U.S. Nuclear Regulatory Commission Operations Center Event Reports For 08/02/94 - 08/03/94 ** EVENT NUMBERS ** 27619 27620 +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27619 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: ROBINSON REGION: 2 |NOTIFICATION DATE: 08/02/94 | |UNIT: [2] [ ] [ ] STATE: SC |NOTIFICATION TIME: 06:35 [ET]| |RX TYPE: [2] W-3-LP |EVENT DATE: 08/02/94 | +------------------------------------------------+EVENT TIME: 05:54[EDT]| |NRC NOTIFIED BY: JAMES CONDER |LAST UPDATE DATE: 08/02/94 | |HQ OPS OFFICER: DOUG WEAVER +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: UNUSUAL EVENT +-----------------------------+ |10 CFR SECTION: |CHARLES CASTO RDO | |AAEC 50.72(a)(1)(i) EMERGENCY DECLARED |JOHN ZWOLINSKI EO | | |RIGHT FEMA | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 2 | M/R Y 100 POWER OPERATION | 0 HOT STANDBY | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | UNUSUAL EVENT DECLARED DUE TO THE FAILURE OF A PORV TO CLOSE AFTER | | ACTUATION | | | | A LOAD REJECTION CAUSED A TURBINE RUNBACK. OPERATORS MANUALLY TRIPPED THE | | REACTOR WHEN THEY OBSERVED THE TURBINE RUNBACK AND LOAD REJECTION. THE | | SUBSEQUENT RISE IN REACTOR PRESSURE CAUSED ONE PORV (RC 455C) TO LIFT. THIS | | PORV CURRENTLY INDICATES INTERMEDIATE. OPERATORS CLOSED THE BLOCK VALVE | | WHEN THEY NOTICED THE ABNORMAL POSITION INDICATION. OPERATORS ARE UNSURE | | WHETHER THE REACTOR COOLANT SYSTEM PRESSURE DROP WAS ALREADY TERMINATED | | WHEN THEY SHUT THE BLOCK VALVE. A REVIEW OF THE PLANT COMPUTER LOGS WILL | | BE CONDUCTED TO PROVIDE THIS INFORMATION. | | | | ALL RODS FULLY INSERTED DURING THE TRIP. ONE ROD BOTTOM LIGHT DID NOT | | ENERGIZE, HOWEVER THE INDIVIDUAL ROD POSITION INDICATION FOR THAT ROD | | INDICATED THAT IT IS FULLY INSERTED. THE STEAM GENERATORS ARE BEING FED ON | | THE BYPASS BY MAIN FEEDWATER AND THE MAIN CONDENSER IS AVAILABLE AS A HEAT | | SINK. | | | | THE CAUSE OF THE LOAD REJECTION IS NOT KNOWN. THE LICENSEE INTENDS TO | | BORATE TO HOT SHUTDOWN. THE UNUSUAL EVENT WILL BE TERMINATED WHEN THE PORV | | IS VERIFIED TO BE SHUT. THE PORV PROBLEM IS SUSPECTED TO BE AN INDICATION | | PROBLEM AND NOT A PROBLEM WITH THE ACTUAL OPERATION OR POSITION OF THE | | VALVE. | | | | THE LICENSEE INFORMED THE RESIDENT INSPECTOR AND THE APPROPRIATE STATE AND | | LOCAL OFFICIALS. | | | | | | * * * UPDATE AT 0717 ON 8/2/94 BY CONDER TAKEN BY WEAVER * * * | | | | SITE MANAGEMENT DECIDED TO TERMINATE THE UNUSUAL EVENT BASED ON THE BLOCK | | VALVE BEING SHUT AND NO LEAKAGE TO THE PRT. | | | | HOO NOTIFIED FEMA (BECLCHER), EO (GOODWIN), RDO (CASTO) | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27620 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: BRAIDWOOD REGION: 3 |NOTIFICATION DATE: 08/02/94 | |UNIT: [ ] [2] [ ] STATE: IL |NOTIFICATION TIME: 20:32 [ET]| |RX TYPE: [1] W-4-LP,[2] W-4-LP |EVENT DATE: 08/02/94 | +------------------------------------------------+EVENT TIME: 17:49[CDT]| |NRC NOTIFIED BY: BAL |LAST UPDATE DATE: 08/02/94 | |HQ OPS OFFICER: CHAUNCEY GOULD +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |JAMES CREED RDO | |ARPS 50.72(b)(2)(ii) RPS ACTUATION | | | | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | | | | | 2 | A/R Y 100 POWER OPERATION | 0 HOT STANDBY | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | THE PLANT HAD A REACTOR TRIP FROM 99.9% POWER ON "2A" STEAM GENERATOR LO-2 | | TRIP. | | | | THE LO-2 S/G LEVEL TRIP WAS CAUSED BY THE "2A" FEED REG VALVE FAILING | | CLOSED (CAUSE OF ITS FAILURE IS BEING INVESTIGATED). ALL RODS FULLY | | INSERTED AND NO SAFETY RELIEF VALVES LIFTED. BOTH AUX FEEDWATER PUMPS AUTO | | STARTED ON LOW S/G LEVEL CAUSED BY SHRINK. AT 18:38 THE STARTUP FEEDWATER | | PUMP WAS STARTED AFTER THE S/G LEVELS WERE RESTORED AND THE AUX FEEDWATER | | PUMPS WERE PLACED IN STANDBY SOON AFTER. THEY WILL REMAIN IN MODE 3 UNTIL | | THE PROBLEM IS CORRECTED. THE RI WAS INFORMED. | | | | HOO NOTE: DURING THE MORNING STATUS CALL ON 08/03/94, THE LICENSEE | | STATED THAT THE CAUSE OF THE EVENT WAS FAILURE OF O-RINGS | | ON THE FEEDWATER REG VALVE. THESE O-RINGS ARE ON THE AIR | | OPERATOR FOR THE VALVE. WHEN AIR PRESSURE DROPPED IN THE | | CONTROLLER, THE VALVE FAILED CLOSED. | +------------------------------------------------------------------------------+