Information Notice 1986-73, Recent Emergency Diesel Generator Problems

Recent Emergency Diesel Generator Problems

ML031250129
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, 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, 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, 05003543, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	08/20/1986
From:	Jordan E NRC/IE
To:
References
IN-86-073, NUDOCS 8608180089
Download: ML031250129 (3)

SSINS No.:

6835 IN 86-73

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

August 20, 1986

IE INFORMATION NOTICE NO. 86-73:

Addressees

All nuclear power reactor facilities holding an operating license or a

construction permit.

Purpose

This notice is to alert addressees to vibration-induced fuel line wear and of

a deficiency in the design of the field flash circuitry on nuclear plant emer- gency diesel generators. Recipients are expected to review the information for

applicability to their facilities and consider actions, if appropriate, to pre- clude similar problems occurring at their facilities. However, suggestions

contained in this information notice do not constitute NRC requirements; there- fore, no specific action or written response is required.

Description of Circumstances

Nine Mile Point Unit 2

While conducting diesel generator testing in early May 1986, it was discovered

that diesel fuel lines had experienced extensive wear and fuel leaks in the

area of the clamps that mount the fuel lines to the diesel engine.

The diesels

are Cooper-Bessemer model KSV-16-T, 600 rpm, 4 stroke, 16 cylinder units with

low total operating hours.

Fuel line damage was caused by vibration from the diesel engine and fuel system

pulsation induced by rapid, repeated cycling of a fuel system relief valve.

This valve relieves from the low pressure fuel system via a cooler to the fuel

day tank to control low pressure fuel system pressure.

The manufacturer proposes

to correct the problem by inserting plastic sleeves between the fuel line and

its hold down clamps and installing a dashpot on the relief valve to dampen its

operation.

Watts Bar Units 1 and 2

In April 1986 a deficiency was identified which affects all five standby diesel

generators (DGs) at Watts Bar Nuclear Plant and could prevent the OGs from

developing a voltage output when required in an emergency.

The affected DGs are

tandem 16-645 E4 units supplied by Morrison-Knudson Co.

The normal shutdown

cycle of the DG includes a 10-minute cooldown run at about 450 rpm.

If during

8608180089

IN 86-73 August 20, 1986 this idle period an emergency start signal were received, the DG would accelerate

to the normal 900 rpm operating speed, but the generator field would not be

flashed and an output voltage therefore would not be developed.

This problem has also been determined to exist on the HPCS DG at Grand Gulf

Nuclear Station.

This unit was supplied by General Motors Corporation.

The root cause of this deficiency has been found to be a design error by the

manufacturer.

During a normal or emergency start, as the OG accelerates past

475 rpm, logic is completed to flash the generator field.

When output voltage

has built up, the field flash circuitry is automatically disabled.

The logic

design is such that engine speed must go below 200 rpm to re-enable the field

flash circuitry, thus no field flash will occur if an emergency start signal

is received during the 450 rpm cooldown period.

Field flash would be needed

under these circumstances because the self-excitation path is interrupted early

in the shutdown sequence.

The corrective action proposed by the OG manufacturer is to modify the control

circuitry to eliminate the speed dependence of field flash reset.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

l

Administrator of the appropriate regional office or this office.

,r . Jordan, Director

Divisi /of Emergency Preparedness

and

l ineering Response

Kevin Wolley, IE

(301) 492-8373 Attachment:

List of Recently Issued IE Information Notices

'IL

Attachment 1

IN 86-73

August 20, 1986

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

86-72

86-71 Failure 17-7 PH Stainless

Steel Springs In Valcor

Valves Due to Hydrogen

Embrittlement

Recent Identified Problems

With Limitorque Motor

Operators

8/19/86

8/19/86

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

86-70

Spurious System Isolation

Caused By The Panalarm Model

86 Thermocouple Monitor

8/18/86 All GE BWR

holding an

facilities

OL or CP

86-69

86-68

86-67

86-66

86-65

86-64 Scram Solenoid Pilot Valve

8/18/86 (SSPV) Rebuild Kit Problems

Stuck Control Rod

8/15/86 Portable Moisture/Density

8/15/86 Gauges: Recent Incidents And

Common Violations Of Require- ments For Use, Transportation, And Storage

Potential For Failure Of

8/15/86

Replacement AC Coils Supplied

By The Westinghouse Electric

Corporation For Use In Class

lE Motor Starters And

Contractors

Malfunctions Of ITT Barton

8/14/86

Model 580 Series Switches

During Requalification Testing

Deficiencies In Upgrade

8/14/86

Programs For Plant Emergency

Operating Procedures

All BWR facilities

holding an OL or CP

All BWR

holding

facilities

an OL or CP

All NRC licensees

authorized to possess, use, transport, and

store sealed sources

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

OL = Operating License

CP = Construction Permit