IR 05000456/1993020
| ML20057D662 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 09/29/1993 |
| From: | Farber M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20057D661 | List: |
| References | |
| 50-456-93-20, 50-457-93-20, GL-93-04, GL-93-4, NUDOCS 9310050143 | |
| Download: ML20057D662 (11) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-456/93020(DRP); 50-457/93020(DRP)
Docket Nos. 50-456; 50-457 Licenses No. NPF-72; NPF-77
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Licensee: Commonwealth Edison Company
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Opus West 111 1400 Opus Place Downers Grove, IL 60515 Facility Name:
Braidwood Stction, Units 1 and 2
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inspection At:
Braidwood Site, Braidwood, Illinois Inspection Conducted: July 10 through September 10, 1993 Inspectors:
S. G. Du Pont E. R. Duncan T. J. Kobetz J. D. Smith
Approved By:
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M. J. Farbst, Chi'e f
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Date Reactor Pr%jects Section l A Inspection Summary inspection from July 10 throuch Seoterber 10.1993 (Reports No. 50-456/93020(DRP): 50-457/93020(DRP))
Areas Inspected:
Routine, unannounced safety inspection by the resident inspectors of licensee event report review; Generic Letter 93-04; engineered safety feature system walkdown; temporary alterations; operational safety r
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verification; monthly maintenance observaticn; monthly surveillance observation; report review and reetings.
Results: No violations or deviations were identified.
Maintenance, Operations, System Er.gineering, and Radiological Protection
departments formed ef fective teams to reduce the amount of dose
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associated with replacing the residual heat removal pump motor. The use
of ALARA planning and designating low dose areas were instrumental in performing the task with as low a dose as possible.
System Engineering was effective in their troubleshooting efforts of the
residual heat removal pump. Troubleshooting was difficult due to the j
internal design of the bearing oil reservoir.
Teamwork between System Engineering, the vendor, and Site Engineering was effective.
j 9330050143 930929 EI PDR ADOCK 05000456 P
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Station management demonstrated good safety judgment in replacing the
residual heat removal pump motor. Although all pump parameters were
within normal specifications during the pump runs, management rightly l
chose to replace the motor based upon the uncertainties associated with the degraded conditions of the oil in the reservoir.
I The two events associated with the Unit 2 residual heat removal pump and
station fire pumps represented two different approaches by station personnel.
In the case of the residual heat removal pump; appropriate planning, management involvement, and teamwork existed that demonstrated a good conservative safety approach. However, during the same period,
these attributes were not evident with the activities associated with the fire prevention system.
Station management became involved and effectively directed the efforts associated with the fire pumps.
This resulted in determining the actual failure mechanism of the pumps.
i Station personnel did an excellent investigation of the root causes
associated with both events.
Because of these efforts, appropriate
lessons-learned and corrective actions were developed and implemented.
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A non-cited violation associated with the Unit 2 residual heat removal
pump being inoperable is described in paragraph 6.
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DETAILS
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1.
Persons Contacted
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Commonwealth Edison Comoany (Ceco)
S. Berg, Vice President
- J. Achterberg, Executive Assistant
- K. Kofron, Station Manager T. Schuster, Acting Support Services Director
- A. Haeger, Regulatory Assurance Supervisor R. Kerr, Engineering and Construction Manager
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- D. Cooper, Operations Manager
- G. Groth, Maintenance Superintendent
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- R. Byers, Work Control Superintendent
- D. Miller, Technical Services Superintendent
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- K. Bartes, Quality Verification Superintendent i
A. Checco, System Engineering Supervisor S. Roth, Security Supervisor
- T. Pendergast, Regulatory Assurance
- B. Acas, SEC Group Leader
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- D.
Saccomondo, NLA
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- Denotes those attending the exit interview.
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The inspectors also interviewed several other licensee employees.
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2.
Licensee Event Report (LER) Review (92700)
f The following LERs were reviewed and closed based on the-following
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criteria:
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Reportability requirements were met.
- Immediate corrective actions were accomplished.
- Corrective act).'ns to prevent recurrence have been or will be
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initiated per technical specifications.
i (Closed) 457/93006:
Operation of Unit 2 RH Pump With Inadequate Oil
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Supply Due to Clogged Orifice. The details of the inspection are
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discussed in Paragraph 6 of this report.
I No violations or deviations were identified.
3.
Generic Letter Followup (92703)
l The inspector reviewed the licensee's compensatory actions associated with Generic Letter 93-04, " Rod Control System Failure and Withdrawal of I
Control Cluster Assemblies." The actions include the following:
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Every outage the licensee performs a control rod checkout.
- Every other outage Westinghouse performs enhanced card
maintenance.
The system engineer notified the Operations Manager, in writing,
of the control rod system problems.
Provided additional operator training on the control rod system
problems.
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The inspector also observed Ceco and Westinghouse engineers attempt to recreate the Salem event in which the one control rod withdrew in
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shutdown Bank A with an insert signal to the rods. The engineers were only able to partially recreate the event.
In lieu of a single control rod moving, the entire bank would move.
4.
Enaineered Safety Feature System Walkdown (71710)
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The inspector performed a detailed walkdown of the accessible portions of the Unit I and Unit 2 auxiliary feedwater systems and verified that the systems were aligned properly and, based on field observations, were operable.
The walkdown included the following:
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Verification that valves in the flow path were in the correct
position as required by procedure and that power, if required, was available; that valves were locked as appropriate; and that local
and remote position indications were functional and indicated the same values.
Verification that support systems essential to system actuation or
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performance were operational.
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Verification of proper breaker positions at local electrical
boards and indications on control boards.
Identification of equipment conditions and items that might
degrade plant performance.
Some minor housekeeping discrepancies were identified which the licensee j
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promptly corrected.
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No violations or deviations were identified.
5.
Temporary Alterations (37700)
The inspector reviewed the following temporary alterations:
93-1-001 93-1-004 i
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The inspector identified a discrepancy with 93-1-001. The 10 CFR 50.59
. Safety Evaluation referenced the Unit 2 Main Steam Isolation Valve bypass valve, 2MS1010, as the affected component in lieu of the Unit I valve. This discrepancy, by itself, has minor safety significance, but shows a lack of attention for detail in both preparing and reviewing the safety evaluation.
No violations or deviations were identified.
6.
Operational Safety Verification (71707)
The inspectors _ verified that the facility was being operated in conformance with the licensee's and regulatory requirements and that the licensee's management control system was effectively carrying out its responsibilities for safe operation.
The inspector performed plant tours to observe radiation control practices, housekeeping practices, and the general material condition of the plant.
In general, both housekeeping and material condition of the site were good. The inspector did identify concerns with radiation controls in the Unit 2 condensate pump pit and in the auxiliary building. The licensee promptly corrected the inspectors concerns.
The following activities were observed, evaluated, or reviewed:
Activities associated with the Unit 2
Pump.
Activities associated with the station fire pump.
- 2A Residual Heat Removal (RH) Pump During the last Unit 2 refueling outage, water was discovered in the 2A RH pump lubricating oil. The oil was drained and replaced on April 21, 1993.
The System tngineer requested a second oil change as a precautionary measure and continued troubleshooting efforts. The second oil change was accomplished on June 28, 1993, prior to the regularly scheduled ASME surveillance. However, when the oil drain plug was removed, only a small amount of oil came out of the drain. The oil sight glass was observed to contain the normal full level of oil.
The System Engineer and the Operations Department were informed of the inability to drain the oil.
It was decided to perform the scheduled ASME surveillance and to monitor bearing temperatures and vibration. The pump was run for approximately one hour during the surveillance. All pump parameters were observed to be normal. The System Engineer continued to troubleshoot the pump and contacted the vendor for assistance.
Initially, it was believed that the oil drain line was plugged and that the pump was operable.
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i On Ju h 26, 1993, the pump was taken out-of-service in preparation for
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unplug.ng the drain line and changing the oil. All attempts to unplug the oil drain line and to drain the oil reservoir were unsuccessful.
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During this process, it became apparent that the obstruction existed _in
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an orifice located internally and upstream of the bearing reservoir.
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The System Engineer developed and performed a~ test which proved that the
oil drain was not plugged.
.i Air pressure was applied to the bearing oil reservoir and a quantity of f
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thick oily material was removed.
Several oil flushes were conducted after the obstruction was cleared.
Oil samples were provided for I
analysis on July 28. This analysis subsequently determined that the bearing was not damaged.
On July 29, 1993, station management decided to conservatively replace the pump motor based on the visual condition of the oil samples. The
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2A RH pump motor was replaced on August 1, 1993. The motor was visually inspected on August 5, 1993, and found to have only slight discoloration i
of the bearing retainer ring. Although the pump parameters were normal
during the surveillance and the motor bearing was not damaged, station
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management declared the pump inoperable since April 21, 1993.
This is a violation of Technical Specification.
Since this was self-identified, appropriate corrective actions were taken in a timely
measure, and the System Engineer and station management took actions i
that were conservative and in ar, approach for safety, this is considered to be a non-cited violaticri per 10 CFR 2, Appendix C, Section V.A.
The inspector observed several aspects of the event and noted good
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teamniork and an approach for safety.
The following were noted:
l Maintenance, Operations, System Engineering, and Radiological-
Protection departments formed effective teams to reduce.the amount
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of dose associated with replacing the residual heat removal pump motor.
The use of ALARA planning and designating low dose areas i
was instrumental in performing the task with as low a dose as possible.
System Engineering was effective in their troubleshooting efforts
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of the residual heat removal pump. Troubleshooting was difficult due to the internal design of the bearing oil reservoir.
Teamwork
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between System Engineering, the vendor, and Site Engineering was effective.
Station management demonstrated good safety judgment in replacing
the res dual heat removal pump motor. Although all pump
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parameters were within normal specifications during the pump runs, management rightly chose to replace the motor based upon the uncertainties associated with the degraded conditions of the oil in the reservoir.
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Station Fire Pumo
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month surveillance on the station diesel-driven fire pump and associated.
I During April and May 1993, preparations were taken to perform the 18-
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support systems.
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On June 20, 1993, an alarm for icw differential pressure (Delta P) on l
the 2A Circulating Water (CW) pump was received in the control room.
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Normal pump parameters were verified and a normal zero Delta P was found across the travelling screens. This condition required verification of i
the water level in the intake bay. An Equipment Attendant verified that i
water existed in the bay. However, it was not recognized that the level
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was 12 to 15 feet low because of the lack of level marks and measuring devices.
The CW pump was believed to be operable.
Later, the fire pump was taken out-of-service for the surveillance.
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On June 21, 1993, another alarm was received for low Delta P on the i
2A CW pump. Again all pump parameters were normal and the Delta P
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across the screen was normal.
Since it was known that the 2A CW pump
had a degrading impeller and was scheduled for replacement later in the Fall of 1993, action was delayed until the System Engineer returned on June 23.
Also on June 21, 1993, replacement of the fire pump's battery was delayed.
Three replacement batteries were drawn from the storeroom.
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None of these would take a charge. This required purchasing a
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replacement battery direct from the vendor.
The remainder of the fire pump surveillance was initiated. These activities consisted of a basic
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overhaul of the aiesel motor. However, these activities were also delayed because of the lack of parts in the storeroom and insufficient paperwork for electrical maintenance to determinate the installed j
batteries.
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On June 22, 1993, the batteries were de-terminated and the required parts were obtained from the Byron Station.
j On June 23, 1993, control room operators noticed that the fire header l
pressure was low and the "0A" jockey fire pump could not maintain j
pressure.
A second jockey pump was started and troubleshooting was l
initiated on the OA jockey pump.
On June 28, 1993, Operations requested the starting of the motor driven i
fire pump to support fire brigade training. The electrical motor driven j
pump failed to develop the required discharge head.
The pump was
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secured and declared inoperable. Repairs were delayed to continue the maintenance on the diesel driven pump, since those activities could be l
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completed before the maintenance on the motor driven pump.
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Later on June 28, 1993, the diesel driven pump maintenance activities were completed.
Simultaneously, the 0A jockey pump was foun'd to' have its impeller uncoupled from the motor shaft.
The pump was removed and
replaced with a pump from the Byron Station.
l-On June 29, 1993, the valve adjustment on the diesel driven pump was found to have been done incorrectly. The valves were properly l
readjusted.
l The Operations Department subsequently crosstied the fire header to the Unit 2 service water (SX) system.
This action removed the
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administrative action requirement entered on June 28 when the diesel l
driven and motor driven pumps were out-of-service.
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Later on June 29, 1993, the diesel driven pump was successfully tested and all administrative requirements were exited. On June 30, 1993, the
OA jockey pump was returned to service and maintenance began on the i
motor driven pump. On July 1, 1993, the motor driven pump was tested j
after the completion of maintenance. However, the pump failed to
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develop flow or discharge pressure. The intake bay water level was
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found to be only about one foot above the motor driven fire pump
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suction. The Operations Department was notified and the 2A CW pump was immediately shut down.
The motor and diesel driven fire pumps take a suction off the same intake bay as the 2A CW pump. -After the 2A CW pump was secured, the level in the bay returned to normal.
Troubleshooting found that the travelling screens were plugged and the OA jockey fire pump impeller stack was leaning against one of the screens. Additionally, an air leak was discovered on the high side of the Delta P/ level transmitter. This produced a false normal Delta P.
l The screens were cleaned of watergrass and the transmitter was repaired.
Later on July 1,1993, the intake bay level was returned to normal, and the CW and the fire protection systems were restored to normal.
The licensee's lessons-learned investigation of activities associated with the fire pump identified several important factors:
Planning of the maintenance with the fire pumps did not adequately
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The Diesel Driven Fire Pump was taken out-of-service about 23
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l hours prior to the actual work on the pump.
The intake bay water level was not marked and prevented an
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accurate assessment of the roct cause for the pump failures.
Alarm response and troubleshooting activities did not initially i
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verify the operability of the Delta P transmitter.
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Troubleshooting activities did not initially verify the
operability of the travelling screens.
The Diesel Driven Fire Pump's batteries were stored for long
periods in a wet condition without maintaining an active maintenance charge.
This condition prompted accelerated aging and prevented the batteries from receiving a full electrical charge.
Conclusions These two events represented two different approaches by station personnel.
In the case of the residual heat removal pump; appropriate planning, management involvement, and teamwork existed, that demonstrated a good conservative safety approach. However, during the same period, these attributes were not evident with the activities associated with the fire prevention system.
Station management became involved and effectively directed the efforts associated with the fire pumps.
This resulted in determining the actual failure mechanism of the pumps.
Separate from these activities, station personnel did an excellent investigation of the root causes associated with both events.
Because of these efforts, appropriate lessons-learned and corrective actions were developed and implemented.
Implementation of all corrective actions was verified by the inspector with the exception of developing a scheme for verifying intake bay level s.
This corrective action is currently being reviewed by station
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management and will require extensive planning to overcome certain difficulties. These difficulties include seismic and security safeguard requirements.
Resident and regional inspectors will review the final corrective
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actions for compliance to both seismic and safeguards requirements during subsequent inspections.
One non-cited violation was identified.
7.
Monthly Maintenance Observation (62703)
Routinely, station maintenance activities were observed and/or reviewed by the inspectors to ascertain that they were conducted in accordance with approved procedures, regulatory guides and industry codes or standards, and in conformance with technical specifications.
The following items were also considered during this review:
approvals were obt ained prior to initiating the work; functional testing and/or calibrations were performed prior to returning components or systems to service; quality control records were maintained; and activities were accomplished by qualified personnel.
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- The cctivities' associated with maintenance on the Unit'2 Residual Heat Removal and : Station Fire Protection Systems are discussed in the details of Paragraph 6.
No violations or deviations were identified.
8.
Monthly-Surveillance Observation (61726)
The inspectors observed several of the surveillance tests required by technical specifications during the. inspection period and verified that testing was performed in accordance with adequate procedures.
The inspector independently verified that test instrumentation was calibrated, that ' test results conformed with technical specification and procedure requirements, and the results were reviewed. - No violation or deficiencies were identified during the testing.
The following surveillance activities were observed and reviewed:
2BwVS 6.2.1.b-1, "ASME Surveillance Requirements for A Containment Spray Pump and Check Valves _CS003A, _CS011A" No violations' or deviations were identified.
9.
Report Review During the inspection period, the inspector reviewed the licensee's Monthly Performance Report for July 1993. The inspector confirmed that the information provided met the requirements of-Technical Specification-6.9.1.8 and Regulatory Guide 1.16.
The inspector also reviewed the licensee's Monthly Plant Status' Reports for May and June 1993.
No violations or deviations were identified.
10.
Violations for Which A " Notice of Violation" Will Not Be Issued The NRC uses the Notice of Violation as a standard method for formalizing the existence of. a violation of a legally binding requirement. However, because the NRC wants to encourage and support licensee's initiatives for self-identification and correction of problems, the NRC will not generally issue a Notice of' Violation for a violation that meets the tests of 10 CFR 2, Appendix C, Section V.A.
These tests are:
1) the violation was identified by the licensee; 2)
the. violation would be categorized as Severity Level IV or V; 3) the violation will be corrected, including measures to prevent recurrence, within a reasonable time period; and 4) it was not a violation that could reasonably be expected to have been prevented by the licensee's corrective action for a previous violation. A violation of regulatory requirements identified during this inspection for which a Notice of Violation will not be issued is discussed in Paragraph 6.
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11.
Exit Interview (30703_1
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The inspectors met with the licensee representatives denoted in
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Paragraph I during the inspection period and at the conclusion of the inspection.- The inspectors summarized the scope and results of the-
inspection'and discussed the likely content of.this inspection report.
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The licensee acknowledged the information and did not indicate that any
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of the information disclosed during the inspection could be considered.
proprietary in nature.
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