Information Notice 1997-69, Reactor Trip Breakers & Surveillance Testing of Auxiliary Contacts

Reactor Trip Breakers & Surveillance Testing of Auxiliary Contacts

ML031050118
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:	09/19/1997
From:	Roe J Office of Nuclear Reactor Regulation
To:
References
IN-97-069, NUDOCS 9709160253
Download: ML031050118 (8)

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 - 0001 September 19, 1997 NRC INFORMATION NOTICE 97-69: REACTOR TRIP BREAKERS AND SURVEILLANCE

TESTING OF AUXILIARY

CONTACT

S

Addressees

All holders of operating licenses for pressurized water reactors (PWRs) except those who

have permanently ceased operations and have certified that fuel has been permanently

removed from the reactor vessel.

Purpose

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

addressees that three licensees have recently identified potential problems regarding

Westinghouse Type DB50 reactor trip breaker (RTB) maintenance or surveillance testing or

both. 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 September 19, 1996, with Sequoyah Unit 2 at 100 percent power, the Unit 2 "B" RTB was

removed from service for routine preventive maintenance and was replaced with a spare

RTB. After the preventive maintenance and the post-maintenance surveillance testing was

completed, the spare RTB was removed and replaced by the refurbished RTB. When the

refurbished RTB was returned to service, the control room operators reported an

unanticipated annunciator. An investigation indicated a malfunction of the RTB auxiliary

contacts. Subsequent inspection of the refurbished RTB by the licensee determined that the

linkage control to the auxiliary contacts had not been reconnected during the breaker

refurbishment activities. As a result, the refurbished RTB had been in service with the

auxiliary contacts inoperable for approximately nine hours, which exceeded the technical

specifications limiting conditions for operations (LCO) action time of six hours for the reactor

trip system interlock (P4). Inadequate post-maintenance testing permitted the RTB to be

returned to service with an inoperable P4 interlock. This was first reported as an unresolved

item in NRC Inspection Report (IR) 50-327/328-97-01 (Accession No. 9704010175) and later

identified as a Severity Level IV violation in IR 50-327/328-97-03 (Accession No.

9705190286).

On January 13, 1997, with Watts Bar Unit 1 operating in Mode 1 at 100 percent power, the

licensee determined that because of a misinterpretation of technical specifications, the

97 Cke e+v ,

,~ 2 3t

IN 97-69 September 19, 1997 surveillance testing requirements for the RTB auxiliary contacts, which provide a turbine trip

signal on reactor trip (PA interlock), were not being performed. On February 10, 1997, the

licensee reported this in Licensee Event Report (LER) 50-390/97-001, (Accession No.

9702180273).

On January 22, 1997, with Vogtle Unit 1 operating in Mode 1 at 100 percent power, the

licensee discovered that a portion of the RTB auxiliary contacts, which produce the turbine

trip signal on reactor trip (P-4 interlock), were not being tested as required by technical

specifications. On February 20, 1997, the licensee reported this in LER 50.424/97-002 (Accession No. 9702240448).

Discussion

The Westinghouse Type DB50 RTB assembly has three auxiliary relays that are mechanically

connected to the breaker by linkages. The relays are arranged in a vertical stack. The

bottom relay is connected to the breaker by an inertia latch linkage, with a separate linkage

connecting the bottom relay to the two upper relays.

Bench inspection of the failed Sequoyah RTB revealed that the linkage necessary to operate

the two upper sets of auxiliary relays was not connected which rendered the contacts

associated with those two relays inoperable. The contacts provide a portion of the P4 interlock. With the reactor trip breakers open, the interlock, among other things, causes a

feedwater isolation with low Tave and a turbine trip. Before the refurbished RTB was

installed, the breaker had been opened and closed several times by maintenance personnel

who did not notice the disconnected linkage which was in a location that was difficult to see.

Visual inspections of the refurbished RTB, performed with the breaker in service, also did not

reveal any discrepancies.

The Westinghouse vendor manual contained instructions for RTB refurbishment, including

steps to test the auxiliary contacts and lubricate the linkages. The vendor instructions were

written in sequence to first verify proper auxiliary relay operation, then lubricate the inertia

latch linkages using a spray lubricant. Since the use of the spray lubricant did not require

disassembly, no instructions for disassembly or reassembly were included in the vendor

procedure. In addition, the contact verification steps, performed before the lubrication

process, were not repeated following the lubrication steps. The licensee's original

maintenance procedure for RTB refurbishment was prepared using these vendor

recommended details and sequence.

In 1994 a problem with an inertia latch resulted in the failure of the RTB to close on demand.

Investigation revealed that a loss of plating on the inertia latch had subjected the parts to

corrosion and had resulted in binding of the latch linkage. As a corrective action, the

licensee revised their procedure to add requirements to disassemble the breaker in order to

inspect and lubricate the Inertia latch linkages. At that time it was not recognized that the

linkage from the bottom relay to the two upper relays could become disengaged when the

adjacent linkage was removed for lubrication. Therefore, the steps necessary to verify proper

'J

IN 97-69 September 19, 1997 operation of the auxiliary contacts were left in the original sequence, i.e., they were

performed before the disassembly of the linkage for lubrication. The procedure should have

been revised to ensure proper operation of the auxiliary contacts was verified after

re-assembly.

The technical specifications require the turbine trip contacts and the engineered safety

feature actuation system contacts (PA interlock) of an RTB to be operable. Westinghouse

has recommended testing the proper operation of the PA contacts following breaker

refurbishment or maintenance activities, and following breaker operation. The testing should

verify that the RTB P4 contacts are in the correct position with the breaker opened and with

the breakers closed.

Licensees may wish to review RTB surveillance and post-maintenance test procedures to

ensure adequate verification of auxiliary contact operation for both the opened and dosed

breaker positions.

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.

Ask W. Roe, Acting Director

(DI.ision of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: M. C. Shannon, RII

(423) 842-8001 E-mail: mxsl@nrc.gov

Robert D. Starkey, RH

(423) 842-8001 E-mail: drsenrc.gov

Attachment: List of Recently Issued NRC Information Notices

'.6 Ict'

K'J

Attachment

IN 97-69 September 19, 1997 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

97-68 Loss of Control of 09/03/97 Holders of a facility

Diver in a Spent or construction permit

Fuel Storage Pool issued for a power

reactor pursuant to

10 CFR Part 50

97-67 Failure to Satisfy 08/21/97 All holders of OLs for

Requirements for nuclear power reactors

Significant Manipula- except those who have

tions of the Controls permanently ceased

for Power Reactor operations and have

Operator Licensing certified that fuel has

been permanently removed

from the reactor vessel

97-66 Failure to Provide 08/20/97 All holders of operating licenses

Special Lenses for or construction permits for

Operators Using nuclear power and non-power

Respirator or Self- reactors and all licensed reactor

Contained Breathing operators and senior operators

Apparatus During

Emergency Operations

97-65 Failures of High-Dose- 08/15/97 All high-dose-rate (HDR)

Rate (HDR) Remote After- remote afterloader licensees

loading Device Source

Guide Tubes, Catheters, and Applicators

97-64 Potential Problems 08/13/97 All U.S. Nuclear Regulatory

Associated with Loss Commission medical tele- of Electrical Power therapy licensees

in Certain Teletherapy

Units

OL = Operating License

CP = Construction Permit

IN 97-69 x<j

ASeptember 19, 1997 operation of the auxiliary contacts were left in the original sequence, i.e., they were

performed before the disassembly of the linkage for lubrication. The procedure should have

been revised to ensure proper operation of the auxiliary contadts was verified after

re-assembly.

The technical specifications require the turbine trip contacts and the engineered safety

feature actuation system contacts (P-4 interlock) of an RTB to be operable. Westinghouse

has recommended testing the proper operation of the P4 contacts following breaker

refurbishment or maintenance activities, and following breaker operation. The testing should

verify that the RTB P4 contacts are in the correct position with the breaker opened and with

the breakers closed.

Licensees may wish to review RTB surveillance and post-maintenance test procedures to

ensure adequate verification of auxiliary contact operation for both the opened and closed

breaker positions.

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.

original signed by

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: M. C. Shannon, RII

(423) 842-8001 E-mail: mxsl@nrc.gov

Robert D. Starkey, RHI

(423) 842-8001 E-mail: drs~nrc.gov

Attachment: List of Recently Issued NRC Information Notices

Tech Editor has reviewed and concurred on 07/29/97 DOCUMENT NAME: 97-69.IN

To receive a copy of this document, Indicate In the box: "C' w Copy without enclosures "E" u Copy with en I ures "N" M

No copy *;Ali

OFFICE Tech Contacts I C:EELB I (A)C:PECB I A)D:DRPM 11 NAME CPetrone, JCalvo* _RDennig* JRoe

8126/97*'

MShannon, RII* A<

DATE 107/31/97 08/07/97 08/27/97 0P 16/97 OFFICIAL RECORD COPY

IN 97-xx

__ August xx, 1997 operation of the auxiliary contacts were left in the original sequence, i.e., they were

performed before the disassembly of the linkage for lubrication. The procedure should have

been revised to ensure proper operation of the auxiliary contacts was verified after

re-assembly.

The technical specifications require the turbine trip contacts and the engineered safety

feature actuation system contacts (P4 interlock) of an RTB to be operable. Westinghouse

has recommended testing the proper operation of the P4 contacts following breaker

refurbishment or maintenance activities, and following breaker operation. The testing should

verify that the RTB P-4 contacts are in the correct position with the breaker opened and with

the breakers closed.

Licensees may wish to review RTB surveillance and post-maintenance test procedures to

ensure adequate verification of auxiliary contact operation for both the opened and closed

breaker positions.

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.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: M. C. Shannon, RII

(423) 842-8001 E-mail: mxslnrc.gov

Robert D. Starkey, RHI

(423) 842-8001 E-mail: drs@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: GACDP\BREAKER.IN

To receive a copy of this document, Indicate In the box: "C' - Copy without enclosures "E" - Copy with enclosures "W' M

No copy

OFFICE Tech Contacts I C:EELB I (A)C:PECB I A)D:DRPM

[ I

NAME CPetrone, JCalvo* RDennig* JRoe

8/26/97*

MShannon. RII*

DATE 07/31/97 08/07/97 08/27/97 OFFICIAL RECORD COPY}

llx~kglfI 08/ /97

IN 97-xx

-j .August xx, 1997 operation of the auxiliary contacts were left in the original sequence, i.e., they were

performed before the disassembly of the linkage for lubrication. The procedure should have

been revised to ensure proper operation of the auxiliary contacts was verified after

re-assembly.

The technical specifications require the turbine trip contacts and the engineered safety

feature actuation system contacts (P4 interlock) of an RTB to be operable. Westinghouse

has recommended testing the proper operation of the P-4 contacts following breaker

refurbishment or maintenance activities, and following breaker operation. The testing should

venfy that the RTB P-4 contacts are in the correct position with the breaker opened and with

the breakers closed.

Licensees may wish to review RTB surveillance and post-maintenance test procedures to

ensure adequate verification of auxiliary contact operation for both the opened and dosed

breaker positions.

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.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: M. C. Shannon, Ril Robert D. Starkey, Ril

423-842-8001 423-842-8001 E-mail: mxsl@nrc.gov E-mail: drs@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: G:\CDP\BREAKER.IN

To receive a copy of this docunent, Indicate In the box: 'C" - Copy without enclosures 'E" - copy with enclosures N"-- No copy

OFFICE Tech Contacts I C:EELB I (A)Q-MB/kJ\ (A)D:DRPM I

NAME CPetrone. JCalvo* JRoe

8/26/97* Roes

______ MShannon. RII* _

,DATE 07/31/97 08/07/97 08/;7 f97 L08/ /97 OFI--CIAL RECURD COPY

IN 97-xx

'August xx, 1997 and following breaker operation. Th$ esting should verify that/he RTB P4 contacts are in

the correct position with the breaker op ed and with the bra kers closed.

On September 19, 1996, Sequoyah Unit 2 placed an RTB *th a refurbished breaker and

returned the RTB to service without having tested to verify rrect contact position for both

the opened and closed breaker positions. As result, the furbished RTB was in service, with the auxiliary contacts inoperable, for appro mately nie hours, which exceeded LCO

action time.

On January 13, 1997, Watts Bar Unit 1 reported in *ce see Event Report (LER) 50-424/97-

001, that because of a misinterpretation of technical s cifications, the surveillance testing

requirements for the RTB auxiliary contacts, which p e a turbine trip signal on reactor trip

(PA4 interlock), were not being performed.

On January 22, 1997, Vogtle Unit 1 reported in LE, 50-390 7-02, that a portion of the RTB

auxiliary contacts, which produce the turbine trip si nal on re or trip (P4 interlock), were

not being tested as required by technical specifica ons.

Licensees may wish to review RTB surveillance d post mainten ce test procedures to

ensure adequate verification of auxiliary contact peration for both ened and closed

breaker positions.

This information notice requires no specific act n or written response. Iou have any

questions about the information in this notice, lease contact the Technica Contact listed

below or the appropriate Office of Nuclear Re ctor Regulation (NRR) Proje anager.

Marylee M. Sloon Acting Director

Division of React rogram Management

Office of Nuclear or Regulation

Technical Contacts: M. C. Shannon, RII

423-842-8001 e-mail: MXSI@nrc.gov , fd

Robert D. Starkey, RHI

423-842-8001 e-mail: JMS@nrc.gov J&w A

Attachment: List of Recently Issued NRC In aton Notices

DOCUMENT NAME: G:ACDPBREAKER.IN

To receive a copy of this document, Indicate In the bo C" -Copy without enclosures "Er copy with enclosures "N"- No copy

OFFICE Tech

1 C :EELB C:PECB (A)D:DRPM

Contacts "ZZC I

NAME _ alvo t

CPetronU Achaffee MSlosson

MShannon, II d

DATE 07/11/97 V17 /97 07/ /97 07/ /97 Asr OFFICIAL RECORD COPY