Information Notice 1997-53, Circuit Breakers Left Racked Out in Non-Seismically Qualified Positions

Circuit Breakers Left Racked Out in Non-Seismically Qualified Positions

ML031050268
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, 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, Crane
Issue date:	07/18/1997
From:	Slosson M Office of Nuclear Reactor Regulation
To:
References
IN-97-053, NUDOCS 9707150258
Download: ML031050268 (8)

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001

July 18, 1997

NRC INFORMATION NOTICE 97-53:

CIRCUIT BREAKERS LEFT RACKED OUT IN NON-

Addressees

All holders of operating licenses or construction permits for nuclear power reactors.

Puroose

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

addressees to the potential that some safety-related circuit breakers in their "racked-out"

positions may not be seismically qualified. 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

requirements; therefore, no specific action or written response is required.

Description of Circumstances

On June 13, 1991, during an in-house electrical distribution system functional inspection, Entergy Operations, Incorporated, the licensee for Arkansas Nuclear One, Unit 2, discovered

that four circuit breakers in the 4160-volt engineered safety features switchgear had been

routinely positioned in a racked-out configuration and seismic qualification for these circuit

breakers in this position was never performed. This problem was reported to the NRC by the

licensee for Arkansas Nuclear One, in accordance with Section 50.72, "Immediate Notification

Requirements for Operating Nuclear Power Reactors," of Title 10 of the Code of Federal

Regulations (10 CFR 50.72), in Event Number21189. On February 10, 1992, the

licensee for Turkey Point, Units 3 and 4, reported in EN 22774 that its 4160-volt circuit

breakers were not seismically qualified in the racked-out position. Recently, licensees have

submitted a number of 50.72 reports on this issue: Susquehanna Steam Electric Company

(EN 31279); Comanche Peak Steam Electric Station (EN 31322); Three Mile Island Nuclear

Station (EN 31323); South Texas Project (EN 31362); Oyster Creek Power Plant

(EN 31325); Millstone Nuclear Power Station, Units 1, 2, and 3 (EN 31335, EN 31336, and, EN 31339); LaSalle County Station (EN 31780); Braidwood Station (EN 31799);

Joseph M. Farley Nuclear Plant (EN 31807 and EN 31967); Clinton Power Station

(EN 31873); and Grand Gulf Nuclear Station (EN 32003).

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IN 97-53

July 18, 1997 Discussion

With breakers in any position other than the seismically qualified racked-in position, the Class 1 E switchgear might not function as required for a design-basis earthquake.

Therefore, the plant is in a condition outside of its design basis.

The root cause of these events was attributed to a lack of understanding of the interaction

between the seismic qualification status of equipment and actual functional andlor operational

configurations of equipment in the plant. When the switchgear was seismically qualified, it

was not understood that the switchgear would be operated with the circuit breakers in the

racked-out position. Also, the seismically qualified circuit breaker positions were not

incorporated into plant operating procedures.

The term "racked-out" was defined to include any breaker position other than the fully

connected operating position. There are several intermediate positions, depending upon the

make and model of the switchgear, such as the "test" position in which the primary contacts

are disengaged but the secondary contacts are in place so that the breaker can be tested.

The "disconnect" position has both the primary and secondary contacts disengaged but the

breaker is still in the switchgear cabinet and, in some cases, restrained. The "removed"

position is similar to the "disconnect" position but the breaker is not restrained. These

intermediate positions may not be seismically qualified.

Because there are so many different makes and models of switchgear, a single generic

resolution of this concern is not likely. The licensees' corrective actions following these

events included restoring the affected breakers to "racked-in" positions; evaluating the

acceptability of various breaker configurations for maintaining seismic qualification, modifying

the switchgear, and seismically qualifying the circuit breakers in all other positions, if needed;

reviewing seismic qualification procedures used to procure new or replacement equipment to

ensure that all anticipated modes of operation are considered; verifying that other similar

equipment is qualified for all operating modes; developing training to enhance general

awareness of the effect that plant operating conditions and equipment status have on the

seismic qualification of the equipment; and physically removing those breakers from the

affected switchgear rooms. It should be noted that removal of the circuit breaker from the

switchgear will result in mass redistribution of the switchgear. Mass redistribution of the

switchgear may then change the frequency of the switchgear and Ks dynamic response

during a seismic event and may invalidate the original seismic qualification of the switchgear.

Therefore, the situation must be evaluated to ensure that the removal of the circuit breaker

will not invalidate the original seismic qualification of the switchgear.

IN 97-53 July 18, 1997 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 Office of Nuclear Reactor Regulation (NRR) project manager.

Mary ee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contact: Y. C. Li, NRR

30 -4 15-2772 E-mail: ycl@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 97-53

July 18, 1997 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

97-52

Inadvertent Loss of

Capability for Emer- gency Core Cooling

System Motorst

07/17/97

All holders of OLs or CPs

for nuclear power reactors

91-50,

Supp. 1

97-51

Water Hammer Events

Since 1991

Problems Experienced

with Loading and

Unloading Spent Nuclear

Fuel Storage and Trans- portation Casks

07/17/97

07/11/97

All holders of OLs or CPs

for nuclear power reactors

All holders of OLs or CPs

for nuclear power reactors

Designers and fabricators

of independent spent fuel

storage installations

All holders of or applicants

for licenses to operate ISFSls

97-50

97-49

97-48

97-47

Contaminated Lead

Products

B&W Once-Through Steam

Generator Tube Inspection

Findings

Inadequate or Inappro- priate Interim Fire

Protection Compensatory

Measures

Inadequate Puncture

Tests for Type B

Packages Under 10 CFR

71.73(c)(3)

07/10/97

07/10/97

07/09/97

06/27/97

All U.S. Nuclear Regulatory

Commission licensees

All holders of OLs or CPs

for nuclear power reactors

All holders of OLs or CPs

for nuclear power reactors

All "users and fabricators"

of type B transportation

packages [as defined in

10 CFR 171.16(10)(B)J

OL = Operating License

CP = Construction Permit

IN 97-53 July 18, 1997 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 Office of Nuclear Reactor Regulation (NRR) project manager.

original signed by S.H. Weiss for

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contact: Y. C. Li, NRR

301-415-2772 E-mail: ycl@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

Tech Editor has reviewed and concurred on 6/3/97 OFC

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IN 97-XX

July XX, 1997 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 Office of Nuclear Reactor Regulation (NRR) project manager.

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contact: Y. C. Li, NRR

301-415-2772 E-mail: ycl@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

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questions about the information in this notice, please contact the technical contact listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contact:

Y. C. Li, NRR

301-415-2772 E-mail: ycl@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

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June XX, 1997 In summary, the event was of concern because it could have resulted in operating conditio

that are outside the plant's design basis.

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

questions about the information in this notice, please contact the technical cont

listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project

anager.

Marylee M. Slosson, ing Director

Division of Reactor rogram Management

Office of Nuclear eactor Regulation

Technical contact: Y. C. Li, NRR

301-415-2772 E-mail: ycl@nrc.gov

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