View source for TXX-4886, Interim Deficiency Rept CP-86-42 Re Class 1E Instrumentation & Control Cabinet Power Supply Breakers.Initially Reported on 860604.Evaluation Continuing.Next Rept Will Be Submitted by 860730

{{Adams
| number = ML20206S364
| issue date = 06/27/1986
| title = Interim Deficiency Rept CP-86-42 Re Class 1E Instrumentation & Control Cabinet Power Supply Breakers.Initially Reported on 860604.Evaluation Continuing.Next Rept Will Be Submitted by 860730
| author name = Counsil W
| author affiliation = TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
| addressee name = Johnson E
| addressee affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION IV)
| docket = 05000445, 05000446
| license number = 
| contact person = 
| document report number = CP-86-42, TXX-4886, NUDOCS 8607070339
| document type = DEFICIENCY REPORTS (PER 10CFR50.55E &amp; PART 21), TEXT-SAFETY REPORT
| page count = 1
}}

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Log # TXX-4886 File # 10110 908.3 TEXAS UTILITIES GENERATING COMPANY SKYWAY TOWER = 400 NORTH 01JVE STREET. L.B. N B
* DALLAS. TEXAS 75208 June 27, 1986                                                    --
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2@30MM3                                   i Mr. Eric H. Johnson, Director                                                        Jll - 2l986 Division of Reactor Safety and Projects                                      ~
p U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76012

==SUBJECT:==
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 I&C CABINET POWER SUPPLY BREAKERS SDAR:   CP-86-42 (INTERIM REPORT)

==Dear Mr. Johnson:==

On June 4,1986, we verbally notified your Mr. I. Barnes of a deficiency involving Class 1E I&C cabinet power supply breakers. This is an interim report of a potentially reportable item under the provisions of 10CFR50.55(e).
Various Class 1E I&C cabinets eith redundant DC power supplies are fed DC power through a common supply breaker which is in turn fed by individual supply breakers from each power supply. The overcurrent trip setting on the individual supply breakers is higher than the overcurrent trip setting for the common supply breaker, which means that an overcurrent condition in one DC power supply can trip the common supply breaker and result in the loss of both DC power supplies. We are continuing our evaluation and anticipate submitting our next report by July 30, 1986.
Very truly yours,
                                                                       /
W. G. Counsil JCH/arh c - NRC Region IV (0 + 1 Copy)                                                                                                 ;
Director, Inspection & Enforcement (15 copies)                                                                            i U. S. Nuclear Regulatory Commission                                                                                       '
Washington, D.C. 20555                                                                                                    )
8607070339 860627                    fi                                             .
PDR    ADOCK 05000445                TJ S                     PDR            F R-W/
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