ML20135A440
| ML20135A440 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 11/26/1996 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20135A422 | List: |
| References | |
| 50-373-96-10, 50-374-96-10, NUDOCS 9612030222 | |
| Download: ML20135A440 (11) | |
See also: IR 05000373/1996010
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U.S. NUCLEAR REGULATORY COMMISSION
REGION 111
Docket No:
50-373, 50-374
License No:
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Report No:
50-373/96010, 50-374/96010
Licensee:
Commonwealth Edison Company
Facility:
LaSalle County Station, Units 1 and 2
Location:
2601 N. 21st Road
Marseilles, IL 61341
Dates:
August 3 - September 13, 1996
Inspectors:
M. Huber, Senior Resident Inspector
K. Ihnen, Resident Inspector
H. Simons, Resident Inspector
J. Roman, Illinois Department of Nuclear Safety
Approved by:
Bruce Jorgensen, Acting Chief
Reactor Projects Branch 5
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9612030222 961126
ADOCK 05000373
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EXECUTIVE SUMMARY
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LaSalle County Station, Units 1 and 2
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NRC Inspection Report 50-373/96010; 50-374/96010(DRP)
This inspection report included aspects of licensee operations, maintenance,
engineering and plant support. The report covers a 6-week period of
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inspection conducted by the resident inspectors.
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Plant Operations
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Comed took good initiative to perform a review of their Technical
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Specification (TS) interpretations. However, they found that 17 of 43
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interpretations were not fully compatible with the licensing or design
basis of the plant.
The licensee initiated corrective actions including
upgrading their process for review and approval of TS interpretations.
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Maintenance
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Materiel condition problems continued to challenge the operations,
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maintenance, and engineering organizations.
Emergent equipment problems
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resulted in difficulties for the maintenance organization in
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accomplishing scheduled work. These problems challenged operations in
that, in several cases, the plant was placed in short-duration limiting
conditions for operations.
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Enaineerina
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The conduct of root cause analyses for both the 0 diesel generator (DG)
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output breaker failure and reactor core isolation cooling (RCIC) rupture
disc event were weak.
In both cases, the root cause team made non-
conservative recommendations to the plant operations review committee
(PORC) regarding the operation of plant equipment.
In one case, they
recommended bypassing a protective relay on the DG.
In the RCIC event,
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they recommended preconditioning the plant equipment.
In both cases,
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PORC performed their function and did not approve the root cause team
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recommendations.
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ReportDetails
Summary of Plant Status
Unit 1 operated at or near full power for the entire inspection period.
Unit 2 entered the period at 96% power, derated because of thermal limit
concerns due to power suppression in the area of two previously identified
leaking fuel assemblies. On August 18, 1996, main turbine control valve (TCV)
- 2 partially closed and then reopened. The valve position continued to
oscillate.
The decision was made to close the valve and limit power to 83%.
The unit operated at the reduced power for the remainder of the period.
I.
Doerations
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Conduct of Operations
01.1 General Comments (71707)
The inspectors conducted frequent reviews of ongoing plant operations.
Walkdowns were performed in the main control room, emergency diesel
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generator rooms, auxiliary electrical equipment rooms, safety related
pump rooms, the reactor building, and the turbine building. The
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inspectors also discussed plant status and pending evolutions with shift
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personnel in the control room.
01.2 Shift Operatina Activities
a. Insoection Scope
On several occasions, the operating shift was required to respond to
indications of equipment performance problems.
For each event, the
inspector reviewed the symptoms, causes and consequences, along with
licensee response and decisionmaking.
On August 8, Operations identified that the lake makeup line was not
supplying makeup water as designed. A search revealed a break in this
5-mile concrete supply pipe approximately a mile from its source at the
Illinois river.
Repairs to the makeup line were pursued on a high-
priority basis, to ensure the absence of lake makeup would not impact
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adversely on the cooling lake, particularly on the capability to
maintain level in the ultimate heat sink well above the necessary
minimum.
On August 18, the #2 turbine control valve (TCV) on the Unit 2 main
turbine unexpectedly closed.
It immediately re-opened. Operations had
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done nothing to precipitate the erratic TCV behavior, so they
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immediately focused closely on this valve.
Small oscillations continued
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to occur, leading to a decision to manually close the valve and keep it
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closed. This decision resulted in a need to reduce reactor power to
about 83% of full power for the last several weeks of the plant
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operating cycle leading up to a scheduled refueling outage. The
decision provided protection from TCV-induced transients and was
considered prudent by the inspectors.
The shared, "0" emergency diesel-generator was found to have a failed-
open backwash valve during a routine operator round on September 6,
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1996. This led operations to declare the diesel-generator inoperable
and enter a 72-hour LCO. The inspector received the circumstances and
found the licensee correctly applied the LCO.
On September 7, operations encountered difficulty in maintaining the
required reactor building differential pressure.
Prompt diagnosis of
the problem indicated the control system was malfunctioning, so the
operators decided to switch the ventilation system to manual control.
The inspector noted good coordination with engineering in the
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installation of a temporary alteration to provide manual control
capability. This restored differential pressure to the required level.
In addition, the inspector verified that the correct LC0 was applied.
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b. Conclusions
Operations correctly diagnosed the problems encountered and applied the
correct Limiting Condition for Operation or other prudent control to
successfully overcome each difficulty.
Coordination with maintenance
and/or engineering was good.
01.3 Licensee Review of Technical Soecification (TS) Clarifications
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a. Inspection Scope (71707)
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The inspectors reviewed the licensee's efforts to verify that the TS
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clarifications written by the licensee conform to the current licensing
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and design basis of the plant. The inspector discussed several of these
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clarifications with the licensee staff and attended the Plant Operations
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Review Committee (PORC) meeting which reviewed the issue.
b. Observations and Findinas
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Comed assigned a review team to conduct a complete review of their TS
clarifications. These clarifications were written interpretations
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provided to the control room personnel to assist in interpreting TSs.
There were a total of 43 TS clarifications. The review team determined
that 17 of the TS clarifications were not compatible with the current
licensing or design basis.
Fourteen of the 43 clarifications were in
accordance with the licensing and design basis; however, the safety
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evaluations associated with these clarifications had been performed
several years ago and the quality was not in accordance with Comed's
current standards. As a result, the licensee decided to re-perform the
50.59 evaluations and have the PORC review the upgraded 50.59s. Seven
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of the 43 clarifications were determined to be valid; however, the
licensee determined that these clarifications should be controlled via
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other administrative methods such as in procedures. The safety
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evaluations for these clarifications will be reviewed by PORC as the
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clarifications are moved to other administrative controls.
Five of the
43 were determined to be acceptable by the review team with respect to
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the licensing and design basis, and they had an appropriate safety
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evaluation. These five clarifications were retained with no further
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actions.
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The problems with the TS clarifications were discussed at a PORC meeting
on August 30, 1996. The PORC decided to cancel the 17 questionable
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clarifications and approve the five clarifications that the review team
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identified as meeting the design and licensing basis. The other
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clarifications and the upgraded safety evaluations will be reviewed by
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PORC at a later date.
In addition to initiating corrective actions to
address the immediate concerns identified by the TS interpretation
reviews, the licensee initiated corrective actions to upgrade their
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process for review and approval of TS clarifications.
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At.the end of the inspection period, the licensee was reviewing the
clarifications that were canceled to evaluate if there were any events
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involving these clarifications that were required to be reported in
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accordance with 10 CFR 50.72 and 50.73.
c. Conclusion
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Comed took good initiative to perform a review of their TS
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interpretations, and the review criteria and depth were of good quality,
iiowever, they found that 17 of 43 interpretations were not compatible
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with the licensing or design basis of the plant. The licensee has
initiated corrective actions including upgrading their. process for
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review and approval. of TS interpretations. The licensee's initial
review determined that a Licensee Event Report (LER) would be required.
The inspectors will follow this issue through the LER.
II.
Maintenance-
M1
Conduct of Maintenance
The inspectors observed several maintenance and surveillance activities
during this inspection period in accordance with inspection procedure
62703 and 61726.
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M1.1 Routine Activities
a. Insoection Scone (62703. 61726)
The inspectors observed routine (typically, monthly) maintenance and
surveillance activities as they were being performed or conducted in the
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plant and discussed the activities with the personnel performing them.
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b. Observations and Findinas
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The routine surveillance of emergency diesel generator IA was observed
and reviewed against criteria established in the UFSAR, the technical
specifications and the controlling test procedure.
The personnel-
performing the test were closely following the test procedure.
Communications and coordination among involved personnel were good. The
test results met all the required criteria.
Surveillance testing of the Unit I standby gas Treatment system was
observed in detail. The inspector reviewed the applicable procedure,
technical specifications and UFSAR information and discussed system
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performance with personnel conducting the test.
Knowledge and
understanding of the involved personnel were good; the test was
successfully completed in conformance to all specified performance
criteria.
c Conclusions
Routine test activities were successfully performed in accordance with
applicable controls by personnel who were knowledgeable and who
coordinated their activities well. No significant problems were
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observed in the conduct of these activities.
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M2
Maintenance and Material condition of Facilities and Equipment
M2.1 Materiel Condition Continued to Impact Operation and Scheduled Work
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a. Insoection ScoDe (71707. 62703)
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The inspectors followed the daily scheduled work and emergent
equipment problems to assess materiel condition.
b. Observations and Findinas
As noted above, during this inspection, several equipment failures
occurred which continued to challenge operations and affect the conduct
of scheduled work.
For example, operations identified that there was a break in the lake
makeup line on August 8, 1996. The lake makeup line is a 5-mile stretch
of concrete pipe which connects the LaSalle cooling lake (ultimate heat
sink) to the Illinois River. As a result of this failure, significant
engineering and mechanical maintenance resources were diverted to repair
the line. The licensee has experienced previous breaks of the lake
makeup line. The inspectors periodically monitored the work activities
associated with this job. The work was completed in good time to ensure
the cooling lake and the ultimate heat sink always had more than
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adequate water level.
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On September 6,1996, the licensee identified', during a system walkdown,
that the backwash valve on the 0 DG cooling water strainer had failed
open with a potential stem to disc separation. The 0 DG was declared
inoperable and a 72-hour Limiting Condition for Operation (LCO) was
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entered. The' resultant emergent work challenged the operations,
maintenance, and engineering departments. The inspector observed work,
monitored progress and schedule and followed return-to-service
activities. Although challenging,' the work was properly completed
within the limits of the LCO.
On September 7,1996, operations experienced problems with the reactor
building differential pressure. - A temporary alteration was installed to
operate the reactor building ventilation manually such that
troubleshooting could be done on the control system where the problem
apparently originated. The problem was traced to a failed controller.
This problem challenged operations by placing them in a 4-hour LCO for
secondary containment and it also challenged the maintenance
organization because of its emergent nature. The inspector reviewed the
activity and the control system history, and found the work was
completed properly and in compliance with LCO requirements.
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c. Conclusion
Materiel condition problems continued to challenge the operations,
maintenance, and engineering organizations.
Emergent equipment problems
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were handled successfully, but they resulted in difficulties for the
maintenance organization to. accomplish scheduled work and caused the
engineering organization to focus on reactive rather than proactive
activities. These problems also' challenged operations in that, in
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several cases, the plant was placed in short duration LCOs.
In each
case, LC0 requirements were met.
III.
Enaineerina
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Conduct of Engineering
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El.1 Enaineerina Root Cause Analysis of 0 DG Failure
a. Scone (37551)
The inspectors observed the troubleshooting activities for the 0 DG
after the output breaker for Unit I failed to close during surveillance
testing following maintenance. The inspectors also observed the root
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cause analysis effort.
b. 0bservations and Findinas
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On August 14, 1996, the 0 DG was being run in accordance with LOS-DG-M1,
"O Diesel Generator Operability Test," Revision 31, when the output
breaker failed to close on Unit 1.
Operations personnel notified system
engineering and maintenance of the problem.
The initial troubleshooting was not performed using the available
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procedure. The purpose of LTP-500-1, " Diesel Generator Output Breaker
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Troubleshooting Procedure," Revision 6, as stated in the procedure, is
to determine the failure mode in the event that a DG output breaker
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fails to close during its monthly operability surveillance.
The system
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engineer and electrician did not use this procedure; instead they
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performed troubleshooting based on their personal knowledge using a
controlled electrical print. The system engineer and electrician were
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unaware that LTP-500-1 existed. This failure to follow procedures is a
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violation of 10 CFR 50, Appendix B, Criterion V (VIO 373;374/96010-01).
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As a result, the troubleshooting w'as not well documented. The next day
most of the initial troubleshooting had to be re-performed because of
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the uncertainty of the tests that had already been conducted. At that
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time, there were only about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> left of the 72-hour LCO.
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While the troubleshooting was taking place, a root cause team assembled
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to assist in identifying the root cause. This team became narrowly
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focused on one component during the troubleshooting activities. The
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team was focused on the synchronization check (HACR) relay as the root
cause, partly due to past equipment problems with this relay. This
relay provides a protective function when paralleled with an outside
source in that it requires the DG to be in-phase in order to close the
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output breaker.
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The root cause team recommended jumpering out the relay even though
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there were spare calibrated relays onsite. Also, by early afternoon on
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August 15, troubleshooting had ruled out the possibility of a problem
with the HACR relay.
Even after troubleshooting ruled out the HACR
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relay as the cause, the root cause team took a procedure change to the-
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PORC for approval. This procedure change allowed jumpering out the HACR
relay. The PORC made the good decision to disapproved the proposed
procedure change.
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Further troubleshooting identified a failed component in the starting
circuitry, specifically, the interposing relay. This component was
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replaced and the DG was tested satisfactorily.
c. Conclusigni
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The PORC decision was a good decision, because the root cause team did
not present a' valid reason for needing the procedure.
In addition, it
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was viewed as a non-conservative action to bypass the DG's protective
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equipment.
El.2 Enaineerina Root Cause Analysis of Reactor Core Isolation Coolina (RCIC)
Ruoture Disc Event
a. Scope (37551)
The inspectors reviewed the licensee's root cause analysis efforts,
maintenance recovery efforts, and management involvement in the RCIC
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rupture disc event.
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b. Observations and Findinas
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On August 19, 1996, while performing LOS-RI-Q5, " Reactor Core Isolation
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Cooling (RCIC) System Pump Operability, Valve Inservice Tests in
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Conditions 1, 2, 3, and Cold Quick Start," Revision 8,,on Unit 1, the
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RCIC exhaust line rupture discs blew. No one was injured or
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contaminated. The licensee immediately began a root cause
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investigation.
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The licensee determined that the most likely cause of the rupture disc
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failure was plugging of the steam. drain line causing water to collect
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in the exhaust.line and turbine casing. When RCIC'was started for the
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monthly run, the water in the turbine casing was displaced downstream to
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the drain pot where this excessive water created a loop seal and
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overpressure condition. As a result, the rupture discs-blew. The
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licensee determined that the most probable cause for the water in the
exhaust drain line was a marginal drain line design such that the drain
line was unable to pass expected corrosion products or foreign material.
When the licensee inspected _the drain line piping, they did not find any
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significant amount of corrosion products or foreign material. The
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licensee assumed the overpressure condition cleared any obstruction of
the drain line.
Overall, the root cause effort was unorganized with weak management
oversight. There was a disconnect between the root cause team,
management, and the workers in the field. As a result of this
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disconnect,' the root cause analysis and repair work did not proceed
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smoothly. Over 12 problem identification forms were generated during
the repair of the rupture discs. On day 10 of the 14-day LCO, the
Maintenance Superintendent stopped all work on RCIC because of the
disorganization of the recovery efforts.
Finally, the repair work was
completed on day 13 of the 14. day LCO.
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The root cause report was not final at the end of this inspection
period.
However, the inspectors attended the PORC meeting on August 30,
1996, where the root cause team presented their preliminary root cause
and short term corrective actions. The root cause team presentation to
PORC was largely administrative until the members of the PORC began
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asking detailed technical questions and challenging the conclusions of
the root cause team. The' root cause team was unable to answer many
technical questions to support the bases for their' conclusions. The
root cause team was not completely forthcoming in their discussions; for
example, when discussing the long term corrective actions from the
previous RCIC rupture disc event in 1994, they were very non-specific
about whether or not all the long term corrective actions had been
implemented.
The. root cause team's recommendations for immediate corrective actions
were considered weak. One of the immediate corrective actions was to
put a drain line on the drain pot such that the drain pot could be
manually checked for water. The root cause team recommended only
checking this drain line before and after scheduled RCIC runs. The
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Operations Manager, a member of the PORC, quickly questioned the root
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- cause team on the acceptability of this practice and whether it was
preconditioning.
The root cause team did not view this as preconditioning as they felt
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the first action to take if water was found would be to declare RCIC
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However, the PORC asked the root cause team to re-evaluate
the frequency at which the drain line should be checked.
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Another corrective action was to put a strainer in the drain line to
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catch any foreign material which could potentially clog the downstream
orifice. The root cause team recommended that this strainer be checked
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every refueling cycle. However, they could not present any basis for
this. The PORC asked that they also re-evaluate the frequency of this
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activity.
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This PORC meeting lasted approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and the PORC members
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asked the root cause team to re-evaluate specific recommendations and
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reconvene the PORC to discuss specific actions. The PORC reconvened the
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next day, August 31, to discuss these issues; however, no one from the
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root cause team was at the PORC to present the additional information.
The PORC relied on the system engineer to make the presentation although
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this was not his responsibility as he was not a member of the root cause
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team.
The PORC members again asked technical questions which could not
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be answered. As a result, the PORC made decisions and solved the
problems rather-than maintaining an oversight function.
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The inspectors will track the final corrective actions for the RCIC
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rupture disc event as an Unresolved Item (URI 373;374/96010-02).
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to be reviewed by the inspector prior to closure include:
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the final root cause report,
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work packages associated with the repair of the rupture
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disc, and
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implementation of corrective actions from the 1994 rupture
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disc event.
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El.3 Conclusions on the Conduct of Root Cause Analyses
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The root cause analyses conducted for.both the 0 DG and RCIC events were
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weak in that the root cause teams were either narrowly focused or
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unorganized.
In both cases, the root cause team made non-conservative
recommendations to the PORC regarding the operation of plant equipment.
In one case, they recommend bypassing a protective relay on the DG,
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the RCIC event, they recommended preconditioning' plant equipment.
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both cases, PORC performed their function and did not approve the root
cause team recommendations.
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IV.
Plant Support
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The inspectors reviewed plant support activities in accordance with inspection
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procedure 71750 as part of their daily inspections. These activities included
verifying plant personnel were complying with radiological protection
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procedures, observing the ALARA principle, and generally knowledgeable of
plant conditions.
No problems were observed in the areas of radiation
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protection, security, or emergency preparedness.
V.
Manaaement Meetinas
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Exit Meeting Summary
The inspectors presented the results of these inspections to Comed
management at an exit meeting on September 13, 1996.
Comed acknowledged
the findings presented.
The inspectors asked the licensee if any materials examined during the
inspection should be considered proprietary
No proprietary information
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was identified.
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PARTIAL LIST OF PERSONS CONTACTED
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- W. Subalusky, Site Vice President
- D. Ray, Station Manager
- L. Guthrie, Operations Manager
- A. Magnafici, Acting Maintenance Superintendent
R. Fairbank, System Engineering Supervisor
- P. Antonopoulos, Site Engineering Manager
D. Boone, Health Physics Supervisor
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- R. Crawford, Work Control Superintendent
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J. Burns, Regulatory Assurance Supervisor
- Present at evit meeting on September 13, 1996.
INSPECTION PROCEDURES USED
Onsite Engineering
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Effectiveness of Licensee Controls in Identifying, Resolving, and
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Preventing Problems
Surveillance Observation
Maintenance Observation
Plant Operations
Plant Support Activities
ITEMS OPENED,~ CLOSED, AND DISCUSSED
Opened
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373;374/96010-01 VIO
Failure to follow a troubleshooting procedure
373;374/96010-02 URI
Followup of the root cause of the RCIC rupture disc
failure
LIST OF ACRONYMS USED
ALARA As Low As Reasonably Achievable
Diesel Generator
Division of Reactor Projects
Division of Reactor Safety
IDNS Illinois Department of Nuclear Safety
IR
Inspection Report
IFI
Inspection Follow-up Item
LC0
Limiting Condition for Operation
LER
Licensee Event Report
LaSalle Operating Procedure
NRC
Nuclear Regulatory Commission
Problem Identification Form
PORC Plant Operations Review Committee
NRC Public Document Room
RCIC Reactor Core Isolation Cooling System
Turbine Control Valve
TS
Technical Specification
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