ML20082D489

Forwards Annual DG Reliability Data Rept for 1994

ML20082D489
Person / Time
Site:	Farley
Issue date:	04/03/1995
From:	Dennis Morey SOUTHERN NUCLEAR OPERATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9504100135
Download: ML20082D489 (12)

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~ Southern Nuclear Operating Company

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? Birmingham, Alabama 352011 l*<

' Telephone (205) 868-5131 Southern Nudear Operating Company o... ue,.y Vee President

. Farley Project the southem electnc system April 3.-1995 10 CFR 50.36 -

Docket Nos.'. 50-348 50-364

' U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Joseph M. Farley Nuclear Plant Annual Diesel Generator Reliability Data Reoort For 1994 Ladies and Gentlemen:

Provided as Attachment 1 is the Annual Diesel Generator (D/G) Reliability Data Report for I1994, which is sub nitted in accordance with Farley Nuclear Plant (FNP) Technical Specification 6.9.1.12. This report provides the number of tests (valid or invalid) and the number of failures for the D/Gs at FNP for 1994. Attachment 2 provides the information -

j identified in Regulatory Position C.3.b of Regulatory Guide 1.108, Revision 1, August 1977, for the failures. Please note that D/G 2C data is not listed in the 1994 report since it falls under the Station Blackout AAC Reliability Program.

FNP recently performed a review of D/G test data which revealed errors made during -

l previous interpretations of D/G data. As a result of this review, FNP is submitting a l

corrected 1993 Diesel Generator Reliability Data Report. The corrected report is included as Attachment 3. In addition, FNP is taking corrective actions to preclude future errors in D/G test reporting.

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j Ui S. Nuclear Regulatory Commission Page 2 If there are any questions, please advise.

Respectfully Submitted, SO'UTHERN NUCLEAR OPERATING COMPANY p %ul EFil'maf 94dgannt. doc Attachments cc:

Mr. B. L. Siegel Mr. S. D, Ebneter Mr. T. M. Ross

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ATTAC11 MENT 1 ANNUAL DIESEL GENERATOR RELIABILITY DATA REPORT FOR 1994 4

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ANNUAL DIESEL GENERATOR RELIABILITY DATA REPORT FOR 1994 4 Diesel"GensretorW 1:112 0 slB1 >

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Valid Successful Starts 19 15 24 17 75 Invalid Tests 17 9

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ATTACHMENT 2

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' INFORMATION IDENTIFIED IN REGULATORY POSITION C.3.B OF -

REGULATORY GUIDE 1.108, REVISION 1, AUGUST 1977

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n INFORMATION IDENTIFIED IN REGULATORY POSITION C.3.B OF REGULATORY GUIDE 1.108, REVISION 1, AUGUST 1977 The following paragraphs provide the information required by the Regulatory Position C.3.b of Regulatory Guide 1.108, Revision 1,1977, for the valid failures during 1994.

2B D/G Failure on 04-11-94 At 0036 on 04-11-94, while performing normal surveillance on the 2B D/G, it was noted that the speed and frequency began to oscillate and that speed control was not responding normally.

Investigation determined that the D/G showed signs ofintermittent fuel starvation because of: Fuel Pressure Low alann; fuel pressure indication fluctuation; and engine surging. Maintenance thoroughly inspected the day tank, day tank foot valve, suction header, priming pump, engine driven fuel pump &

pump drive assembly and fuel filters. They also conducted a pressure test of the suction header. The Maintenance Engineering Group reviewed previous maintenance history and found that no maintenance had been performed since the last successful surveillance test. They also reviewed 2B diesel nm logs and did not identify any suspect trends. In addition, they consulted with Coltec Industries regarding the occurrence.

As a result of the inspection and pressure test, the following actions were taken: although found to be clean, the fuel filters were replaced; a very small leak on the engine-driven pump suction line found during the pressure test was repaired; and an internal relief for the engine driven fuel pump was found to have worn components and was replaced.

Upon completion of the repairs, the diesel successfully completed a return-to-service surveillance and was restored to operable status. The 2B D/G was unavailable for 75.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. This failure was the third failure in the last 100 valid tests and the first failure in the last 20 valid tests.

Afler this failure, the surveillance schedule remained at once per 31 days, which is in conformance with the Joseph M. Farley Technical Specifications, Table 4.8-1, " Diesel Generator Test Schedule". Note that this Table deviates from the test schedule contained in Regulatory Position C.2.d in Regulatory Guide 1.108, Revision 1, August 1977.

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IC D/G Failure on 10-21-94 At 1209 on 10-21-94, while performing FNP-0-STP-80.2, " Diesel Generator 1C Operability Test", a small fire was observed by the exhaust manifold. The fire was extinguished with a dry chemical fire extinguisher. Immediately following the fire, the diesel automatically tripped on high crankcase pressure.

Disassembly and inspection of the crankcase ejector system determined that maintenance practices used allowed foreign material, in the form of carbon, to enter the supply hose of the eductor for crankcase vacuum. The carbon blocked the throat of the venturi of the eductor allowing a positive pressure in the crankcase. An inspection of the air supply and vacuum piping to the ejector revealed no abnormalities.

The source of oil that had dripped onto the exhaust manifold and ignited was traced to the generator load cutout switch push rod. The seal for this push rod is designed to protect against vacuum loss and when the diesel generator obtained a positive crankcase pressure, some oil escaped and dripped onto the exhaust manifold. The Coltec Factory Representative inspected the seal and determined that it was in satisfactory condition. The area of the diesel generator where the fire had been, [ exhaust manifold], was also examined by ts Coltec Representative, who determined that no damage could be detected. There was no evidence of the small amount of the dry chemical that had been used to extinguish the fire. No indications were present that indicated a fire in the crankcase.

Procedure FNP-0-MP-13.1, Rev.17, Emergency Diesel Generators 1C and 2C Refueling Il year - 18 mitnth] Inspection, has been revised regarding the removal, cleaning and inspection of the crankcase vacuum ejector assembly. This change will minimize the possibility of carbon particles getting into the air supply to the crankcase vacuum ejector assembly. A step was also added for the verification of the existence and size of an orifice in the air supply to the crankcase vacuum ejector assembly. In addition, a note was incorporated to verify crankcase vacuum. This note provides instructions to observe this parameter under full load conditions and to notify the D/G Engineer ifit is outside of the target band [2 in. w. c. to 3 in. w. c. vacuum).

Upon completion of the repairs, the diesel successfully completed a return-to-service surveillance and was restored to operable status at 1604 on 10-22-94. Due to this failure, the IC D/G was unavailable for 27.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />. This failure was the first failure in the last 100 valid tests and the first failure in the last 20 valid tests.

After this failure, the surveillance schedule remained at once per 31 days, which is in conformance with the Joseph M. Farley Technical Specifications, Table 4.8-1, " Diesel Generator Test Schedule" Note that this Table deviates from the test schedule contained in Regulatory Position C.2.d in Regulatory Guide 1.108, Revision 1, August 1977.

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ATTACIIMENT 3 1993 CORRECTED DIESEL GENERATOR RELIABILITY DATA REPORT 8

1993 CORRECTED DIESEL GENERATOR RELIABILITY DATA REPORT Provided as Attachment 1 is the Annual Diesel Generator (D/G) Reliability Data Repon for 1993, which is submitted in accordance with Farley Nuclear Plant (FNP) Technical Specification 6.9.1.12. This report provides the number of tests (valid or invalid) and the number of failures for each D/G at FNP for 1993. Attachment 2 provides the information identified in Regulatory Position C.3.b of Regulatory j

Guide 1.108, Revision 1, August 1977, for the failure.

Please note that there were two Technical Spe:ification revisions during 1993 that affected D/G testing i

and tracking of failures. The first revision was Technical Specification Amendments 98 (Unit 1) and 90

,j (Unit 2), effective June 20,1993, which changed the tracking methodology regarding the number of D/G runs and failures. Prior to June 20,1993, the D/G runs and failures were tracked by D/G type l

(2850 kW or 4075 kW). Per the above amendments, D/G runs and failures are tracked per each D/G q

(1-2A,1B,2B,1C,2C). This revision also modified Technical Specification Table 4.8-1, " Diesel Generator Test Schedule," which specifies the testing frequency based on the number of D/G failures.

The second revision affecting this report was Technical Specification Amendments 101 (Unit 1) and 93 l

(Unit 2), effective October H21,1993, which defined the 2C D/G as the Alternate AC (AAC) source l

instead of an emergency D/G. The 2C D/G will be tested and maintained per the Station Blackout AAC Reliability Program. Due to this Technical Specification revision,2C D/G runs and failures after October H21,1993, are not included in this report.

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ANNUAL DIESEL GENERATOR RELIABILITY DATA REPORT FOR 1993

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v Valid Successful 27 26 25 22 25 24 28 27 22 21 427 120 l

Tests Invalid Tests 17 15 17 17 18 20 19 87 88 l

Valid Failures 0

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2C D/G Failure on 2-8-93 Ihgfallowing paragraphs _ provide _the information re.q. uirred_by_R_egulatory Position C.3.b of Regulalar.y Guide _.Llo8.. Revision L.1221 for the.yalid.failurgs..during_1.221 At 0370 on 2-8-93. while ogrforming normal surveillance on the 2C D/G. it was noted that the voltage regulator was not r.c3 pan _ ding to optr._atpLippy.t Invcitigation determined.thatthg3ntomatic voltage _ggntmLLA.XC)lglay wasfound_to have an open spil. In addition. the_undervoltage (Tvne SV-1) relay was found to have damaged contacts.

Thuelays.wcre insp;sted and/pt hench.. tested,.Jn.ndditian,.the..auta.yaltageJwilgh relay (AYS), whigh is_a lime dglay relayaasRstedand.found.10 he ppgrrating.p.er dgsignJLwas_dstcrmined thatths.failurs nLthe AVC relay coil was_due to excessive coil currents resulting from contact arcing in the undcIyphagelclay, ThgAXC.telay wasigplaggd with.gnew relay...the undervoltaguglay_qsntacts in sgrvice werucphiced svilhJparg. contacts on the existing relay and the diesel was tested satisfactorily. The 2C D/G was unayfailable for 16.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> _T_hisfailprg_was the second failure in the last 100 valid tests.

A8ct.1hitfailurg.thuurygillancuchsdnlelsmained al.onge.pgr 14 days which was in confprmance lyith_Amsndments_26 (Unit _l) and 13 (Unit 2) of the Joseph M. Farley Technical Specifications. Table 18-1 "Diesgl_Dgnerator Test Schedule" and Regulatory Positjan C.2.d in Regulatory Guide 1.108.

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2C D/G Failure an 10-113-93 l

Ihg_[pilmying pr3graphiprovide the information requir_ed by Reculatory Position C.3.b of Regulatory Qui le 1.108. Revision 1.1977 for the valid _ failures during 1993.

l At 0403 on 10-11-93, while performing normal surveillance on the 2C D/G, it was noted that the voltage regulator was not responding to operator input.

Investigation determined that the automatic voltage control (AVC) relay was found to have an open coil. In addition, the undervoltage (Type SV-1) relay was found to have pitted contacts and the main plunger was intermittently sticking or binding.

The relays were thoroughly inspected and/or bench tested. It was determined that the failure of the AVC relay coil was due to excessive coil currents caused by poor contact mating and resultant contact arcing in the undervoltage relay. The poor contact mating, arcing, and pitting of the undervoltage relay were a result of damage to the relay plunger, shaft, and core assembly due to wear.

The AVC and undervoltage relays were replaced and the diesel was tested satisfactorily. Ip_ prevent fuuhcr_pioblems. a preventative maintenange_1.alk was established to inspect _and test the undervoltage a

relays on a regulaLbatit_The 2C D/G was unavailable for 23.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. This failure was the second-third failure in the last 100 valid tests, and the firstseppnd failure in the last 20 valid tests.

MAfter this failure the surveillance schedule-remained-at+nce-per-31-< lays would ha.yg changed to qnge pet 1 slay 3, which is in confonnance with the Joseph M. Farley Technical Specifications, Table 4.8-1,

" Diesel Generator Test Schedule". Table 4.8-1 deviates from the test schedule contained in Regulaton/

Position C.2.d in Regulatory Guide 1.108, Revision 1, August 1977; however, as noted on the cover page, this table was modified per Technical Specification Amendments 98 (Unit 1) and 90 (Unit 2).

lifTcpliveAfter October 19M,1993, the 2C D/G test schedule was performed in accordance with the Station Blackout AAC Reliability Program.

MDuc lo_TechnicalSpecifcation Arnendments 101 (UniL1) and 91_1UniL2)Jhis change in the i

stydllancc_1c3tingint_en al was nqLrequired.

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