Information Notice 1992-83, Thurst Limits for Limitorque Actuators and Potential Overstressing of Motor-Operated Valves

Thurst Limits for Limitorque Actuators and Potential Overstressing of Motor-Operated Valves

ML031190734
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, 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:	12/17/1992
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-92-083, NUDOCS 9212110089
Download: ML031190734 (12)

I

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 December 17, 1992 NRC INFORMATION NOTICE 92-83: THRUST LIMITS FOR LIMITORQUE ACTUATORS

AND POTENTIAL OVERSTRESSING OF MOTOR-

OPERATED VALVES

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 (1) possible overstressing of motor-operated

valves (MOVs) during operation and testing and (2) reviews by the NRC staff of

programs by two nuclear industry organizations to justify increased limits on

the thrust that Limitorque motor actuators for MOVs can withstand. 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

During inspections of programs developed by licensees in response to Generic

Letter (GL) 89-10, "Safety-Related Motor-Operated Valve Testing and Surveil- lance," and its supplements, the NRC staff has found instances in which

licensees have subjected MOVs to thrust or torque that exceeded their limits.

In June 1992, during an inspection at the Three Mile Island Nuclear Station, Unit 1 (TMI-1), the NRC staff discovered an 8-inch crack in the main housing

of a Limitorque actuator for a safety-related MOV in the steam line to an

emergency feedwater pump. The crack began at a bolt hole for the upper

bearing housing cover of the actuator. Licensee test records indicated that

the actuator had been subjected to thrust above its rating on numerous

occasions over the past few years. Upon disassembling the actuator in late

June 1992, the licensee found two other cracks starting at other bolt holes in

the housing cover. The licensee replaced the actuator. Other licensees have

also informed the NRC staff of actuators that have been damaged at nuclear

power facilities.

Upon testing MOVs, nuclear power plant licensees have found the need to

increase torque switch settings for some MOVs because the torque or thrust

required to operate the valves under differential pressure-and flow conditions

9212110089 /Q_

me '\ I} tJ

IN 92-83 December 17, 1992 was greater than predicted. In certain cases, licensees have set the MOV

torque switch near its maximum allowable setting, which is based on the

structural and electrical capability of the MOV. At these high settings, MOVs

can exceed their torque or thrust ratings because of uncertainties such as

amount of inertia exhibited by the actuator during operation, MOV diagnosticthe

equipment accuracy, and torque switch repeatability. As a consequence, some

licensees have been attempting to justify thrust and torque limits for MOV

actuators greater than the ratings established by the manufacturer, Limitorque

Corporation (Limitorque). The following describes two programs to increase

thrust limits of Limitorque actuators.

Kalsi Engineering

On April 15, 1992, the NRC staff held a public meeting with representatives

Duke Power Company and Kalsi Engineering (Kalsi) to discuss a study by of

Kalsi

of the capability of MOV actuators to withstand thrust greater than the

ratings published by Limitorque. In August 1992, the staff reviewed the

report of the Kalsi study while inspecting the GL 89-10 program at the Wolf

Creek Generating Station.

In its testing program, Kalsi tested one actuator each of sizes SMB-000,

-0, and -1 for 4000 cycles in both the open and close directions, at 200 -00,

percent of the Limitorque thrust ratings of each actuator. The Kalsi testing

included seismic loading conditions for several cycles. In its Technical

Update 92-01, Limitorque has endorsed the Kalsi study, with certain condi- tions, for up to 140 percent of the thrust ratings. In a letter to the

utilities that participated in the study, and hence that-can obtain the

proprietary report, Limitorque has allowed those utilities to rely on the

actuators to withstand thrust of up to 162 percent of the rating for 2000

cycles.

The staff documented a number of concerns about the design of the Kalsi

in a letter to Duke Power Company on June 10, 1992, and NRC Inspection study

50-482/92-15, September 30, 1992, for the Wolf Creek Generating Station.Report

deficiencies identified may affect the reliability of the test results. The

summary of the staff's comments on the Kalsi study can be found in A

Attachment 1.

IN 92-83 December 17, 1992 Westinghouse Corporation

an inspection at

On July 7-9, 1992, the NRC Vendor Inspection Branch conducted intended to

the Westinghouse Corporation (Westinghouse) to review a program greater than their

demonstrate that Limitorque actuators can withstand thrust

published ratings.

-00, and

After comparing actuator parameters, Westinghouse placed the SMB-000,group.

-0 actuators in one group and the SMB-1 and -2 actuators in another

of size

Westinghouse selected an SMB-O0 actuator to represent the actuators the actuators

SMB-000, -00, and -0 and selected an SMB-2 actuator to represent

SMB actuator consisted of an

of size SMB-1 and -2. The plan for each tested a final thrust

initial torque test, mechanical aging tests, a seismic test, tested

overload test, and a final torque test. The test plan required the load

actuators to be operated in the open and close directions under various

conditions for many cycles.

staff

In NRC Inspection Report 99900404/92-01, August 14, 1992, the NRC certain

concluded that the Westinghouse study did not adequately address

the

issues and, therefore, that utilities should not currently be using some of

However, the staff stated that

results from the Westinghouse program. temporary justifi- the data in the test reports could be useful for evaluating

of

cations for the operability of actuators in individual cases. A summary found in

with the Westinghouse program can be

the staff's principal concerns

Attachment 2.

Related Generic Communications

For

The NRC has issued other generic communications on MOV actuators. 92-70,

example, on September 25, 1992, the NRC issued Information Notice

Power

"Westinghouse Motor-Operated Valve Performance Data Supplied to Nuclear the

Plant Licensees," to alert licensees to the possibility of overestimating valve

thrust output capability of actuators when using performance data from

manufacturers.

IN 92-83 December 17, 1992 This information notice requires no specific action or written

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

one of the technical contacts listed below or the appropriate please contact

Nuclear Reactor Regulation project manager. Office of

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Jeffrey B. Jacobson, NRR

(301) 504-2996 Thomas G. Scarbrough, NRR

(301) 504-2794 P. K. Eapen, Region I

(215) 337-5150

Michael F. Runyan, Region IV

(817) 860-8142 Leonard Prividy, Region I

(215) 337-5140

Attachments:

1. Summary of NRC Staff Comments on

the Kalsi Study.

2. Summary of NRC Staff Comments on

the Westinghouse Program

3. List of Recently Issued NRC Information Notices

Q~

Attachment 1 IN 92-83 December 17, 1992 Summary of NRC Staff Comments

on the Kalsi Study

1. Kalsi lubricated the stem more frequently than it would be lubricated in

a normal application. As the lubricant deteriorates over time, the

internal parts may exhibit greater wear than indicated in the Kalsi

results.

2. Kalsi found certain internal components that experienced torque to have

failed or have significant wear.

3. In Technical Update 92-01, Limitorque indicated that the actuator bolts

must be tightened to a certain torque before applying the increased

allowable percentage thrust above the ratings. The Arkansas Power and

Light Company, the licensee for Arkansas Nuclear One, informed the staff

that, after tightening the bolts, the thrust delivered when the torque

switch tripped was up to 50 percent less than the thrust delivered before

tightening the bolts. The licensee stated that it had determined that

the probable cause was the overcompression of the housing cover gasket

caused by the increased torque requirements of the housing cover bolts.

Kalsi is reassessing the need to tighten the bolts to a specific torque

value.

4. Kalsi used new actuators in its testing program, and did not consider

possible differences in manufacturing over the years or the effects of

aging.

5. Kalsi had not ensured that tightening of the actuator bolts after seismic

testing did not affect reliance on the results of the tests for the

remaining cycles.

6. During the April 1992 presentation, Dr. Kalsi stated that the total

number of cycles that an actuator has operated from the beginning of its

life must be counted in the 2000 cycle limit stated in the study.

7. In the Kalsi study, the motor pinion key on some MOVs failed, and the

manual declutch lever spuriously engaged during tests of an actuator.

- 8. The Kalsi study did not ensure that the actuator bolts, stem, or stem nut

had adequate strength for specific plant applications.

II

Attachment 2 IN 92-83 December 17, 1992 Page I of I

Summary of NRC Staff Comments

on the Westinghouse Program

1. Westinghouse did not adequately establish similarity in grouping actua- tors for testing.

2. Westinghouse did not adequately address the margin necessary to account

for statistical variations among actuators within each group of actuators

when sampling only one actuator from each group for testing.

-3. Westinghouse did not clearly indicate that actuator bolts, stem, or stem

nuts were not included in its study.

4. Westinghouse stated that its program may only be applied to actuators for

which the total number of operating cycles and thrust conditions are

known.

5. Westinghouse did not address any margin provided to account for the

inaccuracy of test equipment used in the Westinghouse program or used by

licensees applying thrust allowable limits from the program.

6. Westinghouse had not resolved an issue of spurious engagement of the

manual declutch lever during testing of an actuator.

Attachment 3 IN 92-83 December 17, 1992 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

92-82 Results of Thermo-Lag 12/15/92 All holders of OLs or CPs

330-1 Combustibility for nuclear power reactors.

Testing

92-81 Potential Deficiency 12/11/92 All holders of OLs or CPs

of Electrical Cables for nuclear power reactors.

with Bonded Hypalon

Jackets

92-80 Results of Thermo-Lag 12/07/92 All holders of OLs or CPs

330-1 Combustibility for nuclear power reactors.

Testing

92-79 Non-Power Reactor 12/01/92 All holders of OLs or CPs

Emergency Event Response for test and research

reactors.

92-78 Piston to Cylinder 11/30/92 All holders of OLs or CPs

Liner Tin Smearing on for nuclear power reactors.

Cooper-Bessemer KSV

Diesel Engines

92-77 Questionable Selection 11/17/92 All holders of OLs or CPs

and Review to Deter- for nuclear power reactors.

mine Suitability of

Electropneumatic Relays

for Certain Applications

92-76 Issuance of Supple- 11/13/92 All holders of OLs or CPs

ment 1 to NUREG-1358, for nuclear power reactors.

"Lessons Learned from

the Special Inspection

Program for Emergency

Operating Procedures

(Conducted October 1988 -

September 1991)"

92-75 Unplanned Intakes of 11/12/92 All holders of OLs or CPs

Airborne Radioactive for nuclear power reactors.

Material by Individuals

at Nuclear Power Plants

OL =.Operating License

CP = Construction Permit

11J IN 92-83 December 17, 1992 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. /

Original Signed

-

Briani

Li I r ,'- zI -K

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Jeffrey B. Jacobson, NRR

(301) 504-2996 Thomas G. Scarbrough, NRR

(301) 504-2794 P. K. Eapen, Region I

(215) 337-5150

Michael F. Runyan, Region IV

(817) 860-8142 Leonard Prividy, Region I

(215) 337-5140

Attachments:

1. Summary of NRC Staff Comments on

the Kalsi Study.

2. Summary of NRC Staff Comments on

the Westinghouse Program

3. List of Recently Issued NRC Information Notices

Document Name: 92-83. IN

• SEE PREVIOUS CONCURRENCES

• OGCB:DORS:NRR *TECH ED ISIB:DRIL:NRR *C/RSIB:DRIL:NRR *D/DRIL:NRR

RJKiessel:mkm JMain )BJacobson EVImbro CERossi

10/19/92 10/21/92 [1/02/92 11/03/92 11/04/92

• EMEB:DE:NRR *C/EMEB:DE:NRR *D/DE:NRR *C/OGCB:DORS:NRR

TGScarbrough JANorberg JERichardson GHMarcus G2s

11/10/92 11/17/92 11/17/92 12/08/92 12/qc/92

IN 92- December , 1992 In NRC Inspection Report 99900404/92-01, August 14, 1992, the NRC staff

concluded that the Westinghouse study did not adequately address certain

issues, and therefore, that utilities should not currently be using the

results from the Westinghouse program. However, the staff stated that some of

the data in the test reports could be useful for evaluating temporary justifi- cations for the operability of actuators in individual cases. A summary of

the staff's principal concerns with the Westinghouse program can be found in

Attachment 2.

Related Generic Communications

The NRC has issued other generic communications on MOV actuators. For

example, on September 25, 1992, the NRC issued Information Notice 92-70,

"Westinghouse Motor-Operated Valve Performance Data Supplied to Nuclear Power

Plant Licensees," to alert licensees to the possibility of overestimating the

thrust output capability of actuators when using performance data from valve

manufacturers.

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 Contacts: Jeffrey B. Jacobson, NRR

(301) 504-2996 Thomas G. Scarbrough, NRR

(301) 504-2794 Dr. P. K. Eapen, Region I

(215) 337-5150

Michael F. Runyan, Region IV

(817) 860-8142 Leonard Prividy, Region I

(215) 337-5140

Attachments: see page 4 Document Name: NRCIN.283 *SEE PREVIOUS CONCURRENCES

• OGCB:DORS:NRFt *TECH ED *RSIB:DRIL:NRR *C/RSIB:DRIL:NRR kD/DRIL:NRR

RJKiessel :mkm JMain JBJacobson EVImbro CERossi

10/19/92 10/21/92 11/02/92 11/03/92 11/04/92

• EMEB:DE:NRR *C/EMEB:DE:NRR *D/DE:NRR C/OGCB:DORS:NRR D/DORS:NRR

TGScarbrough JANorberg JERichardson GHMarcus BKGrimes

11/10/92 11/17/92 11/17/92 1),/ /92M 11/ /92

IN 92- November , 1992 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 Contacts: Jeffrey B. Jacobson, NRR

(301) 504-2996 Thomas G. Scarbrough, NRR

(301) 504-2794 Dr. P. K. Eapen, Region I

(215) 337-5150

Michael F. Runyan, Region IV

(817) 860-8142 Leonard Prividy, Region I

(215) 337-5140

Attachment: List of Recently Issued NRC Information Notices

Document Name: NRCIN.283

• SEE PREVIOUS CONCURRENCES

• OGCB:DORS:NRR *TECH ED *RSIB:DRIL:NRR *C/RSIB:DRIL:NRR *D/DRIL:NRR

RJKiessel :mkm JMain JBJacobson EVImbro CERossi

10/19/92 10/2 /92 11/02/92 3/92 11/04/92

• EMEB:DE:NRR C/,t.J:NRR D/DE:NR ' C/OGCB:DORS:NRR D/DORS:NRR

TGScarbrough J JERichar W GHMarcus BKGrimes

11/10/92 11// 92 11/1792V 11/ /92 11/ /92

v'

IN 92- October , 1992 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 Contacts: Jeffrey B. Jacobson, NRR

(301) 504-2996 Thomas G. Scarbrough, NRR

(301) 504-2794 Dr. P. K. Eapen, Region I

(215) 337-5150

Michael F. Runyan, Region IV

(817) 860-8142 Leonard Prividy, Region I

(215) 337-5140

Attachment: List of Recently Issued NRC Information Notices

Document Name: NRCIN.283

• SEE PREVIOUS CONCURRENCES Krai

• OGCB:DORS:NRR

RSI~fiA

• TECH ED RSIB: RR CRSV

RR D/DRIL:NRR

RJKiessel:mkm JMain JBJa son R IW o tv CERossi

10/19/92 10/21/92 10/2 /92 M 1M/3 /92 N10/ z/92 EMEB<RJ'£ RR C/EMEB:DE:NRR D/DE:NRR C/OGCB:DORS:NRR D/DORS:NRR

r

TGSfarough JANorberg JERichardson GHMarcus BKGrimes

10/ /92 Iv/t 10/ /92 10/ /92 10/ /92

The NRC has issued other generic communications providing information on MOV

actuators. For example, NRC issued Information Notice 92-70, "Westinghouse

Motor-Operated Valve Performance Data Supplied to Nuclear Power Plant Licens- ees," (September 25, 1992) to alert licensees to the possibility of overstres- sing the thrust output capability of actuators when using performance data

from valve manufacturers.

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 Contacts: see page 5 Document Name: NRCIN.283 OGCB:DORS:NRR TECH ED RSIB:DRIL:NRR C/lRSIB:DRIL:NRR D/DRIL:NRR

RJKiessel:mkrn 3Tphin JBJacobson EVImbro CERossi

10/19/92 A 10/21/92 10/ /92 10,/ /92 10/ /92 EMEB:DE:NRR C/EMEB:DE:NRR D/DE:NRR C/OGCB:DORS:NRFt D/DORS:NRR

TGScarbrough JANorberg JERichardson GHMarcus BKGrimes

10/ /92 10/ /92 10/ /92 10/ /92 10/ /92