Information Notice 1985-32, Recent Engine Failures of Emergency Diesel Generators

Recent Engine Failures of Emergency Diesel Generators

ML031180336
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	04/22/1985
From:	Jordan E NRC/IE
To:
References
IN-85-032, NUDOCS 8504190055
Download: ML031180336 (5)

SSINS No.: 6835 IN 85-32 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 April 22, 1985 IE INFORMATION NOTICE NO. 85--32: RECENT ENGINE FAILURES OF EMERGENCY DIESEL

GENERATORS

Addressees

All nuclear power reactor facilities holding an operating license (OL) or a

construction permit (CP).

Purpose

This information notice is provided to alert recipients of potentially signifi- cant problems pertaining to engine failures of emergency diesel generators. It

is expected that recipients will review the information for applicability to

their facilities and consider actions, if appropriate, to preclude a similar

problem occurring at their facilities. However, suggestions contained in this

notice do not constitute NRC requirements; therefore, no specific action or

written response is required.

Description of Circumstances

During the last few months, engine failures of emergency diesel generators have

occurred at three reactor sites. These events are significant because more

than one diesel generator had been affected at two of the sites and because of

the extent of damage caused by the failures.

On January 10, 1985, the Detroit Edison Company notified the NRC of a trip on

low lube oil pressure of the number 11 emergency diesel generator engine at the

Enrico Fermi Atomic Power Plant Unit 2 (Fermi). Subsequent inspection revealed

damage to connecting rod bearings and main bearings bn the upper crankshaft as

well as to some pistons. The upper crankshaft was scored. The upper crank- shaft; upper main and connecting rod bearings; upper pistons numbers 2, 3, and

4; and cylinder liners numbers 2, 3, and 4 were replaced.

The other three diesel generator engines at Fermi were inspected. On the

number 12 engine, some of the upper bearings had been damaged; all upper

bearings were replaced. The number 13 and number 14 engines showed preliminary

signs of wear, but no repairs were necessary.

At North Anna Power Station Unit 2, both diesel generators experienced engine

failures over the last several months. On December 9, 1984, both diesel

generators were inoperable at the same time. Inspection of the 2J diesel

generator engine revealed that upper pistons, numbers 2 and 3, were leaking

8504190055

IN 85-32 April 22, 1985 and the number 11 cylinder liner seal was leaking. The upper pistons, numbers

2, 3, and 11, and cylinder liner number 11 were replaced. The 2H diesel

generator engine was found to have shattered rings on the number 10 lower

piston. The number 10 lower piston and rings were replaced.

On February 2, and again on February 4, 1985, the jacket water tank for one of

the diesel generator engines at North Anna Power Station Unit 1 was found to be

empty. On the second occasion, water leakage in the engine was observed.

Subsequent inspection revealed jacket water in other cylinders and in the

engine lube oil, severe scoring of the number 3 cylinder liner and upper

piston, seizure of the number 3 upper piston, and three failed upper main

bearings. The apparent cause of trouble on the engine was the failure of a

jacket water seal, which resulted in loss of lubrication to the number 3 cylinder and engine lube oil dilution of which, in turn, caused bearing damage.

There appears to be a similarity between this failure and the Unit 2 engine

failures in December 1984 as well as the Unit 2 engine failure in June 1983.

On March 15, 1985, the 2J engine at North Anna Power Station Unit 2 tripped on

high crankcase pressure. Subsequent inspection revealed that two cylinder

liners were leaking coolant; they were replaced. Several upper piston insert

assemblies also required replacement parts. The lower pistons of the cylinders

with damaged parts were inspected, but no abnormal wear was found.

In February 1985, a diesel generator engine at William B. McGuire Nuclea'

Station Unit 2 tripped on low lube oil pressure. During subsequent testing, excessive engine vibration prompted plant operators to manually trip the

diesel. Brass metal was found on the oil screens. Four of eleven main bear- ings were damaged; all main and connection rod bearings were replaced as a

precaution. One piston and the crankshaft also are being replaced because of

scoring. Following inspection of the other diesel engine, the licensee re- placed all main bearings as a precaution because scoring and close tolerances

were noted.

Discussion:

Detroit Edison Company has attributed the Fermi engine failure to inadequate

lubrication during fast starts. The engines at Fermi are Fairbanks-Morse Model

Number 38D8 1/8 of the opposed-piston design. Each engine has a keep-warm

system, a manually controlled prelube system, and a lube oil booster for the

upper crankshaft. The booster is filled with two gallons of oil that is forced

by starting air pressure into the upper crankline bearings. The booster was

installed in 1982 for the number 11 and number 12 engines and in 1983 for the

other two. Detroit Edison Company discontinued manual prelubrication in

January 1984. Engine number 11 has experienced approximately 100 starts

without manual prelubrication.

IN 85-32 April 22, 1985 In consultation with the engine manufacturer, Detroit Edison Company has made, or plans, the following changes as a result of this problem:

1. Revise surveillance test procedures and Technical Specifications to

a. prelube all planned starts

b. start engine at idle speed, run for five minutes, and then increase

to synchronous speed

c. increase load in incremental steps

d. on shutdown, decrease load in incremental steps

2. Inspect and replace oil filters and inspect strainers on a quarterly

basis.

3. Conduct bearing inspections (after 20 unplanned starts or after 18 months, whichever comes first) to detect any future problems.

4. Analyze oil samples, including an analysis for metallics on a monthly

basis for the next 18 months for trend determination.

5. Perform a spectrographic analysis of lube oil filter media and any depos- its that are found during the quarterly replacement.

The engines at North Anna Units 1 and 2 were also manufactured by

Fairbanks-Morse. The cause of the water leaks have not been determined.

The engines at McGuire Unit 2 were manufactured by Nordberg. It appears that

misalignment of the lower crankcase bed contributed to the damage at McGuire.

In this case, it is of interest that oil samples taken some months ago had some

metal products in them, which at the time were considered to be the result of

normal bearing wear-in. Oil samples taken recently had higher levels of

contaminants.

The above identified engine problems occurred in engines that were far from the

end of their normal design lives. While the exact causes of these premature

failures have not been determined, there is reason to believe that the testing

requirements may have aggravated existing situations. Good operating practic- es, coupled with careful maintenance and periodic inspections, therefore are

important. In addition, it is apparent that minimizing stress and wear on the

diesel generator engines by testing, in accordance with the manufacturer's

recommendations, also is essential. As part of Generic Letter 84-15, "Proposed

Staff Actions to Improve and Maintain Diesel Generator Reliability," the staff

proposed measures to reduce the severity of engine starts and loadings. In

responding to the generic letter, many licensees apparently did not elect to

consider changes to fast start and fast loading test requirements.

IN 85-32 April 22, 1985 In light of the above problems, licensees may want to reconsider the desir- ability of-reducing the severity of engine starts and loading by proposing

changes to the Technical Specifications to accomplish the goals of Generic

Letter 84-15. Furthermore, facility owners may desire to reevaluate the

adequacy of their maintenance, testing, and operating practices for the re- quired engine service and to take steps to monitor wear on key engine parts

such as bearings.

No specification response is required by this information notice. If you have

any questions about this matter, please contact the Regional Administrator of

the appropriate NRC regional office or this office.

• Ddwarirector

Divisi of Emergency Preparedness

and E'fgineering Response

Office of Inspection and Enforcement

Technical Contacts: E. M. McKenna, NRR

(301) 492-7468 R. J. Kiessel, IE

(301) 492-8119 Attachment: List of Recently Issued IE Information Notices

• '

.. r

Attachment 1 IN 85-32 April 22, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-31 Buildup Of Enriched Uranium 4/22/85 All uranium fuel

In Ventilation Ducts And fabrication licensees

Associated Effluent Treatment

Systems

85-30 Microbiologically Induced 4/19/85 All power reactor

Corrosion Of Containemnt facilities holding

Service Water System an OL or CP

85-29 Use Of Unqualified Sources 4/12/85 All well logging

In Well Logging Applications source licensees

85-03 Separation Of Primary Reactor 4/9/85 All power reactor

Sup. 1 Coolant Pump Shaft And facilities holding

Impeller an OL or CP

85-28 Partial Loss Of AC Power And 4/9/85 All power reactor

Diesel Generator Degradation facilities holding

an OL or CP

85-27 Notifications To The NRC 4/3/85 All power reactor

Operations Center And facilities holding

Reporting Events In Licensee an OL or CP

Event Reports

85-26 Vacuum Relief System For 4/2/85 All BWR facilities

Boiling Water Reactor Mark having a Mark I or

I And Mark II Containments Mark II containment

and holding an OL or

CP

85-25 Consideration Of Thermal 4/2/85 All power reactor

Conditions In The Design And facilities holding

Installation Of Supports For an OL or CP

Diesel Generator Exhaust

Silencers

85-24 Failures Of Protective 3/26/85 All power reactor

Coatings In Pipes And Heat facilities holding

Exchangers - an OL or CP

OL = Operating License

CP = Construction Permit