Information Notice 1985-82, Diesel Generator Differential Protection Relay Not Seismically Qualified

Diesel Generator Differential Protection Relay Not Seismically Qualified

ML031180302
Person / Time
Site:	Beaver Valley, Millstone, Hatch, 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, 05000262, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	10/18/1985
From:	Jordan E NRC/IE
To:
References
IN-85-082, NUDOCS 8510150080
Download: ML031180302 (4)

SSINS No.: 6835 IN 85-82 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 October 18, 1985 IE INFORMATION NOTICE NO. 85-82: DIESEL GENERATOR DIFFERENTIAL PROTECTION

RELAY NOT SEISMICALLY QUALIFIED

Addressees

All nuclear power reacto4'-facilities holding an operating license (OL) or a

construction permit (CP).

Purpose

This information notice is provided to alert licensees of a potentially signif- icant safety problem involving a General Electric (GE) Model 12CFD relay that

is not seismically qualified for Class IE service when in the de-energized

state of operation. The relay is used for protection of an emergency diesel

generator (EDG) against phase-to-phase or phase-to-ground electrical faults

(shorts) by both boiling water reactor (BWR) and pressurized water reactor

(PWR) nuclear power generating stations.

It is suggested that recipients review this information for applicability to

their facilities and consider actions, if appropriate, to preclude similar

problems occurring at their facilities. However, suggestions contained in this

information notice do not constitute NRC requirements; therefore, no specific

action or written response is required.

Description of Circumstances

Licensees of BWR and PWR nuclear generating stations have reported using a

high-speed differential protection relay that has been declared by the manufac- turer to be not seismically qualified for the service intended. The relay, GE

Model 12CFD, which is being used for emergency diesel generator protection

against electrical shorts and grounds at the generator output, has not been

seismically qualified to operate in the de-energized state for this applica- tion. Generally, the relay operates in the de-energized position before EDG

operation. However, it then operates in the energized position whenever the

EDG provides an electrical output to essential Class IE components. The safety

concern of this issue involves an inadvertent activation of the normally

de-energized relay from a seismic event. Momentary activation of the relay, in the circuits examined, blocks the automatic start feature of the EDG during

certain emergency plant conditions through operation of another relay in the

system.

8510150080

IN 85-82 October 18, 1985 On June 17, 1985, Kewaunee Nuclear Power Generating Station notified the NRC

that the high-speed differential relay being used for diesel generator protec- tion at their plant did not meet the seismic requirements for that application

when the relay was in the de-energized mode. Kewaunee had discovered that the

relay, GE 12CFD series, had earlier failed to meet seismic requirements under

similar circumstances at the Arkansas Unit 1 Nuclear Generating Station in

November 1981. The short term corrective measure taken by Kewaunee to resolve

the issue was to defeat the relay trip function. The long term corrective

measures are currently under review.

At Palisades, while finalizing the environmental qualification plan for the

diesel generator control panel, the licensee discovered that the GE high-speed

differential relays specified by design drawings would not meet the seismic

requirements for the service intended at that plant when the relay was in the

de-energized mode. The relay was identified as GE Model 12CFD and was being

used in an application similar to that at the Kewaunee plant above. The

licensee of Palisades has since replaced all deficient relays with relays

seismically qualified for service in all modes of operation.

Background:

An event occurred at Arkansas Unit 1 plant on November 19, 1981, when the plant

was operating at 90% of full power. An alarm sounded alerting operations

personnel that the generator lockout relay, associated with the plant's No. 1 EDG, had tripped. The licensee's investigation of this occurrence revealed

that the "C" phase differential relay (one relay is used for each phase of the

three-phase system) had activated and caused a generator lockout relay to trip

even though the affected EDG was not operating at the time. A walk through by

persons in the EDG area revealed that the EDG exiter cubicle, which houses the

differential relays, may have been opened and reclosed with sufficient force to

cause spurious operation of the differential relay, GE Model 12CFD. Subsequent

investigation by the licensee concluded that the relay did not meet the minimum

seismic qualifications in that plant's design when the EDG is in the standby

mode and the relay is in a de-energized state. A similar problem was identi- fied with the same make and model differential relays at both Brunswick Unit 2 and at Salem Unit 1 in early 1982.

Arkansas Unit 1, Brunswick Unit 2, and Salem Unit 1 have since replaced the

deficient relays with a relay that GE considers more suitable and seismically

qualified for the application discussed above.

The NRC review of the above problems concluded that the relays should be

seismically qualified in their energized and de-energized states to preclude

their spurious activation during a seismic event. Additionally, review of GE's

GER 3069 report, "Relay Protection of Class IE Systems," shows that the 12CFD

differential relays were successfully tested for 3.5 g in the energized modes

and only 0.75 g in the de-energized mode. The calculated required g-level

capacity, including the effects of floor response, for this equipment at

IN 85-82 October 18, 1985 Arkansas Unit 1 exceeded the qualified g level of the 12CFD relay in the

de-energized mode by a factor of about three. Review of GE's GER 3069 report

also revealed that GE type IJD differential relays do meet seismic requirements

in all modes of operation mentioned above and is the GE recommendation for

replacement of the differential relay in question.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate regional office or this office.

rr n ,Director

Divisi of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Vincent D. Thomas

301-492-4755 Attachment: List of Recently Issued IE Information Notices

.. . .

Attachment 1 IN 85-82 October 18, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information . Date of  :

Notice No. Subject Issue Issued to . .

85-81 Problems Resulting In 10/17/85 All power reactor l

Erroneously High Reading facilities holding

With Panasonic 800 Series an OL or CP and

Thermoluminescent Dosimeters certain material

and fuel cycle

licensees

85-80 Timely Declaration Of An 10/15/85 All power reactor

Emergency. Class Implementa- facilities holding

tion Of An Emergency Plan, an OL or CP

And Emergency Notifications

85-17 Possible Sticking Of ASCO 10/1/85 All power reactor.

Sup. 1 Solenoid Valves facilities holding

an OL or CP

85-79 Inadequate Communications 9/30/85 All power reactor

Between Maintenance, facilities holding

Operations, And Security an OL or CP; research

Personnel and nonpower reactor

facilities; fuel

fabrication and

processing facilities

85-78 Event Notification 9/23/85 All power reactor

facilities holding

an OL or CP

85-77 Possible Loss Of Emergency 9/20/85 All power reactor

Notification System Due To facilities holding

Loss Of AC Power an OL or CP

85-76 Recent Water Hammer Events 9/19/85 All power reactor

.,

facilities holding 1.

an OL or CP

85-75 Improperly Installed Instru- 8/30/85 All power reactor

mentation, Inadequate Quality facilities holding

Control And Inadequate Post- an OL or CP

modification Testing

OL = Operating License

CP = Construction Permit