ML20005D732
| ML20005D732 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 12/04/1989 |
| From: | Gagliardo J, Jaudon J, William Jones NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20005D731 | List: |
| References | |
| 50-458-89-41, NUDOCS 8912140371 | |
| Download: ML20005D732 (11) | |
See also: IR 05000458/1989041
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APPENDIX
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U.S. NUCLEAR REGULATORY COMMISSION
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RE,GION IV
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i NRC Inspection Report':" 50-458/89-41-
Operating License:
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Docket: 50-458
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Licensee: GulfStates'UtilitiesCompany--(GSU)
P.O.~ Box 220
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St. Francisv111e,- Louisiana 70775~
(Facility Name: River Bend Station (RBS)
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Inspection 4 At:" RBS. St. Francisville, Louisiana
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. Inspection Conducted: November 1-15, 1989'
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[ Inspectors:
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.E.CGgiardo, Chief,OperationalProgramsSection
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AI. B Jones, Resident Inspector
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agarr P. Jaudo ,=De
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11nspection Sumary
$ nspection Conducted November 1-15, 1989 (Report 50-458/89-41)
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Areas-Inspected: .Nonroutine, unannounced inspection of the reactor recirculation
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- flow control system malfunctions of January 17 and 18, 1989, and the management
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actions =related to the direction and oversight of these events...
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8912140371 891204
ADOCK 05000458
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Results: Within the area inspected, several potential violations were identified
involving failure to control troubleshooting and repair activities adequately.
- failure to perform post-maintenance testing, failure to take appropriate
corrective actions regarding the malfunctions, and failure to review and
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evaluate adeouately the malfunctions (Paragraph 2.).
Collectively, these
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potential violations raise serious concerns regarding'the effectiveness of
management's response to the malfunctioning flow control system, particularly
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since troubleshooting and repair activities resulted in inducing uncontrolled
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reactivity changes that resulted in several power and flow oscillations.
Further, management apparently failed to recognize the significance of the flow
control malfunctions and the resulting uncontrolled reactivity and flow oscilla-
tions. Consequently, corrective actions and actions to prevent recurrence did
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not provide adequate assurance that a similar event would be handled in a more
conservative manner.
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DETAILS
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Persons Contacted
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J. A. Bowlby, Shift Supervisor
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J. Boyle, Shift Supervisor
- G. A. Bysfield, Supervisor, Control Systems
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J. E Booker, Manager, Oversight
- J.,W. Cook, Lead Environmental Analyst, Nuclear Licensing
D. Dawson, Reactor Operator
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- T. C. Crouse, Manager, Ouality Assurance (0A)
J. C. Deddens Senior Vice President, River Bend Nuclear Group
- S. Finnegan~, Shift Supervisor
- L. A.' England. Director Nuclear Licensing
A.- 0. Fredieu, Supervisor, Operations
C. A. Fu, Field Engineer, G.
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K. J. Giadrosich, Supervisor, Cuality Engineering
P. D. Graham; Executive Assistant
D. Hicks, Field Engineering, G. E.
R. Jackson, Coordinator, Nuclear License Training
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M. Jones, Training Instructor
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- D. N. Lorfing, Supervisor, Nuclear Licensing
I. M. Malik Supervisor, Operations OA
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- W; H. Odell, Manager, Administration
- T. F. Plunkett, Plant Manager
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- M. F. Sankovich, Manager, Engineering
- J. P. Schippert Assistant Plant Manager, Operations and Radwaste
- R. G. West. Assistant Plant Manager, Technical Services
The inspectors also interviewed additional licensee personnel'during the
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inspection period.
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- Denotes those persons that attended the exit interview
conducted on November 15, 1989.
E. J. Ford, NRC Senior Resident also
attended the exit-interview,
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2.
' Reactor Recirculation Flow Control Valve Instability
This inspection was conducted to review a previous operational problem
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with the "B" reactor recirculation flow control valve-(FCV) that occurred
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on January 17-18, 1989. During the Maintenance Team Inspection (NRC
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Inspection Report 50-458/89-04) performed during the period of
September 18 through October 17, 1989, the inspector reviewed Condition
Reports 89-0042-and 89-0043, which documented operational instability of
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the "B" recirculation FCV. The inspector initiated an Unresolved Item
(458/8904-01) as a result of this review. The inspector's followup to
this Unresolved Item is discussed in the following paragraphs,
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-DETAILS-
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Persons Contacted
J. A. Bowlby, Shift Supervisor
J. Boyle, Shift Supervisor
- G. A.-Bysfield, Superviscr, Control Systems
~J. E. Booker, Manager.. Oversight
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- J. W. ' Cook, Lead Environmental Analyst, Nuclear Licensing
D. Dawson, Reactor Operator
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- T. C. Crouse, Manager, Ouality Assurance (OA)
J..C. Deddens Senior Vice President, River Bend Nuclear Group
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- S. Finnegan, Shift Supervisor
- L. A. England, Director, Nuclear Licensing
A. O. Fredieu, Supervisor, Operations
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C. A. Fu, Field Engineer, G. E.
K. J..Giadrosich,; Supervisor. Cuality Engineering
P. D.- Graham, Executive Assistant
D. Hicks, Field Engineering, G. E.
R. Jackson, Coordinator, Nuclear License Training
M. Jones. Training Instructor
- D.'N. Lorfing Supervisor, Nuclear Licensing
1. M. Malik, Supervisor, Operations OA
- W. H. Odell,' Manager, Administration
- T. F. Plunkett, Plant Manager
- M. F Sankovich, Manager, Engineering
, J. P. Schippert Assistant Plant Manager, Operations and Radwaste
'*R.-G. West, Assistant Plant Manager, Technical Services
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The inspectors also interviewed-additional licensee personnel during the
inspection period.
- Denotes those persons that attended the exit interview
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conducted on November 15, 1989.
E. J. Ford, HRC Senior Resident also
attended the exit interview.
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2.
Reactor Recirculation Flow Control Valve Instability
This inspection was conducted to review a previous operational problem
with the "B" reactor recirculation flow control valve (FCV) that occurred
on January 17-18, 1989. During the Maintenance Team Inspection' (NRC
Inspection Report 50-458/89-04) performed during the period of
September 18 through October 17, 1989, the inspector reviewed Condition
. Reports 89-0042 and 89-0043, which documented operational instability of
the "B" recirculation FCV. The inspector initiated an Unresolved Item
(458/8904-01) as a result of this review. The inspector's followup to
this Unresolved. Item is discussed in the following paragraphs,
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Background-
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On January 16, 1989, the licensee synchronized the main generator
onto the grid following replacement of a failed ground fault relay.-
Reactor power escalation continued through January 17,1989,' to
=approximately 8.4 percent. At 10:18'p.m., the "B" recirculation FCV
hydraulic power unit (HPU) tripped because of excessive servo error.
A control: room log entry made on January 17, 1989, at 10:18 p.m.,
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states that,
"HPU for 'B' flow control. valve tripped due to excessive servo
error. Valve position 76%.
Restored.HPU, zeroed servo error,
reset lockup.
Erratic cycling of servo error was observed with
valve motion attempting.to f ollow signal. HPU again tripped on
servo error (motion inhibit). Valve position 74%."
During the first event, the "B"
reactor recirculation loop flow
increased by approximately 2 million pounds mass per hour (mlbm/hr)
as indicated by the individual Recirculation Loop Flow Chart
Recorder B51-R614.- After restoring the "B" HPU and resetting the
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motion inhibit, the "B" recirculation loop flow decreased' by 1
mlbm/hr.
The "B" HPU remained shutdown with the "B" FCV in the " lockup"
condition. However, a slow hydraulic fluid leakage past the "B"
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actuator allowed the FCV to drift in the open direction. This
resulted in~ a slow reactivity addition to the reactor. During the
next 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, the reactor coolant flow through the "B" recirculation
loop , increased from approximately 29 mlbm/hr to 34 mlbm/hr. Because
of the increased feedwater demand resulting from the increased steam
production at the higher reactor thermal power (approximately
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92 percent), the reactor ^ operator at the controls (ATC) was required
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to place the startup feedwater regulating valvetinto service. At the
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time, the third _feedwater regulating valve had been tagged out-of .
service.and'was not available. Later, to maintain total reactor
coolant flow below the 100 percent core. flow limit of'84.5 mlbm/hr,
the ATC operator decreased the "A"
recirculation loop flow. -This
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placed the plant into a 2-hour Technical Specification Limiting
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Condition for Operation (Technical Specification 3.4.1.3) with thea
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recirculation loop flow mismatch greater than 5 percent with total
core flow greater than 70 percent. The* basis for the flow mismatch
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specification is to ensure compliance with the emergency core cooling
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system loss of coolant accident analysis design criteria for two
recirculation loop operation.
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On January 18, 1989, at 12:07 a.m., the licensee began inserting
control rods to reduce the control rod line to less than 80 percent.
This was. performed to ensure that if the recirculation pumps tripped,
the subsequent flow coast down would be below the area on the power-
to-flow map where thermal hydraulic instability had been experienced
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at other boiling water reactors.c (Referencellnformation4 Notice
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88-39: LaSalle Unit 2 loss of Recirculation, Pumps with_Powert
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Oscillation Event). This action was completed within'approximately'
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3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
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- ' At this time, the licensee initiated prompt Maintenance Work
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-Order (MWO) R56226 to troubleshoot the "B" FCV " lockup" and excessive'-
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positive and negative control demands. .The MWO authorized the
performance of. troubleshooting activities under the direction-of th5
system engineer. The system engineer subsequently directed the :
instrument and control (I&C) technicians to lift the'1eads from the
"B": FCV' linear variable differential transducer (LVDT), which provided
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feedback to the'"B" FCY controller on.FCV position.
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At approximately 1:40 a.m. on January 18, 1989, the ATC operator was
able to drive the?"B" FCV in the close direction. This was accomplished
by lifting the: leads from the "B"
FCV LVDT, which provided feedback
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to the "B"_FCV controller on FCV position. A negative servo error
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was then input on the "B" FCV by the ATC -operator. The "B" HPU then
started and the valve motion inhibit reset; When the valve reached-
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the desired position, the ATC operator tripped the HPU to stop the-
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. valve motion. The "B" FCV was again operated in the close direction
at approximately 4:00 a.m. on January 18, 1989, utilizing the method
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described above,
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At 6:00 a.m. on January 18. 1989, the oncoming operations crew
-relieved the operations crew that had originally experienced the
malfunction (RBS operations. crews work 12-hour shifts). -At approximately
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8:20 a.m., the ATC operator. attempted to close the "B" FCV by restarting
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the "B" HPU and resetting the motion inhibit. The operator input a
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. hen"the
small negative servo error as indicated by the controller.
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ATC operator reset the "B" FCV " lockup", the "B" FCV ramped open from
84 to 97 percent. Recirculation "B" loop flow changed between 30.5
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and 35.5 mlbm/hr. The ATC operator stopped the "B" FCV movement
by locking up the FCV. Total core flow increased to-104 percent ~and
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the recirculation loop 5 percent flow mismatch.. limit was exceeded.
Total core; flow remained above 104 percent for approximately 3.5
minutes before the ATC operator was able to close the "B" FCV to
match the "A" recirculation loop flow. Reactor thermal power increased
from approximately 74 to 77 percent as indicated by the average power
range monitor (APRM) strip chart.because of the above event. The
licensee has since postulated that the input servo error may have
actually been slightly positive, which ccused the "B" FCV to ramp
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open.
At approximately 11:50 a.m. on January 18, 1989, the ATC operator was-
able to operate the "B" FCV in the close direction to match the "A"
recirculation loop flow. This was necessary because of the "B"
drift that was experienced with the FCV in '? locked up."' In each of
the above cases, total core flow was allowed to drift to approximately
100 percent.
In each case, the licensee was relying on the malfunctioning
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control system to control reactivity and remain within the RBS
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Technical Specification limit for recirculation loop flow. The
"A" and "B" FCV were then operated in the close direction to reduce
total core l flow to approximately 85 percent.
As' a result of the-troubleshooting activities authorized by MWO RS6226..
the licensee concluded that a control card in'the "B" FCV control
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circuit had failed and that a solenoid valve in the "B" HPU was not-
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' operating properly. At approximately 2:30 p.m., the licensee reduced
total-core flow to 61 percent and reactor thermal power to 60 percent.
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This_ action was_taken by the reactor operators to place the "B"
recirculatior loop'into a condition where the "B"
FCV would not
drif t while the "B"' HPU was- out-of-service for the servo valve -
and control card replacement.- Another consideration regarding this
decision was the fact that a 10 percent recirculation loop flowa
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mismatch is, allowed with total core flow below 70' percent. The-
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control card replacement was authorized by MWO R56226 and the solenoid'
valve replacement was authorized by MWO R118514.p
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After completion of the above maintenance activities, at about.
4: 18 p.m., the "B" HPU was started. When the "B" FCV motion inhibit
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was reset, the "B" FCV immediately began following the oscillating
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servo error. .The amplitude of each FCV movement increased with each
cycle until the ATC operator shut down the "B" HPU af ter 5 seconds.
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The emergency response infomation system:(ERIS) data taken indicated'
neutron flux varied between 45 and 8B percent during th_e "B"
movement. Reactor thermal . power remained relatively steady. The
individual ' recirculation loop flow chart recorder indicated that the
"B" HPU was started and-the motion inhibit reset on at least three
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occasions following the above event. The individual recirculation
loop flow chart recorder indicated that similar "B"
FCV movements
occurred, but ERIS data was not archived fortthe subsequent "B"
' movements. The-licensee subsequently; determined that the linear
velocity transmitter had failed (as an open circuit) in the drywell,
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and-thus the "B" FCV control' circuity was not receiving a FCV velocity
feedback signal. During this period, the. licensee also determined
that the "B" FCV was moving in excess of the RBS Technical Specifica-
tion limit of 11 percent per second of valve stroke (Technical
-Specification 4.4.1.1.1).
The licensee subsequently declared the "B"
recirculation loop inoperable and entered single loop operation (SLO)
to correct the failed control circuitry.
Prior to the licensee implementing SLO on January 18, 1989, licensee
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engineering personnel discussed with the NRC resident inspector the
planned corrective maintenance actions for the "B" loop recirculation
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FCV. The inspector questioned the potential impact of the proposed
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technical solutions. Various applicable electrical drawings and
schematics were utilized during this process to verify that the
proposed actions would have conservative results.
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The licensee hali determined that a velocity transducer or its signal
wiring was open circuited for the "B" FCV,'thus causing it to be-
inoperable.. The licensee _prepered an unreviewed safety question
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determinationi(USOD) review for the proposed action which involved
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adjustments-to the FCV controller. The adjustments would have the
effect of changing the control of the FCV from a velocity and position
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controller.to a position controller only. Subsequent to these
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discussions,' the inspector discussed, with regional and NRR personnel,-
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the: details of the problems with the "B" FCV, the' licensee's planned
corrective actions, and their intent to go to single loop' operation.
In conjunction with entry into SLO, the inspector reviewed the-implemen-
tation of Procedure G0P-0004, " Single Loop Operation" and observed
Surveillance Test Procedure STP-050-3001, " Power Distribution- Limits
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Verification."
b.
Assessment'of the Malfunctioning Flow Control Valve System
This section of the report assesses the licensee's actions that
resulted in, or followed the events described in Section 2.a. above.-
It also identifies the potential violations that were identified by
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the inspectors.
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The licensee had experienced periodic problems with the recircu -
lation FCVs drifting during the 2 years prior to these events.
Corrective actions to stop the valves from drifting while
" locked up" were not effective until the FCV actuators were
rebuilt during the last refueling outage. Based on this past
experience, when the "B" HPU tripped to the maintenance mode on
January 17, 1989, because.of excessive FCV' servo error, the ATC
operator made several attempts to restart the "B" HPU. These
attempts resulted in the FCV moving with the oscillating servo
error, and ATC. operator intervention was required to " lockup"
the "B" FCV and terminate the "B" FCV movements.
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The MWO that authorized the-troubleshooting activities to be
perfomed at the. direction of the system: engineer did not provide
positive procedural controls. The engineer subsequently
directed the I&C technicians to lift the control leads from the
"B" LVDT. This resulted in the control system for the "B"
sensing the valve to.be at 50 percent open. With the leads
lifted, the ATC operator was able to establish a negative servo
error and drive the FCV in the close direction. The valve was
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then stopped by the ATC operator shutting down the HPU when the
valve reached the desired position. The licensee's failure to
provide positive procedural controls for the troubleshooting of
the flow control system (which involved lifting leads from the
control circuits) is a potential violation of Technical Specification 6.8.1.
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On January 18,'1989,'at approximately 8:20 a.m., the ATC operator.'
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apparently had not establish'a sufficient _ negative servo error
prior to restarting the "B"
HPU. When the FCV motion inhibit
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<was reset.ithe~"B" FCV ramped opened from 851t0 97 percent and
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~ he HPU shutdown. This caused the total-recirculation core flow)
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to exceed 10.4- percent for greater than '3 minutes until the "B"
FCV could be' driven,in the closed direction as described above.
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The licensee documented the above event in Condition
. Report 89-0042. This' is another example of insufficient proce-
dural guidelines / directions, which is'al potential violation
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o.f Technical' Specification 6.8.1 thatfled to an operational
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event.
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Replacement of the "B" FCV control circuit " Modicon" card and
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"B" HPU servo valve were authorized by MW0s R56226 and R118514 .
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respectively. Neither maintenance activity-had a specified
functional / operability test performed prior to placing the compo-
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nent back.in' service. -Gain ~ adjustments to both the position and
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velocity controllers appeared to have been made~on January 18,
1989, in accordance with field engineers direction, but the
unreviewed safety question determination was not performed 'ntil
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' January 21s 1989, when the nuclear steam supply systam vendor
recommended specific gain adjustments to make the controller
operate in the' proportional mode only( This is another example of
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activities, which were performed without specifically approved
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procedural. guidance / directions and constitutes a potential
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violation of Technical Specification 6.8.1.
The fact-that-th_e
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gain adjustment were made without a safety evaluation is also a
potential violation of the requirement of 10 CFR 50.59.
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Following replacement of the control card and solenoid valve,
the operator started the "B" HPU. When the FCV motion inhibit
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was reset, the FCV began tracking .the oscillating servo error
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signal. The FCV position modulated between 25 and 38 percent
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open. .The neutron flux subsequently varied between 45 and
88' percent as indicated on the APRMs. ~The neutron flux oscilla-
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tions were a direct result of the FCV movements. The. amplitude
of the valve swings, while tracking the servo error, increased-
with each cycle. The FCV cycled with a frequency of less than is
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Hz and the event was terminated by the ATC operator.after
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approximately 5 seconds. The "B" FCV was subsequently operated
an additional three times for troubleshooting activities as part
of MWO R56226.
In each case, the "B"
FCV attempted to respond
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to the oscillating servo error, and the flow charts indicated
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that flow oscillations similar to those in the initial event (at
8:20 a.m.) were experienced. The initial event was documented
by the licensee on Condition Report 89-0043. The licensee's
failure to have detailed post-maintenance test procedures-to
test the flow control system following the repairs and the fact
that the testing was performed on an operating loop led to
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the subsequent' power and flow oscillations ~ The licensee's
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Administrative Procedure - ADM-0028, " Maintenance Work Order,"
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Revision-10, paragraph 5.12.26 states, " Ensure post-maintenance
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- testing is performed and the required documentation-is-attached
to the MWO.
Appropriate post-maintenance testing shall be
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specified for all components that have been reworked, repaired,_
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Text / Operability Area of the MWO." "The licensee's failure to
replaced..or modified. . Record test results'in the Functional
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have documented post-maintenance testing of the required' flow-
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. control system with adjusted gain: controls, is a: potential
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violation of this procedure and Technical ^ Specification 6.8.1.
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On January 18. 1989, the licensee determined that the "B"
FCV:
movements documented in Condition Reports.89-0042 and 89-00431
exceeded the 11 percent per second Technical. Specification
limit for the. valve's movement in both open and close. directions.
- The licensee subsequently declared the "B" recirculation loop
inoperable and entered into single loop operation.- This-
determination was made after completion of the "B" FCV' trouble-
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shooting that led to the power and flow oscillation event described
in Condition Report 89-0043.
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Condition Report 89-0042 addresses the RBS Technical Specifica-
tion' requirement that the FCVs " lockup": on a loss of HPU pressure.
The operators' had observed a 13 percent per hour of full stroke
drift of the "B" FCV at the higher total core flow rates.- The
licensee cited the October 9, 1981, loss of coolant accident
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(LOCA) that analysis with recirculation FCV closure (LRG-II) in
determining'the FCV drift, with the valve " locked up," was
within the Technical Specification requirement. The LRG-II
analysis references the emergency core cooling system (ECCS)
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analysis presented in chapter 6.3 of the USAR which assumes the
FCVs undergo a " lockup" in their present position on high
drywell pressure following a LOCA. The analysis also assumes
' that one FCV fails to " lockup" and closes at'a rate of,11 percent
per second. The FCV closure results in an increased peak fuel
cladding temperature (PCT) of 450F. The increased PCT was
determined to remain within the limits of 10 CFR 50.46. Because
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the FCV drift problem had been in the conservate direction
(open) and the drif t rate magnitude was small, the licensee
concluded the "B" FCV was within the RBS Technical Specification
requirement for FCV " lockup". The inspectors did not concur
with this conclusion. The FCV had an uncontrolled drift of only
13 percent per hour, but this drift was observed in the " lockup"
mode when no valve movement was expected. The flow control
system was malfunctioning and the licensee did not take a
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conservative approach in their analysis.
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The licensee subsequently concluded that the 1,inear' velocity
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transducer had failed with an open circuit in the drywell. _ This
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resulted in the complete loss of the velocity feedback. signal to
the contro_1 system. During the second refueling outage, the
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licensee identified that fluid from the FCV actuator had leaked
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onto the linear.variab1e transducer (LVT) and caused the open
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circuit. A modification was made to'both FCVs to direct any
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' hydraulic fluid leaks away from1the:LVTs and the LYDTs.
The NRC staff is concerned;that in addition to the potential
violations,-the licensee's plant and engineering staff relied on
the malfunctioning "B" flow control system to maintain recircu-
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lation loop flows within the RBS Technical Specification mismatch
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limits. The' action resulted in uncontrolled reactivity' changes,
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c.
Management lnvolvement
Operations: management' up to the level of assiistant plant manager for.
operations;was aware of the flow control. problem at the time.of the
' event. ; Although the licensee did insert control rods and reduce the
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control rod line to less than 80 percent early in the sequence of-
events, it does not appear that stringent precautions or guidance was
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given to the. operators other than a' tacit approval to continue their
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troubleshooting activities.
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The inspectors interviewed the shift supervisors and other members of
the operating crews 'that were on shift during the course of these
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events. The operating log for the evening of January 17.--1989,
indicates that the operations supervisor was notified of the -problem
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- at about 10:30 P.M., which was s_hortly after the problem wi_th the FCV
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was'first observed. According to the shift supervisor that was on
watch at the time of the initial problem on January- 17, 1989, he was
notified by the operations supervisor to " restart the plant" Land
reset the " motion inhibit".for the FCV. The shift supervisor said
that every time they tried to reset the " motion inhibit" and tried to
close the' valve, it would begin to.open instead.
He said that the
engineer, who had been called in to troubleshoot the problem lifted
a lead in the circuit to restrict the motion of the-valve in the open
direction. An MWO (R56226)'had been issued to troubleshoot the flow
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control-circuit, but the inspectors found no definitive procedural
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controls cther than Procedure GMP-0042 (which is the procedure for
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controlling lifted leads) to cover these troubleshooting activities.
The inspectors asked the. operators if they were concerned about
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Two of the operators (one was a
shift supervisor)g with the plant.
what was happenin
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said that they were concerned about the uncontrolled
reactivity additions and had expressed their concerns to their management.
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The managers said that their' management was not happy with the
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situation, but they were satisfied with what was being done to
correct the problem.
None of those interviewed said that they had
recommended to their management that the plant be shutdown or that
the plant be placed into single loop operation until the problem was
resolved.
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After the problem had been. initially identified as being caused by a
defective: solenoid'and a defective control card, tie- solenoid and the
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control card were replaced. The licensee reduced tower and recircula-
tion flow to less than 60 percent;to make the repairs. Upon completing.
the repairs, the licensee perfonned what was termtd as' troubleshooting
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activities on the system. They did not term these activities as'
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post-maintenance testing, and no specific post-traintenance testing
was performed following the replacement of the card and solenoid.
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The " troubleshooting" activities that were performed following the
maintenance resulted in the; flow and power oscillations, which
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occurred on four separate occasions.
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d.
' Lessons Learned:and Corrective Actions
The inspection findings indicated that the licensee did not understand
the significance of the events of January 17 and 18, 1989. As a result,
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their corrective actions were not appropriate to the significance of
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-the events.
The. inspectors asked the individuals' interviewed to discuss the;
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lessons they learned from the events of January 17 and 18, 1989.
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Most of the individuals interviewed said that they could not think o.f
any lesson learned-from the events. A;few of the operators did note
that as a result of the events, they' had come to know. more'about <the
recirculation flow control system. Only one'of the individuals
interviewed expressed concern with what had happened;
He said that
he had mentioned' this concern to a manager. . His concern involved the-
fact' that specific procedural controls and technical" specifications
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are, prescribed for. reactivity additions because of control' rod
dri f ts. He said that the changes in recirculation flow,also induced
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reactivity changes -but.there werelno prescribed actions to be taken
forithis mode of reactivity addition. He said that he could not
understand why the recirculation flow changes were not covered by
similar Technical' Specification and procedural requirements;
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Several of the operators interviewed said that they had experienced
drifting with the FCV prior to the events of January '17 and 18,1989.
Apparently the. licensee's failure to recognize the significance of-
the earlier problem contributed to their failure to give more serious
attention to the events of January 1989.
The Independent Safety Engineering Group (ISEG) was tasked to analyze
the performance of the plant following the initial conduct of SLO.
Following the events of January 17-18, 1989, the plant entered into
SLO for the first time.
ISEG evaluated the SLO oprations and the
events leading to SLO. This evaluation was documented in Operating
Experience Report (0ER)89-004 that was issued on July 21, 1989. The
inspectors asked the individuals interviewed regarding their awareness
of the report, which analyzed-the events that led to the SLO and the
success of the SLO. Most of the individuals interviewed were unaware
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of the ISEG report, but said that'it may have been placed on their'
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required reading list and they.just did not_ recall it. The ISEG
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report addressed the flow oscillation problems and had a number of
good conclusions and recommendations that should have been the subject
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of critical evaluation by the plant staff. At the exit interview,
the inspectors were provided with a copy of the staff's response to
some of the~ recommendations of the report. The response, which was
dated November 7, 1989'(nearly four months after the report was
issued), did not address all of the report issues. The recommendations
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that were addressed (four of the six) were only marginally acceptable.
Recommendation 89-004-04, which urged the use of $1.0 to troubleshoot
flow control problems.and prevent the oscillations of January 1989 -
were not effectively addressed in the response. This does not reflect
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a strong safety concern on the part of plant management for a problem
s'that has such an effect on plant power levels.
The inspectors also asked the individuals interviewed to describe any
training-that-they had received-concerning the events of January
1989. The inspectors found that no training had been provided to the
operating crews regarding these events. The assistant plant manager
said that he believed:that the two condition reports, which described
the ev'ents, had been placed on the required reading lists for the
operators. The operators did not recall reading the condition
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reports, and the inspectors were not successful in locating a' copy of
the-required reading list that contained the subject condition-
reports. The training supervisor interviewed said that a training
subject, such as the condition reports, would normally not be placed
into the operator training schedule unless it was recommended by the
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operations staff. The licensee should consider the need for the
training staff to take a more pro-active approach to determining
lessons learned issues that need to be included in the training
programs for all plant disciplines.
The inspectors found that CA had performed a surveillance regarding
single loop operations, but they had not recognized the significance
of the events of January 1989 even though they had received the ISEG
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report and the two condition reports that addressed these events.
Cuality assurance:also needs to be more sensitive to these types of
events and take a pro-active approach to alerting management regarding
potential problems that have safety significance.
The inspectors found that the facility review committee (FRC) had
reviewed Condition Report 89-0042 for resolution of the FCV system
failures. However, the inspectors noted that the FRC did not consider
the fact that the operations staff was relying on the malfunctioning
FCV system to remain within the RBS Technical Specifications. This
condition was apparent in both Condition Reports 89-0042 and 89-0043.
The FRC, however, had not reviewed Condition Report 89-43, which
documented the flow and power oscillations. According to a licensee
representative they had not reviewed Condition Report 89-43 because the
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event reported in it did not involve a Technical' Specification limit
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being exceeded. The FRC's review responsibilities in Technical
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Specification 6.5.3 require that they review issues that present a
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potential hazard to nuclear safety. 'The events of. January 1989
certainly approach a reasonable threshold-for issues.that- should be
included in this' category.. This is a potential violation.of the ,
requirements of. Technical Specification 6.5.3.
The licensee needs to'
reevaluate the screening process employed to assure that this committee
is receiving the material (i.e. significant conditions reports)-
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necessary to carry out its intended mission.
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Conclusions
!:
The weaknesses identified in these sections indicate a number of
potential violations, wtiich individually may not constitute a signifi-
cant safety concern, but collectively raise serious questions regarding
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.the safety consciousness of the operations and engineering staffs and
'their managment. Further, the weaknesses. identified above regarding
the subsequent review and evaluation of this event raise concerns
about the effectiveness of management controls and oversight over the
RBS corrective action program. The apparent lack of responsiveness
of the operations staff to the ISEG report conclusions and.recommenda-
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tions'is of particular concern in this regard.
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3.
Exi t~- Interview
An exit' interview was conducted with licensee representatives! identified
in paragraph 1.on November 15, 1989. During this interview, the inspectors
reviewed.the scope and findings of the report. Other meetings between the
inspectors and licensee management were held periodically during the
inspection period to discuss identified concerns. The licensee-did not-
identify as proprietary any information;provided to, or reviewed by, the
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inspectors.
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