View source for ST-HL-AE-3900, Special Rept:On 910913,output Breaker CS06 for Standby DG 23 Would Not Close on Demand from Control Room.Nonlicensed Operator Dispatched to Investigate Cause of Event.Caused by Inadequate Work Practices.Personnel Counseled

{{Adams
| number = ML20087F420
| issue date = 09/13/1991
| title = Special Rept:On 910913,output Breaker CS06 for Standby DG 23 Would Not Close on Demand from Control Room.Nonlicensed Operator Dispatched to Investigate Cause of Event.Caused by Inadequate Work Practices.Personnel Counseled
| author name = 
| author affiliation = HOUSTON LIGHTING &amp; POWER CO.
| addressee name = 
| addressee affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION IV)
| docket = 05000498, 05000499
| license number = 
| contact person = 
| document report number = ST-HL-AE-3900, NUDOCS 9201230139
| package number = ML20087F387
| document type = REPORTABLE OCCURRENCE REPORT (SEE ALSO AO LER), TEXT-SAFETY REPORT
| page count = 2
}}

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                        ,MI                                                                            ST.HL.AE*3900 pa.e l of 2 s
009y'                                                                                                       1 South Texas Project Electric Generating station                                        f Unit 2 Docket No STN 30 499
             !'                                                special Report Regarding A No wa11d i
                                            = jfailure of eM Etandhv Dianal am .armene en tagggebar IL 1991                                    I g --
DESC'RIFTIE M !
On septealcier 13. 1991, er approximately 0520 hours. Unit 2 was in Mode 1 at 1006 power. While performing the Train C Diesel Generator slave Relay Test,                                      !
                        '     the Output areaker C806 for e23 Standby Diesel Generator. ,$DG) would not close on demand from the so7 trol room. A Non licensed-Operator was dispatched to investigate the cause.                                                                                 ,
i 11ht dispatched eyeraf.                discovered that the diesel output breaker had not been                      !
fully racked in. The non Licensed operator was directed.to fully rack in the breaker. A sentrol room-operator was etn able -to restart the diesel, close the breaker. norpally, and .ontinue with the surveillance test.
It was .later estabits)e4 thac this occurred during the restoration of a alearance en che_ breaker for ,*ecent mechanical work on- the diesel's fuel
                            &nj ectors. The diesel had been declared inoperable at 0930 hours ~on september 12.c1991, to allow repair of the 9R fuel injector and its associated fuel line. :Following the repair, the ttesel. was' started at 1908 hours as a Post Maintenance Test (PNT). - The diesel rest.hed rated speed, frequency, and voltage within the required 10 seconds and showed as sigra of injector
                          ~probigns. . 11here was no requirement to electrically. Lead the diesel and the FN1' was: completed satisfactorily. The dien,el was declared operable at 2020 hours..
SDC m23 was, in reality, inoperable from 0930 hours on September 12, 1991 luntil 1220 haurs on September 14, 1991, for a total of 50 hours 50 minutes.
During = the same -time,- Unit 2 had descended to Mode 3-in preparation for s l                          scheduled refueling outage. The total diesel inoperability time was within -
i the 72 hours allowed by the 140 action statemnnt of Technical Specification E                          3.8.1.1 ar.d no ESF train 'A' or *3" compohents 'were declared inoperable while                                    i the 'C' Train diesel was unavailable.
CAUSE OF EVENT:
The cause of this event was' that work practices were less than adequate. The Non licensed Operators responsible for restoring the clearance on the e23 Standby OG A.15KV output breaker did not adequately verify that the expected breaker indications were received. - An additional root cause was that testing was 'less- than adequate. . The required Post Maintenance Testing (PMT) of the diesel did not verify that. the output breaker had been fully racked in by .
loadina' the diesel generator on the emergency bus.
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ATTACHMENT ST+HL AE M *h PAGE.i3      0F  _.l h                                                               Attachment        ,
st   \                                                        ST.itL. AE.3900 l        h, Al{lh                                                          Page 2 of 2 ,
COPN South Texas Project Klectric Generating Scation       :
Unit 2                             :
Docket No. STM $0 499 Special Report Regarding A Nonvalid Failure of e23 standby fludangrator en Emotamber 13,2 ANALYSIS OF EVENT:                                                        .
This event occurred as a result of a Non licensed operator not adequately racking in the Oatput Breaker on the diesel generator. Per the criteria in Regulatory Guide 1.108, this event has been classified as a non. valid failure, i
         . CORRECTIVE AqH QHE:                                                          .                 .
: 1. The Non-licensed Operators who failed to correctly rack in and verify the Diesel Output Breaker have been counseled by appropriate Plant Management on the need for and tarportance of self. verification.
: 2. 4at e scently qualified journeymen and apprentice Non.11 censed Operators
                 ' > demonstrated proficiency on breaker operations.
: 3.    *w c5 will develop a written policy that requires a closure under load M all safety.related 480V, 4.16KV, and 13.8KV breakers that are racked out for any reason, to ensure electrical continuity. '!his policy will be developed by November 1, 1991.
ADDITIONAL INPORMATION:
Per STPEGS Technical Specification 3.8.1.1, there have been no valid failures in the last 20 valid tests of the SDG #23 anC the number of valid failures in the last 100 valid tests is less chan five, therefore, the testing frequency for ESF SDC #23 remains at once per 31 days.
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