ML20034G900
| ML20034G900 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/03/1993 |
| From: | Gagliardo J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20034G898 | List: |
| References | |
| 50-298-92-26, NUDOCS 9303120070 | |
| Download: ML20034G900 (11) | |
See also: IR 05000298/1992026
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APPENDIX
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U.S. NUCLEAR REGULATORY COMMISSION
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REGION IV
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Inspection Report:
50-298/92-26
Operating License: DPR-46
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Licensee: Nebraska Public Power District
P.O. Box 499
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Columbus, Nebraska
68602-0499
Facility Name: Cooper Nuclear Station
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Inspection At:
Brownville, Nebraska
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Inspection Conducted: December 27, 1992, through February 6, 1993
Inspectors:
R. A. Kopriva, Senior Resident Inspector
W. C. Walker, Resident Inspector
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E. C. Collins, Project Engineer
Approved:
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J. E. Gagliardo, Chief,
oject Section C
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Inspection Summary
Areas Inspected:
Routine, announced inspection of onsite response to events,
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operational safety verification, maintenance and surveillance observations,
followup on corrective actions for violations, and open item followup.
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Results:
Design basis reconstitution process identified a safety concern
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pertaining to the emergency diesel generators and potential station
blackout condition.
Both onsite and offsite departments communicated
well to correct the deficiency. The licensee initiated and maintained
communications with the resident inspectors and the Regicn IV staff
throughout the event (Section 2).
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The inspectors found that control room operations during backshift hours
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were good (Section 3.1).
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The inspectors concluded that the licensee had provided good procedural
guidance to the operators to monitor and prevent reactor pressure vessel
stratification (Section 3.5).
The licensee performed an operability determination of the drywell--
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suppression chamber vacuum breakers.
NRC inspectors were informed
throughout the evaluation process, and good involvement was observed
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9303120070 930305
ADOCK 05000298
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between the licensee's operations and engineering departments-
(Section 5.1).
An emergency diesel generator surveillance and subsequent, repairs were
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performed well.
Good participation by operations, system engineering,
and maintenance organization was observed (Section 5.2).
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Quality oversight survey identified positive Quality Assurance
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involvement with respect to daily operational safety (Section 7.1).
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Summary of-Inspection Findings:
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Violation 298/9222-01 was closed (Section 6.1).
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Violation 298/9222-02 was closed (Section 6.2).
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Attachment:
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Persons Contacted and Exit Meeting
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DETAILS
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1 PLANT STATUS
At the beginning of this inspection period the plant had operated at or near
full power. On December 30, 1992, both diesel generators were declared
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inoperable due to seismic concerns with control circuits for associated
breaker lockout relays. A power reduction was initiated to comply with the
Technical Specification (TS) limiting condition for operation. As the reactor
approached 60 percent power, one of the diesel generators was declared
operable and the licensee terminated the power reduction. After completing a
modification to the breaker lockout relay control circuits, performing a
control rod adjustment, and control rod drive scram timing, the plant was
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returned to 100 percent power.
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From January 2 to 8,1993, the plant operated near full power.
From January 9
to 23, the plant was allowed to coast down in power prior to pulling the final
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control rods to an all-rods-out position. After achieving all-rods-out on
January 24, the plant returned to full power.
End-of-cycle power coastdown
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began on January 26 and continued through the end of the report period, at
which time the plant was at 93 percent of rated power.
2 ONSITE RESPONSE TO EVENT (93702)
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On December 30, 1992, both emergency diesel generators were declared
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inoperable. The licensee's design basis reconstitution review made a
determination that a loss of offsite power in conjunction with a seismic
event, tornado, or internal missile event could render both emergency diesel
generators (EDGs) inoperable. The licensee promptly declared an unusual event
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and commenced a power reduction after both EDGs were declared inoperable.
Based on the design basis reconstitution analysis, a portion of the breaker
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control wiring was determined to be located in nonseismic structures.
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control wiring were to be opened because of a seismic event, tornado, or
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internal missile event, the tie breakers would not trip open on an
undervoltage condition. The EDG Output Breakers EG1 and EG2 will not close if
the tie breakers are closed. As a result, the safety-related power source
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would be unavailable and the plant would be in a station blackout condition.
The unusual event was terminated after about 41/2 hours and the power
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reduction was stopped with the reactor at 65 percent power. The modification
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installed by the licensee to alleviate this possible design basis event
consisted of installing jumpers inside the essential switchgear breaker
cabinets to provide a parallel path for the trip circuit. This modification
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allowed for the opening of the circuit in the nonessential Class 1E switchgear
without disabling the essential Class IE portion of the circuit.
Had the Design Basis Event occurred, the control room would have had the
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following indications:
No AC power available
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EDGs running
EDG output breakers (EGI and EG2) not closed
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Based on the above indications and training received on similar scenarios, an
operator would be dispatched to the critical switchgear room to determine the
position of the tie breakers and manually trip them to the open position if
necessary. Once the tie breakers were tripped, the EDG output breakers would
automatically close and the EDGs would power the essential AC buses.
Once the potential concern had been identified by the licensee, communications
with the resident inspectors and the Region IV staff were established.
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resident inspectors monitored the licensee's actions pertaining to the reactor
power reduction and the installation of the modification to correct the
potential problem.
The inspectors reviewed with the licensee's procet'res and training related to
this type of situation.
Specifically, the station blackout procedure was
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reviewed and the inspectors found that it did require the operators to monitor
the appropriate instrumentation and to take the appropriate action to manually
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trip the circuit breakers.
It appears that the licensee would have likely
taken the appropriate actions had this event occurred.
3 OPERATIONAL SAFETY VERIFICATION (71707)
3.1 Control Room Observations
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The inspectors observed operational activities throughout this inspection
period to verify that proper control room staffing and control room
professionalism were maintained. Control room shif t supervisor log book, tag
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out log book, and control room balance-of-plant log book entries were reviewed
to verify that appropriate entries were made.
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During this inspection period the inspectors observed control room activities
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during numerous backshift and deep-backshift inspections.
No concerns were
identified or anomalies noted.
3.2 Plant Tours
The inspectors toured various areas of the plant to verify that proper
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housekeeping was being maintained.
Housekeeping was found to be adequate.
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The inspectors have noted that there had been an increase in work activity
throughout the plant due to the upcoming refueling / maintenance outage. The
licensee had expanded their efforts in controlling these activities.
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3.3 Radiological Protection Observations
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During the performance of plant tours and other inspection activities, the
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inspectors verified that selected activities of the licensee's radiological
protection program were properly implemented in conformance with facility
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policies, procedures, and regulatory requirements. Selected radiation and/or
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contaminated areas observed were properly posted and controlled. Health
physics personnel were observed to be touring work areas to ensure that proper
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radiological protection practices and radiological control requirements were
properly implemented. The inspectors independently monitored radiation levels
of selected areas of the reactor building, including the residual heat removal
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pump quadrants.
The inspectors verified that the measured radiation levels
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were consistent with the licensee's posted radiation levels.
3.4 Security Program Observations
Juring the performance of their plant tours the inspectors observed various
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aspects of the licensee's implementation of.their security program, such as
response to door alarms, access control at the primary access point, and
escort controls.
Discussions with security management confirmed their. review
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of security events that had taken place at other sites (i.e., Three Mile
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Island) and their review of the site security program pertaining to similar
events.
No concerns or anomalies were identified.
3.5 Reactor Vessel Stratification Prevention
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As a result of thermal stratification problems experienced at another boiling
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water reactor facility following a complex trip, the inspectors reviewed the
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licensee's procedures to monitor reactor vessel temperatures during heatup,
cooldown, and off-normal situations. The procedures included: Abnormal
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Procedure 2.4.2.2.4, " Reactor Vessel Cold Water Stratification," Revision 6;
General Operating Procedure 2.1.4, " Normal Shutdown From Power," Revision 37;
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and General Operating Procedure 2.1.1 "Startup Procedure," Revision 61.
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inspectors found detailed guidance in Abnormal Procedure 2.4.2.2.4 to monitor
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reactor vessel temperatures and to take steps to prevent reactor vessel
stratification.
In addition, the inspectors found that the general operating
procedures for heatup and cooldown required the monitoring of reactor vessel
temperatures during heatup and cooldown when the reactor was not vented.
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General Operating Procedures 2.1.1 and 2.1.4 contained updated TS figures
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delineating the reactor vessel pressure-temperature limitations.
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inspectors concluded that the licensee had provided good procedural guidance
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to the operators to monitor and prevent reactor pressure vessel
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stratification.
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Because of the occurrence of stratification at the other facility, the
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licensee had routed the information about the event to licensed operators.
The inspectors reviewed the routing sheet indicating that each licensed
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operator had reviewed the event.
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3.6 Conclusions
The inspectors found no distinguishable difference in control room operations
during backshift and deep back shift inspection as compared to day shift. The
control room operat.ons personnel performed their assignea tasks equally well
regardless of the differing shifts.
The inspectors noted during plant tours that the licensee had increased their
efforts in housekeeping in conjunction with the ongoing painting of the
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reactor building and with the upcoming refueling outage.
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The inspectors concluded that the licensee had provided good procedural
guidance and training to the operators to monitor and prevent reactor pressure
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vessel stratification.
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MAINTENANCE OBSERVATIONS (62703)
4.1 Diesel Fire Pump Preventative Maintenance
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On January 12, 1993, the inspectors obst/ved the replacement of fuel injection
lines for the diesel fire pump. The lines were replaced followi.19 an
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indication of fuel in the last oil sample analyzed. This repaii was in
addition to the yearly preventive maintenance activities (i.e., changing oil,
replacing oil and air filters, etc.,) conducted under Surveillr.ce
Procedure 6.4.5.9, " Diesel Fire Pump Inspection."
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The associated maintenance work order (92-3521) had been reviewed and approved
as noted by the cppropriate signatures, and the activity was found to be
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within the skills of the trade for the personnel involved.
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also noted that the system engineer responsible for diesels was present during
various stages of the maintenance activity and was involved in discussions
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pertaining to the condition of the diesel with the mechanics.
4.2 Conclusions
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The inspectors' observations and review of the diesel fire pump maintenance
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activity did not identify any concerns or anomalies. Maintenance personnel
were knowledgeable and familiar with the maintenance task.
The system
engineer's presence during the maintenance activity was noted as bene; cial to
both the system engineer and mechanics.
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SURVEILLANCE OBSERVATIONS (61726)
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5.1 Operability Evaluation of Drywell-Suppression Chamber Vacuum Breakers
en Otcember 22, 1992,- during routine surveillance testing of the drywell-
sq 9ression chamber vacuum breakers, the licensee discovered that the positive
disk position limit switch ' associated with Vacuum Breaker PC-A0V-NRV28 f ailed
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to provide a DISK NOT FULL CLOSED indication and annunciation ir, the control.
room. The vacuum breaker was declared inoperable and the limitit.g condition
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for operation entered. The inspectors reviewed the surveillance and the
licensee's actions for having declared the vacuum breaker inoperable.
On January 19, an additional drywell-suppression chamber vacuum
breaker (PC-A0V-NRV20) failed to provide a DISK NOT FULL CLOSED indication and
annunciation in the control room and was declared inoperable. The inspectors
again reviewed the licensee's actions and discussed the concerns associated
with the inoperable vacuum breabre..
During the initial licensing proceedings, the licensee committed to the
installation of a redundant " positive" valve disk indicating system in
response to the NRC concerns regarding the sensitivity of the existing
indicating system.
The NRC was concerned that the existing indication system,
which provides both open and closed indication, would not notify operators if
a vacuum breaker was partially open.
As a result, the licensee installed the
" closed" positive disk indicating system just prior to fuel loading.
Since the installation of these switches, occurrences have been identified
where these switches have failed to provide closed indication in the control
room.
In each instance, including the two present failures, differential
pressure testing of the torus-to-drywell vacuum breakers verified valve
closure and, in addition, control room indication provided by the redundant
cam-operated valve disk indicating system has provided additional confirmation
of valve closure.
The licensee had no history of any of the torus-to-drywell
vacuum breakers failing to open during the applicable surveillance tests, nor
had it been demonstrated through differential pressure testing that these
breakers had failed to close. The licensee planned to replace these switches
per Design Change 91-001 during the 1993 refueling outage with switches
specifically designed for this application.
The inspectors reviewed the licensee's evaluation of breaker position and
discussed the upcoming design change with the engineering department.
The licensee had prepared an eperability determination of the two inoperable
vacuum breakers based on the definition of operability as specified in their
TS and the consideration of both the cam-operated valve disk indicating system
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and differential pressure testing.
The licensee approved the operability
determination and during the next scheduled surveillance test verified
operability in the OPEN direction of all the vacuum breakers, including the
previously secured inoperable valves, and confirmed the operability in the
CLOSED direction through performance of the torus-to-drywell differential
pressure test.
The torus-to-drywell vacuum breakers were then declared
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operable, and the normal surveillance frequency of 30 days was resumed.
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The resident inspectors reviewed past records of inoperable vacuum breakers,
the surveillances in question, and the licensee's actions pertaining to the
operability determination. No concerns were identified.
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5.2 Diesel Generator Monthly Operability Test
on January 4, 1993, tne inspectors observed portions of diesel generator
Surveillance Procedure 6.3.12.1, " Diesel Generator Monthly Operability Test,"
Revision 34. The inspectors observed a reactor operator manipulate the
necessary switches to start Diesel Generator 1.
After starting the diesel, an
oil leak was observed by the system engineers.
The oil sensing line which
provides an indication of lube oil level for the diesel had a small leak which
was spurting lube oil. The reactor operator was also receiving a low lube oil
alarm in the control room. A decision was made to exit the surveillance and
declare the diesel inoperable.
The control room operator adhered to the
procedure and maintained good communication with the system engineer and
auxiliary operator throughout the surveillance. A maintenance work request
was issued and the diesel was repaired within several hours.
The surveillance
was completed satisfactorily with no further anomalies encountered.
5.3 Fire Pump Monthly Operability Test
On January 14, 1993, the inspectors observed Surveillance Procedure 6.4.5.3,
" Fire Pump Monthly Operability Test." This surveillance was run to verify
diesel fire pump operability following the preventive maintenance work. The
30-minute run was completed successfully and no discrepancies were noted. The
performance of this surveillance was acceptable.
5.4 Conclusions
The licensee actively pursued an operability determination of the drywell
vacuum breakers.
An appropriate level of management and engineering
involvement was acquired to adequately ascertain the operability of the vacuum
breakers. The inspectors 'cund the licensee's actions to be thorough.
The diesel generator surveillance was performed well. The personnel involved
were aware of the problems that were encountered and effectively pursued the
repair / replacement.
Repairs were expeditiously performed and the surveillance
was then completed satisfactorily.
6 CORRECTIVE ACTIONS FOR VIOLATIONS (92702)
6.1
(Closed) Violation 298/9222-01:
Failure to Control Flammable,
Combustible Material
from approximately April 11 through October 6, 1992, a helium compressed gas
cylinder on the refueling floor, an activity affecting quality, was not
secured to a fixed support and was not on a wheel-mounted cart of approved
design.
This was contrary to the licensee's approved procedures.
The helium compressed gas cylinder had been used to leak-test a reactor
pressure vessel surveillance specimen shipping cask.
The licensee's
corrective actions included promptly and properly securing and removing the
gas cylinder from the reactor building.
A walkdown of the safety sensitive
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areas of the plant was also conducted to determine whether any other similar
conditions existed and none were found.
The licensee has committed to revise their station procedure for proper
handling and securing of compressed gas cylinders, including a discussion of
the violation and clarification of the procedure at their general safety
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meeting.
6.2
(Closed) Violation 298/9222-02:
Failure to Use Proper Escort Procedures
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On Dctober 5, 1992, an individual with escort responsibilities did not
exercise and maintain control of a visitor
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Upon identification of the problem, the licensee escort promptly resumed
proper control of the visitor. Also, station security responded to ensure
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that the escorting responsibilities had been correctly executed. Additional'
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corrective steps taken included informing all station personnel of the
requirement and importance 9f line-of-sight control of visitors and including
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this event in initial and requalification training for escorts.
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OPEN ITEM FOLLOWUP (92701)
7.1 Quality Oversight Survey
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On January 5, 1993, the inspectors conducted an interview with the manager of
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Quality Assurance (QA) for Cooper Nuclear Station.
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around determining the extent to which onsite QA is involved in operational
safety at the site. The interview indicated that the QA organization was-
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active in the day-to-day operational safety of the facility. An exampie is
the required on-shift monitoring and documentation of operations personnel
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performance.
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The manager for QA also indicated that there was QA representation during Site
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Operations Review Committee meetings. This is the committee which has
oversight of operational safety determinations. The QA representative is a
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nonvoting member of the committee, but their involvement and concerns are
carefully reviewed by the committee.
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Based on the inspectors' interview, the licensee appears to have a QA program
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in place which is active in assuring operational safety at the facility.
7.2 Snubber Visual Inspection Intervals
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During the report period, the licensee raised a question pertaining to their
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TS Amendment 148, " Snubber Visual Inspection Intervals." The licensee
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questioned whether they could incorporate the 1991_ refueling outage data into
the amendment criteria, even though the snubber inspection had commenced prior
to the issuance of the amendment. 'The licensee initiated communications with
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the resident inspectors, Region IV staff members, and the Office of Reactor-
Regulations. The Commission reviewed the licensee's concern and concluded
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'that it was acceptable to include the 1991 snubber inspection results as part
of the TS amendment inspection interval criteria.
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7.3 Conclusions
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The licensee recognized a potential concern involving implementation of a TS
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amendment for snubber visual inspections. The licensee's licensing department
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initiated communications to clarify the issue. The results of the decision
were then used to incorporate the amendment inspection interval criteria into
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their upcoming 1993 refueling outage. Their actions should eliminate future
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confusion on this issue.
The inspectors reviewed the licensee's concerns and results and found that the ~
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licensing department had taken an active role in resolving potential questions
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on snubber visual inspection intervals prior to their occurrence.
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ATTACHMENT 1
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PERSONS CONTACTED
C. E. Bean, Construction Manager
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L. E. Bray, Regulatory Compliance Specialist
M. A. Dean, Nuclear Licensing and Safety Supervisor
J. R. Flaherty, Engineering Manager
S. S. Freborg, Plant Engineering Supervisor
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R. L. Gardner, Plant Manager
H. T. Hitch, Site Services Manager
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R. A. Jansky, Outage and Modifications Manager
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J. R. Myers, Senior Technical Staff Engineer
S. M. Peterson, Se., .r Manager. of Operations
J. V. Sayer, Radiological Manager
G. E. Smith, Quality Assurance Manager
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V. W. Stairs, Assistant Operations Manager
M. E. Unruh, Maintenance Manager
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The licensee personnel listed above attended the exit meeting held on
February 9, 1993.
In addition .o the personnel listed above., the inspectors
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contacted other personnel during this inspection period.
2 EXIT MEETING
An exit meeting was conducted on February 9, 1993.
During this meeting, the
inspectors reviewed the scope and findings of this report. The licensee did
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not identify as proprietary any information provided to, or reviewed by, the
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inspectors.
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