Information Notice 1989-07, Failures of Small-Diameter Tubing in Control Air, Fuel Oil & Lube Oil Systems Render Emergency Diesel Generators Inoperable

Failures of Small-Diameter Tubing in Control Air, Fuel Oil & Lube Oil Systems Render Emergency Diesel Generators Inoperable

ML031180501
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, 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
Issue date:	01/25/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-007, NUDOCS 8901180357
Download: ML031180501 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 25, 1989 NRC INFORMATION NOTICE NO. 89-07: FAILURES OF SMALL-DIAMETER TUBING IN

CONTROL AIR, FUEL OIL, AND LUBE OIL

SYSTEMS WHICH RENDER EMERGENCY DIESEL

GENERATORS INOPERABLE

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is being provided to alert addressees to events in- volving breaks or cracking of small-diameter tubing which can render emergency

diesel generators (EDGs) inoperable. Failures apparently caused by vibration

have occurred in the tubing of the instrumentation and control air system as

well as in the fuel oil and lube oil systems of EDGs. These events have sig- nificant safety implications because of the loss of, or the potential loss of, ability of safety-related equipment to perform its intended safety function.

It is expected that recipients will review the information for applicability

to their facilities and consider actions, as appropriate, to avoid similar

problems. However, suggestions contained in this information notice do not

constitute NRC requirements; therefore, no specific action or written response

is required.

Description of Circumstances

Cooper Nuclear Station

During an operability surveillance test of an emergency diesel generator on

October 21, 1988, at Cooper Station (Nebraska Public Power District), a loss

of control air pressure occurred and the 'Turbo Bearing Wear' annunciator

alarmed. The control air system is a subsystem of the starting air system.

The starting air goes through two pressure-reducing valves, set at 80 psi and

30 psi, respectively, to supply 30 psi control air. The control air subsystem

maintains the engine at a set speed regardless of engine load and protects the

engine from abnormal conditions through protective trip functions. During

engine operation the control air supplies 80 psi air to hold the fuel racks in

position. If control air is shut off or-if any of the diesel generator trips

occur, the 80 psi air flow to the fuel shutoff cylinder is stopped, dumping the

fuel racks and tripping the EDG.

8901180357 ZAr

- -IN 89-07 January 25, 1989 After the overspeed shutdown relay and the valve associated with maintaining

a constant air pressure for the various EDG protective trip mechanisms

rebuilt, the control air pressure still could not be sustained. were

Subsequently, the licensee identified a circumferential crack in a i-inch stainless

instrument line during a walkdown inspection of the control air system.steel

cracked line allowed the 30 psi control air to bleed off, reducing pressure The

the safety trip valve solenoid which shut down the EDG. Approximately on

of the line was removed and replaced with a compression fitting. The 1 inch

restarted, and the test was successfully completed. EDG was

Nebraska Public Power District forwarded the cracked piece of stainless

tubing to a testing laboratory for analysis to determine the cause of steel

failure. At this time, engine vibration is assumed to be the cause the

failure. The licensee has introduced design changes to relocate all of the

engine- mounted instruments subject to high vibration from the engine onto instrument

racks. The modifications are scheduled for the next refueling outage.

Similar events in the instrumentation and control air system previously

curred at Cooper Station in both 1975 and 1981. These problems were oc- thought

to have been resolved by replacement of the original copper tubing

less steel tubing. The EDGs at Cooper Station were manufactured by with stain- Energy Systems of Cooper Industries (so-called Cooper-Bessemer EDGs).Cooper

Wolf Creek Generating Station

A break in the fuel oil line of an EDG at Wolf Creek Generating Station

resulted in a fire on November 27, 1988. A fuel oil leak emanated from

a compression fitting on a 1-inch surge tank line. The leak quickly

creased from a drip to a spray over approximately 45 minutes. Since in- leak appeared to be between the nut and the ferrule and was believed the

to

be correctable with the unit in service, and because the EDG was undergoing

a 24-hour endurance test, operations personnel did not shut down the

EDG.

When the attending personnel discovered that the leak had increased signifi- cantly, they notified the shift supervisor, and, consequently, the EDG

secured by a control room operator. As the load was reduced, the attending was

personnel noted flames, reported the fire to control room and security

nel, and actuated the fire alarm. Within about 3 minutes from the time person- attending personnel first noticed the fire, the fire was out. the

Severe fretting on a horizontal section of the damaged i-inch fuel line

was

observed when the section was removed for repair. The fretting apparently

was caused by vibration-induced rubbing against the larger line to which

fuel line was attached. The broken line also appeared to have been the

broken and repaired in the same place. At that time, the fuel line previously

had been

shortened, which could have introduced additional stresses at the location

the new break. A post-event walkdown inspection of the EDG revealed of

further

evidence of inadequate support and fretting of other small fluid lines.

Previously, on December 4, 1986, a similar event occurred at Wolf Creek

involved the same fuel line on one of the other EDGs, also during a 24-hour that

IN 89-07

__ January 25, 1989 endurance test. In this instance, the leak through the wall of the i-inch

fuel line was caused by fretting similar to that observed on the fuel line

that failed in the event previously described. In addition, a number of other

problems have occurred involving small-diameter fluid lines on the EDGs as a

result of vibration. In January 1985, two fuel oil leaks resulted from holes

rubbed in a section of J-inch steel tubing. In February 1985, sections of both

the control air system and the fuel oil lines failed to meet minimum wall thick- ness requirements because of wear from vibration. In December 1987, a cracked

lube oil line fitting caused the EDG to shut down after 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of a 24-hour

endurance test. The Wolf Creek EDGs were manufactured by Colt-Pielstick/Colt

Industries.

Discussion:

These events indicate that small-diameter tubing installed on EDGs is suscepti- ble to vibration-induced failures which could render the EDGs inoperable. The

vibration-induced failures may appear as cracking or breaks as well as holes

and wall thinning caused by rubbing of components that contact. These failures

are not limited Just to specific manufacturers, systems, or materials. The

common underlying cause of the failures is the inadequate design or installa- tion of the supports for the small-diameter tubing in a vibration environment.

As the potential unavailability of an EDG has such a significant impact on

reactor safety, addressees may wish to review the small-diameter tubing of

the Instrumentation and control air system as well as the tubing of the fuel

oil and lube oil systems of their EDGs. It is important to determine whether

vibration can introduce cracks or breaks and whether these failures could lead

to inoperability of the EDGs.

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: G. L. Constable, RIV

(817) 860-8151 J. P. Jankovich, NRR

(301) 492-1167 W. C. Seidle, RIV

(817) 860-8148 Attachment: List of Recently Issued NRC Information Notices

IN 89-07 January 25, 1989 endurance test. In this instance, the leak through the wall of the i-inch

fuel line was caused by fretting similar to that observed on the fuel line

that failed in the event previously described. In addition, a number of other

problems have occurred involving small-diameter fluid lines on the EDGs as a

result of vibration. In January 1985, two fuel oil leaks resulted from holes

rubbed in a section of i-inch steel tubing. In February 1985, sections of both

the control air system and the fuel oil lines failed to meet minimum wall thick- ness requirements because of wear from vibration. In December 1987, a cracked

lube oil line fitting caused the EDG to shut down after 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of a 24-hour

endurance test. The Wolf Creek EDGs were manufactured by Colt-Pielstick/Colt

Industries.

Discussion:

These events indicate that small-diameter tubing installed on EDGs is suscepti- ble to vibration-induced failures which could render the EDGs inoperable. The

vibration-induced failures may appear as cracking or breaks as well as holes

and wall thinning caused by rubbing of components that contact. These failures

are not limited just to specific manufacturers, systems, or materials. The

common underlying cause of the failures is the inadequate design or installa- tion of the supports for the small-diameter tubing in a vibration environment.

As the potential unavailability of an EDG has such a significant impact on

reactor safety, addressees may wish to review the small-diameter tubing of

the instrumentation and control air system as well as the tubing of the fuel -

oil and lube oil systems of their EDGs. It is important to determine whether

vibration can introduce cracks or breaks and whether these failures could lead, to inoperability of the EDGs.

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

If you have any questions about this matter,.,please contact one of the..techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: G. L. Constable, RIV

(817) 860-8151 J. P. Jankovich, NRR

(301) 492-1167 W. C. Seidle, RIV

(817) 860-8148 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES D

01// ^89

• OGCB:DOEA:NRR *RIV *RIV *RPB:ARM *C/OGCB:DOEA:NRR

JJJankovich GLConstable WSeidle TechEd CHBerlinger

12/29/88 12/29/88 01/09/89 01/12/89 01/05/89

IN 89-XX

January xx, 1989 endurance test. In that instance, the leak through the wall of the 1i-nch fuel

line was caused by fretting similar to that observed on the fuel line which

failed in the event described above. In addition, a number of other problems

have occurred involving small diameter fluid lines on the EDGs as a result of

vibration. In January 1985 two fuel oil leaks resulted from holes rubbed in a

section of i-inch steel tubing. In February 1985, sections of both the control

air system and the fuel oil lines failed to meet minimum wall thickness require- ments because of wear due to vibration. In December 1987 a cracked lube oil

line fitting caused the EDG to shut down after 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> into a 24-hour endurance

test. The Wolf Creek EDGs were manufactured by Colt-Pielstick/Colt Industries.

Discussion:

These events indicate that small diameter tubing installed on EDGs is suscepti- ble to vibration induced failures which could render the EDGs inoperable. The

vibration induced failures may appear as cracking or breaks as well as holes

and wall thinning due to rubbing of components which contact each other. These

failures are not limited just to specific manufacturers, systems, or materials.

The common underlying cause of the failures is the inadequate design or instal- lation of the supports for the small diameter tubing in a vibration environment.

Since the potential for unavailability of an EDG has such a significant impact

on reactor safety, all licensees are encouraged to review th small diameter

tubing of the instrumentation and control air system as well as the tubing of

the fuel oil and lube oil systems of their EDGs. The licensees are encouraged

to determine whether vibration can introduce cracks or breaks and whether these

failures could lead to inoperability of the EDGs, and to consider actions, as

appropriate, to avoid similar problems.

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: G. L. Constable, RIV

(817) 860-8151 J. P. Jankovich, NRR

(301) 492-1167 W. C. Seidle, RIV

(817) 860-8148 Attachment: List of Recently Issued NRC Information Notices

• Transmitted by dated

D/DOEA:NRR

CERossi

01/ /89

• OGCB:DOEA:NRR RIV RIV4g r P&M C/OGCB:DOEA:NRR

JJJankovich GLConstable WSeifte TechEd CHBerlinger

12/29/88 12/ /88 12/, /88 12-/--te&- 01/ /89 be¢~qjb z /Y7

IN 89-XX

January xx, 1989 endurance test. In that instance, the leak through the wall of the i-inch fuel

line was caused by fretting similar to that observed on the fuel line which

failed in the event described above. In addition, a number of other problems

have occurred involving small diameter fluid lines on the EDGs as a result of

vibration. In January 1985 two fuel oil leaks resulted from holes rubbed in a

i-inch steel tubing. In February 1985 both the control air system and the fuel

oil lines failed to meet minimum wall thickness requirements because of wear

due to vibration. In December 1987 a cracked lube oil line fitting caused the

EDG to shut down after 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> into a 24-hour endurance test. The Wolf Creek

EDGs were manufactured by Colt-Pielstick/Colt Industries.

Discussion:

These events indicate that small diameter tubing installed on EDGs is suscepti- ble to vibration induced failures which could render the EDGs inoperable. The

vibration induced failures may appear as cracking or breaks as well as holes

and wall thinning due to rubbing of components which contact each other. These

failures are widespread and are not limited just to certain manufacturers, to

specific systems, or to certain materials. The common underlying cause of the

failures is the inadequate design or installation of the supports for the small

diameter tubing in a vibration environment.

Since the potential for unavailability of an EDG has such a significant impact

on reactor safety, all licensees are encouraged to review the small diameter

tubing of the instrumentation and control air system as well as the tubing of

the fuel oil and lube oil systems of their EDGs. The licensees are encouraged

to determine whether vibration can introduce cracks or breaks and whether these

failures could lead to inoperability of the EDGs, and to consider actions, as

appropriate, to avoid similar problems.

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: G. L. Constable, RIV

(817) 860-8151 J. P. Jankovich, NRR

(301) 492-1167 W. C. Seidle, RIV

(817) 860-8148 Attachment: List of Recently Issued NRC Information Notices

• Transmitted by dated D________

D/DOEA:NRR

CERossiAi g

pg 0/ /g~

• OGCB:DOEA:NRR RIV r RIV6 RPB: ARM C/OGCB: RD

JJJankovich GLContle WSe e TechE Lv CHBerlinger

12/29/88 Adfi - /;z rv Hi/// i 01/ -/89 Lvt

IN 88-XX

December xx, 1988 endurance test. In that instance, the leak through the wall of the 1-inch fuel

line, was also caused by fretting similar to that observed on the fuel line

which failed in the event described above. In addition a number of other

problems have occurred involving small diameter fluid lines on the EDGs as a

result of vibration. In January 1985 two fuel oil leaks resulted from holes

rubbed in a i-inch steel tubing. In February 1985 both the control air system

and the fuel oil lines failed to meet minimum wall thickness requirements

because of wear due to vibration. In December 1987 a cracked lube oil line

fitting caused the EDG to shut down after 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> into a 24-hour endurance

test. The Wolf Creek EDGs were manufactured by Colt-Pielstick/Colt Industries.

Discussion:

These events indicate that small diameter tubing installed on EDGs is suscepti- ble to vibration induced failures which could render the EDGs inoperable. The

vibration induced failures may appear as cracking or breaks as well as holes

and wall thinning due to rubbing of components which contact each other. These

failures are widespread and are not limited Just to certain manufacturers, to

specific systems, or to certain materials. The common underlying cause of the

failures is the inadequate design or installation-of the supports for the small

diameter tubing in a vibration environment.

Since the potential of unavailability of an EDG has such a significant impact

on reactor safety, all licensees are encouraged to review the small diameter

tubing of the instrumentation and control air system as well as. the tubing.of

the fuel oil and lube oil systems of their EDGs. The licensees are encouraged

to determine whether vibration can introduce cracks or breaks and whether these

failures could lead to inoperability of the EDGs, and to consider actions, as

appropriate, to avoid similar problems.

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional, Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: G. L. Constable, RIV

(817) 860-8151 J. P. Jankovich, NRR

(301) 492-1167 W. C. Seidle, RIV

(817) 860-8148 Attachment: List of Recently Issued NRC Information Notices

• Transmitted by dated

D/DOEA:NRR

CERossi

12/ /88 OGCB:DOEA:NRR RIV RIV RPB:ARM C/OGCB:DOEA:NRR

JJJankoviathl GLConstable WSeidle TechEd CHBerlinger

12/60/88Td 12/ /88 12/ /88 12/ /88 12/ /88