U.S. Nuclear Regulatory Commission Operations Center Event Reports For 06/16/98 - 06/17/98 ** EVENT NUMBERS ** 34402 34403 34404 +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 34402 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: CLINTON REGION: 3 |NOTIFICATION DATE: 06/16/98 | |UNIT: [1] [ ] [ ] STATE: IL |NOTIFICATION TIME: 08:44 [ET]| |RX TYPE: [1] GE-6 |EVENT DATE: 06/16/98 | +------------------------------------------------+EVENT TIME: 05:54[CDT]| |NRC NOTIFIED BY: HOLLAND |LAST UPDATE DATE: 06/16/98 | |HQ OPS OFFICER: CHAUNCEY GOULD +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |BRENT CLAYTON RDO | |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 +------------------------------------------------------------------------------+ | AN AUTOMATIC TRANSFER OF A SAFETY BUS OCCURRED DUE TO A POWER INTERRUPTION. | | | | A SHORT (0.3 SEC) INTERRUPTION IN POWER TO THE 138KV OFFSITE POWER SOURCE | | CAUSED AN AUTOMATIC TRANSFER OF THE '1C1' 4160V SAFETY BUS FROM THE | | EMERGENCY RESERVE AUXILIARY TRANSFORMER (ERAT) TO THE RESERVE AUXILIARY | | TRANSFORMER. THIS POWER INTERRUPTION WAS CAUSED BY A STORM IN THE AREA. | | THE OTHER TWO SAFETY-RELATED BUSES POWERED BY THE ERAT DID NOT TRANSFER, | | AND THEIR LOADS REMAINED ENERGIZED. NONE OF THE EMERGENCY DIESEL | | GENERATORS STARTED DURING THIS EVENT. CURRENTLY RESTORATION ACTIVITIES ARE | | UNDERWAY. | | | | THE NRC RESIDENT INSPECTOR WAS NOTIFIED BY THE LICENSEE. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 34403 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: VERMONT YANKEE REGION: 1 |NOTIFICATION DATE: 06/16/98 | |UNIT: [1] [ ] [ ] STATE: VT |NOTIFICATION TIME: 16:00 [ET]| |RX TYPE: [1] GE-4 |EVENT DATE: 06/01/98 | +------------------------------------------------+EVENT TIME: 17:09[EDT]| |NRC NOTIFIED BY: JAMES KRITZER |LAST UPDATE DATE: 06/16/98 | |HQ OPS OFFICER: STEVE SANDIN +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |HERB WILLIAMS RDO | |AINC 50.72(b)(2)(iii)(C) POT UNCNTRL RAD REL | | | | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | 1 | N Y 0 STARTUP | 97 POWER OPERATION | | | | | | | | | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | THE LICENSEE DISCOVERED DURING SURVEILLANCE TESTING THAT A DESIGN | | IMPLEMENTATION PERFORMED IN 1992 HAD RESULTED IN THE STANDBY GAS TREATMENT | | SYSTEM (SBGTS) FANS SUPPLY BREAKERS OVERLOAD TRIP SETPOINT BEING SET TOO | | LOW. | | | | [THE LICENSEE] IDENTIFIED [THAT] A CONFIGURATION CONTROL WEAKNESS DURING A | | 1992 DESIGN IMPLEMENTATION (APPARENTLY) RESULTED IN IMPROPERLY SET | | OVERLOADS IN [THE] REDUNDANT SBGTS FANS SUPPLY BREAKERS. [THE] 'B' SBGTS | | FAN TRIPPED DURING HPCI SYSTEM TESTING IMMEDIATELY AFTER START DUE TO A LOW | | OVERLOAD TRIP SETPOINT. [THE LICENSEE DETERMINED THAT THE] 'A' FAN HAD | | [THE] SAME SETPOINT. BOTH FANS HAVE PERFORMED SUCCESSFULLY ON A REGULAR | | BASIS DESPITE THE LOW TRIP SETPOINT. | | | | CORRECTIVE ACTIONS TAKEN INCLUDED: | | | | 1. FAN OVERLOAD SETPOINTS CORRECTED. | | | | 2. REVIEW COMPLETED OF MAINTENANCE RECORDS OF SIMILAR BREAKERS. | | | | 3. SINGLE NON-NUCLEAR SUPPLY (NNS) BREAKER FOUND WITH SIMILAR PROBLEM. | | | | THE LICENSEE INFORMED THE STATE OF VERMONT AND THE NRC RESIDENT INSPECTOR. | +------------------------------------------------------------------------------+ +----------------------------------+ +-----------------------+ |POWER REACTOR | |EVENT NUMBER: 34404 | +----------------------------------+ +-----------------------+ +------------------------------------------------+-----------------------------+ |FACILITY: BROWNS FERRY REGION: 2 |NOTIFICATION DATE: 06/16/98 | |UNIT: [ ] [2] [3] STATE: AL |NOTIFICATION TIME: 21:58 [ET]| |RX TYPE: [1] GE-4,[2] GE-4,[3] GE-4 |EVENT DATE: 06/16/98 | +------------------------------------------------+EVENT TIME: 20:25[CDT]| |NRC NOTIFIED BY: CHRIS VAUGHN |LAST UPDATE DATE: 06/16/98 | |HQ OPS OFFICER: STEVE SANDIN +-----------------------------+ +------------------------------------------------+ NOTIFICATIONS | |EMERGENCY CLASS: NOT APPLICABLE +-----------------------------+ |10 CFR SECTION: |ROBERT SCHIN RDO | |AOUT 50.72(b)(1)(ii)(B) OUTSIDE DESIGN BASIS | | | | | | | | | | | | | | +-----+----------+-------+--------+--------------+--+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | | | | | 2 | N Y 100 POWER OPERATION | 100 POWER OPERATION | | 3 | N Y 100 POWER OPERATION | 100 POWER OPERATION | +-----+---------------------------------------------+--------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | TECHNICAL SPECIFICATION 3.7.G.1.b MINIMUM NITROGEN VOLUME IS INSUFFICIENT | | FOR 7 DAY POST LOCA OPERATION OF THE CAD SYSTEM AS REQUIRED BY DESIGN. | | | | "THE CONTAINMENT ATMOSPHERIC DILUTION (CAD) SYSTEM AT BROWNS FERRY NUCLEAR | | PLANT (BFN) DESIGN BASIS REQUIRES SUFFICIENT NITROGEN STORED ONSITE TO | | ALLOW FOR 7 DAY POST LOSS OF COOLANT ACCIDENT (LOCA) OPERATION. DURING A | | REVIEW OF THE CAD SYSTEM CAPACITY FOR THE THERMAL POWER UPRATE PROGRAM, IT | | WAS DISCOVERED THAT THE CALCULATION FOR CAD NITROGEN VOLUME REQUIRED FOR 7 | | DAYS POST-LOCA WAS IN ERROR IN A NON-CONSERVATIVE MANNER. THIS ERROR HAS | | EXISTED SINCE THE ORIGINAL CAD SYSTEM DESIGN. AS A RESULT, THE AMOUNT OF | | NITROGEN REQUIRED TO BE STORED ONSITE IS NOT SUFFICIENT TO ENSURE THE | | CURRENT DESIGN BASIS FOR THE CAD SYSTEM IS MET. | | | | "CAD STORAGE TANK LEVELS WILL BE ADMINISTRATIVELY CONTROLLED SUCH THAT | | SUFFICIENT NITROGEN WILL BE AVAILABLE FOR 7 DAYS OF CAD SYSTEM OPERATION | | POST-ACCIDENT. SITE ENGINEERING IS EVALUATING THE BASIS FOR THE 7 DAY | | REQUIREMENT FOR THE CAD SYSTEM. | | | | "A WRITTEN REPORT WILL BE MADE WITHIN 30 DAYS AS REQUIRED BY | | 10CFR50.73(a)(2)(ii)(B)." | | | | THERE ARE TWO NITROGEN STORAGE TANKS ONSITE COMMON TO BOTH OPERATING UNITS. | | EACH TANK WAS MAINTAINED GREATER THAN THE TECH SPEC MINIMUM VOLUME OF 2500 | | GALLONS NITROGEN WHICH CORRESPONDS TO 75% CONTROL ROOM LEVEL INDICATION. | | THIS MINIMUM VOLUME ERRONEOUSLY CALCULATED AS A 7 DAY POST LOCA SUPPLY IS | | ACTUALLY ONLY A 4 DAY SUPPLY. THE LICENSEE IS ADMINISTRATIVELY MAINTAINING | | EACH TANK VOLUME GREATER THAN 3304 GALLONS WHICH CORRESPONDS TO 95% CONTROL | | ROOM LEVEL INDICATION. THIS WILL ENSURE THE REQUIRED 7 DAY SUPPLY IS MET | | UNTIL SITE ENGINEERING COMPLETES THEIR EVALUATION AND DETERMINES LONG TERM | | CORRECTIVE ACTIONS. | | | | THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR. | +------------------------------------------------------------------------------+