ML20141J578
| ML20141J578 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 04/22/1986 |
| From: | Miosi A COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 1615K, NUDOCS 8604280216 | |
| Download: ML20141J578 (5) | |
Text
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N Commonwealth E son
[
( j) one First Nitionil Plua. Chicago, lilenois C j Address Reply to: Post Office Box 767 g
Chicago, Illinois 60690 April 22, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC.
20555
Subject:
Byron /Braidwood Units 1 and 2 Supplemental Safety Evaluation Report for Physical Identicication and Independence of Rodundant Safety-Related Electrical Sys.tems FSAR Changes and S&L Design Manual Change NRC Docket 50-454/455 and 50-456/457
Reference:
February 25, 1985 V.S.
Noonan Letter to D.L.
Farrar
Dear Mr. Denton:
This letter is in response to the Supplemental Safety Evaluation Report which addressed our electrical separation criteria utilized in'the design and construction of Byron and Braidwood Stations.
In the evaluation, you found the lesser cable separation criteria acceptable.
In order to close the issue you requested that this criteria should be referenced in the FSAR and the term
" quasi-safety related" be defined in the Sargent and Lundy design criteria manual.
The following is our resolution of these items.
The separation distance of 12" vertical and 3" horizontal between safety-related and non-safety-related raceways is currently identified in the PSAR in Section 8.3.1.4.2.2 (Raceway Separation Criteria) item b.l.
on Page 8.3-16.
The separation criteria for safety-related cables in free-air in contact with a raceway containing non-safety-related cables and non-safety related cables in free air in contact with a raceway containing safety-related cables will be included in the next amendment to the FSAH.
Attached pages 8.3-17, 18, and 18a are those pages which will be included in this change.
8604280216 e60422 PDR ADOCK O 4
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c i The definition and design criteria for " quasi safety-related" has been included in Sargent and Lundy Design Criteria for Cable Separation.
The Design Criteria manual is identified as DC-EE-Ol-BB.
Revision 12 is dated 4-14-86.
Please direct any questions you may have regarding this matter to this office.
t One signed original and fifteen copies of this letter and enclosure are provided for your review.
Very truly yours, h
r A. D.
iosi Nuclear Licensing Administrator
/klj cc:
J. Stevens (NRC)
Resident Inspector-Byron Resident Inspector-Braidwood encl.
1615K
,-,,-,~.
b B/B-FSA R I
c.
Where termination arrangements or space limitations preclude maintaining the above space separations, the redundant cables are run in enclosed raceways that qualify as barriers, or other barriers shall be provided between redundant cables.
The minimum distance between these redundant enclosed raceways and between barriere and raceways is 1 inch.
d.
Basis for separation between cables in free-air and cables in cable trays:,
1.
Safety-related cables in free-air may come in contact with a cable tray containing non-safety-related cables.
2.
Non-safety-related cables in free-air may come in contact with a cable tray containing safety-related cables.
Conduit Segregation All conduit qualify as barriers.
The same rules have been applied to conduit segregation as were applied to cable tray segregation.
Conduit Separation l
a.
All power, control, and instrumentation cables are run in separate conduit.
b.
The minimum allowable separation between conduit in redundant ESF divisions is 12 inches.
However, where practical, the separation between conduits in redundant ESP divisions is the same as for cable trays.
c.
For instrument conduit within the same ESF Division, or related RTS channel, the following separation distances apply:
1.
Minimum vertical and horizontal separation between instrument conduit and control cable conduit as 1 inch.
2.
Minimum vertical and horizontal separation between instrument conduit and power cable conduit is:
(a)
Shielded instrument cables in conduit l
running parallel to power cables in conduit where the parallel run is less than 100 feet have 1-inch minimum separation.
If the 8.3-17
a B/B-FSAR conduits run parallel for a distance greater than 100 feet, 1-inch separation is used in some cases for a distance not exceeding 100 feet, the remaining separation is 3 inches minimum.
Where practical, the 3-inch minimum separation has been maintained.
(b)
Unshielded instrument cables in canduit are rua a minimum of 3 inches from control
. cables in conduit and 20 inches from power cables in conduit.
d.
The minimum vertical and horizontal separation between conduit in redundant RTS channels is 24 inches.
Nuclear instrumentation signal (triaxial) cables are run in steel conduit.
e.
Nuclear instrumentation system (NIS) triaxial cable conduit is separated from electrical noise sources by the following distances:
1.
control or low voltage power cable in conduit -
24 inches.
l 2.
medium voltage power cables in conduit - 6 feet (72 inches); and 3.
control, low, and medium voltage cables in trays
- 6 feet (72 inches).
f.
Where instrument cable (other than NIS triaxial) conduit and cable trays within the same division are installed adjacent to each other, the following separations apply:
1.
instrument conduit to power cable tray - 20
- inches, 2.
instrument conduit to control cable tray - 3
- inches, 3.
control cable conduit to instrument cable tray -
12 inches, and 4.
power cable conduit to instrument cable tray - 20 i
inches.
8.3-18 l
l
. * -. s B/B-FSAR g.
For cables in free-air to cables in conduit, the following separation distances apply:
1.
Safety-related cables in free-air may come in L
contact with a conduit containing non-safety-related cables.
2.
Non-safoty-related cables in free-air may come in l
contact with a conduit containing safety-related cables.
8.3.1.4.3 Cable Separation Criteria Cable Segregation A segregation code assigned to each cable is used to check all cables routed in cable traye or conduit for compliance with the required segregation.
This cable segregation code appears in the installation cable tabulation and on applicable physical installation drawings.
The segregation code consists of one.or more characters as indicated in the following summary:
i t:
8.3-18a l
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