Information Notice 1993-48, Failure of Turbine-Driven Main Feedwater Pump to Trip Because of Contaminated Oil

Failure of Turbine-Driven Main Feedwater Pump to Trip Because of Contaminated Oil

ML031070473
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, 05000036, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	07/06/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-048, NUDOCS 9306290301
Download: ML031070473 (13)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 July 6, 1993 NRC INFORMATION NOTICE 93-48: FAILURE OF TURBINE-DRIVEN MAIN FEEDWATER PUMP

TO TRIP BECAUSE OF CONTAMINATED OIL

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information

notice to alert addressees to potential problems resulting from suspended

particles in the control oil in the trip system for turbine-driven main

feedwater pumps. 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 are not NRC requirements; therefore, no specific action or written

response is required.

Description of Circumstances

On August 27, 1992, while at 80-percent power, LaSalle County Station, Unit 2, experienced a reactor scram when the main turbine tripped. Several unexpected

control system responses occurred. The focus of this information notice is on

the failure of both turbine-driven main feedwater pumps to trip on both -

automatic and manual signals. This failure resulted in uncontrollable filling

of the reactor vessel above the coolant level setpoint (Level 8) for trips of

the motor-driven main feedwater pump, the reactor core isolation cooling

system, and the high-pressure core spray system. When the reactor coolant

level reached the administrative limit for coolant level (above Level 8),

operators manually closed the outboard main steam isolation valves to prevent

the downstream main steamlines from being filled with water. This action also

terminated steam flow to the turbine-driven main feedwater pump. Closure of

the turbine stop valves by local mechanical trip actions for both turbine- driven main feedwater pumps was successful only after repeated attempts.

Discussion

At LaSalle, a control oil system is used to trip closed the turbine stop valve

to shut down the turbine for each of the two turbine-driven main feedwater

pumps. Control oil, as well as bearing lubrication oil, for both pumps is

supplied from the main turbine lubrication oil system reservoir. The main

turbine lubrication oil system does not contain an oil filter in the

9306290301 PAR Itio\-T3C c 3- cOC-

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IN 93-48 July 6, 1993 control oil line to the turbine-driven feedwater pump stop valves.

The

licensee determined that the root cause of the failure of the turbine-driven

main feedwater pumps to trip was suspended particles in the main

turbine oil

system. Suspended particles in the oil created flow blockages

in

oil dump valves. This prevented proper drainage of the trip system. the control

the accumulated particles were small, but some were up to 6 mm Most 'of

(1/4 in.) long.

The licensee believes this condition resulted from an accumulation

the low flow areas of the control oil ports over a period of time. of crud in

maintenance program had not included flushing of these ports in The

previous

refueling outages. Operators flushed the control oil system, replaced

parts, and tested the system before returning it to service. The several

licensee

plans to include flushing these ports in preventive maintenance

mechanisms. of these trip

In Generic Letter 89-19, "Request for Action Related to Resolution

Unresolved Safety Issue A-47, 'Safety Implication of Control Systemsof

Nuclear Power Plants' Pursuant to 10 CFR 50.54(f)," the NRC identifiedin LWR

number of safety concerns resulting from coolant overfill events. a

water reactors, reactor vessel overfill events can affect the safety 'In.boiling

plant in several ways. In pressurized water reactors, steam generatorof the

overfill events produce similar concerns. The safety concerns

arise from

potential increased loads on steamline supports from increased deadweight

seismic forces, potential water hammer loads, potential release or

excessive cooling caused by stuck-open secondary safety valves, of coolant or

potential

inoperability of important valves in the secondary system, and potential

weakening-of steam-generator tubestromtr-ternally induced tbens~ldoads

(mainly applicable to once-through steam generator designs).

This information notice requires no specific action or written response.

you have any questions about the information in this notice, please If

one of the technical contacts listed below or the appropriate Office'ofcontact

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: T. Greene, NRR

(301) 504-1175 V. Hodge, NRR

(301) 504-1861 Attachment:

List of Recently Issued NRC Information Notices

/I

tKIVH Atta-bment

IN 93-48 July 6, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

92-06, Reliability of ATWS 07/01/93 All holders of OLs or CPs

Supp. 1 Mitigation Systems and for nuclear power reactors.

Other NRC-Required Equip- ment not Controlled by

Plant Technical Specifica- tion

93-47 Unrecognized Loss of 06/18/93 All holders of OLs or CPs

Control Room Annunciators for nuclear power reactors.

93-46 Potential Problem with 6/10/93 All holders of OLs or CPs

Westinghouse Rod Control for Westinghouse (W)-

System and Inadvertent designed nuclear power

Withdrawal of A Single reactors.

Rod Control Cluster Assembly

93-45 Degradation of Shutdown - 06/16/93 :All holders of OLs or CPs

Cooling System Performance for nuclear power reactors.

93-44 Operational Challenges 06/15/93 All holders of OLs or CPs

During A Dual-Unit for nuclear power reactors.

Transient

93-43 Use of Inappropriate 06/10/93 All holders of OLs or CPs

Lubrication Oils in for nuclear power reactors.

Safety-Related Applications

93-42 Failure of Anti-Rotation 06/09/93 All holders of OLs or CPs

Keys in Motor-Operated for nuclear power reactors.

Valves Manufactured by

Velan

93-41 One Hour Fire Endurance 05/28/93 All holders of OLs or CPs

Test Results for Thermal for nuclear power reactors.

Ceramics Kaowool, 3M

Company FS-195 and

3M Company Interam E-50

Barrier Systems

OL = Operating License

CP = Construction Permit

IN 93-48 V.2July 6, 1993 control oil line to the turbine-driven feedwater pump stop valves. The

licensee determined that the root cause of the failure of the turbine-driven

main feedwater pumps to trip was suspended particles in the main turbine oil

system. Suspended particles in the oil created flow blockages in the control

oil dump valves. This prevented proper drainage of the trip system. Most of

the accumulated particles were small, but some were up to 6 mm (1/4 in.) long.

The licensee believes this condition resulted from an accumulation of crud in

the low flow areas of the control oil ports over a period of time. The

maintenance program had not included flushing of these ports in previous

refueling outages. Operators flushed the control oil system, replaced several

parts, and tested the system before returning it to service. The licensee

plans to include flushing these ports in preventive maintenance of these trip

mechanisms.

In Generic Letter 89-19, "Request for Action Related to Resolution of

Unresolved Safety Issue A-47, 'Safety Implication of Control Systems in LWR

Nuclear Power Plants' Pursuant to 10 CFR 50.54(f)," the NRC identified a

number of safety concerns resulting from coolant overfill events. In boiling

water reactors, reactor vessel overfill events can affect the safety of the

plant in several ways. In pressurized water reactors, steam generator

overfill events produce similar concerns. The safety concerns arise from

potential increased loads on steamline supports from increased deadweight or

seismic forces, potential water hammer loads, potential release of coolant or

excessive cooling caused by stuck-open secondary safety valves, potential

inoperability of important valves in the secondary system, and potential

weakening of steam generator tubes from thermally induced tensile loads

(mainly applicable to once-through steam generator designs).

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: T. Greene, NRR

(301) 504-1175 V. Hodge, NRR

(301) 504-1861 Attachment:

List of Recently Issued NRC Information Notices

• See previous concurrences

• OEAB:DORS *SC/OEAB:DORS *Tech Ed *C/HICB:DRCH

TGreene RDennig DGable JWermiel

12/18/92 01/08/93 12/16/92 02/02/93 3r

C/EMEB:DEit *C/OEAB:DORS *OGCB:DORS *C/OGCB:DORS

JNorberg AChaffee VHodge GMarcus

C /(p/93 03/29/93 06/16/93 05/17/93 D/93

[OFFICIAL RECORD COPY]

DOCUMENT NAME: 93-48.IN

IN 93-XX

June xx, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: T. Greene, NRR

(301) 504-1175 V. Hodge, NRR

(301) 504-1861 Attachment:

List of Recently Issued NRC Information Notices

• See previous concurrences

• OEAB:DORS *SC/OEAB: DORS *Tech Ed *C/HICB:DRCH

TGreene RDennig DGable JWermiel

12/18/92 01/08/93 12/16/92 02/02/93

• C/OEAB:DORS *OGCB: DORS *C/OGCB: DORS D/DORS

AChaffee VHodge GMarcus BGrimes

$ /1,193 03/29/93 06/16/93 05/17/93

",vke4S

[OFFICIAL RECORD COPY]

DOCUMENT NAME: S:\DORSSEC\LSIN

IN 93-XX

June xx, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: T. Greene, NRR

(301) 504-1175 V. Hodge, NRR

(301) 504-1861 Attachment:

List of Recently Issued NRC Information Notices

• See previous concurrences

• OEAB:DORS *SC/OEAB: DORS *Tech Ed *C/HICB:DRCH

TGreene RDennig DGable JWermi el

/ / 01/08/93 12/16/92 02/02/93 C/EMEB:DE *C/OEAB: DORS OGCB:DORSJ *C/OGCB:DORS D/DORS

JNorberg AChaffee VHodge GMarcus BGrimes

/ /93 03/29/93 06/%W/93 05/17/93 / /

[OFFICIAL RECORD COPY]

DOCUMENT NAME: S:\DORS SEC\LSIN

IN 93-XX

May xx, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: T. Greene, NRR

(301) 504-1175 Attachment: List of Recently Issued NRC Information Notices

• See previous concurrences

• OEAB:DORS *SC/OEAB:DORS *Tech Ed *C/HIC BDRCH

TGreene RDennig DGable JWermiel

12/18/9/ 01/08/93 12/16/92 02/02/93 D/DORS C/EMEB: DE

• C/OEAB:DORS j C/OGCB:DORS

JANorberg

AChaffee " -

GMarcus aft( BGrimes

03/29/93 o5lo S/f7/1 3 I / M#> / /93

[OFFICIAL RECORD COPY]

DOCUMENT NAME: LSIN

IN 93-XX

May xx, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: T. Greene, NRR

(301) 504-1175 Attachment: List of Recently Issued NRC Information Notices

• See previous concurrences

• OEAB:DORS *SC/OEAB:DORS *RPB:ADM *C/HICB:DRCH

TGreene RDennig Tech Ed VI C JWermiel

12/18/93 01/08/93 12/16/92 If' 02/02/93

• C/OEAB:DORS C/OGCB:DORS D/DORS

AChaffee GMarcus BGrimes

03/29/93 / / / /

[OFFICIAL RECORD COPY]

DOCUMENT NAME: LSIN

IN 93-XX

March xx, 1993 governor standard ports over a period of time. The feedwater oil systems, including these ports, will be flushed during refueling outages to prevent the

accumulation of particulates in low flow areas of the system.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: T. Greene, NRR

(301) 504-1175 Attachment: List of Recently Issued NRC Information Notices

• See previous concurrences

OEAB:DORS SC/OEAB:DORS RPB: ADM C/HICB:DRCH

TGreene RDennig* Tech Ed* JWermiel*

/ /93 01/08/93 12/16/92 02/02/93 C/OEAB:DORS C/OGCB:DORS D/DORS

AChaffee GMarcus BGrimes

3 AIMS l l l l

[OFFICIAL RECORD COPY]

DOCUMENT NAME: G:\ATB1\LSIN

IN 93-XX

January xx, 1993 from a buildup and accumulation of crud in the low flow areas of the standard

ports over a period of time. These ports will be flushed in the normal

preventive maintenance of the trip mechanisms during refueling outages.

In Unresolved Safety Issue (USI) A-47, "Safety Implication of Control System

in LWR Nuclear Power Plants," one of the issues was reactor vessel overfill.

The resolution of USI A-47, as outlined in Generic Letter (GL) 89-19, concluded that all plants' procedures and technical specifications should

include provisions to verify periodically the operability of overfill

protection and ensure automatic overfill protection. This resolution rests on

the tripping of the feedwater pumps which did not occur in the LaSalle event.

The operators did follow procedures and closed the MSIVs. This prevented the

filling of the main steam lines past the MSIVs, but the operability of the

reactor core isolation cooling (RCIC) system was impacted.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: T. Greene, NRR

(301) 504-1175 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

OEAB:DORS RS RPB:ADM C/H RCH

TGreene* Tech Ed* JWeAi~iel

12/18/92 I / 0 12/16/92 Z/Z/ ?3 C/OEAB:DORS C/OGCB:DORS D/DORS

AChaffee GMarcus BGrimes

/ / / / / /

OFFICIAL RECORD COPY

DOCUMENT NAME: G:\ATB1\LSIN

IN 93-XX

January xx, 1993 from a buildup and accumulation of crud in the low flow areas of the standard

ports over a period of time. These ports will be flushed in the normal

preventive maintenance of the trip mechanisms during refueling outages.

If

This information notice requires no specific action or written response.

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: T. Greene, NRR

(301) 504-1175 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

OEAB:DORS:NRR SC/OEAB:DORS:NRR RPB: ADM

TGreene RDennig Tech Ed*

I/1 12/16/92 C/OEAB:DORS:NRR C/OGCB:DORS:NRR D/DORS

AChaffee GMarcus BGrimes

/ / / / / /

OFFICIAL RECORD COPY

DOCUMENT NAME: G:\ATB\LSIN

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

4s-e=*of) the technical contactX listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact(s): T. Greene, NRR

(301) 504-1175 Attachment: List of Recently Issued NRC Information Notices

OEAB:DOEA:NRR SC/OEAB:DOEA:NRR RPB:ADM (Tech Branches)

Tech Ed.