Part 21 Report - 1998-105
ACCESSION #: 9806080209
LICENSEE EVENT REPORT (LER)
FACILITY NAME: Indian Point 3 PAGE: 1 OF 15
DOCKET NUMBER: 05000286
TITLE: 480 Volt Bus Inoperable Due to a Failure of the 32
Residual Heat Removal Pump Circuit Breaker to Open; A
Condition Prohibited by Technical Specifications
EVENT DATE: 12/18/97 LER #: 97-032-02 REPORT DATE: 05/28/98
OTHER FACILITIES INVOLVED: DOCKET NO: 05000
OPERATING MODE: N POWER LEVEL: 100
THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR SECTION:
50.73(a)(2)(i) & OTHER
LICENSEE CONTACT FOR THIS LER:
NAME: Angelo Vai, Design Analysis, TELEPHONE: (914) 788-2647
Electrical Engineering Supervisor
COMPONENT FAILURE DESCRIPTION:
CAUSE: X SYSTEM: ED COMPONENT: BKR MANUFACTURER: W120
REPORTABLE TO NPRDS: Yes
SUPPLEMENTAL REPORT EXPECTED: NO
ABSTRACT:
On December 18, 1997, with reactor power at 100 percent, a plant shutdown
was initiated in accordance with the Technical Specifications (TS).
Following a surveillance test, the breaker used to power the 32 Residual
Heat Removal (RHR) pump could not be opened. Operations concluded that
the breaker was not capable of opening and shedding the 32 RHR pump from
its associated safety bus following a safety injection or undervoltage
signal, therefore, the safety bus could be rendered inoperable. Because
the TS do not provide an allowed outage time for an inoperable safety
bus, the plant was brought to hot shutdown. On December 22, during
testing of additional breakers, another breaker was determined to be
potentially degraded. Engineering determined that other breakers could
be subject to failure and result in overload of the three emergency
diesel generators (EDG). Operations declared the three EDGs inoperable
and brought the plant to cold shutdown. The cause of the breaker failure
was lack of lubrication at key pivot connections in the breaker
mechanism. The missing lubrication was due to a lack of knowledge by the
breaker overhaul vendor. A contributing cause was a unique combination
of wear, tolerances and adjustments of breaker parts that permitted
linkages within the breaker to overtravel to a position where small
changes in frictional forces affected the breaker trip capability.
Corrective actions include; breaker replacement, testing of like
breakers, equipment failure evaluation, development of a process to
test/inspect overhauled breakers, and expedite the PM for the vendor
overhauled breakers. This report is also a 10 CFR Part 21 notification.
There was no effect on public health and safety.
END OF ABSTRACT
TEXT PAGE 2 OF 15
Note: The Energy Industry Identification System Codes are identified
within the brackets { }
DESCRIPTION OF EVENT
On December 18, 1997, at approximately 1050 hours, with reactor power at
100 percent, operators attempted to secure the 32 Residual Heat Removal
(RHR) {BP} pump {P} from the control room after completing a monthly
functional test. The electrical circuit breaker {BKR} used to power the
pump (52/RHR2) from 480 volt AC {ED} bus 6A {BU} would not open.
Operators attempted to secure the pump locally from the 480 volt AC
switchgear room without success. Operations concluded the breaker was
not capable of opening and shedding the 32 RHR pump from its associated
safety bus following a safety injection or loss of offsite power signal.
Without knowing the cause of the breaker problem, operations concluded
the RHR pump and its safety bus could be rendered inoperable. The 32 RHR
pump and 480 volt bus 6A were declared inoperable at approximately 1050
hours. The Technical Specifications (TS) do not provide an allowed
outage time (AOT) for an inoperable safety bus, therefore TS 3.0 was
entered. At approximately 1145 hours, Operations initiated a plant
shutdown in accordance with the TS. Emergency Diesel Generator (EDG)
{EK} 32, which supplies emergency power to bus 6A, was declared
inoperable at approximately 1308 hours, and its control switch taken to
trip pull out. At approximately 1233 hours, Operations provided a
one-hour non-emergency notification to the NRC reporting a TS required
shutdown (See ENS Report No. 33425). At approximately 1324 hours, the 32
RHR pump breaker opened without operator assistance. operations declared
bus 6A operable at approximately 1344 hours. In accordance with normal
plant operating procedures the turbine was manually tripped at
approximately 1352 hours, the reactor was shut down and the hot shutdown
condition was achieved at approximately 1428 hours. The 32 EDG was
declared operable at 1540 hours. Although declared inoperable, bus 6A
remained energized during this time period.
During the shutdown all control rods {AA} fully inserted and no
engineered safety feature actuated as a result of the event. Primary
systems functioned properly, except during plant shutdown, at
approximately 1230 hours, control rod (CR) {AA} F-2 in control bank "D"
dropped to zero steps at approximately 70 percent reactor power.
Operators observed a flux tilt of greater than the TS limit of 1.09 from
the Nuclear Instrumentation System (NIS) {IG} power range high flux
detectors {DET} and control room alarms {ALM}, "(NIS) Power Range Dropped
Rod - Rod Stop," and "Rod Bottom - Rod Stop." Operations entered the
appropriate procedures for a dropped rod.
TEXT PAGE 3 OF 15
Also, at 1230 hours, a turbine runback occurred from approximately 70
percent to approximately 61 percent reactor power. The FSAR section for
a dropped rod (14.1.4) states that a turbine runback is prevented below
70 percent reactor power. Engineering recorded the CR drop and runback
event in deviation event reports (DER 97-2876 and 97-2885) and initiated
an investigation.
Operators recorded the failed breaker event in DER 97-2872, commenced a
post trip/transient evaluation (Report No. 97-6), and initiated equipment
failure evaluations (EFE) and investigations of the event. Maintenance
removed the failed breaker from its cubicle in 480 volt Switchgear bus 6A
and replaced it with a spare breaker. After testing the replacement
breaker, the 32 RHR pump was declared operable and its Limiting Condition
for Operation (LCO) action statement exited on December 18, at 2229
hours. The failed breaker was visually inspected, tested and evaluated
by an inspection team, which included plant and vendor personnel, to
determine the cause of the failure.
Instrumentation and Control (I&C) personnel performed troubleshooting of
the dropped CR and verified electrical circuit integrity from the CR
power cabinet to the CR coil stacks. A failed movable gripper coil
blocking diode CR1 (A26 Assembly) was discovered in CR power cabinet 1BD.
Further troubleshooting discovered a total of 12 additional failed diodes
in other movable gripper assemblies. I&C postulated, with assistance
from Westinghouse, that the failure of the 12 diodes was caused by
parallel voltage traps which were not functional. I&C further postulates
that the diode associated with control rod F-2 was an intermittent
failure which may have caused an interruption in the current flow to the
movable gripper assembly. Westinghouse also postulated that the dropped
rod may have been the result of a particle interfering with the required
movement of the movable gripper assembly.
Engineering's investigation of the turbine runback concluded that the
setpoint on the pressure switches {PS} associated with the load limit
valves (LLV1 and LLV2) of the turbine control oil system {TG} for runback
termination were set too low.
The faulty breaker for the 32 RHR pump (52/RHR2) is a 480 volt AC safety
related electrical circuit breaker, model DS-416, manufactured by
Westinghouse {120} (NYPA ID No. A1033). Westinghouse divested itself of
new breaker manufacturing which was procured by Cutler-Hammer Inc.
(C770). Westinghouse continues to refurbish breakers. The firm that
overhauled breaker A1033 was Power Distribution Technologies (PDT). PDT
was a subsidiary of Framatome (F185) but is no longer in business,
TEXT PAGE 4 OF 15
The initial investigation of the faulty breaker did not yield a specific
cause, but possible causal factors. To address possibility that the
condition may be present in other similar breakers, Engineering developed
a sampling plan and a test procedure to determine if there was an extent
of condition. The test procedure required cycling the breakers open and
close, with and without the breaker's pole shaft reset spring installed.
Testing a breaker without its pole shaft reset spring, which provides
additional forces to open the breaker, is not a normal configuration for
a DS-416 breaker. Engineering concluded that testing without the breaker
pole shaft reset spring provided an indication of the additional margin
of assurance that the breaker would open when a trip signal was
initiated. The pole shaft reset spring is part of the breaker design
configuration, but removal for testing was based on a suggestion by an
employee of the breaker manufacturer, based on a Westinghouse Technical
Bulletin for a different type breaker.
On December 20, Engineering initiated testing of breakers in accordance
with the sample plan to determine if they were functioning properly. On
December 23, 1997, Operations was notified that a DS-416 breaker (A1042)
did not trip with its pole shaft reset spring removed. The breaker
(A1042) normally powers the 33 pressurizer backup heater {AB}(52/PBU3).
Engineering could not, at that time, provide a reasonable expectation of
operability for other DS-416, 480 volt AC safety related electrical
circuit breakers used to power plant safety equipment. Without test
results for the remaining 480 volt DS-416 breakers, Operations concluded
there were an unknown number of breakers that may have been in a degraded
condition. The plant design requires that plant loads be shed and then
sequenced onto their assigned 480 volt AC safety buses for proper
Emergency Diesel Generator (EDG) operation. Without assurance of proper
breaker operation, on December 23, at approximately 0300 hours,
Operations conservatively declared the three EDGs inoperable and
initiated plant cooldown to the cold shutdown condition. Cold shutdown
was achieved on December 24, 1997, at approximately 0240 hours.
As a result of finding the 33 pressurizer backup heater breaker (A1042)
potentially degraded, Engineering developed a revised sampling plan that
included additional breaker testing and measurements of breaker
components. Testing and evaluation of the failed breaker (A1033)
revealed that it would not repeat its failure in its design configuration
(pole shaft reset spring installed). With the breaker's pole shaft reset
spring removed, the failed breaker (A1033) would repeatedly fail to trip.
Testing of the expanded sample breaker population showed that the
remaining DS-416 breakers in the test sample satisfactorily tripped in
their design configuration.
TEXT PAGE 5 OF 15
Four breakers were identified as potentially degraded when tested with
their pole shaft reset spring removed and they were replaced. on
December 26, Engineering performed an operability determination (OD)
which concluded the breakers were operable. Operations declared the EDGs
operable and exited the LCO on December 26, at approximately 1925 hours.
The testing that was performed for the extent of condition failure
evaluation provided assurance that the remainder of the installed DS-416
breakers would operate as designed in their normal configuration (pole
shaft reset spring installed). There are 60 DS-416 breakers installed in
safety related applications. Post event review of Authority
documentation determined that 17 of the installed breakers were
overhauled by PDT. As a result of the event and extent of condition
testing, two breakers (A1033, A1042) were removed. Breakers other than
A1033 and A1042 that were overhauled by PDT were suspected of not having
the proper lubrication. Consequently, those remaining breakers whose
documentation indicated an overhaul by PDT were tested with the pole
shaft reset spring installed and removed. Testing of the remaining PDT
overhauled 480 volt breakers was satisfactory. Three other breakers of
the expanded sample set that were overhauled by Westinghouse the Original
Equipment Manufacturer (OEM) tripped with their pole shaft reset spring
installed, but did not consistently trip with the pole shaft reset spring
disconnected . The OEM considered a successful test with the reset
spring installed as acceptable. Engineering concurred with the OEM since
the OEM was aware of the lubrication requirements. The successful
operation of the remaining PDT overhauled breakers during testing with
their pole shaft reset spring removed provided confidence that these
breakers would provide reliable operation. An inspection of seven
breakers was performed to determine if Poxylube was evident. Breaker
A1042 was the only breaker of the test sample that did not have the
Poxylube lubricant present on all the key pivot points. Breaker A1033
and A1042 were part of the breaker population overhauled by PDT in 1994.
The remaining sampled breakers were either overhauled by the OEM or had
not had an overhaul performed. The OEM confirmed that after final
testing, prior to shipment, a refurbished breaker will not contain a
lockup condition. Because the lack of lubrication was attributable to a
non-OEM vendor, the breaker history was investigated. Engineering
identified two other non-OEM vendors besides PDT, Nuclear Logistics Inc.
(NLI), and Satin American Co. (SAC). Thirteen breakers were supplied by
NLI, two of which were installed and used in safety applications. These
two NLI breakers were removed, tested and verified properly lubricated
and capable of opening with and without their pole shaft reset spring.
TEXT PAGE 6 OF 15
The remaining 11 breakers are spares and were verified as properly
lubricated. In 1984 and 1985, SAC was used to refurbish four breakers
one of which was permanently removed and the other three subsequently
overhauled by others [See Information Notices 89-45, and IN 93-73].
As a result of troubleshooting and assessment of the dropped rod event,
the control rod movable gripper coil diodes and VR-10 voltage traps were
replaced for all of the control rods. Control rod F-2 drop test timing
was performed satisfactorily. The F-2 rod drop test results were
compared to previously performed rod drop tests for rod F-2 and no
anomalies were identified. All control rod banks were successfully
exercised. Exercising the control rod would have dislodged any particle
interfering with the proper operation of the control rod.
On May 1, during review for Part 21 reporting, two breakers (A1083,
A1114) were identified as having been overhauled by PDT but not tested
during the extent of condition testing. Maintenance Engineering (ME)
confirmed the documentation identifying these breakers as overhauled by
PDT. An OD was performed that concluded breaker A1114 was operable and
that breaker A1083 was a manual breaker used in a non-safety application.
On May 7, ME discovered a PDT label on a breaker after it was removed
from service for preventive maintenance. ME performed an assessment and
determined the breaker for the Containment Recirculation Fan 32 (A1015)
had been overhauled by PDT, but had not been previously identified or
tested. ME performed a plant walkdown of installed DS-416 breakers and
re-assessed breaker work history documentation and walkdown data. ME's
review identified four additional breakers (A1037, A1068, A1020, A1035)
not previously identified as overhauled by PDT. Two breakers (A1037,
A1068) had been tested during the extent of condition testing. Breaker
A1068 was removed from service on March 6, 1998 because it failed to
close on demand during testing. It was not known at the time that A1068
was a PDT overhauled breaker. The cause of breaker A1068 failure was
determined to be binding due to dirt and degraded lubricant. The two
remaining breakers (A1020, A1035) were determined to be operable in an
OD. The difficulty in positively identifying breakers as overhauled by
PDT is a result of a weakness in the identification (ID) system used to
identify breakers. In the past the complete ID number for a breaker was
not always used in a purchase order and its tracking number changed due
to changes in the ID system. As a result, the work history for specific
breakers is difficult to determine. The weakness in the ID system used
to uniquely identify breakers was previously identified in the EFE/Root
Cause report for the 32 RHR breaker and corrective action taken. An
independent re-assessment will confirm that all PDT overhauled breakers
have been identified.
TEXT PAGE 7 OF 15
I&C adjusted the setpoints on the pressure switches associated with the
turbine control oil system load limit valves (LLV1/LLV2) to terminate
turbine runback at 70 percent reactor power.
CAUSE OF EVENT
The cause of the event was a failure of the 32 RHR pump circuit breaker
(A1033) to open on demand. The primary cause of the breaker failure
(A1033) was lack of the manufacturers recommended lubrication (Poxylube)
on key pivot points in the breaker mechanism. This lack of the proper
lubrication resulted in an increase in frictional forces to a point where
the force needed to initiate an opening sequence was not adequate.
A contributing cause of the breaker's failure to open was a unique
combination of parts wear, part tolerances and adjustments that allowed
linkages between the moving contact assemblies and the pole shaft to
over-travel. The combination of higher frictional forces due to improper
lubrication and linkage over-travel caused the breaker to lockup in the
closed position. Inadequate lubrication, binding, and clearances in the
linkage connections (clevises, pins, and support points) increased the
frictional forces that counteracted the trip force and allowed the
linkage to remain in a lockup position. The EFE determined that the
lubricant was removed from the breaker during an overhaul in 1994 by a
non Original Equipment Manufacturer (OEM) vendor, PDT. The EFE concluded
the lubricant was removed as part of PDT's normal cleaning process and
was not reapplied. The failure to reapply the lubricant was due to a
lack of knowledge by the vendor of the lubricant and its critical
function for breaker operation. NYPA also lacked this knowledge. The
original OEM, Westinghouse, considered the application of the lubricant
(Poxylube) as an original factory manufacturing process which was within
the scope of what the OEM considers proprietary information.
The OEM only provides information in their breaker manuals on items they
consider replaceable by the user or those that should be maintained by
the user. Information on parts or assemblies that the OEM considers
factory maintenance or factory replaceable only are not included in the
published documentation. The published Westinghouse breaker manual
states what a utility or vendor (user) can perform. The breaker manual
requires that for any activity not identified, the user should contact
Westinghouse or send the component to Westinghouse for repair or
replacement.
TEXT PAGE 8 OF 15
PDT did not adhere to the OEM manual requirements, and removed parts,
cleaned them and failed to re-apply proper lubrication. The Authority
performed a receipt inspection of the breaker after overhaul but failed
to discover the lack of proper lubrication due to the unpublished
information. Engineering determined the cause of the breaker over-travel
was a combination of OEM specified adjustment criteria applicable to the
insulating links, parts wear and manufacturing tolerances associated with
the pole linkages. Adjustment of the pole insulator linkage lengths
affects whether the linkage will travel far enough to be allowed to
lockup. The cause of the EDGs being declared inoperable was the failure
of breaker A1042 to open with its pole shaft reset spring removed, which
called into question the operability of the remaining DS-416 breakers.
CORRECTIVE ACTIONS
The following corrective actions have been or will be performed to
address the causes identified for this event and prevent recurrence:
o The breaker for the 32 RHR pump was replaced with a spare breaker
and satisfactorily tested.
o A sample set of model DS-416 480 volt AC electrical circuit breakers
were tested, and a sample of breakers had detailed measurements of
selected components and parameters. Four breakers failed to open
with their pole shaft reset spring removed and they were replaced
and satisfactorily tested. Engineering concluded, based on its
investigations and testing, that a unique combination of
circumstances existed with the 32 RHR pump breaker.
o The breaker for the 32 RHR pump (A1033) was initially inspected then
shipped to Westinghouse where a detailed EFE was completed. NYPA
performed a root cause investigation based on the completed EFE.
o An inspection/test process was developed for overhauled breakers
that included the lessons learned. The new inspection/test process
was incorporated into the breaker maintenance procedure.
o The breakers that were overhauled by PDT will be replaced and
refurbished on an expedited schedule. Scheduled completion date for
all but six is August 31, 1998. The remaining Six breakers will be
replaced during the next refueling outage (RO 10).
TEXT PAGE 9 OF 15
ANALYSIS OF EVENT
The event is reportable under 10 CFR 50.73 (a)(2)(i)(B). The licensee
shall report any operation or condition prohibited by the plants TS.
This event meets the reporting criteria because bus 6A was declared
inoperable.
The cause of the breaker failure was not known and although the bus was
energized in accordance with the TS, Operations conservatively concluded
the failed breaker's assigned safety bus 6A could be rendered inoperable.
Because TS 3.7 requires the four 480 volt buses 2A, 3A, 5A, and 6A to be
energized above cold shutdown, but does not have an AOT for an inoperable
480 volt bus, Operations concluded the plant was in a condition that met
the requirements of TS 3.0. TS 3.0, which is similar to Standard
Technical Specification 3.0.3, requires that for LCOs where no exception
time is specified for inoperable components, the time is assumed to be
zero. Operators initiated plant shutdown in accordance with TS 3.0, with
hot shutdown achieved on December 18, 1997, at approximately 1428 hours.
Operations notified the NRC in accordance with 10 CFR 50.72(b)(1)(i)(A)
of the initiation of a nuclear plant shutdown required by the plant's TS
(i.e., TS 3.0). 480 volt bus 6A was declared operable at 1344 hours.
The 32 RHR pump breaker was replaced, tested, and the pump declared
operable on December 18, 1997, at approximately 2229 hours.
Subsequently, on December 22, Operations was notified that during testing
of other breakers for extent of condition, another breaker was determined
to be in a potentially degraded condition when tested in a modified
configuration. Engineering determined that other 480 volt DS-416
breakers could be subject to failure. Because failure of the breakers
assigned to the four safety buses could result in overload of the three
EDGs, Operations declared the three EDGs inoperable on December 23, at
approximately 0300 hours. Operations initiated action to bring the plant
to cold shutdown, which was achieved at 0240 hours on December 24, 1997.
TS 3.7.F.4 requires as a minimum, under all conditions including cold
shutdown that two EDGs be operable. Because three EDGs were declared
inoperable, the plant was in a condition prohibited by TS which would be
reportable under 10 CFR 50.73 (a)(2)(i)(B). However, after successful
testing of applicable breakers the three EDGs were determined to be
operable on December 26, at approximately 1925 hours.
TEXT PAGE 10 OF 15
As described below, an engineering evaluation determined that bus 6A
would not have been overloaded and it remained energized per the TS
although declared inoperable. Also, as previously described, the spring
off test is not a normal configuration and on December 26, engineering
concluded the breakers were operable. Based on these findings, the
Authority is reviewing the requirement to report these events. If upon
further review the Authority concludes that any circumstances are not, we
will supplement this LER.
A review was performed of Licensee Event Reports (LER) over the last
three years. No events reporting failure of 480 volt breakers to open
were identified.
SAFETY SIGNIFICANCE
This event had no significant effect on the health and safety of the
public. There were no actual safety consequences for the event because
the 32 RHR pump was running for a test, but not providing any required
flow. The RHR system is not required to be operating during normal plant
operation at power. An engineering evaluation determined that the run
time of the 32 RHR pump during this event did not affect its operability
or cause undue wear. The bus that powers the 32 RHR pump (bus 6A),
although declared inoperable, remained energized in accordance with the
TS and available for powering assigned loads. The bus was considered
inoperable because it would not shed loads (i.e., 32 RHR pump) and
sequence them in accordance with design for proper EDG operation
(overloading). Other DS-416 breakers would not have failed based on
subsequent testing and investigation of a sample of 480 volt DS-416
breakers that demonstrated their operability. 480 volt bus overloading
would not have occurred and proper EDG operation would have been
maintained.
There were no potential safety consequences for the event because an
engineering evaluation determined that the 32 EDG will perform its design
safety function during a DBA (LOCA with LOOP) with the 32 RHR motor
continuously running due to a failure of its feeder breaker to trip
(open). No overload condition would have occurred. The 32 RHR pump was
running and capable of providing its required flow. The redundant pump
(31 RHR) for the 32 RHR pump was operable and would have performed the
required safety function. The safety related recirculation pumps (2)
inside containment would be used during the recirculation phase of a
LOCA. The RHR pumps would only be used if backup capacity to the
recirculation loop is required. The redundant 480 volt safety buses (bus
SA, 2A/3A) were operable and capable of performing their function during
and after the event.
TEXT PAGE 11 OF 15
The possible use of the defective breaker to power other safety
components was considered. Breaker A1033 was one of six 480 volt
breakers modified to charge on closure. This breaker feature is unique
to specific components that are required to be immediately sequenced onto
a safety bus. Therefore, these modified breakers are only used in six
locations for powering specific safety related components. Engineering
determined that had the A1033 breaker been used in one of the other
designated locations and failed to open, no EDG overload condition would
have occurred.
Use of this set of breakers in other locations is prevented because there
are plant procedures that require the specified breaker be used in its
assigned location. Overload of a bus from other installed PDT overhauled
breakers would not occur because no other sampled breaker failed to
operate properly in its design configuration (pole shaft reset spring
installed). Engineering concluded that other 480 volt DS-416 breakers
would not have failed based on subsequent testing and investigation of a
sample of 480 volt DS-416 breakers that demonstrated their operability.
480 volt bus overloading would not have occurred and proper EDG operation
would have been maintained. Since the 32 RHR breaker provides fault
protection, the effects of an electrical fault on the 32 RHR motor was
evaluated. A postulated electrical fault on the 32 RHR pump motor whose
feed breaker fails to open could result in the loss of its assigned 480
volt bus 6A. This failure scenario is bounded by plant design since the
two remaining 480 volt safety buses (5A and 2A/3A) provide adequate power
for one minimum set of safeguards equipment.
There was no safety impact from the dropped F-2 control rod because the
plant is analyzed for a dropped rod in FSAR Section 14.1 and the analysis
shows that safety limits are not exceeded. The turbine runback did not
have a safety impact because the plant is analyzed for the effects of a
turbine runback and the analysis shows that safety limits are not
exceeded. This analysis is based on a runback from 100 to 70 percent
power. The event was a runback from 70 to 60 percent power which is
bounded by the analysis because it was initiated at a lower power, which
is a less limiting condition.
There was no actual or potential safety impact of the three EDGs being
declared inoperable, based on the subsequent successful testing and
evaluation of other DS-416 breakers. The EDGs remained available and
functional even though they were administratively declared inoperable.
TEXT PAGE 12 OF 15
Reporting of Defects and Noncompliance Pursuant to 10 CFR Part 21
1. NAME AND ADDRESS OF THE INDIVIDUAL INFORMING THE COMMISSION
Robert J. Barrett, Indian Point Unit 3, P.O. Box 337, Buchanan,
N.Y.
2. IDENTIFICATION OF THE FACILITY, THE ACTIVITY, OR BASIC COMPONENT
SUPPLIED FOR SUCH FACILITY OR SUCH ACTIVITY WITHIN THE UNITED STATES
WHICH FAILS TO COMPLY OR CONTAINS A DEFECT
480 volt AC circuit breakers, Westinghouse Model DS-416, overhauled
by Power Distribution Technology (PDT)
3. IDENTIFICATION OF THE FIRM CONSTRUCTING THE FACILITY OR SUPPLYING
THE BASIC COMPONENT WHICH FAILS TO COMPLY OR CONTAINS A DEFECT
Power Distribution Technology (PDT),750 Middle Ground Blvd., Newport
News, VA, 23606 (no longer in business)
4. NATURE OF THE DEFECT OR FAILURE TO COMPLY AND THE SAFETY HAZARD
WHICH IS CREATED OR COULD BE CREATED BY SUCH DEFECT OR FAILURE TO
COMPLY
A 480 volt circuit breaker for the 32 RHR pump (breaker A1033)
failed to open on demand. Further investigations and evaluations
concluded the cause of the failure was missing lubrication at key
pivot points in the breaker mechanism. The lack of lubrication was
determined to be a result of a 1994 breaker overhaul performed by
Power Distribution Technology (PDT). Other breakers were overhauled
by PDT under the same and different purchase orders (Pos).
In 1994, PDT overhauled the breaker for the 32 RHR pump (A1033) and
three (3) other DS-416 breakers in accordance with an Authority
purchase order (PO). That Authority PO contained specific
requirements for lubrication, and a requirement to certify that the
refurbishment was performed to the original OEM technical
requirements. PDT failed to comply with the OEM technical manual
and PO requirements by removing lubricants and not reapplying them.
Without the proper lubrication the breaker is not qualified and may
not operate and perform its function. After further testing,
another breaker (A1042) was considered to be in a degraded
condition. Further investigation determined that breaker A1042
lacked lubrication on pivot points in the breaker mechanism. Both
breakers (A1033 and A1042) were overhauled by PDT in 1994 under an
Authority PO.
TEXT PAGE 13 OF 15
Engineering determined that the A1042 breaker could have been used
in any location requiring a DS-416 breaker except the six locations
that require a breaker with the charge-on-close feature. The
initial failed breaker (A1033) for the 32 RHR pump contained the
charge-on-close feature.
Engineering's evaluation of the deviation concluded it could result
in a substantial safety hazard. Lack of the proper lubrication for
breaker A1042 could have prevented the breaker from performing a
safety function (i.e., open on demand) in several applications.
The defective breaker could have resulted in a loss of a safety
function necessary to mitigate the consequences of an accident, in
the event of an accident due to other causes, considering an
independent single failure. Had breaker A1042 been used to power
the Turbine Oil Pump (52/TAO) and failed to trip open in response to
a DBE with a resultant Loss of Offsite Power (LOOP), the 480 volt
safety bus and/or its assigned EDG could have become overloaded or
faulted. The EDG overload would be due to the additional load from
the Turbine Oil Pump which was required to be shed from its assigned
bus. An independent single failure to a redundant EDG or safety bus
during this postulated event would result in the loss of a second of
three onsite AC power sources.
The plant design requires two on-site AC power sources to supply the
power of one minimum required set of safeguards equipment. This
possible scenario could result in a loss of safety function to the
extent that there would have been a reduction in the degree of
protection provided.
5. THE DATE ON WHICH THE INFORMATION OF SUCH DEFECT OR FAILURE TO
COMPLY WAS OBTAINED
On April 1, 1998, Engineering determined that the information
supplied by Westinghouse in their Equipment Failure Evaluation
report of the 32 RHR breaker dated March 19, 1998, identified a
defect that was a potential 10 CFR Part 21 notification.
TEXT PAGE 14 OF 15
6. IN THE CASE OF A BASIC COMPONENT WHICH CONTAINS A DEFECT OR FAILS TO
COMPLY, THE NUMBER AND LOCATION OF ALL SUCH COMPONENTS IN USE AT,
SUPPLIED FOR, OR BEING SUPPLIED FOR ONE OR MORE FACILITIES OR
ACTIVITIES SUBJECT TO THE REGULATIONS IN THIS PART
The number of DS-416 breakers overhauled by PDT is twenty two (22).
The four breakers that were overhauled by PDT under a 1994 Authority
PO, and their location at the time of the event, are as follows
(includes the failed breaker reported in the event):
A1010, Pressurizer Heater Backup Group 32 (52/PBU2)
A1033, Residual Heat Removal Pump 32 (52/RHR2)
A1042, Pressurizer Heater Backup Group 33 (52/PBU3)
A1062, Rod Power Supply Motor Generator Set 31 (52/MG1)
The following DS-416 breakers are the remaining breakers and their
location at the time of the event with documentation that indicates
they were overhauled by PDT:
A1012, 225KVA Lighting Transformer 32 (52/LT2)
A1015, Containment Recirculation Fan 32 (52/CRF2)
A1016, Pressurizer Heater Backup Group 31 (52/PBU1)
A1020, 225KVA Lighting Transformer 33 (52/LT3)
A1021, Rod Power Supply Motor Generator Set 32 (52/MG2)
A1023, Containment Recirculation Fan 34 (52/CFR4)
A1027, Component Cooling Pump 31 (52/CC1)
A1031, Component Cooling Pump 33 (52/CC3)
A1035, Recirculating Pump 32 (52/R2)
A1037, PAB CB Purge Exhaust Fan 32 (52/EXF2)
A1038, Turbine Auxiliary Oil Pump (52/TAO)
A1049, Safety Injection Pump 33 (52/SI3)
A1053, Service Water Pump 37 Backup (52/SW7)
A1058, Service Water Pump 31 (52/SW1)
A1068, Containment Recirculation Fan 31 (52/CRF1)
A1081, Charging Pump 33 (52/C3)
A1083, 480 Volt Feeder to MCC B (52/313-6C)
A1114, 480 Volt Feeder to MCC 33 (52/MCC3)
In addition to four DS-416 breakers PDT overhauled in 1994, one (1)
DS-532 breaker was also overhauled. This breaker (A1074) is
currently installed as a tie breaker for 480 volt bus 2A to 5A
(52/2ATSA).
TEXT PAGE 15 OF 15
7. THE CORRECTIVE ACTION WHICH HAS BEEN, IS BEING, OR WILL BE TAKEN;
THE NAME OF THE INDIVIDUAL OR ORGANIZATION RESPONSIBLE FOR THE
ACTION; AND THE LENGTH OF TIME THAT HAS BEEN OR WILL BE TAKEN TO
COMPLETE
See the corrective actions which were taken and will be taken, and
their scheduled completion dates discussed in this LER. The
expedited replacement and refurbishment of breakers that were
overhauled by PDT, is the responsibility of the Authority's
Maintenance department.
8. ANY ADVICE RELATED TO THE DEFECT OR FAILURE TO COMPLY ABOUT THE
FACILITY, ACTIVITY, OR BASIC COMPONENT THAT HAS BEEN, IS BEING, OR
WILL BE GIVEN TO PURCHASERS OR LICENSEES
Operating Experience (OE) notices 8712 and 8899 were prepared and
issued on the INPO Nuclear Network on the findings of the failure
evaluation.
*** END OF DOCUMENT ***
Page Last Reviewed/Updated Wednesday, March 24, 2021