IR 05000298/1993012
| ML20035C808 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/30/1993 |
| From: | Powers D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20035C806 | List: |
| References | |
| 50-298-93-12, NUDOCS 9304090100 | |
| Download: ML20035C808 (11) | |
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APPENDIX
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U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Inspection Report:
50-298/93-12 Operating License: DPR-46 Licensee:
Nebraska Public Power District P.O. Box 499 Columbus, Nebraska 68602-0499 Facility Name: Cooper Nuclear Station Inspection At: Brownville, Nebraska Inspection Conducted: March 9-12, 1993 Inspectors:
L. E. Ellershaw, Reactor Inspector, Maintenance Section, Division of Reactor Safety L. D. Gilbert, Reactor Inspector, Maintenance Section', Division of Reactor Safety Approved:
d 4' < M 43/36/93
Dr. Dale A. Powers, Chief, Maintenance Section Date Division of Reactor Safety Inspection Sumary Areas Inspected: Routine, announced inspection of. inservice inspection activities, followup of licensee event reports, and other followup.
Results:
The inservice inspection program was effectively implemented, with
performance of nondestructive examinations observed to be good (Section 2.1.1).
The repair and replacement program was effectively implemented, with
performance of work activities observed to be good (Section 2.1.2).
The nondestructive examinations were performed by contract personnel
that were well qualified for the process (paragraph 2.2).
Summary of Inspection Findinas:
Unresolved Item 298/9223-01 was reviewed, but not closed (Section 3).
- 9304090100 930405 PDR ADOCK 05000298 G
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Licensee Event Reports91-018, 91-019, and 92-018 were closed
(Section 4).
Attachment:
Attachment - Persons Contacted and Exit Meeting
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DETAILS i
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1 PLANT STATUS
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During this inspection period, the plant was in a refueling outage.
l 2 INSERVICE INSPECTION - OBSERVATION- (73753)
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The objectives of this inspection were to ascertain whether performance of
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inservice examinations, repair, and replacement of Class 1, 2, and 3 pressure -
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retaining components were performed in accordance.with the Technical i
Specifications, the applicable ASME Code, correspondence between NRR and the o
licensee concerning relief requests, and requirements imposed by NRC and i
industry initiatives.
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2.1 Discussion
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.i 2.1.1 Inservice Inspection Activities
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The inspectors reviewed, "CNS 2nd Ten Year _ Inservice. Inspection Program for ASME Class 1, 2 and 3 Components," Revision 3 and_the 1993 Addenda to
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Revision 3, and verified that the observed examinations were accomplished as j
scheduled for the current-inspection period. The inservice inspection-
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examinations scheduled for the current outage. were _ documented in the "CNS-Spring 1993 Outage Examination Plan," Revision'2. The inspectors noted that j
changes to the inservice _ inspection program and outage examination plan and
schedules were accomplished in accordance with engineering department
.i instructions documented in Procedure ED93-01, " Inservice Inspection' Program-l
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Implementation," Revision 0.
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From the examinations scheduled, the inspectors observed portions -of, the
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magnetic particle and ultrasonic _ examinations of a' Class 1 piping weld in' the.
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reactor core isolation cooling system, Weld RWA-BJ-6,- and the liquid penetrant l
examination of an integral attachment to Class 1 piping in the reactor feed
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system, Weld CWB-BKl-6. The magnetic particle examination was performed using j
Procedure GE-MT-100, " Procedure for Magnetic Particle Examination,"
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Revision 0, and approved Field Revision Request NPPD-91-25. The ultrasonic t
examination was performed using Procedure GE-UT-106, " Procedure for Manual-Ultrasonic Examination of Pressure Retaining Welds in Ferritic and Austenitic Piping and Components," Revision 1, and approved Field Revision Requests NPPD-91-08 and NPPD-91-37. The liquid penetrant examination was
performed using Procedure GE-PT-100, " Procedure for Liquid Penetrant-i Examination," Revision 0, and' approved Field Revision Request NPPD-91-27.
t For these examinations, the inspectors verified that: -the examinations were l
performed by personnel certified as Level 11 examiners for the applicable i
method, the equipment used was calibrated, the system calibration was
performed prior to using the transducer for the ultrasonic examination, the l
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temperature of the components and calibration block were within the limits
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specified in the applicable procedure, the penetrant materials were
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appropriately certified,. and the applicable examination techniques were i
consistent with the procedure used for the examination. The examinations were
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performed satisfactorily and no indications requiring evaluation were observed
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or reported.
For the nondestructive examination of piping supports, the inspectors observed the visual examination of a pipe support for the main steam system,
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Support MS-H152. The visual examination was performed using
Procedure GE-VT-100, " Procedure for VT-3 Examination," Revision 0, and
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approved Field Revision Requests NPPD-91-29 and NPPD-91-36; and Procedure V4-W812. " Procedure for VT-4 Visual Examination," Revision 2, and approved Field Revision Requests NPPD-91-31 and NPPD-91-34. The examination was performed satisfactorily by a Level II examiner certified for performing the VT-3 and VT-4 examinations. The visual examiner identified two items that did not conform to Support Drawing MS-H152, Revision N01, which pertained to the specified cold-load setting of the spring support and the double nutting of stud bolts in the support base plate. The two nonconforming conditions were documented in Report R-043 for NPPD engineering evaluation and i
disposition.
The inspectors reviewed the qualifications and certifications of all nondestructive examination personnel involved in the performance, evaluation,
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and supervision of the inservice inspection activities observed during the
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inspection. The inspectors were provided satisfactory personnel certifications for the appropriate level of qualification for each method of-nondestructive examination. The certifications also documented a satisfactory
annual visual acuity and color test for each of the nondestructive examination personnel. The certifications were found to be current and consistent with
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the requirements of Procedure FQP-03, " Procedure for Qualification and l
Certification of Nondestructive Examination Personnel," Revision 04.
i 2.1.2 Section XI Repair and Replacement The inspectors reviewed three repair and replacement activities associated with a leak in a drain line of the residual heat removal system, a
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modification of piping supports in the main steam piping system, and a leaking residual heat removal system valve bonnet.
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The residual heat removal drain line leak was documented in Nonconformance
Report 93-027 and Maintenance Work Request 93-0855. The inspectors observed i
the section of piping that was prefabricated to replace the leaking 2-inch
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drain line. The maintenance. work request included a completed repair and replacement plan, a modified piping design, a completed weld checklist, a nondestructive examination report, and special instructions for the-replacement of a section of the Class 2 drain line.
The main steam pipe support modification was documented in Design Change 88-3028, Amendment 1, and Maintenance Work Request 93-0419. The i
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inspectors observed the cutting and quality control verification of material traceability marking of the tube steel, lugs, and plate prefabrication of a new pipe support for a 3-inch, Class 2 main steam line. The maintenance work request included a completed repair and replacement plan and related documentation for the fabrication and installation of Support MS-H241.
The leaking residual heat removal valve bonnet was documented in Maintenance Work Request 92-2409. The inspectors reviewed the maintenance work request, which corrected the leaking bonnet on Valve RHR-CV-CVl9. The maintenance work
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request included a completed repair and replacement plan, a completed maintenance procedure for replacing the bonnet gasket and bonnet bolting, a post-maintenance testing checklist, and a completed inservice leak test record.
The repair and replacement activities were well documented and included notification of the Authorized Nuclear Inservice Inspector as required by CNS Procedure 0.30, "ASME Section XI Repair / Replacement and Temporary Non-Code
Repair Procedure," Revision 5.
2.2 Conclusions The inservice inspection and repair and replacement programs were effectively
implemented, with performance of work activities and nondestructive examinations observed to be good. The nondestructive examinations were performed by contract personnel that were well qualified for the process.
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3 FOLLOWUP (92701)
(OPEN) Unresolved item 298/9223-01:
Timeliness and Effectiveness of Corrective Actions Associated With Local Leak Rate Test Failures of Individual
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Feedwater Valves and Effects on Primary Containment System Intearity.
NRC Inspection Report 50-298/92-23 documented that there had been a number of local leak rate test failures involving four feedwater system check valves (RF-CV-13CV, -14CV, -15CV, and -16CV). These failures contributed to the
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primary containment system exceeding its allowable leakage rate (.6La).
Each occurrence had resulted in the issuance of a nonconformance report and a licensee event report, which documented the failures.
Each occurrence had caused initiation of corrective actions which, by themselves, did not appear to be effective.
Nonconformance Report 2296, dated September 1983, and Licensee Event
Report 83-013, documented feedwater check valve local leak rate test failures and corrective actions, which included installation of soft
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seats and the implementation of an annual trending review by
engineering.
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i Nonconformance Report 4510, dated August 1985, and Licensee Event
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Report 85-005 documented feedwater check valve local leak rate test failures'and corrective actions, which included soft-seat replacement, continued trending, and initiation of preventive maintenance activities.
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Nonconformance Report 4905, dated January 1987, and Licensee Event
Report 87-004 documented feedwater check valve local leak rate test failures and a corrective action, which increased the frequency of preventive maintenance from once every 3 years to once each refueling
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t outage.
Nonconformance Report 91-092, dated October 1991, and Licensee Event
Report 91-020 documented a detailed iiistorical review of penetration leakage data, which revealed chronic failure of Penetrations X-9A (Feedwater Check Valves RF-CV-15CV and -16CV) and X-9B (Feedwater Check Valves RF-CV-13CV and -14CV), without regard for the various modifications performed over the years (addition of soft seats and hinge pin modifications). The nonconformance report requested engineering to perform a detailed evaluation of the feedwater check valve failures, including the establishment of causes and preventive measures.
In response.to the last nonconformance report, engineering provided a final
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written report on September 25, 1992, in which the results of a survey of other boiling water reactor facilities were discussed. Based on the survey
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results and a review of all maintenance history applicable to the feedwater check valves, the following recommendations were made:
Initiate a change to the feedwater check valve preventive maintenance
items, which would require notification to the system engineer prior to performing preventive maintenance to allow for a detailed examination and evaluation of all internal components of the check valves.
Initiate an engineering work request to install high point vents to
provide an adequate vent path during system drsining.
(Prior to performing a local leak rate test, piping downstream of the feedwater check valves was drained. This created a vacuum and, since no high point vent path existed, the vacuum appeared to be relieved by unseating the valves. This could have resulted in an unacceptable local leak rate
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test.)
Initiate an engineering work request to remove the soft-seat rings,
which were not part of the original design.
(The soft-seat rings have been found to bc degraded following valve maintenance and have contributed to the unacceptable local leak rate test results.) Also included in the discussion, was disc / seat / hinge pin bore alignment, which is the process by which required alignment and machining is-performed in-situ and in one setup'to provide the ultimate alignment and
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disc / seat fitup (considered to be crucial for achieving acceptable local leak rate test results).
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The preventive maintenance changes have been initiated and were scheduled to be implemented during the current refueling outage (Refueling Outage 15),
which was initiated on March 5, 1993. Both engineering work requests (92-125.
and 92-126) were approved by the plant manager on October 13, and 22,1992,.
respectively. Both were scheduled to be implemented during the 1994 outage; however, it was recommended by the plant manager, in the comments section, that Engineering Work Request 92-125 (installation of high point vents) be strongly considered for implementation during Refueling Outage 15.
On December 11, 1992, the leak rate test engineer issued a letter, which addressed the results of an engineering review of testing sequences.
Engineering had noted that certain testing sequences (e.g., the performance of
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the required inservice full-flow test prior to local leak rate testing) could have an adverse affect on local leak rate test results.
It was determined that in order to obtain truly as-found local leak rate test results, then the performance of the full-flow test should be performed subsequent to the local
1eak rate test. The leak rate test engineer discussed this information with the outage planning group and the inservice test engineer to arrange a different sequence.
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During this inspection, the inspectors verified that each of the preventive maintenance activities (i.e., 00295, 00296, 00297, and 00298) applicable to -
each of the four feedwater check valves had been revised to require notification to the system engineer prior to performing any work. The inspectors also reviewed the outage schedule and verified that the test
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sequences had been revised.
The site. manager, on March 11, 1993, informed the inspectors that a modification package was being prepared for implementation during this refueling outage to install high-point vents and low-point drain lines to facilitate draining down the feedwater system during future outages.- The site
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manager also stated that the modification would require post-maintenance testing (i.e., performance of local leak rate tests on the feedwater check valves subsequent to the flooding and draining down of the feedwater lines).
Prior to this inspection, the licensee drained down the feedwater system and
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then initiated the local leak rate tests on the four feedwater check valves.
The drain down methodology has now been changed in an effort to minimize any disturbance to the valves' discs prior to the local leak rate testing. At the beginning of this inspection, the inspectors were informed that the valves failed and the 1Mensee was unable to quantify the test results because of gross leakage. At the conclusion of this inspection, the licensee presented
to the inspectors a preliminary action plan regarding the proposed testing and repair of the feedwater check valves. Due to the preliminary nature of the action plan, the licensee agreed to keep the NRC resident inspectors cognizant of action item and schedule status, in order to provide ample opportunity for URC followup.
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4 ONSITE REVIEW OF LICENSEE EVENT REPORTS (92700)
4.1 (Closed)
Licensee Event Report 298/91-018: -Failure of a 4160V Circuit Breaker to Trio Due to Stickina Trio Latch Roller Mechanism Caused by Hardened Lubrication On March 23, 1991, a General Electric Company 4160V circuit breaker,
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Model AMH-4.76-250-10, failed to open when the control switch was actuated.
Upon inspection, it was determined that the trip latch roller would not rotate freely. This problem was considered to be similar to three previous 4160V.
breaker deficiencies that had been identified in 1987.
Investigation at that time revealed that the petroleum-based lubricant specified by General Electric tended to dry out and " seize" the operating mechanism after long-term exposure
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to excessive heat and infrequent operation. Corrective actions taken at that
time included increasing the preventive maintenance (inspect and add i
lubricant) frequency from every two cycles to every cycle.
In addition, modifications were made to ventilation systems that significantly reduced ambient temperatures in the switchgear rooms. The licensee also contracted with General Electric, in September 1989, to disassemble, inspect, and refurbish all safety-related 4160V circuit breakers.
At the time of the most recent occurrence, these activities had been completed on 10 of the 24 safety-related breakers.
Since a refueling outage was in process, the licensee decided not to delay further refurbishment. All 4160V breakers, which had not been refurbished by General Electric, were disassembled to enable removal of the trip latch and cam follower rollers.
The assemblies were cleaned, relubricated, and reassembled.
In addition, the preventive maintenance activities were enhanced by adding the requirement to disassemble and clean to assure that all old lubricant was removed prior to adding new lubricant. These requirements became Section 8.4 in Revision 11 to Maintenance Procedure 7.3.17, " General Electric 4160V Breakers, Maintenance, Testing, and Setting," dated October 29, 1992. Attachments 2 and 3 of the procedure identified all affected essential and nonessential 4160V breakers.
The performance of Section 8.4 is to be documented in Attachment 5 to the procedure, " Cleaning and Lubrication Guide.
The inspeuors verified that the procedure had been revised to incorporate
these requirements and, by review of documentation, that the remaining 4160V breakers not sent to General Electric had been disassembled, cleaned, and relubricated.
It appeared that the above actions should eliminate any further breaker malfunctions attributed to lubrication problems.
4.2 (Closed) Licensee Event Report 298/91-019:
Actuation of Shutdown Coolina Isolation Valves While Performina the Containment Intearated teak Rate Test
This event occurred on December 9, 1991, during a refueling out te and was the result of a momentary pressure transient caused by the starting of the residual heat removal pump while the primary containment was pressurized for the performance of the integrated leak rate test. Normally, the residual heat
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removal pump would have been operating; however, the pump had been secured in order to eliminate background noise to facilitate the location of leakage pathways by test personnel using sonic detection equipment. During past
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performances of the integrated leak rate test, it had not been necessary to secure the operating residual heat removal pump to identify leakage paths.
Since the combined effect of the pump start pressure transient with integrated leak rate test pressure was not anticipated, the procedure governing the performance of the integrated leak rate test did not provide guidance on the
potential for pressure transients causing actuation of the shutdown cooling isolation valves.
The licensee committed to process a procedure change to provide guidance to prevent actuation of the shutdown cooling isolation valves should it be necessary to start a residual heat removal pump in the shutdown cooling mode while the containment is pressurized during an integrated leak rate test.
The inspectors reviewed Procedure 6.3.1.3, " Primary Containment Integrated Leak Rate Test," Revision 13, dated December 29, 1992, and verified that necessary notes and appropriate steps had been incorporated to account for and control the starting of a residual heat removal pump while the primary containment is pressurized.
It appeared that this revision would preclude the initiation of a pressure transient which would cause actuation of the shutdown cooling isolation valves.
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4.3 (Closed) Licensee Event Report 298/92-018: HPCI. RCIC and SLC Systems Declared Inocerable Due to Missed ISI Functional Inspections of Pumo Suction Pipina On December 17, 1992, while at full power, the high-pressure coolant injection, reactor core isolation cooling, and the standby liquid control
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systems were declared inoperable because of missed inservice inspections of portions of these systems (ASME Section III, Class 3 piping) as required by Section XI of the ASME Code.
The missed inspections were identified during the licensee's third party review of the inservice inspection program, which was being performed in response to deficiencies identified in the program. The third party review identified that neither the inservice inspection program plan nor the
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examination plan specified the frequency of system pressure tests for ASME Code,Section III, Class 3 piping. This resulted in system functional tests of portions of the high-pressure coolant injection, reactor core isolation cooling, and the standby liquid control systems, not being scheduled or performed. The systems were declared inoperable until the required system functional tests could be performed. Approximately 1 1/2 hours later, the tests were successfully conducted and the systems were declared operable. The licensee stated that although the systems were declared inoperable, they remained inservice and were capable of performing their required functions..
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As noted above, the third party review was initiated.as corrective action to identified deficiencies in the inservice inspection program. One of these deficiencies was similar in nature to an issue that was identified as a non-cited violation in NRC Inspection Report 50-298/91-26.
The inspectors verified that the third party review of the inservice inspection program had been completed and all identified changes were incorporated into the January 1993 Addenda to Revision 3 of the inservice inspection program. The Addenda was also reviewed and accepted by the Authorized Nuclear Inspector in a memorandum dated February 15, 1993, as being i
within the requirements of the 1980 Edition, Winter 1981 Addenda of Section XI
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ATTACHMENT l
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1 PERSONS CONTACTED i
1.1 Nebraska Public Power' District '
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- L. Bray, Regulatory Compliance Specialist
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- P. Ballinger,L0perations Engineering Supervisor
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- B. Crow, Lead Mechanical Engineer.
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- M. Dean, Nuclear Licensing and Safety Supervisor
- J. Flaherty, Engineering Manager
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- S.-Freborg, Plant Engineering Supervisor
- R.-Gardner, Plant Manager
- G. Hicks, Jr., Inservice Inspection Engineer
- J. Meacham, Site Manager
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- C. Moeller, Technical-Staff Manager
- G. Smith, Quality' Assurance Manager
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- M. Spencer, Engineering Programs. Supervisor
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1.2. HEC
- W. Walker, Resident Inspector In addition to the personnel listed above, the inspectors contacted other_
licensee employees during this inspection' period.
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- Denotes personnel attending the exit meeting.
o 2 EXIT MEETING
An exit meeting was conducted on March 12, 1993. During this meeting, the
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inspectors reviewed the scope and findings of the report. 'The licensee.did '
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not identify as proprietary, any information provided to,. or reviewed' by. the
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inspectors.
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