ML20126B499
| ML20126B499 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 12/09/1992 |
| From: | Hague R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20126B480 | List: |
| References | |
| 50-461-92-20, NUDOCS 9212220112 | |
| Download: ML20126B499 (12) | |
See also: IR 05000461/1992020
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U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Report No.
50-461/92020(DRP)
Docket No.
50-461
License No. NPF-62
Licensee:
Illinois Power Company
500 South 27th Street
Decatur, IL 62525
facility Name:
Clinton Power Station
Inspection At:
Clinton Site, Clinton, Illinois
Inspection Conducted:
October 27 - December 7, 1992
Inspectors:
P. G. Brochman
F. L. Brush
M. J. Miller
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Approved By: /
/>/'//9v
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lague/ Chief
Date
M ichard L./jects Section IC
Reactor Prb
Inspection Summary
Inspection from October 27 through December 7.1992. (Recort No.
50-461192020(DRP))
Areas Inspected:
Routine, unannounced safety inspection by the resident and
region based inspectors of licensee actions on previous inspection findings,
plant operations, radiological controls, maintenance and surveillance,
security, engineering and technical support, safety assessment and quality
verification, and management meetings.
Results:
Of the seven areas inspected, no violations or deviations were
identified-in six areas: one violation was identified in the remaining area:
(entry into an operational condition with required equipment _ inoperable -
paragraph 3.c).
One unresolved item was identified concerning the analysis of
potential fires in the offgas charcoal absorber beds (paragraph 2.b).
The following is a summary of the licensee's performance during this
inspection period:
Plant Operations
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The ' reactor operators response on entry into the power-to-flow
instability region was excellent.
A manual scram was promptly made and
no' power oscillations were observed.
9212220112 921211
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The plant entered Operational' Condition 2 with the drywell and
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containment H,/0, analyzer inoperable.
Maintenance and Surveillance-
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Additional failures of the reactor feedwater pump throttle linkages
occurred. The licensee replaced the bronze bushings with tapered roller
bearings.
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An excellent effort by the maintenance and engineering personnel
identified a manufacturing defect in the number one service air
compressor's fourth stage seal air hole. This problem had caused
excessive oil leakage, vibration, and also affected motor bearings.
analyzer was a
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Contributing to the operations problem with the H,/0,izing that
failure to utilize written procedures and not recogn
reprogramming a microprocessor was performing maintenance.
Security
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A review of the fitness for duty program did not identify any
deficiencies.
Enaineerina and Technical Suonort
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An excellent analysis was performed by the engineering staff of
overheating of electrical relays utilizing a ganged configuration.
The
scope of the analysis was expanded beyond the specific concern
identified in an NRC-information notice and was very thorough.
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A review of the accident analysis section of the Clinton Updated Safety
Analysis Report (USAR) indicated that an offgas charcoal adsorber fire-
had not been adequately analyzed for the potential release of fission
products to the environment; and that non-conservative assumptions
appeared to have been utilized.
Safety Assessment and Quality Verification
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The quality of a third-party audit of the quality assurance (QA)
organization was excellent.
Several improvement items and one weakness 1
were identified,
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DETAILS
1. Persons CEDIACitd
Illinois Power Company (IP)
- J. Perry, Senior Vice President
- J. Cook, Vice President and Manager of Clinton Power Station (CPS)
- J. Miller, Manager - Nuclear Station Engineering Department (NSED)
- R. Wyatt, Manager - Quality Assurance
F. Spangenberg, III, Manager - Licensing and Safety
- R. Morgenstern, Manager - Training
- J. Palchak, Manager - Nuclear Planning and Support .
- L. Everman, Director - Radiation Protection
P. Yocum, Director - Plant Operations
W. Clark, Director - Plant Maintenance
- R. Phares, Director - Licensing
- K. Moore, Director - Plant Technical
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W. Bousquet, Director - Plant Support Services
C. Elsasser, Director - Planning & Scheduling
S. Hall, Director - Nuclear Program Assessment
J. Sipek, Supervisor - Regulatory Interface
- D. Korneman, Director - Systems and Reliability, NSED
- R. Kerestes, Director - Nuclear Safety and Analysis
- J. Langley, Director - Design and Analysis, NSED
The inspectors also contacted and interviewed other licensee and
contractor personnel during the course of this inspection.
Denotes those present during the. exit interview on December 7, 1992.
2.
Action on Previous Inspection Findinos (92702)
a.
(Closed) Unresolved Item (461/91018-01(DRP)):
Blown fuse in
standby gas treatment system (SBGT) affects other' components. On
August 28, 1992, a fuse failed in a load-driver for the SBGT
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relays. This condition was alarmed and the-licensee replaced the
blown fuse within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. A subsequent evaluation indicated that
multiple components in Division I would have failed to actuate on
valid high radiation or loss of coolant accident signals.
The
inspectors had requested the licensee evaluate the reportability-
of this event, the system's conformance.to General Design
Criterion (GDC)~23, and the information contained in the
annunciator response procedures.
The licensee's analysis concluded that this event was not
reportable since no technical specification action statements were
exceeded, redundant isolation valves existed, or. equipment
received start signals from other process parameters.
The
licensee concluded that while selected valves would not fail to
their safety position, on a loss of power,- that the safety
function was designed against a single failure. Therefore, the
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failure of one division would not prevent the operation of the
other and the plant's design was in conformance with GDC 23.
The licensee did revise its annunciator response procedures and
operator training to recognize that the failure of this fuse would
affect more components than the SBGT system.
Based on the
licensee's corrective actions and evaluations, the inspectors have
no further concerns. This item is considered closed,
b.
(Closed) Open Item (461/92010-03(DRP)):
Questions on the design
of the offgas charcoal adsorber system.. The inspectors had asked
three questions on design information for the offgas system, which
was contained in the'Clinton Updated Safety Analysis Report
(USAR). The licensee had responded to the first question and was
still evaluating questions two and three. Question one related to
the fact that USAR Table 11.3-5 did not consider the possibility
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of a charcoal fire in the " equipment malfunction analysis".
The licensee stated that a charcoal adsorber fire was an event
rather than an equipment malfunction. And that this ev'at was
analyzed in USAR Chapter 15. The inspector reviewed the analysis
in Section 15.7.1.1 and identified that the assumptions used
appeared to be non-conservative and did not reflect the .
possibility that a high temperature charcoal fire might result in
the release of fission products to the environment.
In USAR Section 15.7.1.1.5.2, " Design Basis Analysis," a seismic
event was considered as the only conceivable event which would
cause significant system damage; and therefore release of
radioactive material to the environment. A fire was not
considered a reasonable possibility. However,-a high temperature
fire had already occurred at Clinton and the inspector considered
the question moot as to whether a fire was possible.
Given that a charcoal fire is a credible event, the following
assumptions necd-to.be considered. .First, any radioactivity which
had been adsorbed by the charcoal would be released as the carbon
matrix was consumed; rather than being retained, as the USAR
assumptions stated.
Second, the source term used for the analysis
might not include the proper quantity of long term fission
products retained by the charcoal at the end of plant life.
Third, and more importantly, to extinguish _ the fire, nitrogen gas
(N,) would be used to purge the charcoal . beds.
However, to purge
the N, into the beds an outlet path must be _available.
Consequently, any radioactivity which was released would have an
exhaust path to the environment.
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The inspector qu'estioned if-the USAR analysis accurately addressed
this accident and whether releasing the maximum possible, end of
life, quantity of fission products stored in the charcoal adsorber
beds-would result in offsite doses outside of the-limits of 10 CFR Part 100, " Reactor Site Criteria." This issue will be followed as
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Unresolved Item (461/92020-01(DRP)).
The issues raised-by the
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open item all remain open; however, they will be tracked under
this unresolved item; consequently, this open item is considered
closed.
No violations or deviations were identified.
3.
Plant Qnerations
The unit operated at power until 3:12 a.m. on November 22, 1992, when
the unit was manually tripped due to entry into the power-to-flow
instability region. The reactor was taken critical on November 24.
The reactor operated at power for the remainder of the report period,
a.
Onsite Event Follow-uo (93702)
The inspectors performed onsite follow-up activities for an event
which occurred during November 1992. Details of the event and the
licensee's corrective actions developed through the inspectors
follow-up are provided below:
Manual Reactor Trio yoon Entry Into the Power-to-Flow Instability
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Region
At 3:12 a.m. on November 22, 1992, with reactor power at 75
percent, the "B" reactor feed pump (RFP) minimum flow valve failed
open, diverting feedwater flow from the reactar.
The "A" RFP was
out of service to inspect its throttle linkage bearings. The
diverted feedwater caused reactor level to drop from the normal
level of 36 inches [91.4 cm] to approximately 28 inches [71.1 cm].
The reactor recirculation flow control valves (FCV) then ran back
to their minimum position when reactor water level reached the
Level 4 setpoint - 30.8 inches [78.2 cm] - coincident with one RFP
in operation. The FCV runback decreased reactor power into the
power-to-flow instability region. The reactor operator
immediately tripped th_ reactor per procedure.
No power
oscillations were observed.
All systems- responded as designed and
the unit was stabilized in hot standby.
The minimum flow valve failed open due to a loss' of instrument air
(IA). The copper IA supply line failed immediately upstream of
the fitting connecting it to the valve's operator. The licensee
believed this was due to vibration induced stress hardening.- The
IA lines to both the "A" and "B"'RFP minimum flow valves were
replaced using stainless steel flexible hoses.
The licensee had
developed a generic modification, FECN 24523 - in 1989 - to
replace copper IA lines after they' fail.
The licensee intends to
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inspect other copper IA lines before the end of the next refueling
outage and replace susceptible IA lines before a failure occurs.
The licensee was also evaluating the operation of the flow control
runback to determine if it could be set to a higher value or if it--
could be disabled if the plant is already operating on one RFP.
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The response of the reactor operators was excellent in assessing
the situation and promptly scramming the unit before any
oscillations began. Operations personnel had recommended before
the downpower that control rods be inserted below the 80% rod line
on the power-to-flow map; however, management had chosen not to do
this.
If this had been done the reactor would not have entered
the power-to-flow instability region when the FCV ran back;
removing the need for the scram.
During the subsequent repairs to
the B RFP, control rods were left inserted below the 80% rod line.
The inspectors will perform further reviews of this event after
the LER is issued.
b.
Operational Safety (71707)
The inspectors observed control room operation, reviewed
applicable logs, and conducted discussions with control room
operators. During these discussions and observations, the
operators were alert, cognizant of plant conditions, attentive to
changes in those conditions, and took prompt action when
appropriate. The inspectors verified the operability of selected
emergency systems, reviewed tagout records, and verified the
proper return to service of affected components.
Tours of the circulating water screen house and auxiliary,
containment, control, diesel, fuel handling, rad-waste, and
turbine buildings were conducted to observe plant equipment
conditions, including potential fire hazards, fluid leaks,
excessive vibrations, and to verify that maintenance requests had
been initiated for equipment in need of maintenance.
The inspectors observed plant housekeeping and cleanliness
conditions and verified implementation of radiation protection
controls and physical security plan.
c.
Ooerational Condition Chance With a Hydrocen/0xvaen Analyzer
Inocerable
At 8:56 p.m. on November 23, 1992, the reactor entered Operational
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Condition (OC) 2, "Startup". At 9:20 a.m. on November 24, 1992,
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operations personnel discovered that the Division II drywell and
containment H,/0, analyzer was inoperable. On November 22, 1992,
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operations personnel had requested that maintenance personnel run
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the Division II H /0, analyzer through its calibration cycle to
verifyitwasworkingproperly.
To accomplish this task,
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maintenance personnel had to reprogram the microprocessor - which
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controlled the analyzer - to execute a calibration cycle at that
time, rather than the usual time of 8:10 a.m. each day. This task
was successfully completed and at 10:30 a.m. maintenance personnel
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then reentered the commands to return the monitor to its normal
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routine. However, the maintenance technician who performed this
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task made a personal error and transposed two numbers in the
commands he entered. This rendered the analyzer inoperable. This
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condition was not recognized until November 24, 1992, after the
unit was started up.
There were several causes to this event:
1.
The controller for the H,/0, analyzer was not designed
to support the performance of a calibration check on
demand, but required that the controller's software be
reprogrammed.
2.
Neither operations nor maintenance personnel
recognized that reprogramming the controller was
performing mair' aance on the analyzer. Consequently,
administrative ,,rocedures, which would require that
the monitor be declared inoperable and
post-maintenance testing be performed, were not
implemented.
3.
The maintenance personnel performing this task did not
utilize any written instructions or procedures.
4.
There was no independent verification to assure the
quality of the sof tware commands was maintained.
5.
Operations personnel did not observe the printout on
November 23, 1992, which would have indicated that the
monitor was inoperable. Technical specifications did
not require that a channel check be performed daily,
but only monthly on the H,/0, analyzers.
Technical specification (TS) 3.0.4 required that entry into an
operational condition shall not be made unless the condition for
the limiting condition for operations are met.
Technical specifications 3.3.7.5, Table 3.3.7.5-1, Instrument 7, required
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that both the Division I and II containment and drywell H /0,
analyzers be operable in OC 1, 2, and 3.
Thefailuretobaveboth
H,/0, analyzers operable during entry it,to DC 2 was a violation of
technical specification 3.0.4 (416/92020-02(ORP)).
From a listing of the causes of this event it was apparent that
the licensee's " software QA" program had failed to prevent this
problem. The licensee had recently revised its software QA
program and had just issued it before this event occurred;
however, the new program had not been implemented.
In its
response to the violation, the NRC requested the licensee address
whether its newly issued software QA program adequately controls
activities on this type of safety-related computer.
As corrective action the licensee has developed procedures to
change the programming on the controller and briefed maintenance
and operations personnel on this event. The inspectors will
review this event further after the LER is issued.
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No deviations were identified. One violation was identified.
4.
Radiolooical Controls (71707)
External Surveys
As part of routine monitoring, the inspectors performed a radiological
survey to verify accuracy of the licensee's survey maps.
The results'of
the monitoring were found to be in close agreement with the licensee's
surveys.
No violations or deviations were identified.
5.
tiaintenance and Surveillance (61726 & 62703)
a.
Observations Of Work Activitin
Station maintenance and surveillance activities of both
safety-related and nonsafety-related systems and components listed
below were observed or reviewed to ascertain that they were
conducted in accordance with approved procedures, regulatory
guides, industry codes or standards, and in conformance with
technical specifications.
Document
& tivity
023534
Votes Testing of Valve 1SXO97A
D25008
Div I DG Output Breaker Inspection
D26498
Clean / Inspect Valve IE51-F068
D30476
Rebuild Horizontal Fire Pump
D31903
Repair Controller for valve IWS01818
D32476
Replace bearing on ISA01C Air Compressor
D33015
Replace valve IE51-F324A
D36798
Votes Testing of Valve IE12-F049
7911.35
Calibrate Alnor Dosimeters-
9080.01
Diesel Generator Operability Test
9404.02
Valve Stroke Timing IE51-F068, F077, F078
9433.16
RCIC storage tank level channel IE51-N035A
calibration
b.
Reactor Feedwater Pumo (RFP) Maintenance
The 8 RFP had been taken out of service to inspect the condition
of the bronze bushings in the throttle linkage. This was done as
part of the licensee's extensive efforts to resolve the problem
with the throttle linkage binding. The licensee had previously
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done extensive machining to repair the bushings and had committed
to inspect the condition of-the bushings after 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> of
operation (see Inspection Report 461/92012, Paragraph 4.c).
When
the throttle linkage was initially inspected, maintenance
personnel noted that the linkage was difficult to move by hand.-
Examination of the bushings showed accelerated wear and pitting of
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both the bushings and the steel journals.
The licenser. replaced
the bushings with new ones for both the A and B RfPs.
The unit was subsequently restarted on November 24, and with less
than 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> of service the B RFP throttle linkage again locked
up.
The pump was isolated without inducing a transient.
Examination of the bushings indicated severe galling and damage to
bushings and damage to the journals.
Based on the lack of success
in resolving the problems with the bushings, the licensee
replateu the bronze bushings with double tapered roller bearings.
This was ai m done for the A RFP.
The licensee initiated a failure analysis of the bronze bushings,
which was still in progress at the end of the inspection period.
After replacing the bushings in the A RFP the licensee experienced
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problems with the hydraulic control actuator for the throttle
linkagc. The problem had not been corrected by the end of the
report period and the inspectors will perform further evaluation
in a subsequent report on this problem and the results of failure
analysis.
c.
Service Air Comoressor Activitit:i
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The licensee rebuilt the ISA01C service air compressor (SAC) and
subsequently observed that the oil seal on the fourth stage failed
prematurely.
The licensee investigated this problem and
discovered that the manufacturer had improperly drilled a seal air
port hole in the fourth stage and that the hole was slightly
misaligned.
Maintenance personnel filled in the hole and drilled
a new
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The itcensee also inspected the bearings on the air compressor's
motor,
in the past, the licensee would repair the SAC after
problems were observed, return the SAC to service, and
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subsequently nocice that the motor bearings were damaged. This
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time the licensee inspected the motor bearings before the SAC was
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returned to service and discovered the outboard bearing was
damaged. The SAC was successfully returned to service.
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The inspectors noted excellent efforts of the maintenance and
engineering personnel in identifying the misdrilled seal air port
hole and the interrelationship between problems in the compressor
and the motor bearings.
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No violations or deviations were identified.
6.
Security
Etness for Duty Proaran)
The inspector reviewed the licensee's fitness for duty (ffD) records for
positive tests in the first half of 1992.
The records were complete and
provided information on the substance involved and actions taken by the
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licensee on the individual's access to Clinton station.
There was an
absence of documented information on whether impaired individuals, who
had access to the plant, had been involved with any safety-related
activities; and if so, was there any impact on those activities,
llowever, the FfD program manager had met with plant management in each
case and discusscd the impact,
in all of the cases, there was no impact
on safety related systems, structures, or components.
Following
discussion with the inspector, the licensee decided to document these
discussions and consolidate them with the other positive test
information.
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No violations or deviations were identified.
7.
[naineerina and Technical Suppgri
The inspectors reviewed the licensee's evaluation of the applicability
of HRC Information Notice (IN) 92-27, " Thermally Induced Accelerated
Aging and failure of ITE/Gould A.C. Relays used in Safety-Related
Applications."
The IN addressed using class J10 relays mounted in a
horizontal " ganged" arrangement.
The licensee reviewed the installation
for all class J relays and determined that Clinton had two instances of
normally energized class J13 relays, in a ganged configuration.
However, this arrangement had been tested by another utility and no
3roblems were identified.
The inspectors concluded that the licensee
lad expanded the scope of its analy:,;is beyond the requirements of the IN
and performed a thorough evaluatia.
The inspectors have no concerns on
this issue.
No violations or deviations were identified.
8.
Safety Assesignt and Ouality Verification
a.
Self Assessment Capability (40500)
The inspector reviewed a third-party audit of the quality
assurance (QA) organization.
The audit aapeared to be very
thoroigh and identified strengths and wea(nesses.
Findings from
the audit were as follows:
Several weaknesses were noted in the
quality engineering's inspection planning.
Strengths were noted
in the level of training of quality engineers and the niorning
turnover meeting.
Quality verification personnel were
knowledgeable of inspection progrsm requirements.
The audit recommended that the matrixes for the audit schedule,
Appendix B, and technical specifications be conse);o; ted to assure
proper coverage.
The licensee's response stated the its present
structure was adequate.
The certification of auditors was found
to be current and audit checklists were thorough and supported
audit findings.
Problems and concerns were properly identified on
condition reports or recommendations. The overall conclusion was
that the audit and surveillance program was effective in assessing
QA program implementation.
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However, problems were identified in procurement QA.
Procurement
document reviews were marginally adequate. The QA reviews did not
incit le drawings or specifications. The QA acceptance of items
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was ut. satisfactory.
The primary problem was a lack cf objective
evidence in support of testing / inspections required to demonstrate
the acceptability of items.
Contributing to this was a lack of
attention to detail.
This problem was most apparent in commercial
grade dedications. The licensee's response noted that this
problem had been identified earlier. The licensee concluded that
the previous corrective action had failed to resolve the problem
and was developing new corrective actions.
The inspectors will review this issue in a subsecuent report after
the licensee's corrective actions are implementec
and a followup
audit is performed.
b.
Licensee Event Report follqw-up (90712 & 92700)
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Through direct observation, discussions with licensee personnel,
and review of records, the following licensee event reports (LER)
were reviewed to determine that the reportability requirements
were fulfilled, immediate corrective action was accomplished, and
corrective action to prevent recurrence had been accomplished in
accordance with technical specifications.
LIB
Title
461/92001
Main Transformer "B" phase fault resulted in a
Turbine Trip and Reactor Scram.
461/92002
Reactor Feed Pump Control Lockup resulted in a
low Reactor Water Level Trip.
No violations or deviations were ide,itified.
9.
tLanagmquLlicetina
Mr. J. S. Ferry, Senior Vice President and members of his staff met with
Mr. A. B. Davis, Regional Administrator, and members of his staff on
November 10, 1992, at the Clinton Power Station. Topics incluJed
efforts to improve the corrective action and Generic Letter 89-10
programs, maintenance program performance, and the nuclear program
strategic plan.
10.
Unresolved Itemi
Unresolved items are matters about which more information is required in
order to ascertain whether they are acceptable items, violations, or
deviations.
One unresolved item disclosed during the inspection is
discussed in paragraph 2.b.
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[x 4 intfryftg
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t pectors met with the licensee representatives denoted in
pa. ; graph I at the conclusion of the inspection on December 7,1992.
The inspectors surnarized the purpose and scope of the inspection and
the finding;.
The inspectors also discussed the likely informational
content of the inspection report, with regard to documents or processes
reviewed by thi inspectors during the inspection.
The licensee did not
identify any such documents or processes as proprietary.
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