ML20059B552
| ML20059B552 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 12/29/1993 |
| From: | Gagliardo J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20059B506 | List: |
| References | |
| 50-298-93-26, NUDOCS 9401040182 | |
| Download: ML20059B552 (10) | |
See also: IR 05000298/1993026
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APPENDIX B
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Inspection Report:
50-298/93-26
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Operating License:
Licensee:
Nebraska Public Power District
P.O. Box 499
Columbus, Nebraska
facility Name:
Cooper Nuclear Station
Inspection At:
Brownville, Nebraska
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Inspection Conducted:
October 10 through November 20, 1993
Inspectors:
R. A. Kopriva, Senior Resident Inspector
W. C. Walker, Resident Inspector
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Approved:
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7.(E.Gapiardo,_ Chief,ProjectSectionC
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Inspection Summary
Areas Inspected: Routine, announced inspection of onsite response to events
and operational safety verification. Also during this inspection period, the
NRC performed an Operational Safety Team Inspection (50-298/93-202) during the
weeks of November I and 15, 1993, and the resident inspectors performed
special inspection (50-298/93-28).
Results:
The licensee identified that weak control of insulation practices on
nonsafety-related components during the 1993 outage apparently led to
the failure of Reactor Water Cleanup Pump B.
The licensee also
identified that incorrect insulation of Reactor Water Cleanup Pump A,
performed under Maintenance Work Request 91-0478, caused overheating and
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subsequent pump failure (Section 2.1).
A reactor _ water cleanup pump preventive maintenance oil sample that was
visually anomalous, was not documented in a deficiency report and the
sample was not analyzed. The pump then failed when placed into service.
The failure to analyze anomalous oil samples is a significant weakness
in the licensee's predictive maintenance activities (Section 2.1).
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9401040182 931229
PDR .ADOCK 05000298
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Planned maintenance and postmaintenance activities for Fire Door H-305
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did not address that the scope of work affected the control room
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envelope.
Consequently, the licensee did not identify that the control.
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room envelope had been rendered inoperable during the maintenance
activity.
It was also difficult to determine the extent and nature of
maintenance activities performed on fire doors by the documentation
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provided in the maintenance work requests.
This issue is a violation
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(Section 2.2).
Prejob planning.for work on the cracked condensate drain line in the
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feedwater heater room and the radiological prebrief was excellent
(Section 2.3).
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The licensee's housekeeping efforts in the reactor building resulted in
perceptible improvement (Section 3.2).
Fire watches posted as compensatory measures were knowledgeable of their
responsibilities as fire watches and the actions they would take in the
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event a fire occurred (Section 3.3).
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Summary of Inspection Findings:
Unresolved Item 298/9326-001 was opened (Section 2.1)
V' elation 298/9326-002 was opened (Section 2.2)
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Attachment:
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Attachment - Persons Contacted and Exit Meeting
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DETAILS
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1 PLANT STATUS
The plant was operated at essentially 100 percent power throughout this
inspection period.
Routine minor power reductions were performed to
facilitate control rod operability testing and turbine testing.
On
October 16, 1993, reactor power was dropped to approximately 55 percent to
investigate a small leak on a condensate drain line inside'the feedwater
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heater bay. On November 3, reactor power was dropped again to approximately
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55 percent for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to effect the repair of the leaking condensate drain
line.
The plant was restored to 100 percent power following completion of the
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repairs on Navember 3.
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2 ONSITE RESPONSE TO EVENTS (93702)
2.1 Reactor Water Cleanup Pump Failures
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Inspectors reviewed the licensee's response and determination of the causes of
two reactor water cleanup (RWCU) pump failures.
RWCU Pump A failed on
October 21, 1993. The licensee documented the failure in Deficiency
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Report 93-466 and concluded that the failure was due to high heat caused by
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incorrect insulation of the pump.
Pump A-had been rebuilt under Maintenance
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Work Request 91-0478 and had been operational since January 1991.
When Pump A failed, RWCU Pump B was placed in service and locked up on
October 28, after one week of operation.
Pump B had been caution tagged on
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September 23 due to discolored oil and visual copper-colored flakes in the
lubricating oil. The caution tag was hung based on visual observation of oil
samples that were taken as part of-the preventive maintenance program.
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Inspectors reviewed the licensee's corrective actions. At the.end of this
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inspection period, the licensee had not written a deficiency report
documenting the discolored oil. Licensee representatives stated'that they had
not identified the need for a deficiency report. The licensee had not been
sending oil samples that were contaminated with radioactive material, drawn
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under the preventive maintenance program, to a laboratory for analysis because
the licensee did not have the services of a laboratory capable of analyzing
oil contaminated with radioactive material. At the conclusion of this
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inspection, the licensee had not completed their review to identify other
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safety-related systems for which the analysis specified in the predictive
maintenance program had not been completed.
The inspectors will review the licensee's lubricating oil samples analysis '
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program implementation as an unresolved item (298/9326-001).
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The licensee investigated the failure of Pump B under Deficiency Report 93-481
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and made a preliminary determination that the insulation added around the
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pump, during the last refueling outage, had caused excessive heat buildup, _
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which caused Pump B to fail. The insulation was added under Contract E71-9 to
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attempt to lower ambient air temperatures in the room. The RWCU pumps were
not previously insulated and the licensee had not reviewed the effects of the
insulation on the RWCU pumps.
Following the determination that improper insulation had caused or contributed
to RWCU Pump B failure, the licensee issued Deficiency Report 93-522.
Engineering personnel performed.walkdowns of other systems, which revealed
discrepancies with respect to existing insulation configurations when compared
to the E71-9 specifications. The licensee found that discrepancies were minor
in nature, however, the licensee's Nuclear Engineering Department was tasked
with performing a complete analysis to ensure acceptability.
The adequacy of the actions taken by the licensee to identify other possible
insulation deficiencies and to evaluate the afects of any identified
deficiencies will be reviewed based on the identification of this issue in the
Operational Safety Team Inspection Report 50-298/93-202.
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2.2 Failure to Maintain Positive Pressure During Performance of Control Room
Envelope Pressurization Test
On November 19, 1993, with the plant operating at full power, while performing
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the control room envelope pressurization test, positive pressure could not be
maintained in the cable spreading room, as required by the test procedure,
because of leakage past Fire Door H-305.
The control room emergency
ventilation system was declared inoperable at 5:20 p.m., and the shift
supervisor reported the event to the NRC headquarters operations officer at
7:15 p.m., as required by 10 CFR Part 50.7E. Technical Specifications allow
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plant operation for 7 days with the control room emergency ventilation system
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The inspectors reviewed the event and its apparent causes. On November 16,
Maintenance Work Request (MWR) 4068 was written to perform fire protection
inmections and any needed corrective actions on several fire door's, including
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Door H-305. On November 18, maintenance apparently was performed on
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Door H-305 (Lithough this was not documented in the work completed section of
the MWR), which was completely removed from its hinges so maintenance
technicians could shim the door.
Postmaintenance testing for fire protection
purposes was performed on November 19 and engineering personnel present during
the testing of the door noticed that the gap at the top of the door, between
the door and door frame, appeared to have increased to greater than the-
1/8-inch acceptance criteria.
Engineering personnel recommended that the
shif t supervisor perform the control room pressurization test to ensure that
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the maintenance activity had not degraded the control room ventilation
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envelope.
Upon performing the pressurization test, the cable spreading room,
which was included within the control room envelope, did not pressurize.
Nonconformance Report 93-246 was written to document this event and ensure
that corrective actions were taken. The licensee repaired the door again
(MWR-4109) and satisfactorily tested the door on November 20.
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Inspectors found that MWR-4068 did not address the potential effects of door
maintenance on the control room envelope.
Consequently, the specified
postmaintenance testing did not test the control room envelope and, when the
shift supervisor approved MWR-4068 for work on November 16, he did not
recognize that the control room envelope was affected.
Fire Door H-305 was
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completely removed on November 18 by approved maintenance activities, but the
licensee did not know that the control room envelope was rendered inoperable.
The shift supervisor failed to follow Step 4.3 of Procedure 7.0.1.1,
" Maintenance Work Request - Work Item Tracking Form Initiation and Review", in
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that, during a review of WIT Form 93-4068, he did not identify the operability
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issue of control room envelope when work was to be performed on Fire
Door H-305. Also, from November 18-19, the shift supervisors failed to follow
Step 4.12 of Procedure 7.0.1.2, " Maintenance Wrk Request-MWR Generation and
Review," in that all activities relating to station operation and safety
during their shifts were not accomplished because Fire Door H-305 was worked
on and removed without consideration of operability of the control room
envelope. The failure to comply with the requirements specified in these
procedures is a violation of Criterion V of Appendix B to 10 CFR Part 50
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(298/9326-002).
This event also demonstrated significant weakness in the maintenance planning
process. Those responsible for preparing the work documents had apparently
failed to evaluate the impact that this work would have on the plant and,
therefore, failed to provide the first line of defense against performing
maintenance that resulted in the breach of the control room envelope.
At the conclusion of this inspection period, the licensee's review of this
event was in progress. The licensee planned to determine the root cause and
document the findings in a licensee event report to be issued on or around
December 20, 1993. The inspectors will review the licensee event report for
closure at that time.
2.3 Repair of Feedwater Heater Condensate Drain Line
On October 18, 1993, a small crack approximately 1/2 to 3/4 inches long was
identified in the B5 to B4 Condensate Drain Line. The licensee initiated
Deficiency Report 93-462 to document the leak and ensure that a proper root
cause was determined. The licensee indicated that a similar condition in
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close proximity to the present leak had previously occurred. The licensee
requested the Nuclear Engineering Design group to perform an in-depth analysis
of this section of pipe in view of the fact that several previot.s gasket leaks
and two separate cracks in the B5 to B4 condensate drain pipe weld had
occurred.
On November 3, the inspectors observed the temporary repair of the leak. The
repair of the leak was done under MWR 93-3248 and Plant Temporary
Modification 93-61.
The repair consisted of installing a strong back between
the 14- to 10-inch reducer section of piping to prevent pipe separation in the
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event the 3/4 inch crack propagated to full circumference. The inspectors
concluded that the work was well coordinated and organized.
Due to interference problems, technicians were able to install only three of
the four studs, upon which design calculations were based, to connect the
strong back to the end plates.
The licensee then performed an engineering
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analysis that concluded that the three-stud configuration was acceptable. The
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inspectors reviewed the engineering evaluation that addressed the adequacy of
the strong back and the associated items used to prevent pipe separation and
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concluded that the evaluation was adequate.
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The inspectors observed the licensee's prejob briefing, which stressed the
importance of performing their job duties in a safe and prudent manner.
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briefing provided by the radiological supervisor was informative and allowed a
free exchange of information between the workers and radiological protection
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personnel.
The inspectors concluded that the briefing was thorough and
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included radiation protection personnel discussing possible scenarios that
could require emergency evacuation of the work area. Also during performance
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of the work, a health physics technician was in the work area to provide
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radiological oversight of the activities. The licensee reduced reactor power
to lower radiation dose rates in the work area. The inspectors concluded that
the preplanning, the radiological prebrief, and the ALARA considerations taken
by the licensee were excellent.
2.4 Reactor Recirculation Motor-Generator Set Repairs
On October 17, 1993, maintenance technicians performed repairs under
MWR 93-3757.
The B Reactor Recirculation Motor-Generator (MG) Set oil supply
line to the low pressure indicator Switch RRLO-PS-28, was leaking. The brass
tube adapter to the female fitting had cracked. Deficiency Report 93-472 was
written to. document this finding and a root cause determination was performed.
Preliminary findings indicated the failure appeared to be vibration induced.
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The licensee performed a walkdown of the reactor recirculation lube oil
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switches on both MG sets. Twelve additional pressure switches with similar
configurations were observed and three of them had oil leaks. The licensee
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planned to replace the brass tube adapters and the Swagelok unions on all
twelve switches with stainless steel fittings. During discussions with the
vendor of the fittings, the licensee verified that stainless fittings were
inherently more rugged than the brass fittings.
In addition to the above, the
licensee planned to walkdown several other systems throughout the plant to
identify whether similar configurations exist.
Systems identified for
inspections were reactor feedwater, main condensate, turbine generator, lube
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oil, and station / instrument air. Safety-related systems were not included
since these systems were constructed with stainless steel components.
2.5 Diesel Generators Inoperable Due To Problem With Permissive Relay
On November 8, 1993, the inspectors observed the licensee performing
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Surveillance Procedure 6.3.12.1, " Diesel Generator Monthly Operability Test,"
for Emergency Diesel Generator (EDG) 1.
The procedure had been revised on
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November 4 to add an acceptance test of the DG-REL-DG 1 relay. The additional
surveillance requirement was to verify the generator voltage permissive signal
to' the generator output breaker by verifying the continuity of the relay
contacts. The procedure had been revised because the relay setting had been
found out-of-tolerance in April 1993, during the refueling outage.
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At 8:46 a.m., the EDG 1 failed the acceptance test for continuity on
DG-REL-DG 1 relay. The licensee declared EDG 1 inoperable and commenced an
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inspection of the relay.
Because of similar concerns for EDG 2, the licensee
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performed Surveillance Procedure 6.3.12.1.1 for EDG 2.
At 12:02 p.m., EDG 2
failed its acceptance test of DG-REL-DG 2 relay performance and EDG 2 was
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declared inoperable.
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This placed the licensee in an unusual event per their Emergency Action
Level 4.1.2, " Loss Of Both Onsite. Emergency Diesel Generators, But Offsite
Power Is Still Available." NRC Special Inspection Report 50-298/93-28 was
initiated to document the review of the event.
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2.6 Concluelons
The licensee identified that weak control of insulation practices on
nonsafety-related components, during the 1993 outage, apparently led to the
failure of RWCU Pump B.
The licensee also identified that incorrect'
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insulation of RWCU Pump A, performed under MWR 91-0478, caused overheating and
subsequent pump failure.
A RWCU pump preventive maintenance oil sample that was visually ancmalous was
not documented in a deficiency report and the sample was not analyzed. The
pump then failed when placed into service. The failure to analyze anomalous
oil samples is an apparent significant weakness in the licensee's preventive
maintenance activities.
Planned maintenance and postmaintenance activities for Fire Door H-305 did not
address that the scope of work affected the control room envelope.
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Consequently, the licensee did not known that the control room envelope had
been rendered inoperable during the maintenance activity.
It was also
difficult to determine the extent and nature of maintenance activities
performed on fire doors by the documentation provided in the maintenance work
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requests.
Prejob planning for work on the cracked condensate drain line in the feedwater
heater room and the radiological prebrief provided were excellent.
The inspectors found that plant engineering performed a generic review of'
fitting failures and pursued a root cause determination in a timely manner.
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3 OPERATIONAL SAFETY VERIFICATION (71707)
3.1 Control Room Observations
On a daily basis during regular onsite hours, and periodically during
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backshif t inspections, the inspectors observed control room operators and
shift turnover. The operators exhibited good communications with personnel
inside and outside the control room.
During this inspection period, a new
briefing was instituted where the shift supervisor or control room supervisor
provided a brief turnover to the entire crew, including the station operators.
This briefing was provided immediately following the shift turnover.
The
shift technical advisor was occasionally in attendance at this briefing. The
licensee has also had a fifth licensed operator on shift since November 3,
1993.
This additional licensed person on shift was on an interim basis
pending licensee evaluation to determine the usefulness of this position on a
permanent basis.
3.2 Plant Tours
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3.2.1
Reactor Water Cleanuo Valve Room
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On November 18, 1993, the inspectors toured the RWCU valve room to inspect the
condition of valves. The inspectors had previously noted that this. area
needed attention due to the large number of catch basins under the valves,
indicating leaking valves. During this inspection, no catch basins were
observed and the gene al housekeeping in the area was good.
3.2.2 Reactor Building Tour
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On November 18, 1993, the inspectors-conducted a general tour of all levels of
the reactor building.
Housekeeping throughout the reactor building was good
and improvement was evident. The inspectors observed ladders and carts -
securely chained and properly labeled. The inspectors also toured the
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alternate shutdown room and found it free of clutter.
The inspectors noted
-that' Emergency Light EE-LTG-R78 on the 935-foot elevation appeared to have an
electrolyte leak.
This issue was turned over to the shift supervisor and a
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maintenance work item was issued. During the tour, the inspectors noted
directional orientation of the emergency lights and the lights inspected
appeared to be properly oriented to perform their intended function.
The
inspectors observed the spent fuel pool and noted that it appeared free of
unnecessary items. The refueling floor was more than 60 percent
decontaminated and the general area was organized with equipment properly
stored.
3.3 Security Observations
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The inspectors observed various aspects of the licensee's implementation of
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security activities.
Personnel and packages entering the protected area were
observed to be properly searched. Vehicles were properly controlled or
escorted within the protected area.
During thi: inspection period, due to
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operability concerns with fire doors, security personnel were observed
performing fire watches. The inspectors found that the fire watches were
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knowledgeable of their responsibilities as fire watches and the actions they
would take in the event a fire occurred.
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3.4 Radiation Protection Activities
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The inspectors verified that selected radiological protection activities were
properly implemented and that radiation and contaminated areas were properly
posted and controlled. Health physics personnel were frequently observed
touring and monitoring the controlled areas. The inspectors noted that
accessibility and housekeeping of the areas under and on top of the. torus were
good.
On October 16, 1993, the licensee performed work to repair a leak on the main
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condenser. The inspectors noted a high level of awareness and attention given
to the preplanning of work to ensure radiation exposures were maintained at
levels as low as possible.
3.5 Conclusions
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The shift supervisor's crew briefings provided a summary of plant tatus for
the oncoming crew. This appeared to be helpful to the station operators.
The inspectors found that the licensee's efforts to improve general
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housekeeping in the plant had resulted in perceptible improvement. The RWCU
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valve room which had previously been identified as an area needing attention
was clean and valve leaks had been repaired.
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The inspectors found that fire watches posted as compensatory measures were
knowledgeable of their responsibilities as fire watches and the actions they
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would take in the event a fire occurred.
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4 MAINTENANCE OBSERVATIONS (62703)
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During this inspection period, the NRC conducted an Operational Safety Team
Inspection, which performed numerous maintenance observations. The results of
these observations will be documented in NRC Inspection Report 50-298/93-202,
5 SURVEILLANCE OBSERVATIONS (61726)
During this inspection period, the NRC conducted an Operational Safety Team
inspection, which performed numerous surveillance observations. The results
of these observations will be documented in NRC Inspection
Report 50-298/93-202.
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ATTACHMENT
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1 PERSONS CONTACTED
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1.1 Licensee Personnel
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L. E. Bray, Regulatory Compliance Specialist
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R. Brungardt, Operations Manager
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M. A. Dean, Nuclear Licensing and Safety Supervisor-
C. M. Estes, Corrective Action Program Overview Group
J. R. Flaherty, Corrective Action Program Overview Group
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R. L. Gardner, Plant Manager
M. D. Hamm, Security Supervisor
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G. R. Horn, Vice President, Nuclear
R. A. Jansky, Outage and Modifications Manager
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J. E. Lynch, Engineering Manager
J. M. Meacham, Site Manager
D. L. Reeves, Senior Staff Engineer
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J. V. Sayer, Radiological Manager
G. E. Smith, Quality Assurance Manager
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M. E. Unruh, Maintenance Manager
R. L. Wenzl, NED Site Engineering Manager
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V. L. Wolstenholm, Division Manager of Quality Assurance
1.2 NRC Personnel
J. E. Gagliardo, Chief, Project Section C (by telephone)
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The personnel listed above attended the exit meeting.
In addition to the
personnel listed above, the inspectors contacted other licensee personnel
during this inspection period.
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2 EXIT MEETING
An exit meeting was conducted on November 22, 1993.
During this meeting, the
inspectors reviewed the scope and findings of this report. The licensee
acknowledged the findings and did not identify as proprietary any information
provided to, or reviewed by, the inspectors.
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