Information Notice 1993-99, Undervoltage Relay & Thermal Overload Setpoint Problems

Undervoltage Relay & Thermal Overload Setpoint Problems

ML031060586
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:	12/21/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-099, NUDOCS 9312150073
Download: ML031060586 (12)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 December 21, 1993 NRC INFORMATION NOTICE 93-99: UNDERVOLTAGE RELAY AND THERMAL OVERLOAD

SETPOINT PROBLEMS

Addressees

All holders of operating licenses or construction permits for nuclear power

plants.

Purpose

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

notice to alert addressees to continuing discoveries of undervoltage relay and

thermal overload setpoints that are set too low. 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.

Background

In August 1976, the NRC wrote generic letters to all LWR licensees regarding

the need for licensees to evaluate any generic implications of several events

at the Millstone site involving episodes of sustained degraded grid voltage.

On June 2, 1977, as part of multiplant action MPA-23, the staff stated its

position that all licensees must have a second level of undervoltage

protection with a time delay. (During degraded grid voltage episodes, undervoltage relays and thermal overload protective relays protect the safety

equipment.) In a generic letter dated August 8, 1979, the NRC requested all

licensees to determine the capability of the offsite power system to operate

all required loads within their voltage ratings under all conditions within

their design basis. The licensees reviewed their undervoltage relay setpoints

on each of these occasions. In 1981, the NRC issued Branch Technical

Position, Power System Branch-1, "Adequacy of Station Electric Distribution

System Voltages," which discussed, among other things, the addition of a

second undervoltage relay with an associated time delay. Between 1981 and

1992, the NRC issued two information notices, in which it discussed

undervoltage relay setpoints and other concerns:

1. IN 84-02, "Operating a Nuclear Power Plant at Voltage

Levels Lower than Analyzed," issued January 10, 1984.

2. IN 91-29, "Deficiencies Identified During Electrical Distribution

System Functional Inspections," issued April 15, 1991.

9312150073 PDR E No4tEC 93-0 1 e ' , t

IN 93-99 December 21, 1993 3. IN 91-29, Supplement 1, TDeficiencies Identified During

-- 93-99

"VIN

December 21, 1993 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.

Bran K. rimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

Attachment 1 IN 93-99 December 21, 1993 Representative List of Undervoltaqe Relay Set Point Revision Notifications and

Technical Specification Change Proposals for 1988-1993 Event Notification Licensee Event Notification Date

Number

11374 Pilgrim 1 January 30, 1988 1

14043 Pilgrim 1 November 18, 1988 5

00000 Pilgrim 1 June 30, 1988 1

14780 Cooper 1 February 17, 1989 5

16540 Crystal River 3 September 8, 1989 1

17121 Robinson 2 November 16, 1989 1

18322 Oconee 1, 2 and 3 April 24, 1990 5

18466 McGuire 1 and 2 May 14, 1990 1

18892 St. Lucie 2 July 14, 1990 2

19023 Haddam Neck 1 August 2, 1990 5

20021 Calvert Cliff 1 and 2 December 6, 1990 1

20435 Ft. Calhoun February 12, 1991 1

20503 Kewaunee 1 February 20, 1991 5

20542 Salem 2 February 27, 1991 2

21691 Dresden 2 and 3 August 23, 1991 5

22281 Dresden 2 November 20, 1991 1

22498 Zion 1 and 2 December 19, 1991 5

22580 Indian Point 3 January 9, 1992

22658 Dresden 3 January 22, 1992

22847 (TOL) Washington Nuclear 2 February 19, 1992

22918 Washington Nuclear 2 March 1, 1992

23148 Vermont Yankee April 1, 1992

23191 Quad Cities 1 and 2 April 7, 1992

23338 LaSalle 1 and 2 April 27, 1992

23365 LaSalle 2 April 29, 1992

23385 Crystal River 3 May 1, 1992

23439 (TOL) Grand Gulf May 11, 1992

23452 Comanche Peak 2 May 13, 1992

23576 Crystal River 3 June 4, 1992

23784 Zion 1 and 2 July 2, 1992

23932 Byron 1 and 2 July 24, 1992

00000 Callaway July 23, 1992

24229 Crystal River 3 September 14, 1992

24384 Dresden 2 and 3 October 6, 1992

• TOL - Thermal Overload

Attachment 1 IN 93-99 December 21, 1993 Event Notification Licensee Event Notification Date Class

Number

00000 Prairie Island 1 & 2 November 6, 1992 1

00000 St. Lucie 1 November 30, 1992 1

24757 Maine Yankee December 15, 1992 5

00000 Diablo Canyon 1 and 2 December 22, 1992 1

24845 Point Beach 1 and 2 January 7, 1993 1

25248 (TOL) Pilgrim March 29, 1993 5

25362 South Texas April 6, 1993 5 Events Notification Number-00000 Licensees whose undervoltage relay setpoint

notifications to the NRC were reported by LERs, licensee letter, etc., and

event notification numbers if any, were not known.

Class Definitions:

1. Undervoltage Relay setpoints were found to be incorrect because of

design errors.

2. Undervoltage Relay setpoints, as found, were not the same as required by

the technical specification.

3. Safety load circuit breaker thermal overloads or other trip setpoints

were too low because of design errors.

4. Safety load circuit breaker thermal overload, or other trip setpoints, as found, were not the same as required by the technical specification.

5. Membership in one of the preceding four classes could not be definitely

established because of incomplete information in the event notification.

Att~ehment 2 IN 93-99 December 21, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

93-98 Motor Brakes on Valve 12/20/93 All holders of OLs and CPs

Actuator Motors for nuclear power reactors.

93-97 Failures of Yokes 12/17/93 All holders of OLs or CPs

Installed on Walworth for nuclear power reactors.

Gate and Globe Valves

93-96 Improper Reset Causes 12/14/93 All holders of OLs or CPs

Emergency Diesel for nuclear power reactors.

Generator Failures

93-95 Storm-Related Loss of 12/13/93 All holders of OLs or CPs

Offsite Power Events for nuclear power reactors

due to Salt Buildup located close to a large

on Switchyard Insulators body of salt water.

93-94 Unauthorized Forced 12/09/93 All holders of OLs or CPs

Entry into the Pro- for nuclear power reactors.

tected Area at Three

Mile Island Unit 1 on

February 7, 1993

93-93 Inadequate Control of 12/08/93 All holders of OLs or CPs

Reactor Coolant System for nuclear power reactors.

Conditions During Shutdown

93-92 Plant Improvements to 12/07/93 All holders of OLs or CPs

Mitigate Common Depend- for nuclear power reactors.

encies in Component

Cooling Water Systems

91-21, Inadequate Quality 12/07/93 All holders of OLs or CPs

Supp. 1 Assurance Program of for nuclear power reactors

Vendor Supplying and all recipients of

Safety-Related Equipment NUREG-0040, 'License Con- tractor and Vendor Inspec- tion Status ReportR (White

Book)..

OL - Operating License

CP = Construction Permit

IN 93-99 December 21, 1993 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.

Odginal signed by

Brian K.Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

E plion:

The stress laid by the initial reviewer on the degree of concern that

licensees and the staff should feel for such a widespread and persistent

preblem, viz. low UVR set points, has been all but eliminated from the

present IN.

• C.MORRIS (S/D) (SEE PREVIOUS CONC.)

15 NOV. 93

• SEE PREVIOUS CONCURRENCES

• DO RS/OGCB

• C/OGCB:DORS:NRR D/DORS:NRR

NCampbell GHMarcus

07/30/93 08/10/93 12//$193

• EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE: NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 95/19/93 05/19/93 07/23/93 07/13/93

1. Concurred in electronically by JMain.

DOC NAME: 93-99.IN

IN 93-XX

November XX, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

Exception:

The stress laid by the initial reviewer on the degree of concern that

licensees and the staff should feel for such a widespread and persistent

problem, viz. low UVR set points, has been all but eliminated from the

present IN. G4'

C.MORRIS

15 NOV. 93 Document Name: G:\SHARED\R3UNRELS.IN

• SEE PREVIOUS CONCURRENCES # Concurred in electronically by JMain.

D/DORS:NRR *C/OGCB: DORS:NRR *OGCB:DORS:NRR

BKGrimes GHMarcus NCampbell

11/ /93 A 08/10/93 07/30/93

• EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

&Wp: 4 & Lso1

IN 93-XX

November XX, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

Document Name: G:\SHARED\R3UNRELS.IN

• SEE PREVIOUS CONCURRENCES # Concurred in electronically by JMain.

D/DORS:NRR *C/OGCB:DWRS:NRR *OGCB: DORS:NRR

BKGrimes GHMarcus NCampbell

ll/ /93 08/10/93 07/30/93

• EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

IN 93-XX

August XX, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

Document Name: UNRELSET.IN DORS/OGCB D/DORS: C/OGCB: DORS:NRR

NCampbell BKGrime GHMarcus6#/W

07/30/93 08/ /93 08/to /93

• EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE :NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

1. Concurred in electronically by JMain.

IN 93-XX

August XX, 1993 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.

Brian K. Grimes, Director

Division of Operational Events

Assessment

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

Document Name: UNRELSET.IN DRS/OGCB D/DORS:NRR C/OGCB:DORS:NRR

NCampbell BKGrimes GHMarcus

07/8* /93 07/ /93 07/ /93

• EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

1. Concurred in electronically by JMain.

_> K_> IN 93-XX

July XX, 1993 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.

Brian K. Grimes, Director

Division of Operational Events

Assessment

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

Document Name: UNRELSET.IN DORS/OGCB D/DORS:NRR

NCampbell BIKGrimes Marcus

07/ /93 0,7/ /24 T/ /93

• EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger Tech Ed

04/28/93 05/19/93 05/19/93 07/13/93

1. Concurred in electronically by JMain.