III.G.2.b.
See Section 2.5 for additional information.
o Reactor Building Northwest Corner Elevation 252 feet (Fire Zone RB-3) to the extent that 20 feet of separation is not 4
.._.._._m_
TER-C5506-587
,,e provided between redundant safe shutdown systems pursuant to III.G.2.b.
See Section 2.6 for additional information.
o Reactor Building East Side Instrument Racks Elevation 280 feet (Fire Zones RB-5 and RB-6) to the extent that automatic fire suppression system is not installed in the 4
zones pursuant to III.G.2.b.
Section 2.2 provides additional information.
~
Reactor Building West Side Elevation 280 feet (Fire Zones o
RB-5 and RB-6) WITHDRAWN BY THE LICENSEE AND INCORPORATED INTO REACTOR BUILDING EAST SIDE INSTRUMENT RACKS ELEVATION 280 FEET (FIRE ZONES RB-5 AND RB-6).
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Turbine Building - Radwaste Building Hallway (Fire Area 13) o WITHDRAWN BY THE LICENSEE.
Diesel Fuel Oil Transfer Pump Building (Fire Area 12) o J
WITHDRAWN BY THE LICENSEE.
o Condensate Storage Tank and Instrument Area (Fire Area 17)
WITHDRAWN BY THE LICENSEE.
D D.
E J
I i
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TER-C5506-587 J
4.
REFERENCES f
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
'l 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 5.
Appendix R to 10CFR50, " Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979," November 19, 1980 i
j 6.
Generic Letter 83-33, "NRC Position on Certain Requirements of Appendix to 10CFR50," October 19, 1983 m
7.
Generic Letter 85-01, " Fire Protection Policy," January 9, 1985 8
Final Work Assignment No. 36, transmitted by M. Carrington (NRC) to Dr.
S.
Pandey (FRC) on July 17, 1985 W
R 9.
Vermont Yankee Nuclear Power Corporation Transmittal to NRC 2
j[].
titled, " Vermont Yankee Exemption Requests From 10CFR50, Appendix R" dated April 24, 1985.
I 10.
Letter from Mr. W. D. Hinkle (Vermont Yankee Nuclear Power Corporation) to Mr. Robert Hermann (NRC), dated July 26, 1985.
[
11.
Letter from Mr. W. D. Hinkle (Vermont Yankee Nuclear Power jL Corporation) Mr. Robert Hermann (NRC), dated August 2, 1985.
.gv 12.
Letter from Mr. W. D. Hinkle (Vermont Yankee Nuclear Power l[.
Corporation) to Mr. Robert Hermann (NRC), dated August 16, 1985.
! E 13.
Requests for Information (RFI), transmitted by N. Ahmed (FRC) to J. Stang (NRC) on October 4, 1985.
14.
Draft TER, transmitted by N. Ahmed (FRC) to J. Stang (NRC) on January 15, 1986.
1 Dated i,,
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