Information Notice 1989-86, Type Hk Circuit Breakers Missing Close Latch Anti-Shock Springs

Type Hk Circuit Breakers Missing Close Latch Anti-Shock Springs

ML031190035
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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	12/15/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-086, NUDOCS 8912110174
Download: ML031190035 (3)

a. -

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 December 15, 1989 NRC INFORMATION NOTICE NO. 89-86: TYPE HK CIRCUIT BREAKERS MISSING

CLOSE LATCH ANTI-SHOCK SPRINGS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

Information Notice No. 87-41, Failures of Certain Brown Boveri Electric

Circuit Breakers" (IN 87-41) was issued August 31, 1987. This information

notice is intended to alert addressees of additional information regarding

Type HK circuit breakers that may have been manufactured without a close

latch anti-shock spring. 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 do not constitute NRC requirements; therefore, no specific action or written response is required. -

Background:

Type HK circuit breakers utilize a charging spring motor to charge-(compress)

the charging springs. At the end of the charging cycle, a close latch is

engaged to hold the charging springs in the charged (compressed) position.

The circuit breaker can then be closed (by spring force) on demand.

IN 87-41 highlighted instances at Limerick Unit 1 and Beaver Valley Unit 2 where Type HK circuit breakers inadvertently closed following completion of

the charging cycle. Subsequent to the occurrence at Limerick Unit 1, the

manufacturer indicated that this condition can be corrected by adding an

anti-shock spring to the close latch. The manufacturer also indicated that

this anti-shock spring was not included in Type HK circuit breakers manu- factured prior to 1973 and from June 1975 to June 1977.

Description of Circumstances

-

During the recent refueling outage at Fermi Unit 2, the licensee inspected

both safety-related and non-safety-related Type HK circuit breakers. The

close latch anti-shock springs were observed to be missing in approximately

40 safety-related Type HK circuit breakers that had been manufactured outside

of the previously identified timeframes. (The identified circuit breakers

8912110174

U v U

IN 89-86 December 15, 1989 were manufactured in 1974.) Thus, the timeframes previously identified by the

manufacturer (prior to 1973 and from June 1975 to June 1977) may not be totally

inclusive. In addition, because of changes in corporate name, mergers, etc.,

Type HK circuit breakers may indicate manufacture by ITE, ITE Imperial, Gould, Brown Boveri, or a combination thereof. The current name of the manufacturer

is ASEA Brown Boveri. Recipients may need to be cognizant of this when

determining whether they utilize potentially affected equipment.

Discussion of Safety Significance:

Failure to close on demand or inadvertent closure of a Type HK circuit breaker

could result in a circuit breaker not performing its intended function. This, in turn, could result in the loss of a power supply. For example, inadvertent

closure of a Type HK circuit breaker onto a vital bus supplied by an emergency

diesel generator, such as during load sequencing, could result in overloading

the emergency diesel generator. This could occur at the end of a spring charging

cycle on a Type HK circuit breaker which was tripped by a loss-of-offsite power

signal, as typically happens Just prior to load sequencing.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate NRR project manager.

Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Jack Ramsey, NRR

(301) 492-1167 Attachment: List of Recently Issued NRC Information Notices

D '-'A

Attachment

IN 89-86 December 15, 1989 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date ot

Notice No. Subject Issuance Issued to

89-85 EPA's Interim Final Rule 12/15/1 B9 All medical, academic, on Medical Waste Tracking industrial, waste

and Management broker, and waste

disposal site licensees.

89-84 Failure of Ingersoll Rand 12/12/lB9 All holders of OLs

Air Start Motors as a Result or CPs for nuclear

of Pinion Gear Assembly power reactors.

Fitting Problems

89-83 Sustained Degraded Voltage 12/11/l89 All holders of OLs

on the Offsite Electrical or CPs for nuclear

Grid and Loss of Other power reactors.

Generating Stations as

a Result of a Plant Trip

89-82 Recent Safety-Related 12/7/8 9 All NRC licensees

Incidents at Large authorized to

Irradiators possess and use

sealed sources at

large irradiators.

89-59, Suppliers of Potentially 12/6/8 9 All holders of OLs

Supp. 1 Misrepresented Fasteners or CPs for nuclear

power reactors.

89-81 Inadequate Control of 12/6/8 9 All holders of OLs

Temporary Modifications or CPs for nuclear

to Safety-Related Systems power reactors.

89-80 Potential for Water Hammer, 12/1/8 19 All holders of OLs

Thermal Stratification, and or CPs for nuclear

Steam Binding in High- power reactors.

Pressure Coolant Injection

Piping

89-79 Degraded Coatings and 12/1/839 All holders of OLs

Corrosion of Steel or CPs for LWRs.

Containment Vessels

OL - Operating License

CP = Construction Permit