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{{#Wiki_filter:F'RIORIY'Y IACCELER.ATED RIDS PROC!%SIX REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:9410270363 DOC.DATE: 94/10/17 NOTARIZED: | {{#Wiki_filter:F'RIORIY'Y IACCELER.ATED RIDS PROC! %SIX REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS) | ||
NO FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G AUTH.NAME AUTHOR AFFILIATION ST MARTIN,J.T. | ACCESSION NBR:9410270363 DOC.DATE: 94/10/17 NOTARIZED: NO DOCKET N FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION ST MARTIN,J.T. Rochester Gas & Electric Corp. | ||
Rochester Gas&Electric Corp.MECREDY,R.C. | MECREDY,R.C. Rochester Gas & Electric Corp. | ||
Rochester Gas&Electric Corp.RECIP.NAME RECIPIENT AFFILIATION | RECIP.NAME RECIPIENT AFFILIATION | ||
==SUBJECT:== | ==SUBJECT:== | ||
LER 94-010-00:on 940916,volt bus 12B inadvertenly tripped.Caused by defective procedure. | LER 94-010-00:on 940916,volt bus 12B inadvertenly tripped. | ||
Normal power supple.es restored | Caused by defective procedure. Normal power supple.es restored "B" emeregency diesel generator stopped | ||
05000244 RECIPIENT ID CODE/NAME PD1-3 PD INTERNAL AEOD/~GAB/DSQ XHXF~02 NRR/DE/EMEB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DSSA/SPLB NRR/PMAS/IRCB-E RGN1 FILE 01 EXTERNAL: EG&G BRYCE,J.H NOAC MURPHY 1 G A | & & aligned for auto standby.W/941017 ltr. | ||
PLEASE HELP L!S TO REDUCE iVASTE!CONTACTTIIE DOCL'iIEiTCOiTROL DESK, ROOXI PI-37 (EXT, 504-2033)TO | DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE: | ||
FULL TEXT CONVERSXON REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26 | TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc. | ||
NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-3 PD 1 1 JOHNSON,A 1 1 INTERNAL AEOD/~GAB/DSQ 2 2 AEOD/SPD/RRAB 1 1 XHXF~02 1 1 NRR/DE/EELB 1 1' NRR/DE/EMEB l. 1 NRR/DORS/OEAB 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRSS/PRPB 2 2 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NRR/PMAS/IRCB-E 1 1 RES/DSIR/EIB 1 1 RGN1 FILE 01 1 1 EXTERNAL: EG&G BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 NOAC MURPHY 1 G A 1 1 NOAC POORE,W. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 N | |||
VOTE TO ALL"Rl DS" RECIPIENTS: | |||
PLEASE HELP L!S TO REDUCE iVASTE! CONTACTTIIE DOCL'iIEiTCOiTROL DESK, ROOXI PI-37 (EXT, 504-2033 ) TO ELIilliATEVOL'R RAMIE PROil DISTRIBL'TIOiLIS'I'S I'OR DOCL'iIEi'I'S 5'OL'Oi "I'L'I'.I)! | |||
FULL TEXT CONVERSXON REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26 | |||
' | ' | ||
r | 10ec r | ||
~89 EAST AVENUE, ROCHESTER N.Y.f4649-000f ROBERT C.MECREDY Vice President Ginned Nuclear Production | StAIC ROCHESTER GAS AND ELECTRIC CORPORATION ~ 89 EAST AVENUE, ROCHESTER N.Y. f4649-000f ROBERT C. MECREDY TELEPHOME Vice President AAEACQM 716 546 2700 Ginned Nuclear Production October 17, 1994 UPS. Nuclear Regulatory Commission Document Control Desk Attn: Allen R. Johnson PWR Project Directorate I-3 Washington, D.C. 20555 | ||
==Subject:== | ==Subject:== | ||
LER 94-010, Loss of 4160 Volt Bus 12B, Due to Defective Procedure, Results in Automatic Start of"B" Emergency Diesel Generator R.E.Ginna Nuclear Power Plant Docket No.50-244 In accordance with 10 CFR 50.73, Licensee Event Report System, item (a)(2)(iv), which requires a report of,"any event or condition that resulted in a manual or"automatic actuation of any engineered safety feature (ESF), including the reactor protection system (RPS)", the attached Licensee Event Report LER 94-010 is hereby submitted. | LER 94-010, Loss of 4160 Volt Bus 12B, Due to Defective Procedure, Results in Automatic Start of "B" Emergency Diesel Generator R.E. Ginna Nuclear Power Plant Docket No. 50-244 In accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (iv), which requires a report of, "any event or condition that resulted in a manual or"automatic actuation of any engineered safety feature (ESF), including the reactor protection system (RPS)", the attached Licensee Event Report LER 94-010 is hereby submitted. | ||
This event has in no way affected the public's health and safety.Very truly yours, Robert C.Mecredy xc: U.S.Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna USNRC Senior Resident Inspector 9410270363 941017 PDR ADOCK 05000244 S PDR NRC FORH 366 | This event has in no way affected the public's health and safety. | ||
Very truly yours, Robert C. Mecredy xc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna USNRC Senior Resident Inspector 9410270363 941017 PDR ADOCK 05000244 S PDR | |||
This event is NUREG-1022 Cause Code (D).Corrective action to preclude repetition is outlined in Section V.B.HRC FORM 366 (5-92) | NRC FORH 366 U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150 ~ 0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY HITH THIS IHFORHATION COLLECTION REQUEST: 50.0 HRS. | ||
NRC FORH 366A | LICENSEE EVENT REPORT (LER) FORHARD COMMENTS REGARDIHG BURDEN ESTIHATE TO THE INFORMATION AND RECORDS HANAGEMENT BRANCH (HNBB 7714), U.ST NUCLEAR REGULATORY COHHISSION ~ | ||
o September 16, 1994, 1018 EDST: Event date and time.o September 16, 1994, 1018 EDST: Discovery date and time.o September 16, 1994, 1018 EDST: Control Room operators verify the"B" Emergency Diesel Generator (D/G)operation and safeguards buses 16 and 17 energized. | (See reverse for required number of digits/characters for each block) llASHIHGTON, DC 20555-0001, AND TO THE PAPERNORK REDUCTION PROJECT (3150-0104), OFFICE OF HANAGEMENT AND BUDGET WASHINGTON DC 20503. | ||
o September 16, 1994, 1120 EDST: Circuit 751 declared operable at the completion of maintenance and testing.o September 16, 1994, 1125 EDST: Safeguards buses 16 and 17 were resupplied from Circuit 751.o September 16, 1994, 1142 EDST: The"B" Emergency D/G was stopped and realigned for auto standby.NRC FORM 366A (5-92) | FACILITY NAME (1) R. E. Ginna Nuclear Power Plant DOCKET NUHBER (2) PAGE (3) 05000244 10F 10-TITLE (4) Loss of 4160 Volt Bus 12B, Due to Defective Procedure, Results in Automatic Start of "B" Emergency Diesel Generator EVENT DATE (5) LER NUHBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) | ||
SEQUENTIAL REVISION FACILITY HAHE DOCKET NUHBER MONTH DAY YEAR YEAR MONTH DAY YEAR HUHBER NUHBER 09 16 94 94 --010-- 00 10 17 94 FACILITY HAHE DOCKET HUHBER OPERATING THIS REPORT IS SUBHITTED PURSUANT TO THE RE UIREHENTS OF 10 CFR 5: (Check one or mor e) (11) | |||
HODE (9) N 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b) | |||
PNER 20.405(a )(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.71 (c) | |||
LEVEL (10) 20.405(a)(1)(ii) 50.36(c)(2) 50 '3(a)(2)(vii) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) (Specify in 20 '05(a)(1)(iv) 50.73(a)(2)(ii) 50 73(a) (2) (vi i i ) (0) Abstract below | |||
~ | |||
and in Text, 20.405(a)(1)(v) 50.73(a)(2)(III) 50.73(a)(2)(x) NRC Form 366A) | |||
LICENSEE CONTACT FOR THIS LER (12) | |||
NAME John T. St. Martin - Director, Operating Experience TELEPHONE HUHBER (Include Area Code) | |||
(315) 524-4446 COMPLETE ONE LINE FOR EACH COHPONENT FAILURE DESCRIBED IN THIS REPORT (13) | |||
REPORTABLE REPORTABLE CAUSE SYSTEH COHPONENT HANUFACTURER CAUSE SYSTEM COHPONENT HANUFACTURER TO HPRDS TO NPRDS SUPPLEHENTAL REPORT EXPECTED (14) EXPECTED HOHTH DAY YEAR YES SUBHISS ION (lf yes, complete EXPECTED SUBHISSION DATE). | |||
X NO DATE (15) | |||
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) | |||
On September 16, 1994, at approximately 1018 EDST, with the reactor at approximately 98% steady state power, the 4160 Volt circuit breaker that was supplying power to 4160 Volt bus 12B was inadvertently tripped. This resulted in deenergization of bus 12B and momentary loss of power to uBn train 480 Volt safeguards buses 16 and 17. | |||
The nBn Emergency Diesel Generator started and reenergized buses 16 and 17, as per design. | |||
The underlying cause of the inadvertent circuit breaker trip was a defective procedure. This event is NUREG-1022 Cause Code (D). | |||
Corrective action to preclude repetition is outlined in Section V.B. | |||
HRC FORM 366 (5-92) | |||
NRC FORH 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY 'NITN THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. | |||
FORMARD COMHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (MNBB 7T14), U.S. NUCLEAR REGULATORY COHHISSION, llASNINGTON, DC 20555 0001 AND TO THE PAPERISRK REDUCTION PROJECT (3140.0104), OFFICE OF MANAGEMENT AND BUDGET llASHINGTON DC 20503. | |||
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) | |||
YEAR SEQUENT IAL REVISION R.E. Ginna Nuclear Power Plant 05000244 2 OF 10 94 010 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) | |||
PRE-EVENT PLANT CONDITIONS The plant was at approximately 98% steady state reactor power, with no major operational activities in progress. All offsite power to 4160 Volt buses 12A and 12B was being supplied from Circuit 767 (34.5 KV offsite power source). Circuit 767 was supplying power through 34.5 KV to 4160 Volt transformer 12B (12B transformer), via 4160 Volt circuit breakers 52/12BY (to bus 12A) and 52/12BX (to bus 12B). (See the attached sketch of the offsite power distribution system.) 34.5 KV to 4160 Volt transformer 12A (12A transformer), | |||
which is .supplied from Circuit 751 (34.5 KV offsite power source), | |||
was deenergized and declared inoperable to permit previously scheduled maintenance and testing of the 12A transformer and associated circuit breakers. | |||
At the time of this event, trip testing was in progress on 4160 Volt circuit breaker 52/12AX (alternate power supply from the 12A transformer to bus 12B), in accordance with Maintenance Procedure PME-50-04-52/12AX, "Bus 12B Alternate Power Source." Plant electricians had just notified the Control Room operators that circuit breaker 12AX would be closed while in the "test" position. | |||
II. DESCRIPTION OF EVENT A. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES: | |||
o September 16, 1994, 1018 EDST: Event date and time. | |||
o September 16, 1994, 1018 EDST: Discovery date and time. | |||
o September 16, 1994, 1018 EDST: Control Room operators verify the "B" Emergency Diesel Generator (D/G) operation and safeguards buses 16 and 17 energized. | |||
o September 16, 1994, 1120 EDST: Circuit 751 declared operable at the completion of maintenance and testing. | |||
o September 16, 1994, 1125 EDST: Safeguards buses 16 and 17 were resupplied from Circuit 751. | |||
o September 16, 1994, 1142 EDST: The "B" Emergency D/G was stopped and realigned for auto standby. | |||
NRC FORM 366A (5-92) | |||
NRC FORM 366A | NRC FORM 366A U.S. NKLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY lllTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. | ||
The Control Room operators observed that bus 12B had deenergized and displayed zero (0)voltage, because the circuit breaker supplying power to bus 12B had tripped.The loss of power to bus 12B resulted in undervoltage on safeguards'buses 16 and 17, and the"B" Emergency D/G started and reenergized these buses, as per design.When the scheduled maintenance and testing was completed on the 12A transformer and associated breakers, the Control Room operators cleared the holds on Circuit 751 and th'e 12A transformer. | FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE IHFORHATION AND RECORDS HANAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140.0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503. | ||
A switching order was used to restore Circuit 751, 12A transformer, and associated breakers to operable status.34.5 KV circuit breaker 75112 was closed, energizing the 12A transformer. | FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) | ||
The Control Room operators directed plant electricians to investigate the failure, and there were no anomalies noted.At approximately 1120 EDST, using Equipment Restoration procedure ER-ELEC.1 (Restoration of Offsite Power), the Control Room operators closed circuit breaker 12AX, energizing bus 12B from the 12A transformer. | YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 3 OF 10 94 -- 010-- 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) | ||
At approximately 1125 EDST,"B" train safeguards buses 16 and 17 were resupplied by offsite power, via Circuit 751 | B. EVENT: | ||
On September 16, 1994, at approximately 1018 EDST, with the reactor at approximately 98~ steady state full power, the Control Room received numerous annunciator alarms. The Control Room operators immediately determined that 4160 Volt bus 12B was deenergized, that "B" train 480 Volt safeguards buses 16 and 17 had lost their power supply from bus 12B, and that the "B" Emergency D/G had started and was tied to safeguards buses 16 and 17. | |||
The Control Room operators immediately performed the appropriate actions of Abnormal Procedure AP-ELEC.1 (Loss of 12A And/Or 12B Transformer) to stabilize the plant, and verified that the "B" Emergency D/G was operating properly and that safeguards buses 16 and 17 were energized. The Control Room operators observed that bus 12B had deenergized and displayed zero (0) voltage, because the circuit breaker supplying power to bus 12B had tripped. The loss of power to bus 12B resulted in undervoltage on safeguards'buses 16 and 17, and the "B" Emergency D/G started and reenergized these buses, as per design. | |||
When the scheduled maintenance and testing was completed on the 12A transformer and associated breakers, the Control Room operators cleared the holds on Circuit 751 and th'e 12A transformer. A switching order was used to restore Circuit 751, 12A transformer, and associated breakers to operable status. 34.5 KV circuit breaker 75112 was closed, energizing the 12A transformer. | |||
The Control Room operators directed plant electricians to investigate the failure, and there were no anomalies noted. At approximately 1120 EDST, using Equipment Restoration procedure ER-ELEC.1 (Restoration of Offsite Power), the Control Room operators closed circuit breaker 12AX, energizing bus 12B from the 12A | |||
't transformer. | |||
At approximately 1125 EDST, "B" train safeguards buses 16 and 17 were resupplied by offsite power, via Circuit 751 approximately 1142 EDST, September 16, 1994, the "B" Emergency D/G was stopped and realigned for auto standby. | |||
NRC FORM 366A (5-92), | |||
NRC FORM 366A | NRC FORM 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150 ~ 0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPOHSE TO COHPLY WITH THIS INFORHAT ION COLLECTION REQUEST: 50.0 HRS. | ||
FORWARD COMHENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORHATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COMHISSION, WASHIHGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503. | |||
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUMBER (6) PAGE (3) | |||
YEAR SEOUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 4 OF 10 010 00 TEXT (tf more space is required, use additional copies of NRC Form 366A) (17) | |||
C. I NOPERABLE STRUCTURES i COMPONENTS i OR SYSTEMS THAT CONTR BUTED TO I THE EVENT: | |||
Circuit 751 was inoperable for scheduled maintenance of the 12A transformer, beginning at approximately 0717 EDST on September 15, 1994, and was restored to service at approximately 1120 EDST on September 16, 1994.. | |||
D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED: | |||
The momentary loss of power caused a loss of program memory for radiation monitor terminal RCT-1 and associated channels R-12A (Containment ventilation effluent), R-14A (Plant ventilation ef fluent), R-31 (>>A>> steam line monitor), and R-32 (B>> steam line monitor) . | |||
E. METHOD OF DISCOVERY: | |||
This event was immediately apparent due to Main Control Board alarms and indications in the Control Room when bus 12B was deenergized. | This event was immediately apparent due to Main Control Board alarms and indications in the Control Room when bus 12B was deenergized. | ||
These included Main Control Board annunciators J-5 (gll or gl2 Transformer Out of Synch), J-6 (4KV Main or Tie Breaker Trip), J-7 (480 V Main or Tie Breaker Trip), J-8 (480V MCC Supply Breaker Trip), and L-28 (12B XFMR or 12B Bus Trouble).F.OPERATOR ACTION: Following the undervoltage condition on buses 16 and 17, the>>B>>Emergency D/G automatically started and energized these buses.The Control Room operators immediately performed the appropriate actions and verified that the>>B>>Emergency D/G was operating properly, and that safeguards buses 16 and 17 were energized.'he Control Room operators cleared the holds on Circuit 751, restored offsite power to buses 16 and 17, stopped the>>B>>Emergency D/G, and realigned it for auto standby.HRC FORM 366A (5-92) | These included Main Control Board annunciators J-5 (gll or gl2 Transformer Out of Synch), J-6 (4KV Main or Tie Breaker Trip), J-7 (480 V Main or Tie Breaker Trip), J-8 (480V MCC Supply Breaker Trip), and L-28 (12B XFMR or 12B Bus Trouble). | ||
N NRC FORH 366A | F. OPERATOR ACTION: | ||
Following the undervoltage condition on buses 16 and 17, the >>B>> | |||
The>>B>>Emergency D/G automatically started due to the undervoltage condition on buses 16 and 17, displayed proper voltage and frequency and closed into safeguards buses 16 and 17 to supply emergency power.III.CAUSE OF EVENT IMMEDIATE CAUSE: The automatic actuation of the.>>B>>Emergency D/G was due to undervoltage on safeguards buses 16 and 17.B.INTERMEDIATE CAUSE: The undervoltage on safeguards buses 16 and 17 was due to bus 12B being deenergized when circuit breaker 12BX tripped due to an electrical interlock. | Emergency D/G automatically started and energized these buses. The Control Room operators immediately performed the appropriate actions and verified that the >>B>> Emergency D/G was operating properly, and that safeguards buses 16 and 17 were energized.'he Control Room operators cleared the holds on Circuit 751, restored offsite power to buses 16 and 17, stopped the >>B>> Emergency D/G, and realigned it for auto standby. | ||
C.ROOT CAUSE: The underlying cause of the tripping of circuit breaker 12BX was a defective procedure. | HRC FORM 366A (5-92) | ||
During development of this procedure (PME-50-04-52/12AX), the switch development of an elementary wiring diagram (EWD)was not used as a reference in determining post-maintenance operability testing.The procedure is for preventive maintenance of Model P-51000 POWL-VAC metal-clad switchgear, manufactured by Powell Electrical Mfg.Co.There is a normally open>>s>>contact (52S/12AX) in the trip circuit for breaker 12BX that comes from breaker 12AX, to prevent both 4160 Volt circuit breakers (12AX and 12BX)from being closed simultaneously. | |||
Contact 52S/12AX is located in the mechanism-operated cell (MOC)switch of these'ircuit breakers.These>>s>>contacts change state with movement of the breaker mechanism. | N NRC FORH 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATION COLLECTIOH REQUEST: 50.0 HRS. | ||
Technical reviewers incorrectly assumed that the cell switch would not function when in"test", and therefore concluded that with breaker 12AX in"test", contact 52S/12AX would not close.NRC FORM 366A (5-92) | FORWARD COHHEHTS REGARDIHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORHATION .AHD RECORDS HANAGEMEHT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COHHISSIOH ~ | ||
'WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3110.0104), OFF ICE OF MAHAGEHEHT AHD BUDGET WASHINGTON DC 20503. | |||
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3) | |||
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 5 OF 10 94 010 00 TEXT (If more space is required, use additionaI copies of HRC Form 366A) (17) | |||
At approximately 1354 EDST on September 16, 1994, the Shift Supervisor notified the NRC per 10 CFR 50.72 (b) (2) (ii) . | |||
,SAFETY SYSTEM RESPONSES: | |||
The >>B>> Emergency D/G automatically started due to the undervoltage condition on buses 16 and 17, displayed proper voltage and frequency and closed into safeguards buses 16 and 17 to supply emergency power. | |||
III. CAUSE OF EVENT IMMEDIATE CAUSE: | |||
The automatic actuation of the .>>B>> Emergency D/G was due to undervoltage on safeguards buses 16 and 17. | |||
B. INTERMEDIATE CAUSE: | |||
The undervoltage on safeguards buses 16 and 17 was due to bus 12B being deenergized when circuit breaker 12BX tripped due to an electrical interlock. | |||
C. ROOT CAUSE: | |||
The underlying cause of the tripping of circuit breaker 12BX was a defective procedure. During development of this procedure (PME-50-04-52/12AX), the switch development of an elementary wiring diagram (EWD) was not used as a reference in determining post-maintenance operability testing. The procedure is for preventive maintenance of Model P-51000 POWL-VAC metal-clad switchgear, manufactured by Powell Electrical Mfg. Co. | |||
There is a normally open >>s>> contact (52S/12AX) in the trip circuit for breaker 12BX that comes from breaker 12AX, to prevent both 4160 Volt circuit breakers (12AX and 12BX) from being closed simultaneously. Contact 52S/12AX is located in the mechanism-operated cell (MOC) switch of these'ircuit breakers. These >>s>> | |||
contacts change state with movement of the breaker mechanism. | |||
Technical reviewers incorrectly assumed that the cell switch would not function when in "test", and therefore concluded that with breaker 12AX in "test", contact 52S/12AX would not close. | |||
NRC FORM 366A (5-92) | |||
NRC FORM 366A U.S. NUCLEAR REGULATORY COHHISSIOH APPROVED BY OHB NO. 3150-0104 (5-92) EXP I RES 5/31/95 EST IHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. | |||
FORWARD COHHEHTS REGARD IHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AHD RECORDS HAHAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.ST NUCLEAR REGULATORY COHHISSIOH, WASHINGTON, DC 20555-0001 AHD TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET 'WASHIHGTON DC 20503. | |||
FACILITY NAHE (1) DOCKET NUMBER (2) LER NUHBER (6) PAGE 3) | |||
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 6 OF 10 94 -- 010-- pp | |||
~y TEXT (If more space is required, use additional copies of HRC Form 366A) (17) | |||
There is another contact in series with the 52S/12AX contact that operates from the synchronizing switch for the circuit breaker. | |||
This contact is closed when the synch switch is in the "Off" position. When reviewing the EWD, technical reviewers misinterpreted the function of this contact, and assumed that the contact was closed when the synch switch was in the "On" position. | |||
Thus, the trip logic for circuit breaker 12BX was made up when the synch switch was in the "Off" position as soon as breaker 12AX closed, causing breaker 12BX to trip per design. | |||
After further investigation, it was discovered that this same incorrect interpretation of switch contact status was made for circuit breakers 12AX, 12AY, and 12BY. There were a total of eight defective procedures, one preventive and one corrective maintenance procedure for each of the four circuit breakers. | |||
This event is NUREG-1022 Cause Code (D), Defective Procedure. | |||
This loss of power meets the NUMARC 93-01, "Industry Gui'deline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants", definition of a "Maintenance Preventable Functional Failure". | |||
IV. ANALYSIS OF EVENT: | |||
This event is reportable in accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (iv), which requires a report of, "any event or condition that resulted in a manual or automatic actuation of any engineered safety feature (ESF), including the reactor protection system (RPS)", in that the starting of the "B" Emergency D/G was an automatic actuation of an ESF system. | |||
HRC FORM 366A (5-92) | |||
NRC FORH 366A UPS. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. | |||
FORWARD COHHENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MAHAGEHEHT BRANCH TEXT CONTINUATION (HHBB 7714), U.ST NUCLEAR REGULATORY COHHISSION, WASHINGTOH, DC 20555-0001 AHD TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503. | |||
FACILITY NAME (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3) | |||
YEAR'EQUENTIAL REVISION R.E. Ginna Nuclear Power 'Plant 05000244 7 OF 10 94 010 00 TEXT (If more space is required, use additional copies of HRC Form 366A) (17) | |||
An assessment was performed considering both the safety consequences and implications of this event with the following results and conclusions: | |||
o All reactor control and protection systems performed as designed. | |||
o Circuit breaker 12BX operated as designed and tripped when it received a valid trip signal. | |||
o The "B" Emergency D/G operated as designed by starting and supplying emergency power to safeguards buses 16 and 17. | |||
o Circuit 767 was still in operation supplying power to the "A" train safeguards buses; subsequently Circuit 751 was lined up to supply power to the "B" train safeguards buses as permitted by plant technical specifications. | |||
o Radiation monitors R-12A and R-14A are redundant to monitors R-12 and R-14. R-12 and R-14 remained operable during this event. | |||
o Loss of radiation monitors R-31 and R-32 is compensated for by local monitoring of steam line radiation, which would be performed by plant personnel, as specified in emergency operating procedures. | |||
Based on the above, safety wa's assured at all times. | |||
it can be concluded that the public's health and V. CORRECTIVE ACTION A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS: | |||
o Safeguards buses 16 and 17 normal power supplies were restored via Circuit 751, and the "B" Emergency D/G was stopped and aligned for auto standby. | |||
o Circuit breaker 12BX was cycled to confirm that the breaker responded as designed. | |||
o The RCT-1 radiation monitor terminal and associated channels R-12A, R-14A, R-31, and R-32 were reprogrammed and declared operable. | |||
HRC FORH 366A (5-92) | |||
NRC FORH 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150-0104 (5-92) EXP I RES 5/31/95 ESTIHATED BURDEN PER RESPOHSE TO COHPLY MITH THIS INFORHATION COLLECTIOH REQUEST: 50.0 HRS. | |||
FORHARD COHHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORHATIOH AND RECORDS HANAGEHEHT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, HASHINGTOH, DC 20555-0001 AND TO THE PAPERHORK REDUCTION PROJECT (3180-0104), OFFICE OF HANAGEHENT AND BUDGET MASHINGTON DC 20503. | |||
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3) | |||
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 8 OF 10 94 -- 010-- 00 TEXT (If more space is required, use additional copies of HRC Form 366A) (17) | |||
B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE: | |||
o All Corrective Maintenance Electrical (CME), Preventive Maintenance Electrical (PME), and Protective Relay (PRI) procedures associated with Powell circuit breakers were quarantined. This included PME-50-04-52/12AX and the seven other procedures for circuit breakers 12AX, 12AY, 12BX, and 12BY. | |||
o The quarantined procedures will be reviewed against the EWDs and drawing conventions to determine interpretation of switch contact status were made during if any other errors in procedure development. Quarantined procedures that are found to be in error will be revised. | |||
o A Training Work Request (TWR) has been submitted to incorporate details of this event during Industry Events training, emphasize event details during maintenance training on Preferred Power Sources, and reinforce the requirement to use switch development information during training on EWDs. | |||
o Electrical Engineering has evaluated the design of the offsite power configuration, and has recommended a method to avoid 4160 Volt circuit breaker trips during breaker testing. | |||
o The causes and effects of loss of power to the RCT-1 radiation monitor terminal will be reviewed, to determine the need for changes in design or maintenance of the system. | |||
HRC FORH 366A (5-92) | |||
NRC FORH 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150.0104 (5-92) EXP I RES 5/31/95 l | |||
ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS IHFORHATION COLLECTIOH REQUEST: 50.0 HRS ~ | |||
FORWARD COHHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORHATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140 0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503. | |||
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3) | |||
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 9 OF 10 010-- 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) | |||
VI. ADDITIONAL INFORMATION A. FAILED COMPONENTS: | |||
None B. PREVIOUS LERs ON SIMILAR EVENTS: | |||
A similar LER event historical search was conducted with the following results: No documentation of similar LER events with the'same root cause at Ginna Nuclear Power Plant could be iden-tified. However, LERs 91-002 and 92-007 were similar events (start of a D/G due to loss of 4160 Volt bus or offsite power) with different root causes. | |||
C. SPECIAL COMMENTS: | |||
None NRC FORM 366A (5-92) | |||
NRC | NRC FORN 366A U.S. NUCLEAR REGULATORY CONNISSION APPROVEO BY ONB NO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY MITH THIS INFORHATION COLLECTION REQUEST: 50.0 HRS. | ||
FORMARD COHHENTS REGARDING BURDEN ESTINATE TO L1CENSEE EVENT REPORT (LER) THE INFORNATIOH AHD RECORDS IIANAGEHENT BRANCH TEXT CONTINUATION (NHBB 7714)1 U.S. NUCLEAR REGULATORY CONHISSIONI MASHINGTON, DC 20555-0001 AND .TO THE PAPERMORK REDUCTIOH PROJECT (3140.0104)1 OFFICE OF HANAGENENT AND BUDGET MASHINGTON DC 20503. | |||
FACILITY NAHE (1) DOCKET NUHBER (2) NUHBER (6 PAGE (3) | |||
YEAR SEQUENT IAL REVISION R.E. Ginna Nuclear Power Plant 10'ER 05000244 94 pp 10 OF 010 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) | |||
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$ 2/ WSI I/2$ $ lit NO 1$ IC 17 COIN NO CO HRC FORN 366A (5-92)}} |
Revision as of 17:18, 29 October 2019
ML17263A811 | |
Person / Time | |
---|---|
Site: | Ginna |
Issue date: | 10/17/1994 |
From: | Mecredy R, St Martin J ROCHESTER GAS & ELECTRIC CORP. |
To: | Andrea Johnson NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
References | |
LER-94-010, LER-94-10, NUDOCS 9410270363 | |
Download: ML17263A811 (17) | |
Text
F'RIORIY'Y IACCELER.ATED RIDS PROC! %SIX REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9410270363 DOC.DATE: 94/10/17 NOTARIZED: NO DOCKET N FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION ST MARTIN,J.T. Rochester Gas & Electric Corp.
MECREDY,R.C. Rochester Gas & Electric Corp.
RECIP.NAME RECIPIENT AFFILIATION
SUBJECT:
LER 94-010-00:on 940916,volt bus 12B inadvertenly tripped.
Caused by defective procedure. Normal power supple.es restored "B" emeregency diesel generator stopped
& & aligned for auto standby.W/941017 ltr.
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:
TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.
NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-3 PD 1 1 JOHNSON,A 1 1 INTERNAL AEOD/~GAB/DSQ 2 2 AEOD/SPD/RRAB 1 1 XHXF~02 1 1 NRR/DE/EELB 1 1' NRR/DE/EMEB l. 1 NRR/DORS/OEAB 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRSS/PRPB 2 2 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NRR/PMAS/IRCB-E 1 1 RES/DSIR/EIB 1 1 RGN1 FILE 01 1 1 EXTERNAL: EG&G BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 NOAC MURPHY 1 G A 1 1 NOAC POORE,W. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 N
VOTE TO ALL"Rl DS" RECIPIENTS:
PLEASE HELP L!S TO REDUCE iVASTE! CONTACTTIIE DOCL'iIEiTCOiTROL DESK, ROOXI PI-37 (EXT, 504-2033 ) TO ELIilliATEVOL'R RAMIE PROil DISTRIBL'TIOiLIS'I'S I'OR DOCL'iIEi'I'S 5'OL'Oi "I'L'I'.I)!
FULL TEXT CONVERSXON REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26
'
10ec r
StAIC ROCHESTER GAS AND ELECTRIC CORPORATION ~ 89 EAST AVENUE, ROCHESTER N.Y. f4649-000f ROBERT C. MECREDY TELEPHOME Vice President AAEACQM 716 546 2700 Ginned Nuclear Production October 17, 1994 UPS. Nuclear Regulatory Commission Document Control Desk Attn: Allen R. Johnson PWR Project Directorate I-3 Washington, D.C. 20555
Subject:
LER 94-010, Loss of 4160 Volt Bus 12B, Due to Defective Procedure, Results in Automatic Start of "B" Emergency Diesel Generator R.E. Ginna Nuclear Power Plant Docket No. 50-244 In accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (iv), which requires a report of, "any event or condition that resulted in a manual or"automatic actuation of any engineered safety feature (ESF), including the reactor protection system (RPS)", the attached Licensee Event Report LER 94-010 is hereby submitted.
This event has in no way affected the public's health and safety.
Very truly yours, Robert C. Mecredy xc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna USNRC Senior Resident Inspector 9410270363 941017 PDR ADOCK 05000244 S PDR
NRC FORH 366 U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150 ~ 0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY HITH THIS IHFORHATION COLLECTION REQUEST: 50.0 HRS.
LICENSEE EVENT REPORT (LER) FORHARD COMMENTS REGARDIHG BURDEN ESTIHATE TO THE INFORMATION AND RECORDS HANAGEMENT BRANCH (HNBB 7714), U.ST NUCLEAR REGULATORY COHHISSION ~
(See reverse for required number of digits/characters for each block) llASHIHGTON, DC 20555-0001, AND TO THE PAPERNORK REDUCTION PROJECT (3150-0104), OFFICE OF HANAGEMENT AND BUDGET WASHINGTON DC 20503.
FACILITY NAME (1) R. E. Ginna Nuclear Power Plant DOCKET NUHBER (2) PAGE (3) 05000244 10F 10-TITLE (4) Loss of 4160 Volt Bus 12B, Due to Defective Procedure, Results in Automatic Start of "B" Emergency Diesel Generator EVENT DATE (5) LER NUHBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)
SEQUENTIAL REVISION FACILITY HAHE DOCKET NUHBER MONTH DAY YEAR YEAR MONTH DAY YEAR HUHBER NUHBER 09 16 94 94 --010-- 00 10 17 94 FACILITY HAHE DOCKET HUHBER OPERATING THIS REPORT IS SUBHITTED PURSUANT TO THE RE UIREHENTS OF 10 CFR 5: (Check one or mor e) (11)
HODE (9) N 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)
PNER 20.405(a )(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.71 (c)
LEVEL (10) 20.405(a)(1)(ii) 50.36(c)(2) 50 '3(a)(2)(vii) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) (Specify in 20 '05(a)(1)(iv) 50.73(a)(2)(ii) 50 73(a) (2) (vi i i ) (0) Abstract below
~
and in Text, 20.405(a)(1)(v) 50.73(a)(2)(III) 50.73(a)(2)(x) NRC Form 366A)
LICENSEE CONTACT FOR THIS LER (12)
NAME John T. St. Martin - Director, Operating Experience TELEPHONE HUHBER (Include Area Code)
(315) 524-4446 COMPLETE ONE LINE FOR EACH COHPONENT FAILURE DESCRIBED IN THIS REPORT (13)
REPORTABLE REPORTABLE CAUSE SYSTEH COHPONENT HANUFACTURER CAUSE SYSTEM COHPONENT HANUFACTURER TO HPRDS TO NPRDS SUPPLEHENTAL REPORT EXPECTED (14) EXPECTED HOHTH DAY YEAR YES SUBHISS ION (lf yes, complete EXPECTED SUBHISSION DATE).
X NO DATE (15)
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
On September 16, 1994, at approximately 1018 EDST, with the reactor at approximately 98% steady state power, the 4160 Volt circuit breaker that was supplying power to 4160 Volt bus 12B was inadvertently tripped. This resulted in deenergization of bus 12B and momentary loss of power to uBn train 480 Volt safeguards buses 16 and 17.
The nBn Emergency Diesel Generator started and reenergized buses 16 and 17, as per design.
The underlying cause of the inadvertent circuit breaker trip was a defective procedure. This event is NUREG-1022 Cause Code (D).
Corrective action to preclude repetition is outlined in Section V.B.
HRC FORM 366 (5-92)
NRC FORH 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY 'NITN THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.
FORMARD COMHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (MNBB 7T14), U.S. NUCLEAR REGULATORY COHHISSION, llASNINGTON, DC 20555 0001 AND TO THE PAPERISRK REDUCTION PROJECT (3140.0104), OFFICE OF MANAGEMENT AND BUDGET llASHINGTON DC 20503.
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)
YEAR SEQUENT IAL REVISION R.E. Ginna Nuclear Power Plant 05000244 2 OF 10 94 010 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
PRE-EVENT PLANT CONDITIONS The plant was at approximately 98% steady state reactor power, with no major operational activities in progress. All offsite power to 4160 Volt buses 12A and 12B was being supplied from Circuit 767 (34.5 KV offsite power source). Circuit 767 was supplying power through 34.5 KV to 4160 Volt transformer 12B (12B transformer), via 4160 Volt circuit breakers 52/12BY (to bus 12A) and 52/12BX (to bus 12B). (See the attached sketch of the offsite power distribution system.) 34.5 KV to 4160 Volt transformer 12A (12A transformer),
which is .supplied from Circuit 751 (34.5 KV offsite power source),
was deenergized and declared inoperable to permit previously scheduled maintenance and testing of the 12A transformer and associated circuit breakers.
At the time of this event, trip testing was in progress on 4160 Volt circuit breaker 52/12AX (alternate power supply from the 12A transformer to bus 12B), in accordance with Maintenance Procedure PME-50-04-52/12AX, "Bus 12B Alternate Power Source." Plant electricians had just notified the Control Room operators that circuit breaker 12AX would be closed while in the "test" position.
II. DESCRIPTION OF EVENT A. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES:
o September 16, 1994, 1018 EDST: Event date and time.
o September 16, 1994, 1018 EDST: Discovery date and time.
o September 16, 1994, 1018 EDST: Control Room operators verify the "B" Emergency Diesel Generator (D/G) operation and safeguards buses 16 and 17 energized.
o September 16, 1994, 1120 EDST: Circuit 751 declared operable at the completion of maintenance and testing.
o September 16, 1994, 1125 EDST: Safeguards buses 16 and 17 were resupplied from Circuit 751.
o September 16, 1994, 1142 EDST: The "B" Emergency D/G was stopped and realigned for auto standby.
NRC FORM 366A (5-92)
NRC FORM 366A U.S. NKLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY lllTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.
FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE IHFORHATION AND RECORDS HANAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140.0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503.
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 3 OF 10 94 -- 010-- 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
B. EVENT:
On September 16, 1994, at approximately 1018 EDST, with the reactor at approximately 98~ steady state full power, the Control Room received numerous annunciator alarms. The Control Room operators immediately determined that 4160 Volt bus 12B was deenergized, that "B" train 480 Volt safeguards buses 16 and 17 had lost their power supply from bus 12B, and that the "B" Emergency D/G had started and was tied to safeguards buses 16 and 17.
The Control Room operators immediately performed the appropriate actions of Abnormal Procedure AP-ELEC.1 (Loss of 12A And/Or 12B Transformer) to stabilize the plant, and verified that the "B" Emergency D/G was operating properly and that safeguards buses 16 and 17 were energized. The Control Room operators observed that bus 12B had deenergized and displayed zero (0) voltage, because the circuit breaker supplying power to bus 12B had tripped. The loss of power to bus 12B resulted in undervoltage on safeguards'buses 16 and 17, and the "B" Emergency D/G started and reenergized these buses, as per design.
When the scheduled maintenance and testing was completed on the 12A transformer and associated breakers, the Control Room operators cleared the holds on Circuit 751 and th'e 12A transformer. A switching order was used to restore Circuit 751, 12A transformer, and associated breakers to operable status. 34.5 KV circuit breaker 75112 was closed, energizing the 12A transformer.
The Control Room operators directed plant electricians to investigate the failure, and there were no anomalies noted. At approximately 1120 EDST, using Equipment Restoration procedure ER-ELEC.1 (Restoration of Offsite Power), the Control Room operators closed circuit breaker 12AX, energizing bus 12B from the 12A
't transformer.
At approximately 1125 EDST, "B" train safeguards buses 16 and 17 were resupplied by offsite power, via Circuit 751 approximately 1142 EDST, September 16, 1994, the "B" Emergency D/G was stopped and realigned for auto standby.
NRC FORM 366A (5-92),
NRC FORM 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150 ~ 0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPOHSE TO COHPLY WITH THIS INFORHAT ION COLLECTION REQUEST: 50.0 HRS.
FORWARD COMHENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORHATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COMHISSION, WASHIHGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503.
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUMBER (6) PAGE (3)
YEAR SEOUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 4 OF 10 010 00 TEXT (tf more space is required, use additional copies of NRC Form 366A) (17)
C. I NOPERABLE STRUCTURES i COMPONENTS i OR SYSTEMS THAT CONTR BUTED TO I THE EVENT:
Circuit 751 was inoperable for scheduled maintenance of the 12A transformer, beginning at approximately 0717 EDST on September 15, 1994, and was restored to service at approximately 1120 EDST on September 16, 1994..
D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:
The momentary loss of power caused a loss of program memory for radiation monitor terminal RCT-1 and associated channels R-12A (Containment ventilation effluent), R-14A (Plant ventilation ef fluent), R-31 (>>A>> steam line monitor), and R-32 (B>> steam line monitor) .
E. METHOD OF DISCOVERY:
This event was immediately apparent due to Main Control Board alarms and indications in the Control Room when bus 12B was deenergized.
These included Main Control Board annunciators J-5 (gll or gl2 Transformer Out of Synch), J-6 (4KV Main or Tie Breaker Trip), J-7 (480 V Main or Tie Breaker Trip), J-8 (480V MCC Supply Breaker Trip), and L-28 (12B XFMR or 12B Bus Trouble).
F. OPERATOR ACTION:
Following the undervoltage condition on buses 16 and 17, the >>B>>
Emergency D/G automatically started and energized these buses. The Control Room operators immediately performed the appropriate actions and verified that the >>B>> Emergency D/G was operating properly, and that safeguards buses 16 and 17 were energized.'he Control Room operators cleared the holds on Circuit 751, restored offsite power to buses 16 and 17, stopped the >>B>> Emergency D/G, and realigned it for auto standby.
HRC FORM 366A (5-92)
N NRC FORH 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATION COLLECTIOH REQUEST: 50.0 HRS.
FORWARD COHHEHTS REGARDIHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORHATION .AHD RECORDS HANAGEMEHT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COHHISSIOH ~
'WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3110.0104), OFF ICE OF MAHAGEHEHT AHD BUDGET WASHINGTON DC 20503.
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3)
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 5 OF 10 94 010 00 TEXT (If more space is required, use additionaI copies of HRC Form 366A) (17)
At approximately 1354 EDST on September 16, 1994, the Shift Supervisor notified the NRC per 10 CFR 50.72 (b) (2) (ii) .
,SAFETY SYSTEM RESPONSES:
The >>B>> Emergency D/G automatically started due to the undervoltage condition on buses 16 and 17, displayed proper voltage and frequency and closed into safeguards buses 16 and 17 to supply emergency power.
III. CAUSE OF EVENT IMMEDIATE CAUSE:
The automatic actuation of the .>>B>> Emergency D/G was due to undervoltage on safeguards buses 16 and 17.
B. INTERMEDIATE CAUSE:
The undervoltage on safeguards buses 16 and 17 was due to bus 12B being deenergized when circuit breaker 12BX tripped due to an electrical interlock.
C. ROOT CAUSE:
The underlying cause of the tripping of circuit breaker 12BX was a defective procedure. During development of this procedure (PME-50-04-52/12AX), the switch development of an elementary wiring diagram (EWD) was not used as a reference in determining post-maintenance operability testing. The procedure is for preventive maintenance of Model P-51000 POWL-VAC metal-clad switchgear, manufactured by Powell Electrical Mfg. Co.
There is a normally open >>s>> contact (52S/12AX) in the trip circuit for breaker 12BX that comes from breaker 12AX, to prevent both 4160 Volt circuit breakers (12AX and 12BX) from being closed simultaneously. Contact 52S/12AX is located in the mechanism-operated cell (MOC) switch of these'ircuit breakers. These >>s>>
contacts change state with movement of the breaker mechanism.
Technical reviewers incorrectly assumed that the cell switch would not function when in "test", and therefore concluded that with breaker 12AX in "test", contact 52S/12AX would not close.
NRC FORM 366A (5-92)
NRC FORM 366A U.S. NUCLEAR REGULATORY COHHISSIOH APPROVED BY OHB NO. 3150-0104 (5-92) EXP I RES 5/31/95 EST IHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.
FORWARD COHHEHTS REGARD IHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AHD RECORDS HAHAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.ST NUCLEAR REGULATORY COHHISSIOH, WASHINGTON, DC 20555-0001 AHD TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET 'WASHIHGTON DC 20503.
FACILITY NAHE (1) DOCKET NUMBER (2) LER NUHBER (6) PAGE 3)
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 6 OF 10 94 -- 010-- pp
~y TEXT (If more space is required, use additional copies of HRC Form 366A) (17)
There is another contact in series with the 52S/12AX contact that operates from the synchronizing switch for the circuit breaker.
This contact is closed when the synch switch is in the "Off" position. When reviewing the EWD, technical reviewers misinterpreted the function of this contact, and assumed that the contact was closed when the synch switch was in the "On" position.
Thus, the trip logic for circuit breaker 12BX was made up when the synch switch was in the "Off" position as soon as breaker 12AX closed, causing breaker 12BX to trip per design.
After further investigation, it was discovered that this same incorrect interpretation of switch contact status was made for circuit breakers 12AX, 12AY, and 12BY. There were a total of eight defective procedures, one preventive and one corrective maintenance procedure for each of the four circuit breakers.
This event is NUREG-1022 Cause Code (D), Defective Procedure.
This loss of power meets the NUMARC 93-01, "Industry Gui'deline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants", definition of a "Maintenance Preventable Functional Failure".
IV. ANALYSIS OF EVENT:
This event is reportable in accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (iv), which requires a report of, "any event or condition that resulted in a manual or automatic actuation of any engineered safety feature (ESF), including the reactor protection system (RPS)", in that the starting of the "B" Emergency D/G was an automatic actuation of an ESF system.
HRC FORM 366A (5-92)
NRC FORH 366A UPS. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.
FORWARD COHHENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MAHAGEHEHT BRANCH TEXT CONTINUATION (HHBB 7714), U.ST NUCLEAR REGULATORY COHHISSION, WASHINGTOH, DC 20555-0001 AHD TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503.
FACILITY NAME (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3)
YEAR'EQUENTIAL REVISION R.E. Ginna Nuclear Power 'Plant 05000244 7 OF 10 94 010 00 TEXT (If more space is required, use additional copies of HRC Form 366A) (17)
An assessment was performed considering both the safety consequences and implications of this event with the following results and conclusions:
o All reactor control and protection systems performed as designed.
o Circuit breaker 12BX operated as designed and tripped when it received a valid trip signal.
o The "B" Emergency D/G operated as designed by starting and supplying emergency power to safeguards buses 16 and 17.
o Circuit 767 was still in operation supplying power to the "A" train safeguards buses; subsequently Circuit 751 was lined up to supply power to the "B" train safeguards buses as permitted by plant technical specifications.
o Radiation monitors R-12A and R-14A are redundant to monitors R-12 and R-14. R-12 and R-14 remained operable during this event.
o Loss of radiation monitors R-31 and R-32 is compensated for by local monitoring of steam line radiation, which would be performed by plant personnel, as specified in emergency operating procedures.
Based on the above, safety wa's assured at all times.
it can be concluded that the public's health and V. CORRECTIVE ACTION A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:
o Safeguards buses 16 and 17 normal power supplies were restored via Circuit 751, and the "B" Emergency D/G was stopped and aligned for auto standby.
o Circuit breaker 12BX was cycled to confirm that the breaker responded as designed.
o The RCT-1 radiation monitor terminal and associated channels R-12A, R-14A, R-31, and R-32 were reprogrammed and declared operable.
HRC FORH 366A (5-92)
NRC FORH 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150-0104 (5-92) EXP I RES 5/31/95 ESTIHATED BURDEN PER RESPOHSE TO COHPLY MITH THIS INFORHATION COLLECTIOH REQUEST: 50.0 HRS.
FORHARD COHHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORHATIOH AND RECORDS HANAGEHEHT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, HASHINGTOH, DC 20555-0001 AND TO THE PAPERHORK REDUCTION PROJECT (3180-0104), OFFICE OF HANAGEHENT AND BUDGET MASHINGTON DC 20503.
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3)
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 8 OF 10 94 -- 010-- 00 TEXT (If more space is required, use additional copies of HRC Form 366A) (17)
B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:
o All Corrective Maintenance Electrical (CME), Preventive Maintenance Electrical (PME), and Protective Relay (PRI) procedures associated with Powell circuit breakers were quarantined. This included PME-50-04-52/12AX and the seven other procedures for circuit breakers 12AX, 12AY, 12BX, and 12BY.
o The quarantined procedures will be reviewed against the EWDs and drawing conventions to determine interpretation of switch contact status were made during if any other errors in procedure development. Quarantined procedures that are found to be in error will be revised.
o A Training Work Request (TWR) has been submitted to incorporate details of this event during Industry Events training, emphasize event details during maintenance training on Preferred Power Sources, and reinforce the requirement to use switch development information during training on EWDs.
o Electrical Engineering has evaluated the design of the offsite power configuration, and has recommended a method to avoid 4160 Volt circuit breaker trips during breaker testing.
o The causes and effects of loss of power to the RCT-1 radiation monitor terminal will be reviewed, to determine the need for changes in design or maintenance of the system.
HRC FORH 366A (5-92)
NRC FORH 366A U.S. NUCLEAR REGULATORY COHHISSION APPROVED BY OHB NO. 3150.0104 (5-92) EXP I RES 5/31/95 l
ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS IHFORHATION COLLECTIOH REQUEST: 50.0 HRS ~
FORWARD COHHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORHATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140 0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503.
FACILITY NAHE (1) DOCKET NUHBER (2) LER NUHBER (6) PAGE (3)
YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 9 OF 10 010-- 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
VI. ADDITIONAL INFORMATION A. FAILED COMPONENTS:
None B. PREVIOUS LERs ON SIMILAR EVENTS:
A similar LER event historical search was conducted with the following results: No documentation of similar LER events with the'same root cause at Ginna Nuclear Power Plant could be iden-tified. However, LERs91-002 and 92-007 were similar events (start of a D/G due to loss of 4160 Volt bus or offsite power) with different root causes.
C. SPECIAL COMMENTS:
None NRC FORM 366A (5-92)
NRC FORN 366A U.S. NUCLEAR REGULATORY CONNISSION APPROVEO BY ONB NO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY MITH THIS INFORHATION COLLECTION REQUEST: 50.0 HRS.
FORMARD COHHENTS REGARDING BURDEN ESTINATE TO L1CENSEE EVENT REPORT (LER) THE INFORNATIOH AHD RECORDS IIANAGEHENT BRANCH TEXT CONTINUATION (NHBB 7714)1 U.S. NUCLEAR REGULATORY CONHISSIONI MASHINGTON, DC 20555-0001 AND .TO THE PAPERMORK REDUCTIOH PROJECT (3140.0104)1 OFFICE OF HANAGENENT AND BUDGET MASHINGTON DC 20503.
FACILITY NAHE (1) DOCKET NUHBER (2) NUHBER (6 PAGE (3)
YEAR SEQUENT IAL REVISION R.E. Ginna Nuclear Power Plant 10'ER 05000244 94 pp 10 OF 010 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
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