Information Notice 1992-23, Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment

Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment
	ML031200445
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Crane
Issue date:	03/27/1992
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-92-023, NUDOCS 9203230070
	Download: ML031200445 (8)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555

March 27, 1992

NRC INFORMATION NOTICE 92-23: RESULTS OF VALIDATION TESTING OF MOTOR-OPERATED

VALVE DIAGNOSTIC EQUIPMENT

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors and all vendors of motor-operated valve (MOV) diagnostic equipment.

Purpose

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

to alert addressees to the final results of validation testing of MOV diagnos- tic equipment conducted for the MOV Users Group (MUG) of nuclear power plant

licensees.

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.

Background

In 1990, the MUG initiated a program to conduct tests-of MOV diagnostic equip- ment to validate the accuracy asserted by the equipment vendors. The MUG

requested the Idaho National Engineering Laboratory (INEL) to provide a test

stand for the program.

The NRC Office of Nuclear Regulatory Research (RES)

provided funds for INEL to participate, with the stipulation that the results

of the testing would be made available to the NRC and the public.

The

MOV diagnostic equipment vendors participating in the MUG test program were

ASEA-Brown Boveri (ABB) Impell, ITI-MOVATS, Liberty Technologies, Siemens/KWU,

Teledyne, and Wyle Laboratories. The INEL test stand included a Limitorque

motor operator which pushes a valve stem into a water reservoir with a com- pressed air overcharge, providing various loading conditions on the valve

stem.

INEL obtained accurate measurements of thrust using a stem-mounted load

cell as a reference standard. Each diagnostic equipment vendor installed and

operated its own equipment to measure various parameters so as to obtain

estimates of stem thrust.

At a public meeting on July 30, 1991, the MUG released a progress report of its

program to validate the accuracy of MOV diagnostic equipment.

During the

meeting, the MUG stated that licensees and diagnostic equipment vendors should

review the progress report for its applicability to MOVs installed in nuclear

power plants. The MUG also alerted licensees and diagnostic equipment vendors

to their responsibilities under Part 21 of Title 10 of the

Code of Federal Regulations (10 CFR Part 21).

The NRC issued Information

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IN 92-23 March 27, 1992 Notice 91-61 (September 30, 1991),

"Preliminary Results of Validation Testing

of Motor-Operated Valve Diagnostic Equipment," to alert licensees to the issues

raised by the MUG progress report.

Description of Circumstances

-

At a public meeting on February 3, 1992, the MUG released "Final Report - MUG

Validation .Testing as Performed at Idaho National Engineering Laboratories

(Volume 1)."

The report has been placed in the NRC Public Document Room (PDR),

2120 L Street, N.W., Washington, D.C. 20555 (telephone (202) 634-3273).

Upon

receiving the remaining three volumes, which will provide data traces, test

documentation, and torque measurement information, the staff will place these

volumes in the PDR.

On March 4, 1992, the NRC staff discussed the MUG final

report with members of the MUG committee that conducted the validation program.

The MUG final report presents the findings of the validation program and

specifies whether or not the tested diagnostic equipment provided the accuracy

claimed by its vendors in predicting stem thrust.

The MUG final report indi- cates that the MOV diagnostic equipment that relied on spring pack displacement

to estimate stem thrust did not meet the accuracy claims of its vendors.

MOV diagnostic equipment that relied on other parameters such as stem or yoke

strain was shown, in general, to meet the applicable accuracy claims, although

certain equipment did not meet the accuracy claims in certain individual tests.

ABB Impell and ITI-MOVATS are two MOV diagnostic equipment vendors that have

equipment commercially available that relies on spring pack displacement to

estimate-stem-thrust.- At the-MUG- meetingv 4n Febru-ar-y 1992, ABB Impel 1 repre- sentatives stated that they would work with their two licensee customers to

develop new accuracy values.

On March 2, 1992, the NRC staff held a public

meeting with representatives of ITI-MOVATS to discuss the accuracy of the

thrust measuring device (TMD) used by ITI-MOVATS' to estimate stem thrust based

on 'spring pack displacement.

During the meeting on March 2, the representa- tives of ITI-MOVATS described the results of their own field validation program

that had been initiated to address the preliminary concerns raised in the MUG

progress report.

However, the ITI-MOVATS program addressed only the accuracy

of the TMD under static (zero differential pressure and flow) conditions and

not the accuracy of this equipment under differential pressure and flow condi- tions.

Nevertheless, the results of the field validation program showed that

the inaccuracy of the TMD may be larger than assumed in some instances by

licensees. The ITI-MOVATS representatives also discussed the results of their

efforts to resolve concerns regarding the fact that the TMD is calibrated in

the valve opening direction, but is also used to predict the thrust delivered

by the actuator in the valve closing direction. Although this study of valve

directional effect by ITI-MOVATS focused on static conditions, the study

indicated that the effect of the direction that the valve moves could increase

significantly the uncertainty of the TMD.

Discussion

Many licensees rely on MOV diagnostic equipment to provide information on the

thrust required to open or close the valve and on the thrust delivered by the

motor actuator.

The various types of MOV diagnostic equipment estimate valve

stem thrust using different parameters, such as the displacement of the spring

IN 92-23 March 27, 1992 pack or the strain in the stem, mounting bolts, or yoke. Some licensees make

decisions regarding the operability of safety-related MOVs based on the thrust

information obtained from the diagnostic equipment.

Therefore, the use of

MOV diagnostic equipment can affect significantly the safe operation of a

nuclear power plant.

The MUG validation program indicated that the accuracy of MOV diagnostic

equipment that relies on spring pack displacement has not been verified to be

within its original stated accuracy under differential pressure and flow

conditions.

Further, the field validation program and valve directional effect

study by ITI-MOVATS have shown an increase in the uncertainty of this

MOV diagnostic equipment under static conditions. Therefore, licensees who use

MOV diagnostic equipment that relies on spring pack displacement to make

decisions regarding the capability of MOVs to operate under design-basis

conditions may have overestimated the capability of those MOVs. A particular

concern arises where a licensee has lowered the torque switch settings of its

MOVs below the settings recommended by the actuator manufacturer based on

thrust estimates from diagnostic equipment during tests conducted under static

or partial design-basis differential pressure conditions.

The NRC will address each case individually for MOV diagnostic equipment that

was not included in the MUG validation program.

For example, the concerns

regarding the accuracy of MOV diagnostic equipment that relies on spring pack

displacement apply to all commercial or plant-specific MOV diagnostic equipment

that relies on spring pack displacement to estimate stem thrust.

Similar con- cerns might be present for other MOV diagnostic equipment that also predicts

stem thrust by indirect means, such as spring pack force.

"Load-sensitive behavior" in an MOV has been shown to result in less thrust

delivered by the actuator under differential pressure conditions than delivered

under static conditions.

"Load-sensitive behavior" is independent of the type

of MOV diagnostic equipment used and such behavior can lead licensees to

overestimate the capability of their MOVs.

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.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Thomas G. Scarbrough, NRR

(301) 504-2794

Edmund J. Sullivan, Jr., NRR

(301) 504-3266 Attachment:

List of Recently Issued NRC Information Notices

Attachment

IN 92-23

March 27, 1992

Page I of I

LIST OF RECENTLY ISSUED

NRC INFORI4ATION NOTICES

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Information

Date of

Notice No.

Subject

Issuance

Issued to

92-22 Criminal Prosecution and

03/24/92

All holders of OLs or CPs

Conviction of Wrongdoing

for nuclear power reactors.

Committed by A Commercial-

Grade Valve Supplier

92-21 Spent Fuel Pool Reactivity

03/24/92

All holders of OLs or CPs

Calculations

for nuclear power reactors.

92-20

Inadequate Local Leak Rate

03/03/92

All holders of OLs or CPs

Testing

for nuclear power reactors.

92-19 Misapplication of Potter &

03/02/92 All holders of OLs or CPs!

Brumfield MDR Rotary Relays

for nuclear power reactors.

92-18 Potential for Loss of Re-

02/28/92

All holders of OLs or CPs

mote Shutdown Capability

for nuclear power reactors.

during A Control Room Fire

92-17 NRC Inspections of Pro-

02/26/92 All holders of OLs or CPs.

grams being Developed at

for nuclear power reactors.

Nuclear Power Plants in

Response to Generic

Letter 89-10

92-16 Loss of Flow from the

02/25/92 All holders of OLs or CPs!

Residual Heat Removal

for nuclear power reactors.

Pump during Refueling

Cavity Draindown

92-15 Failure of Primary System

02/24/92

All holders of OLs or CPs

Compression Fitting

for nuclear power reactors .

92-14 Uranium Oxide Fires at Fuel

02/21/92

All fuel cycle and uranium

Cycle Facilities

fuel research and development

licensees.

OL - Operating License

CP = Construction Permit

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IN 92-23 March 27,

1992 pack or the strain in the stem, mounting bolts, or yoke. Some licensees make