report on safety related occurrences and reactor trips

and Reactor Trips
STATENS KARNKRAFTINSPEKTION SWEDISH NUCLEAR POWER INSPECTORATE
REPORT ON SAFETY RELATED OCCURRENCES AND REACTOR TRIPS JANUARY - JUNE 30 1935
III
ABSTRACT
occurrences and reactor trips in Swedish nuclear power plants in
operation during the period from January 1 to June 30 1985. It is
based on the reports submitted by the utilities to the Swedish-
Nuclear Power Inspectorate accordning to Technical Specifications.
Twice a year since 1974 the Insprctorate has issued a complitation
on such reported occurrences and reactor trips. Starting with the
compliation of the second half of 1982 some new features have been
introduced. The most important change is that the volume of infor-
mation has been increased. The full text, provided by the utilities
when reporting the incidents, is now attached to the codified in-
formation and also the layout has been altered to facilitate reading.
As in the previous repnrts the occurrences and reactor trips are
arranged both alphabetically by facility name and chronologically
by report number for each facility. Electricity generation charts
for each facility are also presented.
The primary purpose of this reoort is thus to Dresent all the l-
formation furnished bv ulitities when they submit their reports
accordninq to Technical Specifications. The only evaluation made by
the Inspectorate is the categorization on the incidents.
Like the previous reports this one also presents frequency of
incidents asrelated to affected component, cause of incident etc.
The difference is that only information reported by the ulitities
is used. This is the reason why a considerable proportion of the
incidents are categorized as "other component " or "other fault".
Sometime in the future, however, the Inspectorate plans to put out
a special report contaning its own analyses of the most interesting
events along with processed statistics and other information.
IV
Contents
Page
Bl-RO-001/85 - SYSTEM 649 EL. SYSTEM FOR GAS TURBINE UITHIN STATION
GI3:1 AUTOTRIP DUE TO LOU BEARING HOUSING PRESSURE
DATE:850226 / EL.POUER 583 HUE / CATEGORY: 3
TYPE: 106 203 312 409 502 611 705 812 909
APPROX. 15 MIN. AFTER PERIODIC START TEST, A GAS TURBINE HALF, G13:l, TRIPPED DUE TO SIGNAL "HIGH BEARING HOUSING PRESSURE". THE SECOND GAS TURBINE HALF DELIVERED FULL POUER, UHEREBY THE REQUIREMENTS IN TECHNICAL SPECIFICATIONS CHAP. 3 UERE FULFILLED. GAS TURBINE HALF G13:l UAS UNAVAILABLE FROI1 0840 TO 1135 HOURS ON 1965-02-26. G13:l TRIPPED FOR THE SAME REASON AS ON 1984-06-19, SEE REPORT Bl-RO-014/84. THE CAUSE THEN UAS INTERNAL DEFORMATION OF A VENT HOSE, UHICH UAS THEN REPLACED. ON THAT OCCASION, IT UAS NOT OBSERVED THAT PIECES OF RUBBER FROM THE HOSE HAD COME LOOSE AND CONTINUED INTO THE PIPELINE TO UHICH THE HOSE CONNECTS. FINALLY, THE PIECES OF RUBBER ACCUMULATED IN A FLAME TRAP THAT TERMINATES THE PIPE. THIS BECAME CLOGGED, AND EVACUATION OF THE BEARING HOUSING CEASED. PIPE AND FLAME TRAP CLEANED. G13 HAS SINCE BEEN TEST-RUN UITH SATISFACTORY RESULTS. THE HOSES ON ALL SETS UERE PREVIOUSLY REPLACED UITH HOSES OF ANOTHER GRADE. THE PIPES AND FLAME TRAPS ON ALL SETS
UILL BE CHECKED.
DATE:850227 / EL.POUER 583 MUE / CATEGORY: 3
TYPE: 106 201 304 409 502 611 701 811
SIGNAL OBTAINED IN CENTRAL CONTROL ROOM FOR EQUIPMENT FAULT IN 551 K901 . SS14 PARTIAL CONDITION A CHANNEL UOULD NOT HAVE TRIPPED ON HIGH ACTIVITY IN STEAM LINE. THE PARTIAL CONDITION UAS UNAVAILABLE BETUEEN 0521 AND 0930 HOURS. HIGH VOLTAGE TO MONITORING EQUIPMENT LOST. INTERRUPTION IN FILTER CAPACITOR Cl (ELECTROLYTIC). THE EQUIPMENT'S HIGH-VOLTAGE SECTION UAS REPLACED UITH A RESERVE. Cl UAS REPLACED IN THE DEFECTIVE HIGH-VOLTAGE SECTION. OTHER
ELECTROLYTIC CAPACITORS IN THE CIRCUIT HAVE ALSO BEEN REPLACED.
Bl-RO-003/85 - SYSTEM 713 SALT UATER FOR NORMAL OPERATION
LEAKAGE IN 713 P7
TYPE: 106 201 302 403 503 606 703 801 EARTH FAULT UAS OBTAINED FROM AN ELECTRICAL CUBICLE DUE TO THE FACT THAT UATER SPRAYED ONTO THE CUBICLE FROM A HOLE IN THE PUMP CASING ON 713 P7. THE PUMP UAS STOPPED AND 713 P6 UAS SUITCHED IN. THE PUMP UAS REPAIRED AND UAS OPERABLE ONCE AGAIN ON 7 MARCH 1985.
2 -
SAFETY RELATED OCCURRENCS 850101 TO 850630.
REDUNDANT OBJECT SUITCHED IN. REPAIR CRITERION 7 DAYS. THE GUIDE FOR AN INNER SEAL RING CUEAR RING) IN THE PU11P CASING HAD SUFFERED SO HUCH CORROSION DAMAGE THAT THE SEAL RING HAD COME LOOSE AND UAS ROTATING UITH THE PUMP SHAFT, UHEREBY THE RING ABRADED A HOLE IN THE PUnP CASING. THE PUHP CA5ING HAS BEEN REPLACED UITH ONE UITH LESS CORRO- SION DAMAGE. THE GUIDES FOR THE SEAL RINGS HAVE BEEN STRENGTHENED UITH PLASTIC STEEL. NEU PUHP CASINGS OF CORROSION-RESISTANT MATERIAL HAVE ALREADY BEEN ORDERED FOR DELIVERY PRIOR TO THE 1985 RE- FUELLING
OUTAGE.
Bl-RO-004/85 - SYSTEM 354 HYDRAULIC SYSTEM FOR CONTROL ROD DRIVES (BUR)
REPAIR OF LEAKY VENT VALVES
TYPE: 106 201 309 409 506 605 701 812 909
INCREASING LEAKAGE TO SYSTEM 352 LED TO A DECISION TO PERFORM CORRECTIVE ACTION ON VENT VALVES IN SYSTEM 354. THE RELEVANT VALVES UERE DETERMINED VIA TEMPERATURE RE- CORDING. NO CONSEQUENCES FOR THE REACTOR TRIP FUNCTION. INCREASED LEAKAGE TO 352 BY JUST OVER 2 M 3 /H. INSUFFICIENT SPRING TENSION DUE TO A COMBINATION OF RELAXED SPRINGS AND LACK OF CLARITY IN PRETENSIONING DIRECTIONS. AS A RESULT, THE VALVES ARE LEAKING AND THE SEAT AND DISC ARE ERODING. PARTS REPLACED OR REPAIRED. IN V325, A NEU TYPE OF SPRING HAS BEEN INSTALLED THAT IS EXPECTED TO IMPROVE THE OPERATING AVAILABILITY OF THE VALVE, AS UELL AS A NEU VALVE BODY AND DISC. IN V330, A NEU SPRING, NEU VALVE BODY AND NEU DISC HAVE BEEN INSTALLED. IN V331 , THE SEAT HAS BEEN GROUND AND A NEU DISC HAS BEEN INSTALLED. IN V332, THE SEAT HAS BEEN GROUND AND A NEU DISC AND SPRING HAVE BEEN INSTALLED. THE MAINTENANCE INSTRUCTIONS UITH REGARD TO PRETENSION SETTING HAVE BEEN CLARIFIED. THE NEU SPRING UAS PRETENSIONED TO 620 KG. THE OTHERS TO 580 KG. THE VALVES UILL BE CHECKED AT THE FIRST OPPORTUNITY FOR EXPERIENCE. IT IS ESTIMATED THAT ALL SPRINGS UILL BE REPLACED UITH A NEU TYPE BY THE NEXT REFUELLING OUTAGE.
Bl-RO-005/85 - SYSTEM 312 MAIN FEED UATER SYSTEM
312 V2, MALFUNCTIONING INDICATION
TYPE: 106 203 303 409 506 605 701 801 902
IN CONNECTION UITH PERIODIC TESTING OF THE ISOLATING VALVES IN SYSTEM 312 CV3, V4), 312 V2 INDICATED OPEN EVEN UHEN THE VALVE UAS SUPPOSED TO BE CLOSED. 312 V4, UHICH IS CONNECTED IN SERIES UITH 312 V2, UAS CLOSED AND THE SPACE BETUEEN THE ISOLATING VALVES UAS DRAINED. IT UAS THEREBY POSSIBLE TOOBSERVE THAT 312 V2 UAS TIGHT AND THEREFORE MUST BE CLOSED, DESPITE THE FACT THAT THE INDICATION SHOWED OPEN. THE VALVE UAS THEREFORE REGARDED AS OPERABLE. THE INDICATION PICTURE IN THE CONTROL ROOM IS INCORRECT. CHECK OF THE INDICATING UNIT REVEALED SLUGGISHNESS IN THE POTENTIOMETER BEARING.
3 -
THE INDICATING UNIT UAS REPLACED UITH AN IDENTICAL UNIT DURING THE 1985 REFUELLING OUTAGE. A NEU TYPE OF INDICATING UNIT 15 CURRENTLY BEING TESTED ON ISOLATING VALUE 321 V24 . IF THE RESULTS UITH THIS UNIT ARE GOOD, UE UILL REPLACE THE INDICATING UNIT ON 312 U2 AS UELL .
Bl-RO-006/85 - SYSTEM 322 CONTAINMENT SPRAY SYSTEM
322 P3, MALFUNCTIONING ALC BREAKER
TYPE: 106 201 304 409 504 609 704 812 909
UHEN AN ATTEMPT UAS MADE TO STOP 322 P3 AT 0015 HOURS, THE BREAKER FAILED TO OPEN, SO THE PUMP UAS KEPT IN SERVICE. AT 0638 HOURS, 322 P2 UAS RENDERED OPERABLE AS A RESERVE FOR P3, AND REPAIR OF P3 UAS CARRIED OUT. 322 P3 UAS OKCE AGAIN OPERABLE AT 1012 HOURS. NO CONSEQUENCES. 322 P3 UAS INOPERABLE FOR 10 HOURS, 322 P2 UAS ON RESERVE DURING THIS TIME. TOO LITTLE TOLERANCE FOR THE TRIP DETENT, SO THAT THE PAUL FAILED TO RELEASE THE TRIP ARM. TOLERANCE ARM ADJUSTED TO CORRECT DIMENSION.THE BREAKER IS INCLUDED
IN THE GROUP OF BREAKERS THAT ARE SCHEDULED TO BE REPLACED DURING THE REFUELLING OUTAGE UITH ALG BREAKERS.
Bl-RO-007/85 - SYSTEM 312 MAIN FEED UATER SYSTEM
ACTUATOR FAULT
TYPE: 106 201 304 409 504 608 703 812 902
Bl-RO-008/85 - SYSTEM 675 CONTINUES VOLTAGE 110 V NET
EARTH FAULT
TYPE: 106 201 302 409 502 609 701 809 909
SIGNAL FOR EARTH FAULT UAS OBTAINED ON BUSBAR 675 Bl. NO DIRECT EFFECT. THE EARTH FAULT UAS TRACED TO THE SLIP CLUTCH FOR CONTROL ROD DRIVE D13. CONTROL ROD DRIVE D13 UAS SERVICED DURING THE 1985 REFUELLING OUTAGE. IT UAS THEN DISCOVERED THAT THE MICROSUITCH IN THE SLIP CLUTCH CONTAINED MOISTURE, UHICH HAD CAUSED THE EARTH FAULT. THE MOISTURE PROBABLY STEMMED FROM THE LEAKAGE THAT UAS DISCOVERED FROM THE MAIN LINE IN SYSTEM 353 UNDER THE CONTROL ROD DRIVES. DURING THE TIME FROM DISCOVERY TO THE REFUELLING OUTAGE, THE EARTH FAULT UAS ELIMINATED BY CONNECTION OF THE EARTH FAULT TREATMENT DEVICE. THE MOISTURE-DAMAGED MICROSUITCH UAS REPLACED DURING THE 1965 REFUELLING OUTAGE.
- 4 -
Bl-RO-009/65 - SYSTEM 661 STANDBY DIESEL SYSTEM DIESELSET
HIGH LUBE OIL TEMPERATURE, DIESEL B, DURING PERIODIC TEST
DATE.850616 / EL.POUER 466 HUE / CATEGORY: 3
TYPE: 106 203 301 409 502 602 705 812 909
DURING PERIODIC TESTING OF 661 G2 CDIESEL B) ALARI1 UAS OBTAINED FOR HIGH LUBE OIL TEJ1P. AFTER ABOUT 25 MINS. OF OPERATION AT FULL POUER. AT 1000 HOURS, 661 G2 UAS SHUT DOUN FOR CLEANING OF THE SALT UATER COOLER. OPERABLE ONCE AGAIN ON 17/6 AT 0200 HOURS. 661 G2 UNAVAILABLE FOR 16 HOURS. 661 Gl AND GAS TURBINES TESTRUN UITH SATISFACTORY RESULTS DURING THE OUTAGE. SALT UATER COOLER PARTIALLY CLOGGED UITH A MIXTURE OF SLUDGE AND IRON SULPHATE.
COOLER CLEANED.
TYPE: 106 209 304 409 504 609 701 805 909
UHEN MANUAL TRIP UAS INITIATED AT 1156 HOURS, THE BREAKER FAILED TO OPEN. THE PUMP UAS KEPT IN SERVICE UNTIL REPAIR PERSONNEL UERE ABLE TO TRIP AND REPLACE THE BREAKER. 322 P3 ONCE AGAIN OPERABLE AT 1037 HOURS THE NEXT DAY. NO CONSEQUENCES. 322 P3 UAS INOPERABLE FOR 21 HOURS. 322 P2 UAS ON STANDBY DURING THE PERIOD. UEAR IN LINK ARM JOINT IN DISCONNECT MECHANISM, CAUSING BINDING IN CERTAIN SITUATIONS. BREAKER REPLACED UITH RENOVATED BREAKER. THE BREAKER IS INCLUDED IN THE GROUP OF BREAKERS SCHEDULED TO BE REPLACED DURING THE 1985
REFUELLING OUTAGE UITH ALG BREAKERS.
Bl-RO-011/85 - SYSTEM 322 CONTAINMENT SPRAY SYSTEM
322 93 INCORRECTLY DISCONNECTED
TYPE: 106 209 409 503 606 707 812 909
THE MECHANICAL MAINTENANCE DEPARTMENT HAD EXPRESSED A DESIRE TO KEEP THE RUNNING TIME DOUN ON 322 P3 SINCE THIS PUMP HAD A SLIGHTLY HIGHER VIBRATION LEVEL THAN OTHERS. 322 P2 UAS THEN PUT IN AS A REPLACEMENT AND 322 P3 UAS DISCONNECTED IN THE SUITCHGEAR OH 1985-06-19 AT 1100 HOURS. DUE TO OVERSIGHT OF THE FACT THAT 322 PI AND 322 P2 ARE FED FROM THE SAME MAIN SUB, THE CRITERIA ACCORDING TO TECHNICAL SPECIFICATIONS 3.8 C UERE NOT FULFILLED. CIRCUIT 2 UITH 322 P3 UAS THEREBY UNAVAILABLE FOR A PERIOD OF 22 HOURS. MISINTERPRETATION OF TECHNICAL SPECIFICATIONS. 322 P3 RECONNECTED IN SUITCHGEAR ON 1985-06-20 AT 0900 HOURS.
- 5 -
Bl-RO-012/85 - SYSTEM 221 FULL LENGTH CONTROL ROD DRIVES
DISABLED CONTROL ROD
TYPE: 106 203 304 409 502 608 707 812 901
IN CONNECTION UITH RECURRENT 5* CONTROL ROD DRIVE TESTING ON 1985-06-23 AT 0200 HOURS, IT UA5 NOTED THAT CONTROL ROD C U COULD NOT BE OPERATED. LIKE OTHER CONTROL RODS, Cl1 IS IN THE FULLY UITHDRAUN POSITION C1005O. THE FAULT AROSE UHEN THE EARTH FAULT TREATMENT DEVICE UAS CONNECTED TO THE SLIP CLUTCH FOR CONTROL D13 ON 14 JUNE 1985, BUT UAS NOT DISCOVERED UNTIL THE CONTROL ROD TEST. Cl1 HAS NOT BEEN ELECTRICALLY OPERABLE DURING THE PERIOD 14 JUNE - 25 JUNE 1985. NONE. THE SHUTDOUN MARGIN HAS BEEN FOUND TO BE 4.4% UITH Cll AND THE HOST UORTHY NEARBY CONTROL ROD COMPLETELY UITH-DRAUN. THE UIRING TABLE FOR THE 110V FEED TO THE OPERATION OF Cll UAS INCORRECT, AS A RESULT OF UHICH UHEN THE MINIATURE CIRCUIT BREAKER THAT FEEDS Cll AND 13 UAS REPLACED UITH THE EARTH FAULT TREATMENT DEVICE, THE ACTUATING RELAYS FOR Cll DID NOT RECEIVE ANY POUER. UITH THE MINIATURE CIRCUIT BREAKER CONNECTED NORMALLY, THE MANOEUVRE UORKED AS INTENDED. CORRECTIVE ACTION TAKEN. INCORRECT UIRING REMOVED AND REUTRED SO THAT A CORRECT CONTROL VOLTAGE IS OBTAINED. CORRECTIVE ACTION PLANNED EXAMINATION OF CORRESPONDING UIRING TABLES FOR BARSEB<CK UNITS 1 AND 2 IN ORDER TO DETERMINE UHETHER THERE IS ANY SYSTEMATIC ERROR IN THE ELECTRICAL DESIGN FOR CONTROL ROD OPERATION.
B2-RO-001/85 - SYSTEM 675 CONTINUES VOLTAGE 110 V NET
EARTH FAULT
TYPE: 106 201 301 409 503 605
ON 1985-02-16 AT 0630 HOURS, ALARM UAS OBTAINED FROM 675 K058 "EARTH FAULT 675 Bl". FAULT TRACIN'J UAS COMMENCED AND THE FAULT UAS TRACED TO VALVE V41 IN SYSTEM 314. THE EARTH FAULT TREATMENT DEVICE UAS CONNECTED AT 0815 HOURS. THE INDICATION FOR V41 HAS BEEN JUMPERED
OUT. V41 IS A VACUUM VALVE THAT ADMITS NITROGEN GAS TO THE BLOUDOUN PIPES UHEN A VACUUM PRESSURE ARISES IN THEM. REDUCED INSULATION VALUE FOR 675 Bl FOR 1 H AND 45 MIN. UNKNOUN AT THE PRESENT TIME. COLD SHUTDOUN IS REQUIRED TO INVESTIGATE THE CAUSE OF THE FAULT.
- 6 -
B2-RO-002/85 - SYSTEM 351 BORON INJECTION SYSTEM CBUR)
LOU BORON CONCENTRATION AFTER PERIODIC TEST
TYPE: 106 203 301 409 502 605 704 812 901
AFTER PERIODIC TESTING OF THE BORON SYSTEM, IT UAS FOUND THAT ABOUT 1/3 OF THE TANK CONTENTS IN 351 TI UERE GONE. THE BORON SOLUTION RAN OUT VIA V27 TO SYSTEM 345 CUASTE COLLECTION). IT UAS FOUND THAT 351 U27 CAN BE OPENED 1.5 TURNS AFTER LOCK. THE TANK UAS REFILLED AND BORON UAS ADDED TO THE RIGHT CON- CENTRATION. THIS UAS FINISHED UITHIN FOUR HOURS. THE VALUE UILL BE CHECKED SPECIALLY PRIOR TO TESTING. REPLACEMENT UITH A BALL VALVE IS BEING CONSIDERED.
B2-RO-003/85 - SYSTEM 312 flAIN FEED UATER SYSTEM
FAILURE TO CLOSE DURING TEST
TYPE: 106 203 304 409 502 605 701 812 909
UHEN THE HIGH-PRESSURE PREHEATER BYPASS IS TESTED AT REDUCED POUER, 312 V14 IS SUPPOSED TO CLOSE. UPON MANUAL "CLOSE" ORDER, THE VALVE LEFT THE OPEN POSITION, ONLY TO OPEN AGAIN IMMEDIATELY AUTOMATICALLY. NO CONSEQUENCES FOR NORMAL OPERATION. IN THE EVENT OF AN ACCIDENT, THE AUTOMATIC FLOU LIMITATION FOR STRING 2 UOULD HAVE BEEN OUT OF ORDER. IT IS IMPOSSIBLE TO SAY UHEN THE FAULT AROSE, BUT AUTOMATIC FLOU LIMITATION UAS ONCE AGAIN OPERABLE ON 1985-04-15 AT 0530 HOURS. COMPONENT FAULT IN ELECTRONICS CIRCUIT BOARD QE27. FAULT TRACING UAS CARRIED OUT IMMEDIATELY AND ELECTRONICS CIRCUIT BOARD QE27 UAS REPLACED. FUNCTIONAL TESTING UAS CARRIED OUT AFTER THE CORRECTIVE ACTION UITH SATISFACTORY RESULTS.
B2-RO-004/85 - SYSTEM 322 CONTAINMENT SPRAY SYSTEM
BLOCKED AUTO-OPEN CONDITION FOR V1-V2
DATE .-850413 / EL . POUER 300 MUE / CATEGORY: 3
TYPE: 106 208 312 409 506 611 707 812 906
UHEN ELECTRICAL CUBICLE RE14 UAS OPENED FOR CORRECTION OF ANOTHER FAULT, IT UAS DISCOVERED THAT A BRIDGE HAD BEEN ESTABLISHED FROM TERMINAL RE14.D18.140.3 TO TERMINALSRE14.D18.340.1 AND 2 MARKED OPERATING ORDER 940. A CHECK REVEALED THAT OPERATING ORDER 940 HAD BEEN CONCLUDED ON 1985-02-20. THE BRIDGE UAS REMOVED. SUCH A BRIDGE IS MADE IN CONNECTION UITH THE LIFT OF A FUEL TRANSPORT CASK AND INTERRUPTS THE CONTINUOUS "OPEN" SIGNAL TO 322 VI AND V2, UHILE V3'S AUTO-OPEN SIGNAL IS NOT AFFECTED. THE MEASURE IS PERFORMED TO PERMIT MANUAL CLOSURE OF VI AND/OR V2 IN THE EVENT OF AN ACCIDENT DURING THE LIFT OF THE TRANSPORT CASK. THE BLOCKAGE OF THE AUTO-OPEN CONDITION FOR VI AND V2 ALLOUED THE POSSIBILITY OF CLOSING THE VALVES MANUALLY. NO AUTOMATIC CONDITIONS FOR THE SYSTEM UERE AFFECTED.
7 -
THE BLOCKAGE OF THE AUTO-OPEN CONDITION UA5 CARRIED OUT IN ACCORDANCE UITH THE OPERATING ORDER AT THE SUBORDER OF THE LIFT LEADER, UHILE THE CORRESPONDING SUBORDER UPON CONCLUDED LIFT UAS NOT SPECIFIED. AN OPERATING ORDER OR THE LIKE THAT 5PECIFTES SOME TYPE OF OPERATIONAL REARRANGEMENT SHALL BE SUPPLEMENTED UITH A RESTORATION ORDER AFTER CHECKING OF ALL COMPLETED MEASURES HAS BEEN CARRIED OUT.
B2-RO-005/85 - SYSTEM 847 EL FIRE PROTECTION SYSTEM
BLOCKAGE OF FIRE ALARM DETECTORS
DATE:850422 / EL.POUER 575 HUE / CATE3RY: 3
TYPE: 106 208 312 409 502 611 707 812 909
IN CONNECTION UITH INSTALLATION OF THE FIRE ALARM SYSTEM IN THE NEU SERVICE BUILDING, SOME REALLOCATION OF DETECTORS TO SECTIONS HAS BEEN DONE. DETECTORS IN 2^0305 HAVE BEEN SEPARATED FROM SECTION 156 AND CONNECTED TO SECTION 150. THE UORK, UHICH UAS CARRIED OUT ON 1985-04-22 BETUEEN 1200 AND 1600 HOURS, UAS DONE UITHOUT A UORK NOTICE, BUT UITH BLOCKED ALARM SECTIONS. SECTIONS 150 AND 156 UERE UNAVAILABLE FOR ABOUT 2 HOURS EACH. 1) THE UORK UAS BEGUN IN AN OPERATIONAL SUBSYSTEM PART UITHOUT A UORK NOTICE. 2) ALARM SECTIONS UERE SHUT OFF UITHOUT A DISPENSATION.
THIS IMPROPER PROCEDURE HAS BEEN POINTED OUT TO THOSE INVOLVED. TOTAL DOUNTIME: SECTION 150 2 H " 156 2 H
B2-RO-006/85 - SYSTEM 321 RESIDUAL HEAT REMOVAL SYSTEM
321 PI TRIPPED ON OVERCURRENT, LEAKAGE IN CABLE ENTRY
TYPE: 106 201 301 409 503 606 702 810 901
ON 1985-05-05 AT 1904 HOURS, 321 PI TRIPPED ON OVERCURRENT. ON THIS OCCASION, ALARM UAS OBTAINED FOR LOST 734 FLOU. INSPECTION OF THE PUMP REVEALED UATER AND STEAM LEAKAGE FROM THE PUMP. 321 PI UAS SHUT OFF AND ISOLATED, AND IN CONNECTION HEREUITH THE Y22 AND Y12 CONDITIONS FOR ROOM MONITORING IN THE PUMP SPACE UERE BLOCKED. THE ENTIRE 321 SYSTEM HAD TO BE ISOLATED IN ORDER THAT PI COULD BE ISOLATED. P2 UAS RESTARTED AT 2027 HOURS. PROBABLY SHORT CIRCUIT IN A CABLE ENTRY DUE TO AGING Cfi MANUFACTURING DEFECT. NEU DESIGN UILL BE INTRODUCED GRADUALLY ON THE PUMP MOTORS. IT CONSISTS OF UJING TEF2EL-INSULATED UINDING CABLE THROUGHOUT UITH DOUBLE STUFFING BOX.
- 8 -
B2-RO-007/85 - SYSTEM 713 SALT UATER FOR NORMAL OPERATION
LEAKAGE IN SHAFT SEAL
TYPE: 106 202 309 409 503 606 701 801 909
ABNORI1AL LEAKAGE HAS BEEN NOTICED FROM A SHAFT SEAL ON OPERATING ROUNDS. A UORK NOTICE UAS ESTABLISHED ON 1985-05-06 AT 0200 HOURS FOR REPLACEMENT OF SHAFT SEAL. NONE. REPLACEMENT OF MECHANICAL SEAL UITH NEU TYPE. PUMP TESTED AND IN
SERVICE ONCE AGAIN ON 1985-05-08 AT 1330 HOURS.
B2-RO-008/85 - SYSTEM 743 VENTILATION SYSTEM FOR OTHER BUILDINGS
DAMPER FAILS TO CLOSE DURING TEST
TYPE: 106 203 304 409 503 605 705 812 909 TURING PERIODIC TESTING OF 743, DAMPER 743 ST1A FAILED TO CLOSE COMPLETELY. THE MALFUNCTION UAS REPORTED. FUNCTION RESTORED AND TESTED ON 85-05-03 AT 0855 HOURS. EMERGENCY VENTILATION INOPERABLE. INSPECTION REVEALED THAT THE DAMPER'S RUBBER SEALING STRIP UAS DRIED-OUT. AS A RESULT, THE DAMPER MOTOR UAS UNABLE TO CLOSE THE DAMPER. GREASING OF THE RUBBER SEALING STRIP UITH SILICONE GREASE AND GREASINC OF LINK ARMS. THE CORRESPONDING DAMPER UILL BE INSPECTED ON UNIT 1.
B2-RO-309/85 - SYSTEM 681 CONTROL EQUIPMENT FOR AUXILIARY ELECTRIC SYST
EMS
TYPE: 105 201 301 409 501 611 702 812 909
AUTOMATIC START SEQUENCE SYSTEM 681 DISCONNECTED ON 85-05-28 BETUEEN 1112 AND 1144 HOURS FOR REPLACEMENT OF DEFECTIVE RELAY. NONE. UNKNOWN. RELAY REPLACED
- 9 -
B2-RO-010/85 - SYSTEM 765 UATER FOR FIRE PROTECTION
LEAKAGE IN BREAST SEAL
TYPE: 106 202 309 409 502 605 701 804 904
IN CONNECTION UITH AN OPERATING ROUND, LEAKAGE UAS DISCOVERED FROH 765 V991. FOR CORRECTIVE ACTION, THE MAIN LINE UAS DRAINED AND THE O-RING SEAL IN THE BREAST UAS REPLACED. THE LINE TO THE TURBINE AND ELECTRICAL BUILDING UAS OUT OF SERVICE BETUEEN 1530 AND 1730 HOURS ON 85-06-28. UHILF. UORK ON THE VALVE UAS IN PROGRESS, THE CONNECTION FOR 765 V991 UAS PLUGGED, AND THE 5YSTEM COULD HAVE BEEN FILLED UP AT ANY TIME DURING THE UORK, IF NECESSARY. THE VALVE BREAST UAS, IN ALL PROBABILITY, FITTED INCORRECTLY, CAUSING THE PACKING TO BE PINCHED. CJHEN THE SYSTEM UAS FILLED UP, A SMALL PRESSURE SURGE LED TO THE LEAKAGE. O-RING SEAL REPLACED.
Fl-RO-001/85 - SYSTEM 651 STANDBY DIESEL SYSTEM DIESELSET
DIESEL SHUTDOUN DUE TO LEAKAGE IN LT CIRCUIT
TYPE: 106 201 301 409 506 602 701 801 903
THE DILUTION FEED REQUIREMENT HAS GRADUALLY INCREASED IN THE LT CIRCUIT FOR DG130. SINCE FILLING TENDED TO BE REQUIRED ON EVERY SHIFT, IT UAS DECIDED THAT THE DIESEL'S AUTOMATIC FUNCTION UAS JEOPARDIZED. THE DIESEL UAS SHUT DOUN FOR CORRECTIVE ACTION ON 850114 AT 1100 HOURS AFTER OTHER DIESELS AND OBJECTS HAD BEEN TESTED IN ACCORDANCE UITH THE TECHNICAL SPECIFICATIONS. OUTAGE LIMIT 7 DAYS ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.10. LEAKAGE FROM THE LP CIRCUIT TO THE SALT UATER SIDE DUE TO LEAKAGE IN SHELL RING ON END OF HEAT EXCHANGER CAUSED BYCORROSION. SINCE THE CORROSION UAS ONLY LOCATED ON THE CIRCUMFERENCE, NO FAULT UAS DISCOVERED IN CONNECTION UITH CLEANING OF COOLERS DURING THE 1934 REFUELLING OUTAGE. PROBABLY FLAU IN SURFACE COATING OR DAMAGE DURING INSTALLATION, 652 P73, UHICH TRIPPED UHEN DG130 STOPPED, UA5 FOUND AFTER TRIAL OPERATION TO HAVE A BREAK IN ITS MOTOR UINDING. INTERMEDIATE RING REPLACED. CIRCULATION CIRCUIT STARTED AND DIESEL READY FOR START AT 2130 HOURS. AFTER UARMING-UP, THE DIESEL UAS TEST-RUN AT 0145 HOURS UITH SATISFACTORY RESULTS. HOUEVER, CIRCULATING PUMP 652 P73 TRIPPED ON SHUTDOUN OF DIESEL. ON 850115 AT 12 O'CLOCK, THE DIESEL UAS SHUT DOUN ONCE AGAIN FOR REPLACEMENT OF P73. PUMP UNIT REPLACED AND DIESEL ONCE AGAIN READY TO START AT 1400 HOURS. DG130 TEST-RUN ONCE AGAIN ON 850115 AT 1530 HOURS UITH SATISFACTORY RESULTS. (TOTAL DOUNTIME 13 H.>
10
F1-RO-0P2/85 - SVSTEH 170 COOLING UATER PLANT
TEMPERATURE MONITORING OF INCOHING COOLANT CUT OF ORDER IN CONNECTION UITH EJ1PTIED STRAINER STRING
TYPE: 206 202 302 409 504 611 70? 812 909
ON 1985-01-31 AT 1500 HOURS, IT UAS DISCOVERED THAT 170 K502/K503 UAS 5H0UING AN UNREASONABLY HIGH INLET TEMPERATURE IN THE COOLANT CHANNEL. A CHECK REVEALED THAT 170 K503 (JAS CONNECTED, UHICH IS nOUNTED IN STRAINER STRING 2, UHICH UAS EMPTIED FOR UORK. ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.8 E5, RUNBACK TO COLD SHUTDOUN REACTOR SHALL TAKE PLACE. UHEN STRAINER STRING 2 UAS EMPTIED OK 1985-0 1-16, THE TEMPERATURE SENSOR IN THE INLET UAS NOT SUITCHED. SUITCHING CARRIED OUT TO TEMPERATURE SENSOR K502. CTOTAL DOUNTII1E 15
DAYS.)
LEVEL MONITORING IN SURGE SHAFT OUT OF ORDER
TYPE: 106 201 302 409 503 611 706 812 909
ON 1985-02-03, AT 1300 HOURS, IT UAS DISCOVERED THAT 172 K401 UAS SHOUING AN UNREASONABLY STABLE VALUE ON THE RECORDING INSTRUMENT IN THE CONTROL ROOM. JUDGING FROM THE RECORDING CHART, LEVEL MONITORING HAD NOT BEEN FUNCTIONING FOR THE PAST 24 HOURS. ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.8 E5, RUNBACK TO COLD SHUTDOUN REACTOR SHALL TAKE PLACE. SEIZURE DUE TO UNUSUALLY HEAVY SNOUFALL. LEVEL SENSOR EXERCISED VIA UIRE ROPE, AFTER UHICH IT FUNCTIONED NORMALLY ONCE AGAIN. CTOTAL DOUNTIME ABOUT 36 H.)
Fl-RO-004/85 - SYSTEM 651 STANDBY DIESEL SYSTEM DIESELSET
SHUTDOUN DUE TO LEAKAGE IN HIGH-TEMPERATURE CIRCUIT
TYPE: 106 201 301 409 506 611 701 805 905
INCREASED MAKE-UP FEED NEED IN HIGH-TEMPERATURE CIRCUIT. LEAK TRACING REVEALED LEAKAGE IN PIPE COUPLING IN INTERNAL COOLANT PIPE FROM ENGINE BLOCK TO TURBO-GENERATOR SET. THE LEAKAGE UAS GREATER SINCE THE DIESEL AND THEREBY THE CIRCULATING PUMP FOR THE HIGH-TEMPERATURE CIRCUIT UERE IN OPERATION. THERE IS A RISK THAT FURTHER DEGRADATION COULD JEOPARDIZE THE DIESEL'S AUTOMATIC CONTROL FUNCTION. THE DIESEL UAS SHUT DOUN FOR CORRECTIVE ACTION ON 85-02-05 AT 1100 HOURS AFTER OTHER DIESELS AND OBJECTS HAD BE^N TESTED IN ACCORDANCE UITH THE TECHNICAL SPECIFICATIONS. OUTAGE LIMIT SEVEN DAYS ACCORDING TO TECHNICAL SPECIFICA- TIONS, CHAP. 3.10. CONCERNED PIPE SECTION UITH PIPE COUPLING DISCONNECTED, CLEANED AND CHECKED. PIPES AND FITTINGS INCL. SEALING SURFACES IN SATISFACTORY
11 -
CONDITION. THE PIPE COUPLING CONTAINS AN O-RING AS A SEALING ELEMENT. THE O-RING EXHIBITED NO SURFACE DAriAGES, BUT THE CROSS SECTION UAS DEFORMED ON PART OF THE CIRCUMFERENCE. THE O-RING HAS THEREBY PROBABLY LOST ITS SEALING CAPACITY. COMBINATION OF EXCESSIVE TIGHTENING FORCE AND II1PROPER SEATING OF THE O-RING IS THE PROBABLE PRII1ARY CAUSE. CONCERNED O-RING REPLACED. OVERHAUL OF THE TURBO-GENERATOR SET FOR ALL DIESEL SETS IN Fl IS SCHEDULED FOR THE 1985 REFUELLING OUTAGE, INCLUDING REPLACEMENT OF CONCERNED O-RINGS. THE DIESEL UAS TEST-RUN AT 1730 HOURS, UHEREBY START BLOCKING UAS OBTAINED. THE CAUSE UAS TRACED TO A MIRROR RELAY FOR FAULT INDICATION, UHICH UAS RESTORFD. DIESEL TEST-RUN UITH SATISFACTORY RESULTS AND OPERABLE AT 1930 HOURS, TOTAL DOUNTiriE 8.5 HOURS.
Fl-RO-005/65 - SYSTEM 655 STANDBY BATTERY SYSTEM, INVERTERS AND
BATTERIES
DAT£:850213 / EL.POUER 909 HUE / CATEGORY: 3
TYPE: 106 201 302 409 502 608 701 812 909 UHEN LARGE VOLTAGE SUINGS UERE FOUND ON BUSBAR LHC141, CONVERTER 0R14 UAS STOPPED FOR FAULT TRACING. AFTER A HALF HOUR OF FAULT TRACING UITHOUT RESULT, OR14 UAS SYNCHRONIZED AGAIN. AFTER ABOUT 1.5 HOURS OF
OPERATION, THE VOLTAGE SUINGS BEGAN AGAIN AND OR14 UAS STOPPED. AFTER ABOUT 4 HOURS, THE FAULT UAS FOUND AND 0R14 UAS SYNCHRONIZED. DURING THE TIME OR14 UAS OUT OF SERVICE, VOLTAGE FEED TO THE BATTERY-BACKED MAINS UAS GUARANTEED BY THE FACT THE DG140 UAS SYNCHRONIZED, ACCORDING TO TECHNICAL SPECIFICATIONS 3.10 A5. OUTAGE LIMIT 2 DAYS ACCORDING TO TECHNICAL SPECIFICATIONS, CHAP. 3.10 A5. INTERNAL VOLTAGE FEED IN SPEED GOVERNOR BOARD QALB214 HAD TOO LOU OUTPUT VOLTAGE, SHOULD BE + 15 VOLTS BUT UAS + 11 VOLTS. REPLACEMENT OF CIRCUIT BOARD QAL214. CREPAIR TIME 4 H).
Fl-RO-006/85 - SYSTEM 555 STANDBY BATTERY SYSTEM, INVERTERS AND
BATTERIES
AUTOMATIC CHANGEOVER FOR BUSBAR AHC13 ACTIVATED
TYPE: 106 201 302 407 502 609 706 812 909 DURING SECONDARY TESTING OF THE PROTECTIVE RELAYS FOR CONVERTER 0R13, THE AUTOMATIC CHANGEOVER FOR BUSBAR AHC13 ACTIVATED. CTHE TEST SHALL BE CARRIED OUT ONCE A YEAR ACCORDING TO THE TECHNICAL SPECIFICATIONS.) OUTAGE LIMIT 2 DAYS ACCORDING TO TECHNICAL SPECIFICATIONS, CHAP. 3.10 A5. POOH DESIGN OF TEST OUTLET FOR VOLTAGE SENSING PROTECTION FOR AHC13. 0R13 RESTARTED AND IN SERVICE ONCE AGAIN AT 1063 HOURS. SECONDARY TESTING OF THE VOLTAGE SENSING PROTECTIONS HAS BEEN INTERRUPTED AND POSTPONED UNTIL THE J S>35 REFUELLINGOUTAGE. THE TEST OUTLETS UILL BE REDESIGNED AT THE 1985 REFUELLING OUTAGE. CDOUNTIME 10 MIN.).
- 12 -
LARGE SUINGS IN PULSE FREQUENCY
TYPE: 106 201 301 409 502 611 702 809 901
ALARM VIA SIGNAL SEQUENCE RECORDER FOR 531 K963 H3. LARGE SUINGS IN PULSE FREQUENCY UITH A FACTOR OF ABOUT 10 UERE NOTED ON THE RECORDER CHART. THE E CHAIN IS CONNECTED AND OPERABLE, SO POUER OPERATION HAY CONTINUE ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.1 B2. ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.1 D2, THE OUTAGE LIMIT IS 30 DAYS. THE E CHAIN IS CONNECTED AND OPERABLE, SO POUER OPERATION HAY CONTINUE ACCORDING TO TECHNICAL SPECIFICATIONS, CHAP. 3.1 B2. ACCORDING TO TECHNICAL SPECIFICATIONS, CHAP. 3.1 D2, THE OUTAGE LII1IT
IS 30 DAYS. UHEN THE UIRING BETUEEN THE DETECTOR CONNECTOR AND THE OUTSIDE OF THE CONTAINMENT PENETRATION UAS DISCONNECTED, THE DISTURBANCE CEASED. JUDGING FROM PREVIOUS EXPERIENCE, THE MALFUNCTION IS LOCATED INSIDE THE COAXIAL MODULE FOR THE SRM PENETRATION 692 P101. CEARTH FAULT DUE TO LEAKAGE CURRENTS INSIDE THE COAXIAL MODULE BETUEEN THE EMBEDDED INTERNAL CONNECTOR AND THE SHIELD.) IN CONNECTION UITH OUTAGE ON 85-02-25, THE SRM CHANNEL'S CONTAINMENT PENETRATION UAS MOVED TO A SPARE POSITION,UHEREBY THE SICHAL OBTAINED THE RIGHT FUNCTION. A CHECK UAS CARRIED OUT. THE SRM CHANNEL UAS ONCE AGAIN OPERABLE ON 85-02-26 AT 0300 HOURS. A PLANT MODIFICATION IS BEING CARRIED OUT UHERE THE CONTAIN- MENT PENETRATION'S SRM MODULE IS BEING REPLACED UITH A NEU MAKE UITH A CONTINUOUS CABLE UITHOUT INTERNAL CONNECTORS, UHICH UOULD ELIMINATE THIS FAILURE MODE. REPLACEMENT UILL BE CARRIED OUT SUCCESSIVELY AND IS PLANNED TO BEGIN DURING THE 1985 REFUELLING OUTAGE.
Fl-RO-008/85 - SYSTEM 314 PRESSURE RELIEF SYSTEM
314 V22 TRIPS ON SUITCHGEAR FAULT
DATE:850225 / EL.POUER - / CATEGORY: 3
TYPE: 103 201 301 409 503 605 701 610 909
IN CONNECTION UITH CONSTANT PRESSURE CONTROL, 314 U22 TRIPPED ON SUITCHGEAR FAULT. FUSE FAILURE UAS ESTABLISHED. CONTINUED PRESSURE CONTROL UITH 331 AND 314 V21 IN AUTO MODE. SUITCHGEAR FAULT UAS OBTAINED REPEATEDLY UHEN 314 V22 UAS OPERATED. ACCORDING TO TECHNICAL SPECIFICATIONS, CHAP. 3.8 A, THE REACTOR MAY BE KEPT IN ITS OPERATING MODE FOR NO MORE THAN 7 DAYS IF ONLY ONE PRESSURE CONTROL VALVE IS OPERABLE. CIRCUIT BOARD FUNCTION UITH PURPOSE OF LIMITING MOTOR START FREQUENCY CMAX. 14 STARTS/MIN.) DEFECTIVE. THIS HAS DEGRADED THE MOTOR UINDINCS, CAUSING A BREAK IN A MOTOR UINDING. THE MAGNETIC BRAKE UAS FOUND TO GIVE NORMAL FUNCTION. VALVE DISC AND GEARBOX VERIFIED TO RUN FREELY. FAULT TRACING AND REPLACEMENT OF ELECTRONIC CIRCUIT BOARD CARRIED OUT. ELECTRIC MOTOR AND MAGNETIC BRAKE REPLACED. AFTER SUPPLEMENTARY CORRECTION OF AN INSULATION FAULT IN THE MOTOR'S JUNCTION BOX, THE ELECTRONICS UERE TRIMMED, AFTER UHICH THE VALVE UAS TEST-RUN UITH
13 -
SAFETY RELATED OCCURRENCE 850101 TO 850630.
SATISFACTORY RESULTS AT 0200 HOURS ON 85-02-27 CTOTAL DOWNTIME 31 H).
Fl-RO-009/65 - SYSTEM 221 FULL LENGTH CONTROL ROD DRIVES
TRIPPED TORQUE LIMITER AND HIGH MEASURED POUER CONSUMPTION
TYPE: 104 201 301 409 504 611 70 1 612 909
IN CONNECTION UITH UITHDRAUAL OF 221K35 IN ACCORDANCE UITH THE CONTROL ROD SEQUENCE, THE CONTROL ROD DRIVE TRIPPED IN THE 94k POSITION. UPON RENEWED UITHDRAUAL, THE DRIVE TRIPPED ONCE AGAIN. AFTER A SHORT TIME, THE DRIVE COULD ONCE AGAIN BE OPERATED. IN ALL CASES, THE FAULT UAS RESTORED AT THE DESK UITHOUT THE NECESSITY OF LOCAL RESETTING OF THE OVER- CURRENT PROTECTION, UHICH MEANS THAT THE RELEASING PRIMARY CONDITION IS THE TORQUE CLUTCH. THE POUER MEASUREMENT EQUIP- MENT UAS CONNECTED DIRECTLY AND THE FOLLOUING OBSERVATIONS UERE MADE: - DIRECTLY AFTER ENERGIZING, NORMAL POUER UAS OBTAINED C0.5 KU) , UHICH INCREASED UITH INCREASING RUNNING TIME UP TO 1.5 KU. - UPON REVERSING OR IMMEDIATE RESTART, THE HIGH POUER LEVEL UAS PRESERVED. - AFTER A CERTAIN UAITING PERIOD, THE DRIVE RESTARTED AT THE NORMAL POUER LEVEL, ONLY TO INCREASE. - SAME BEHAVIOUR DURING INSERTION AND UITHDRAUAL. - IN ORDER TO INCREASE THE THROUGHFLOU, PARTIAL SCRAM FOR THE CONCERNED GROUP UAS ACTIVATED. - NO TENDENCY TOWARDS LOUER POUER CONSUMPTION COULD BE OBSERVED AFTER A NUMBER OF MANIPULATIONS. INFORMATION ON SIMULTANEOUS TORQUE CLUTCH TRIP AND HIGH POUER CONSUMPTION RULES OUT THE POSSIBILITY OF SPURIOUS TRIP. TRIPPED TORQUE CLUTCH INDICATES THAT A HIGH TORQUE IS BEING TRANSMITTED VIA THE CONTROL ROD DRIVE SCREU. THE POUER BEHAVIOUR INDICATES THAT THE TORQUE INCREASE IS RUNNING- TIME-DEPENDENT, E G HEAT OF FRICTION CAUSED BY CRUD ACCUMU- LATION BETUEEN THE CONTROL ROD DRIVE SCREU AND THE NUT. IN CONNECTION UITH TRIAL OPERATION AFTER MOTOR/GEARBOX REPLACE- MENT, ANY STICKING BEHAVIOUR OR CRUD ACCUMULATION HAS BEEN ELIMINATED BY THE INTERACTION BETUEEN THE COOLED-OFF CONTROL ROD DRIVE CCRUD REMOVAL FLOU MAX. ABOUT 70 O C) AND MOVEMENT- INDUCED UATER FLOU. VERIFICATION OF RIGHT CRUD REMOVAL FLOU FOR INDIVIDUAL CONTROL ROD DRIVE IS NOT POSSIBLE. REPLACED COMPONENTS THE CONTROL ROD DRIVE MOTOR HAS BEEN CHECKED IN THE NO-LOAD CONDITION AND FOUND TO FUNCTION SATISFACTORILY CINSULATION- UIND1NG RESISTANCE). THE TORQUE CLUTCH HAS BEEN CHECKED AND FOUND TO FUNCTION SATISFACTORILY. UPON INSPECTION OF THE GEARBOX, A THROUGH CRACK UAS FOUND IN THE INTERNAL MOUNTING PLATE THAT DIVIDED THE PLATE INTO TUO PARTS, UHICH HOUEVER UERE FIXED BY EXISTING BOLTS AND LOCATING PINS. NO DAMAGES HAVE BEEN OBSERVED ON GEAR SURFACES, BEARINGS OR SHAFTS. SINCE INTERNAL DEFECTS IN THE GEARBOX CANNOT AFFECT THE TORQUE LIMITER, THIS DEFECT CANNOT EXPLAIN THE TORQUE TRIP. TRACES OF PAINT IN THE CRACK INDICATE INITIATION PRIOR TO COMMISSIONING. A NUMBER OF OTHER CRACKS IN THE MOUNTING PLATE INDICATE IMPROPER LOADING, POSSIBLY CONSEQUENTIAL FAULTS OF THE PRIMARY CRACK. A DECISION UAS MADE THAT THE CONTROL ROD DRIVE SHOULD BE RESTORED TO
THE OPERABLE STATE UITH FULL MOBILITY. THE REAC- TOR UAS THEREFORE BROUGHT TO COLD SHUTDOUN TO PERMIT RE- PLACEMENT OF THE CONTROL ROD DRIVE. THE CONTROL ROD DRIVE MOTOR, INCLUDING GEARBOX, UAS RE- PLACED. THE CONTROL ROD DRIVE UAS HAND-CRANKED AND THEN TEST-RUN THROUGH ITS ENTIRE TRAVEL THREE TIMES AND EXHIBITED LOU POUER
- 14 -
CONSUHPTION. THE CONTROL ROD DRIVE UAS THEREFORE DECLARED OPERABLE ON 850227 AT 1600 HOURS.THE CONTROL ROD DRIVE, UHICH UAS INSTALLED DURING THE 1982 REFUELLING OUTAGE, UILL BE TAKEN OUT DURING THE 1985 REFUELLING OUTAGE FOR FOLLOU-UP INSPECTION. A MATERIAL ANALYSIS OF THE GEAR'S MOUNTING PLATE SHOWS NORMAL I1ATERIAL PROPERTIES. GEAR MOUNTING PLATES UILL BE INSPECTED ON A RANDOM SAMPLE BASIS.
Fl-RO-810/85 - SYSTEM 762 UATER FOR FIRE PROTECTION
PERIODIC TEST, MOBILITY TEST 762 V606 (SPC25 ACCORDING TO OPERATING INSTRUCTION 1 762-12
TYPE: 106 203 304 409 502 605 704 812 905
IN CONNECTION UITH PERIODIC TEST, MOBILITY TEST 762 V606 CSPC2) IN ACCORDANCE UITH OPERATING INSTRUCTION 1 762-12, THE VALVE REMAINED IN A CLOSED P05ITI0N DESPITE OPENING COntlAND. UITH THE AID OF ADDITIONAL FORCE IN THE FORK OF A URENCH PLUS REGULAR POUER FEED, THE VALVE UAS EXERCISED. AFTER THIS, THE VALVE OPENED IN RESPONSE TO OPENING COMMAND, BUT THE OPENING TIME UAS > THE SPECIFIED 30 SECONDS. THE VALVE CLOSED SATISFACTORILY. THIS INDICATES THAT THE VALVE UAS NOT MECHANICALLY STUCK. 762 V653, THE REGULATING VALVE IN THE AIR FEED TO THE CONTROLLER'S OPEN PLUNGER, UAS THERE- AFTER OPENED ONE TURN. THIS RESULTED IN THE VALVE OPENING IN ONLY 5 SECONDS. V653 UAS THROTTLED SO THAT THE VALVE'S RUNNING TIME UAS ABOUT 25 SECONDS. AUTOMATIC SPRINKLING OF THE SPACE IN QUESTION UOULD NOT OCCUR IN THE EVENT OF FIRE. HOUEVER, SPRINKLING HAS BEEN POSSIBLE BY MANUALLY OPENING 762 V608 IN THE BYPASS LINE OVER THE SPRINKLER VALVE. OUTAGE LIMIT 7 DAYS ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.15D. INSUFFICIENT CONTROL AIR PRESSURE, PARTIALLY CLOGGED CON- STRICTION. RAISED CONTROL AIR PRESSURE TO THE CONTROLLER'S OPEN PLUNGER. CHECK OF AIR FEED TO THE CONTROLLER UITH RESPECT TO CLOG- GING OF CONSTRICTIONS IN FILTER AT SUITABLE OPPORTUNITY.
Fl-RO-011/85 - SYSTEM 172 COOLING UATER OUTLET
LEVEL MONITORING IN SURGE SHAFT OUT OF ORDER
TYPE: 106 201 302 409 503 611 702 812 901
ON 1985-04-07 AT 1600 HOURS, IT UAS DISCOVERED THAT 172 K401 UAS SHOUING AN UNREASONABLY STABLE VALUE ON THE RECORDER INSTRUMENT IN THE CONTROL ROOM. JUDGING FROM THE RECORDER CHART, THE LEVEL MONITOR HAS SHOUN UNREASONABLY STABLE VALUES SINCE 1985-04-05, 2000 HOURS. ACCORDING TO THE TECHNICAL SPECIFICATIONS CHAP. 3.8 E5, DESCENT TO COLD SHUTDOUN REACTOR SHALL TAKE PLACE UNLESS INOPERABLE EQUIPMENT HAS BEEN REPLACED UITH EQUIVALENT MAKESHIFT ARRANGEMENTS OR UITH CONTINUOUS MANUAL SURVEILLANCE. STICKING. THE LEVEL SENSOR UAS EXERCISED AND REPLACED UITH SPECIAL SURVEILLANCE. A PLANT MODIFICATION UAS MADE UHERE THE SENSOR UNIT UAS REPLACED UITH AN ULTRASONIC TYPE OF IDENTICAL DESIGN THAT HAD PREVIOUSLY REEN INTRODUCED FOR 170 K405. 172 K401 MODIFIED AND OPERABLE ONCE AGAIN ON 1985-04-10 AT 1145 HOURS. (TOTAL DOUNTIME 44
15 -
HOURS).
Fl-RO-012/85 - SYSTEM 665 INDICATION AND ALARM SYSTEM SUPPLY
BUSBAR +-24U ONLY BATTERY-FED DURING CIRCUIT BOARD REPLACEMENT IN RECTIFIER LR 115:1
TYPE: 106 201 301 409 504 610 704 812 904
ALARn UAS OBTAINED FOR LOU VOLTAGE LHC 115, UHEREBY .HE VOLTAGE UAS FOUND TO BE JUST BELOU THE ALARM LIMIT. IN CONNECTION UITH CIRCUIT BOARD REPLACEMENT, THE BUSBAR UAS FED ONLY FROM THE BATTERY. IN ACCORDANCE UITH TECHNICAL SPECIFICATIONS CHAP. 3.10 A6, A BUSBAR BECOMES INOPERABLE AFTER 1 HOUR UHEN ONLY BATTERY- FED. CIRCUIT B-.QRD FOR VOLTAGE CONTROL YYR105 DEFECTIVE, SINCE CIRCUIT BOARD REPLACEMENT GAVE CORRECT FUNCTION. A DETAILED ANALYSIS UILL BE PERFORMED ON THE CIRCUIT BOARD TO LOCATE THE PRIMARY FAULT. ATTEMPTS TO TRIM THE CIRCUIT BOARD FOR VOLTAGE CONTROL UERE UNSUCCESSFUL. BECAUSE OF THE RISK OF FURTHER DEGRADED FUNCTION, THE RECTIFIER UAS TAKEN OUT OF SERVICE FOR CIRCUIT BOARD REPLACEMENT. RECTIFIER INOPERABLE ON 850422 BETUEEN 1255 AND 1304 HOURS (DOUNTIME
9 MINUTES). CONTINUED ANALYSIS OF THE CIRCUIT BOARD AND FOLLOU-UP OF THE FUNCTION OF THE RECTIFIER PERFORMED DURING 1985 REFUELLING OUTAGE. IT UAS THEREBY FOUND THAT THE PHASES HAD BEEN SUITCHED ON A CONTACTOR. FOLLOUING CORRECTIVE ACTION, THE RECTIFIER FUNCTIONED SATISFACTORILY.
Fl-RO-013/85 - SYSTEM 314 PRESSURE RELIEF SYSTEM
314 V21 TRIPS ON SUITCHGEAR FAULT
TYPE: 106 201 301 409 503 607 701 812 909
ALARM FOR SUITCHGEAR FAULT UAS OBTAINED UITH THE VALVE IN THE AUTO MODE. SUPPLY UNIT UAS FOUND TO BE TRIPPED AND COULD BE RESTORED. FURTHER TRIP AND FUSE FAILURE UAS OBTAINED IN BOTH THE AUTO AND MANUAL MODES. ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.8A, THE REACTOR MAY BE KEPT IN ITS OPERATING MODE FOR NO MORE THAN SEVEN DAYS IF ONLY ONE PRESSURE RELIEF VALVE IS OPERABLE. DEGRADED ELECTRICAL FUNCTION. BAD CONNECTION TO THE BRAKE COIL MAY HAVE LED TO THE BRAKE NOT RELEASING PROPERLY. CALIBRATION CHECK OF START FREBUENCY LIMITATION CARRIED OUT UITH SATISFACTORY RESULTS. (EXPERIENCE FROM Fl-RO-008/85). CIRCUIT BOARD THYRISTOR CONTROL CLDB 10) REPLACED ON 850513. NO MALFUNCTION HAS OCCURRED SINCE THEN. IN CONNECTION UITH OPERATING TEST ON 850513, THE VALVE FUNCTIONED SATISFACTORILY AND UAS THEREFORE DECLARED OPERABLE ON 850514 AT 1500 HOURS. (TOTAL DOUNTIME 50 H). DURING THE 1985 REFUELLING OUTAGE, THE CONDITION OF THE RELIEF VALVE'S ELECTRIC MOTOR HAS BEEN FOLLOUED UP. THE MOTOR UITH BRAKE HAS BEEN REPLACED. BROKEN ELECTRONIC COMPONENTS HAVE BEEN SENT TO THE SUPPLIERS FOR REPAIR.
- 16 -
TYPE: 106 201 301 409 503 608 701 612 901
ALARM FOR SUITCHGEAR FAULT UAS OBTAINED UITH THE VALUE IN THE AUTO rtODE. ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.8A, THE REACTOR MAY BE KEPT IN ITS OPERATING 11ODE FOR NO MORE THAN 7 SEVEN DAYS IF ONLY ONE PRESSURE RELIEF VALVE IS OPERABLE.
AN OPTICAL COUPLER, SERIES RESISTOR AND TRANSISTOR CT3) UERE FOUND TO BE DEFECTIVE IN THE CIRCUIT BOARD FOR 24V SUPPLY CNER20). CIRCUIT BOARD POUER SUPPLY (NER 20) REPLACED, AND VALVE FUNCTION-TESTED UITH SATISFACTORY RESULTS ON 85-05-27 AT 2150 HOURS. RESISTOR R10 IN CIRCUIT BOARD NER 10 UILL BE CHECKED DURING THE 1965 REFUELLING OUTAGE FOR THE RIGHT POUER VALUE (ABOUT 1 U) FOR 314 V21 , V22.
F1-RO-015/8S - SYSTET1 323 SAFETY INJECTION SYSTEM
323 P4 FAILS TO START DURING RPS TEST
TYPE: 106 203 304 409 502 611 707 812 909
DURING PERIODIC TEST CRPS TEST ACCORDING TO OPERATING INSTRUCTION DI 1 327-7 SUB D), THE RIGHT OBJECT MANOEUVRE UAS NOT OBTAINED C= FAILURE TO START) FOR 323 P4. HOUEVER, THE RIGHT OBJECT MANOEUVRE UAS OBTAINED (= CLOSE FUNCTION) FOR 323 V212. THE RIGHT OBJECT MANOEUVRE UAS OBTAINED UPON REPEATED RPS TEST. LATENT FAULT IN ELECTRONIC EQUIPMENT FOR OBJECT CONTROL OF 323 P4 OR TOO SHORT SIGNAL IN PERFORMANCE OF RPS TEST. UPON REPEATED TESTING, THE EQUIPMENT UAS FOUND TO BE OPERABLE. DURING THE 1965 REFUELLING OUTAGE, MORE THOROUGH FUNCTIONAL TESTING HAS BEEN CARRIED OUT UITHOUT REVEALING ANY FAULT. FAULT URITTEN OFF. REQUIRED
SIGNAL T: IBS UILL BE TAKEN INTOACCOUNT IN CONNECTION UITH TESTING.
Fl-RO-016/85 - SYSTEM 351 BORON INJECTION SYSTEM CBUR)
BORON TANK EMPTIED DURING UORK ON PUMP
TYPE: 102 201 301 409 502 Eii 707 811 909 DURING UORK UITH 351 PI, VALVE VU2 TO THE TANK OPENED DUE TO DISCONNECTION OF LHCU5, UHEREBY THE TANK UAS EMPTIED VIA THE OPEN CONNECTION AT 351 PI. THE BORON TANK UAS FILLED UITH 733 UATER AND THE HEATER STARTED. AFTER HEATING AND DOSAGE, APPROVED CHEMICAL ANALYSIS UAS OBTAINED, 1.45 UT.*, ON 85-06-06, 0900 HOURS. A DISPENSATION UAS REQUESTED AND OBTAINED TO REMAIN IN REFUEL REACTOR MODE FOR 72 HOURS CALL CONTROL ROD DRIVES EXCEPT ONE DEFUSED). DISPENSATION TIME UTILIZED: 48 HOURS.
17 -
SAFETY RELATED OCCURRENCS 850 10 1 TO 850630.
DURING SHUTDOUH UORK ON THE PUMP, NO ACCOUNT UAS TAKEN OF THE FACT THAT VI12 OPENS UHEN THE POUER IS CUT OFF AND THAT A FILLED BORON
TANK IS REQUIRED IN THE REFUEL REACTOR MODE. DOCUMENTATION FOR UORK IN SYSTEM 351 SHALL BE SUPPLEMENTED UITH BLINDING OF PIPE UPSTREAM OF PU11P PRIOR TO UORK IN THE SYSTEM, OR LOCKING OF VALUE VI12 IN THE CLOSED POSITION.
pl-RO-017/85 - SYSTEM 351 BORON INJECTION SYSTEM CBUR5
LOU BORON CONCENTRATION
TYPE: 102 208 309 409 502 605 707 612 909
IN CONNECTION UITH RESTORATION OF 351 CIRCUIT 1, RINSING UAS CARRIED OUT IN ACCORDANCE UITH THE START-UP INSTRUCTIONS. LOCALLY, IT UAS OBSERVED THAT 351 Tl HAD BEEN FILLED TO THE TOP. ANALYSIS OF BORON CONTENT SHOWED 1.22*. OUTAGE LIMIT 48 HOURS ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.3E. RESTORATION OF 351 SYSTEM INCLUDING RINSING TOOK A LONG TIME DUE TO DISCOVERED FAULTS. IN THE MEANTIME, UORK IN CONNECTING SYSTEMS HAD PROBABLY CAUSED VALVE 351 VI12 TO OPEN, UHICH UAS NOT OBSERVED UPON START OF RINSING OF THE SYSTEM. BORON UAS ADDED AND THE EQUIPMENT UAS ONCE AGAIN OPERABLE ON 850611 AT 0900 HOURS C 12 H). RESTORATION INSTRUCTIONS TO BE SUPPLEMENTED UITH REMARK THAT 351 VI12 SHALL BE CLOSED UHEN 733 CONNECTION IS OPENED.
F1-RO-01B/85 - SYSTEM 221 FULL LENGTH CONTROL ROD DRIVES
IN CONNECTION UITH TORQUE CHECK OF CONTROL ROD DRIVE IN ACCORDANCE UITH OPERATING ORDER 105/85, A CONTROL ROD DRIVE OTHER THAN THE SELECTED ONE CAS UITHDRAUN
TYPE: 102 203 302 409 506 610 707 812 904
UHEN SELECTED CONTROL ROD M80 UAS TO BE UITHDRAUN, CONTROL ROD L80 UENT OUT INSTEAD. CONTROL ROD L80 UENT OUT TO 2% BEFORE THE OPERATOR DISCOVERED THAT IT UAS NOT THE EXPECTED ROD THAT UAS MOVING. CONNECTION OF CABLE TO URONG OBJECT DUE TO CONFUSION CAUSED BY INCOMPLETE AND ERODED CABLE MARKING. CHECK AND REMARKING OF CABLES.
Fl-RO-019/85 - SYSTEM 336 SAMPLING SYSTEM
TRIP LEVEL FOR A PARTIAL CONDITION IN M3 CONDITION BEYOND MEASURING RANGE
TYPE: 101 201 304 409 502 611 704 812 909
AT CONDUCTIVITY > 5 /US ACCORDING TO RECORDER CHART, THE LIMIT SUITCH DID NOT TRIP. IN CONNECTION UITH SPECIAL CALIBRATION CHECK DURING THE
IB
1985 REFUELLING OUTAGE, IT UAS FOUND THAT THE TRIP LEVEL FOR THE LiniT SUITCH FOR 12-336 K657 CCHANNEL D IN M3 CONDITION) UAS BEYOND THE TRANSDUCER'S flEASURING RANGE. THE 113 CONDITION UAS CONNECTED IN 2-0F-3 CONFIGURATION DURING A PART OF THE OPERATING SEASON. ELECTRONIC FAULT IN LIMIT SUITCH IN COI1BINATION UITH UNFAVOURABLE MEASURING RANGE. DUE TO THE HIGH SENSITIVITY OF THE CONDUCTIVITY SENSOR, TOGETHER UITH THE TRANSDUCER'S LOGARITHMIC MEASURING RANGE, THE TRIP LiniT 5 /US/CM LIES AT ABOUT 16.6 «A. THE MARGIN TO FULL MEA5URING RANGE C20 HA) IS ONLY ABOUT 1.2 MA OR 6H, WHICH MUST INCLUDE A MARGIN FC CALIBRATION INACCURACY AND ELECTRONIC DRIFT BETUEEN CALIBRATION OCCASIONS. IN ORDER TO OBTAIN 20 flA FROM THE TRANSDUCER, A CONDUCTIVITY APPROACHING INFINITY IS REQUIRED. LIMIT SUITCHES CALIBRATED TO 5 /US/CM. THE CONDUCTIVITY SENSOR'S PROBE OF TYPE "A" UILL BE REPLACED AT THE FIRST OPPORTUNITY UITH TYPE "B", SHIFTING THE MEASURING RANGE BY A FACTOR OF 10 SO THAT THE TRIP VALUE UILL BE LESS SENSITIVE TO ELECTRONS DRIFT. AFTER REPLACEMENT, A DEVIATION OF 1 HA AT NOMINAL 5 /US/CM UILL CORRESPOND TO A CONDUCTIVITY INCREASE OF ABOUT 1 /US/CM, AT NOMINAL 10 /US/CM A CONDUCTIVITY INCREASE OF ABOUT 2 /US/CM.
Fl-RO-020/85 - SYSTEM 221 FULL LENGTH CONTROL ROD DRIVES
STICKING CHECK VALVE
TYPE: 102 207 303 409 504 611 702 812 901
IN CONNECTION UITH CHECK OF STICKING CONTROL ROD DRIVE 221 K35 IN ACCORDANCE UITH Fl-RO-009/85, IT UAS DISCOVERED THAT THE CONTROL ROD DRIVE'S CHECK VALVE IN THE SCRAM INLET UAS STUCK IN THE CLOSED POSITION. A PROBABLE CONSEQUENCE IS INTERRUPTION OF CRUD REMOVAL FLOU, UITH
RISK OF INCREASED FRICTION IN THE SCREU MECHANISM. THE OBSERVATIONS HADE IN F1-RO-0P9/85 POINT TOUARDS INTERRUPTION OF CRUD REMOVAL FLOU FOR A CERTAIN PERIOD PRIOR TO 850227. (PREVIOUS REACTOR TRIP IS DATED 3408063. AN IMPROBABLE CONSEQUENCE IS THAT THE SCRAfl FLOU UILL BE BLOCKED BASED ON - ASEA-ATOM'S INVESTIGATION, UHICH INDICATES THAT THERE IS NO REPORTED CASE UHERE REACTOR TRIP HAS FAILED TO OCCUR DUE TO A FAULT IN THE VALVE. - A PARTIAL SCRAM UAS PERFORMED ON 850225 INCLUDING 221 K35, UHICH FUNCTIONED SATISFACTORILY. OF THE TOTAL 29 CHECK VALVES CHECKED DURING THE 1985 REFUELLING OUTAGE, POSITION P40 UAS ALSO NOTED FOR SLIGHT STICKING, BUT THERE THE DISK UAS IN THE OPEN POSITION. FOR POSITION H25, THE DISK UAS EASILY MOVEABLE UITH THE SPRING COMPRESSED. THE SYSTEM FUNCTION IN 354-221 IS SUCH THAT UPON CONCLUSION OF SCRAM INSERTION, A BRIEF BACKFLOU IS OBTAINED UHICH CLOSES THE DISK AND COMPRESSES THE SPRING IN THE CHECK VALVE. IF THERE IS A TENDENCY TOUARDS STICKING OF THE DISK, THE DISK CAN, DUE TO THE LOU DIFFERENTIAL PRESSURE OF THE CRUD REMOVAL FLOU, REMAIN IN THE CLOSED POSITION UNTIL THE NEXT SCRAM FORCES THE DISK UP DUE TO A LARGE PRESSURE DIFFERENCE, AFTER UHICH THE ABOVE-DESCRIBED CYCLE CAN BE REPEATED. FOR THE CHECK VALVE IN 221 K35, IT UAS FOUND THAT THE END OF THE SPRING UIRE UAS BENT UNDER ITSELF, UHEREBY THE CLEARANCE BETUEEN THE DISK'S FOUR GUIDE FINGERS AND THE VALVE BODY UAS INSUFFICIENT. IT HAS NOT BEEN POSSIBLE TO CLARIFY WHETHER THE SPRING
- 19 -
UIRE ASSUHED THIS POSITION DURING MANUFACTURE/FITTING OR DURING A LATER SCRAN MANOEUVRE, POSSIBLY IN COMBINATION UITH OXIDE DEPOSITS. REVIEW OF THE DESIGN OF THE DISK/SPRING. IN CONNECTION UITH CONTROL ROD DRIVE TEST PRIOR TO STARTUP AFTER THE 1985 REFUELLING OUTAGE, THE NOTOR CURRENTS OF ALL CONTROL ROD DRIVES UILL BE EVALUATED AT FULL TRAVEL IN ORDER TO VERIFY LOU FRICTION AND THEREBY THAT NO FUNCTION- OBSTRUCTING CRUD BUILD-UP HAS TAKEN PLACE DURING THE PRECEDING OPERATING SEASON. THE HYDRAULIC SCEAM FUNCT.'ON OF ALL CONTROL ROD DRIVES UILL BE VERIFIED IN CONNECTION' UITH STARTUP AFTER THE 1985 REFUELLING OUTAGE BY INSERTION, BOTH UITH COLD PRESSURELESS REACTOR AND UITK HOT PRESSURIZED REACTOR.
F2-RO-001/85 - SYSTEM 354 HYDRAULIC S/STEM FOR CONTROL ROD DRIVES CBUR)
MALFUNCTIONING LEVEL SENSOR IN SCRAM TANK
DATE .-850109 / EL. POUER 937 HUE / CATEGORY: 3
TYPE: 106 201 301 409 502 603 70(3 312 909
OW 1985-01-09 AT 1255 HOURS, L3 UAS OBTAINED IN 354 T3 UITHOUT PRECEDING LI OR L2 SIGNAL. AFTER ELECTRICAL FAULT TRACING, THE MALFUNCTION IN THE LEVEL SENSOR DISAPPEARED. THE SENSOR UAS DISMANTLED FOR FAULT TRACING. SEE BELOU. INSPECTION OF THE SIGNAL PATHUAYS TO THE CONTRC'- ROOM AND OF THE CONTACT CARTRIDGE IN THE LEVEL SENSOR UAS CARRIED OUT. UHILE FAULT TRACING UAS IN PROGRESS, THE FAULT DISAPPEARED. NO f-AULT COULD BE
FOUND EITHER IN THE CONTACT CARTRIDGE OR THE UIRING. INSULATION CHECK OF FLOAT, MAGNETS AND SHAFT JOURNAL UERE CARRIED OUT AFTER THE SENSOR HAD BEEN DIS- MANTLED. NO DAMAGES OR OTHER FAULTS COULD BE FOUND. FUNCTIONAL TESTING CARRIED OUT UITH SATISFACTORY RESULTS. 354 GROUP 3 ONCE AGAIN OPERABLE ON 85-01-10 AT 1700 HOURS.
F2-RO-002/85 - SYSTEM 321 RESIDUAL HEAT REMOVAL SYSTEM
321 PI TAKEN OUT OF SERVICE DUE TO POOR INSULATION RESISTANCE
TYPE: 106 207 312 409 503 607 702 812 909
IN CONNECTION UITH INSPECTION OF 321 PI, THE INSU- LATION LEVEL BETUEEN EARTH AND PHASE UAS FOUND TO BE 0.9 M L . IN CONNECTION UITH AN EARLIER INSPECTION DURING UEEK 36 OF 1984, THE INSULATION RESISTANCE UAS MEASURED AT ABOUT 4 M L . SINCE THE CONDITION OF THE PUMP UITH RESPECT TO INSULATION RESISTANCE HAD DETERIORATED CONSIDERABLY OVER A SHORT PERIOD OF TIME, IT UAS DECIDED TO SHUT DOUN AND REPLACE 321 PI DESPITE THE FACT THAT THE PUMP IS FORMALLY REGARDED AS OPERABLE CEARTH FAULT ALARM IS OBTAINED AT ABOUT 0.5 M L ). SHUTDOUN UAS BEGUN ON 1985-01-16 AT 1800 HOURS. INSULATION DAMAGES IN STATOR UINDING AND CABLE ENTRIES. THE PUMP MOTOR UAS REPLACED UITH A RESERVE UNIT. 321 PI ONCE AGAIN OPERABLE ON 1985-01-18 AT 0000 HOURS. FAULT TRACING ON THE MOTOR REVEALED THAT TUO CABLE ENTRIES HAD INSULATION DAMAGES AND UATER LEAKAGE. THE STATOR UIND- ING ALSO HAD INSULATION DAMAGES AND THE LEADS EXHIBITED THE FIRST SIGNS OF ABRASION DAMAGES. TUO INSULATING
- 20 -
PLATES AT THE CONNECTION BUSSES UERE HEAT- DAMAGED DUE TO OVERHEATING. THE GROOVE INSULATION UAS SEVERELY DEFECTIVE AT CERTAIN PLACES UHERE THE STATOR UIND- ING (JAS IN DIRECT CONTACT UITH THE STATOJ? LAMINATIONS. A LONG-RANGE PROGRAMME HAS BEEN DESCRIBED FOR THE ABOVE PU11PS.
321 U5 TRIPPED ON TORQUE IN CLOSE DIRECTION IN CONNECTION UITH RPS TEST.
TYPE: 106 203 303 409 584 605 704 812 909
IN CONNECTION UITH RPS CREACTOR PROTECTION SYSTEM) TESTING AFTER CONCLUDED IN-SERVICE PREVENTIVE MAINTENANCE, 321 V5 TRIPPED ON TORQUE
IN THE CLOSE DIRECTION. REPAIR CRITERION ACCORDING TO TECHNICAL SPECIFICATIONS 3.8B IS 7 DAYS, OF UHICH 6 DAYS UERE UTILIZED FOR IN-SERVICE PREVENTIVE MAINTENANCE IN ACCORDANCE UITH A SPECIAL DISPENSATION. THE VALVE UAS CLOSED MANUALLY. INCORRECTLY ADJUSTED CLOSE TORflUE. IN-SERVICE RPS TESTING HAD PREVIOUSLY SHOUN SATISFACTORY VALVE FUNCTION. COOLING DUE TO SHUT-OFF FOR PREVENTIVE MAINTENANCE PROBABLY CAUSED THE VALVE TO OPERATE MORE SLUGGISHLY. UPUARD ADJUSTMENT OF TRIP TORQUE FROM 40 KGFM TO CORRECT VALUE OF 65 KGFM. THE VALVE UAS TESTED AFTER CORRECTIVE ACTION UI7H SATISFACTORY RESULTS.
F2-RO-004/85 - SYSTEM 655 STANDBY BATTERY SYSTEM, INVERTERS AND
BATTERIES
TYPE: 106 201 301 409 502 609 701 603 902 ON 1985-03-18 AT 0650 HOURS, ALARM 655 K921 "OVERFREQUENCY" UAS OBTAINED. FREQUENCY FLUCTUATION BETUEEN 50 AND 52 HZ CAUSED 0R21 (DC/AC CON 'FJRTER) TO TRIP AT 0700 HOURS. AUTOMATIC CHANGEOVER TO BUSBAR A^IB FUNCTIONED FAULTLESSLY UITH POUER INTERRUPTION LASTING NORMAL l.:j SECONDS. OUTAGE LIMIT ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.10 A5: 48 HOURS. DUE TO AGING PHENOMENON, THE CONTACTOR IN THE SPEED GOVERNING CIRCUIT CFIELD MONITORING CIRCUIT) STUCK. THE FAULT UAS TRACED TO A CONTACTOR OF TYPE EG20L C110 V) IN THE SPEED GOVERNING CIRCUIT CFIELD MONITORING CIRCUIT). THECONTACTOR UAS REPLACED AND A NEU TRIAL START UAS PERFORMED UITH SATISFACTORY RESULTS. 0R21 (DC/AC ROTATING CONVERTER) ONCE AGAIN OPERABLE ON 1985-03-18 AT 1300 HOURS. ALL CONTACTORS OF THE ABOVE TYPE UERE CHECKED AND REPLACED UHERE NECESSARY DURING THE 1983 REFUELLING OUTAGE (F2-RO-007/83). INVESTIGATIONS ARE UNDERUAY REGARDING THE POSSIBILITY OF REPLACING THE ABOVE CONTACTOR OF TYPE EG20L UITH ASEA'S NEU CONTACTOR UITH TYPE DESIGNATION EH.
- 21
F2-RO-005/85 - SYSTEM 221 FULL LENGTH CONTROL ROD DRIVES
PISTON TUBE FOR CONTROL ROD 040 SEPARATED FROI1 DRIUE NUT UPON UITHDRAUAL IN CONNECTION UITH START-UP AFTER REACTOR TRIP.
TYPE: 104 201 303 409 504 611 707 812 902
UPON START-UP AFTER REACTOR TRIP ON 1985-03-18, THE COMPUTER ALARI1 "ROD NUT SEPARATION CONTROL ROD 040" UAS OBTAINED AT %\. A SCRAM TEST UAS PERFORMED ON THE GROUP BELONGING TO CONTROL ROD 040. RENEUED ATTEMPTS TO UITHDRAU THE CONTROL ROD FAILED. THE PISTON TUBE SEPARATED FRO11 THE DRIVE NuT UITHOUT THE CONTROL ROD LEAVING THE INSERTED POSITION. THE SEPARATION UAS PROBABLY CAUSED BY A DETACHED BOX BOLT HEAD FALLING INTO THE GAP BETWEEN THE SEAL SEAT AND THE PISTON TUBE. OWING TO THE EXISTING CHAMFERS IN THE DESIGN, OBJECTS CAN EASILY BECOME UEDGED FAST AND PREVENT UITHDRAUAL. NO BOX BOLT HEAD UAS FOUND IN GUIDE TUBE 040 DURING THE 1984 REFUELLING OUTAGE. NEU CONTROL ROD SEQUENCE UAS DEVELOPED AND IMPLEMENTED UHERE CONTROL ROD 040 UAS LEFT IN THE INSERTED POSITION. THE MANIPULATING MOTOR FOR COKTROL ROD 040 UAS DEFUSED AND UAS THEREBY REGARDED AS OPERABLE IN ACCORDANCE UITH TECHNICAL SPECIFICATIONS CHAP. 3.3C. CONTROL ROD DRIVE 040 UILL UNDERGO SERVICE DURING THE 1985 REFUELLING OUTAGE AND THE ASSOCIATED SUPERCELL UILL BE INSPECTED.
F2-RO-006/85 - SYSTEM 211 REACTOR VESSEL
INCORRECTLY INDICATING INSTRUMENT, REACTOR VESSEL LEVEL
TYPE: 106 201 301 409 502 611 702 812 909
IN CONNECTION UITH POUER INCREASE ON 1985-03-21, ALARM UAS OBTAINED FROM 211 K403, FINE LEVEL REACTOR VESSEL. THE INDICATION THEN SHOUED 202 MM ABOVE THE NORMAL LEVEL C3.8 METRES ABOVE CORE LEVEL). THE TRANSMITTER HAD BEEN CALIBRATED DURING UEEK 18, 1985, IN CONNECTION UITH THE ONGOING PROJECT '••^-SERVICE PREVENTIVE MAINTENANCE". A SIMILAR INCORRECT INDICATION HAS SINCE BEEN DISCOVERED C1985-04-03) ON THE REACTOR'S COARSE MONITOR 211 K412. THIS TRANSMITTER HAS ALSO BEEN CALIBRATED UITHIN THE IN-SERVICE PREVENTIVE MAINTENANCE PROJECT, DURING UEEK 13. IN CONNECTION UITH IN-SERVICE PREVENTIVE MAINTENANCE ON THE ABOVE TRANSMITTER, A CALIBRATION CHECK UAS ALSO CARRIED OUT, UHEREBY THE TRANSMITTER IS DEPRESSURIZED FROM 70 BAR TO ATMOSPHERIC PRESSURE. AFTER COMPLETED CALIBRATION, UHICH DID NOT INDICATE ANYTHING ABNORMAL, THE TRANSMITTER UAS PRESSURIZED UITH THE BELLOUS VERY QUICKLY AND ONE-SIDELY TO START UITH TO 70 BAR. THIS RAPID PRESSURIZATION, INCLUDING UATER HAMMER IN THE TRANSMITTER, HAS A DETRIMENTAL EFFECT ON THE MEASUREMENT CELL. TRANSMITTERS 211 K403 AND 211 K412 UERE REPLACED AND UERE ONCE AGAIN OPERABLE ON 1985-03-21, 0900 HOURS AND 1985-04-03, RESPECTIVELY. THE ABOVE-DESCRIBED CALIBRATION OF LEVEL TRANSMITTERS UILL NOT BE PERFORMED IN THE FUTURE AS IN-SERVICE PREVENTIVE MAINTENANCE. THIS MEASURE SHOULD BE PERFORMED DURING THE REFUELLING OUTAGE UITH AN UNPRESSURIZED REACTOR VESSEL. SIMILAR SYMPTOMS HAVE PREVIOUSLY BEEN
- 22 -
SAFETY RELATED OCCURRENCS 850101 TO 8S0630.
OBTAINED DURING TESTING OF THE ZERO POINT OF TRANSMITTERS, UHICH THE
TECHNICAL SPECIFICATIONS PRESCRIBES SHOULD BE DONE EVERY 3RD MONTH. IN THIS TEST AS UELL, UHICH MUST BE PERFORMED IN SERVICE, A VERY RAPID AND ONE-SIDED PRESSURIZATION OF THE TRANSMITTER TAKES PLACE. THIS TEST SHOULD THEREFORE NOT BE PERFORMED IN-SERVICE, AND THE PURPOSE OF THE TEST IS ACHIEVED BY THE PERIODICAL TEST "REASONABLENESS CHECK", UHICH IS CARRIED OUT ONCE A UEEK. REVISION OF THE TECHNICAL SPECIFICATIONS HAS BEEN INITIATED.
F2-RO-007/85 - SYSTEM 322 CONTAINMENT SPRAY SYSTEM
DEFECTIVE CONTACTOR 322 V205
TYPE: 106 202 308 409 506 608 701 612
THE CONTACTOR UAS REPORTED DEFECTIVE BY THE CONTROL ROOM OUING TO THE FACT THAT IT UAS BUZZING. AFTER INSPECTION BY THE ELECTRICAL MAINTENANCE CREU, IT UAS DECIDED THAT THE CONTACTOR SHOULD BE REPLACED SO AS NOT TO RISK ITS BECOM- ING INOPERABLE. DURING THE REPLACEMENT UHEN 322 V205 HAD BEEN BLOCKED IN THE CLOSED POSITION, THE SPRINKLER FUNCTION FOR CIRCUIT 2 CB SUB) UAS INOPERABLE FOR 15 MINUTES: 1000-1015 HOURS, 1985-03-27. REPAIR CRITERION ACCORDING TO TECHNICAL SPECIFICATIONS 3.8C:30 DAYS. PARTICLES OF DIRT HAVE ENTERED THE CONTACTOR. THESE PARTICLES HAVE THEN BOUND MOISTURE, UHICH HAS GIVEN RISE TO SOME COR- ROSION ON THE IRON ARMATURE. CONTACTOR REPLACED UITH NEU ONE. NORMAL PREVENTIVE MAINTEN- ANCE IS BEING PERFORMED AS BEFORE.
F2-RO-008/85 - SYSTEM 221 FULL LENGTH CONTROL ROD DRIVES
CONTROL ROD L70 SEPARATED FROM DRIVE NUT UPON UITHDRAUAL
TYPE: 106 201 303 409 502 611 701 812 902
UPON UITHDRAUAL, CONTROL ROD L70 GOT STUCK IN THE 94?£P0SITI0N. THE SAME CONTROL ROD UAS STUCK IN THIS POSITION BEFORE THE REACTOR TRIP ON 1985-03-18, SEE F2-RO-021/84. PRIOR TO POUER ASCENT AFTER THE REACTOR TRIP, L70 UAS TESTED BOTH MECHANICALLY AND HYDRAULICALLY AND UAS FOUND TO BE OPERABLE. REPAIR CRITERION ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.3 B2: 7 DAYS. THE PROBABLE CAUSE OF THE SEPARATION BETUEEN THE PISTON TUBE AND THE DRIVE NUT IS THAT A DETACHED BOX BOLT HEAD HAS BECOME LODGED IN THE
GAP BETUEEN THE SEAL SEAT AND THE PISTON TUBE. DUE TO EXISTING CHAMFERS IN THE DESIGN, OBJECTS CAN EASILY GET UEDGED AND PREVENT UITHDRAUAL. NO BOX BOLT HEAD HAS BEEN FOUND IN CONTROL ROD GUIDE TUBE L70 IN CONNECTION UITH INSPECTION DURING THE 1984 REFUELLING OUTAGE. HOUEVER, A BOX BOLT CAME LOOSE DURING THE 83/84 OPERATING SEASON IN THE SUPERCELL IN QUESTION, AND A TOTAL OF 31 DETACHED BOX BOLT HEADS HAVE NOT BEEN FOUND IN THE REACTOR VESSEL. IT IS, HOUEVER, SOMEUHAT REMARKABLE THAT SEPARATION OCCURRED ONCE AGAIN IN THE 945« POSITION. CONTROL ROD L70 AND ITS SYMMETRY ROD R30 UERE LEFT IN THE 94*
- 23 -
POSITION AND A NEW CONTROL ROD SEQUENCE UAS IMPLEMENTED. THE SHUTDOUN MARGIN UAS CALCULATED IN CONNECTION UITH
F2-RO-009/85 - SYSTEti 751 CO11PRESSED AIR PLANT FOR INSTRUMENT- AND AIR
CONTROL
TYPE: 106 203 303 409 502 605 70? 812 909 IN CONNECTION UITH PERIODIC TESTING OF LOGIC CHANNELS AND PARTIAL CONDITIONS IN SYSTEM 516, NO TEST RESPONSE UAS OBTAINED IN THE A SUB. FAULT TRACING REVEALED THAT ONE OF THE FOUR SOLENOID VALVES CPILOT VALVES) FOR SCRAti VALVE 354 VI16 UAS nALFUNCTIONING SO THAT NO TEST RESPONSE UAS OBTAINED. THE CONSEQUENCE OF THE FAULT IS THAT A PARTIAL CONDITION CTHE 354 FUNCTION GROUP 16) IN THE SS CHAIN'S A CHANNEL IS BLOCKED AND CONDITION FORMATION IS THEREBY 2-0F-3-C0NNECTED. REPAIR CRITERION ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.1: 60 DAYS. MECHANICAL FAULT IN SOLENOID VALVE. OUING TO THE EXISTING SYSTEM DESIGN, THE SOLENOID VALVE CANNOT BE REPLACED UITHOUT THE CONTROL AIR AFFECTING 9 SCRAM VALVES BEING SHUT OFF. THIS UOULD RENDER 9 SCRAM GROUPS TEMPORARILY INOPERABLE. THE SOLENOID VALVE UILL BE REPLACED IN CONNECTION UITH THE FIRST REACTOR OUTAGE. A DISPENSATION HAS BEEN OBTAINED TO CONTINUE OPERATION UNTIL THE 1985 REFUELLING OUTAGE. AFTER THE SOLENOID VALVE IS REMOVED, IT UILL BE EXAMINED TO DETERMINE THE CAUSE OF ITS NON-FUNCTION, IF POSSIBLE.
F2-RO-010/85 - SYSTEM 314 PRESSURE RELIEF SYSTEM
CONTROL VALVE 314 V21 TRIPPED ON SUITCHGEAR FAULT
TYPE: 106 201 301 409 503 605 701 812 901
UITH 314 IN THE EMERGENCY PREPAREDNESS MODE AND DURING POUER OPERATION, 314 V21 TRIPPED ON SUITCHGEAR FAULT. CONTROL VALVE V21 UAS SUITCHED OVER FROM AUTOMATIC TO MANUAL MODE AT THE SAME TIME AS THE VALVE CLOSED. IN ACCORDANCE UITH THE DESIGN REQUIREMENTS, THE OTHER CONTROL VALVE 314 V22 CLOSED DUE TO "FOLLOUING" BUT REMAINED IN THE AUTOMATIC MODE. IF CONSTANT PRESSURE CONTROL HAD BEEN CALLED FOR IN THIS nODE, SHUTOFF VALVE V20 UOULD IHMEDIATELY HAVE OPENED AT THE SAME TIME AS CONTROL VALVE V22 UOULD HAVE BEGUN PRESSURE CONTROL FROM THE CLOSED POSITION INSTEAD OF THE OPEN POSITION, UHICH IS NORMAL. ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.8A, THE REACTOR MAY NOT BE KEPT IN ITS OPERATING HODE FOR MORE THAN 8 DAYS IF ONLY ONE PRESSURE CONTROL VALVE IS OPERABLE. BURNT RESISTOR R10 IN NER20 VOLTAGE UNIT. THE VOLTAGE UNIT UAS REPLACED AND THE BURNT RESISTOR, UHICH UAS UNDERSIZED, UAS REPLACED UITH A 1 OHM RESISTOR. THE VALVE UAS FUNCTION-TESTED UITH SATISFACTORY RESULTS ON 1985-04-23 AT 0900 HOURS. TOTAL DOUNTIME 4 HOURS. A PROPOSAL FOR A DESIGN CHANGE HAS BEEN PREPARED UHERE THE HON-DEFECTIVE CONTRCL VALVE IS PREVENTED FROM CLOSING DUE TO "FOLLOUING".
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F2-K0-Ö11/85 - SYSTEM 655 STANDBY BATTERY SYSTEM, INVERTERS AND BATTERIES
AFTER UIDE FREQUENCY 5UINGS AND ALARM FOR OVER- FREQUENCY, 0R22 UAS STOPPED FOR INSPECTION.
TYPE: 106 201 301 409 503 608 701 812 909
ON 1985-04-23 AT 1253 HOURS, ALARM 655 K922, OVERFREQUENCY, UAS OBTAINED FRO11 0R22 CDC/AC ROTATING CONVERTER). THE FREQUENCY UAS FLUCTUATING UIDELY. AN ATTEMPT TO AUTO- SYNCHRONIZE AT 220-S2 FAILED, UHEREBY MANUAL SYNCHRONIZATION'S CARRIED OUT. 0R22 UAS STOPPED FOR FAULT TRACING. DURING THE TIME 0R22 UAS OUT OF SERVICE, THE FEED TO THE BATTERY- BACKED GRID UAS GUARANTEED BY THE FACT THAT DG220 UAS SYNCHRONIZED IN ACCORDANCE UITH TECHNICAL SPECIFICATIONS CHAP. 3.10.A5. OUTAGE LIMIT 48 HOURS IN ACCORDANCE UITH TECHNICAL SPECIFICATIONS CHAP. 3.10.A5. PROBABLY BAD CONNECTION IN SPEED GOVERNING CIRCUIT. IN CONNECTION UITH FAULT TRACING, THE CONTACTORS, THE MOTORIZED POTENTIOMETER ON CIRCUIT BOARD QAPH 211 AND THE CONNECTIONS ON THE THYRISTORS UERE CHECKED UITHOUT ANYTHING ABNORMAL BEING FOUND. THE CONVERTER UAS STARTED AND TEST-RUN AT NO-LOAD ON TUO OCCASIONS UITH SATISFACTORY RESULTS. ON 1985-04-23 AT 1710 HOURS, OR22 UAS SYNCHRONIZED AND AT 220-S2 UAS DISCONNECTED, UHEREBY OR22 UAS ONCE AGAIN OPERABLE CDOUNTIME ABOUT 4 HOURS). AN AIR SAMPLE HAS BEEN TAKEN FROM THE CONCERNED AREA FOR ANALYSIS OF ANY AIRBORNE PARTICLES. CONTACTOR EG20L IN THE SPEED GOVERNING CIRCUIT UILL BE REPLACED UITH A NEU TYPE DURING THE 1985 REFUELLING OUTAGE.
321 P2 TRIPPED DUE TO EARTH FAULT
TYPE: 106 201 301 409 503 611 702 809 901
ON 1985-06-08 AT 2357 HOURS 321 P2 TRIPPED. AT THE SAME TIME, ALARM UAS ISSUED FOR 654 K933 (NEUTRAL POINT VOLTAGE, OPERATING INSTRUCTION 239). LOCAL INSPECTION IN THE SUITCHGEAR REVEALED THAT 321 P2 HAD TRIPPED ON OVERCURRENT. THE EMERGENCY ELECTRICAL CREU UAS SUMMONED FOR MEGGER TESTING OF PUMP MOTOR 321 P2. EARTH FAULT <0.1 OHM TO EARTH UAS FOUND. REPAIR CRITERION ACCORDING TO TECHNICAL SPECIFICATIONS CHAP. 3.8B: 7 DAYS DOUBLE EARTH FAULT <0.1 OHM. TUO CABLE ENTRIES HAD EARTH FAULTS, UHICH CAUSED THE SHORT CIRCUIT. SUITCH TO RESERVE MOTOR OF STAINLESS DESIGN. THE REPLACED MOTOR UAS INSULATION-TESTED AFTER MOUNTING AND PRESSURIZATION ON 850610 AT 1300 HOURS AND THEN HAD ONLY 0.25 MEGAOHM TO EARTH. MOTOR PREVIOUSLY TESTED UET IN UORK- SHOP UITH VALUE > 20 000 MEGAOHMS. PROBABLY FAULT IN INSULATION LAYER Cii UINDING DURING MANUFACTURE. AT THIS POINT, IT UAS DECIDED THAT THE MOTOR THAT HAD FAILED ON SATURDAY SHOULD BE REPAIRED UITH THE STANDBY "BLACK STATOR" UITH THE TEFZEL UINDING. THE REPAIR UAS FINISHED, THE MOTOR INSTALLED, PRESSURIZED AND TEST-RUN SATISFACTORILY ON 850613 AT 1018 HOURS. THE INSULATION VALUE UAS 300
- 25 -
riEGAOHIIS. THE PUMP UAS THEN TAKEN INTO SERVICE DURING THE DAY. THE STAIN- LESS STEEL riOTOR UAS REPAIRED UITH A NEU STAINLESS STEEL STATOR. ALL 321 PU11PS WILL EVENTUALLY BE REPLACED UITH A NEU CABLE ENTRY.
F2-RO-013/85 - SYSTER 641 TRANSFORMER (SEC VOLTAGE > 1 KV)
UNAPPROVED OIL QUALITY IN TRANSFORMER T29
TYPE: 106 207 312 409 502 609 707 812 909
ON 1985-06-24, T29 UAS TAKEN OUT OF SERVICE FOR INSTALLATION OF A DISCONNECTING SUITCH. THE UORK UAS CARRIED OUT UITH A DISPENSATION FROM TECHNICAL SPECIFICATIONS CHAP. 3.10A1 DURING FOUR DAYS. UHILE UORK UAS IN PROGRESS ON THE DISCONNECTING SUITCH, AN AUDIT UAS PERFORMED ON THE CIRCUIT BREAKER AND TAP CHANGER AND A TRIP TEST UAS PERFORMED. IN ORDER TO BE ABLE TO PERFORM THE AUDIT ON THE TAP
CHANGER, APPROXIMATELY 900 LITRES OF OIL UERE DRAINED, TO BE REFILLED AFTER COMPLETION OF THE UORK. THE SUBSEQUENT OIL ANALYSIS ON 1985-06-27 REVEALED THAT THE QUALITY OF THE OIL UAS MUCH TO POOR TO PERMIT TRANSFORMER T29 TO BE PUT BACK INTO SERVICE. DIRTY OIL DRUMS. THE OIL UAS CHANGED, AFTER UHICH A NEU OIL ANALYSIS UAS PERFORMED UITH APPROVED RESULTS. TRANSFORMER T29 ENERGIZED AND ONCE AGAIN OPERABLE ON 1985-06-28 AT 2130 HOURS.
F3-RO-001/85 - SYSTEM 520 COMPUTER SYSTEMS
LOSS OF COMPUTER FOR MORE THAN 30 MINUTES
TYPE: 103 201 304 409 502 611 707
2043 HOURS ALL TESSELATORS BECOME DEFECTIVE. 2044 HOURS AUTOMATIC CHANGEOVER FROM B TO A. START-UP OF SYSTEM A AS NEU MAIN SYSTEH FAILED DUE TO "ACUTE MEMORY SHORTAGE". 2120 HOURS MANUAL RESTART OF SYSTEM A. 2149 HOURS SYSTEM IN OPERATION INCL. ALL PCTS CSYSTEM B STARTED UP AT 2215 HOURS AND FILE SYNCHRONIZATION BEGUN). 2222 HOURS AUTOMATIC CHANGEOVER TO OUN SYSTEM A TO A CSYSTEM B INOPERABLE DUE TO THE FACT THAT FILE SYNCHRONIZATION NOT CONCLUDED). MANUAL RESTART OF SYSTEM A FAILED. 2236 HOURS SYSTEM B STARTED UP UITH SYSTEM A'S DISCS. 2304 HOURS SYSTEM IN OPERATION INCL. ALL PCTS. COMPUTER SYSTEM NOT AVAILABLE FOR 1 HOUR AND 6 MINUTES PLUS AN ADDITIONAL 42 MINUTES AFTER THE SECOND FAILURE. TOTAL OUTAGE TIME 1 HOUR AND 48 MINUTEfi. THREE COMPLETELY DIFFERENT FAULTS UERE SUPERIMPOSED ON THIS OCCASION: 1) LOSS OF ALL "TESSELATORS" C IMAGE" GENERATORS). 2) "ACUTE MEMORY SHORTAGE" IN MMI COMPUTER DUE TO RESOURCE SHORTAGE. 3) HARDUARE FAULT IN I1MI COMPUTER. 1) LOSS OF ALL TESSELATORS. ON 850112, SYSTEM A'S CP CARD UAS CHANGED TO A VERSION THAT HAD BEEN MODIFIED SLIGHTLY TO ELIMINATE THIS TYPE OF FAULT. THE FAULT TYPE HAS NOT OCCURRED SINCE THIS CORRECTIVE ACTION. THE FAULT TYPE IS BEING MONITORED. 2) "ACUTE MEMORY SHORTAGE' IN MMI COMPUTER DUE TO RESOURCE SHORTAGE CCF. RO-012/84). ON 850110,
- 26 -
SAFETY RELATED OCCURRENCS 850 101 TO 850630.
A REGISTER BLOCK UAS COUPLED PERrtANENTLY TO THE ROLLER FILE. THE FAULT TYPE IS BEING IIONITORED. 3) HARDWARE FAULT IN MMI CO11PUTER, SYSTEM A. FAULT TRACING IN THE SYSTEM A MMI COMPUTER RESULTED IN REPLACEMENT OF A DEFECTIVE ICP CARD ON 850104 AT 0900 HOURS.
F3-RO-002/85 - SYSTEM 520 COMPUTER SYSTEMS
PCT 12 AND 24 NOT AVAILABLE FOR MORE THAN 30 MINUTES
DATE .-850104 / EL.POUER - / CATEGORY: 3
TYPE: 104 201 304 409 502 611
85-01-94 1622-1748 HOURS CHANGEOVER FROM PCT 24 TO PCT 12 FAILED. NEITHER PCT 4 NOR PCT 12 COULD BE PUT INTO SERVICE. PCT NOT AVAILABLE FOR 1 HOUR AND 18 MINUTES. DUE TO THE FACT THAT AN INDICATION IN THE INDICATION FILE HAD THE URONG STATUS, NO DUMP UAS SENT TO THE PCTS. THE INDICATION UAS PUT IN THE RIGHT STATUS MANUALLY, AFTER UHICH EITHER PCT COULD BE PUT INTO SERVICE AGAIN. ANALYSIS OF THE REASON
UHY INDICATION HAD BEEN PUT IN THE URONG STATUS IS STILL IN PROGRESS.
F3-RO-003/85 - SYSTEM 314 RELIEF SYSTEM
VALVE DID NOT OPEN UPON SS10 CTURBINE TRIP + DUMP PROHIBITION)
DATE.-850116 / EL.POUER 0 MUE / CATEGORY: 3
TYPE: 106 201 304 409 502 605 707 IN CONNECTION UITH REACTOR TRIP 007/85 CAUSED BY TURBINE TRIP + DUMP PROHIBITION, 314VA12 SHOULD HAVE OPENED IN ORDER TO TURN UP 314VA.1. THE CONSEQUENCE UAS VERY MARGINAL UITH REGARD TO PRESSURE RISE IN THE REACTOR VESSEL - ABOUT 0.1 MPA, SINCE THE NEED FOR PRESSURE RELIEF CAPACITY UAS RELATIVELY SMALL. SOME SLUGGISHNESS OR STICKING TENDENCY IN VA12. THE VALVE'S CONTROL SIGNALS UERE CHECKED UITH r^TISFACTORY RESULTS. THE VALVE HAS BEEN OPERATED A NUMBER OF TIMES iUR THE PUR- POSE OF EXERCISING IT AND DETECTING NEU TENDENCIES TOUARDS MALFUNCTION. THE FAULT HAS SO FAR C 1985-02-19) NOT RECURRED, AND TIME RECORDINGS OF THE VALVE'S OPEN FUNCTION SHOU NORMAL VALUES. CHECKING OF VAI2'S FUNCTION AND OTHER EQUIVALENT VALVES IN SYSTEM 314 UILL CONTINUE.
F3-RO-004/85 - SYSTEM 862 FIRE FIGHTING UATER SYSTEM FOR CABLE AREAS
862 VC 52 FAILED TO OPEN UHEN TESTED.
TYPE: 103 203 304 409 503 605
IN CONNECTION UITH TESTTNG OF SPRINKLER VALVES, VC52 FAILED TO FUNCTION. MANUAL SPRINKLING NOT POSSIBLE, SINCE OPEN SIGNAL BLOCKED ALL OPEN MANOEUVRES. DEFECTIVE PRESSURE SUITCH FOR VALVE POSITION INDICATION. PROBABLY UATER-FILLED DURING HIGH-PRESSURE WASHING. INTERRUPT SENSOR FOUND TO BE FAULTLESS. A REVIEU OF THE LOGIC UAS DISCUSSED UITH THE SUPPLIER.
- 27 -
F3-RO-005/85 - SYSTEM 322 CONTAINMENT VESSEL SPRAY SYSTEM
DURING TEST OF THE HD CHAIN'S ACTION ON THE SYSTEM, VALVES VD4, VD23 AND VD50 FAILED TO CLOSE
TYPE: 104 203 304 409 502 610 707 812
DURING FUNCTIONAL TESTING OF 546 HD CONDITIONS, CLOSING OF 322 VD23 FAILED TO OCCUR UHEN THE HD CONDITION UAS TRIPPED. ON CONTINUED TESTING, CLOSURE OF 322 VD4 AND VD50 ALSO FAILED. CABLE CONNECTION IN CUBICLE QDE.lll UAS niSSING. TEMPORARY BRIDGING CARRIED OUT. RETEST CARRIED OUT UITH SATISFACTORY
RESULTS. DOUNTIME 6 HOURS. PERMANENTLY CORRECTED.
F3-RO-006/85 - SYSTEM 323 LOU PRESSURE COOLANT INJECTION SYSTEM
DEFECTIVE CONTROLLER
DATE:850121 / EL.POUER 0 / CATEGORY: 3
TYPE: 104 207 312 409 504 605 701 805 DURING SPECIAL INSPECTION OF 323 VD4, THE SPRING ASSEMBLY FOR TORQUE SETTING UAS FOUND TO BE COMPRESSED AND THE CONTROLLER UAS THEREFORE INOPERABLE. SPRING ASSEMBLY OVERLOADED (DURING TESTING). LONG TIME DELAY, UHICH ON THIS CONTROLLER UITH HIGH SPINDLE SPEED AND UITH SPECIFIED HIGH CLOSE TORQUE HAS RESULTED IN AN EXCESSIVELY LARGE EXTRA TORQUE IN ADDI- TION TO THE SET TORQUE. ONE VALVE CONTROLLER AT A TIME FOR 323VX4 UAS SENT TO HALM\ FOR CORRECTIVE ACTION. THIS MEANS THAT 3 SUBS OF 4 UERE OPERABLE DURING CORRECTIVE ACTION ON EACH VALVE CONTROLLER. THE CORRECTIVE ACTION TIME FOR EACH VALVE CONTROLLER, IN- CLUDING TRANSPORT TIME, UAS ABOUT 2 DAYS. TIME PERIOD: 1985-01-28 - 1985-02-06, INCL. UEEKEND STATION'S OPERATING MODE: HOT STANDBY AND COLD SHUTDOUN, RESPECTIVELY. REPAIR OF CONTROLLER: t. NEU COMPLETE UORM SCREU INSTALLED. 2. NEU COMPLETE TORQUE LIMITER IN- STALLED. 3. NEU HICROSUITCH FOR TORQUE LIMITER INSTALLED. ADJUSTMENT OF CONTROLLER: ZERO POINT ADJUSTMENT OF TORQUE LIMITER ON TEST BENCH. OTHER MEASURES: 1. MEASURES TO REDUCE THE TIME DELAY AND THEREBY THE EXTRA TORQUE. 2. REDUCTION OF CLOSE TORQUE FROM ORIGINAL 690 NM TO 450 NM. 3. CHECK OF EXTRA TORQUE OBTAINED AFTER COMPLETED MEASURES. 4. TIGHTNESS TESTING OF THE VALVES AFTER CHANGE OF CLOSE TORQUE.
F3-RO-008/65 - SYSTEM 521 MAIN COMPUTER
TOTAL LOSS OF COMPUTER > 30 MIN 1207-1248 HOURS
TYPE: 101 201 304 409 501 611 701 812 909
UHEN SYSTEM B UAS TAKEN DOUN FOR PERFORMANCE OF SCHEDULED REVISION 11, SYSTEM A, UHICH UAS THEN THE MAIN SYSTEM.STOPPED. AFTER THIS UAS DISCOVERED, SOME FAULT ANALYSIS UORK UAS CARRIED OUT, AFTER UHICH
- 28 -
SYSTEM A UAS STARTED AS THE 11AIN SYSTEM BY "UARM START". THE STATION UAS IN THE COLD SHUTDOWN HODE AT THE TIME IN QUESTION. TOTAL CONTROL ROD WITHDRAWAL UAS <dX. ANALYSIS OF THE DATA DUMP FROM THIS STOPPAGE AS UELL AS ANALYSIS OF THE DUMP FROM AN AUTOMATIC CHANGEOVER A TO B FROM 1985-02-08 REVEALED A MEMORY FAULT IN MODULE 4 IN SYSTEM A'S MAIN COMPUTER.
DEFECTIVE MEMORY MODULE REPLACED ON 1985-02-08.
F3-RO-009/85 - SYSTEM 622 400 KV SUITCHYARD
TRIPPED DHC BUSBAR
TYPE: 106 201 301 409 503 609 704 812 909 REACTOR TRIP CSS NO. 15) CAUSED BY SS4 LOU LEVEL IN REACTOR VESSEL INITIATED START OF OBJECTS FED FROM SYSTEM 662. 660 V BUSBARS FOR C SUB TRIPPED AT THE SAME TIME SS UAS OBTAINED AS A CONSEQUENCE OF LOAD INCREASES. OVERCURRENT PROTECTION 662 KC 804.1 TRIPPED. THE PROTECTION SUPERVISES THE DHC BUSBAR FOP 660 V C SUB. NO FAULT EXISTED IN SUPPLIED OBJECTS, SO TRIPPING OF THE OVERCUKRENT PROTECTION UAS PROBABLY CAUSED BY THE TOTAL LOAD ON THE BUSBAR UHEN OBJECTS STARTED AT THE SAME TIME IN CONNECTION UITH THE REACTOR TRIP. THE PROTECTION SETTING UAS FOUND TO BE SLIGHTLY OFF BY ABOUT 4.5*. THE SET VALUE IS SUPPOSED TO BE 6 AMPS, EQUIVALENT TO 6000 AMPS OF APPARENT LOAD, BUT UAS INCORRECTLY SET ON 5.75 A, EQUIVALENT TO 5750 AMPS. PROTECTION SET ON 6 AMPS AND ALL OTHER 662 BUSBARS CHECKED. UORK CONCLUDED AT 1600 HOURS ON 1985-02-21. TIME DELAY OF 5 SECONDS INTRODUCED FOR START OF 327PX1 IN ORDER TO AVOID SUPERIMPOSED EFFECT. SAFETY-REVIEUED AND APPROVED.
F3-RO-010/85 - SYSTEM 583 CONTAINMENT VESSEL INSTRUMENTS
REDUCER VALVE DEFECTIVE, LOU FLOU TO GAS ANALYZER 583 KD 741 AND KD 744
TYPE; 105 201 301 409 503 605 703 812 909
ALARM UAS OBTAINED ON LOU FLOU (583 KD341 LI). 583 INOPERABLE IN D SUB. BROKEN DIAPHRAGM IN REDUCER VALVE CAUSED INTERNAL LEAKAGE THROUGH REDUCER VALVE AND LOU FLOU THROUGH MEASURING LOOP. BOTTOM PLUG ON REDUCEK VALVE REMOVED, UHEREBY THE REDUCER VALVE CLOSED AND THE FLOU COULD BE ADJUSTED TO THE OPERATING VALUE. VALVE OPERABLE ON 1965-02-23 AT 1500 HOURS. DOUNTIME ABOUT 12 H. DIAPHRAGM REPLACED AND VALVE RESTORED TO ORIGINAL CONDITION.
29
F3-RO-011/65 - SYSTEM 583 CONTAINMENT VESSEL. INSTRUMENTS
INCORRECT GAS ANALYSIS
TYPE: 106 207 312 409 504 611 704 812 90 1
MOISTURE DISCOVERED IN SUSPENDED BODY METER. SINCE THE GAS ANALYZER IS SENSITIVE TO MOISTURE, IT tlSKS BECOMING INOPERABLE IF THE COOLER/DEHUMIFIER IS NOT REPLACED. FAULT IN FUNCTION OF EC41. METHOD OF DRAINAGE FROM COOLER/DEHUMIDIFIER INCORRECT. UORK ORDER AO 16157200 EC41 REPLACED. DOUNTIME ABOUT 1 HOUR.
REROUTING OF DRAINAGE LINES CARRIED OUT ON BOTH MONITORING ROUTES.
F3-RO-012/85 - SYSTEM 354 HYDRAULIC SCRAM SYSTEM
INOPERABLE LEVEL MONITORING EQUIPMENT IN SCRAM TANK 354TA2
TYPE: 105 201 301 409 503 611 701 612 902
ALARM UAS OBTAINED IN THE CENTRAL CONTROL ROOM, AFTER UHICH THE FAULT UAS TRACED TO 354KA402. IN THE EVENT OF COMMANDED SCRAM, NON-FUNCTION OF 354KA402 UOULD HAVE LED TO NON- CLOSURE OF SCRAM VALVE 354VA2 AND ISOLATING VALVE 352VA22. THE SCRAM FUNCTION UOULD NEVERTHELESS HAVE UORKED. INTERNAL ELECTRONIC FAULT IN THE SENSOR. AO 18465200 354KA402 REPLACED, CALIBRATED AND TESTED. SYSTEM SECTION
ONCE AGAIN OPERABLE AT 1630 HOURS. DOUNTIME 6 HOURS.
TOTAL LOSS OF COMPUTER > 30 MIN 1829-1920 HOURSDATE:850307 / EL.POUER - / CATEGORY:
TYPE: 103 201 304 409 501 611 707 812 909
11 MINUTES AFTER ACTIVATION OF LOAD REJECT UITH ACCOMPANY- ING TSXD (TURBINE TRIP + DUMPING PROHIBITION? AND SS (REACTOR TRIP), SYSTEM A STOPPED, LEADING TO AUTOMATIC CHANGEOVER TO SYSTEM B. SYSTEM B COULD NOT TAKE THE CHANGEOVER, LEADING TO REPEATED SYSTEM RESTARTS. AT 1859, SYSTEM A UAS STARTED UP MANUALLY, AND AT 1920 THE SYSTEM UAS IN OPERATION, INCLUDING ALL PCTS. UHEN THE SYSTEM STOPPED, THE STATION UAS IN THE HOT SHUTDOUN MODE UITH TOTAL CONTROL ROD UITHDRAUAL 0*. AN EVENT LIST IS LACKING FROM 1818 TO 1900 C1920> HOURS. LOGGED VALUES ARE LACKING FROM 1624 TO 1900 C 1920S HOURS. DURING SCHEDULED REVISION 10, A PERFORMANCE-IMPROVING MEASURE UAS INTRODUCED THAT INVOLVED AN INCREASE OF THE SPOOLING LIMITS. DURING SCHEDULE REVISION 11, CONTROL SEQUENCES UERE USED UHICH DID NOT TAKE THIS CHANGE INTO ACCOUNT, UHEREBY THE SPOOLING LIMITS UERE A FACTOR OF 5 TOO LARGE. UHEN AN EVENT SHOUER >> 1500 EVENTS/30 MINUTES OCCURRED, THIS MEANT THAT THE TCP FILE UAS FILLED, LEADING TO SYSTEM STOPPAGE. ON 1985-03-09, THE CORRECT SPOOLING LIMITS UERE ENTERED UITH THE AID
- 30 -
OF UPDATED CONTROL SEQUENCES. AFTER SCHEDULE REVISION >i, A SIHULATED PEAK LOAD TEST C1500 SIGNALS/30 MINUTES) UAS RUN, UHICH THE SYSTEM PASSED SATISFACTORILY. SINCE THE "LIVE" EVENT OF 1985-03-07 PROBABLY INVOLVED I1ORE EVENTS, THE PEAK LOAD TESTS UILL BE RUN IN THE FUTURE UITH 2000-2500 EVENTS/30 MINUTES. A NEU PEAK LOAD TEST IS SCHEDULED FOR 1985-03-11 TO VERIFY THAT THE ABOVE MEASURE HAS HAD THE INTENDED EFFECT.
F3-RO-014/85 - SYSTEM 861 FIRE FIGHTING UATER SYSTEM
LEAKING COOLANT PIPE
TYPE: 101 202 309 409 504 603 703 803 904
EXTERNAL LEAKAGE DISCOVERED ON COOLANT LINE TO OIL COOLERFOR FIRE DIESEL, UHICH SHOULD LEAD TO IMPAIRED COOLING OF LUBRICATING OIL. O-RING IN COOLANT CONNECTION BROKEN, CAUSE IMPOSSIBLE TO DETERMINE, PROBABLY INSTALLATION DAMAGE. UORK ORDER AO 18239400 REPAIR INCLUDING REPLACEMENT OF O-RING EXECUTED. UORK CONCLUDED AND PUMP OPERABLE ON 1985-04-03 AT 1830 HOURS. DOUNTIME 52 HOURS.
TOTAL LOSS OF COMPUTER > 30 MIN 2211-2330 HOURS
TYPE: 101 201 304 409 501 611 707 812 909
AT 2211 HOURS, AUTOMATIC CHANGEOVER OCCURRED FROM SYSTEM A TO SYSTEM B. SYSTEM B STARTED UP AS THE NEU MAIN SYSTEM, UHEREBY THE VISUAL DISPLAY TERMINAL SYSTEM, AND AS IT LATER TURNED OUT THE DATA COLLECTION SYSTEM AS UELL, DID NOT UORK. AT 2239 HOURS, SYSTEM A STARTED UP AS THE BACK-UP SYSTEM AND FILE SYNCHRONIZATION UAS BEGUN. BEFORE CHANGEOVER TOOK PLACE TO SYSTEM A, FILE SYNCHRONIZATION UAS ALLOUED TO CONTINUE TO COMPLETION, UHICH TOOK PLACE AT 2203 HOURS. AT 2224 HOURS, SYSTEM B UAS STOPPED, UHEREUPON CHANGEOVER TO SYSTEM A TOOK PLACE. SYSTEM A EXHIBITED NORMAL AND CORRECT COLLECTION AND PRESENTATION FUNCTIONS. THE STATION UAS IN THE COLD SHUTDOUN MODE DURING THE OUTAGE AND THE TOTAL CONTROL ROD UITHDRAUAL UAS 05£. THE FIRST CHANGEOVER FROM A TO B UAS CAUSED BY LOCKING OF TRANSACTION HANDLING. THE REASON FOR THIS LOCKING IS SOME FAULT IN SYSTEM B CUHICH UAS THEN THE BACK-UP?. DATA ARE NOT AVAILABLE TO INDICATE UHICH FAULT UAS PRESENT IN SYSTEM B. FAILURE OF DATA COLLECTION AND VISUAL DISPLAY TERMINAL PRESENTATION MAY BE DUE TO THIS FAULT. IN ORDER TO PREVENT A FAULT IN THE BACK-UP COMPUTER FROM STOPPING THE MAIN COMPUTER IN THIS UAY, CORRECTIVE ACTIONS UILL BE ADOPTED TO IMPROVE COMPUTER - COMPUTER COMMUNICATION.
- 31
F3-RO-016/8S - SYSTEM 311 STEAM LINES
LONG CLOSURE TIME ON PILOT VALVE FOR VA3
TYPE: 104 203 312 40S 504 605 701 812 901
IN CONNECTION UITH FUNCTIONAL TESTING OF STEAM ISOLATING VALVES DURING START-UP AFTER BEARING INSPECTION, 311 VA3'S PILOT VALVE UAS FOUND TO HAVE VARYING AND EXCESSIVELY LONG TIMES FOR CLOSURE OF MAIN VALVE VA3. MECHANICAL FAULT CSEE BELOU). PILOT VALVE 311 VA3.V3 REPLACED, FUNCTION-TESTED SATISFAC- TORILY ON 1985-04-30. ALL VALVES UERE SUBSEQUENTLY MODIFIED BY TURNING DOUN THE PILOT DISC IN ORDER TO GET GREATER TOLERANCE AND LOUER FRICTION. IN ADDITION, THE SPRINGS UERE REPLACED UITH 25^ STRONGER SPRINGS AND
INCONEL X750. ALL TESTS CARRIED OUT AFTER THE MODIFICATION HAVE HAD APPROVED RESULTS.
F3-RO-017/85 - SYSTEM 861 FIRE FIGHTING UATER SYSTEM
FAILURE OF RESERVE PUMP TO START UHEN TESTED
TYPE: 106 203 304 409 502 611 707 812 906
IN CONNECTION UITH FUNCTIONAL TEST OF RESERVE PUMP START C861 PB2) , THE PUMP FAILED TO START. MALFUNCTIONING AUTOSTART FUNCTION DUE TO LOCAL BLOCKAGE OF UNDOCUMENTED SELECTOR SUITCH.
INFORMATION ON SELECTOR SUITCH ADDED TO INSTRUCTIONS.
F3-RO-018/85 - SYSTEM 314 RELIEF SYSTEM
VALVE'S CONTROL FUNCTION FAILED IN CONNECTION UITH SS10
DATE:850503 / EL.POUER 600MUE / CATEGORY: 4
TYPE: 106 201 304 409 502 605 707 811 901
IN CONNECTION UITH TSXD CTURBINE TRIP + DUMPING PROHIBITION AS PER REACTOR TRIP REPORT F3-SS-023/655, NORMAL CONTROL UITH VA17 AND VB17 UAS NOT OBTAINED. NOR COULD THE VALVES BE OPERATED MANUALLY. AFTER RESTORATION OF IM AND IS, VA1 AND VB1 COULD BE CLOSED. LOGIC FAULT AND UNMONITORED TORQUE LIMITING EQUIPMENT. VALVE ACTUATORS' LOGIC REBUILT AND SIGNAL MONITORING INTRODUCED.
- 32 -
THE FLCU THROUGH 477 KC712 UAS SHUT OFF
TYPE: 106 201 301 409 503 611 707
A CHECK OF PERSISTENT FAULTS REVEALED THAT 477 KC403 LI HAD BEEN
TRIPPED SINCE 1985-05-10. UHEN INSPECTED, THE VALUE UAS FOUND TO BE CLOSED. THE VALUE UAS OPENED. INCORRECT OPERATIONAL ARRANGEffENT OF FLOU PATH.
OPERATING MODE RESTORED.
LATE-OPENING 314VC1 IN CONNECTION UITH TEST BLOUING
TYPE: 106 203 304 409 502 605 707 812 901 IN CONNECTION UITH TEST BLOUING OF 314 VALUES, 314VC1 DID NOT OPEN UNTIL THE 5TH ATTEMPT. HOREOVLR, LONG TIMES UERE OBTAINED DURING THE FIRST BLOUING ON THREE VALVES 314VB1, VB3 AND VC1 . THE AVERAGE TI11E FOR ALL UALVES DURING THE FIRST BLOUING UAS 0.723 S. AFTER AN ADDITIONAL BLOUING UITH 314VC1 AND THREE BLOUING UITH 314VB1 AND VB3, APPROVED TIMES UERE OBTAINED. 314VC1 FAILED TO OPEN ON THE FIRST FOUR ATTEI1PTS OUING TO THE FACT THAT THE IMPULSE SIGNAL UAS CORRECTLY INTERRUPTED AFTER 0.320, 0.356, 0.310 AND 0.422 S AND PILOT VALVE VC12 UAS KEPT OPEN FOR 1.235, 1.194, 1.082 AND 1.220 SECONDS, UHICH UAS NOT A LONG ENOUGH TII1E TO OPEN MAIN VALVE VC1 . ON THE FIFTH ATTEMPT, A 5IGNAL UAS ISSUED LASTING 2.510 SECONDS, WHEREUPON VC1 OPENED AFTER 2.902 SECONDS AFTER INITIATION OF SIGNAL. THE CAUSE FOR NON-OPENING OF VC1 IS TOO SHORT A MANUAL SIGNAL DURATION C0.310-0.422 S) AND THE FACT THAT PILOT VALVE VC12 RECEIVED A CLOSE ORDER BEFORE UC1 HAD TI11E TO OPEN. VCl'S SLOU REACTION HAY BE DUE TO COND^WSATE ACCUHULATION IN THE SERVO SECTION. CORRECTIVE ACTION UAS TAKEN ON THE VALVES IN ACCORDANCE UITH A SEPARATE PROGRAM THAT UAS REPORTED TO THE OPERATIONS MEETING. THE HA IN VALVES' DISCS HAVE BEEN DRILLED FOR BETTER DRAINAGE AND A DECISION HAS BEEN TAKEN TO REBUILD THE DRAINAGE FUNCTION.
F3-RO-021/85 - SYSTEM 311 STEAM LINES
311 VA3.V1 FAILED TO CLOSE UPON MANUAL CLOSE ORDER
TYPE: 103 201 304 409 502 605 707 812 901
UPON DESCENT TO COLD SHUTDOUN REACTOR, 311 ISOLATING VALVES UERE CLOSED MANUALLY. 311 VA3.V1 FAILED TO CLOSE UPON OPENING OF PILOT VALVE VA3.V3, AND DID NOT CLOSE UNTIL 311 VA151 HAD BEEN CLOSED. STICKING PILOT VALVE.
THE PILOT VALUES C8> HAVE BEEN MODIFIED BY TURNING DOUN THE STEM TO
- 33 -
OBTAIN GREATER TOLERANCE AND LESS FRICTION. SPRINGS REPLACED UITH SPRINGS OF ANOTHER MATERIAL AND GREATER SPRING FORCE.
F3-RO-022/85 - SYSTEM 311 STEAM LINES
311 VC3 DID NOT CLOSE UPON I1ANUAL CLOSE ORDEfc DURING TEST 407
DATE: 850520 / EL.POUER 770 11UE / CATEGORY: 3
TYPE: 106 203 304 409 503 605 707 812 901
DURING TEST 407, 311 VC3 UAS SUPPOSED TO CLOSE MANUALLY. THIS DID NOT OCCUR. VALUE STUCK. 311 VC3 CLOSED BY TAPPING ON VC3.V3 AT 1415 HOURS ON 1985-05-20.
PILOT VALUES C8> MODIFIED IN ACCORDANCE UITH FINAL F3-RO-021/85.
F3-RO-023/85 - SYSTEI1 551 STEAM LINE RADIATION MONITORING
MEASURING POINT SHOUED UNREASONABLY LOU VALUE
DATE:850527 / EL.POUER 1000 MU / CATEGORY: 3
TYPE: 106 201 306 409 502 611 701 811 902
IN CONNECTION UITH OPERATION MONITORING, IT UAS DISCOVERED THAT 551KB701 SHOUED AN ABNORMAL VALUE, NO ALARMS ACTIVATED. 314VA/VB17 DID NOT REGULATE AFTER SS10. F3-RO-018/85. FAULT IN HIGH-VOLTAGE UNIT. REPLACEHENT OF HIGH-VOLTAGE UNIT CARRIED OUT ON 1985-05-27.
F3-RO-024/85 - SYSTEM 327 AUXILIARY FEED-UATER SYSTEM
UB2 FAILED TO OPEN IN CONNECTION UITH DISAPPEARING LI IN REACTOR VESSEL
TYPE: 103 201 306 409 504 611 707
IN CONNECTION UITH REACTOR TRIP DURING TEST 459, LOAD SHEDDING, AND LOU LEVEL IN REACTOR VESSEL, 327VB2 FAILED TO OPEN UHEN LI DISAPPEARED. PUMPING-IN INTERRUPTED BY MANUALLY CCENTRALLY) OPENING VB2. FAULT ON PRINTED-CIRCUIT CARD IN LOGIC FOR 327 VB2. PRINTED-CIRCUIT CARD REPLACED. CORRECT FUNCTION TESTED AND VERIFIED ON 1985-06-15 AT 0100 HOURS.
- 34 -
F3-KO-025/85 - "SYSTEM 654 STAND-BY POUER PLANT CONTROL EQUIPMENT
SPEED nONITORING EQUIPMENT OUT OF ORDER
DATE:650618 / EL. POUER 1050 MU / CATEGORY: 3
TYPE: 106 202 306 409 501 611 707 811 909
DURING AN INSPECTION ROUND, IT UAS DISCOVERED THAT THE SPEED MONITORING EQUIPMENT UAS OUT OF ORDER. DG320 INOPERABLE. FAULT IN SUPPLY DEVICE TO THE DEUTA EQUIPMENT CAUSED BY A TEMPORARY OVERLOAD IN THE ELECTRONICS, LEADING TO DIS- CONNECTION OF THE RECTIFIER, UHICH IS THE SUPPLY DEVICE TO THE DIESEL'S DEUTA EQUIPMENT. DEUTA = DIESEL'S IN- TERNAL AUTOMATIC EQUIPMENT. ELECTRONIC ROCKER SUITCH RESET. DIESEL TEST-RUN UITH SATISFACTORY RESULTS. MEASUREMENT OF CURRENT SETTING FOR PROTECTIVE DEVICE. THE DIESEL'S DEUTA EQUIPMENT UILL BE CHECKED AFTER EVERY DIESEL RUN. REDUCTION OH THE SUPPLY DEVICE'S LOAD HAS BEEN CARRIED OUT.
F3-RO-026/85 - SYSTEM 221 CONTROL ROD DRIVES
IN CONNECTION UITH REACTOR TRIP DUE TO MANUAL ACTIVATION OF IS (OPERATING ORDER 79/85), CONTROL ROD AH40 STUCK IN THE BB'4, UITHDRAUN POSITION
TYPE: 103 201 303 409 502 611 702 812
CONTROL ROD AH40 STUCK IN THE 96* UITHDRAUN POSITION IN CONNECTION UITH REACTOR TRIP. A DETACHED SLIDE PLATE ON THE CONTROL ROD HAD GOTTEN STUCK IN THE CONTROL ROD DRIVE, PREVENTING INSERTION. CONTROL ROD DRIVE REPLACED. ALL CONTROL ROD'S SLIDE PLATES CHECKED.
Ol-RO-001/85 - SYSTEM 677 CONVERTER SYSTEM
CONVERTER
TYPE: 106 201 301 409 502 608 704 812 909
ALARM FOR HIGH FREQUENCY C50.5 HZ). THE CONVERTER COULD NOT BE BROUGHT DOUN FROM 50.6 HZ. DG111 UAS STARTED, PARALLELLED AND SECTIONED OFF FROM THE MAIN GRID. STANDBY SUPPLY FROM THE DIE5EL-P0UERED GRID UAS CONNECTED TO A0.2S1. DRIFT IN REFERENCE VOLTAGE DEVICE. ADJUSTED ACTUAL VALUE TO REGULATOR. CONVERTER VERIFIED AS BEING j £ TO OPERATE BETUEEN 48.4 AND 50.8 HZ. THE REFERENCE VOLTAGE DEVICE UILL BE REPLACED. TOTAL DOUNTIME: 16 H.
- 35 -
EARTH FAULT ON BUSBAR 678 AO,1 IS SI, S2
DATE .-8503 17 / EL. POUER 465 HUE / CATEGORY: 3
TYPE: 106 201 301 409 504 605 707 809 909
EARTH FAULT ON ONE OF THE CONTROL VALUES FOR 321 V2. THE VALVE IS SPRING-CLOSING AND IS OPERATED VIA A CONTROL VALVE GROUP CONNECTED IN 2-0F-3 LOGrc. N SOI1E OF THE STRANDS IN THE CONTROL LEAD UERE IN CONTACT UITH THE CASING AT THE TERMINAL POST FOR ONE OF THE CONTROL COILS.
CONTROL LEAD CONNECTED IN CORRECT MANNER C85-01-23).
Ol-RO-003/85 - SYSTEM 679 OTHER DC SYSTEMS
EARTH FAULT ON BUSBAR 679 110 V DC S6
TYPE: 104 201 301 409 504 605 707 809 909
EARTH FAULT ON 311 Vl:09 LIMIT SUITCH FOR OPEN INDICATION. THE EARTH FAULT OCCURRED AS A RESULT OF MOISTURE ENTERING THE LIMIT SUITCH DUE TO LEAKAGE FROM 311 VI. THE FAULT DIS- APPEARED UHEN THE MOISTURE HAD DRIED OFF. THE OPEN INDICATION FROM 311 Vl:09 UAS 5HUNTED OUT FOR 7 HOURS, AFTER UHICH THE EARTH FAULT HAD DISAPPEARED AND THE SHUNT UAS REMOVED.
Ol-RO-004/85 - SYSTEM 642 230V AC SUITCHGEAR CMANUALLY GASTURBINE-FUSED
)
TYPE: 106 201 301 401 502 609 702 812 909
UPON CHANGEOVER FROM T12 TO Til, LOSS OF VOLTAGE UAS OBTAINED ON B6 AND UNDERLYING BUSBARS. THE CIRCUIT BREAKER B6-S OPENED SPURIOUSL? 70 MS AFTER CLOSURE. THIS UAS PROBABLY DUE TO CONTACT REBOUND. TRIAL OPERATION OF THE CIRCUIT BREAKER DID NOT REVEAL ANY FAULTS. TESTING OF THE OUTPUT SIGNALS TO THE CIRCUIT BREAKER FROM THE RELAY CIRCUITS DID NOT INDICATE ANY FAULTS. FOR PREVENTIVE PURPOSES, THE CIRCUIT BREAKER UAS REPLACED UITH A SPARE UNIT AND THE TEMPERATURE IN THE ROOM UAS INCREASED. THE REPLACED CIRCUIT BREAKER HAS BEEN TESTED VIA 15 CLOSINGS AND OPENINGS UITHOUT ANY FAULT HAVING BEEN FOUND.
- 36 -
Ol-RO-005/85 - SYSTEM 742 AUXILIARY BUILDING VENTILATION SYSTEM
REDUCED FUNCTION OF EMERGENCY VENTILATION SYSTEM
DATE:850130 / EL.POUER 465 nUE / CATEGORY: 3
TYPE: 106 203 303 40P 502 611 701 812 909
ON AN OPERATING ROUND, AIR LEAKAGE UAS DISCOVERED THROUGH THE PILOT VALVE FOR 742 V21. THIS LED TO FUNCTIONAL TESTING OF THE EMERGENCY VENTILATION SYSTEM, UHICH REVEALED THAT THE DAMPER 742 V21 UAS NOT CLOSING COMPLETELY. MECHANICAL SLUGGISHNESS OF DAMPER ARM AND MAIN VALUE. 1 PILOT VALVE REPLACED 2 EXERCISING OF DACIPER FUNCTION. REPAIR TIME 7
HOURS 3 THE MAIN CYLINDER UILL BE REPLACED AT THE NEXT OPPORTUNITY
Ol-RO-006/85 - SYSTEM 351 BORON INJECTION SYSTEM (BUR>
ELEVATED BORON CONTENT IN 351 Tl
TYPE: 106 209 312 409 506 611 704 812 909
ON 1985-01-23, AN ANALYSIS UAS MADE OF THE BORON CONCENTRATION, SHOUING TOO LOU BORON CONCENTRATION. BORON UAS ADDED ON THE SAME DAY IN ORDER TO

report on safety related occurrences and reactor trips

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