ML20116M094

Submits Supplemental Info Re Concerning Addendum 1 to NEDO-10466, Power Generation Control Complex (Pgcc) Fire Suppression Licensing Topical Rept. Establishment of Halon Concentration Requirement for Control Room Discussed

ML20116M094
Person / Time
Site:	05000447
Issue date:	05/01/1985
From:	Villa R GENERAL ELECTRIC CO.
To:	Thomas C Office of Nuclear Reactor Regulation
References
MFN-58-85, NUDOCS 8505060105
Download: ML20116M094 (2)

Text

NED0-10466 Addendum 1 GENERAL $ ELECTRIC NUCLEAR ENERGY BUSINESS OPERATIONS GENERAL ELECTRIC COMPANY

• 175 CURTNER AVENUE

• SAN JOSE, CAUFORNIA 95125 MC 682, (408) 925-5722 May 1, 1985 MFN '58-85 U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C. 20555 Attention: C. 0. Thomas, Chief Standardization & Special Projects Branch Gentlemen:

SUBJECT:

POWER GENERATION CONTROL COMPLEX (PGCC) FIRE SUPPRESSION LICENS-ING TOPICAL REPORT ADDENDUM 1 - SUPPLEMENTAL INFORMATION

Reference:

MFN-29-85 dated February 28, 1985 We would like to amplify upon several points which were made in our previous request (reference letter) for establishing a specific Halon concentration and soak time requirement for control rooms where the cable insulation is primarily Tefzel within the PGCC.

We want to emphasize that deep seated burning of the non-Tefzel cable insula-tion (less than 20% of the total insulation) in the control room PGCC is not possible for the following reasons:

First, only power cables are supplied with sufficient electrical energy to possibly initiate a cable insulation fire. Since all power cables are in flexible metallic conduit within the PGCC, any burning of insulation initiated by this electrical source will be confined to the conduit in which the over-heating occurs.

Another reason that deep seated burning will not occur is that a cable fire introduced by an ignition source within the PGCC must be initiated in the surface burning mode and then progress to the deep seated mode of burning. The automatically initiated fire suppression system will extinguish the ignition source and any resultant cable fire while the cable insulation is still burning in the surface mode. This conclusion is substantiated by the fact that the 10-minute required minimum soak time for the fire suppressant envelopes the transition from surface burning to deep seated burning (first minimum of curve at about 5 minutes) exhibited in the fire test reported in Figure 4.2 of NED0-10466. Automatic initiation of the suppressant system ensures extinguish-ing before deep seated burning is initiated.

10 8505060105 850501 7 ADOCK 050 gDR s .I i

t l' USNRC GENER AL $ ELECTRIC May 1, 1985 Page 2 We also want to emphasize there is additional information available now as compared to that which was available in 1976 to justify the inclusion of a predominately Tefzel insulated control room with a required Halon concentration of 6% for 10 minutes. The basis for this justification are the three addition-al items of information in the following paragraphs.

The first item is that the applicable control rooms are built and it is an established fact that the cable insulation is at least 80% Tefzel. The origi-nal requirements of 20% Halon concentration for 20 minutes was based on cables with non-Tefzel insulation. It is appropriate to establish the requirement for the "as-built" condition of the control rooms.

The second item is that redundant remote shutdown capability has been provided external to the control rooms for the applicable plants. This makes it possi-ble to be much more aggressive in combatting fires in the control room.

The third item relates to a series of fire tests conducted at Sandia Laborato-ries and summarized in NUREG/CR-2607. The cable tray configuration and igni-tion source were not similar to what might be encountered in the PGCC, but some :-

conclusions applicable to the PGCC may be drawn. Fully developed deep seated fires were initiated in cable trays which contained primarily non-Tefzel insulated cables which were then totally flooded with Halon 1301 at a 6%

concentration. A 10-minute soak time extinguished the deep seated fires and prevented re-ignition upon reintroduction of air to the tray. The extinguish-ing action should be just as effective in the PGCC if for some reason discharge of Halon was delayed until a fire had progressed to deep seated burning in the small amount of non-Tefzel cable insulation which could be present in a PGCC floor section.

Please contact R. D. Hickman on (408) 925-4584 should you have any questions.

Very truly yours,

/

R. Villa, Manager Product Licensing RV:rm/A05015 cc: L. S. Gifford G. G. Sherwood D. Moran i D. C. Scaletti

NED0-10466 Addendum 1 GENER AL $ ELECTRIC NUCLEAR ENERGY BUSINESS OPERATIONS GENERAL ELECTRIC COMPANY

• 175 CURTNER AVENUE

• SAN JOSE, CAUFORNIA 95125 MC 682, (408) 925-3392 MFN- 2?-85 February 28, 1985 U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C. 20555 Attention: C. O. Thomas, Chief Standardization & Special Projects Branch Gentlemen:

SUBJECT:

POWER GENERATION CONTROL COMPLEX (PGCC) FIRE SUPPRESSION LICENSING TOPICAL REPORT ADDENDUM 1 The purpose of thie letter is to transmit a special report which documents in Addendum 1 to NED0-10466 an additional Halon concentration and soak time option for the PGCC's fire suppression system.

We request a review and safety evaluation report (SER) for referencing and licensing actions by Utility applicants, i.e. Illinois Power Company, Gulf States Utilities, etc. This fire suppression option has been discussed by John Stang, NRC, Ed Maxwell, GE, and various Utility representatives. We request an expedited review schedule, i.e. two to four weeks after receipt of this letter.

Under separate correspondence to William 0. Miller, NRC, we have provided the

$150.00 application fee.

Please contact R. D. Hickman on (408) 925-4584 should you have any questions.

Very truly yours, f

H. C. fefferlen Manager BWR Licensing Programs HCP:csc/IO2213 Attachments cc: L. S. Gifford, w/Att G. G. Sherwood, w/o Att D. Moran (NRC), w/Att D. C. Scaletti (NRC), w/o Att 4;16@r875Nb p- ..