ML17264A147

LER 95-007-00:on 950803,lost Power from 34.5 Kv Offsite Power Circuit 751 Due to Offsite Electrical Storm,Resulting in Automatic Start of EDG B.Offsite Power Restored,Edg B Stopped & Realigned & Circuit 751 cleared.W/950901 Ltr

ML17264A147
Person / Time
Site:	Ginna
Issue date:	09/01/1995
From:	Mecredy R, St Martin J ROCHESTER GAS & ELECTRIC CORP.
To:	Andrea Johnson NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-95-007, LER-95-7, NUDOCS 9509070205
Download: ML17264A147 (13)

Text

IpRIORITY 3.

(ACCELERATED RZDS PROCESSING)

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9509070205 DOC.DATE: 95/09/01 NOTARIZED: NO DOCKET g FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 P AUTH. NAME AUTHOR AFFILIATION ST MARTIN,J.T. Rochester Gas & Electric Corp.

MECREDY,R.C. Rochester Gas & Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION J OHNSON,A.R.

SUBJECT:

LER 95-007-00:on 950803,lost power from 34.5 kV offsite 0 ower Circuit 751 due to offsite electrical'torm, resulting n automatic start of EDG B.Offsite power restored,EDG B stopped & realigned & Circuit 751 cleared.W/950901 ltr.

R DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTRl Event Report (LER),

ENCL 1 Incident SIZE: !

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l TITLE: 50.73/50.9 Licensee NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 T RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-1 PD 1 1 JOHNSON,A 1 INTERNAL: AE~O/SZD/~B 2 2 AEOD/SPD/RRAB 1 1

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N NOTE TO ALL "RZDS" RECIPIENTS:

CONTROL PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT FROM DESK, ROOM OWFN 5D8 (415-2083) TO ELIMINATE YOUR NAME DISTRIBUTION .LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26

AND ROCHESTER GAS AND ElECTRTC CORPORATTON + 89 EASTAVENUE, ROCHESTER, M Y 14649.0001 AREA CODE 716 54'6-27N ROBERT C. MECREDY Vice President Nvcleor Operotions September 1, 1995 U.S. Nuclear Regulatory Commission Document Control Desk Attn: Allen R. Johnson PWR Project Directorate I-1 Washington, D.C. 20555

Subject:

LER 95-007, Loss of 34.5 KV Offsite Power Circuit 751, Due to Offsite Electrical Storm, 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 95-007 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 Mr. Allen R. Johnson (Mail Stop 14B2)

PWR Project Directorate I-1 Washington, D.C. 20555 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 U.S. NRC Ginna Senior Resident Inspector t . (E <~

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950'9070205 9'50'st01 PDR ADOCK 05000244

HRC FORM 366 U.S. NUCLEAR REGULATORY IXNHISSIOH APPROVED BY N5/31/953150-0104 EXPIRES HO.

(5-92)

ESTIHATED BURDEH PER RESPONSE TO COHPLY WITH THIS INFORHATION COLLECTIOH REQUEST: 50.0 HRS.

LICENSEE EVENT REPORT (LER) FOR'WARD COMMENTS REGARDING BURDEN ESTIHATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, (See reverse for required number of digits/characters for each block) WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION" PROJECT (3180 0104), OFFICE OF HAHAGEHEHT AND BUDGET WASHINGTON DC 20503.

FAGILITY NAME (1) R. E. Ginna Nuclear Power Plant DOCKET NNIBER 05000244 (2) PAGE (3) 10F 10 TITLE (4) Loss of 34.5 KV Offsite PoMer Circuit 751, Due to Offsite Electrical Storm, Results in Automatic Start of <<B<<

Emergency Diesel Generator EVEHT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (S)

SEQUENTIAL REVISION FACILITY HAHE DOCKET NUMBER HOHTH DAY YEAR YEAR MONTH DAY YEAR NUMBER NUHBER

.08 03 95 95 --007-- 00 09 01 FACILITY NAME DOCKET HUMBER OPERATING THIS REPORT IS SUBHITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5. (Check one or more) (11)

H(NE (9) N 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71 (b)

POWER 20 405(a )(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c) 097 50.73(a)(2)(vii)

LEVEL (10) 20.405(a)(l)(ii) 50.36(c)(2) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) (Specify in 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Abstract below and in Text, 20.405(a)(1)(v) 50 '3(a)(2)(iii) 50.73(a)(2)(x) HRC Form 366A)

LICENSEE CONTACT FOR THIS LER (12)

HAME John T. St. Martin - Technical Assistant TELEPHONE NUMBER (include Area Code)

(716) 771-3641 CNIPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

REPORTABLE REPORTABLE CAUSE SYSTEH COMPONENT HANUFACTURER CAUSE SYSTEH COHPOHENT HANUFACTURER TO NPRDS TO NP)DS EA CBL5 X000 N, SUPPLEHENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR YES SUSHI SSI OH (If yes, complete EXPECTED SUBHISSION DATE).

X HO DATE (15)

ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typegrit ten lines) (16)

On August 3, 1995, at approximately 1526 EDST, with the reactor at approximately 97% steady state power, power from Circuit 751 (34.5 KV offsite power source) was lost. This resulted in deenergization of 4160 Volt bus 12B and "B" train 480 Volt safeguards buses 16 and 17. The "B" Emergency Diesel Generator (D/G) automatically started'nd reenergized buses 16 and 17 as per design. There was no change in reactor power or turbine load.

Immediate corrective action was to perform the appropriate actions of Abnormal Procedure AP-ELEC.1 (Loss of 12A And/Or 12B Busses) to stabilize the plant and to verify that the "B" Emergency D/G had started and reenergized buses 16 and 17.

The cause of the loss of power from Circuit 751 was determined to be electrical storm "C" activity that affected circuits at offsite Station 204 and tripped the phase instantaneous overcurrent protective relay for Circuit 751 (at Station 204), deenergizing the circuit.

This event is NUREG-1022 Cause Code (C).

HRC FORH 366 (5-92)

HRC FORN 366A U.S. NUCLEAR REGULATORY C(NHISSIOH APPROVED BY OIB HO- 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATEO BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATIOH COLLECTION REQUEST: 50.0 COHHEHTS REGARDING BURDEN ESTINATE TO BR'ORWARD LICENSEE EVENT REPORT (LER) THE INFORNATION AND RECORDS HANAGEHENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY C(WNISSION ~

TEXT CONTINUATION WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF NANAGENENT AND BUDGET WASHIHGTON DC 20503-FACILITY HAHE (1) DOCKET NWBER (2) LER NIMBER (6) PAGE (3)

SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 NUHBER HUNBER 2 OF 10

-- 007-- 00 TEXT (lf more space is required, use additional copies of HRC Form 366A) (17)

I. PRE-EVENT PLANT CONDITIONS The plant was at approximately 97% steady state reactor power. The "B" Emergency Diesel Generator (D/G) had been removed from service earlier on August 3 to perform planned maintenance (and had been declared inoperable at 0422 EDST to perform this maintenance). By mid-afternoon on August 3, the maintenance had been completed, but the "B" Emergency D/G was still considered inoperable, pending completion of post-maintenance testing. Due to weather conditions (a

'hunderstorm was in progress in the vicinity of the plant), testing was being deferred until the thunderstorm passed. The Plant Manager recommended that the "B" Emergency D/G be aligned for auto standby (although still inoperable from an administrative viewpoint) to be an available source of power in the event of a "B" loss of offsite power during the thunderstorm. Therefore, the Emergency D/G was aligned for auto standby.

The offsite power configuration to the plant was in the alternate "50% / 50%" offsite power lineup. This configuration uses Circuit 767 (instead of Circuit 751) to supply power to the "A" train of safeguards equipment:

o Circuit 751 (34.5 KV offsite power source) was supplying power to the "B" train 480 Volt safeguards buses 16 and 17 through 34.5 KV to 4160 Volt transformer 12A (12A transformer), via Circuit Breaker 52/12AX, to 4160 Volt bus 12B, and through the safeguards bus 4160 Volt to 480 Volt transformers.

o Circuit 767 (34.5 KV offsite power source) was supplying power to the "A" train 480 Volt safeguards buses 14 and 18 through 34.5 KV to 4160 Volt transformer 12B (12B transformer), via Circuit Breaker 52/12BY, to 4160 Volt bus 12A, and through the safeguards bus 4160 Volt to 480 Volt transformers.

See the attached sketch of the offsite power distribution system.

II. DESCRIPTION OF EVENT A. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES:

o August 3, 1995, 1526 EDST: Event date and time.

August 3, 1995, 1526 EDST: Discovery date and time.

HRC FORN 366A (5-92)

NRC FORH 366A U.S. NUCLEAR REGULATORY CQQII SSIOH APPROVED BY QIB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO CONPLY WITH THIS INFORHATION COLLECTION REQUEST: 50.0 HRS ~

FORWARD CONNENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE IHFORHATION AND RECORDS HANAGEHENT BRANCH TEXT CONTINUATION (HNBB 7714) ~ U.S. NUCLEAR REGULATORY COHNISSIOH ~

WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3150.0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503.

FACILITY NAKE (1) DOCKET NIHIBER (2) LER NQIBER (6 PAGE (3)

SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 NUHBER NUHBER 30F10 95 -- 007-- 00 TEXT (If more space is required, use additional copies of HRC Form 366A) (17)

August 3, 1995, 1526 EDST: Control Room operators "B" Emergency Diesel Generator verify the (D/G) operation and that safeguards buses 16 and 17 are energized.

August 3, 1995, 1628 EDST: Safeguards buses 16 and 17 were transferred to Circuit 767 from the "B" Emergency D/G.

August 3, 1995, 1635 EDST: The "B" Emergency D/G was stopped and realigned for auto standby.

o August 3, 1995, 1644 EDST: Circuit 751 was declared operable.

August 7, 1995, 1228 EDST: Offsite power configuration was restored to the alternate "50% / 50%" lineup.

B. EVENT:

On August 3, 1995, at approximately 1526 EDST, with the reactor at approximately 97% steady state full power, the Control Room received numerous Main Control Board annunciator alarms. Among these alarms were L-20 (12A XFMR OR 12A BUS TROUBLE), J-5 g12 TRANSFORMER OUT OF SYNCH)i J 7 (480V MAIN OR TIE BREAKER (Ill OR TRIP), J-9 (SAFEGUARD BREAKER TRIP), and J-32 (EMERGENCY DIESEL GEN 1B PANEL). The Control Room operators determined that the following events had occurred:

o Circuit 751 (34.5 KV offsite power source) was deenergized o "B" train 480 Volt safeguards buses 16 and 17 had lost their power supply from 4160 Volt bus 12B (buses 16 and 17 had been momentarily deenergized) o The "B" Emergency D/G had automatically started and was tied to safeguards buses 16 and 17 The Control Room operators verified that reactor coolant system temperature and pressure were stable, and that there was no change in reactor power or turbine load. They performed the appropriate actions of Abnormal Procedure AP-ELEC.1 (Loss of 12A And/Or 12B Busses) to stabilize the plant. They verified that the "B" Emergency D/G was operating and that safeguards buses 16 and 17 were energized. The Control Room operators observed that Circuit 751 and bus 12B displayed zero (0) voltage.

NRC FORH 366A (5-92)

NRC FORH 366A U.S. NUCLEAR REGULATORY CQIIISSIOH APPROVED BY QIB NO. 3150-0104 (5-92) EXP I RES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHAT ION COLLECT ION REQUEST: 50.0 HRS.

FORWARD CQDIENTS REGARDING BURDEN EST IHATE TO LICENSEE EVENT REPORT (LER) THE I HFORHAT ION AND RECORDS HANAGEHENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSIOH, TEXT CONTINUATION WASHIHGTOH, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3180-0104) ~ OFFICE OF HANAGEHENT AND BUDGET WASHIHGTOH DC 20503.

FACILITY NAHE (1) DOCKET NWER (2) LER NWBER (6) PAGE (3)

SEQUENTIAL REVISION YEAR R.E. Ginna Nuclear Power Plant NUMBER NUNBER 05000244 95 007-- 00 4 OF 10 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

The loss of power from Circuit 751 resulted "B" in undervoltage on safeguards buses 16 and 17, and the Emergency D/G automatically started within ten (10) seconds as per design and reenergized these buses.

Energy Operations personnel also identified the loss of power from Circuit 751, and promptly notified Ginna Control Room operators of. the loss of power from Circuit 751, which appeared to be caused by an offsite lightning strike that affected Circuit 751.

The Control Room operators referred to Equipment Restoration procedure ER-ELEC.1 (Restoration of Offsite Power) to restore offsite power to 4160 Volt bus 12B and 480 Volt safeguards buses 16 and 17. The Control Room operators closed 4160 Volt circuit breaker 52/12BX to energize bus 12B from Circuit 767, via the 12B transformer, at approximately 1602 EDST. At approximately 1628 EDST, safeguards buses 16 and 17 were transferred to Circuit 767 from the "B" Emergency D/G. (Circuit 767 had remained in operation, supplying "A" train 480 Volt safeguards buses 14 and 18, throughout the event.)

At approximately 1635 EDST, August 3; 1995, the "B" Emergency D/G was stopped and realigned for auto standby, pending performance of the post-maintenance testing.

Energy Operations subsequently contacted the Control Room operators and confirmed that the loss of power from Circuit 751 was caused by electrical storm activity that affected circuits at offsite Station 204 and tripped the "C" phase instantaneous overcurrent protective relay for Circuit 751 (at Station 204),

deenergizing the circuit. Relays had been reset at Station 204, and Circuit 751 was reenergized and declared operable at approximately 1644 EDST.

Circuit 751 was not immediately 'lined up to supply plant loads, but was maintained as the plant's backup supply of offsite power rather than realigning the electrical system during the thunderstorm conditions.

C. INOPERABLE STRUCTURES, COMPONENTS'R SYSTEMS THAT CONTRIBUTED TO THE EVENT:

None NRC FORH 366A (5-92)

NRC FORM 366A U.S NUCLEAR REGULATORY COMMISSION APPROVEO BY QNI NO. 3150-0104 (5-92) EXP I RES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY MITH THIS INFORMATION COLLECTIOH REQUEST: 50 0 HRS.

FORMARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MAHAGEMEHT BRANCH (MMBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, TEXT CONTINUATION NASHIHGTOH, DC 20555-0001 AND TO THE PAPERMORK REDUCTION PROJECT (3180-0104), OFFICE OF MANAGEMENT AND BUDGET iJASHINGTON DC 20503.

FACILITY MANE (1) DOCKET NQIBER (2) LER NIBIBER (6) PAGE (3)

SEQUENTIAL REVISION YEAR R.E. Ginna Nuclear Power Plant 05000244 NUMBER NUMBER 5OF 10

-- 007-- 00 TEXT (If more space is required, use additional copies of MRC Form 366A) (17)

D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:

The thunderstorm conditions also affected some. telephone service.

At approximately 1539 EDST, the Emergency Notification System (ENS) line for Ginna Station became inoperable. The Shift Technical Advisor notified the NRC Operations Center and the USNRC Ginna Senior Resident Inspector of the loss of the ENS at approximately 1544 EDST. (The ENS was subsequently restored to operable status at approximately 1401 EDST on August 4.)

E. METHOD OF DISCOVERY:

This event was immediately apparent due to numerous Main Control Board alarms and other indications in the Control Room when power from Circuit 751 was lost.

F. OPERATOR ACTION:

Following'he undervoltage condition on buses '16 and 17, the "B" Emergency D/G automatically started and reenergized these buses.

The Control Room operators performed the appropriate actions to verify that the "B" Emergency D/G was operating and safeguards buses 16 and 17 were energized.

The Control Room operators manually restarted the "B" and "C" containment recirculation fans, which had tripped due to the loss of bus 16.

The momentary loss of power to buses 16 and 17 caused the trip of the common sample pump for monitoring of the containment (CNMT) atmosphere by channels R-10A (iodine), R-11 (particulate) and R-12 (noble gas). The Control Room operator manually restarted the common sample pump at approximately 1535 EDST.

The Control Room operators restored offsite power (from Circuit 767) to buses 16 and 17, stopped the "B" Emergency D/G, and realigned testing of it the for auto standby, prior to starting post-maintenance D/G.

Subsequently, the Shift Supervisor notified the NRC at approximately 1748 EDST per 10 CFR 50.72 (b) (2) (ii), non-emergency four hour notification.

HRC FORM 366A (5-92)

NRC FORH.366A U.S. NUCLEAR REGULATORY COHHISSIOH APPROVED BY OHB HO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPOHSE TO COHPLY WITH THIS INFORHATIOH COLLECTION REQUEST: 50.0 HRS.

FORWARD COHHENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORHATIOH AND RECORDS NANAGEHENT BRANCH (HNBB 7714), U.S. HUCLEAR REGULATORY COHHISSIOH, TEXT CONTINUATION 'WASHINGTON, OC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3150 0104), OFFICE OF HAHAGENENT AND BUDGET WASHINGTON DC 20503.

FACILITY HAHE (1) DOCKET NINBER (2) LER NIIIBER (6) PAGE (3)

S E DUE N T I AL REVISION R.E. Ginna Nuclear Power Plant 05000244 NUHBER HUNGER 6 OF 10

-- 007-- 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

G. SAFETY SYSTEM RESPONSES:

All safeguards equipment functioned properly. The "B" Emergency D/G automatically started due to the undervoltage condition on buses 16 and 17, displayed proper voltage and frequency, and reenergized safeguards buses 16 and 17 to supply emergency power.

Running containment recirculation fans on bus 16 tripped as designed and were manually restarted as needed to restore normal cooling to the Containment. The running service water, pump on bus 17 tripped as designed and the pump selected for autostart started when power was restored to bus 17.

III. CAUSE OF EVENT A., 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 the loss of power from Circuit 751.

C. ROOT CAUSE:

The underlying cause of the loss of power from Circuit 751 was electrical storm activity that affected circuits at offsite Station 204 and tripped the "C" phase instantaneous overcurrent protective relay for Circuit 751 (at Station 204), deenergizing Circuit 751.

This event is NUREG-1022 Cause Code (C), "External Cause". This loss of power and subsequent start of an Emergency D/G does not meet the NUMARC 93-01, "Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants", definition of a "Maintenance Preventable Functional Failure".

HRC FORH 366A (5-92)

NRC FORM 366A U.S. NUCLEAR REGULATORY C(HHISSIOM APPROVED BY OHB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPOHSE TO COMPLY NITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORIIARD COMMENTS REGARDIHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS NAMAGEMENT BRANCH TEXT CONTINUATION (HNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION/

IIASHIMGTOH, DC 20555-0001 AND TO THE PAPERNORK REDUCTION PROJECT (3150.0104), OFFICE OF MANAGEMENT AND BUDGET MASHINGTOM DC 20503.

FACILITY NAME (1) DOCKET MINBER (2) LER MINBER (6 PAGE (3)

SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 NUMBER NUMBER 7OF10 95 -- 007-- 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

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.

An assessment was performed considering both the safety consequences and implications of this event with the following results and conclusions:

There were no operational or safety consequences or implications attributed to the loss of Circuit 751 and start of the Emergency D/G because:

All reactor control and protection systems performed as designed.

Although the maintenance work for the "B" Emergency D/G had been completed, the "B" Emergency D/G remained administratively inoperable. It was available for operation and subsequently functioned as designed to reenergize "B" train safeguards buses 16 and 17.

Whi'le in this condition, the plant electrical power system (offsite power sources and the Emergency D/Gs) remained within the requirements of the Limiting Condition for Operation (LCO) of Technical Specification (TS) 3.7.2.2.b.l, which requires that the "A" Emergency D/G be demonstrated operable within'ne hour of the "B" Emergency D/G being inoperable and at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> thereafter. The "A" Emergency D/G had been demonstrated operable within one hour of 0422 EDST on August 3, so no further actions were required by TS for the short time that, Circuit 751 was also inoperable on August 3; Circuit 767 remained in operation supplying power to the "A" train safeguards buses; subsequently, Circuit 767 was lined up to supply power to the "B" train safeguards buses also, as permitted by TS.

HRC FORM 366A (5-92)

NRC FORM 366A U.S. NUCLEAR REGULATORY CQNI SSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY MITH THIS INFORHATION COLLECTIOH REQUEST: 50.0 HRS.

FORNARD COHHEHTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE IHFORHATION AND RECORDS MANAGEHENT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION/

MASHINGTOH, DC 20555-0001 AND TO THE PAPERNORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET MASHINGTON DC 20503 FACILITY NAHE (1) DOCKET NQlBER (2) LER NIIIBER (6) PAGE (3)

SEQUENTIAL REVISIOH YEAR R.E. Ginna Nuclear Power Plant NUHBER NUHBER 05000244 007 00 8 OF 10 TEXT (If more space is required, use additional copies of HRC Form 366A) (17) o Radiation monitor channels R-10A, R-11, and R-12 were temporarily lost. The common sample pump was manually restarted within a few minutes, which is within the required action time of TS 3.1.5.1.2 to obtain a grab sample at least once every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Based on. the above, safety was 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 Offsite power was restored to safeguards buses 16 and 17 from Circuit 767, and the "B" Emergency D/G was stopped and realigned for auto standby, prior to the start of post-maintenance testing of the "B" Emergency D/G.

o Circuit 751 was cleared for use by Energy Operations, protective relays for Circuit 751 (at Station 204) were reset by Energy Operations, and Circuit 751 was reenergized and restored to operable status.

B. ACTION TAKEN OR PINNED TO PREVENT RECURRENCE:

As stated in LER 95-006, options for offsite power configuration to the plant will be reevaluated to optimize reliability during adverse weather conditions. (Refer to LER 95-006, Revision 0, Docket No. 50-244.) The primary option currently being evaluated would use a n100% / 0%" offsite power configuration as the preferred configuration, with Circuit 767 normally supplying power to both the "A" and "B" train safeguards buses.

NRC FORM 366A (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 llITH THIS INFORHATIOH COLLECTIOH REGUEST: 50.0 COMMENTS REGARDING BURDEN ESTIMATE TO MRS'ORHARD LICENSEE EVENT REPORT (LER) THE INFORMATION AHD REQ)RDS MANAGEMENT BRANCH TEXT CONTINUATION (MHBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, lIASHIHGTON, DC 20555-0001 AND TO THE PAPERlSRK REDUCTION PROJECT (3180-0104), OFFICE OF MANAGEMENT AND BUDGET MASHINGTON DC 20503.

FACILITY NAME (1) DOCKET HWBER (2) LER MQIBER (6) PAGE (3)

SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant NUMBER HUMBER 9OF10 05000244 95 007-- 00 TEXT (If more space is required, use additional copies of HRC 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: LERs91-002, 92-007,94-012, and 95-006 were similar events with similar root causes (start of an Emergency D/G due to loss of offsite power from external causes).

C. SPECIAL COMMENTS:

None HRC'ORM 366A (5-92)

~ MRC FORM 366A U.S. MUCI.EAR REGULATORY COWISSIOM APPROVED BY QGI HO. 3150-0104 EXPIRES 5/31/95 (5.92)

ESTIMATED BURDEN PER RESPOHSE TO COMPLY MITH THIS INFORMATION COLLECTIOH REQUESTS 50.0 FORMARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) TNE INFORMATION AllO RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (liHBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, llASNIHGTOH, DC 20555-0001 AMD TO THE PAPERUORK REDUCTION PROJECT (3150.0104) I OFF ICE OF NAMAGENEHT AMD BUDGET MASHINGTON DC 20503.

FACILITY NAME (1) DOCKET NQIBER (2) LER NLNBER (6) PAGE (3)

SEQUENTIAL REVISION YEAR R.E. Ginna Nuclear Power Plant 05000244 NUMBER NUMBER g5 -- 007-- 00 10 OF 10 TEXT (If more space is required, use additionaL copies of NRC Form 366A) (17)

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