ML20217L721
| ML20217L721 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 04/28/1998 |
| From: | Leach M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20217L046 | List: |
| References | |
| 50-331-98-06, 50-331-98-6, NUDOCS 9805040285 | |
| Download: ML20217L721 (12) | |
See also: IR 05000331/1998006
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U. S. NUCLEAR REGULATORY COMMISSION
REGIONlli
Docket No:
50-331
License No:
Report No:
50-331/98003(DRS)
Licensee:
IES Utilities Inc.
200 First Street S.E.
P. O. Box 351
Cedar Rapids, IA 52406-0351
Facility:
Duane Arnold Energy Center
Location:
Palo, Iowa
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Dates:
March 18 - 20,1998
Inspectors:
M. Bielby, Reactor Engineer, Team Leader..
J. Larizza, Reactor Engineer
L. Collins, DAEC Senior Resident inspector (Acting)
M. Kurth, DAEC Resident inspector
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Approved by:
M. Leach, Chief, Operator Licensing Branch
Division of Reactor Safety
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9905040295 990428
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ADOCK 05000331
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EXECUTIVE SUMMARY
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Duane Amold Energy Center
NRC Inspection Report 50-331/98006
This special inspection reviewed operational and engineering aspects of the licensee's decision
to remove the manual rod control system from service and rely on the safety-related trip
function to insert control rods while the plant was operating at power. During this time, the
reactor was in a "coastdown" condition with all control rods fully withdrawn. Modifications were
performed on the reactor manual control system (RMCS) to remove spurious rod blocks and
nuisance alarms in the control room. The plant was about two weeks from a refuel outage and
plant management did not want these spurious rod blocks and alarms to interfere with an
orderly plant shutdown.
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Operations
The reduction of nuisance rod blocks and alarms to prevent unnecessary operator
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distractions showed good safety focus; however, the lack of Probablistic Risk
Assessment calculations for online RMCS maintenance led to a narrowly focused
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decision to perform the maintenance online. The Duane Arnold Energy Center technical
specifications do not address RMCS operability at power. (Section 01.2)
Operators were not timely in their recovery of normal manual rod control as indicated by
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the length of time the RMCS was allowed to remain out-of-service, and the time that
elapsed prior to conducting Post Modification Testing. (Section 01.3)
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The shift turnover sheets reflected the current status of the RMCS modifications.
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However, the Operating Log and Operations Shift Supervisor Log did not accurately
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document the status of reactivity control equipment and indicated a lack of attention to
detail. The six failures to make required log entries documenting the operational status
of the RMCS were considered a violation of 10 CFR 50, Appendix B, Criterion V.
(Section 01.4)
Engineering
The RMCS modifications appeared to correctly address the identified equipment
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problems. However, the post modification testing failed to verify the proper operation of
all components associated with the equipment modifications and was considered a
violation of Duane Arnold Energy CenterTechnical Specifications. (Section E1.2)
A 50.59 screening correctly identified that a safety evaluation for the RMCS
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modifications was not required. However, no 50.59 screening addressed removal of the
RMCS from service during plant power operation. The inspectors concluded that further
inspection was required to determine if a violation of 10 CFR requirements had
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occurred. This is considered an unresolved item. (Section E1.3)
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Report Details
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1. Operations
'01
Conduct of Operations
01.1 General Comments
During the month of ^v' arch 1998, the Duane Arnold Energy Center (DAEC) reactor was
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in a "coastdown" condition with all control rods fully withdrawn Spurious rod blocks and
nuisance alarms were being generated by the reactor manual control system (RMCS).
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Station management did not want these spurious rod blocks and alarms to interfere with
an orderly plant shutdown and directed technicians to install modifications in the RMCS
to repair the cause of the rod blocks and alarms. To successfully install the
modifications, the RMCS would have to be taken out-of-service. This special inspection
reviewed the licensee's decision to remove the RMCS from service while the plant was
operating at power and the decision to rely on the safety-related trip function to insert
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control rods during the RMCS outage.
01.2 Schedulina of RMCS Modifications
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a.
Insoection Scone (71707)
The inspectors conducted interviews and reviewed the licensee's preparations for the
RMCS modifications. The inspectors reviewed the following:
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Operations Instruction 856.1, " Reactor Manual Control System."
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Technical Specification 3.3.A.
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Technical Specification surveillance requirement 4.3.A.
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Corrective Maintenance Action Request A34101. " Install Surge Suppression To
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Prevent Rod Control Relays From Producing Period Alarms in SRMS (Source
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Range Monitors] Due to Electrical Spiking"
CMAR A39036," Remove 14 Rod Sequence Control System Relays No Longer
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Required For System Operation To Reduce Nuisance Control Rod Blocks"
CMAR A40308, " Change Two Resistors And Reinstall Two Varistors To Reduce
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Average Power Range Monitor Noise Interference From Reactor Manual Control
System Solid State Timer"
b.
Observations and Findinas
Three separate Corrective Maintenance Action Request (CMAR) work packages for the
RMCS modifications were generated by the licensee's engineering department and
submitted for implementation. The CMARs were approved and sent to scheduling. The
process for scheduling the CMARs included a review of the risks and benefits of
implementing the CMARs by a Scheduling Team. The scheduling team consisted of an
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operations shift supervisor (OSS), a scheduler, a work foreman, a system engineer
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. group leader, and a probabilistic risk assessment (PRA) representative.
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The scheduling team considered the following before scheduling the RMCS
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modifications during power operation:
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The plant was approximately two weeks from a scheduled refuel outage and
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plant management did not want spurious RMCS generated rod blocks and
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nuisance alarms to interfere with an orderly shutdown.
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There was no available PRA calculation for online maintenance on the RMCS.
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Online RMCS maintenance had not been factored into the licensee's
Probabilistic Safety Assessment mode!.
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Technical Specifications did not directly address removal of the RMCS from
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service with the plant at power.
Operations Instruction 856.1, Section 5.0, " Shutdown Of The RMCS," had a
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NOTE that stated, "The RMCS should be fully operational whenever the plant is
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operating or whenever control rod movement is desired. All or portions of the
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RMCS can be shutdown for repair or maintenance as necessary".
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The normal method of moving and positioning control rods during the RMCS
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outage would be unavailable; the safety-related trip function would be
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unaffected.
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Operating crews would be briefed to manually trip the reactor in response to any
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abnormal reactivity event.
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The reactor would be in "coastdown" with all control rods fully withdrawn and no
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requirement to move control rods for flux shaping.
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The RMCS had been previousty taken out-of-service while the plant was
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operating at power to complete RMCS repairs.
The licensee's team concluded the benefits involved in perforir.ing the RMCS
modifications during power operation and the contingency action developed for
addressing reactivity events made the risk acceptable.
Although the licensee observed that RMCS operability at power was not directly
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addressed in Technical Specifications, the inspectors noted that RMCS operability at
power was implied in the following Technical Specifications:
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Technical Specification 3.3.A.2.d which stated that the operators will have the
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ability to perform actions to recouple an uncoupled control rod, and to perform
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coupling checks on control rods when they reach the fully withdrawn position.
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Technical Specification surveillance requirement 4.3.A.2.f(l) stated a requirement
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to exercise each fully withdrawn control rod once per week.
c.
Conclusions
The reduction of nuisance rod blocks and alarms to prevent unnecessary operator
' distractions showed good safety focus; however, the lack of PRA calculations for online
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RMCS maintenance led to a narrowly focused decision to perform the maintenanco
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online.
01.3 Seauence of Events for Performance of RMCS Modifications
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a.
Insoection Scone (71707)
L The inspectors reviewed the sequence of events related to removing the RMCS from
service during power operation on two different occasions between March 13 and 17,
1998.' The inspedors reviewed the following documents:
Control Room shift tumover sheets and Operating and OSS logs for
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March 13-18,1998
Equipment Tagout Number 9802, " Reactor Manual Control System"
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.b.
Observations and Findings
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Friday, March 13,1998:
]
. The RMCS was disabled at 10:54 a.m. to begin modifications of 24 rod control relays
under CMAR A34101 (see section E1.2). The RMCS was not tagged out-of-service
because the affected relays could be removed, modified, tested, and reinstalled
individually. During each relay removal control room operators were unable to select
and move control rods using the RMCS. Performing the individual relay modifications _ in
this configuration minimized the time required to restore the system to operability. The
actual work took approMmately eight hours. The post modification test (PMT) of the
RMCS was completed at approximately 1:33 a.m. on March 14,1998.
Monday, March 16,1998:
The RMCS was tagged out-of-service at 9:42 a.m. by removing three power supply
fuses, and repositioning a rod movement control switch. Modifications were performed
on two relays under CMAR A40308. During this configuration, control room operators
were unable to select and move control rods using the RMCS. The licensee estimated
the time to restore RMCS operability would be 15-20 minutes. The restoration included
completion of immediate work, tag clearance, reinstallation of power supply fuses, and
repositioning of the rod movement control switch. The actual work duration was
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approximately three hours. No PMT was performed and the RMCS remained tagged
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out of service through the following day until the final modification was completed.
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Tuesday, March 17,1998:
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Modifications were performed to remove 14 rod sequence control system (RSCS) relays
and two associated annunciators under CMAR A39036. The work involved installation
of jumpers and retermination oileads. The licensee estimated it could restore the
RMCS to operability (clear tags, reinsiaii power supply fuses, and back out of the work
in progress)in approximately 15-20 minutes if it became necessary. However, it was
later determined that during one stage of the modification, the time to restore the RMCS
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to operability would be about three to five hours.
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The previously installed RMCS tagout was accepted at 3:41 a.m. and the actual work
duration was approximately eight hours. The tags were cleared at 1:20 p.m. Since the
RMCS was taken out-of-service at 9:42 a.m. on March 16, the RMCS had been
continuously out-of-service for over 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br />. The PMT was completed at 10:22 p.m.
During the time the RMCS was out-of-service the licensee was relying on the safety-
related reactor trip function to insert control rods for any reactivity event that may have
occurred.
c.
Conclusions
Operators were not timely in their recovery of the normal manual rod control as
indicated by the length of time the RMCS was allowed to remain out-of-service, and the
time that elapsed prior to conducting PMTs.
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01.4 Ooeratina and Ooerations Shift Suoervisor Loo Entries
a.
Insoection Scooe (717071
The inspectors reviewed the control room Operating Log, the Operations Shift
Supervisor (OSS) Log, and associated tumover sheets for the March 12 - 17,1998, time
period. The inspectors also reviewed the following procedures:
ACP 14.10.1, " Conduct of Operations" Revision 16
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ACP 1410.3, " Operating Logs," Revision 3
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b.
Observations and Findings
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The inspectors noted that ACP 1410.3, Section 3.2, required entries in the Operating
Log each shift for equipment removed and returned to service. The inspectors also
noted that ACP 1410.3, Section 3.3, required entries in the OSS Log each shift for
maintenance on major equipment.
On March 13,1998, both control room logs identified the start of RMCS modification
CMAR A34101. The individual turnover sheets for the Shift Manager, Nuclear Shift
Operations Engineer, and OSS appropriately identified the status of the RMCS
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modifications throughout the various shift reliefs. Both control room logs identified the
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start and completion of the PMT for the RMCS. However, neither the Operating Log nor
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the OSS Log identified completion of CMAR A34101, nor the RMCS return to service.
The two failures to make required log entries documenting the operational status and
authorized work of the RMCS were considered violations of 10 CFR 50, Appendix B,
Criterion V. (VIO 50-331/98006-1a and -1b(DRS))
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On March 16,1998, the individual tumover sheets for the Shift Manager, Nuclear Shift
Operations Engineer and OSS appropriately identified the status of the RMCS
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throughout the CMAR A40308 modifications. However, the Operating Log did not
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contain an entry for removal of the RMCS from service, and the OSS Log did not identify
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a start or completion time for CMAR A40308. The two failures to make required log
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sntries documenting the operational status and authorized work of the RMCS were
considered violations of 10 CFR 50, Appendix B, Criterion V. (VIO 50-331/98006-1c
and -1d(DRS))
On March 17,1998, the individual tumover sheets for the Shift Manager, Nuclear Shift
Operations Engineer and OSS appropriately identified the status of the RMCS
throughout the CMAR A40308 modifications. Both control room logs identified the start
and completion of the PMT for the RMCS. However, the Operating Log did not contain
an entry for restoration of the RMCS to service, and the OSS Log did not identify a start
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or completion time for CMAR A39306. The two failures to make required log entries
documenting the operational status and authorized work of the RMCS were considered
violations of 10 CFR 50, Appendix B, Criterion V. (VIO 50-331/98006-1e and -1f(DRS))
c.
Conclusions
The shift turnover sheets reflected the current status of the RMCS modifications. The
Operating Log and OSS Log did not accurately document the status of reactivity control
equipment and indicated a lack of attention to detail. The six failures to make required
log entries documenting the operational status of the RMCS were considered a violation
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of NRC requirements.
Ill. Enaineerina
E1
Conduct of Engineering
E1.1
General Comments
The inspectors reviewed the engineering department's involvement in evaluation and
modification testing of the reactor manual control system while the plant was operating
at power. The inspectors conducted personnel interviews and reviewed selected
portions of certain procedures and representative records.
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E1.2 Review of RMCS Corrective Maintenance Action Reauests
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a.
Insoection Scoce
The inspectors assessed the work packages for performing RMCS modifications, and
reviewed the PMT in detail with the system engineer. The following were also reviewed
by the inspectors:
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Maintenance Directive MD-024, " Post Maintenance Testing Program,"
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Revision 12
b.
Observations and Findings
The licensee prepared three CMARs to address nuisance rod blocks and annunciators
associated with operation of the RMCS. The work was considered an Engineered
Maintenance Action, and the PMT was required by MD-024. The inspectors noted that
Technical Specification 6.8.1 required that procedures addressing testing requirements
for equipment that could have an impact on the nuclear safety of the facility shall be
implemented. MD-024 required that post maintenance testing be performed, if
appropriate, following corrective maintenance on components regardless of Quality
Level to verify: the ability of the system or component to perform its intended function,
the original deficiency was corrected, and no new problems were created.
CMAR A34101 was initiated September 12,1996, to eliminate circuit noise from 12 rod
control relays that produced " spiking" of source range monitor indications. The identified
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solution was to install surge suppression resistor-capacitor (RC) filters across the coil of
each rod control relay. The PMT was identified as STP 3.1.3-01. The inspector
requested a detailed review of STP 3.1.3-01. During the review, the system engineer
acknowledged that the PMT did not test the " Continuous insert" relay (C11-K018)
subsequent to completion of the modification. This was considered a violation of DAEC
Technical Specifications. (VIO 50-331/98006-02a(DRS)).
CMAR A39036 was initiateo October 15,1997, to eliminate nuisance rod blocks from 14
RSCS relays that were no longer required to be functional by Technical Specifications.
Additionally, the two associated annunciators were not required to be operable. The
identified work was to install jumpers, reterminate leads, and subsequently remove the
relays and annunciators. The PMT was identified as performance of" Rod Adjustment
Sheets, Version 98-005, A2 Sequence."
CMAR A40308 was initiated December 8,1997, to eliminate electronic noise
interference with te average power range monitors (APRMs) during rod movements at
reactor power levels less than approximately 12%. The interference caused nuisance
APRM downscale annunciators. The identified resolution was to install smaller resistors
in the RC filter for each of two relays, and reinstall a previously removed (CMAR
A36763) metal oxide varistor across each coil of the same two relays. The two relays
were part of the RMCS solid state timer that provided timing sequences to operate the
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control valves on the hydraulic control units for control rod movement. The PMT was
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identified as performance of" Rod Adjustment Sheets, Version 98-005, A2 Sequence."
The inspector requested a detailed review of the PMT. During the review, the system
engineer acknowledged the PMT did not test the " solid state timer malfunction"
computer points subsequent to completion of the modification. This was a second
example of a violation of DAEC Technical Specifications. (VIO)(50-331/98006-
02b(DRS)).
c.
Conclusions
1
The RMCS modifications appeared to correctly address the identified equipment
problems. However, the post modification testing failed to verify the proper operation of
all components associated with the equipment modifications and was considered a
violation of DAEC Technical Specifications.
E1.3 Taking RMCS Out-Of-Service During Power Ooeration
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a.
Insoection Scooe
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The inspectors reviewed the details of removing the reactor manual control system from
service for an extended period of time with the plant operating at full power.
b.
Observations and Findings
The licensee performed a 10 CFR 50.59 review of the three CMARs which determined
that a safety evaluation for the RMCS modification was not required. However, the
screening did not reference the removal of the RMCS from service during normal power
operation.
The licensee's Technical Specifications did not address the rod control system
operability directly. Technical Specification 3.3.A.2.d implied that an operator will have
the ability to perform actions to recouple an uncoupled control rod and to perform
coupling checks on control rods when they reach the fully withdrawn position.
Technical Specification surveillance requirement 4.3.A.2.f(l) implied that the rod control
system will be operable since it contains a requirement to exercise each fully withdrawn
control rod once per week.
The licensee's Updated Final Safety Analysis Report (UFSAR) Chapter 7.7.3.1, " Power
Generation Objective," stated "The objective of the reactor manual control system is to
provide the operator with the means to make changes in nuclear reactivity so that
reactor power level and power distribution can be controlled." Furthermore, UFSAR
Chapter 15.1.2, " Loss of a Feedwater Heater," stated "If power exceeded the normal
full-power flow control line, the operator would be expected to insert control rods to
return the power and flory to their normal range. If this was not done, the neatron flux
could exceed the scram setpoint causing a scram."
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On March 13,16 - 17,1998, the licensee operated the RMCS in a manner not described
in UFSAR Sections 7.7.3.1 and 15.1.2. A written safety evaluation had not been
performed to determine whether or not the change to the system configuration specified
in the UFSAR involved an unreviewed safety question. Specifically, no safety screening
evaluation was performed for the removal of the RMCS from service with the reactor at
power.
c.
Conclusions
A 50.59 screening correctly identified that a safety evaluation for the RMCS
modifications was not required. However, no 50.59 screening addressed removal of the
. RMCS from service during plant power operation. The inspectors concluded that further
inspection was required to determine if a violation of 10 CFR requirements had
occurred. This is an unresolved item. (URI 50-331/98006-03(DRS)).
V. Management Meetings
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Exit Meeting Summary
The inspectors presented the inspection results to members of licensee management at the
conclusion of the inspLtion on March 20,1998. On April 8,1998, a telephone exit was
conducted to inform the licensee that a potential violation item discussed during the exit on
March 20,1998, would become an unresolved item. The licensee acknowledged the findings
presented.
The inspectors asked the licensee whether any materials examined during the inspection
should be considered proprietary. No proprietary information was identified.
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PARTIAL LIST OF PERSONS CONTACTED
Licensee Exit. March 20.1998
J. Bjorseth, Maintenance Manager
D. Curtland, Operations Manager
J. Easton, Procedures Supervisor
J. Franz, Senior Vice President Nuclear Generation
B. Hopkins, PSA Engineer
K. Huber, Systems Engineering Supervisor
M. Huting, Program Engineer Supervisor
K. Kleinheinz, Scheduling
D. May, Maintenance Process Support Sup.
M. McDermot, Engineering Manager
D. Mienke, Nuclear Design
K. Morgan, Quality Assurance
R. Murrell, Licensing
K. Peveler, Regulatory Performance Manager
J. Probst, Engineering Maintenance Rule Coordinator
J. Quimby, l&C Project Engineering
C. Sullivan, Systems Engineering
G. Van Middlesworth, Plant Manager
Telechone Exit. Acril 8.1998
M. Davis, Assistant Operations Supervisor
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R. Murrell, Licensing
K. Peveler, Regulatory Performance Manager
G. Van Middiesworth, Plant Manager
D. Wilson, Assistant Vice President Nuclear Generation
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M. Bielby, Reactor Engineer
L. Collins, DAEC Senior Resident inspector (Acting)
M. Kurth, DAEC Resident inspector
J. Larizza, Reactor Engineer
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INSPECTION PROCEDURE USED
Conduct of Operations
ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
50-331/98006-01
Inadequate operating ';g entries for work on RMCS
50-331/98006-02
Inadequate post modi cation testing on RMCS
a
50-331/98006-03
Inadequate 50.59 serr sning for taking RMCS out-of-service
during power operation
Closed
None
Discussed
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None
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