ML20029B201

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Safety Evaluation Re Granting Request for Exemption from Requirements of 10CFR50,App R
ML20029B201
Person / Time
Site: Quad Cities  
Issue date: 02/25/1991
From:
Office of Nuclear Reactor Regulation
To:
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ML20029B200 List:
References
NUDOCS 9103060188
Download: ML20029B201 (2)
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l

REVIEW OF EXEMPTIONS TO APPENDIX R COMMONWEALTH EDISON COMPANY f

QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 DOCKET NOS. 50-254 ANC 50-265 i

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1.0 INTRODUCTION

l ByletterdatedSeptember30} October 1,andNovember 23, 1987, Commonwealth Edison Company (the licensee requested exemptions from certain technical provisions of Appendix R to 10 CFR Part 50 for Quod Cities Nuclear Power Station, Units 1 and 2.

By letter _ dated April 11, 1990, the licensee requested modifications in combustible loading definitions that were used_in exemption requasts tN:t had been submitted on June 25, 1986 and approved on July 21, 198E.

2.0 DISCUSSION The licensee's requests have been reviewed by the staff with the assistance of its contractor Science Applications International Corporation (SAIC). The attached Technical Evaluation Report, dated November 20, 1990, contains SAIC's j

evaluation of the licensee's requests.

i The following exemption requests have been reviewed:

1.

Exemption from Section Ill G.2.b of Appendix R - 20 feet of horizontal space free of intervening combustibles and area wide-suppression-is not provided within the fire area containing redundant reactor vessel l

1evel indicating instruuntation of eacn unit.

2.

Exemption from Section Ill.G.2.b of Appendix R - Adequate separation is not provided between redundant Suppression Pool 1.evel Indicators for Fire Areas RB-1 and RB-2.

Detection and suppression are also not i

provided.

3.

Exemption from Section III.J of Appendix R - Emergency lights are not provided for the suppression pool level sight glasses for Unit 1 and 2.

j 4

Exemption from Appendix R - Fuse pulling, which could constitute a

" repair," is required to prevent spurious equipment operation during hot shutdown.

l S.

Change in combustible loading from.a previously-approved Exemation -

I The combustible loadings in five areas have been increased; tie highest i

loading has been increased to 40,000_ Btu /ft2'.

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i 3.0 EVALUATION The staff has reviewed the five requests made by the licensee. The staff's item-by-item evaluation follows:

1.

Based on the multiple locations within the reactor building where vessel level can be monitored and the existing separation of the level instru-ments and sensing lines, this request is considered acceptable.

2.

Based on the low likelihood that a fire on the torus level would damage the sight glass, and that the fire brigade would be able to control any fire and remove the smoke in sufficient time for when the Suppression Pool Level Indicators would be needed, this request is considered-acceptable.

3.

Based on the time available for the operators to obtain portable lights, this request is considered acceptable.

4 Since the fuse pulling can be accomplished easily and quickly, and would be done in only limited instances, this request is considered acceptable.

5.

Since the new combustible loadings still do not present any additional concerns other than those previously addressed by the staff, the previous NRC approval is not affected. Thus, this request is acceptable.

4.0 CONCLUSION

Based on the staff's evaluation, the exemptions requested in the licensee's letters of September 30, October 1, and November 23, 1987, and-the revised combustible loadings contained in the licensee's April 11, 1990 letter, are considered acceptable, principal Contributor:

D, Notley Date:

February 25, 1991 l

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4 SAIC 90/1076 TECHNICAL EVALUATION REPORT I

OUAD CITIES STATION UNTTS 1 AND 2 REQUEST FOR EXEMPTIONS FROM 10 CFR 50 APPENDIX R TAC NOS. 6704/15 AND MODIFICATION OF COMBUSTIBLE LOADING CRITERIA TAC NOS. 76510/11 1

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SNT Science AppIIcstions Internations! Corporation An Employee Owned Corrpany I

4 November 20,1990 i

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~MW J U JJ Post Ottoce Bos 1303.1710 Goododge Drive, McLean, Vrginia 22102 (703) 8214300

i TABLE OF CONTENTS Section hge FO REWO R D..................................................... 11 1.0 INTRO D U CTI ON..............................................

1 1.1 Pu rpose o f R e vie w..........................................

1 1.2 G e ne ric Ba ckground..............................._..........

I 1.3 Plant Specific Background.....................................

3 1.4 R e vi e w Cri te ri a............................................

4 2.0 E VALU AT10 N................................................. 6 2.1 Separation of Redundant Reactor Level Indicating Instrumentation _......,

6 2.1.1 E x e m o t i o n R e a u e s t e d..................................

6 2.1.2 D i s cu s s i o n...........................................

6 2.1.3 Eval u a t i o n...........................................

7 2.1.4 co n cl u si o ns..........................................

9 2.2 Separation of Redundant Suppression Pool 12 vel Indicators...........

9 2,2.1 Ex e mo tio n R e a u e ste d.................................,

9

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2.2.2 D i s cu s s i o n...,......................................,

9 2.2.3 Evaluation...................

4 10 2.2.4 Conclusion 11 1

2.3 Lack of Emergency Lighting for Suppression Pool level Instrumentation.

11 2.3.1 Exemntion Reau ested................. -................

11 i

2.3.2 D i s cu s si o n... '.......................................

11 2.3.3 Evalu a tio n.,.........................................

11 i

2.3.4 Conclusion 12 2.4 Pulling of Fuses for Hot Shutdown............................ l12 I

2,4.1 Ex e mo tio n R e a u e s te d................................,

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- 2.4.2 D i s cu s s i o n.., ',......,................................

12 4

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2,4.3 E v al u a ti o n..........................................

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2.4.4 Conclusion 14 1

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2.5 Modification in Combustible 1.oading Calculations.................

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i 2.5.1 ' D is cu s s i o n...........................,..............

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2.5.2 E val u a t i o n..........................................

14' 15 2.5.3. Conclusion 3.0 - CO N C LU S I O N S...............................................

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e FOREWORD This Technical Evaluation Report (TER) was prepared by Science Applications International Corporation (SAIC) under a contract with the U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Reactor Regulation for technical assistance and support of NRC operating reactor licensing actions. The technical evaluation was conducted in accordance with criteria established by the NRC.

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1.0 INTRODUCTION

l l

1.1 Purpose of Review l

l This Technical Evaluation Report (TER) documents an independent review of exemption requests from the requirements of Appendix R to 10CFR50 for various areas at Quad Cities Units 1 and 2 (Docket Nos. 50 254 and 50 265) submitted by Commonwealth Edison (the licensee). The evaluation was performed:

1.

To assess if each exemption request demonstrates an equivalent level of overall protection of plant safe shutdown capability following a disabling fire event and, 2.

To determine the bases for acceptance or denial of each exemption request.

In addition, an independent review was performed to assess the impact on previously approved exemptions, by modifications in combustible loading values submitted by the licensee.

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 prntection 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 l

recommendations regarding improvements in fire prevention and control in existing 1

facilities. The report also called for the development of specific guidance for implementing i

fire protection regulations, and for a comparison of that guidance with the fire protection program at each operating plaat.

1

The NRC developed technical guidance from the technical recommendations in the Special Resiew Group's report, and issued those guidelines as Branch Technical Position (BTP) APCSB 9.51. This guidance did not apply to plants operating at that time.

Guidance to operating plants was prosided later in Appendix A to BTP APCSB 9.51,which to the extent practicable, relies on BTP APCSB 9.51. The guidance in these documents was also published as Regulatory Guide 1.120.

By early 1980, most operating plants had implemented most of the guidelines in Appendix A. However, the fire protection program 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 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, the reactor coolant c

pump lubrication system, and alternative shutdown systems.

On February 17, 1981, the final rule 10CFR50.48 and Appendix R to 10CFR50 became effective, replacing the proposed rule. Only three of the 15 items in Appendix R were of such safety significant 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 shutdown capability (including alternative 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 than the proposed rule because Item Ill.G now 1 aides 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 alternative from 50 feet to 20 feet. In addition, the ru'e now provides an exemption procedure which can be initiated by a 2

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4 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.

In summary,Section III) is related to emergency lighting and Section III.G is related

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to fire protection features to ensure 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 Section III.G and IIIJ or an alternative fire protection configuration must be justified by a fire hazards analysis. Generally, the staff will accept an alternative fire protection configuration if:

i o

The alternative ensures that one train of equipment necessary to achieve hot i

shutdown from either the control room or emergency control stations is free of j

fire damage.

l 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).

e 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.

l o

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

I, facility safety.

1.3 Plant Specific Background By Letter dated September 30, 1987 the licensee requested exemptions from the requirements of Appendix R for ceparatio, f redundant reactor vessel pressure and level

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indicating instruments in the Unit i reactor building and separation of redundant suppression pool level Indicating instruments in the Unit 1 and Unit 2 reactor buildings.

By letter dated October 1,1987 the licensee supplemented their September 30,1987 submittal by making a request for two additional exemptions from the requirements of Appendix R. These additional exemption requests were for lack of emergency lighting for the suppression poollevelinstrumentation and the need to pull fuses to preclude spurious component operation in order to achieve stable hot shutdown.

By [[letter::05000254/LER-1987-022-04, :on 871109,intermediate Range Monitor (IRM) 14 Spiked hi-hi Resulting in Full Reactor Scram.Caused by Faulty IRM 14 Hardware.Irm 14 Will Be Investigated & Repaired|letter dated November 23,1987]] the licensee revised the October 1,1987 r,ubmittal.

In their new submittal, the licensee deleted the exemption pertaining to the separation <

By letter dated April 11, 1990 the licensee made a submittal which requested modifications in cornbustible loading definitions used in exemption requests submitted to the NRC on June 25,1986. The original exemption requests were evaluated by the staff and approved in a Safety Evaluation Report (SER) dated July 21,1988.

1.4 Review Criteria The criteria for performing the review are from the following documents:

1.

Appendix A to Branch Techreal Position (BTP) APCSB 9.51,

  • Guidelines for Fire Protection for Nuclear Power Plant Docketed Prior to July 1,1976
  • 2.

Appendix R to 10CFR50,' Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1,1979,*

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3.

Standard Review Plan, NUREG 0800, Branch Technical Position (BTP), CMEB 9.51, " Guidelines for Fire Protection for Nuclear Power Plants," Rev. 3, July 1981.

4.

Fire Protection Program for Operating Nuclear Power Plants,10CFR50.48.

4 5.

Generic Letter 8610,

  • Implementation of Fire Protection Requirements," dated April 24,1986.

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2.0 EVALUATION 2.1 Separation of Redundant Reactor Level Indicating Instrumentation 2.1.1 Exemption Requested Exemptions were requested from the technical requirements of Section III.G.2.b of Appendix R to the extent that 20 feet of horizontal space free of intervening combustibles

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and area wide suppression is not provided within the fire area containing redundant reactor vessel leve; indicating instrumentation for each unit.

2.1.2 Discussion Cables associated with redundant control room reactor levelinstrumentation (LIl 263-101,100A&B,106A&B; LRl 263113, LR 240 26) are located in the Unit 1 Reactor Building (Fire Area RB 1) and (L12 263101,100A&B,106A&B; LR2 263113, LR 240 26) in the Unit 2 Reactor Building (Fire Area RB 2). The licensee states in their submittal that in the event of a fire in either Fire Area RB 1 or RB 2, local instrumentation within that fire area would be used to monitor reactor vessel level. Local instrumentation is available on the mezzanine floor, the ground floor and the torus level for each of the respective Units. Each of these elevations constitutes a separate fire zone within the Reactor Building fire areas.

All three fire zones in question for each unit are provided with fire detection with the exception of some rooms within the zones, hianual hose stations and portable extinguishers are located throughout the ground floor and mezzanine levels and at the entrance to the torus level.

The licensee states that automatic water suppression is not appropriate for the fire zones in question due to the possible adverse affects on safety related components. The 6

licensee also states that gaseous suppression systems would not be effective due to the large volumes of the zones and therefore inability to achieve a required concentration of agent.

Combustibles consist primarily of cable insulation and account for an equivalent 2

loading of 30,000 Bru/ft' and 20,000 Btu /ft on the ground floors of Units 1 and 2 respectively and 20,000 Btu /ft on the mezzanine levels of both Units. Adminisuative 2

procedures are in place to control transient combustibles which include requiring any j

lubricating and cleardng fluids to be handled only in approved containers.

Reactor level instrumentation is available on any of five d!fferent instrument racks in Fire Areas RB 1 and RB 2. One set of instrumentation is located on the torus level, with two separate instrument racks located each on the ground floor and the mazzanine floor of each unit. Instrument lines for the levelinstrumentation are located within Fire Area RB 1 and RB 2.

2.1.3 Evaluation Fire Areas RB.1 and RB 2 are not in compliance with Section III.G.2.b of Appendix R because redundant reactor vessel level circuitry and instrumentation are located in the same fire area. In addition, automatic fire suppression is not provided.

In the event of a fire in the Reactor Buildings, Fire Areas RB 1 or RB 2, cables associated with reactor vessel level indication in the Control Room could be damaged and 4

therefere the indication lost. The licensee is relying on local instrumentation provided in the Reactor Buildings at any one of five different locations. The concern with this reliance is the ability to gain access to at least one of these locations and provide the required monitoring capability, since all locations are within the same fire area as the postulated fire.

The Reactor Buildings, however, consist of multiple elevations which have been subdivided into separate fire zones. Fire detection is provided throughout most of the fire 7

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rones containing the instrumentation of concern. It would be expected that a fire in any of the rones would be detected in its incipient stages and the Control Room alerted of the fire condition. The Control Room would then respond the plant fire brigade which could control the fire using the installed manual hose stations and fire extinguishers. Based on the combustible loading and distance between instrument racks within separate fire rones, there is reasonable assurance that a fire would be prevented from damaging all five instrument racks. There was a cancern with the spatial separation of the instrument lines corresponding to the various innrument racks. The licensee was therefore requested to provide drawings which detailed the location of the instrument racks and the instrument lines for each rack. The drawings provided by the licensee demonstrated that there was sufficient spatial separation between instrument lines to ensure that at least one level instrument and its sensing line would remain free of fire damage for any single fire in fire Areas RB 1 or RB 2.

There was also a concern with the ability of an operator to gain access to an instrument panel when there was an on going fire in the same fire area. There was particular concern with the ground floor, since an operator may be required to monitor instrumentation on the same elevation. Based on discussion with the licensee and additional information provi6td to the staff, there is reasonable assurance that an operator could gain access to, and remain at the required instrumentation to monitor reactor vessel level. This conclusion was reached based on several reasons. The low combustible loadings would limit the extent of any fire which may occur. The large volume of the fire zones would dissipate the smoke and heat from a fire, generally towards the upper elevations. And in addition, the licensee stated that level monitoring would not be required until 35 minutes after the initiation of safe shu'tdown. This would allow for fire fighting activities to be well under way.

Because of the multiple locations within the Reactor Buildings where vessellevel can be monitored and the existing separation of the levelinstruments and sensing lines, there is reasonable assurance that the existing plant fire protection features provide an equivalent 8

level of protection as required by Section lit.G.2.b of Appendix R and therefore no additional modifications are warranted.

2.1.4, Conclusions Based on the evaluation above, there is reasonable assurance that the lack of separation of redundant vessel level instrumentation and the lack of automatic fire suppression in Fire Areas RB 1 and RB.2 does not adversely affect the ability of the plant

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to achieve and maintain safe shutdown and therefore, these exemptions can be granted.

2.2 Separation of Redundant Suppression PoolI.4velIndicators 2.2.1 Exemotion Requested An exemption was requested from Section III.G.2.b of Appendix R for lack of adequate separation between redundant Suppression Pool Level Indicators for Fire Areas RB 1 and RB 2 in Units 1 and 2 respectively, in addition, detection and suppression are not prosided, i

2.2.2 Discussion Fire Areas RB 1 and RB 2 in the Unit I and Unit 2 Reactor Buildings contain the Suppression pool level sight glasses and level transmitters along with the cables that provide power and instrument cables leading to the Control Room level indicators. A fire in the Northern half of the torus level of each Unit could affect the level indicators in the Control o

Room and, therefore, the sight glass for each Unit would remain the means of monitoring suppression pool level indication.

2 The combustible loading of the torus levels is less than 10,000 Btu /ft for each Unit.

Transient combustibles are limited due to the restricted access to these levels. Cable trays 9

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on the torus level are provided with linear fire detectors. An automatic sprinkler system is provided where cable trays pass through the ceiling.

The ground floor, above the torus level, has combustible loadings of less than 30,000 Btu /ft for each unit. Smoke detection is provided throughout this elevation for both Units.

8 Manual hose stations and extinguishers are provided on this elevation for both Units.

In the event of a fire damaging Control Room suppression pool level indication, an operator would have to monitor suppression pool level us!ng the sight glass. The licensee states in their submittal that pool level monitoring would not be required until three hours into the event when RHR torus cooling is initiated.

2.2.3 Evaluation Fire Areas RB 1 and RB.2 are not in compliance with Section Ill.G.2.b of Appendix R because redundant instrumentation for monitoring suppression pool level are located in the same fire area.

However, the combustible loading in the torus level is low. Cable trays that do exist are provided with linear detection. The accumulation of transient combustibles would be minimized by the restricted access to this level. Combustible loading on the ground floor l

above is greater than that on the torus level, however it is still low. Detection is provided throughout the ground floor in addition to manual hose stations and extinguishers.

i While there is reasonable assurance based on the low combustible loading on the torus level that a fire would not damage the sight glass, there was a concern that operators would not be able to gain access due to smoke conditions. However, the licensee has indicated that pool level monitoring would not have to begin until three hours into the event. This would allow sufficient time for the fire brigade to control any fire and for smoke removal 10

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actidties to be implemented. Therefore, suppression pool monitoring capability would be available even if the control room monitoring capability was lost.

2.2.4.CondusinD 3

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Based on the evaluation above, the lack of separation of redundant suppression pool level instrumentation per the requirements of Section III.G.2.b of Appendix R, including the s

lack of automatic suppression in the torus level, would not adversely affect plant safety and therefore this exemption can be granted.

l 2.3 Lack of Emergency Lighting for Suppression Pool I.evel Instrumentation 1

2.3.1 Exemotion Reauested i

An exemption was requested from Section IIlJ of Appendix R to the extent that emergency lights are not provided for the suppression poollevel sight glasses for Unit 1 and j

Unit 2.

l 2.3.2 Discussion i

I Section 2.2 of this report provided an evaluation of the use of sight glasses to provide l

a redundant means of monitoring suppression pool level. The licensee has identified that should operators be required to use the sight glasses, they will use portable emergency lights available in the Control Room.

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2.3.3 Evaluation The licensee has indicated that procedures call for operators to be issued portable lights when they leave the Control Room to Perform manual safe shutdown actidties. Since 1

j monitoring suppression pool level is not considered requred until three hours into the 11-l

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event, the operators would have sufficient time to obtain the necessary portable lights. The installation of emergency lights for the sight glasses would not significantly increase plant safety and therefore can be considered an acceptable exemption from Appendix R.

2.3.4 Conclusion The lack of installed emergency lights for the suppression pool level sight glasses for Units 1 and 2 is considered acceptable and therefore the exemption can be granted, i

2.4 Pulling of Fuses for Hot Shutdown 2.4.1 Exemotion Requested The licensee has requested an exemption from the requirements of Appendix R to the extent that fuse pulling, which could constitute a " repair,"is required to prevent spurious equipment operation during hot shutdown.

2,4.2 Discussion r

In the event of a fire in Fire Areas TB 1(Turbine Building Northerri Zone Group) or TB Ill (Turbine Building Southern Zone Group), RHR system logic cables associated with the safe shutdown equipment could possibly be damaged by the fire. This damage could potentially result in spurious operation of safe shutdown equipment, including RHR pumps and valves, diesel generator auxiliary equipment, safety relief valves, and 4 ky breakers. In order to prevent the possibility of spurious operation, the power to the RHR logic circuits must be deenergized. For fires in other areas of the plant where this problem exists, the circuits are deenergized by tripping the breakets in the de distribution panel rooms in the Turbine Building. These rooms, however, are located in the Northera and Southern Zone J

Groups and could be inaccessible.

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d In order to deenergize the circuit for a fire in the Northern Zone Group, eight fuses located in panel 902 32 in the auxiliary electric equipment room (Fire Area SB 1) would be removed. For a fire in the Southern Zone Group, eight fuses located in panel 90132 also in the auxiliary electric equipment room would be pulNd.

All of the fuses in questica are in contro\\ circuits and are rated 15 amperes or less.

The licensee states that actualload currents are considerably less and therefore no pettoraal safety equipment is need for their removal. The lleensee also states that the operators have been trained at pulling similar fuses for routine testing and maintenance operations.

2.4.3 Evaluation Appendix R requires the tibility to achieve hot shutdown without performing repairs.

Actisities such as pulling fuses can be considered repairs and therefore are not in compliance with Appendix R.

l However, the staff has found pulling fuses to prevent spurious component operation, to be an acceptable exemption from Appe" dix R when the fuses can be removed safely an 1 can be accomplished easily and without eric r. All of the fuses in question are low voltage and would present no personnel safety concern. All the fuses required to be pulle.d are located in either one of two panels both of which are located in the Auxiliary Electric Equipment Room in Fire Area SB 1. Therefore this activity can be accomplished easily and quickly. Also, fuse pulling to prevent spurious componen1 operation would only be used for

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two fire scenarios in the plant and is not routinely relied upon for achieving post fire late shutdown. Therefore, the use of fuse pulling under the limited conditions outlined in the licensee's submittal is considered acceptable.

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I 2.4.4 Concluslop Dased on informa(it n prov;ded in the licensee's October 1,1987 submStal and in the evaluation above, the use of fuse pulling to achieve hot shutdown is considated acceptable and the exctnption can be grti?cd.

2.5 Modification in Combustible (onding Calculations 2.5.1 Discuss',

By letter Uted April 11,1990 the licensee reques.ted a modification to exe. mph requests previously approved :p the NRC by SER dated July 21,1988. The licensee las requwed that combstible.oading eiues identified in the original request for exemption submittal dated June 25,1986 be mokied.

p 2.5.1 Aalua110D This request is a result o! an internal quality assurance audit which identified that some of the combustible Imdireg values used in the request for exemption had been exceeded. The lleedte perrorrNI r.u investigation to determir;e why the original values had been exceeded s.nd made several coi ch:slons; cor bustible loadings were recalculated due to revisions in the heat of combustiv.' value. dereby changing the totals; approved combustible load limits were exceeded de 13 increases in the fixed combustibles; and approved combucible load innits were execcocd due to the introduction of transient combustibles. The lleensee concluded that the valt ?.s identified in the original exemption request were too 12strictive and dkJ not allow for nce tal plant operation while still ensuring i

adequate fire safety. The licensee's April 11,1990 s ibmittal is requesting a modification to the combustible had limits defined h, she Juae 25, 1986 submhtal These new combustible loadings were reviewed with consideration to conclusions made X the staff in evaluating the eremption requests. The original loadings which the licensee pm, oses to 14 i

2 modify are all relatively low,less than 30,000 Stu/ft, with four of the five figures less than 2500 Btu /ft. The licensee proposed increases which still maintain the loadings less than 2

2 2

40,000 Btu /ft with four of the five new values less than 10,000 Btu /ft, Based on review of the original exemption requests, these new values would not present any additional concern other than those rceviously addressed by the staff, and therefore would not affect previous NRC approval. Therefore the modification of the combustible loadings as stated in the licensee's Ap.il 11,1990 submittal are acceptable 2,5.3 Conclusion Based on information provided ir. the licensee's April 11,1990 submittal and in the evaluation above, the reqc:ns for exemptions from Appendix R approved in the July 21, 1988 SER remain valid.

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3.0 CONCLUSION

S Based on the evaluations contained in this report, of requests for exemptions from the requirements of Appendix R, the following exemptions have been granted:

1.

Lack of separation for redundant vessel level indication and automatic suppression throughout Fire Areas RB 1 and RB 2.

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2.

1.ack of separation of suppression pool level indication and automatic suppression throughout Fire Areas RB 1 and RB 2, 3.

Lack of fixed emergency lights for suppression pool sight glasses.

4.

Use of fuse pulling to preclude spurious component operation during hot

shutdown, i

in addition, the modification of combustible loading limits in previously approved exemptions requests was found to be acceptable.

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