ML20010A292
| ML20010A292 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 07/17/1981 |
| From: | Koch L, Kock L ILLINOIS POWER CO. |
| To: | Norelius C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20010A288 | List: |
| References | |
| 0981-L, 981-L, U-0264, U-264, NUDOCS 8108110285 | |
| Download: ML20010A292 (2) | |
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0981-L U-0264 ILLINDIS POWER 00MPANY Q37-81(07-17)-L 500 SOUTH 27TH STREET, DECATUR, ILLINOl',62525 July 17, 1981 Mr. C.E. Norelius Acting Director Division of Engineering and Technical Inspection U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 61037
Dear Mr. Norelius:
This is a supplemental response to our July 5, 1981 letter which responded to your Notice of Violation and Inspection Report number 50-461/81-09.
The additional concerns expressed in your followup letter of June 19, 1981 have also been considered in developing this response.
1.
Flexible Conduit Used For Electrical Separation The GE PGCC design does not depend upon flexible conduit to provide a fire barrier between the wiring inside the conduit and the wiring outside the conduit.
In the CPS design, there is no need for a fire barrier because internal fires are effectively prevented by the circuit fusing.
This is considered acceptable because all conduits are grounded to ensure that hot shorts in internal wiring will melt upstream fuses, providing short circuit protection triat limits the fault to the net-divis!cnal cables.
Con-sequently, this design application is consistent with NEDO 10466A.
2.
Flexible Conduit Used as Part of a Fire Barrier Based on results from fire tests, we conclude that flexible l
conduit passing through a fire barrier between two divisional i
ducts does not compromise the integrity of that fire barrier.
Fire seals are provided wherever conduit penetrates a divi-sional boundary (external to the conduit).
Fire tests have ahown that a fire in a wiring duct containing flexible conduit did not propagate through the fire barrier containing the conduit.
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C. E. Norelius July 17, 1981' Page 2-Based on the foregoing, Il'11nois Power' considers the use of flexible conduit in the PGCC.derign for fire protection, intercom, and utility services wiring to ha acceptable.
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Illinois Power does, however, agree that an interpretational discrepancy does exist between the Clinton PGCC design and the-PGCC Topical Report NEDO-10466A.
To address this discrepancy,Jwe will modify the FSAR, Section 8.3, to describe and justify the Clinton PGCC design and to reconcile it with the wording in Topical 1
Report (NEDO-10466A).
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We expect t'o amend the FSAR by the end of 1981.
In summary, we have. reviewed the issue of separation associated with the flexible conduit as used in PGCC and find the installation to be consistent with good design practices and the results.of.
PGCC fire tests.
When the FSAR has.been revised, it will document full compliance with regulatory requirements.
I trust that our response is satisfactory to allow closeout of this issue when all i
actions are complete.
I hereby affirm that the information contained-in this letter is correct to the best of my knowledge.
l
- Sincerely, s
N, j
L J. Koch Vice President
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cc:
H. H. Livermore, NRC Resident Inspector Director-Quality Assurance i
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