View source for PNO-III-85-093B, on 851029,reactor Trip Breaker & Associated Undervoltage Trip Actuating Device Failed.Breaker Mods Expected to Be Completed on 851105.Elements of Confirmatory Action Ltr Met Except for Cause of Device Failure

{{Adams
| number = ML20209H282
| issue date = 11/04/1985
| title = PNO-III-85-093B:on 851029,reactor Trip Breaker & Associated Undervoltage Trip Actuating Device Failed.Breaker Mods Expected to Be Completed on 851105.Elements of Confirmatory Action Ltr Met Except for Cause of Device Failure
| author name = Chrissotimos N, Hehl C
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION III)
| addressee name = 
| addressee affiliation = 
| docket = 05000316
| license number = 
| contact person = 
| document report number = PNO-III-85-093B, PNO-III-85-93B, NUDOCS 8511110061
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
{{#Wiki_filter:PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-III-85-938         Date Novembe          B5 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety r public interest significance. The information is as initially received without varification or evaluation, and is basically all that is known by the Region III staff on this date.
Facility: American Electric Power                   Licensee Emergency Classification:
D. C. Cook Nuclear Plant                     Notification of an Unusual Event Stevensville, MI 49127                       Alert Site Area Emergenc Docket Nos: 50-315; 50-316                   General Emergency XX   Not Applicable

==Subject:==
FAILURE OF REACTOR TRIP BREAKER (SECOND UPDATE)
The augmented incident response team, with staff from Region III (Chicago), Office of Nuclear Reactor Regulation, Office of Inspection and Enforcement, and a consultant, remained on site until November 2, 1985. The Region III special inspection effort c)ntinues.
Th failed reactor trip breaker and its associated undervoltage trip actuating device (UVTA) were t:sted and inspected by the licensee with NRC observers present. The testing was able to reproduce the failure of the undervoltage trip actuating device, but did nct identify the root caus5 of the failure. The equipment is to be shipped to an outside laboratary for further testing and cvaluation. NRC and licensee observers will be present for the additional analysis.
T; sting of the second Unit 2 reactor trip breaker (which successfully tripped the reactor on Octob r 29,1985), also resulted in a similar failure of the undervoltage trip actuating device.
The Unit 2 reactor trip breakers are being modified by the installation of automatic shunt trip attachments. This modification is expected to be completed on November 5, 1985, followed by testing of the reactor trip breakers and restart of the unit. All elements of the Oct:ber 30, 1985, Confirmatory Action Letter have been met except for determining the root cause of the UVTA failure, authorization to restart and submission of a formal report.
The Unit 1 breakers had previously been modified. The unit is continuing its refueling outaga startup testing program.
The State of Michigan will be informed of this updated information. This information is current as of 10 a.m. (CST), November 4 1985.
CONTACT:       H 11               (    rYssdimos FTS 388-5552          F S 388-5716 DISTRIBUTION:
H. St. f57)                 ED0        NRR        E/W / $ U Willste g Mail: ADM:DMB Chairman Palladino          PA                    IE         NMSS                D0T:Trans only Comm. Zech                  ELD                  OIA         RES Com. Bernthal                                    AE0D Comm. Roberts Comm. Asselstine ACRS SPc2tJO    Regional Offices     [N SECY                        INP0/;y         NSAC //30 CA                          RIII Resident Office        /d PDR                         Licensee: //34             _ (Corp. Office - Reactor Lic. Only) 8511110061 851104                                                            /
PDR     I&E                                                                i PNO-II I-85-093 PDR                                 Region III           XJg Dmt  th v u r t 10DK}}

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