ML20207A980
| ML20207A980 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/30/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20207A948 | List: |
| References | |
| RTR-REGGD-01.075, RTR-REGGD-1.075 NUDOCS 8611110425 | |
| Download: ML20207A980 (1) | |
Text
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15 f
ENCLOSURE LESSER SEPARATION BETWEEN CLASS IE AND CERTAIN NON-CLASS 1E CIRCUITS COMANCHE PEAK UNITS 1 AND 2 In letters dated September 25, 1984, and slanuary 7,1985, the Texas Utilities Generating Company identified that non-Class IE public address system speaker cables and area radiation monitoring detector cables in the. plant are not l
separated from the Class IE wiring as recommended by IEEE-384 as endorsed by R.G. 1.75.
For the cables identified, the applicant performed an analysis to demonstrate that the non-Class IE cables will not cause the failure of the adjacent Class IE cables.
We have reviewed the analysis of the typical cases presented by the applicant i
and conclude that the area radiation monitoring detectors and the public address system speaker cables are low energy level circuits which are designed to provide a maximum of 5 watts and 12 watts, respectively, under fault l
condition. Therefore, with this level of power, it is highly unlikely that any adjacent cables would be affected under fault condition. Moreover, the Class IE circuits are run in conduits which provide a barrier between the Class 1E and the above low energy level circuits. This lesser separation is provided only for short runs (18" for speaker cables and 6' for radiation monitoring detector cables) when the non-1E cables come out of the conduits to be connected to their respective devices. Therefore, any damage in the non-Class IE circuits will be limited to the non-Class IE and will not be propagated to nearby Class IE circuits. Rased on the above, the staff finds there is reasonable assurance that electrical faults in the subject non-Class IE cables will not degrade Class IE circuits. Therefore, the staff finds this concern acceptably resolved.
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