Information Notice 2019-10, Failures Reported in Eaton/Cutler Hammer A200 and Freedom Series Contactors

Failures Reported in Eaton/Cutler Hammer A200 and Freedom Series Contactors

ML19294A196
Person / Time
Issue date:	12/04/2019
From:	Chris Miller NRC/NRR/DRO
To:
References
IN-19-010
Download: ML19294A196 (5)

ML19294A196

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

OFFICE OF NEW REACTORS

WASHINGTON, DC 20555

December 4, 2019

NRC INFORMATION NOTICE 2019-10: FAILURES REPORTED IN EATON/CUTLER HAMMER

A200 AND FREEDOM SERIES

CONTACT

ORS

ADDRESSEES

All holders of an operating license or construction permit for a nuclear power reactor under Title 10

of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and

Utilization Facilities, except those that have permanently ceased operations and have certified that

fuel has been permanently removed from the reactor vessel.

All holders of and applicants for a combined license under 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants.

PURPOSE

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

addressees of operating experience with regard to failures of Eaton/Cutler Hammer A200 and

Freedom series contactors.

These contactors are widely used throughout the nuclear industry in various applications, many of

which are safety related. Under certain conditions, these contactors may stick closed, preventing

the contactors from performing their safety function. The NRC expects that recipients will review

the information in this IN for applicability to their facilities and consider actions, as appropriate, to

avoid similar problems. INs may not impose new requirements, and nothing in this IN should be

interpreted to require specific action.

DESCRIPTION OF CIRCUMSTANCES

The NRC has received multiple reports1,2 of instances of Eaton/Cutler Hammer contactors sticking

shut when power is removed, as shown in the table below. In addition, while not formally reported

to the NRC, nuclear suppliers have also received information about additional failures.

1 AZZ Nuclear, Part 21 Report No. P21-02082019, Initial Notification of potential 10 CFR Part 21, EATON A200

Series Starters/Contactors, February 8, 2019 (Agencywide Documents Access and Management System

(ADAMS) Accession No. ML19053A499).

2 Curtiss-Wright Corporation/QualTech NP, Notification of 10 CFR Part 21 on Eaton/Cutler Hammer A200 series

Starters (& Contactors), December 18, 2015 (ADAMS Accession No. ML15357A042). Contactor

Type

1. of Installed

Failures

Mfg. Date

Range

Failure

Dates

Plant

Vendor

A200 Series

8

5/2008-12/2012

2008-2015 Diablo Canyon

Curtis Wright

A200 Series

7

2011-2015*

2017-2019 Susquehanna

AZZ/NLI

Freedom Series

6

2016-2017

2018 LaSalle

Westinghouse

• The manufacture date for one of the failed contactors is unknown.

These contactors are commercially manufactured components that have been dedicated for

safety-related use. Many of the A200 series contactors were originally supplied by Westinghouse

and installed in Westinghouse-manufactured motor control centers. Westinghouse and other

third-party suppliers have also supplied Eaton/Cutler Hammer A200 and Freedom series contactors

as replacements for both Westinghouse and non-Westinghouse original equipment.

Recently, failed contactors from LaSalle County Station and Susquehanna Steam Electric Station

were returned to their respective supplying vendors, Westinghouse and AZZ/NLI, for examination.

Both Westinghouse and AZZ/NLI performed root cause evaluations of the failed devices. Through

its commercial relationship with the commercial manufacturer Eaton/Cutler Hammer, Westinghouse

was able to perform an extensive examination of the overall root cause of this issue. Although the

AZZ/NLI root cause analysis was limited to the specific returned components, both evaluations

came to similar conclusions.

In its letter to the NRC dated September 24, 2019, Westinghouse provided a copy of its Nuclear

Safety Advisory Letter (NSAL)-19-2, Revision 0, Contactors Failing to Release/Open When

De-energized, dated August 28, 2019 (ADAMS Accession No. ML19269B709), that it had sent to

all its nuclear-related customers about this issue. The results of the AZZ/NLI evaluation are

summarized in its evaluation under 10 CFR Part 21, Reporting of Defects and Noncompliance, dated August 29, 2019, and, in general, are in agreement with the Westinghouse conclusions.

As multiple suppliers may have provided these contactors to facilities, this IN summarizes the

Westinghouse NSAL and the AZZ/NLI 10 CFR Part 21 report below.

DISCUSSION

Previous failures of A200 series contactors had been attributed to certain materials used in the

manufacturing process and were thought to be limited to certain manufacture date codes.

However, more extensive analysis performed on returned sticking contactors that had manufacture

date codes outside of the range thought to be affected has revealed the existence of an additional

failure mechanism. Consequently, it is now believed that contactors under all manufacture date

codes are potentially susceptible to the failure mechanism as described below.

The failure analysis of the returned contactors by Westinghouse and Eaton/Cutler Hammer

identified a contaminant on the magnet and armature pole faces consistent with the breakdown of

an organic material. The material emanates from the laminations of the contactor core and

armature and is part of the original equipment design. It does not result from any recent design

changes or from the manufacturing process itself. As part of an extent-of-condition review, Westinghouse tested more than 100 Freedom and A200 series contactors of various sizes under

specific temperatures, voltages, and durations to replicate the failure mode. Westinghouse has

confirmed that under the right conditions, the organic-based nonmetallic material can leach out and migrate to the mating surface of the core and armature. Once migration to the pole-face surface

occurs, the material degrades from heat, moisture, and oxygen, and causes the contactors to stick.

Factors that contribute to and accelerate the failure mode include the following:

temperature

-

type of coil installedlow-voltage drop-out coils produce higher temperatures

-

voltage applied to coilhigher voltage drives much higher temperatures

-

environmenthigher ambient temperatures

time

-

energized durationlack of cycling for extended periods of time

The following contactor series showed signs of sticking during the Westinghouse extent-of-condition

testing:

A200, Sizes 1-4

Freedom, Sizes 2-4

While this same material may be used in other Eaton manufactured components such as D15, AR,

and BF Relays, there have been no reports of similar failures and Westinghouse testing has shown

that these components are not susceptible to the previously described failure mechanism.

In its NSAL, Westinghouse indicated that Eaton/Cutler Hammer is planning to change the laminate

coating material used in the manufacture of the commercial contactors. The date the manufacturer

will implement the design change is currently unknown.

Freedom and A200 series contactors, Sizes 1-4, are used in many different safety-related and

non-safety-related applications; however, Westinghouse has determined that this potential failure

mode is limited to components used in continuously energized applications. Operation at high

ambient temperatures or high control voltages, or both, for an extended period increases the

potential for a failure. Components used in momentary applications are not susceptible to this

failure mode. Also, if continuously energized applications have been energized for a cumulative

total of 1 year or more and have been successfully cycled, Westinghouse data suggests they may

no longer be susceptible to this failure mode; however, testing done by AZZ/NLI on one contactor

taken from the Susquehanna Nuclear Station tends to conflict with that conclusion as that contactor

had been energized for over 1 year, had been successfully cycled, and then stuck closed.

For the affected contactors, the safety significance of this issue will vary based upon site-specific

and application-specific conditions. Factors that would impact the safety significance include

whether and how quickly loads are able to be deenergized locally through the manual opening of

the breaker at the motor control center cubicle and whether the specific contactor is relied upon to

open to perform automatic load shedding during certain accident scenarios.

In its NSAL, Westinghouse has recommended the following actions:

Freedom and A200 series continuously energized contactors that have not been cycled

since the original installation should be cycled at the earliest available opportunity. *

Any A200 or Freedom series contactors that fail to open should be replaced with contactors

manufactured with the new material.

Although not in the NSAL specifically, Westinghouse has also recommended in recent webinars

that its customers replace continuously energized contactors that are in critical applications that

have had less than 1 year of cumulative service, regardless of whether or not they fail to open.

Westinghouse has indicated that it is implementing changes to its dedication procedures to ensure

that all subsequently procured contactors are suitable for their safety-related applications and will

be of the new material design.

Related NRC Generic Communications

None

CONTACT

This IN requires no specific action or written response. Please direct any questions about this

matter to the technical contact listed below.

/RA/

Christopher Miller

Division of Reactor Oversight

Office of Nuclear Reactor Regulation

Technical Contacts:

Jeffrey Jacobson, NRR/DRO

301-415-2977 E-mail: jeffrey.jacobson@nrc.gov

Kerri Kavanagh, NRR/DRO

301-415-3743 E-mail: kerri.kavanagh@nrc.gov

Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under NRC Library, Document Collections.

ML19294A196

OFFICE

NRR/DRO/IQVB

QTE

NRR/DRO/IQVB/BC

NRR/DRO/IOEB/PM

NAME

JJacobson

JDougherty

PPrescott for

KKavanagh

BBenney

DATE

11/12/19

10/23/19

11/13/19

11/21/19 OFFICE

NRR/DRO/IOEB/LA

NRR/DRO/IOEB/BC

NRR/DRO/D

NAME

IBetts

LRegner

CMiller

DATE

11/25/19

11/27/19

12/4/19