View source for PNO-III-90-046, on 900709,partial Loss of Offsite Power Occurred During Refueling Outage.Determined That Technician Failed to Insert Relay Logic Block.Licensee Reviewing Controls on Switchyard Activities.State of IA Notified

{{Adams
| number = ML20055G348
| issue date = 07/11/1990
| title = PNO-III-90-046:on 900709,partial Loss of Offsite Power Occurred During Refueling Outage.Determined That Technician Failed to Insert Relay Logic Block.Licensee Reviewing Controls on Switchyard Activities.State of IA Notified
| author name = Hague R
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION III)
| addressee name = 
| addressee affiliation = 
| docket = 05000331
| license number = 
| contact person = 
| document report number = PNO-III-90-046, PNO-III-90-46, NUDOCS 9007230079
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
{{#Wiki_filter:F~~u IPRdlMINARYtiOTIFICATIONOFEVENT-ORUNUSUALOCCURRENCEPNO-Ill-90-46DateJuly 11.-1990 f:       . .         \
h Thish preliminary n;tificati:n constitutes EARLY notice of events of POSSIBLE safety or p:blic
/ ; interest significance. The information is as initially received without verification or
;      ;valuatiAn,' and is basically all that is known by the Region 111 staff on this date.                (}g
{
Facility:. Iowa Electric Light &          Licensee Emergency
!..                   Power                         Classification:                   .
Duane Arnold Energy             X Unusual Event                                                  '
Center                           Alert Palo, I A 52324                    Site Area Emergency General Emergency Docket No. 50 331                  Not Applicable

==Subject:==
PARTIAL LOSS OF 0FFSITE POWER At 10:33 a.m. (CDT), July 9, 1990, during a refuoling outage, the standby transformer s:ddenly lost power. This caused a temporary lots of off-site power to both 4160 volt                         <
ess:ntialbuses(1A3and1A4). Offsite power rerained to the non-essential 4160 volt buses.
All fuel had previously been removed from the reactor. The A emergency diesel generator was out of service at the time, but the B diesel generator was available.
    ' The power loss occurred during relay testir.g in the switchyard. The licensee determined that a technician failed to insert a relay logic block, thereby tripping a supply breaker to the standby transformer. This caused busses 1A3 and 1A4 to lose power. A suisequent full R: actor Protection System (RPS) scram signal and Primary Containment Isolation System (PCIS) group 1 through.5 isolation signals were received. (No rod motion occurred because of refueling activities. Isolation of some PCIS valves were also blocked because of maint: nance.tagouts.)
Tha 1A4 bus was r^ energized inmediately by the B Emergency Diesel Generator.        Bus IA3 r:mained deenergiced for about 40 minutes until power was restored to the standby transformer.
The licensee declared an Unusual Event at 11:31 a.m. (CDT), July 9, 1990, in accordance with its Emergency Classification System. The Unusual Event was terminated at 11:54 a.m. (CDT).                    '
    - The licensee is currently reviewing its controls on all switchyard activities. -
    . Region'111 (Chicago) is monitoring the licensee's course of action.
     .TheLState of Iowa will be notified.       This information has been reviewed with licensee manag: ment.                                                                                                  .
Region 111 was notified of this event at 11 a.m. (CDT), July 9,1990. This information is currsnt as of 9 a.m. (CDT), July 11, 1990.
CONTACT:6 . Hague (FTS 388-5546)                          .K [(FTS388-5547)
DISTRIBUTION:
HEADQUARTERS OFFICES              REGIONS               MAIL T0:
Chairman Carr        NMSS              Region 1               DCS (Orig)                                   (  '
GPA:SP            Region 11              DOT (Tranc.                                   ,
Cornm. Rogers        GPA:PA            Region IV                   Only)
Comm. Curtiss        GPA:CA            Region V                                               / ',
Comm. Remick         *0lG EDO
    ' Gen. Counsel
                            *ASLAP Research FAX T0:
INP0 /01/4 NSAC /O!40 LIC /OW2
                                                                                                    /
                                                                                                      /    /[ 1 l
                                                                                                                \
NRR                  1RM            NRC OPTCTR      / O.'.7
* 9007230079 900711 AE0D -               ACRS           PDR (8/634-33T3)       70N           PDR    I&E PNO-III-90-046 PDC Enforcement (Denotes a Displaywriter/PC not an IBM 5520 Terminal.                 .       Rev. 06/22/90}}

{{PNO-Nav|region=III}}