ML17300B015
| ML17300B015 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/24/1987 |
| From: | Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 161-00461-JGH-R, 161-461-JGH-R, TAC-64398, NUDOCS 8708260344 | |
| Download: ML17300B015 (8) | |
Text
REGULA INFORMATION DISTRIBUTIO YSTEM (RIDS)
ACCESSION NBR: 8708260344 DOC. DATE'7/08/24 NOTARIZED:
NO DOCKET 0 FACIL:STN-50-530 Palo Verde Nuclear Stationi Unit 3i Arizona Pub li 05000530 AUTH. NAKE AUTHOR AFFlLIATION HAYNES'. G.
- r izona Nuclear Power Prospect (formerly Arizona Public Serv RECIP. NAME RECIP lENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards documentation re 861223 failure of Emergency Diesel Generator B> subsequent engine trips due to testing of Main Bearing 2 5 testing after bearing insp 8c reassembly after third high bearing temp trip. Problems discussed e/NRC.
DISTRIBUTION CODE:
A001D COPIES RECEIVED: LTR /
ENCL Q SIZE:
TITLE:
OR Submittal:
General Distribution NOTES: Standardized plant. M. Davisi NRR: iCg.
05000530 REC lP IENT ID CODE/NAME PD5 LA LICITR*iE INTERNAL'CRS NRR/DEST/ADS NRR/DEST/MTB NRR/DOE*/TSB OGC/HDS1 RES/DE/EIB EXTERNAL:
EG8cG BRUSKEi S NRC PDR NOTES:
COPIES LTTR ENCL 1
0 1
1 6
6 1
1 1
1 0
1 1
1 1
1 1
1 1
REC IP IENT ID CODE/NAME PD5 PD DAVIS' ARM/DAF/LFMB NRR/DEBT/CEB NRR/DEST/RSB NRR/
ILRB ILE 01 LPDR NSIC COPIES LTTR ENCL 5
5 1
1 1
0 1
1 1
1 1
1 1
1 1
1 1
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 29 ENCL 26
(h
2 Arizona Nuclear Power Project P.O. BOX 52034
~
PHOENIX, ARIZONA85072-2034 August 24, 1987 161-00461-JGH/RAB U. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C.
20555
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 3 Docket No.
STN 50-530 (License No. NPF-65)
Additional Information on the Unit 3 Diesel Generator Testing File:
87-G-056-026
Reference:
Letter from E.
E.
Van Brunt, Jr.
(ANPP) to USNRC dated June 28, 1987.
Subject:
Status of Diesel Generator Testing.
Dear Sir:
The referenced letter discusses the December 23, 1986 failure of the Unit 3 B
emergency diesel generator, the subsequent engine trips experienced due to the 82 main bearing during
- testing, and the testing to be done after the inspection and reassembly of the 82 main bearing after the third high bearing temperature trip.
On July 9,
- 1987, the testing program to determine the acceptability of the engine repairs was completed.
The NRC required inspections of the 89 crankpin, the 89 connecting rod bearing, and the 82 main journal and bearing were completed by Mr.
Tomlinson of the NRC staff and representatives from
- Services, and the bearing manufacturer, Clevite.
The inspection indicated that the engine would perform its function.
During the exit interview with Mr. Tomlinson, he requested that a written summary of the other problems which had occurred during the engine test program be provided to the Commission.
The problems had all been previously discussed with the NRC staff, but had not been documented.
The attachment to this letter provides the requested information.
If you have any additional questions on this
- matter, please contact Mr. W. F. Quinn or Mr. R. A. Bernier of my staff.
Very truly yours, 870826O~"
50O05gO 70824 PDR IIIIDOCK 0 pDR p
JGH/RAB/dim J.
G.
Haynes Vice President Nuclear Production cc:
0.
M. De Michele G.
W. Knighton M. J. Davis J.
B. Martin J. Ball A. C. Gehr
o a
I,'Ij C
ATTACHMENT The first of the events, for which information was requested, occurred on June 5,
1987 during the engine start subsequent to the first run after engine repairs had been completed.
The initial run after repairs was a
15 minute unloaded run.
After the initial run the engine remained shutdown for approximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
On the next start the engine tripped on an incomplete starting sequence when the engine would not turnover.
Investigation determined that there was water in the 88R cylinder.
The head on 88 right was removed and inspected.
A crack was located on the head between the two exhaust valves.
The cylinder liner was cracked vertically about 20 inches long on the inside (exhaust side).
Results from an independent Lab has revealed-that the crack originated at the water jacket side of the head.
The outer surfaces of the head received a
NDE inspection after the 89 rod failure; this examination would not have detected any failures at that time.
It is suspected that the crack propagated to the surface of the head during the initial 15 minute run.,
During the time the engine was shut
- down, the jacket water leaked in to the 88 right cylinder.
When the next start was initiated, the 88 right piston was coming up on the compression stroke and'herefore ruptured the liner.
The liner,
- head, and piston were
- replaced, and subsequent engine operation indicate satisfactory results.
On June 28,
- 1987, the engine tripped because of an indicated turbocharger thrust bearing failure.
Investigation revealed that the eutectic trip device had not been properly adjusted during reinstallation after the December engine failure.
The thrust bearing clearance was checked and found to be the same as recorded during the inspection of the turbo charger after the rod failure of December 23, 1986.
The trip device was properly reinstalled and has operated satisfactorily.
The last of these events occurred on June 30, 1987 when the engine tripped due to crankcase overpressure.
Investigations revealed the following at the 89L cyclinder:
1)
Heavy scuffing.was readily visible on the liner of about 10 inches around the circumference and 12 inches high.,
2)
The, piston showed signs of distress equal to the liner,, and the area of heaviest contact was "heat-cheeked",
however,,all rings were free to,move in their grooves and had suffered no damage beyond that which arose
- from, the expansion of the piston.
3)
When the piston and its articulated rod were removed from the liner, it was not possible to move the piston pin in its bushing.
Seizure of the piston pin was such that the piston was cut apart in order to remove the pin and bushing together, then the bushing was cut to remove the pin for evaluation.
~ P P
4)
The piston pin had'n area of approximately 3 inches around the pin by 4 inches long that exhibited very heavy contact with the bushing.
5)
A review of the reassembly records revealed the clearance between the pin and bushing of.005 inches
(.005 to.006 inches required)'.
6)
The records also showed no reference to a "blueing" check for the 89L piston pin to bushing.to ensure a minimum of 80X contact area.
The crankcase overpressure occurred when vapors in the crankcase flashed',
due to friction induced heat generated by contact of the piston and cylinder liner.
It has been determined that an inadequate contact area was the cause of,the piston pin seizure'he
.piston pin has been sent to an independent lab for
- analysis, but at this time, their report has.not been finalized.
The test program was restarted after the reassembly of the 9L cylinder and was completed
,on July 9,
1987 as stated above.
ANPP, in conjunction with the engine manufacturer,,
has concluded that all of the problems encountered during the Restart Testing Program have been totally independent of each other and have been corrected.
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