ML070030427

NFPA 805 Transition Pilot Plant FAQ 06-0018

ML070030427
Person / Time
Site:	Harris
Issue date:	11/06/2006
From:	Progress Energy Co
To:	Office of Nuclear Reactor Regulation
References
06-0018, Rev 0, NUREG/CR-6850
Download: ML070030427 (2)

Text

FAQ Number 06-0018, Revision 0 1 Plant: Harris Nuclear Plant (HNP) FAQ # 06-0018 Rev. 0 Submittal Date: 11-6-06 Licensee Contact: David Miskiewicz Tele/email 919-546-7588 NRC Contact: Tele/email Distribution: Check all that apply (NEI Internal Use)

FPWG RIRWG NSSS OG NFPA 805 TF

Subject:

Clarification/enhancement of Ignition Sour ce counting guidance for Main Control Board (MCB) in NUREG/CR-6850, supporting N FPA-805 Fire PRA application.

Interpretation of guidance?

Yes Proposed new guidance not in NEI 04-02?

Yes Details: NEI 04-02 Guidance needing interpretation (inc lude section, paragraph number, and line number): New attachment on interpretation issues Circumstances requiring guidance interpretation or new guidance:

NUREG/CR-6850, Section 6.5.6

The guidance provided in NUREG/CR-6850 for Task 6, Fire Ignition Freque ncy, is subject to application inconsistency in the treatment of Main Control Board (Bin 4). The guidance for Task 6 does not provide any specific definition or characterization of what constitutes a Main Control Board (MCB) other than a reference to it being the central element of the room. A discussion amongst the Pilot Plants that included considerati on of other plants in their respective fleets found wide variability in the configuration of the main control room. There was a concern that inconsistent treatment of this bin would unnecessarily challenge the completion and review of the Fire PRA. This challenge would be manifested by a notable change in the fire frequency assigned to an individual pa nel depending on whether it was counted as Bin 4 or Bin 15.

Further review of NUREG/CR-6850 found that a definition of MCB is provided in Appendix L. However, this Appendix develops a fire modeling treatment of fire be havior within a panel enclosure. There was a concern that absent documented agreement, there could be a future challenge to the use of the definition in Appe ndix L for the purposes of Task 6, Bin 4 counting. Detail contentious points if licensee and NRC have not reached agreement This topic has impact on the NFPA-805 pilots, no n-pilots and other user s of NUREG/CR-6850.

Potentially relevant existing FAQ numbers:

This guidance is specific to th e characterization of Main Control Board for Bin 4 determination. The characterization and counting of electrical cabinets for Bin 15 determination is addressed by FAQ 06-0016.

Response Section It is proposed that the definition of Main Control Board provided in NUREG/CR-6850, Appendix L be accepted as also being applicable for Task 6, Bin 4 counting.

Basis: The guidance proposed will provide more consistency when determining plant specific control room ignition frequencies while working within the bounds of the exiting data provided by the NUREG. This should facilitate the review and acceptability of the results.