IR 05000341/1985050

Safety Evaluation Re Proposed Fire Protection Mod to Independent Alternative Safe Shutdown Capability to Satisfy Open Items in Insp 50-341/85-50

ML20212M524
Person / Time
Site:	Fermi
Issue date:	01/16/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20212M478	List: IR 05000341/1985050 ML20212M475
References
NUDOCS 8701300150
Download: ML20212M524 (4)

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Enclosura

[er aeg)og UNITED STATES g g NUCLEAR REGULATORY COMMISSION 3 :p WASHINGTON, D. C. 20555

\~.../ SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RilATIVE TO PROPOSFO FIRE PPOTECTION MODIFICATION TO INDEPENDENT ALTERNATIVE SAFE SHUTDOWN CAPAPILITY TO SATISFY OPEN ITFMS IN REGION III RFPORT OF SPECIAL INSPECTTON (REPORT NO. 50-341/R5050 (DRS)) LICENSE NO. NPF-43 DFTROIT EDIS0N COMPANY FERMI-2 DOCKET NO. 50-341 1.0 INTRODUCTION By letter dated October 22. 1984, the licensee made certain commitments to the NRC regardino installation of an independent alternative safe shutdown syste Later, the licensee identified three electrical cable feeds used in the independent alternative shutdown system that are routed through the fire areas of concern for which the shutdown system is prnvided. A fire in these areas could disable both the normal shutdown systems and the independent alternative shutdown system. By letter dated January 3, 1986, the licensee proposed a different solution for each of the three electrical cable feeds. In one case they proposed installing a one-hour fire barrier around the entire length of the alternative shutdown system cables where they pass through the fire area of concer In another case the licensee chose to protect the cabling for one of the redundant safe shutdown trains and not rely on the independent alternative safe shutdown syste In the third instance, the electrical cable feeds are in cable trays in a congested area which makes it unfeasible to provide a one-hour fire barrier wrap around the trays. The licensee now contends it is not necessary to provide the fire barrier wraps proposed in their January 3, 1986 letter for these trays. Although these trays contain several indication and control circuits needed for safe shutdown, the licensee now states that the indication functions are independently available elsewhere and one of the control functions can be accomplished manuall .0 EVAtVATION Electrical feed cable No. R.I. 005 ?P supplies power to DC distribution cabinet No. 2PB-7. This cabinet then supplies power to the safety relief valve (SRV) No F013G solenoid enabling contro1 of the SRV from the shutdown panel. This cable No. R.I. 005 2P originates at the Division II battery and is then routed down into Fire Zone 8, (the fire zone of concern for which this part of the alternative safe shutdown system was installed at the 631 ft, elevation in the Auxiliary Building. After passing through Fire 7one 8, the cable passes upward to the 2PD-2 distribution cabinet. The licensee has installed a 3M-brand one-hour fire barrier wrap on this cable throughout Fire Zone 8. In addition, Fire Zone 8 is protected by automatic fire detectors and 07013001DO DR 070116 ADOCK 05000341 PDR

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-2-an automatic carbon dioxide fire suppression system. This combination of automatic fire detection and automatic fire suppression in con,iunction with one-hour fire barrier wrap conforms to the guidelines of the Standard Review Plan, Branch Technical Position 9.5-1 and is an acceptable method of fire protection for this electrical feed cable No. R.I. 005 2P. Therefore, Region III open item 341/85050-03 (6.g.(1) in Inspection Peport dated January 3, 1986)

is satisfie The other two electrical cable feeds in question are routed through Fire Zone AB-2. One of these, known as the Calvert Bus, is a 4160 volt power feed for the independent auxiliary safe shutdown system. The other involves three cable trays (2K-017, 2K-029 and 2K-030) which contain cables for indication and control circuits needed for safe shutdown. The licensee originally proposed (letter No. EF2-72717, dated August 3, 19841 to meet the guidelines of the Standard Review Plan, Franch Technical Position 9.5-1 by wrapping all of the divisional cables in Fire Zone AB- Because of difficulties encountered in wrapping all of the cables, the licensee later proposed to meet the fire protection guidelines by satisfying the technical requirements of Section III.L. of Appendix R to 10 CFR 50 and provide an alternative shutdown capability that was independent of Fire Zone AB-2. The licensee encountered difficulties attempting to instell alternative safe shutdown capability that was independent of Fire Zone AB-2. They have since reevaluated the function of the Calvert Pus and cable trays 2K-017, 2K-024 and 2K-030 and available alternative means of providing those functions. The licensee has concluded that these cable feeds are not essential for safe shutdown, given a fire in Fire Zone AB- Each is considered separately, as follow The Calvert Bus originates at the Division I Switchgear Room Buses and is routed through the cable area at the 603.5 ft. level of the auxiliary building (FireZoneAB-2,oneofthefirezonesofconcern)andontotheRadwaste Switchgear Room Puses. This Calvert Bus supplies power to the Standby Feedwater System which is part of the independent alternative safe shutdown syste ByletterdatedJanuary3,1986(letterNo.VP-85-0221), the licensee again changed their approach to fire protection in Fire Zone AB-2. They returned to their original approach of August 3,1984, and comitted to satisfy the technical requirements of Section ITT.G.2 of Appendix R to 10 CFR 50 in Fire Zone AB-2 by protecting one division of safe shutdown cables and eliminating dependence on the Calvert Bus in this area. The zone was already protected by automatic fire detection and automatic fire suppression. Additional protection that is provided for one divi: ion of safe shutdown cabling in the zone consists of a coabination of one-hour rated wraps, spatial separation and fire stoss installed in horizontal cable trays constituting intervening combustibles located within the 20-foot space between unprotected cable trays of redundant divisions of safe shutdown cables. This combination of (1)

automatic fire detection and automatic fire suppression, (2) one-hour fire rated wraps around trays of one division of safe shutdown cables, (3) 20-feet of spatial separation that is free of intervening combustibles between unpiotected trays of redundant divisions of safe shutdown cables, and (4) fire

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-3-stops installed on horizontal cable trays that are located in the 20-foot clear space between redundant divisions of safe shutdown cables, constitutes an acceptable method of fire protection for the function of the Calvert Bu Therefore, Region III open item 341/85050-04(6.g.(2)inInspectionReport dated January 3, 1986) is satisfie Cable trays 2K-017, 2K-029 a'nd 2K-030 contain indication and control circuits for reactor pressure, reactor water level, torus water level, torus temperature, and temperature control of the EECW Heat Exchanger inlet valv Since all of the above indication functions (reactor pressure and water level and torus temperature and water level) are available independent of Fire 7one AB-2 in the control room or at the dedicated (3L) panel, these cables are not required for safe shutdown and are not required to be protected. With respect to the EECW Heat Exchanger inlet valve, the licensee has revised their procedures to require an operator to manually disable the control to the Division II Heat Exchanger Temperature Control Valve so that the valve fails open (safe) in the event of fire in Fire Zone AR-2. This change in procedure and the independent availability of indication functicos at the dedicated (3Li panel and in the control room, along with the existing automatic fire detection and automatic fire suppression in Fire Zone AR-2 constitutes an acceptable method of fire protection for the cables contained in cable trays 2K-017, 2K-029 and 2K-030. Therefore, Region III open item 341/P5050-05 (6.g.(3) in Inspection Report dated .1anuary 3, 1986) is satisfie .0 CONCLUSIONS Based upon the above evaluation, we ccnclude that Pegion III open item 341/85050-03 (6.g.(1) in Inspection Report dated .1anuary 3.1 986), pertaining to protection of electrical feed cable No. R.I. 005 2P where it passes through Fire Zone 8, is satisfactorily resolved, since the combination of automatic fire detection and automatic fire suppression in con.iunction with the one-hour fire barrier wrap conforms to guidelines of the Standard Review Plan, Pranch Technical Position 9.5.-1 and the Section III.G.2.c of Appendix R to 10 CFR 5 We have also concluded that the other two Region III open items concerning electrical feeds passing through Fire Zone AB-2 have been satisfactorily resolved. Resolution of open item 341/85050-04 (6.g.(2) in the January 3, 2986 Inspection Report) is acceptable because of the combination of (1)

automatic fire detection and suppression, (2) one-hour fire rated wraps provided for one division of safe shutdown cables, (3) 20-feet of spatial separation that is free of intervening combustibles between unprotected trays of redundant divisions of safe shutdown cables, and (4) fire stops installed on horizontal cable trays that are located in the 20-foot clear space between redundant divisions of safe shutdown cables. Resolution of open item 3A1/85050-05 (6.g.(3) in Inspection Report dated January 3, 1986) is acceptable because of (1) indication functions available, independent of Fire Zone AP-2, at the dedicated (3L) shutdown panel and in the control room, and (2) changes 'in the procedures to require an operator to ranua11y open the Division II Heat Exchanger Temperature Control Valve in the event of fire in Fire Zone AR-2 to assure it is a safe configuration,

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-4-In addition to these conclusions based upon the above evaluation Region III conducted a follow-up inspection on June 30 - July 1, 1986. In their letter to the licensee dated July 21, 1986, covering the results of that inspectio Pegion III found the actions of the licensee acceptable with respect to these three open items and closed each of them (341/85050-03, -04 and -05).

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