ML20042E449

Forwards Request for Rev to Previous NRC Exemption Approval on 860625 Re Combustible Load Values

ML20042E449
Person / Time
Site:	Quad Cities
Issue date:	04/11/1990
From:	Stols R COMMONWEALTH EDISON CO.
To:	Murley T Office of Nuclear Reactor Regulation
References
NUDOCS 9004230054
Download: ML20042E449 (14)

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X}_x1400 Opus Place C:mm:nwealth Edis:n Downers Grove, Illinois 60515 -

l April-11, 1990: ,

Dr. Thomas E. Murley, Director.

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission y Washington, DC 20555- -

Subject:

. Quad Cities. Units 1 and 2 -

Request forl Revision to Appendix R Exemption Approval NRC Docket 50-254/50  :

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Reference:

-(a) Letter frem J.R. Wojnarowski to H.R. Denton dated June 25, 1986 ,

s (b) Letter from T. Ross to H. Bliss dated July. 21, 1988.

Dr. Murley:

Reference (a) transmitted a request for approval of exemptions to Appendix R requirements. .The exemption requests were presented in sections for clarity of review. Reference (b) transmitted the Safety Evaluation' Report (SER) for granting the' exemption request.-

As a result,of a Quality Assurance Audit and the initiation'of'a computer tracking program for combustible materials at Quad Cities, Commonwealth Edison identified that insufficient' flexibility is contained in-the combustible loading limits subinitted in reference (a) 1 Additional details are contained in Attachment A. Commonwealth Edison, therefore, is requesting revision to the combustible load limits. contained in reference (a).

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Justification for these revised limits is contained in Attachment B.

If there are any further questions or comments, please direct them to this office.

Very truly yours, Rita'Stols I

, Nuclear Licensing Administrator I i

cc: ~L.. 01shan, NRR Project Manager ll D. Notley, NRR A. Bert Davis, Regional Administrator, NRC '

Senior Resident Inspector, Quad Cities

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ATIAUIEElfLA Backgrsund On March 21, 1990, a Quality Assurance Auditor identified that the combustible load in a Fire Zone had exceeded the value contained in an Appendix R exemptien request. An investigation of all fire zones was initiated to identify areas in which Appendix R exemption limits were exceeded. Compensatory' measures, in the form of fire; watches, were immediately instituted for Fire Zones where values were exceeded.

Commonwealth Edison is reviewing.this event to-identify the root cause for  !

exceeding combustible load values and that the values were not properly t controlled.

The reasons why Appendix R exemption combustible loadings were exceeded fall into three categories:

l 1. Combustible loads were recalculated.due to revisions in the heat of combustion values for various combustibles. No change in physical combustible loads was made.

2. Approved combustible load limits were exceeded due to increasec in the fixed combustibles (e.g. Anti-contamination clothing hamper) in the area. ,

-3. Approved combustible load limits were exceeded due to the introduction of transient combustibles in the area.

These categories were discussed with NRR-Staff and the following conclusions were achieved:

1. No revision to the exemption approval-or. compensatory measures are required for those fire zones in which the limit was exceeded soleiv due to revised calculations performed to accommodate revisions to the- '

heat of combustion values.

2. If the Safety Evaluation Report (SER) provides a limit associated ,

with the exemption request approval-(e.g.' fire severity does not

• exceed 23 minutes for any zone), the individual zone may. exceed the submitted combustible loading up to the limit defined in the SER. A technical review must be performed for the individual-zone to demonstrate the acceptability for adopting-the higher limit contained in the SER. The-justification is not. required to be submitted to the NRC; however, the justification must be maintained in.an'auditable file. Compensatory measures can be removed.

3. Request for exemption approval revision is required for areas for which the above discussion does not apply. Attachment 'B' contains the justification for the revised combustible-loading for such areas.

Commonwealth Edison is currently reviewing the limits defined in the '

Appendix R exemption requests to assure sufficient flexibility exists in the ,

' defined exemption values to accomodate future, expected, operating and maintenance activities. Following this review, additional requests for exemption revision will be submitted as neede6.

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.i ATTACMENT B l 4

' REQUEST FOR REVISION TO PREVIOUS s

NRC EXEMPTION APPROVAL i

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13.0 AEEENDIX R EXEMEIION EQUEST TO REVISE COMBUSTIBLE LOAD VALUES CONTAIED

.lN_AEERQVED EXEMPTION.P1 QUESTS.

Per the provisions of 10 CFR 50.12, Commonwealth Edison Company (CECO) had requested exemption from the requirements of Sections III.G.2. III.G.3 and III.L of Appendix R to 10 CFR 50. In justifying exemptions'from the requirements of these sections, an evaluation was performed to demonstrate i that adequate fire protection measures exist for the fire zones that do not '

meet the Appendix R: requirements and a combustible load limit was established to demonstrate that the amount of combustible materials in these fire zones was lov.

A review of these combustible load values has shown that sufficient flexibility is not provided to perform routine operation and maintenance activities, particularly during an outage. Therefore, CECO is submitting this request to revise exemptions previously approved in the Safety Evaluation-Report (SER) dated July 21, 1988, to reflect higher combustible load values.

-Table 13.0-1 lists each fire zone, the original combustible load _value and the new combustible load value.

To determine the new combustible load, a reev91uation of each fire zone' '

was performed based on the fire barriers in the fire zone, the type of combustibles, and sound fire protection-judgment. The following conservative '!

approach was used to establish the new limits: i

1. The evaluation was performed assuming-outage activities when transient combustible loads should be at their highest point.

2. A fire severity limit was set for the fire zone based on whether fire  !

detection or automatic fire suppression existed in the zone. For fire l

zones without fire detection or suppression, a fire severity limit of 15 minutes was established and for those with fire-detection or suppression, a 30 minute limit was established. Using these fire. (

severity limits, the new combustible load limit was derived. These limits were conservatively set well below the NFPA test data for fire  ;

severity by assuming the combustibles are flammable liquids.

3. For areas with extremely low limits, the existing values-for each fire ,

zone were' increased to the expected combustible loadings required and '

reviewed against the individual characteristics of each' fire zone. For most of the fire zones, this proved to be an adequate solution since  ;

original limits were extremely low to begin with and the increase on  ;

fire severity was negligible.

4. The additional loading would not increase the probability of' initiating- ,

a fire since ignition sources, if any, in the fire zones are not being  !

changed.

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. -1 The justification for increasing the combustible load value for each of the previously approved exemptions are presented in the-following sections..

Affected SECIl0H ~ JUSTIFICATION FOR fitt_ZQDB -

13.1 Lack of complete 3-hour fire barrier 8.2.10 between Southern and Central Zone Groups.- .8.2.1.A.

14.1.1-11.1.1.B.

13.2 Lack of complete .3-hour barrier between 8.2.1.A Northern and Southern Zone Groups. 8.2.7.D 11.1.1.B 13.3 Lack of complete suppression and detection- 8.2.7.D for enclosure of cable in fire barrier having a 1-hour rating.

13.4 Lack of complete 3-hour fire barrier 11.1.1.B between Fire Zone-11.1.1.B and Southern 8.2.1.A Zone Group.

-i 13.5 Lack of complete _3-hour fire barrier 8.2.7.D-between equivalent Fire Area 8.2.8.D and Northern Zone Group.

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- TABIX 13.0-l' .,

Sumneary For Exemption Request ~ Revision .

Fire Zone Approved' Combustible Exemption SER~ ..

Requested Load Limit (BTU /ft2 ) Request .Section- Load Value (BTU /ft2) 8.2.10 2500 5.2 9.0 '5000 14.1.1 1000 5.2 9.0 5000 8.2.1.A 1000 5.2- 9.0 2000

- 5.3 10.0 5.9 8.2.7.D 30000 .5.3 10.0 40000

.5.7 6.0 5.10 14.0-

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11.1.1.B 2500 5.2 9.0 10000 5.3 -10.0 5.9 13.0-

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__ __=  :-_ .. _ _ - - _ - - . _ = _ - _ _ - . . _ _ _ . _

f 13.1 LACK OF COMPLETE 3-HOUR FIRE _ BARRIER BE'IVEEN THE SOUTHERN AND CENTRAL.

-ZONE CROUIS. .

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-The following exemption request contained in-the June. 25, 1986 submittal is affected by the revision to the combustible loadings in Fire Zones 8.2.10.

14.1.1. 8.2.1.A and 11.1.1.B: i Section 5.2: Lack of a complete 3-hour fire barrier between the Southern and Central Zone Groups t'

Fire Zone 8.2.10 (Central- Zone Group) and Fire Zone 14.1.1 (Southern '

Zone Group) share a boundary on the-626'-6" elevation, where the fire zones are separated by a substantial reinforced concrete shield wall that is not ,

specifically fire rated. Personnel access between the zone groups is through substantial. unlabeled, metal doors. There are no safe shutdown cables or  ;

equipment in either of the fire zones. The principle concern in either the Central or Southern Zone Group is- that a fire could develop, spread to an adjacent zone group and damcge the necessary safe shutdown system components. (

Fire Zone 8.2.1.A and 11.1.1.B are located.in-the Southern Zone Group.

These fire zones do not share a common boundary with any fire zone-contained' in the Central Zone Group, however, are discussed in the NRC's SER.

The NRC subsequently granted the proposed exemption. The' basis for the Staff's approval of the exemption request contained in the. July 21, 1988 Safety Evaluation Report (SER) included:

1. The two fire zones are separated by a reinforced concrete shield wall with metal, personnel access. doors that are locked shut.

2. Fire zones 8.2.10 and 14.1.1 contain no safe shutdown cables; 3.

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The fire load is low and therefore a postulated fire in either area is expected to develop slowly and remain small. The heat would dissipate to surrounding areas without spreading to an adjacent zone group.

t The SER concluded since a fire in either the Central or Southern Zone Group would not damage an alternative safe shutdown path located out of the zone groups and/or spread to the adjacent zone group, the complete.3-hour fire rated barrier would not significantly upgrade the level of fire protection. i Since the submittal.of the exemption request, no safe shutdown systems or components have been added and the physical configuration of the fire zones remains unchanged; however, the need to increase the allowable combustible loading has been identified.

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• Commonwealth Edison, therefore, requests that the allowable comb'ustible loading be increased as follows:

ApptovedLimgt Enqunated Limit Zone 8.2.10 2500 BTU /ft 5000 BTU /ft Zone 14.1.1 1000 BTU /ft2 '2000 BTU /ft Zone 8.2.1.A 1000 BTU /ft2 2000 BTU /ft2-Zone 11.1.1.B 2500 BTU /ft2 10,000. BTU /ft2 The increased loading meets the.basisoof the exemption approval in that the fire load remains low and well within the capability of the concrete shield wall to contain the fire. -(NFPA Handbook defines low combustible loading to be less than 100,000 BTU /ft .) 2 Neither Fire Zone 8.2.10 nor 14.1.1 contain safe shutdown equipment. The combination of the shield walls-and the low combustible loading continues to assure that a fire cannot 1 propagate between the Central and Southern Zone Groups at this elevation and, therefore, the revision to the exemption should be granted. J i

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13.2 LACK OF COMPLEIE_3-J10UR BARRIER BE'DfEEN NORTilERN AND SOUTHEBN ZONE GRQUfE.

The following exemption request contained in the June 25, 1986 submittal is affected by the revision to the combustible loadings in Fire Zone 8.2.1.A.

E1LD and 11.1.1.B Section 5.3 Lack of complete 3-hour barriers between Northern and' Southern Zone Groups. -

Fire Zones 8.2.1.A and 11.1.1.B are located in the Southern Zone Group.

Fire Zones S.2.1.A and 11.1.1.B do not share a common boundary with the Northern Zone Group and Fire Zone 8.2.7.D is located -in the Northern Zone Group and does not share a common boundary with the Southern Group. These Fire Zones, however, are discussed in the July. 21, 1988 SER for this exemption request. The Northern and Southern Zone Groups share a common boundary- only.

along positions of the Unit 2 Cable tunnel (Fire Zone 8.2.5) and in the radwaste pipe tunnel. The principle concern for the lack of a 3-hour barrier is that a fire in either Zone Group could develop and spread to an adjacent; zone group and damage necessary cable or equipment necessary for safe shutdown.

The Staff's basis for the approval of the exemption request contained in the July 21, 1988 SER primarily focused on the Northern and Southern Zone ,

group interface configuration and' existing fire protection systems in the  !

interface zones. Since the Staff's SER also references.the non-interface areas, Commonwealth Edison-is formally requesting a revision to the exemption approval to reflect increased combustible loadings as follows:

i' APPIneLLimp Resuaaleiligli Fire Zone 8.2.1.A 1000 BTU /ft 2000 BTU /ftz 8.2.7.D 30000 BTU /ft2 40000 BTU /ft2.

11.1.1.B 2500 BTU /ft2 ~ 10000 BTU /ft2 j i i

The increased loading meets the basis for the exemption approval since  !

loading remains low. In addition, none of these zones share a.-common boundary 1 with-the Northern or Southern Zone Group; therefore, the spread of a fire ]

originating in the Fire Zones to the other Zone Group is limited. The  !

increased loading should, therefore, be approved. I i

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13.3 JUSTIFICATION FOR LACK OF COMPLETE SUPPRESjl0N AND DIIECTION FOR ENCLOSURE OE_C&BLE IN A ElRE RARRIER HAVING A 1-HOUR RATING.

i The following exemptien request contained in the June 25, 1986 submittal e is affected by the revision to the combustible loadings in Fire Zone 8.2.7.Dt i Section 5.7 Justification for Lack of Complete Suppression and Detection l for Enclosure of Cable in a Fire Barrier having a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Rating The turbine building contains certain cables which are required to be  !

wrapped in a 1-hour fire barrier because they are routed through fire zones  !

which have alternative shutdown methods that take credit for equipment fed by the cable running through the zone. The 4KV bus duct to switchgear 23-1 is wrapped in a 1-hour barrier where it passes through the Fire Zone 8.2.7.D of the Northern Zone Group.

• The Northern Zone Group uses alternate shutdown path C for hot shutdown. l Shutdown Path C uses equipment powered by switchgear 23-1. This bus duct is ,

protected with complete automatic suppression where it passes through Fire  !

Zone 8.2.7.D and partial detection is provided. There are also hose reels and i portable extinguishers in the fire zone which could be used by the fire brigade to fight the fire. The principle concerm with a fire in the fire zone having a bus duct penetration is that a fire could spread through the bus duct penetration.

The NRC subsequently approved the exemption request. The following basis for the Staff's approval is contained in the July 21, 1988 SER:

1. The fire loading is low and a fire of major proportions is not expected to occur.

2. Fire Zenes 8.2.7.D has automatic sprinkler protection, t

3. The bus duct metal enclosure would be resistant to small fires and would not likely fail inr up to a ene hour time period. ,

t The SER concluded that the installation of a 3-hour rated bus duct '

penetration would not significantly increase the level of fire protection in this fire r.one. .

Since the submittal of the exemption requeat, no safe shutdown equipment  ;

or componente have been added and the physical configuration of the fire zone 3 remains unchanged; however, the need to increase the allowable combustible loading has been identified. Commonwealth Edison, therefore, requests that the allowable combustible loading in Fire Zone 8.2.7.D be increused from 30,000 to 40,000 BTU /ft ,2 The increased loading meets the basis of the exemption approval in that '

the combustible loading remains low and well within the capability of the bus  !'

duct to withstand the postulated fire. The combination of complete automatic suppression and I hour cable wrap provides a level of protection to switchgear 23-1 that is equivalent to that prescribed in Appendix R Section III.G.2.

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s 13.4 ElRE EARRIER EllWEEN FIRE ZONE 11.1.1.B AND SOUTHERN ZONE CAQUE.

The following exemption request contained in the June 25, 1986 submittal i is affected by the revision to the combustible loadings in Fire Zone 11.1.1 3  ;

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Section 5.9 Lack of complete 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire barrier between Fire Zone 11.1.1.B and Southern Zone Group.

Fire Zone 11.1.1.B contains one Division I and one Division II Residual Heat Removal (RRR) service water pump, the swing (1/2) diesel generator [

cooling water pump and their auxiliaries. The floor, ceiling and all walle  ;

are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barriers. The east wall contains a nonlabeled.

• watertight door that opens to Fire Zone 8.2.1.A of the Southern Zone Group.

Fire Zone 8.2.1.A contains the main and reserve power feeds to the swing- '

diesel generator cooling water pump. The reserve feed is protected with a 1-hour rated fire wrap. Fire protection systems contained in these areas include a complete fire detection and suppression system in Zone 11.1.1.B and  ;

a complete automatic wet pipe sprinkler system in Fire Zone 8.2.1.A. The r principal fire protection concern for these fire zones is that a fire could start in either fire zone and spread to the unaf fected fire zone through a nonrated metal watertight door.

The NRC subsequently granted the proposed exemption. The basis for the '

Staff's approval of the exemption request is contained in the July 21, 1988 SER and can be summarized as follows:

1. The fire load in either zone is negligible.

2. Both zones have automatic fire suppression systems.

3. The watertight deor 29 of substantial steel construction and sufficient to withstanc any expected fire in these zone.

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4. In the event of fire damage to safe shutdown components in either zone, an alternate safe shutdown path is available, independent of j these fire zones.

l The SER concluded that upgrading the exiating watertight door to a 3-hour fire rating does not significantly increase the level of fire protection. <

Since the submittal of the exemption request, no safe shutdown systems or l

components have been added and the physical configuration of the fire zones remain unchanged; however, the need to increase the allowable combustible

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loading has been identified.

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Commonwealth Edison, therefore, requests that the allowable combustible loadings be increased as follows:

Regues.ted Zone 11.1.1.B Approndlingt 2500 BTU /Ft 10000 BTU /ftgiali Zone 8.2.1.A 1000 B1V/ft2 2000 BTU /ft2 The increased loading meets the basis of the exemption request approval in that the fire loading remains low and well within the capability of the watertight door to contain the fire. Fire Zone 11.1.1.B has complete detection and fixed water suppression and Fire Zone 8.2.1.A has complete water suppression. The level of protection _provided by the existing fire protection features ensures that damage from a fire in Fire Zone 11.1.1.B would be limited in duration and intensity and would not adversely impact the capability to shut down the plant. The revision to the exemption approval is therefore warranted.

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13.5 1AtrJIlotitLETEl-110VR BARRIERJElyEEN EOUIVALENLIlRE AREA JAAD ANILKORIKEAli30NEJtt0Ul'.

D e following exemption request contained in the June 25, 1986 submittal is aftweted by the revision to the combustible loadings in Fire Zog 1 L l J t Section 5.10 1.ack of complete 3 heur barrier between equivalent Fire Area 8.2.8.D and Northern Zone Group i Northern Zone Group Fire Zone 8.2.7.D is located directly below equivalent Flte Area 8.2.8.D. The floor of equivalent Fire Area 8.2.8.D is not fire rated and separates the fire zone from the equivalent fire area. Fire Zone 8.2.7.D has a floor area of approximately 6100 ft2 and beiling height of l approximately 24 feet. Fire Zone 8.2.7.D is protected by an automatic vet pipe sprinkler throughout, except over the low pressure heaters and in the corridor along row C. Separate detection is provided only around cable risers in the high pressure heater bay. The area directly below equivalent Fire Aron 8.2.8.D is protected by automatic suppression and partially covered by detection. The principle concern is that a fire could develap in the Northern Zone Group (Fire Zone 8.2.7.D) and spread to the turbine building operating floor (equivalent Fire Area 8.2.8.D) and vice versa.

The NRC subsequently approved the request for exemption in a SER dated July 21,1988 from the requirements of Appendix R Section 111.G.2.a based on the following:

1. Hazards located below the operating floor are contained in reservoirs and are protected with automatic fire detection and fire suppression systems. The expected Iire would be detected early and controlled / extinguished by the fire suppression systems.

2. The areas are open and accessible. to the fire brigades.

The SER concluded that the provisions of a complete 3-hour itre rated barrier between c.e subject fire zones would not significantly upgrade the level of fire protection.

Since the submittal of the exemption request, no safe shutdown equipment or components have been added and the physical configuration of the fire zones remains unchanged; however, the need to increase the allowable combustible loadings has been identified.

Connonwealth Edison, therefore, requests that the fire loading for Fire Zone 8.2.7.D be increased from 30,000 BTU /ft2 to 40,000 BTU /ft2 . The increase in the combustible loading does not impact the basis of the exemption request approval. The low combustible loadirg coupled with the existence of .j automatic suppression in the area beneath equivalent Fire Area 8.2.8.D l' provides a high level of assurance that a fire in this zone would not spread to the equivalent fire area.

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