Information Notice 1997-69, Reactor Trip Breakers & Surveillance Testing of Auxiliary Contacts
K)
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 ct'
I
K'J
Attachment
September 19, 1997 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
97-68
97-67
Loss of Control of
Diver in a Spent
Fuel Storage Pool
Failure to Satisfy
Requirements for
Significant Manipula- tions of the Controls
for Power Reactor
Operator Licensing
Failure to Provide
Special Lenses for
Operators Using
Respirator or Self-
Contained Breathing
Apparatus During
Emergency Operations
Failures of High-Dose- Rate (HDR) Remote After- loading Device Source
Guide Tubes, Catheters, and Applicators
09/03/97
08/21/97
08/20/97
08/15/97
Holders of a facility
or construction permit
issued for a power
reactor pursuant to
10 CFR Part 50
All holders of OLs for
nuclear power reactors
except those who have
permanently ceased
operations and have
certified that fuel has
been permanently removed
from the reactor vessel
All holders of operating licenses
or construction permits for
nuclear power and non-power
reactors and all licensed reactor
operators and senior operators
All high-dose-rate (HDR)
remote afterloader licensees
97-66
97-65
97-64
Potential Problems
Associated with Loss
of Electrical Power
in Certain Teletherapy
Units
08/13/97
All U.S. Nuclear Regulatory
Commission medical tele- therapy licensees
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"
No copy
- Ali
OFFICE
Tech Contacts I
C:EELB
I
(A)C:PECB I
A)D:DRPM
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
11 M
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'
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
08/ /97 OFFICIAL RECORD COPY} llx~
kglfI
M
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 R
ECURD 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
CPetronU
_ alvo t
Achaffee
MSlosson
MShannon, II
d
DATE
07/11/97 V17 /97
07/
/97
07/ /97 Asr
OFFICIAL RECORD COPY