ML20138C587
| ML20138C587 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, McGuire  |
| Issue date: | 03/20/1986 |
| From: | Brownlee V, William Orders, Pierson R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20138C563 | List: |
| References | |
| 50-369-85-45, 50-370-85-46, NUDOCS 8604020538 | |
| Download: ML20138C587 (9) | |
See also: IR 05000369/1985045
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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REGION li
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101 MARIETTA STREET.N W.
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ATL ANT A. GEORGI A 30323
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Report Nos.: 50-369/85-45 and 50-370/85-46
Licensee: Duke Power Company
422 South Church Street
Charlotte, NC 28242
Facility Name: McGuire Nuclear Station
Docket Nos.: 50-369 and 50-370
License Nos.: NPF-9 and NPF-17
Inspection Conducted:
December 21, 1985 - January 27, 1986
Inspectors: b.
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N/k[
W. Orders ~, SenTor fdent Jfisptor
(Tate Signed
8 W0mo- J w'
._sy/P/M
R. Pfe'rion, Resid
Inspectpf'
fate 41gned
Virgil Sr6wnfte,' Section Chief ( Acting)
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Approved by:
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Ofte Signed
Division of Reactor Projects
SUWARY
Scope: This routine unannounced inspection involved 176 hours0.00204 days <br />0.0489 hours <br />2.910053e-4 weeks <br />6.6968e-5 months <br /> on site in the
areas of operations, surveillance testing and maintenance activities.
Results: Of the three areas inspected, one violation was identified concerning
an inadequate post trip review relative to the reactor trip and safety injection
on unit one of November 2, 1985 (50-369/85-45-01).
8604020538 860324
ADOCK 05000369
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REPORT DETAILS
1.
Persons Contacted
Licensee Employees
- T
McConnell, Plant Manager
- B. Travis, Superintendent of Operations
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- D. Rains, Superintendent of Maintenance
- B. Hamilton, Superintendent of Technical Services
L. Weaver, Superintendent of Administration
- M. Sample, Superintendent of Integrated Scheduling
- E. McCraw, License and Compliance Engineer
- D. Mendezoff, License and Compliance Engineer
- D. Marquis, Performance Engineer
R. White, IAE Engineer
- G. Vaughn, General Manager, Nuclear Stations
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~*M. McIntosh, General Manager, Nuclear Support
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- Dr. W. Haller, Manager, Technical Services
- G. Cage, Systems Engineer, General Office Operations
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- M. Geddie, General Office, Nuclear Operations
Other licensee employees contacted included construction craf tsmen, tech-
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nicians, operators, mechanics, security force members, and office personnel.
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- Attended exit interview.
2.
Exit Interview
The inspection scope and findings were summarized on January 31, 1986, with
those persons indicated in paragraph I above. The licensee did not identify
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as proprietary any of the materials provided to or reviewed by the inspectors
during this inspection.
3.
Licensee Action on Previous Enforcement Matters
Previous enforcement matters were not evaluated in this report.
4.
Unresolved Items
Two unresolved items were identified during this report period.
They are
discussed in paragraphs 7 and 8.
5.
Plant Operations
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The inspection staff reviewed plant operations during the report period, to
verify conformance with applicable regulatory requirements.
Control room
logs, shift supervisors logs, shift turnover records and equipment removal
and restoration records were routinely perused.
Interviews were conducted
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with plant operations, maintenance, chemistry, health physics, and perfor-
mance personnel.
~ Activities within the control room were monitored during shifts and at shift
changes. Actions and/or activities observed were conducted as prescribed in
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applicable station administrative directives. The complement of licensed
personnel on each shift met or exceeded the minimum required by technical
specifications.
Plant tours taken during the reporting period included but were not_ limited
to the ~ turbine buildings, auxiliary building, units 1 and 2 electrical
equipment rooms, units 1 and 2 cable spreading rooms, and the station yard
zone inside the protected area.
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During the plant tours, ongoing activities, housekeeping, security, equip-
ment status and radiation control practices were observed.
Unit 1 Operations
McGuire 'Jnit 1 began the reporting period operating at 100% power and
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remained at this power until Sunday December 22 when a reactor trip occurred
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from 100% power. The trip was determined to have been initiated by arcing
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on the 18 generator breaker on the transformer side Y phase motor operated
disconnect. The generator breakers opening caused the turbine to trip on
over speed which subsequently caused the reactor to trip.
All systems
responded normally.
Reactor startup was commenc3d .t 10:00 a.m., on December 23, 1985, with the
reactor reaching criticality at 10:20 a.m.
The unit was placed on line at
2:15 p.m., but was limited to 50% rower pending completion of repairs to
the IB generator breaker.
Follnwing repairs to the generator breaker at
10:57 a.m., on December 24,1985, power was subsequently increased to 100%
power and remained at or about 100% power until 5:31 p.m., January 5,1986,
when a reactor trip / turbine trip occurred on "0" steam generator lo-lo
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level. All systems responded normally.
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During investigation of the reactor trip, it was determined that the "0"
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steam generator feed regulator valve failed closed due to a faulty driver
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card in the 7300 cabinets. This was subsequently repaired and a reactor
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start-up was commenced at 4:45 a.m., on January 6th.
The reactor reached
criticality at 5:04 a.m.,
and the unit went on line at 7:20 that morning.
Power was raised to 100% and the unit remained at or about 100% throughout
the reporting period.
Unit 2 Operations
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McGuire Unit 2 began the reporting period shutdown recovering from an outage
to effect repairs to the D steam generator which is discussed in report
50-369/85-41 and 50-370/85-42.
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Reactor startup was ccmmenced on December 25, 1985, with the reactor reaching
criticality at 2:35 a.m., that morning. The unit was subsequently paralleled
to the gr'd at 4:34 a.m., and power was increased to 100% where it remained
until December 30, 1985, when power was redaced to 15% to effect repairs to
the
"B" Steam Generator feed regulator valve.
Following repairs to this
valve, power was increased to 100% and remained at or about 10W% until
11:49 a.m.,
January 15 when a reactor trip / turbine trip occurred on "A"
steam generator 10-10 level. This trip was precipitated by a load rejection
due to a vacuum trip on "A" condensate feed pump.
All safety systems
responded normally.
A reactor start-up was commenced that evening and the unit reached criti-
cality at 10:15 p.m.,
and entered Mode 1 at 11:16 p.m.
While attempting
to place the main generator on line, #4 Governor Valve was determined to be
Consequently when the unit was placed on line, it was operated
at a reduced power level of 92%.
Following changes in the secondary side
the plant power was increased to 100% with #4 Governor Valve closed and
remained at this power in this condition until January 23, 1986.
At 4:00 a.m., that morning an unidentified leak of 1.5 gallons per minute
was declared. Unit shutdown commenced at 10:00 a.m., and an Unusual Event
was declared. At 1:06 p.m.,
when the unit was still at approximately 10%
power a reactor trip from Intermediate Range High Flux occurred. This trip
is discussed in paragraph 7.
The Unusual Event was terminated when the source of the leak was stopped
at 11:54 a.m.,
on January 24th.
Unit startup subsequently followed and
the unit was critical at 12:54 a.m. , on January 25th. The generator was
paralleled to the grid at 2:25 a.m., and the unit reached 100% that af ter-
noon at 5:00 p.m. , and remained at 100% throughout the reporting period.
The #4 Governor Valve remained closed and inoperable pending repair at the
next refueling outage.
6.
Degraded Pressurizer Heater Group
McGuire Nuclear Station Directive 3.1.10 definas the action to be taken in
investigating reactor trips to ensure full understanding of the cause of the
trip; the plant transient behavior before and af ter the trip; the trip's
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impact on nuclear safety, power production and performance; and to identify
necessary corrective action.
In addition, this directive prescribes the
criteria that must be satisfied in order to restart the unit.
A post-trip review is performed immediately following a reactor trip and
completed prior to restart of the unit.
The purpose of the post-Trip Review is to:
a.
Determine the immediate cause of the reactor trip.
It is not required
that the root cause (e.g., the cause of a component failure leading to
a trip) be determined at this time.
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b.
Identify other-than-expected performance of operators, systems, and
equipment and assess its impact on safe plant operation.
In addition, any deviations from expected behavior are to be investigated in
depth as appropriate.
The Post-Trip Review is performed by the Reactor Engineer with assistance as
needed from other personnel. The results of the review are documented and
provided to personnel performing a subsequent investigation.
Written guidelines are used in performing the Post-Trip Review.
These
guidelines describe the various aspects of the trip event that should be
considered in order to ensure that any impact on safe operation is identi-
fied and resolved.
It also orovides criteria and guidelines defining the
range of expected plant responses.
Prior to restart of the unit. Operations ensures that the following criteria
are met:
a)
The immediate cause of the reactor trip is known or has been investi-
gated to the fullest extent possible while remaining in the shutdown
condition.
b)
The plant transient behavior, immediately preceding and until stabili-
zation following the trip .does not identify any unresolved problems
that impact the ability of the unit to be safely restarted and operated.
c)
Any malfunctions or failure in equipment or components subject to
technical specification LCO requirements are evaluated and corrected as
required prior to restart.
Operations further ensures that the Reactor Engineer's recommendations are
resolved prior to restart and obtains his or her concurrence with restart.
This concurrence is indicated by the Reactor Engineer's signature on the
trip recovery operating procedure.
Additionally, Station Directive 3.1.10 requires that a review of performance
of safety systems be performed in order to identify other than expected
performance. Abnormal behavior requires in depth evaluation and resolution
prior to restart. If performance in all areas was as expected, the unit may
be safely restarted.
In the Post-Trip Review conducted for the reactor trip of November 2, 1985,
discussed in Report 50-369/85-40 and 50-370/85-41. it was noticed in the
list of performance anomalies that one group of heaters in pressurizer
heater bank A was out for 1.5 minutes during the transient.
This was not
evaluated prior to restarting the unit and the reason for the heater failing
was not determined.
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After subsequent questioning by the resident inspection staff, it was
determined that the alarm was not erroneous but was caused by a blown fuse
to one group of heaters in pressurizer heater bank A.
As a result, the
decrease in load caused the current drawn for the remaining banks to be
approximately the same as the alarm setpoint for the pressurizer heater
bank A.
Since the alarm was intermittent the operators and the post trip
reviewing personnel did not realize that it was a problem and did not pursue
it to resolution.
Although the personnel involved with the post trip review, and subsequent
decision to restart the unit, did not feel at the time that there was any
question that the Unit could be safely restarted and operated, it is the
intent of a Post Trip Review to identify potential problems.
In this
particular instance, *he fact that the pressurizer heater bank A was indi-
cating that it was not fully operable should have prompted further investi-
gation prior to reactor startup.
Consequently, during this Post Trip
Review, Station Directive 3.1.10 was not fully implemented, an adequate Post
Reactor Trip Review was not conducted, in that Operations did not ensure
that malfunctions or failure in equipment or components subject to Technical
Specification LCO requirements were evaluated and corrected as required
prior to restart.
Technical Specification 6.8.1 requires that written procedures shall
be established, implemented, and maintained covering the activities
referenced
in
Appendix A
of
Regulatory
Guide
1.33,
Revision 2,
February 1978.
Section 2 of this Appendix requires that General Plant
Operating Procedures be implemented and used for recovery from Reactor Trip.
McGuire Nuclear Plant Operations Procedures specify that an engineering
evaluation be performed prior to entering Mode 2.
This engineering eval-
uation is the Post Trip Review Report performed in accordance with Station
Directive 3.1.10 which states that prior to restart of a unit, Operations
shall ensure specific criteria including the following are met:
(1) The plant transient behavior immediately preceding and until stabill-
zation following the trip, does not identify any unresolved problems
that impact the ability of the unit to be safely restarted and operated.
(2) Any malfunctions or failures in equipment or components subject to
Technical Specification LCO requirements are evaluated and corrected as
required prior to restart.
It further requires, in Enclosure 4.1,
that a review of performance of
safety systems, be performed to identify other than expected performance.
Abnormal behavior requires in-depth evaluation and resolution prior to
restart.
The post trip review for Unit 1 preceding the reactor startup of
November 2,1985, did not evaluate and resolve the abnormal behavior noted
on Pressurizer Heater Bank A prior to restart.
This is a violation
(369/85-45-01).
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7.
Intermediate Range Neutron Detectors
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A reactor trip occurred on January 23, 1986, when unit 2 was at approxi-
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mately 10% power during shutdown following a determination that unidentified
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leakage was about 1.5 gallons per minute. The reactor trip was caused by an
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improperly set intermediate range high flux trip set point. When the P-10
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block permissive value decreasing power re-set point was met the inter-
mediate range high flux trip was unblocked and a reactor trip occurred.
The licensee had replaced the source and intermediate range detectors on
December 18, 1985.
Technicians had determined through troubleshooting
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following implementation of a Nuclear Station Modification (NSM MG-2-496
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Rev. 0 -- changing out existing source range channel N31 and N32 preampli-
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fiers with new low noise pre-amplifiers) that excess noise and ringing were
present.
Replacing the source and intermediate range detectors corrected
this problem.
The unit was in Mode 5 at the time.
The unit was started
up on December 25, 1985, and was operated at or about 100% power until
January 15, when it experienced a reactor trip as discussed in Paragraph 5.
Following this trip the unit was again restarted and operated between 92 and
100% until January 23, when the intermediate range high flux trip occurred
at approximately 10% power during plant shutdown.
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The intermediate range had not been calibrated during this time. Following
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installation, licensee personnel had subjectively determined that the new
detector was more sensitive than the detector it replaced and as result a
channel calibration was not performed and the intermediate low power reactor
set points were not verified. Procedures exist to perform a channel cali-
bration per Technical Specification requirements following core refueling
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or modification.
Procedures to perform a channel calibration following
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intermediate detector replacement do not appear to exist.
Pending the
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completion of the ongoing investigation, this item will be carried as an
Unresolved Item (50-370/85-46-01).
8.
Volume Control Tank Isolation Valves
On January 6,1986, during a review of the circumstances surrounding the
safety injection which occurred on McGuire Unit 1 on November 2,1985, the
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inspector determined that the un.it had been operated in modes where valves
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1-NV-141 and 1-NV-142 were required, with both valves inoperable. Valves
1-NV-141 and 1-NV-142 are the isolation valves of f the Volume Control Tank
(VCT) supplying a common suction to the charging pumps (NV).
The NV pumps
also serve as the high head safety injection pumps. The concerns associated
with operating the unit with valves 141 and 142 inoperable are entailed in
Report 369/86-04.
Detailed herein are concerns associated with why the valve operators for
both valves failed during the aforementioned transient.
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At 6:40 a.m., on Novembrr 2,1985, both valves 141 and 142 closed during
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the safety injection as designed. When terminating the safety injection,
operators were unable to open valves 141 and 142 from the control room, but
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succeeded in manually cranking the valves open locally, thus re-establishing
the normal make-up flow path.
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By 6:00 p.m.,
that evening, it was determined that the motor operator for
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142 had burned up and by 10:00 p.m., it was known that 141 was also burned
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up.
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Efforts to ascertain the facts concerning the failure mode of these operators
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are inconclusive at the end of the report period. For that reason this area
of concern will be carried forward as an Unresolved Item (50-369/85-45-02).
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9.
Surveillance Testing
The surveillance tests categorized below were analyzed and/or witnessed by
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the inspector to verify procedural and performance adequacy and conformance
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with applicable Technical Specifications. The selected tests witnessed were
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examined to ascertain that current written approved procedures were avail-
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able and in use, that test equipment in use was calibrated, that test
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prerequisites were met, system restoration completed and test results were
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adequate.
PT/0/A/4350/11
Reactor Coolant Pump Undervoltage and Underfrequency
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Functional Test
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PT/1/A/4208/01A
Containment Spray Pump 1A Performance Test
PT/1/A/4208/01B
Containment Spray Pump 1B Performance Test
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PT/1/A/4208/03A
Containment Spray Heat Exchanger Performance Test
PT/1/A/4252/01A
CA Pump 1A Performance Test
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PT/1/A/4252/018
CA Pump 1B Performance Test
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PT/1/A/4252/01
Turbine Driven CA Pump Test
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PT/1/A/4401/01A
KC Pump 1A Performance Test
PT/2/A/4206/12
UHI Valve Stroke Timing Test
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PT/2/A/4206/01A
NI Pump 2A Performance Test
PT/2/A/4601/07A
Reactor Trip Breakers Response Time Testing
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PT/2/A/4601/08A
SSPS Train A
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PT/2/A/4252/01A
CA Pump 2A Performance Test
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PT/2/A/4252/01B
CA Pump 2B Performance Test
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PT/2/A/4252/01
Turbine Driven CA Pump Test
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10. Maintenance Observations
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The maintenance activities categorized below were analyzed and/or witnessed
by the resident inspection staff to ascertain procedural and performance
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adequacy and conformance with applicable Technical Specifications.
The
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selected activities witnessed were examined to ascertain that where
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applicable, current written approved procedures were available and in use,
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that prerequisites were met, equipment restoration completed and maintenance
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results were adequate.
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93725 IAE.
Implement NSM MG-2-496 Rev. 0
65534 IAE
Repair Pressurizer Heater Group B
11. Open Items Review
The following items were reviewed in order to determine the adequacy of
corrective actions, the implications as they pertain to safety of opera-
tions, the applicable reporting requirements, and licensee review of the
event.
Based upon the results of this review, the items are herewith
closed.
50-369
LER 85-27
LER 85-28
50-370
LER 85-36