ML20073K886

Part 21 Rept Re Discrepancy Noted Between Torque Indicated by motor-actuator Characterization Sys & Output Torque Measured by Limitorque Actuator Test Stand.Initially Reported on 910426.Vendor Contacted Re Software Problem

ML20073K886
Person / Time
Site:	Brunswick
Issue date:	04/29/1991
From:	Spencer J CAROLINA POWER & LIGHT CO.
To:	Murley T Office of Nuclear Reactor Regulation
References
REF-PT21-91 BSEP-91-0191, BSEP-91-191, NUDOCS 9105130109
Download: ML20073K886 (5)

Text

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CF&L -

Carolina Power & Light Company-4 Brunswick Nuclear Project l P.-O. Box 10429 .

i Southport, NC 28461-0429 i

? April 29, 1991 l

i i FILE: B09-13520 10CFR21 l SERIAL:. BSEP/91-0191 i

i Mr. Thomas E. Murley, Director ,

! Office of Nuclear Reactor Regulation 1 White Flint North 11555 Rockville Pike j Rockville, Maryland 20852 i BRUNSWICK STEAM ELECTRIC PLANT UNITS 1 AND 2 i DOCKET NO. 50-325 AND 50-324

LICENSE NO. DPR-71 AND DPR-62 I NOTIFICATION OF A 10CFR21 REPORTABLE OCCURRENCE

Dear Mr. Murley:

l i This confirms the telephone conversation at 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br /> on April 26, i 1991 between Mr. Robert Pettis (of your staff) and Mr. Michael Foss l (of my staff) which satisfied the requirements of 10CFR21 reporting l criteria. It-reported an apparent deviation in the software used to

test Limitorque SMB-00 actuators, that was supplied by Limitorque.

, Corporation for use with its Motor Actuator Characterization (MAC) l Systems. --

t l

l i

l Very truly yours, y,

i t

hd.9We$k. '

J. W. Spencer, General Manager l- Brunswick Nuclear Project l GMT/gmt

' Enclosure

1. cc: Mr. S . . D. Ebneter i Mr. N.'B. Le

! Mr. R..L. Prevatte )

+

l: 1 l -: i105130109 91041.9 PDR j ADOCK 05000324 l

• PDR .

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SUMMARY

review of motor operated '

Power & Light's (CP&

Letter L) a 10-CFR-21 reportable 89-10, During Carolina valve testing per Generic discrepancy between data obtained (MAC) Systems A

identified.

iscue was our two Motor Actuator Characterization and the BSEP Limitorque utilizing Limitorque Corporation,i n of the accuracy ofThis the actuators.

supplied by theActuator on Test Stand Limitorque led to SMB-00 an investigat there in o evident an performed actuators showed testing by the MAC System and the investigation on SMB-00 Actuator Test Stand.

difference between the torque indicated output torque measured at the BSEP Limitorqueftware diameter. Due to error thisresulting The variation is explained as a possible so xpected to disagree by from the differences in assumed worm-gear f test data dif ference in diameter, the two systems are eThis is supporte about 14%. 1991. In the (several test runs) gathered1991 between January 5, during to January Valvethe program, MAC 20, a difference performed to the conservatism applied and the context of the overall Motor pressure, operatorof required thrust,14%inshould most have

when calculating differential A potential error of 14% will not,ility, However Engin February 15, 1991 i

l required torque range.

(EER)cases, 91-0056produce completed a onUnit concern 1 andfor17valve on Unit operab 2) l

' Evaluation Report and revealed one valve I evaluated each safety-related valve (10 onthat had be had been adjusted on January l with an operability concern. torque setting as j Drain Line Inboard Isolation valve, 8 foot-l 14, 1990 using the MAC System, maximum DP and it of may have afoot-po 1020 psid.

i low as 20.9 evaluated for a realistic t Isolation System (PCIS) l pounds i d to isolate on a l

Therefore, valve this Group 1As Primarya result Containmenmay of this evaluation,was nothung clo break in the MSL Drain Line. (2-3405) isolation valve (2-B21-Feb. 19, 1991 a Caution Tag i B21-F016 F019) valve closed, unless the outboardis LER 2-89-005 on closed l reported by notor software problem was as used for SMB-3 tification l

A similar Corporation's MAC System l

l Limitorque This was reported by Limitorque 3 10-CFR-21 noActuators on O actuators.

' on MAC Software Errors for SMB/SB/SBD-1989.

I i

l N

4 i

4 i

. i d

INITIAL CONDITIONS On April 24, 1991, when this item was determined to be 10CFR21 reportable, Unit 1 and 2 were in Cold Shutdown for Diesel Generator repairs.

EVENT DESCRIPTION 1991 a discrepancy between data obtained In early January, utilizing the Motor Actuator Characterization (MAC) d i of the accuracy of the testing performed on Limitorque SMB-00 actuators.

EVENT INVESTIGATION j The investigation into MAC System accuracy performed between January 5 and January 20 of 1991 SMB-00 noted that theagainst actuator output torque design indicated in operating i

a

as indicated by the MAC System, was higher differential pressure, than that indicated by testing on the BSEP Limitorque Actuator Test j

Stand.

The investigation into the variation revealed that the worm-gear ef fective radius is approximately 0.16 feet versus in radius 0.1827 used would feet used by the MAC System. The difference This is supported by the 4

cause the data to disagree by about 14%.

limited amount of test data (several testSystem The MAC runs) gathered during the may also measure the MAC System Accuracy Testing. result input in torque at losses mechanical the drive in sleeve rathe the This could the actuator.

actuator totaling about 5 foot-pounds not being accounted for in the MAC System software .

91-0056 completed February The Engineering Evaluation Report (EER)1991 determined there are 15, safety related valves thatMAC hadSystems their torque (see valves and 17 Unit 2 using the Limitorque switch settings Itset evaluated each valve and has shown them to be 4

attachment 1). (Main Steam Line Drain Inboard is operable except for the 2-B21-F016This is a PCIS Group 1 Isolation valve that Isolation Valve).above 500 psig except to support maintenance, normally closed

' draining or equalizing activities on the Main Steam Isolation Valves. It has a specified torque switch setting range of 27.9 foot- to 35 foot-pounds.

The as-left torque switch setting was 29.6 pounds, as indicated by the MAC System, but Thethis EERcould be anaactual evaluated torque setting as low as 20.9 foot-pounds. foot-realistic torque required to close the actuator to be 21.8 pounds, which is above the 20.9 foot-pounds that may be available.

Therefore, the valve may not close against 1000 psid asHowever, requiredthe to isolate asetting break in theclose will MaintheSteam Line valve Drain aline.

against DP of up to 966 presentAccordingly, until the torque switch setting can be adjusted psid.

within the allowable range, a Caution Tag (2-3405) has been hung to insure the 2-B21-F016 will not be opened above a conservative value of 850 psig unless the outboard isolation 2-B21-F019 is closed. The i

4 open torque switches of these valves are bypassed by jumpers and so are not at issue.

CORREC1IVE ACTIQld EER 91-0056 evaluated the operability of all SMB-00 Actuators whose(completed torque switches are presently set using the MAC System. -

2/15/91) and established corrective action items to:

1) .

Re-adjust the torque switches of Unit11/31/92. 1 Mos's to comply with the allowable torque ranges by 2). Re-adjust the torque switches of Unit 12/31/91. 2 MOV's to comply with the allowable torque ranges by for the MAC System reportability 3). Evaluate 10CFR21 (Performed by this letter) potential error.

4). Review the MAC System to determine if potential prob by 12/31/91.

Take actions to assure that 2-B21-F016 will not be opened 2-B21-F019 is closed.

5). 850 psig, unless the above (Completed on 2/19/91)

Additionally, thebetwo BSEP MAC Systems will corrected, or further evaluated and not be the MAC System can compensated for (Technical Support Memo 91-204).

Limitorque Corporation has been contacted about the potential software problem.

i

! EVENT ASSESSMENT If tne closing torque switches of SMB-00 actuators were set below the design values using the MAC System, the valves would not fully Failure close under design basis dif ferential pressure conditions.o in conjunction with a single failure of the redundant isolation If this 1

valve,-could result in a breach of primary containment.

containment isolation valve failed to completely close due to a low torque setting, it is possible that the actual valve disk This travel condition may stop below the 4% open limit switch setting. indicating closed on the Con would result in the valve Reactor Turbine Gauge Board (RTGB) even though it would not be fully seated.

Consequently, the fact that the valve did not fully seat may not be detected by Operations.

insure the 2-B21-F016 remains

! With compensatory action taken toshut under conditions where the a adequate, operability of all adjusted valves has been evaluated to f exist.

.',, ,f .

3 ATTACHMENT 1 C

Safety-Related SMB-00 Motor Operatei Valves Set Up Using The MA-System DE9CRIPTION COMPONENT Unit 1 Unit 2 l

Core Spray Pump A Suppression P. ol 1-E21-FOO1A 2-E21-F001A Suction Valve Core Spray Pump B Suppression Pool 1-E21-F001B 2-E21-F001B

! Suction Valve Coolant Injection l 2-E41-F004 High Pressure Storage Tank l

1-E41-F004 -(HPCI) Condensate

Suction Valve HPCI~ Suppression Pool Suction Valve-l 1-E41-F041 2-E41-F041 HPCI Suppression _ Pool Suction Valve 4

1-E41-F042 2-E41-F042 Reactor Coolant Isolation Cooling NA 2-E51-F007 Steam Supply Inboard

, (RCIC)

! -Isolation Valve j RCIC Steam Supply Outboard Isolation

~

NA 2-E51-F008 j Valve RCIC Condensate Storage Tank Suction NA 2-E51-F010 Valve-RCIC Pump Discharge Valve 1-E51-F012 2-E51-F012 RCIC Injection. Valve NA 2-E51-F013 RCIC Suppression Pool Suction Valve 1-E51-F029 2-E51-F029 RCIC Suppression Pool Suction Valve l

1-E51-F031 2-E51-F031 RCIC-Turbine Steam Supply: Valve? to j 2-E51-F045 Residual- Heat Removal .(RHR) 1-E51-F045 1-E11-F049 NA

'Radwaste_ Inboard-Isolation Valve 2-B21-F016 MSL Drain Inboard Isolation Valve NA 2-B21-F019 MSL Drain Outboard Isolation. Valve NA Reactor Water Cleanup (RWCU) Inlet' 2-G31-F001 NA Inboard' Isolation Valve-2-G31-F004 RWCU Inlet Outboard Isolation Valve NA