Information Notice 1993-54, Motor-Operated Valve Actuator Thrust Variations Measured with a Torque Thrust Cell and a Strain Gage

Motor-Operated Valve Actuator Thrust Variations Measured with a Torque Thrust Cell and a Strain Gage
	ML031210125
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	07/20/1993
From:	Grimes B; Office of Nuclear Reactor Regulation
To:	;
References
	IN-93-054, NUDOCS 9307140106
	Download: ML031210125 (10)
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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 July 20, 1993 NRC INFORMATION NOTICE 93-54: MOTOR-OPERATED VALVE ACTUATOR THRUST VARIATIONS

MEASURED WITH A TORQUE THRUST CELL AND A STRAIN

GAGE

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 a possible error in their diagnostic evaluation

of motor-operated valve (MOV) actuators. 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

Diagnostic testing of MOVs is performed to satisfy the commitments made in

response to NRC Generic Letter (GL) 89-10, "Safety-Related Motor-Operated

Valve Testing and Surveillance," and its supplements. Actuator output thrust

is measured by a combination of transducers. The transducers include, but are

not limited to, the ITI MOVATS torque thrust cell (thrust cell) and the

Teledyne quick stem sensor (stem sensor).

On November 9, 1992, ITI MOVATS engineers working at the Turkey Point plant

noticed that thrust measurements taken with the torque thrust cell were

different from the stem-mounted strain gage readings after the thrust cell was

removed. Review showed that all of the readings of the valves that had been

tested using the stem sensor changed somewhat when the thrust cell was removed

from the valve. Data indicated that thrust readings degraded by approximately

20 percent when the thrust cell was removed.

On November 10, 1992, ITI MOVATS management and a licensee engineer began to

investigate the cause.

Discussion

As discussed above, to meet the commitments made in response to GL 89-10, most

licensees rely on MOV diagnostic equipment to set the thrust delivered by the

actuator in opening or closing its valve. Failure to properly account for

inaccuracies introduced by the use of diagnostic equipment could result in

9307140106 (ID 13 X 05af 3al

.IN 93-54 July 20, 1993 either the MOV not being able to perform its intended safety function because

of inadequate actuator output or the failure of a component in either the

valve or the actuator because of excessive motor torque.

The devices discussed in the

Description of Circumstances

operate on the

following principles:

- The ITI MOVATS torque thrust cell is a radial web calibrated load cell.

The inner ring of the cell is bolted to the top of the valve yoke and

the outer ring to the bottom of the actuator. The rings are connected

by eight webs that have strain gages to measure actuator torque and

thrust simultaneously. Installation of the thrust cell requires that

the actuator be raised a distance equal to the thickness of the thrust

cell. This means that the actuator stem nut is in a new position on the

valve stem.

- The Teledyne quick stem sensor is a strain gage mounted on a strip of

foil with tabs on each end to facilitate Installation on the valve stem.

The sensor comes with leads preconnected to the gage. Epoxy is used to

install the stem sensor on the valve stem.

During the test, the valve is stroked and the thrust cell is used as a

calibration reference for the stem sensor. Once the stem sensor is

calibrated, it can be used for future MOV tests without using the thrust cell.

The Limitorque actuator torque switch is then set to produce the required

valve stem thrust. After the thrust cell is removed, a full valve stroke

signature is obtained to evaluate overall actuator performance.

As a result of their review, ITI MOVATS and licensee personnel concluded that

the most significant contributors to the observed changes in thrust when the

thrust cell was removed are stem engagement and stem lubricant.

- Stem engagements of less than one stem diameter tend to increase the

thrust at torque switch trip by improving the stem factor. This effect

is more pronounced when Neolube is used than when EP-O is used as a stem

lubricant.

- Test results indicate that stroke-to-stroke variations in thrust at

torque switch trip are greater with Neolube than with EP-O. For

Neolube, the variations tend to be high on initial lubrication and then

decrease as the valve is stroked.

In January 1993, ITI MOVATS engineers issued the attached report of their

investigation of the discrepancies in thrust measurements which confirms that

the primary causes are stem lubrication and stem nut wear.

' IN 93-54 July 20, 1993 Related Generic Communications

NRC has issued a number of information notices pertaining to the accuracy of

MOV diagnostic equipment. Most recently, these have included NRC Information

Notice (IN)93-01, "Accuracy of Motor-Operated Valve Diagnostic Equipment

Manufactured by Liberty Technologies;" IN 92-23, "Results of Validation

Testing of Motor-Operated Diagnostic Equipment;" and IN 91-61, "Preliminary

Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment."

NRC also issued Supplement 5 to GL 89-10, "Inaccuracy of Motor-Operated Valve

Diagnostic Equipment," on June 28, 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 project manager.

rian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Francis Jape, RII

(404) 331-5607 Thomas G. Scarbrough, NRR

(301) 504-2794 Attachments:

1. ITI MOVATS Report dated January 1993

2. List of Recently Issued NRC Information Notices

I I At achment 2 IN 93-54 July 20, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

93-53 Effect of Hurricane 07/20/93 All holders of OLs or CPs

Andrew on Turkey Point for nuclear power reactors.

Nuclear Generating

Station and Lessons

Learned

93-52 Draft NUREG-1477, 07/14/93 All holders of OLs or CPs

"Voltage-Based Interim for pressurized water

Plugging Criteria for reactor (PWRs).

Steam Generator Tubes"

93-51 Repetitive Overspeed 07/09/93 All holders of OLs or CPs

Tripping of Turbine- for nuclear power reactors.

Driven Auxiliary Feed- water Pumps

93-50 Extended Storage of 07/08/93 All licensees authorized

Sealed Sources to possess sealed sources.

93-49 Improper Integration of 07/08/93 All holders of OLs or CPs

Software into Operating for nuclear power reactors.

Practices

93-48 Failure of Turbine- 7/6/93 All holders of OLs or CPs

Driven Main Feedwater for nuclear power reactors.

Pump to Trip Because of

Contaminated Oil

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

OL = Operating License

CP = Construction Permit

IN 93-xx

April xx, 1993 Manufactured by Liberty Technologies"; IN 92-23, "Results of Validation

Testing of Motor-Operated Diagnostic Equipment"; and IN 91-61, "Preliminary

Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment."

In addition, NRC is preparing a supplement to GL 89-10 to request that

licensees address potential accuracy problems with MOV diagnostic equipment.

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 project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact(s): Francis Jape, Region II

(404) 331-5540

Thomas G. Scarbrough, NRR

(301) 504-2794 Attachments:

1. ITI MOVATS Report dated January 1993

2. List of Recently Issued NRC Information Notices

SEE PREVIOUS CONCURRENCE love,+

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IN 93-xx

April 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 project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact(s): Francis Jape, Region II

(404) 331-5540

Thomas G. Scarbrough, NRR

(301) 504-2794 Attachments:

1. ITT MOVATS Report dated January 1993

2. List of Recently Issued NRC Information Notices

SEE PREVIOUS CONCURRENCE

OFFICE OGCB:DORS: TECH ED. *RII *RII EMEB:DET

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IN 93-xx

June xx, 1993 Related Generic Communications

NRC has issued a number of information notices pertaining to the accuracy of

MOV diagnostic equipment. Most recently, these have included NRC Information

Notice (IN)93-01, Accuracy of Motor-Operated Valve Diagnostic Equipment

Manufactured by Liberty Technologies;" IN 92-23, 'Results of Validation

Testing of Motor-Operated Diagnostic Equipment;" and IN 91-61, "Preliminary

Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment."

NRC is also preparing Supplement 5 to GL 89-10, "Inaccuracy of Motor-Operated

Valve Diagnostic Equipment."

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 project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact(s): Francis Jape, Region II

(404) 331-5540

Thomas G. Scarbrough, NRR

(301) 504-2794 Attachments:

1. ITI MOVATS Report dated January 1993

2. List of Recently Issued NRC Information Notices

SEE PREVIOUS CONCURRENCE

OFFICE *OGCB:DORS:NRR *TECH ED. *RII I *RII *EMEB:DET

NAME RJKiessel DGable AGibsori FJape TGScarbrough

DATE IC5/04/93 [05/10/93 103/30/93 03/30/93 I05/19/93

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IN 93-54 July 20, 1993 Related Generic Communications

NRC has issued a number of information notices pertaining to the accuracy of

MOV diagnostic equipment. Most recently, these have included NRC Information

Notice (IN)93-01, "Accuracy of Motor-Operated Valve Diagnostic Equipment

Manufactured by Liberty Technologies;" IN 92-23, "Results of Validation

Testing of Motor-Operated Diagnostic Equipment;" and IN 91-61, "Preliminary

Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment."

NRC also issued Supplement 5 to GL 89-10, "Inaccuracy of Motor-Operated Valve

Diagnostic Equipment," on June 28, 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 project manager.

orig /s/'d by BKGrimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Francis Jape, RII

(404) 331-5540

Thomas G. Scarbrough, NRR

(301) 504-2794 Attachments:

1. ITI MOVATS Report dated January 1993

2. List of Recently Issued NRC Information Notices

SEE PREVIOUS CONCURRENCE

OFFICE *OGCB:DORS:NRR *TECH ED. *RII *RII *EMEB:DET

NAME RJKiessel DGable AGibson FJape TGScarbrough

DATE 05/04/93 ae05/10/93 A03/30/93 l 03/2P 3 1 a05/19/93l

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IN 93-xx

April xx, 1993 Manufactured by Liberty Technologies;" IN 92-23, "Results of Validation

Testing of Motor-Operated Diagnostic Equipment;" and IN 91-61, "Preliminary

Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment."

In addition, NRC is preparing a supplement to GL 89-10 to request that

licensees address potential accuracy problems with MOY diagnostic equipment.

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 project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact(s): Francis Jape, Region II

(404) 331-5540

Thomas G. Scarbrough, NRR

(301) 504-2794 Attachments:

1. ITI MOVATS Report dated January 1993

2. List of Recently Issued NRC Information Notices

SEE PREVIOUS CONCURRENCE

OFFICE *OGCB:DORS:NRR *TECH ED. *RII *RII XMEB:DET

NAME RJKiessel DGable TAGibson FJape TGScarbrough

DATE l 05/04/93 l05/10/93 l 03/30/93 , 03/30/93 J 05//J1/93_ l

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JANorberg JERichardson GHMarcus BKGrimes

05/20/93 05/21/93 05/ /93 05/ /93 DOCUMENT NAME: JAPE.IN

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IN 93-xx

April xx, 1993 licensees are adequately addressing the problems associated with MOV

diagnostic equipment inaccuracies, NRC is preparing Supplement 5 to GL 89-10,

"Inaccuracy of Motor-Operated Valve Diagnostic Equipment."

Related Generic Communications