ML20133N995
| ML20133N995 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 08/06/1985 |
| From: | Miosi A COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20133N999 | List: |
| References | |
| 0475K, 475K, NUDOCS 8508140097 | |
| Download: ML20133N995 (2) | |
Text
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Commonw:cith Edison One First National Plaza, Chicago, lihnoes Address Reply to. Post Office Box 767 Chicago. Illinois 60690 August 6, 1985 l
l Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Byron Unit 2 Braidwood Units 1 and 2 Supplemental Request for Additional Information on Separation CriteriaO NRC Docket Nos. 50-455,50-456/456]
ReferJace (a):
July 15, 1985 BJ. Youngblood Letter to DL. Farrar
Dear Hr. Denton:
Enclosed is the engineering response with supporting documentation in response to your request to perform an evaluation of separation criteria of Class IE from non-class IE cables.
Commonwealth Edison Company's electrical separation criteria utilized in the design and construction of Byron and Braidwood Stations is stated in Section 8.3 of the Byron /Braidwood FSAR.
The separation criteria which was established between redundant Class IE raceways is consistent with NRC Regulatory Guide 1.75 and IEEE Std. 384-1974.
However, the criteria for separation of non-Class lE from Class lE cable raceways is established at the reduced distance of 12 inches vertical and 3 inches horizontal which deviates from the separation criteria of Regulatory Guide 1.75.
In keeping with Byron /Braidwood's commitment to Regulatory Guide 1.75 as stated in Appendix A to the FSAR, a calculation has been prepared to justify the lesser separation between Class lE and Non-Class lE Sargent & Lundy calculation number Q-13 (" Justification raceways.
for Electrical Separation Distances Between Safety-Related and Non-Safety-Related Raceways", Rev. O, dated August 1, 1985) was prepared in accordance with IEEE 384-1974 and Byron /Braidwood's commitment to Regulatory Guide 1.75.
A copy of this calculation is submitted for your review.
In addition, in order to justify the electrical separation distance between Class lE and non-Class lE cables when one is in a raceway and the other is routed in free-air, Sargent & Lundy calculation number Q-14 (" Justification for Electrical Separation b**\\ /
10P 8
8508140097 850806 PDR ADOCK 05000455 A
.;4.i, Between Safety-Related and Non-Safety-Related Cables When One is in Free-Air and the Other is_in a Raceway", Rev. O, dated August 1, 1985) has been prepared.
This calculation has been prepared in accordance with Byron /Braidwood's commitment to Regulatory Guide 1.75 and IEEE Std. 384-1974, and is submitted for your review.
An expeditious review of our response is requested in light of the upcoming August. CAT audit at Byron Unit 2.
This would serve both of our-interests with resolution of this issue.
Please direct any questions you or your staff may have regarding this matter to this office.
One signed original and fifteen copies of this letter and enclosures are provided for your review.
Very truly yours, iV?ty A. D. Miosi Nuclear Licensing Administrator
/klj cc:
J. Stevens (NRC) 0475K