Part 21 Report - 1997-572

 
 

ACCESSION #: 9709230255



                                        NSD-NRC-97-5330



Westinghouse          Energy Systems    Nuclear Services Division

Electric Corporation

                                        Box 355

                                        Pittsburgh Pennsylvania

                                        15230-0355



                                        September 18, 1997



U.S.  Nuclear Regulatory Commission

ATTN: Document Control Desk

Washington, DC 20555-0001



ATTN: NRC Operations Center



Subject:  Follow-up to Notification of the Potential Existence of Defects

          Pursuant to 10CFR 21.21



Westinghouse provided a Notification of the Potential Existence of

Defects Pursuant to 10CFR 21.21 regarding HMCP (Motor Circuit Protectors)

molded case circuit breakers on August 19, 1997 via NSD-NRC-97-5267.

Attached, with the original notification is a Nuclear Safety Advisory

Letter (NSAL-97-007, dated 9/17/97) which transmitted recommendations

regarding this issue to potentially impacted plans.  The plants are

identified in the NSAL.



If you have any questions regarding this information, please call me at

412/374-5292.



Sincerely,



H.  A.  Sepp, Manager

Regulatory and Licensing Engineering



/p



Attachment



"The mission of NSD is to provide our customers with people,

equipment and services that set the standards of excellence in the

nuclear industry."



2536C-RBM-1:091897



Westinghouse        NUCLEAR SAFETY ADVISORY LETTER

Energy Systems

Business

Unit



THIS IS A NOTIFICATION OF A RECENTLY IDENTIFIED POTENTIAL SAFETY ISSUE

PERTAINING TO BASIC COMPONENTS SUPPLIED BY WESTINGHOUSE.  THIS

INFORMATION IS BEING PROVIDED TO YOU SO THAT A REVIEW OF THIS ISSUE

CAN

BE CONDUCTED BY YOU TO DETERMINE IF ANY ACTION IS REQUIRED.



                                  P.O. Box 355, Pittsburgh, PA 15230-0355



Subject: Breaker Trip Settings                        Number: NSAL-97-007

Basic Component: HMCP Molded Case Circuit Breakers    Date: 9/17/97

Plants: See Sheet 3



Substantial Safety Hazard of Failure to Comply Pursuant to 10 CFR

21.21(a)                                               Yes [x] No [ ]

Transfer of Information Pursuant to 10 CFR 21.21(b)    Yes [ ]

Advisory Information Pursuant to 10 CFR 21.21(d)(2)    Yes [ ]



Reference: NSD-NRC-97-5267, 8/19/97



SUMMARY



Three HMCP (Motor Circuit Protectors) molded case circuit breakers were

returned when a utility determined that some of the poles were tripping

outside the specified range.  The settings had been verified through a

commercial dedication process.  This issue was reported to the NRC

pursuant to 10 CFR Part 21 (copy attached).  Recommendations for on-site

testing are provided.



Additional information, if required, may be obtained from the originator.

Telephone 412-374-5953.



Originator(s):

          R.  B.  Miller                H.  A.  Sepp, Manager

          Regulatory & Licensing        Regulatory & Licensing

           Engineering                   Engineering



1810A/NSAL-97-00                                             Sheet 1 of 3



ISSUE DESCRIPTION



Three HMCP (Motor Circuit Protectors) molded case circuit breakers were

recently returned to Westinghouse's vendor, Cutler-Hammer when the

utility determined that some of the poles were tripping outside the

setpoint calibration range.  These breakers were verified to be within

specification before shipment as part of the Westinghouse commercial

dedication process, but two tested out of specification before

installation at the plant and one tripped in service when the motor was

started.  All were found with at least one pole out of specification when

returned.



TECHNICAL EVALUATION



HMCP Series C breakers, through magnetic trip action, provide

instantaneous short circuit protection for motor circuits.  These

breakers have ratings from 3 amps to 600 amps in three frame sizes, The

three breakers returned were all 400 amp, but there is no evidence that

limits the issues to this, size breaker.  The breakers am tested at the

lowest setting and the highest setting as part of the commercial

dedication process.  Intermediate settings are not tested during the

commercial dedication process.  The returned breakers were verified to be

out of specification at the low and high setting positions.  Although

many utilities will perform a verification test before installation,

Westinghouse has not included this as part of maintenance

recommendations.



ASSESSMENT OF SAFETY SIGNIFICANCE



The setpoint on a HMCP breaker is selected to provide circuit protection

without tripping on motor starting current.  Several trip ranges are

available for selection on each breaker.  If the setpoint is not within

the selected range, the possibility exists that the circuit will open

preventing a safety-related motor from starting.  Westinghouse determined

that this issue could potentially create a substantial safety hazard and

therefore reported it under 10 CFR Part 21, Confidence in continued

system performance can be established by a history of successful motor

start tests even if the breaker was not tested at the plant prior to

installation.



RECOMMENDED ACTIONS



Westinghouse recommends that the setpoint selected on the HMCP breakers

be verified prior to installation in addition to periodic surveillance

testing.  Each pole should be tested separately.  It is not recommended

that the breakers be tested with all poles in series since all pole trip

actuators would be exerting a force on the trip bar at the same time,

which could result in tripping at a lower current.



1810A/NSAL-97-00                                             Sheet 2 of 3



                       POTENTIALLY AFFECTED PLANTS



H.  B.  Robinson Unit 2

Shearon Harris

Haddam Neck

McGuire Units 1 & 2

Catawba Units 1 & 2

Turkey Point Unit 3

Wolf Creek

Callaway

Point Beach Unit 1

Yonggwang Units 1 & 2

Maanshan Units 1 & 2

Crystal River Unit 3

Three Mile Island Unit 1

Chinshan Units 1 & 2

Brunswick Units 1 & 2

Peach Bottom Units 2 & 3

Vermont Yankee

Kuosheng Unit 2

Laguna Verde Units 1 & 2



1810A/NSAL-97-00                                             Sheet 3 of 3



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