ML20136F338

Informs of Discovery of Two Instances Where Electrical Feeds Used in Shutdown Scheme Passed Through Fire Zone During Plant Mod Associated W/Installing Alternate Shutdown Sys. Corrective Actions Will Be Completed Prior to Startup

ML20136F338
Person / Time
Site:	Fermi
Issue date:	01/03/1986
From:	Jens W DETROIT EDISON CO.
To:	Adensam E Office of Nuclear Reactor Regulation
References
VP-85-0221, VP-85-221, NUDOCS 8601070347
Download: ML20136F338 (4)

Text

Werne na Nuclear Operatore Detroit r.

E*

(N>N41["#8" 6400 North 0000 Highway Nucleat Operations January 3, 1986 VP-85-0221 Director of Nuclear Reactor Regulation Ms. Elinor G. Adensam, Chief Licensing Branch No. 1 Division of Licensing U.

S.

Nuclear Regulatory Commission Washington, D. C.

20555

Reference:

1)

Fermi 2 NRC Docket No. 50-341 NRC. License No. NPF-43 2)

Detroit Edison to NRC Letter, " Design of Alternative Shutdown Approach", EF2-72001, October 22, 1984 3)

Detroit Edison to NRC Letter, " Submittal of Deviations from Staff Interpretations of Fire Protection Features in 10CFR50, Appendix R and Justification", EF2-72717, August 3, 1984 4)

Detroit Edison to NRC Letter, " Alternative Shutdown in the Control. Center Complex",

EF2-72718, August 16, 1984

Subject:

Alternste Shutdown System During the recent plant modifications associated with installing the Alternative Shutdown panel, Detroit Edison discovered two instances where electrical feeds used in the shutdown scheme passed through a fire zone that the alternative shutdown system was installed to protect.

This arrangement is in conflict with statements made in Reference 2 that cabling would not be routed through such fire zones.

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Ms.

E.

G. Adensam J a n u a r y 3,. 1 9 8 6 VP-85-0221 Page 2 One of the electrical feeds in question supplies power to DC Distribution Cabinet 2PB-2.

This cabinet in turn supplies power'to the Safety Relief Valve (SRV) F013G solenoid enabling control of_the SRV from the shutdown panel. -The electrical feed originates at the Division II

. battery and is then routed downward into fire zone eight (AB-8) at the 631' elevation of the Auxiliary Building.

- From there.it passes upward to the 2PB-2 Distribution Cabinet.

- An appr'oved one-hour fire barrier will be installed on this cable in-fire zone AB-8.

As indicated in FSAR Section 9B.4.2.9, fire zone AB-8'is protected by an automatic CO 2

' suppression ~ system and fire detectors.

Section III.G.2.c of 10 CFR 50, Appendix R ~ indicates that acceptable.

protection is provided by the combination of a one-hour fire barrier, automatic suppression and detection.

This is further clarified in Generic Letter 85-01.

The other electrical feed in question is a 4160V Calvert Bus Power System which passes through fire zone AB-2 also in the Auxiliary Building.

This bus supplies power to the switchgear which feeds the Standby Feedwater System used in.

the alternate shutdown scheme.

1 Rather than utilizing the alternate shutdown system, Detroit Edison has chosen to meet the provisions of 10CFR50 Appendix R Section III.G.2 for this fire zone.

This approach eliminates the dependence on the Calvert Bus by protecting ~one division of shutdown ~ systems'from fire damage and was the initial approach for fire zone AB-2 outlined in Reference 3.

Reference 3 requested a deviation i

from Section III.G.2 because horizontal cable trays (intervening combustibles) were present between the shutdown divisions.

In that letter, Edison committed to install.12 fire stops in these cable trays to prevent the spread of a fire from one division to the other.

The NRC staff approved this deviation in Safety Evaluation Report Supplement 5 (SSER5), concluding the deviation provided a level of fire protection safety equivalent to the technical requirements of Section III.G.

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January I,.Ad188 dam Ms.

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G VP-85-0221 Page 3 When Edison later committed to install alternate shutdown capability (Reference 3), a decision was made to utilize that capability to meet the provisions of Appendix R for other fire zenes as well.

The NRC staff also approved this approach in SSERS.

In order to ensure that one train'of systems necessary to achieve and maintain hot shutdown-is free of fire damage in fire zone AB-2, Detroit Edison is relying on provisions in Section III.G.2 and III.G.3 of Appendix R.

As indicated in FSAR 9B.4.2.3, automatic sprinkler suppresssion and fire

' detection is provided in this zone.

Where redundant shutdown trains are not separated by_more than 20 feet, a one-hour fire wrap is being applied to one division with the exception of three cable trays (2K-017, 2K-029, and 2K-030)..Because of their orientation in a congested area, 4

it is not feasible to wrap these trays.

These trays contain several indication and control circuits needed to achieve safe shutdown (reactor pressure, reactor water level, torus water level, torus temperature and temperature control of the EECW Heat Exchanger inlet valve).

However, the indication functions are_ independently available on the alternate shutdown panel and in the event of a fire in zone AB-2, the EECW Heat Exchanger inlet valve will be manually bypassed or opened locally to ensure EESW flow.

Therefore, the provisions of III.G.3 are met for the three cable trays and protection is not required.

The_ procedures governing shutdown in the event of a fire in zone AB-2 will be modified to reflect the need to obtain the aforementioned indications at the alternate shutdown panel and to bypass or open the EECW heat exhanger inlet valve locally.

These actions will be completed prior to startup from the current outage and are believed to achieve compliance with the provisions of Appendix R as authorized by the staff in SSER5.

These changes modify the fire protection program but do not decrease the level of fire protection from that described in the Final Safety Analysis Report through Amendment 60 and approved in the SER through Supplement No.

5.

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Ms. Elinor G. Adensam January 3, 1986

~ VP-85-0221 PAGE 4 These changes do not result in a failure to complete the fire protection program approved by the Commission prior to license issuance nor do they involve an unreviewed safety question.

Hence, they may be made without prior approval of the Commission as allowed by License Condition 2.C.(9)(c).

Should you have any questions regarding this matter, please call Mr. A.

E. Wegele (313) 586-4210.

Sincerely, f

MV YM L

cc:

Mr.

P. M.

Byron Mr. M.D.

Lynch a

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