ML20081C157

Diesel Generator Status Rept

ML20081C157
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	10/20/1983
From:	LONG ISLAND LIGHTING CO.
To:
Shared Package
ML20081C142	List: ML20081C140 ML20081C157
References
NUDOCS 8310310133
Download: ML20081C157 (7)

Text

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October 20, 1983 b

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DIESEL GENERATOR STATUS REPgRT0CT 27 P3 :43

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I. Diesel Generator 101 at f ,;u: ;i The disassembly of diesel generator 101 following comple- i tion of the torsional stress tests has now been completed. I l

g Inspections conducted during and following the disassembly dis- '

b g cicsed pitting on the lobes of the camshaft. S:=:lar p:: ting r.

E was not observed on the camshafts of the other two enginen.

FaAA is investigating this condition. New lobes will be installed.

Also, pitting was observed on the no. 1 cylinder liner. This pitting is the same as that observed and previously reported with respect to two other cylinder liners, one on each engine.

This problem has been corrected by replacing the cylinder liner with a spare.

The lube oil flush of the diesel generator 101 auxiliary systems remaining in the diesel generator room is currently in

{:: progress.

During removal of the rotor from the stator on the

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c generator for diesel generator 101, a bolt in the rigging spreader bar broke, causing the rotor to drop 7/16" onto its cradle. Subsequent inspections of the rotor and the stator, including an inspection by the manufacturer, disclosed no damage.

Also, subsequent megger checks of the rotor and stator were completed with satisfactory results.

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Diesel Generator 102 j II.

l The reassembly of diesel generator 102 has been completed and the engine has been reinstalled in the diesel generator room. Final alignment of the engine is now in progress.

The lube oil flushes for portions of the system left in the diesel generator room 102 have been completed. Substantial pertions of the jacket water system flushes have also been completed.

3 Investigation of the cause or causes of indicat.ent on p

the diesel generator 102 baseplate is continuing and the resultn will be reported in FaAA's forthcoming interim report. At this time, it appears that certain damage to.the baseplate was caused by the crankshaft failure.

As previously reported, the governor for diesel generator 102 has been sent to the governor manufacturer for inspection.

Preliminary information from that inspection indicates that the governor was damaged as a result of the failure of the crank-shaft on diesel generator 102. A report from the manufacturer is expected to be available in approximately two weeks. Inspec-tions of the governors on diesel generators 101 and 103 did not

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g reveal any damage.

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As noted in previous status reports, electrical testing of the 102 generator rotor disclosed a low megger reading at the no. 7 pole. The rotor was returned to the manufacturer, Parsons Peebles-Electric Products, Inc., for analysis. The results of the analysis are currently being reviewed by Transamerica Delaval 3 3 2 1_CMlizi&9isfE M 4W80# N E M A*lN D'O N U~E E E# - # ^

t (TDI) and will be available in approximately one week. Pre-1 liminary information indicates that the coil of rotor pole no. 7 ,

grounded as a result of mechanical damage to the insulation on ,

the pole. The mechanical damage was caused by a sharp corner located close to the winding. This corner was rounded off and the rotor pole was repaired. Also, the rotor balance and shaft y runout were checked and found to be satisfactory. The rotor Y

y has been returned to Shoreham for reinstallation.

W The jacket water pump for diesel generator 102 was in-spected and indications of shaft wear were found. The pump impeller is press fitted to the shaft and also held in place with an appropriate lock nut and washer. The shaft wear ob-served indicated there may have been some slippage of the impeller on the shaft. The entire jacket water pump for diesel generator 102 will be sent to Palo Alto for evaluation by FaAA. The jacket water pumps on diesel generators 101 and 103 have also been in-spected and no similar conditions were found.

I f Inspection of the diesel generator front end gear train E

disclosed fretting of the jacket water pump drive gear. This condition has been observed on all three engines to varying degrees and is presently under investigation by FaAA. Results of this investigation will be included in an FaAA report. New drive gears have been or will be installed on all three diesel generators.

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As reported in previous status reports, an investigation of the conditions observed with respect to the connecting rod bearings is in progress. Suffolk County was previously provided with a copy of the attached preliminary report by FaAA concerning the bearings. New connecting rod and main bearings will be in-stalled in all three diesel generators. Destructive testing 6 and nondestructive examination of a representative sa ple of f

1[ both types of bearings will be perfermed to previde assurance f that the connecting rod and main bearings meet the appropriate material specifications. The bearing matter was reported to the NRC under 10 CFR E 50.55(e). Further information concerning the connecting rod bearings will be included in a subsequent FaAA report.

III. Diesel Generator 103 The reassembly of diesel generator 103 has been completed and the engine has been moved to its diesel generator room.

( Final positioning of the engine has been completed and the engine 2

i g flywheel installed.

% The installation of the generator is cur-h4 rently in progress.

F Diesel generator 103 has been released for f;

e reconnection of piping to the diesel engine and this work is in I progress.

The lube oil flush and substantial portions of the jacket water system flushes have been completed for diesel generator 103.

The generator for diesel generator 103 has been inspected by representatives of the manufacturer both visually and using

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l electrical megger checks.

These inspections yielded satisfactory results.

IV. New Crankshafts The new crankshaft for diesel generator 101 is expected to arrive at Shoreham on October 21, 1983.

ri V. Schedule p The FaAA interi.. report s e t t i r. ; f e r t t. TAAA's t o e.c . w e s o m e N

concerning the cause or causes of the diesel generator 102 crankshaft failure is now scheduled to be completed on or about November 3, 1983. At present, it is LILCO's intention to schedule a publicly noticed meeting on or about November 3 with the NRC Staff and Suffolk County to distribute and explain FaAA's interim report on the cause or causes of the crankshaft failure.

In previous status reports, reference has been made to a

{ comprehensive FaAA report to follow the November 3 interim L

( report.

In order to provide the Board and the parties with L

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information more expeditiously and to avoid delay in any litiga-lJ tion relating to the diesels, FaAA will follow the interim g

report with additional ' reports on specific subjects as 'the in- I formation is obtained and the conclusions reached. For example, it is anticipated that on or about November 3, 1983, FaAA will also issue a report on the adequacy of the structural integrity )

of the 13" x 12" crankshaft. Other aspects of FaAA's investiga-tion will be addressed in subsequent reports to be issued as promptly as practicable.

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FC 9C1 pe7tlL PAD N.TO. CAKCRMaA MSc3 fat 518564400 PEMORMOUM TO: Mike Milligan FROM: Lee Swanger L DATE: October 13, 1933

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RE: Sumary of Findings: Eruergency Diesel Engine Connecting Rod Bearings Four upper connecting rod bearings from the TDI Enterprise Diesel Engines were, upon disassembly, found to have cracks through the alumi-num bearing alloy. One of the bearinDs was completely fractured into two pieces. Total time on these bearings was between 600 and 820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br />.

Certain observations, calculations, and tests were performed to deter-mine the cause of bearing cracking. These are discussed individually below.

j 1. Mechanical procerties below speci fica tion. Tests by the bearing

' r.anuf acturer. TUI, revealed that the ul timate tensile strength and the tensile elongation wre below the specifications published by p Alcoa, the source of the castings, at the time of saanufacture.

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r UTS t- Elongation p Specification 27,000 psi minimum 27. minimum P

Test Results 15,000 psi minimum 0% minimum This discrepancy in mechanical properties is believed to be a significant contribu' tor to the early fracture of these bearings.

2. Unsupported bearing ends, Large (%") chamfers on the original connecting rods used witn the 11" journal crankshaf t left over 2/g" of each end of the bearing back unsupported by the steel connecting rod. This resulted in a cantilever effect which probably contri-i buted to the observed made of cracking.

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3. Edge loading of the bearing.

The contact patterns ib the babbitt lined bearing inner ~ diameters show that the load on these bearings was concentrated at the ends of the bearings. This edge loading r,ay have been due to journal " tilting" or " yawing" due to the raxiaum dynamic torque transmitted through the journals.

partially supported bearing backs (point 2), Cc.bined with the contributed to the observed code of bearing cracking.this ef fect probably 4.

Excessive bearing Peak r.anuf Oil Film Pressure (PDFP). A major independent engine acturer

$ was engagea to compute k flim properties in the connecting rod bearings.the hydrodynaste The pest oil file oil 4 pressure was calculated to be 29,745 psi. For s tat t o. a ry diesci s in ,

% intermittn t service, tAis bearing raa nu re c turer ( I r.p e c i a l Cl e e t te

, Inc.) would reco:r3end PCFP no higher than 26,000 pst for the solid aluminum bearing saterial used in these connecting rods.

The high value of PDFP, combined wi th the geometric condi tions addressed in points 2 and 3 probably contributed to the observed bearing fractures.

Changes in Bearing Configuration Associated with Change of Crankshafts Replacement of the crankshafts by new ones with 12" diameter journals has rods.resulted in the installation of different bearings and connecting The effects of the changes are discussed individually below.

1. Material properties meet specifications. TDI has reported to FaAA that they have increased tneir QA activities in the area of bearing i materials since the manufacture of the fractured rod bearings. Cur-A rent procedures should increase the probability that the material in k the replacement bearing meets specifications,

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2. Supported bearing ends.

The new connecting rod bores have scall,

' As , cha=fers and tnerefore completely support the bearing backs, h' 3. Reduced edge loading.

The new 12" Journal diameter crankshafts will develop lower peak torques and rtsist Jcurnal "til ting" and thus decrease the degree of edge loading on the bearings, t 4 Reduced Peak Oil _ Film Pressure, in a The larger diameter journal results lower calculated PDFP at full load of 26,780 psi. Combined wfth improved geometry, this bearing life of 8,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />. level of PDFP predicts an expected signtficant influence on fatigue life of the bearings. Reducing engine out 80%

15,000 output hours.(2,800 KW) would almost double expected bearing life toRunning at LA5:bl/M&T2-7396 cc: R. McCarthy J. Thomas G. Rogers

' C. Wells I

. Tim Ellis (Hunton & William)