U.S. Nuclear Regulatory Commission Operations Center Event Reports For 07/11/94 - 07/12/94 ** EVENT NUMBERS ** 27516 27517 27518 27519 27520 27521 27522 +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27516 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: DUANE ARNOLD REGION: 3 |NOTIFICATION DATE: 07/11/94 | |UNIT: [1] [ ] [ ] STATE: IA |NOTIFICATION TIME: 00:09 [ET]| |RX TYPE: [1] GE-4 |EVENT DATE: 07/10/94 | +------------------------------------------------+EVENT TIME: 22:01[CDT]| |NRC NOTIFIED BY: MANKIN |LAST UPDATE DATE: 07/11/94 | |HQ OPS OFFICER: GREG SCARFO +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |JOHN JACOBSON RDO | |ARPS 50.72(b)(2)(ii) RPS ACTUATION | | |AESF 50.72(b)(2)(ii) ESF ACTUATION | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | M/R Y 100 POWER OPERATION | 0 HOT SHUTDOWN | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | A MANUAL REACTOR SCRAM WAS INITIATED IN RESPONSE TO A LARGE ELECTRO | | -HYDRAULIC CONTROL (EHC) SYSTEM FLUID LEAK. | | | | IN RESPONSE TO AN EHC FLUID LOW LEVEL ALARM AND CONFIRMED A SIGNIFICANT EHC | | FLUID LEAK, OPERATORS INITIATED A MANUAL REACTOR SCRAM. ALL RODS FULLY | | INSERTED ON THE SCRAM. A TURBINE TRIP OCCURRED ON REVERSE GENERATOR POWER, | | AS EXPECTED. REACTOR WATER LEVEL "SHRUNK" TO 160 INCHES, BELOW THE LOW | | LEVEL REACTOR SCRAM/GROUP ISOLATION SETPOINT OF 170 INCHES. A GROUP 2 | | (DRYWELL SUMP VALVES) ISOLATION, GROUP 3 (PRIMARY AND SECONDARY | | CONTAINMENT) ISOLATION, GROUP 4 (SHUTDOWN COOLING) ISOLATION, AND GROUP 5 | | (REACTOR WATER CLEANUP) ISOLATION OCCURRED. AFTER REACTOR WATER LEVEL | | RECOVERED ABOVE 170 INCHES, OPERATORS CLEARED THE ISOLATIONS AND RESET THE | | SYSTEMS. A RECIRCULATION SYSTEM RUNBACK TO 20% OF MAXIMUM RECIRCULATION | | FLOW OCCURRED ON THE DECREASE IN FEED FLOW, AS EXPECTED. NO SAFETY/RELIEF | | VALVES LIFTED DURING THE SCRAM. NO OTHER ESF OR ECCS ACTUATIONS OCCURRED. | | ALL ELECTRICAL LOADS TRANSFERRED PROPERLY TO OFFSITE POWER. | | | | BYPASS VALVES WERE UTILIZED INITIALLY TO DISSIPATE DECAY HEAT, HOWEVER, | | OPERATORS OPENED STEAM LINE DRAIN VALVES TO PROCEED WITH THE COOLDOWN, | | CLOSED THE BYPASS VALVES, AND SECURED THE EHC SYSTEM. | | | | CURRENTLY, THE UNIT IS STABLE IN HOT SHUTDOWN. THE MAIN FEEDWATER SYSTEM | | IS FEEDING THE VESSEL AND STEAM LINE DRAINS ARE BEING UTILIZED TO DISSIPATE | | DECAY HEAT. OFFSITE POWER IS SUPPLYING ALL ELECTRICAL LOADS AND ALL | | EMERGENCY DIESEL GENERATORS ARE OPERABLE. | | | | THE CAUSE OF THE EHC LEAK IN UNDER INVESTIGATION AT THIS TIME. THE | | LICENSEE INFORMED THE NRC RESIDENT INSPECTOR. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27517 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: NINE MILE POINT REGION: 1 |NOTIFICATION DATE: 07/11/94 | |UNIT: [1] [ ] [ ] STATE: NY |NOTIFICATION TIME: 00:51 [ET]| |RX TYPE: [1] GE-2,[2] GE-5 |EVENT DATE: 07/11/94 | +------------------------------------------------+EVENT TIME: 00:01[EDT]| |NRC NOTIFIED BY: ALEJANDRO |LAST UPDATE DATE: 07/11/94 | |HQ OPS OFFICER: GREG SCARFO +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |JACK DURR RDO | |ARPS 50.72(b)(2)(ii) RPS ACTUATION | | | | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | A/R Y 85 POWER OPERATION | 0 HOT SHUTDOWN | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | AN AUTOMATIC REACTOR SCRAM OCCURRED FOR UNKNOWN REASONS. | | | | WHILE INCREASING TO 100% POWER, AN AUTOMATIC REACTOR SCRAM OCCURRED FOR | | UNKNOWN REASONS. ALL RODS FULLY INSERTED AND AN AUTOMATIC TURBINE TRIP | | OCCURRED ON THE REACTOR SCRAM, AS EXPECTED. REACTOR WATER LEVEL "SHRUNK" | | TO 25 INCHES, WELL BELOW THE LOW-LEVEL REACTOR SCRAM SETPOINT OF 53 INCHES. | | ONLY ONE OF TWO FEEDWATER COOLANT INJECTION (FWCI) PUMPS ACTUATED ON THE | | TURBINE TRIP. ALL OTHER PLANT SYSTEMS RESPONDED AS EXPECTED. | | | | CURRENTLY, THE UNIT IS STABLE IN HOT SHUTDOWN. THE MAIN FEED SYSTEM IS | | SUPPLYING THE VESSEL AND DECAY HEAT IS BEING DISSIPATED TO THE CONDENSER | | VIA BYPASS VALVES. OFFSITE POWER IS SUPPLYING ELECTRICAL LOADS AND ALL | | EMERGENCY DIESEL GENERATORS ARE OPERABLE. | | | | AN INVESTIGATION IS UNDERWAY TO DETERMINED THE CAUSE OF THE SCRAM AND THE | | REASON FOR THE DEFICIENT FWCI PUMP RESPONSE. THE LICENSEE INFORMED THE NRC | | RESIDENT INSPECTOR. | | | | * * * UPDATE 07/11/94 0310EDT FROM:ALEJANDRO BY:SCARFO * * * | | A POST-TRIP ANALYSIS HAS DETERMINED THAT A FAILURE OF THE ELECTRONIC | | PRESSURE REGULATOR (EPR) CAUSED TURBINE CONTROL VALVES TO CLOSE, A REACTOR | | COOLANT SYSTEM (RCS) PRESSURE SPIKE, AND AN ASSOCIATED AVERAGE POWER RANGE | | MONITOR (APRM) HIGH (FLOW-BIASED) SCRAM SIGNAL. APRMs REGISTERED A HIGH | | POWER MEASUREMENT OF 107% PRIOR TO THE SCRAM. AN INVESTIGATION INTO THE | | FAILED COMPONENT OF THE EPR IS ONGOING. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27518 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: WATTS BAR REGION: 2 |NOTIFICATION DATE: 07/11/94 | |UNIT: [1] [2] [ ] STATE: TN |NOTIFICATION TIME: 07:28 [ET]| |RX TYPE: [1] W-4-LP,[2] W-4-LP |EVENT DATE: 07/11/94 | +------------------------------------------------+EVENT TIME: 05:25[EDT]| |NRC NOTIFIED BY: BAKER |LAST UPDATE DATE: 07/11/94 | |HQ OPS OFFICER: GREG SCARFO +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |PIERCE SKINNER RDO | |APRE 50.72(b)(2)(vi) OFFSITE NOTIFICATION |CHAFFEE EO | | |BEECHER PAO | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | N N 0 UNDER CONSTRUCT | 0 UNDER CONSTRUCT | | 2 | N N 0 | 0 | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | A DEMONSTRATION OCCURRED WHICH DISRUPTED THE ENTRY OF WORKERS TO THE PLANT. | | | | AT 0525EDT, THE SHIFT SUPERVISOR WAS INFORMED OF A PLANNED ANTI-NUCLEAR | | GROUP DEMONSTRATION AT THE BOUNDARY OF THE OWNER-CONTROLLED AREA. THE | | DEMONSTRATION OCCURRED JUST PRIOR TO THE BEGINNING OF THE NEW SHIFT AND | | 75-100 DEMONSTRATORS BLOCKED THE ENTRANCE OF THE FACILITY. AT 0650EDT, AN | | INTRUDER WAS REPORTED TO THE SHIFT SUPERVISOR. AN INVESTIGATION FOUND NO | | SUCH INTRUDER. AT 0655EDT, THE SHIFT SUPERVISOR AUTHORIZED THE ARREST OF | | DEMONSTRATORS BY LOCAL LAW ENFORCEMENT AUTHORITIES. THIS ACTION BROKE UP | | THE DEMONSTRATION AND ALLOWED ACCESS TO THE FACILITY BY EMPLOYEES. | | PROTESTERS REMAIN AT THE FACILITY BUT ARE NO LONGER BLOCKING THE ENTRANCE. | | REGION II(FREDERICKSON) WAS NOTIFIED BY THE LICENSEE. THE LICENSEE | | INFORMED THE NRC RESIDENT INSPECTOR. LOCAL PRESS HAVE REPORTED THE | | INCIDENT. A PRESS RELEASE IS ANTICIPATED. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27519 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: HADDAM NECK REGION: 1 |NOTIFICATION DATE: 07/11/94 | |UNIT: [1] [ ] [ ] STATE: CT |NOTIFICATION TIME: 09:30 [ET]| |RX TYPE: [1] W-4-LP |EVENT DATE: 07/11/94 | +------------------------------------------------+EVENT TIME: 09:13[EDT]| |NRC NOTIFIED BY: HEFFERNAN |LAST UPDATE DATE: 07/11/94 | |HQ OPS OFFICER: GREG SCARFO +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: UNUSUAL EVENT +-----------------------------+ |10 CFR SECTION: |JACK DURR RDO | |AAEC 50.72(a)(1)(i) EMERGENCY DECLARED |GRIMES EO | |ARPS 50.72(b)(2)(ii) RPS ACTUATION |HUGHES FEMA | |AESF 50.72(b)(2)(ii) ESF ACTUATION |CHAFFEE EO | | |BROCKMAN AEOD | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | M/R Y 100 POWER OPERATION | 0 HOT STANDBY | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | AN NOUE WAS DECLARED WHEN A MANUAL REACTOR TRIP WAS INITIATED DUE TO HIGH | | REACTOR COOLANT PUMP (RCP) BEARING TEMPERATURE. | | | | AT 0735EDT, A LOW-LEVEL OIL RESERVOIR ALARM FOR RCP #3 OCCURRED AND | | ELEVATED TEMPERATURES FOR RCP #3 THRUST BEARING AND UPPER GUIDE BEARING | | WERE DISCOVERED. BEARING TEMPERATURES CONTINUED TO INCREASE SLOWLY AND, AT | | 0833EDT, OPERATORS INITIATED A LOAD REDUCTION. WHEN BEARING TEMPERATURES | | EXCEEDED 190 DEGREES F (WITH REACTOR POWER AT 50%), A MANUAL REACTOR TRIP | | WAS INITIATED. ALL RODS FULLY INSERTED ON THE TRIP. STEAM GENERATOR (SG) | | #1 FEEDWATER REGULATING VALVE DID NOT CLOSE ON THE REACTOR TRIP. OPERATORS | | RESPONDED BY MANUALLY CLOSING THE FEEDWATER ISOLATION VALVE AND THE "STEAM | | LINE TRIP VALVE". WHILE THE FEED REG VALVE WAS OPEN, LEVEL IN SG #1 | | INCREASED TO 74%, ABOVE THE 69% FEEDWATER ISOLATION SETPOINT. THE COOLDOWN | | RATE DID NOT EXCEED THE TECHNICAL SPECIFICATION LIMIT. OTHER PLANT | | RESPONSES TO THE REACTOR TRIP WERE AS EXPECTED. NO OTHER ESF OR ECCS | | ACTUATIONS OCCURRED. | | | | THE UNIT IS STABLE IN HOT STANDBY. THE MAIN FEEDWATER SYSTEM IS SUPPLYING | | SGs VIA BYPASS VALVES. DECAY HEAT IS BEING DISSIPATED TO THE CONDENSER VIA | | THE STEAM DUMP VALVES. OFFSITE POWER IS SUPPLYING ALL ELECTRICAL LOADS. | | THE ECCS AND EMERGENCY DIESEL GENERATORS ARE OPERABLE AND AVAILABLE. | | THE CRITERION FOR ENTERING THE NOUE WAS THE ACT OF SHUTTING DOWN THE PLANT | | WITH A COMPLICATION (ELEVATED THRUST BEARING TEMPERATURE). THE CRITERION | | FOR EXITING THE NOUE IS THE DISCOVERY OF THE CAUSE OF THE ELEVATED THRUST | | BEARING TEMPERATURE. AN INVESTIGATION INTO THE CAUSE IS ONGOING. | | | | * * * UPDATE 07/11/94 1004EDT FROM:HEFFERNAN BY:SCARFO * * * | | UPON ENTRY INTO CONTAINMENT TO INVESTIGATE THE CAUSE OF THE ELEVATED THRUST | | BEARING TEMPERATURE, A SMALL FIRE WAS DISCOVERED. A FIRE BRIGADE WAS | | DISPATCHED INTO CONTAINMENT. THE SOURCE OF THE FIRE IS SOME OIL-SOAKED | | PIPE LAGGING ASSOCIATED WITH THE RCPs. THE LICENSEE INFORMED THE NRC | | RESIDENT INSPECTOR. R1DO(DURR), EO(GRIMES, CHAFFEE), AEOD(KARSCH, BROCKMAN) | | NOTIFIED. | | | | * * * UPDATE 07/11/94 1137EDT FROM:SMITH BY:SCARFO * * * | | THE FIRE HAS BEEN EXTINGUISHED. AN OIL LEAK FROM RCP #3 WAS THE CAUSE OF | | THE FIRE ON THE PIPE LAGGING OF THE #3 RCP "BOWL". THE FIRE LASTED | | APPROXIMATELY SEVEN MINUTES. A "REFLASH" WATCH HAS BEEN STATIONED IN | | CONTAINMENT. THE UNIT REMAINS IN THE NOUE. THE LICENSEE INFORMED THE NRC | | RESIDENT INSPECTOR. STATE AND LOCAL AGENCIES NOTIFIED. R1DO(DURR), | | EO(CHAFFEE), AEOD(ROSS, BROCKMAN, KARSCH) NOTIFIED. | | | | * * * UPDATE 07/11/94 1437 EDT FROM HEFFERNAN TAKEN BY WEAVER * * * | | UNUSUAL EVENT TERMINATED AT 1437EDT. OIL LEAK HAS BEEN STOPPED. THE PLANT | | IS COOLING DOWN TO ABOUT 400F TO REPAIR LAGGING DAMAGE. HOO NOTIFIED R1 | | RDO(SHANBAKY), EO(CHAFFEE), FEMA(MUSE), AEOD(KARSCH). | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27520 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: CALVERT CLIFFS REGION: 1 |NOTIFICATION DATE: 07/11/94 | |UNIT: [ ] [2] [ ] STATE: MD |NOTIFICATION TIME: 13:20 [ET]| |RX TYPE: [1] CE,[2] CE |EVENT DATE: 07/11/94 | +------------------------------------------------+EVENT TIME: 12:30[EDT]| |NRC NOTIFIED BY: KENT MILLS |LAST UPDATE DATE: 07/12/94 | |HQ OPS OFFICER: DOUG WEAVER +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |MOHAMED SHANBAKY RDO | |ASHU 50.72(b)(1)(i)(A) PLANT S/D REQD BY TS | | | | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | | | | | 2 | N Y 100 POWER OPERATION | 97 POWER OPERATION | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | SMALL LEAK (.15 GPM) ON A SAFETY INJECTION TANK TEST CONNECTION LINE | | | | THE PLANT COMMENCED SHUTDOWN AT 1315 EDT AT 25% PER HOUR BECAUSE OF RCS | | PRESSURE BOUNDARY LEAKAGE. THE LEAK WAS DISCOVERED DURING A CONTAINMENT | | ENTRY TO INVESTIGATE A HIGHER THAN NORMAL LEAKAGE RATE ON THE "A" SAFETY | | INJECTION TANK. THE LEAK IS ON A WELD ON THE 22A TEST CONNECTION LINE. THE | | TEST CONNECTION LINE IS A 3/4" LINE. THE LEAK IS CONSIDERED RCS PRESSURE | | BOUNDARY LEAKAGE EVEN THOUGH THE LEAKING WATER IS COMING FROM THE SAFETY | | INJECTION TANK. SAFETY INJECTION TANK PRESSURE IS ABOUT 215 PSIG. | | | | SOME ADDITIONAL SUPPORTS WERE ADDED TO THE INJECTION LINE DURING THE LAST | | REFUELING SHUTDOWN. THE PLANT IS ANALYZING THE POSSIBILITY OF FATIGUE | | FAILURE AS A CAUSE OF THE LEAK DUE TO THE INSTALLATION OF THESE SUPPORTS. | | | | THERE IS A DEENERGIZED OPEN MOV AND A CHECK VALVE BETWEEN THE LEAK AND THE | | RCS. THE PLANT IS REQUIRED TO BE IN HOT STANDBY WITH SIX HOURS AND COLD | | SHUTDOWN WITHIN THE NEXT 30 HOURS. REPAIR OPTIONS ARE BEING EVALUATED AT | | THIS TIME. | | | | THE LICENSEE HAS NOTIFIED THE NRC RESIDENT AND MADE A COURTESY CALL TO THE | | CALVERT CONTROL CENTER. | | | | * * * UPDATE 07/12/94 0254EDT FROM:SCHICK BY:SCARFO * * * | | THE UNIT IS STABLE IN MODE 3 (HOT STANDBY). THE LICENSEE PLANS ON | | PROCEEDING TO HOT SHUTDOWN, LEAVE TWO REACTOR COOLANT PUMPS IN SERVICE, | | ISOLATE LEAK (AND ASSOCIATED SIT), AND AFFECTED REPAIR OF THE LEAK. R1DO() | | NOTIFIED. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27521 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: PERRY REGION: 3 |NOTIFICATION DATE: 07/11/94 | |UNIT: [1] [ ] [ ] STATE: OH |NOTIFICATION TIME: 23:38 [ET]| |RX TYPE: [1] GE-6 |EVENT DATE: 07/11/94 | +------------------------------------------------+EVENT TIME: 21:54[EDT]| |NRC NOTIFIED BY: RABENOLD |LAST UPDATE DATE: 07/11/94 | |HQ OPS OFFICER: DOUG WEAVER +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: | | |AESF 50.72(b)(2)(ii) ESF ACTUATION | | | | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | N N 0 COLD SHUTDOWN | 0 COLD SHUTDOWN | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | RHR ISOLATION DUE TO INADEQUATE WORK PROCEDURE | | | | DURING THE REPLACEMENT OF A LEAKY INSTRUMENT ISOLATION VALVE THE RHR TRIP | | UNIT SET POINT WAS REACHED AND AN RHR ISOLATION OCCURRED (135 PSIG). THE | | NEW VALVE HAD BEEN INSTALLED AND WAS BEING LEAK TESTED. VALVE 1E12FOO8 | | WENT SHUT (COMBINED RHR SUCTION ISOLATION). RHR PUMP "B" WAS MANUALLY | | TRIPPED WHILE THE SUCTION ISOLATION VALVE WAS IN MID STROKE. OPERATORS WERE | | UNSURE AS TO WHEN THE PUMP SHOULD HAVE TRIPPED (I.E. WHAT VALVE POSITION) | | AND ARE INVESTIGATING THIS ASPECT OF THE EVENT. | | | | THE ISOLATION OCCURRED AT 2154 EDT, RHR WAS RESTORED AT 2247 EDT AFTER | | FILLING AND VENTING THE RHR B LOOP. REACTOR COOLANT TEMPERATURE ROSE FROM | | 100F TO 102F. THE WORK PROCEDURE DID NOT CONTAIN ANY STEPS TO PREVENT THE | | PRESSURE FROM THE LEAK TEST FROM REACHING THE DETECTOR OR SOME OTHER MEANS | | OF PREVENTING THE SIGNAL FROM CAUSING AN ESF ACTUATION. | | | | THE NRC RESIDENT WAS INFORMED. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 27522 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: COOPER REGION: 4 |NOTIFICATION DATE: 07/12/94 | |UNIT: [1] [ ] [ ] STATE: NE |NOTIFICATION TIME: 05:12 [ET]| |RX TYPE: [1] GE-4 |EVENT DATE: 07/12/94 | +------------------------------------------------+EVENT TIME: 02:45[CDT]| |NRC NOTIFIED BY: LAPLANT |LAST UPDATE DATE: 07/12/94 | |HQ OPS OFFICER: GREG SCARFO +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: | | |ARPS 50.72(b)(2)(ii) RPS ACTUATION | | |AESF 50.72(b)(2)(ii) ESF ACTUATION | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | A N 0 COLD SHUTDOWN | 0 COLD SHUTDOWN | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | A REACTOR SCRAM SIGNAL AND A SHUTDOWN COOLING ISOLATION OCCURRED WHEN TWO | | OF FOUR CHANNELS OF LEVEL INSTRUMENTATION FAILED LOW. | | | | AT 0245CDT, A REACTOR SCRAM SIGNAL AND GROUP 2 (SHUTDOWN COOLING), GROUP 3 | | (REACTOR WATER CLEANUP), AND GROUP 6 (PRIMARY CONTAINMENT AND SECONDARY | | CONTAINMENT) ISOLATIONS OCCURRED WHEN TWO OF FOUR CHANNELS OF LEVEL | | INSTRUMENTATION FAILED LOW. THE LEVEL DOWN-SPIKE CAUSED "A" AND "B" | | CHANNEL INSTRUMENTATION TO REGISTER A LOW REACTOR WATER LEVEL OF 0 INCHES, | | BELOW THE 4.5 INCH REACTOR SCRAM SETPOINT. AFTER THE SPIKE, THE AFFECTED | | INSTRUMENTS FAILED UPSCALE. ACTUAL VESSEL LEVEL REMAINED AT 50 INCHES | | THROUGHOUT THE EVENT. NO ROD MOTION OCCURRED DUE TO THE SCRAM SIGNAL. | | | | AT 0304CDT, SHUTDOWN COOLING WAS RETURNED TO SERVICE. REACTOR COOLANT | | SYSTEM TEMPERATURE INCREASED APPROXIMATELY 3 DEGREES, FROM 111 DEGREES F TO | | 114 DEGREES F (AS MEASURED AT THE INLET OF THE REACTOR WATER CLEANUP HEAT | | EXCHANGER). THE REMAINING ISOLATIONS WERE CLEARED, AS WELL, AND THE PLANT | | WAS RETURNED TO ITS NORMAL (COLD SHUTDOWN) CONFIGURATION. | | | | THE CAUSE OF THE FAILED LEVEL INSTRUMENTATION IS BELIEVED TO BE AIR BUBBLES | | IN THE REFERENCE LEGS OF THE LEVEL INSTRUMENTATION SYSTEM. NO MAINTENANCE | | OR REPAIRS WERE BEING PERFORMED ON THE SYSTEM AT THE TIME OF THE EVENT. AN | | INVESTIGATION TO CONFIRM THE CAUSE OF THE EVENT IN UNDERWAY. | +------------------------------------------------------------------------------+