ML19351F892

Interim Deficiency Rept SD 413-414/81-01 Re Insufficient Lubrication of Turbocharger Thrust Bearings Supplied by Elliot Co,Initially Reported on 810105.Design Mod for Piping Oil to Bearings Is Being Tested.Final Rept by 820101

ML19351F892
Person / Time
Site:	Catawba
Issue date:	01/28/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, SD-413-414-81-0, NUDOCS 8102200442
Download: ML19351F892 (3)

Text

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January 23, 1981

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3. c. =.:: .c < :- r>cn M.r. J. P. O'Reilly, Director U. S. Nuclear Regulatcry Commission Region !I 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 Re: Cataw'ca Nuclear Station ilnits 1 and 2 Decket Nos. 50-4 3 and 50-414

Dear Mr. O'Reilly:

Pursuant to 10CFR 50.55e, please find attached Significant Deficiency Report SD-413-414. 31- 01.

Very truly yours, j -

f.

William O. Parker, Jr.

RWO:scs Attachment cc. /Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555

$O/ 7 s

l I 8102200442 .

,s DUKE POWER COMPANY CATAWBA NUCLEAR STATION j

4 Report Number: SD 413-414/81-01 Report Date: January 21, 1981

eacility

Catawba Nuclear' Station, Unit l's 2 Identification of Deficiencv:

Sue to the lack of oil (no pre-lubing) during the standby mode, the turbo-charger thrust bearings may experience rapid and/or premature wear.

Initial Report:

On January 5, 1981, Mr. John Rausch of NRC Region II, Atlanta,-Georgia was notified of this deficiency by Mr. J. R. Wells, and Mr. W. J. Foley of Duke Power Company, Charlotte, N. C. 2S242. This notification was in response to John Wilder's (Transamerica Delaval) letter dated December 22, 1980, to Mill Power Supply Company.

Supplier and/or Component:

Elliott Company of Jeannette, Pennsylvania =anufactured the turbochargers that Transamerica Delaval installed on the Catawba diesels for Units 1 and 2. The diesels are designated 1A, 1B, 2A, and 2B.

Description of Deficier:v:

The potential defect exists in the lubricating oil system that supplies oil to the turbocharger bearings. The design of this system permits lubricating i

' oil to flow to the bearings only when the diesel is running, and due to a check valve, prevents oil flow to the bearings when the diesel is in the stand-i by mode. When-the turbocharger is at rest,-(standby mode) the turbocharger l bearing lube oil system is bypassed to prevent the possibility of oil leaks at

the turbocharger bearing seals.

If oil under pressure was available at the tu-bocharger. bearings seals, while the diesel is in the standby mode, and directly after running, there is a possibility the seals would allow oil to leak onto the hot turbocharger -

fapellers and cause a fire.

Since the diesels are routinely started once a month, and run for a short length of time, an additional potential . problem of premature bearing wear i

'must be considered. The bearing lube oil system, and the rocker box share a common oil line. The bearings are located approximately three (3) feet-above the-rocker box. Because of this arrangement, the oil in'the line to the bearings drains to the levels of. the oil in -the rocker box. Therefore, when the diesels are started, there is an insufficient amount of oil on the i bearings to prevent the bearings f rom smearing and causing e::cessive and premature bearing wear.

, The wear rate for this condition, after 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> of operation, was determined

] by Transamerica Delaval to be equivalent to 15000-20000 hours of continuous  ;

operation. This data was based on an investigation of the turbocharger bear-1 ings used at the Southern California Edison, San Onofre Plant.

Analysis of Safety Implication: -

, I t

If the deficiency was not corrected, thete would be excessive bearing wear and would eventually result in turbocharger impeller wobble. If corrective action were not taken, the possibility of further bearing and/or turbocharger' damage could result.

i

, Due to the necessity of a bearing replacement in this situation, and assuming 4

it could occur in each unit diesel generator-simultaneously,-both diesel

, generators could be unavailable. .This could result in the unavailability of on site power.

Corrective Action:

l 1 Transamerica Delaval has designed the system modification that corrects the generic deficiency described above. The modification involves piping a small' amount of oil to the bearings and causing the oil to drip on the bearings through an orifice (.014" diameter) at a given rate. This modification is

expected to greatly extend the bearing wear rate and is not a potential fire j hazard.

This modification is presently being tested on another similar Transamerica. ,

Delaval diesel turbocharger. The results of the = edification will be' forwarded

to Duke Power for evaluation and implementation as soon as possible. In addi- i l tion, Transamerica Delaval will supply drawings, parts list, and detailed

, instructions necessary to modify the turbocharger lube oil system by March 9, l 1981.

l An installation schedule based on the above data will be implemented and a. final response will be submitted prior to .Jacuary 1,1982.

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