ML19329A815

Submits Criteria Amplifying Note 9,Figure 3-20A of FSAR & Superseding Criteria in 761123 Ltr.Ser Outstanding Item 15 Re Conduit Separation Should Be Completed

ML19329A815
Person / Time
Site:	Davis Besse
Issue date:	01/31/1977
From:	Roe L TOLEDO EDISON CO.
To:	Stolz J Office of Nuclear Reactor Regulation
Shared Package
ML19329A811	List: ML19329A810 ML19329A815
References
NUDOCS 8001150710
Download: ML19329A815 (2)

Text

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0017, E-14 5 EDISDN Docket No. 50-346 LOWfLL E. ROE v.ca Preenent January 31, 1977 , ,.u .. o.w... .. .

d4191253 5242 -

Serial No. 205 Director of Nuclear Reactor Regulations Attn: Mr. John F. Stolz, Chief Light Water Reactors Branch No. 1 D@G

g Division of Project Management d United States Nuclear Regulatory Commission M'@'- I f

q, Washington, D.C. 20555 g g - sg ~ .

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Dear Mr. Stoir:

One remaining open item concerning electrical separation criteria (SER Outstanding Item 15) for the Davis-Besse Unit 1, is the criteria for conduit separation. During discussions in October and November, 1976

.with the HRC staff, we stated that a 1-inch separar. ion between conduit carrying redundant essential class IE circuits had not been a criteria

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during the construction of the station. To impose such a criteria at this time would require rework, including removal and reinstallation in

/ a mimber of cases, based on a physical review and field check of conduit installation. This resulted in my letter, Serial No. 157, of November 23, 1976.

The tests and analysis program committed to by us in my November 23, 1976

. letter has been completed and the results hava shown that in most situa-tions and cembinaticns of circuits, physical separation of conduit carrying redundant essential class IE circuits is not necessary. A copy of a proprietary preliminary report of the extensive test program conducted at Franklin Institute- Research Laboratories was .given to Mr. Szukiewicz of the NRC staff during a meeting on January 14, 1977.

Based on the results of_this test and analysis program, separation criteria for class IE conduit has been es~tablished which assures that (1) any failure or occurrence in a class IE conduit will net degrade a redundant essential' class IE circuit in adjacent class IE conduits, (2) a failure or occurrence in a non-class. IE co,nduit will not degrada redundant' essential class IE circuits in adjacent class IE conduits.

The criteria established are as follows:

1. Conduits carrying control, instrumentation, or pouer cable (where the power cable is limited to 480 volt or lower and No. 12 AWG or smaller) are allowed to touch each other.

THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MAO' EON AVENUE TOLEDO. CHIO 43052 8 0 011507/d

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- Mr. Jshn F. Stolz Page 2 U CF January 31, 1977 ,

2. Conduit carrying essential class IE 4.16 KV power cables or 480 volt load center power cables will have a 1-inch minimum separation from conduits carrying class IE circuits of a redundant channel.

3. Conduit carrying non-essential 13.8 Kv, 4.16 KV, or 480 volt load center power cabics that bridge conduits carrying essential class IE circuits of redundant channels will be separated from conduit carrying circuits of the redundant channel to give a minimum separation of 1 inch.

4. Conduit carrying essential class IE power cable of 480 volt or lower voltage with conductor size larger than number 12 AWG, and not covered by 2. above, will meet the following criteria:

a. Will have s minimum of 1/8-inch separation from the surface of any conduit crossing above which contains an essential class IE circuit of the redundant channel.

b. Are allowed to touch conduits containing an essential class IE circuit of the redundant channel wnen installed in a horizo'ntal, side-by-side configuration.

c. Will have a minimum separation of 1 inch from conduits containing an essential class IE circuit of the redundant

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channel mounted directly above and running parallel.

5. Conduit carrying non-essential power cable of 480 volt or lower voltage with conductor size larger than number 12 AUG, and not covered by 3. above, that bridge conduits carrying essential class IE circuits of redundant channels will be treated as in'4. a., b. and c. for proper separation from the redundant channel.

This above listed criteria is to apply to, and amplify Note No. 9 shown in Figure 8-20A of the Final Safety Analysis Report and supersedes the criteria contained in my letter, Serial No. 157, of November 23, 1976.

We trust that this will completely close SER Outstanding Item 15 concern-ing conduit separation. .

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Yours very truly, Lowell E. Roe LER.r t

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