ML19329B753
| ML19329B753 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/11/1976 |
| From: | Szukiewicz A Office of Nuclear Reactor Regulation |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8002060763 | |
| Download: ML19329B753 (6) | |
Text
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Docket :40. 50-346-
- lenorandu:a for: Thomas A. Ippolito, Chief, Electrical, Instrunentation and Control Syste:::s Branch, L65 Froc:
Andrew J. 5:ukiewicz, Electrical, Instrumentation and Control Systens Branch, DSS Thru:
Charles F. ? tiller, Section Leader, tiectrical, CQf""[;
Instrumentation and Control Systens 3 ranch, CSS
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SLMfARY OF METI:!G UIT:I TOLE.;O EDISC.i CCMPKiY REGARDINC DAVIS BESSE LSIT 1 SEPARATIO:; CRITERIA A neeting was held in Bethesca, :-faryland, on October 23, 1976, with Toledo Edison Conpany to discuss the separation criteria for wireways and conduits in general plant areas and the cable spreading rocu. This teeting was a followup to our site visit of October 6, 7, and d, 1976, addressing tne staff's concerns identified at the site (see Iten 16 of the site visit re; ort dated :;ovenbcr 4,1976). Attacned as Enclosurc 1 is a list of attendees. identifies the concerns e:: pressed by the staff and their resolation.
l'roject :lanagement is reqacsted to transait tha inforuation adurcssed la j
dnclosare 2 to the applicant in order to assure taat their r:spenses to our concerns are consistent with waat was agreed upca caring the necting.
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[s Andrew J. S:akiewic:
Electrical, Instrumentation and Control Systens Branch Division of Systems Safety Enclosuras:
As stated
Contact:
A. J. 3:ukiewicz a
Ext. 27387 c'
Distribution
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ENCLOSURE 1 MEETING ATTENDEES DAVIS BESSE, UNIT 1 L. Engle NRC J. Stol:
NRC A. Ungaro NRC R. Wright ACRS A. S:ukiewic:
NRC C. Miller NRC G. Stashih Bechtel J. Reilly Bechtel S. Saba Bechtel
- 5. Cantor Bechtel P. Anas Bechtel F. Cheng Bechtel D. Hayes NRC-Region III F. Jablonski NRC-Region III G. !!urrell TECo.
M. Calcar.uggio TECo.
L. Roe TECo.
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Fa2.1 ENCLOSURE 2
. In a recent Amendment (36) to the FSAR the applicant described their proposed separation criteria for cable routing for general plant areas and in t*
cable spreading room (FSAR Figure S-20 A, B, and C). The staff expresse'd concern that the proposed separation criteria as~ documented in Amendment-36 appeared to be inconsistent with information previously submitted and discussed with NRC Region III Inspection and Enforcement, and NRC Licensing.. The applicant was requested and agreed to (1) supple-ment the FSAR and provide justification for the proposed separation criteria used fo,r cables routed in conduits, (2) clarify the apparent discrepancies in their proposed criteria, and (3) document the fo11cwing ' commitments agreed upon during the meeting.
1.
The applicant stated-that their separation criteria for totally covered trays, wireways and conduits is the same and committed to document this criteria in the FSAR.
2.
The applicant pointed out that limited amounts of "CCC" cable used for intercommunication between redundant i
safety logic cabinets are routed in wireways. This cable has not been verified by test to have equivalent flame retardant properties as the cables previously reviewed by the staff. To resolve the staff's concerns regarding fire in wireways, the applicant commited to inject flame retardant
" silica rubber foam" inside the safety related wireways J
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2 wherever.this cable is routed, and document this commitment in the FSAR. They will also provide justification supporting the adequacy of the fire characteristics of this material.
3.
The applicant agreed to document in the FSAR the following criteria for redundant safety related wireways when routed over open trays.
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cea Toe Taays a.
If "A" is less than 46 inches, adequate barriers.. extending
- hori:ontally no less than 12 inches to each side of the wireway between the open tray and the wireway, will be provided to preclude fire damage of redundant safety related wireways in the event of fire in the open tray.
b.
If "B"fis less than 24 inches, an adequate fire barrier will be provided between the redundant wireways.
-During the discussion, the applicant was advised that their
-design requirements for fire protection shculd be consistent with the requirements stated in Appendix A of Regulatory Position 9.5.1.
4.
.The applicant was requested and agreed to document in the FSAR that when thermal barriers are provided in areas where
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minimum hori: ental distances between redundant trays
,4 and/or wireways is less than one inch, these thermal barriers would extend beyond these raceways with sufficient overlap (i.e., approximately Isnch beyond the top of the tray and/or wireway and approximately l inch beyond the i
bottom of the tray or wireway).
S.
The staff's concern regarding cable routing in metal conduits could not be resolved during the meeting and remains an open item in the SER. The staff requested that the applicant justify their proposed cri teria (as stated in Figure 8.20 A, B, and C of the FSAR, ALendment 36) in arer' where redundant conduits are rcuted over open trays or modify their design to be compatible with the criteria established for wireways (see Item 4 and Item 1).
The applicant indicated that they may submit test results of the fire tests that were conducted on these conduits as their justification, or consider other alternatives.
In addition, the applicant identified that in areas throughout the plant.the safety related redundant conduit may be touching each other. Subsequent to the meeting the staff reviewed this design feature and concluded that such a design is unacceptable.
It is the staff's position that redundant conduits must be separated by at least one inch of free air space or suitable thermal barriers be provided. The applicant is ~ requested to document the implementation of this requirement in the FSAR.
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The applicant stated that thermal. blankets (Kawool or 4
equivalent) will be provided on all open cable trays with
- certain exceptions (e.g., trays inside containment and within the cable spreading area). The applicant was requested to document this commitment in the FSAR, identify all. exceptions and justify these exceptions on some other i
defined basis.
In addition, the staff is pursuing with the applicant the possibility of whether these blankets can be justified.for use as barriers in other portions of the plant such as the cable spreading area.
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