Information Notice 1993-74, High Temperatures Reduce Limitorque AC Motor Operator Torque

High Temperatures Reduce Limitorque AC Motor Operator Torque

ML031070330
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:	09/16/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-074, NUDOCS 9309100374
Download: ML031070330 (11)

K-/UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 September

16, 1993 NRC INFORMATION

NOTICE 93-74: HIGH TEMPERATURES

REDUCE LIMITORQUE

AC MOTOR OPERATOR TORQUE

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

that high ambient temperatures

can reduce ac motor torque capability

in Limitorque

motor operators.

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 requiyements;

therefore, no specific action or written response is required.Background

In order to size a motor operator to a given valve, the expected operator torque capable of being developed

under design-basis

conditions

is calculated.

The operator torque output is directly related to the torque output of the operator motor. For dc motor operators, Limitorque

has published

derating factors that are applied to high ambient temperature

applications.

However, until recently, no derating information

was available

for Limitorque

motor operators

equipped with ac motors.DescriDtion

of Circumstances

In response to NRC questions, Limitorque

Corporation

established

a test program to evaluate whether elevated ambient temperatures

could significantly

affect ac motor output torque. In October of 1992, Limitorque

completed testing of five ac motors. This testing indicated

that ac motor stall torque values decreased

significantly

with increasing

ambient temperatures.

The measured torque reductions

ranged from 14 to 25 percent for ambient temperature

increases

from 24°C [75°F] to 169 0 C [336*F]. Limitorque

contracted

with its main motor supplier, Reliance Motor Co., to calculate

the expected stall torque reduction

for all Limitorque/Reliance

ac motor designs.On May 13, 1993, Limitorque

issued a report about a potential

10 CFR Part 21 condition.

The report contained

a tabulation

of motor types and expected torque reductions

for ambient temperature

increases

from 25*C [77 0 F] to 180 0 C 9309100374 x IotNc4 c 2~°>10?- /I.c

IN 93-74'September

16, 1993 [356°F]. This data is given in Attachment

1. Limitorque

has since indicated that the torque reductions

would be applicable

only for motors in ambient conditions

above 40*C [104 0 F] as the motors are designed to deliver full rated torque up to 40C [104'F].Limitorque

has stated that the torque reduction

is linear with respect to temperature.

The Limitorque

table also contains information

on the expected reduction

in locked rotor current at elevated temperatures.

The reduced locked rotor current would provide a slightly higher motor terminal voltage.Although this would improve the calculated

reduced voltage motor performance, it would not compensate

for the torque reduction

resulting

from an elevated temperature.

Limitorque

further stated that motor temperature

rise as a result of prior motor energization

and motor run time (valve stroke time) must be accounted

for.Additional

information

concerning

motor operator performance

can be found in NRC Inspection

Report 99900100/93-01 issued 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 (NRR) project manager.ast @ A, Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Jeffrey B. Jacobson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Attachments:

1. Current/Torque

Changes from 25 to 180 Centigrade

2. List of Recently Issued NRC Information

Notices

-IN 93-74 September

16, 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.Orignal signed by Al Chaffee for/Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts: Jeffrey B. Jacobson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Attachments:

1. Current/Torque

Changes from 25 to 180 Centigrade

2. List of Recently Issued NRC Information

Notices* r~a Prcovimic~

Cnnrijrr~nrP

OFFICE: *RSIB:DRIL

• SC:RSIB:DRIL

• C:RSIB:DRIL

• D:DRIL:NRR

NAME: JBJacobson

DPNorkin EVImbro CERossi DATE: 08/12/93 08/12/93 08/13/93 08/16/93._ , _ _ ,__ , -, _ _ ., _ ..1 OFFICE: *EMEB:DE *OGCB:DORS

• Tech Ed *C:OGCB:DORS

D:DgRW R NAME: TGScarbrough

RJKiessel

DGable GHMarcus BKGrimes DATE: 1 08/23/93 09/01/93 09/01/93 09/08/93 09//193 Document Name: 93-I4.IN

Attacment

1 IN 93-74 September

16, 1993 Curiznt/Torque

Changes from 25 to 180 Centigrade

'a#1 P8 2'#/1800 5'#/1800 5'#/1800 7.5'#J1800

10'#/1800 15'#/1800 25'#/1800 40'#/1800 60'#/1800 60'#/1800 80'#/1800 100'#/1800

200'#/1800

250'#/1800

300'#I1800

2'#/3600 5'#13600 5'#/3600 7.5'#/3600

10'#13600 15'#/3600 25'#13600 40'#/3600 40'#/3600 60'#/3600 80'#/3600 100'#/3600

150'#/3600

200'#/3600

250'#/3600

300'#/3600

400'#/3600

Frame 56 48 56 56 56 56 56 56 58 180 210 210 256 256 326 48 48 56 56 56 56 56 56 180 210 210 256 256 326 326 326 365 Mu2e3#M2735A M2734 M1658 M2925 M1468 M1476 M1480 M1488 M5204 SK-59454 SK-59423 SK-59419A SK-4177 SK-34193 SK-34183 413018-03 M199 M1454 M1457 M1458 M1460 M1463 M4635 SK-59450 SK-59446 SK-59448 SK-34176 SK-34184 SK-34188 SK-34173 SK44171 SK44800-% Current 27.8%29.0%21.8%22.4%26.9%23.7%23.1%21.1%20.8%19.6%16.1%17.0%13.5%11.8%11.7%28.3%27.7%24.7%27.6%23.5%19.2%16.2%27.9%16.2%18.2%18.0%14.1%13.9%10.5%9.3%10.8%8.8%% Torq Loss 20.7%18.6%21.9%5.7%27.7%23.1%23.2%23.4%20.9%18.2%15.8%13.1%9.0%6.9%5.8%16.0%18.5%26.8%16.7%30.8%21.4%24.1%15.9%11.8%16.5%18.3%9.8%10.0%3.4%3.4%2.9%-1.8%'

I n Z b C)*0--:0 0 N m CQ)m C '0 0 Z a o02-I Xn =o (30 (0 o _1 o0c o- 0 V-1 ow z -Attachment

2 IN 93-74 September

16. 1993 Page I of I LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Date of Information

Notice No. Subject 93-73 Criminal Prosecution

of Nuclear Suppliers

for Wrongdoing

93-72 Observations

from Recent Shutdown Risk and Outage Management

Pilot Team Inspections

93-71 Fire at Chernobyl

Unit 2 93-70 Degradation

of Boraflex Neutron Absorber Coupons 93-69 Radiography

Events at Operating

Power Reactors licensees.

93-68 Failure of Pump Shaft Coupling Caused by Temper Embrittlement

during Manufacture

92-16, Loss of Flow from the Supp. 2 ResIdual Heat Removal Pump during Refueling Cavity Oraindown 93-67 Bursting of High Pressure Coolant Injection

Stem Line Rupture Discs Injures Plant Personnel 93-66 Switchover

to Hot-Leg Injection

Following A Loss-of-Coolant

Accident in fres-surized Water Reactors'I L Operat'ng

License CP

• Construction

Permit Issuance Issued to 09/15/93 All NRC licensees.

09/14/93 All holders of OLs or CPs for nuclear power reactors.09/13/93 All holders of OLs or CPs for nuclear power reactors.09/10/93 All holders of OLs or CPs for nuclear power reactors.09/02/93 All holders of OLs or CPs for nuclear power reactors and all radiography

09/01/93 All holders of OLs or CPs for nuclear power reactors.08/23/93 All holders of OLs or CPs for nuclear power reactors.08/16/93 All holders of OLs or CPs for nuclear power reactors.(08/16/93 All holders of OLs or CPs for pressurized

water reactors.

IN 93-xx September

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: Jeffrey B. Jacobson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Enclosures:

1. Current/Torque

Changes from 25 to 180 Centigrade

2. List of Recently Issued NRC Information

Notices* C^i^ Dy-pA,4wIc

rnnemitronra

OFFICE: *RSIB:DRIL

• SC:RSIB:DRIL

I *C:RSIB:DRIL

• D:DRIL:NRR

NAME: JBJacobson

DPNorkin EVImbro CERossi nATr.no ii 9 /02 Rl/I 2 /IQ 08/13/93 08/16/93 I I L. I Ia S. rIe .r I ,_ -- I --, OFFICE: *EMEB:DE _ *OGCB:DORS

• Tech Ed C:OGCB:_ORS

D:DORS:NRR

NAME: TGScarbrough

RJKiessel

DGable GHMarCus K BKGrimes DATE: 1 08/23/93 9/ 1/93 9/ 1/93 9/,?/93 9 Document Name: NKL1IN.3!0

for.Additional

information

concerning

motor operator performance

can be found in NRC kIspection

/eport 99900100/93-01 issued 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 (NRR) project manager.Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Jeffrey B. Jacobson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Enclosures:

1. Current/Torque

Changes from 25 to 180 Centigrade

2. List of Recently Issued NRC Information

Notices Document Name: nrcin.391* Previously

Concurred OFFICE: *RSIB:DRIL

• SC:RSIB:DRIL

• C:RSIB:DRIL

• D:DRIL:NRR

NAME: JBJacobson

DPNorkin EVImbro CERossi nATFP e I 0lR12/QA I n8/12/93 I 08/13/93 1 08/16/93 VF_ IL._ I ___- __ __ _ __ _ ___I____ ___ ____ __ --T --__ _ _OFFICE: *EMEB:DE OGCB:DORV

gTech Ed C:OGCB:DORS

D:DORS:NRR

NAME: TGScarbrough

RJKiesse __77___ GHMarcus BKGtimes DATE: 08/23/93 09/) /93 09// /93 09/ /93 09/l g 3 IN 93-XX August 18, 1993 On May 13, 1993, Limitorque

issued a "Potential

10 CFR 21 Condition" report which contained

a tabulation

of motor types and expected torque reductions

for ambient temperature

increases

from 250C to 1800C. This tabulated

data is attached as Enclosure

(1). Limitorque

has since Indicated

that the torque reductions

would only be applicable

for motors in ambient conditions

above 40°C as the motors are designed to deliver full rated torque up to 40C.Limitorque

has stated that the torque reduction

is linear with respect to temperature.

The Limitorque

table also contains information

on the expected reduction

in locked rotor current at elevated temperatures.

The reduced locked rotor current would provide a slightly higher motor terminal voltage.This would improve the calculated

reduced voltage motor performance, however, not nearly enough to compensate

for the torque reduction

due to elevated temperature.

Also, Limitorque

stated that motor temperature

rise due to prior motor energization

and motor run time (valve stroke time) must be accounted for.Additional

information

concerning

motor operator performance

can be found in NRC inspection

report 99900100/93-01 issued 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 (NRR) project manager.Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Jeffrey B. Jacobson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Enclosure

1: Current/Torque

Changes from 25 to 180 Centigrade

Distribution:

JBJacobson

DPNorkin EVImbro RPZimmerman

CERossi BKGrimes Central Files DOEA R/F RSIB R/F* Previously

Concurred_

I OFFICE: RSIB:DRIL

SC:RSIB:DRIL

TECH EDITOR C:RSIB:DRIL

NAME: JBJacobson*

DPNorkin*

EVImbro*DATE: 08/12/93 08/12/93 08/ /93 08/13/93 OFFICE: D:DRIL:NRR

E D:DOEA:NRR

NAME: CERossi* TGScarbrough

BKGrimes l DATE:_08/16/93

08/1930 /93 I 08/ /93 8 As .-n^rllrMKIT

UMAME. * \ TJFnNfnT .1R.1 OFFICIAL RECORD COPY UVI-WIL11 I IVIVIL. U. N &I'll %#law I .---

IN 93-XX August 13, 1993 On May 13, 1993, Limitorque

issued a 'Potential

10 CFR 21 Condition 3 report which cottlined

a tabulation

of motor types and expected torque reductions

for ambient temperature

increases

from 25"C to 180"C. This tabulated

data is attached as Enclosure

(1). Limitorque

has since indicated

that the torque reductions

wouMd only be applicable

for motors in ambient conditions

above 400C as the moto.ds are designed to deliver full rated torque up to 40*C.Limitorque

has stat that the torque reduction

is linear with respect to temperature.

The torque table also contains information

on the expected reduction

in locked rotor current at elevated temperatures.

The reduced locked rotor current wou'd provide a slightly higher motor terminal voltage.This would improve the cal ulated reduced voltage motor performance, however, not nearly enough to compen ate for the torque reduction

due to elevated temperature.

Also, Llmitorq stated that motor temperature

rise due to prior motor energizatlon

and motor r time (valve stroke time) must be accounted for.Additional

Information

concerning

tor operator performance

can be found in NRC inspection

report 99900100/93-01 ssued June 28, 1993.This information

notice requires no spe ific action or written response.

If you have any questions

about the informa on in this notice, please contact one of the technical

contacts listed belo or the appropriate

Office of Nuclear Reactor Regulation (NRR) project ma ger.Brian K. Gmines, Director 1 .Division of Operat Office of Nucear Reactor Regulation

Technical

contacts:

Jeffrey B. Jacboson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Enclosure

1: Current/Torque

Changes from 25 to 180 Centlgr e Distribution:

JBJacobson

DPNorkin EVImbro RPZlmmerman

CERossi BKGrimes Central Files DOEA R/F RSIB R/F \* Previously

Concurred OFFICE: RSIB:DRIL

/ SC:RSIB:DRIL

TECH EDITOR C:RSIB:oRIL

NAME: JBJacobson*

DPNorkin*

EVImbro*DATE: 0812/93 [08/12/93

08/ /93 08/13/93 OFFICE: D:DRIL:NRR

D:DOEA:NRR

lNAME: C05; BKGrimes DATE: 08//ip93 08/ /93 I__Tat ______ __.____OFFICIAL RECORD COPY DOUMENT NAME: G ;\ INFONO I .d JJ

IN 93-XX August 13, 1993 0 May 13, 1993, Limitorque

issued a 'Potential

10 CFR 21 Condition" report whi contained

a tabulation

of motor types and expected torque reductions

for amble t temperature

increases

from 250C to 1800C. This tabulated

data is attach as Enclosure

(1). Limitorque

has since indicated

that the torque reductio would only be applicable

for motors in ambient conditions

above 400C as th motors are designed to deliver full rated torque up to 400C.Limitorque

h stated that the torque reduction

is linear with respect to temperature.

e Limitorque

table also contains information

on the expected reduction

in 1c -ted rotor current at elevated temperatures.

The reduced locked rotor curr t would provide a slightly higher motor terminal voltage.This would improve he calculated

reduced voltage motor performance, however, not nearly enough to ompensate

for the torque reduction

due to elevated temperature.

Also, Iitorque stated that motor temperature

rise due to prior motor energization

and tor run time (valve stroke time) must be accounted for.Additional

information

conce ing motor operator performance

can be found in NRC inspection

report 99900100 3-01 issued June 28, 1993.This information

notice requires specific action or written response.

If you have any questions

about the in Qrmation in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) proJed4 manager.Brian .Grimes, Director Divisioh of Operation

Events Assessment

Office o#?Nuclear

Reactor Regulation

Technical

contacts:

Jeffrey B. Jacboson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Enclosure

1: Current/Torque

Changes from 25 to 180 Cent grade Distribution:

JBJacobson

DPNorkin EVImbro RPZimmerman

CERossi BKGrimes Central Files DOEA R/F RSIB R/F* Previously

Concurred

_OFFICE: RSIB:DRIL

SC:RSIB:DRIL

TECH EDITOR C:RSIB'.-DRIL

NAME: JBJacobson*

DPNorkin*

Vlmbro DATE: 08/12/93 08/12/93 08/ /93 08 93 OFFICE: D:DRIL:NRR

D:DOEA:NRR

_NAME: CERossi BKGrimes DATE: 08/ /93 08/ /93 ___________

_____________

OFFIIAL ECOR LUP UULI.Ip4in

i mIir IE 1-; u;zeu1u,.uuu

1 OFFICIAL RECORD COPY UU6UMtNj MM; U;\JL11rV1'4V1.VUU

IN 93-XX August 12, 1993 On Ma 13, 1992, Limitorque

issued a "Potential

10 CFR 21 Condition" report which ontained a tabulation

of motor types and expected torque reductions

from 25 to 1800C. This tabulated

data is attached as Enclosure

(1).Limitorqu

has since indicated

that the torque reductions

would only be applicable

or motors in ambient conditions

above 40eC as the motors are designed to eliver full rated torque up to 40C.Limitorque

has lso stated that the torque reduction

is linear with respect to temperature.

Th Limitorque

table also contains information

on the expected reduction

in locatd rotor current at elevated temperatures.

The reduced locked rotor curren would provide a slightly higher motor terminal voltage.This would improve t calculated

reduced voltage motor performance, however, not nearly enough to mpensate for the torque reduction

due to elevated temperature.

Also, LimUtorque

stated that motor temperature

rise due to prior motor energization

and m or run time (valve stroke time) must be accounted for.Additional

information

conce ing motor operator performance

can be found in NRC inspection

report 99900100 3-01 Issued June 28, 1993.This information

notice requires o specific action or written response.

If you have any questions

about the i formation

in this notice, please contact one of the technical

contacts liste below or the appropriate

Office of Nuclear Reactor Regulation (NRR) pro ct manager.Brian K. Grimes, Director Divisi of Operation

Events Assessment

Office Nuclear Reactor Regulation

Technical

contacts:

Jeffrey B. Jacboson, NRR (301) 504-2977 Thomas G. Scarbrough, NRR (301) 504-2794 Enclosure

1: Current/Torque

Changes from 25 to 180 Ce tigrade Distribution:

JBJacobson

DPNorkin EVImbro RPZimmerma

CERossi BKGrimes Central Files DOEA R/F RSIB R/F OFFICE: RSIB:DRIL

RIL TECH EDITOR RSI:DRILlNAME: JBJacobJ0#

r o Hhtnbk DATE: 108/)I J_____ _93 08/ /93 08/ 939 OFFICE: D:DRIL:NRR

D:DOEA:NRR

m NAME: CERossi BKGrimes \DATE: 08/ /93 08/ /93 \nfFITTlAI

DFrnR) rAYDV HlAlIIMFCT

WAMF-. n. TUFlAflT Io"I...... ovrd -o-v wvv I u'.J'.uIEIcn1 I *leriL. U. X LIS I % UVI .U IV