ML18053A346
| ML18053A346 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 04/21/1988 |
| From: | Miller H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Heins G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8804280589 | |
| Download: ML18053A346 (2) | |
Text
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Docket No. 50-255 Consumers Power Company ATTN:
Gordon L. Heins Senior Vice President Energy Supply 1945 West Parnall Road Jackson, MI 49201 Gentlemen:
APR 2 1 1988 During the special safety. inspection conducted by Mr.
z~ Fa~evits of this office on September 16 through October 23, 1986, a concern was identified pertaining to the overloading of the feeder cables to 2400 volt Bus lE (non-Class lE) and the potential. for overloading the feeder cables to 240rr volt Bus lD (Class lE).
At the time of this inspection, you provided the NRC.*
with copies of ~alculations No.
EA-D-PAL-86-198~02 and -03, dated October 17, 1986, showing the ampacity of the cables and concluding that no significant degradation of the ~ables had resulted from overloads. Subsequent to these calc~lations, your staff re-evaluated the cable ampacities and concluded that
- the previous 1986 calculations were not conservative in modeling the cable systems as installed in undergro~nd concrete duct banks.
Consumers Power Company then retained the services of Bechtel to re-evaluat~ the cable ampacities using a Bechtel computer model that had been verified agairist th~
Insulated Power. Cable Engineers Association (IPCEA) Publication Number P-46-426.
You provided the results of this evaluation to the NRC by letter and attachment dated January 28, 1988.
We have reviewed this analysis and coriclude (as discussed in the enclosed evaluation) that there is reasonable assurance that the cables to safety Buses lC and lD are adequate for the worst case design basis accident.
We also conclude that these cable have not experienced any* significant therinal degradation due to startup, shutdown or surveill~nce testing of the unit unless significant overloads have occurred in the past that we are unaware of.
Calculations No.
EA-D-PAL~86-I98~02 indicate that ~hart term overloads have occurred on the feeder cables to non~safeguards Bus IE.
Our review of the hand calculations suggests that the methodology used may significantly understate the thermal degradation that may have occurred on the cables from the station power transformer to the non-safeguards Bus IE.
While these cables are physically and electrically separated from the cables from the startup transformer to the safeguards Buses IC and ID, a fault on the cable to Bus IE would take o~t one of the offsite sources required by GDC I7. Therefore, ~e request that you re-eval~ate the thermal d~gradation that may have occ~rrea to these cables due to past overloads.
Such re-evaluation should be consistent with the Arrhenius methodology.
The written results of your re~evaluation should be submitted to this office within thirty days of your receipt of th.is letter.
8804280589 880421 PDR ADOCK 05000255 Q
Consumers Power Company 2
APR 2 11988 The contact on this matter is Mr. R. Gardner (312/790-5524).
We will gladly discuss any questions you have regarding this issue.
Enclosure:
As stated cc w/enclosure:
Mr. Kenneth W. Berry, Director Nuclear Licensing Gerald B. Slade, Pl~nt General Manager DCD/DCB (RIDS)
Licensing. Fee Man~gement Branch M. Virgilio, NRR T. Q.uay, NRR T. Wambach, NRR E. Greenman, RIII W. Guldemond, RIII Resident Inspector, RIII Ronald Callen, Michigan Public Service Commission Michigan Department of Public Health R~II R'\\i.1' Gardner/jk 04/21/88 RJAJ
~ess 04g.l /88 Sincerely, Hubert J. Mi 11 er, Di rector Division of Reactor Safety RllJ J A ~,r Ch~
4 imos 04'2--\\ /BB
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