Information Notice 1992-45, Incorrect Relay Used in Emergency Diesel Generator Output Breaker Control Circuitry

Incorrect Relay Used in Emergency Diesel Generator Output Breaker Control Circuitry

ML031200213
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	06/22/1992
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-92-045, NUDOCS 9206160071
Download: ML031200213 (9)

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 June 22, 1992 NRC INFORMATION NOTICE 92-45: INCORRECT RELAY USED IN EMERGENCY DIESEL

GENERATOR OUTPUT BREAKER CONTROL CIRCUITRY

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

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

notice to alert addressees to a potential problem that may exist at their

facilities resulting from the failure of a relay in the control circuitry for

an emergency diesel generator (EDG) output breaker to perform its intended

design function. 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 April 3, 1992, during the weekly idle start test of an EDG at the St. Lucie

Plant, Unit 1, of the Florida Power and Light Company (the licensee), the

control room operator was unable to close the output circuit breaker after the

EDG had started, warmed up, and achieved rated speed. The licensee analyzed

the control circuitry and found that a relay was not functioning properly for

an unknown reason. The licensee sent the relay to Westinghouse for failure

analysis. This relay is intended to prevent the output circuit breaker from

closing when the generator is operating at a frequency below 54 Hz. However, the licensee found independent of the specific cause of the failure which

occurred on April 3, 1992, that the relay had not been properly selected and

was not able to perform its intended function. When operating as actually

designed, the relay would permit the circuit breaker to close at all frequen- cies up to 62.5Hz. The licensee had not noticed this discrepancy during

previous testing because the EDG usually achieves 90 percent of full voltage

(the circuitry also includes an under-voltage permissive relay function) at

almost the same time as it achieves 90 percent of full frequency. The

licensee determined that the relay had been incorrectly selected because of an

ambiguity in the Westinghouse catalog description for this particular relay

(Style 177C717G03, 60 Hz/120 V). Westinghouse has since corrected the catalog

description. The licensee corrected the error in relay selection by replacing

the relay with another relay that properly performs the under-frequency

permissive function.

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IN 92-45 June 22, 1992 Discussion

The EDG control circuitry is designed to prevent the output circuit breaker

from closing prematurely. This circuitry includes under-frequency and under- voltage permissive relays to ensure that the EDG attains both 90 percent of

rated frequency and 90 percent of rated voltage before the output circuit

breaker closes. Under emergency conditions (e.g., accident conditions with

loss of offsite power), use of the incorrect relay could allow the output

circuit breaker to close before the EDG reaches the necessary operating

conditions possibly resulting in shutdown of the diesel engine and/or damage

to the safety-related loads.

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

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

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Charles E. Rossi, Dire r

___Di-vision-of OperationalEvents Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Walter P. Haass, NRR

(301) 504-3219 E. Nick Fields, NRR

(301) 504-1173 Attachment: List of Recently Issued NRC Information Notices

K>J

Attachment

IN 92-45 June 22, 1992 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

92-44 Problems with Westing- 06/18/92 All holders of OLs or CPs

house DS-206 and DSL-206 for nuclear power reactors.

Type Circuit Breakers

92-43 Defective Molded Phen- 06/09/92 Al 1 holders of OLs or CPs

olic Armature Carriers for nuclear power reactors.

Found on Elmwood Con- tactors

92-42 Fraudulent Bolts in 06/01/92 All holders of OLs or CPs

Seismically Designed for nuclear power reactors.

Walls

92-41 Consideration of the 05/29/92 All holders of OLs or CPs

Stem Rejection Load in for nuclear power reactors.

Calculation of Required

Valve Thrust

92-40 Inadequate Testing of 05/27/92 All holders of OLs or CPs

Emergency Bus Under- for nuclear power reactors.

voltage Logic Circuitry

92-39 Unplanned Return to 05/13/92 All holders of OLs or CPs

Criticality during for nuclear power reactors.

Reactor Shutdown

92-38 Implementation Date for 05/12/92 All holders of OLs or CPs

the Revision to the EPA for nuclear power reactors, Manual of Protective non-power reactors and

Action Guides and Pro- materials licensees auth- tective Actions for orized to possess large

Nuclear Incidents quantities of radioactive

material.

92-37 Implementation of the 05/08/92 All Nuclear Regulatory

Deliberate Misconduct Rule Commission Materials

Licensees.

OL = Operating License

CP = Construction Permit

IN 92-45 June 22, 1992 Discussion

The EDG control circuitry is designed to prevent the output circuit breaker

from closing prematurely. This circuitry includes under-frequency and under- voltage permissive relays to ensure that the EDG attains both 90 percent of

rated frequency and 90 percent of rated voltage before the output circuit

breaker closes. Under emergency conditions (e.g., accident conditions with

loss of offsite power), use of the incorrect relay could allow the output

circuit breaker to close before the EDG reaches the necessary operating

conditions possibly resulting in shutdown of the diesel engine and/or damage

to the safety-related loads.

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

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

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Walter P. Haass, NRR

(301) 504-3219 E. Nick Fields, NRR

(301) 504-1173 Attachment: List of Recently Issued NRC Information Notices

VIB/DRIS OEAB/NRR RIII VIB/DRIS VIB/DRIS VIB/DRIS

WPHaass* ENFields* KLandis** GCwalina* LNorrholm* BKGrimes

04/15/92 04/15/92 04/13/92 04/15/92 04/21/92 04/23/92 OEAB/NRR OGCB/NRR DO "Y

AChaffee* CBerlinger**CRossi Tch. Edtr.*

04/29/92 05/20/92 06//1/92 04/15/92 DOCUMENT NAME: 92-45.in

• • Telephone concurrence received on 4/13/92

• • See previous concurrence.

IN 92-XX

K> June XX, 1992 ambiguity in the Westinghouse catalog description for this particular relay

(Style 177C717G03, 60 Hz/120 V). Westinghouse has since corrected the catalog

description. The licensee corrected the error in relay selection by replacing

the relay with another relay that properly performs the under-frequency

permissive function.

Discussion

The EDG control circuitry is designed to prevent the output circuit breaker

from closing prematurely. This circuitry includes under-frequency and under- voltage permissive relays to ensure that the EDG attains both 90 percent of

rated frequency and 90 percent of rated voltage before the output circuit

breaker closes. Under emergency conditions (e.g., accident conditions with

loss of offsite power), use of the incorrect relay could allow the output

circuit breaker to close before the EDG reaches the necessary operating

conditions within the 10-second required period possibly resulting in shutdown

of the diesel engine and/or damage to the safety related loads.

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 contacts listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Sincerely, Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Walter P. Haass, NRR

301-504-3219 E. Nick Fields, NRR

301-504-1173 Attachment: List of Recently Issued NRC Information Notices

OFF VIB/DRIS OEAB/NRR R III VIB/DRIS VIB/DRIS VIB/DRIS

NAME WPHaass* ENFields* Iqandis** GCwalina* f lNorrholm* BKGrimes*

DATE 04/15/92 04/15/92 04/13/92 04/15/92 04/21/92 04/23/92 OFF 0EAB/NRR OGCB/NMR DOEA/NRR

NAME AChaffee* CBerlinqfer CRossi CO Tch. Edtr.*

DATE 04/29/92 05/ /92 05/ /92 04/15/92 OFFICIAL RECORD COPY DOCUMENT NAME: INF0N0TE.WH

• • Telephone Concurrence received on 4/13/92

• • See Previous Concurrence

DISTRIBUTION:

VIB R/F DRIS R/F INorrholm WPHaass

AChaffee BKGrimes ENFields CBerlinger

KLandis CRossi GCwalina

K)> IN 92-XX

K> May -, 1992 Discussion

The EDG control circuitry is designed to prevent the output circuit breaker

from closing prematurely. This circuitry includes under-frequency and under- voltage permissive relays to ensure that the EDG attains both 90 percent of

rated frequency and 90 percent of rated voltage before the circuit breaker

closes. Under emergency conditions (e.g., accident conditions with loss of

offsite power), use of the incorrect relay could allow the output circuit

breaker to close before the EDG reaches the necessary operating conditions

within the 10-second required period.

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.

Sincerely, Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Walter P. Haass, NRR

301-504-3219 E. Nick Fields, NRR

301-504-1173 Attachment: List of Recently Issued NRC Information Notices

Distribution:

VIB R/F WNorrholm

DRIS R/F BKGrimes

WPHaass AChaffee

ENFields CBerlinger

KLandis CRossi

GCwalina

Concurrence:

OFF VIB/DRIS OEAB/NRR R III VIB/DRIS VIB/DRIS VIB/DRIS

NAME WPHaass* ENFields* KLandis** GCwalina* T-Norrholn* BKGrines*

DATE 04/15/92 04/15/92 04/13/92 I 04/15/92 04/21/92 04/23/92 OFF OEAB/NRR OGCB/}m DOEA/NRR

NAME AChaffee* CBer& CRossirjV jTch. Edtr.*

DATE 04/29/92 05i9V/92 05/ /92 04/15/92 I

OFFICIAL RECORD COPY DOCUMENT NAME: INFONOTE.WH

• • Telephone Concurrence received on 4/13/92

• • See Previous Concurrence

IN 92-XX

April XX, 1992 DRISTRIBUTION

VIB R/F

DRIS R/F

WHaass

ENFields

KLandis

GCwalina

LNorrholm

AChaffee

CBerlinger

CRossi

[OFC

NAME

OEAB/NRR

AChafee

OGCB/NRR

CBerlinger

DOEA/NRR

CRossi TechEditor*

D 04L21/92 04/ /92 04/ /92 04/15/92 OFFICIAL RECORD COPY DOCUMENT NAME: A:\INFONOTE.2

• • Telephone concurrence received on 4/13/92

• SEE PREVIOUS CONCURRENCE

K>

IN 92-XX

Apri LXX, 1992 Page{-of 2 DRISTRIBUTION

VIB R/F

DRIS R/F

WHaass

ENFields

KLandis

GCwalina

LNorrholm

AChaffee

CBerlinger

CRossi

concurrence:

/

OFC VIB/DRIS OEAB/NRR RIII VIB/DRIS VIB/RIS VIB/DRIS

NAME WHaass* ENF, ields* KLandis** GCwalina* L BGrimes

DATE 04/15/92 O/15/92 04/13/92 04/15/92 04/-Z,(/92 04/ /92 OFC OEAB/NRR /OGCB/NRR DOEA/NRR

NAME AChaffee / CBerlinger CRossi TechEditor*

DATE 04/ /92/ 04/ /92 04/ /92 04/15/92 OFFI IAL RECORD COPY DOCUMENT NAME: A:\INFONOTE.2

• • Telephope concurrence received on 4/13/92

• SEE PREVTOUS CONCURRENCE

IN 92-XX

April 15, 1992 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.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Walter P. Haass, NRR

301-504-3219 E. Nick Fields, NRR

301-504-1173 Attachment: List of Recently Issued NRC Information Notices

Concurrence:

EOFC

NAME " rX ENFields ad LNorrholm BGrimes

DAE 0 592 04112 4//92 04//~9 04/ /9

04/ /92 IA _ _ _ _ _ _ _ _ _ _ _

NAME AChaffee CBerlinger CRossi

DATE 04/ /92 04/ /92 04/ /92

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