ML20133F545
| ML20133F545 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 12/31/1996 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20133F538 | List: |
| References | |
| 50-424-96-11, 50-425-96-11, EA-96-479, NUDOCS 9701140258 | |
| Download: ML20133F545 (31) | |
Text
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NOTICE OF VIOLATION Georgia Power Company Docket Hos. 50-424 and 50-425 Vogtle Electric Generating Plant License Nos. NPF-68. NPF-81 EA 96-479 During an NRC inspection conducted on September 29 through November 9.1996.
violations of NRC requirements were identified. In accordance with the
! " General Statement of Policy and Procedures for NRC Enforcement Actions." <
l NUREG-1600, the violations are listed below: '
A. Technical Specification (TS) 3.5.2 Limiting Condition for Operation.
Emergency Core Cooling System (ECCS) Subsystems - T m Greater than or Equal to 350 F. recuires that two inde]endent ECCS subsystems be operable when in moces 1. 2. or 3 Eac1 subsystem is comprised of one l operable centrifugal charging pump. one operable safety injection pump.
one operable residual heat removal heat exchanger. and one operable residual heat removal pump.
TS 3.5.2 Action Statement (a) requires that with one ECCS subsystem l ino]erable that the inoperable subsystem be restored to o]erable status i i witlin 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in Hot Standby within the next six lours and in l Hot Shutdown within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
Contrary to the above, from at least September 30, 1991. through October 23, 1996, when Unit 1 was operated in modes 1, 2. and 3. the licensee failed to maintain two independent ECCS subsystems operable, and the provisions of TS 3.5.2 Action Statement (a) were not met.
Specifically, the Unit 1. Train B safety injection pump (1B SIP) was inoperable due to blocked cooling flow to one of its motor coolers and approximately one-third flow to its other motor cooler. (01013)
B. TS 6.7.1.a requires that written procedures be established covering activities delineated in Appendix A of Regulatory Guide 1.33.
Revision 2. dated February 1978.
Regulatory Guide 1.33. Revision 2. dated February 1978, requires that procedures be written for performance of maintenance that can affect safety-related equipment.
Maintenance Procedure Checklist SCL022238. Nuclear Service Cooling Water Heat Exchangers - Periodic Inspections. Revision 8. dated September 29, 1995, provided general instructions to remove, replace, and re-install heat exchanger gaskets and plenums.
Centrary to the above, as of October 25, 1996, the licensee failed to establish adequate procedural guidance to assure the correct installation of motor cooler gaskets and ]lenums for safety-related equipment. As a result, the gasket for tie 18 SIP inboard motor cooler was installed backwards and the plenum on the outboard motor cooler was reversed rendering the pump inoperable. Additionally, the plenums were Enclosure 1 9701140258 961231 PDR ADOcK 05000424 ;
G PDR
Notice of Violation 2 installed backwards on a Unit 2 Train A containment spray pump motor cooler, on a Unit 1 auxiliary component cooling water (ACCW) Pump 2 motor cooler, and on both Unit 2 ACCW Pump 1 motor coolers. (01023)
This is a Severity Level III problem (Supplement I).
Pursuant to the provisions of 10 CFR 2.201, the Georgia Power Com)any is hereby required to submit a written statement or explanation to t1e U.S.
Nuclear Regulatory Commission. ATTN: Document Control Desk. Washington, D.C.
20555 with a copy to the Regional Administrator Region II, and a copy to the NRC Resident Ins)ector at the Vogtle Electric Generating Plant, within 30 days of the date of tie letter transmitting this Notice of Violation (Notice).
This reply should be clearly marked as a " Reply to a Notice of Violation" and should include for each violation: (1) the reason for the violation, or, if contested, the basis for disputing the violation. (2) the corrective steps that have been taken and the results achieved. (3) the corrective steps that will be taken to avoid further violations, and (4) the date when full compliance will be achieved. Your response may reference or include previously docketed correspondence, if the correspondence adequately addresses.
the required response. If an adequate reply is not received within the time i specified in this Notice, an order or a Demand for Information may be issued as to why the license should not be modified, suspended, or revoked, or why such other action as may be proper should not be taken. Where good cause is shown. consideration will be given to extending the response time.
Under the authority of Section 182 of the Act. 42 U.S.C. 2232, this response shall be submitted under oath or affirmation.
Because your res)onse will be placed in the NRC Public Document Room (PDR), to the extent possi]le. it should not include any personal privacy 3roprietary, or safeguards information so that it can be placed in the PDR wit 1out I redaction. However, if you find it necessary to include such information, you should clearly indicate the specific information that you desire not to be l placed in the PDR. and provide the legal basis to support your request for
! withholding the information from the public.
Dated at Atlanta, Georgia this31st day of December 1996 i
1
1 LIST OF PREDECISIONAL ENFORCEMENT CONFERENCE ATTENDEES DECEMBER 19. 1996 Georoia Power Comoany J. Woodard. Senior Vice President. Georgia Power Company C. McCoy Vice President. Vogtle Electric Generating Plant (VEGP)
J. Beasley, General Manager. VEGP ,
K. Holmes. Maintenance Manager. VEGP j L. Ward. Manager. Engineering and Licensing. Southern Nuclear Operating l Company l
J. Bailey. Manager. Licensing. VEGP 1 G. Hooper. Engineering Supervisor VEGP l W. Lewis. Plant Equipment Operator. VEGP 1 S. Saylors. Mechanic. VEGP i D. Lloyd. Project Engineering Manager. Southern Company Services )
i Nuclear Reculatory Commission !
L. Reyes. Deputy Regional Administrator. Region II (RII) )
E. Merschoff. Director. Division of Reactor Projects (DRP). RII I B. Uryc. Director. Enforcement and Investigations Coordination Staff (EICS) RII l P. Skinner. Chief. Projects Branch 2. DRP. RII D. Wheeler. Project Manager. Office of Nuclear Reactor Regulation
- C. Ogle. Senior Resident Inspector. VEGP. RII*
M. Widmann, Resident Inspector. VEGP RII R. Bernhard, Senior Reactor Analyst, RII A. Boland. Enforcement Specialist. EICS. RII R. Carrion. Project Engineer. DRP. RII R. Hannah. Public Affairs Officer. RII Public Two members of the public attended the conference.
i
- Participated by Telephone Enclosure 2
,4
s PREDECISIONAL ENFORCEMENT CONFERENCE AGENDA VOGTLE DECEMBER 19,1996, AT 10:00 A.M.
NRC REGION 11 OFFICE, ATLANTA, GEORGIA
- 1. OPENING REMARKS AND INTRODUCTIONS
- S. Ebneter, Regional Administrator
- 11. NRC ENFORCEMENT POLICY B. Uryc, Director Enforcement and investiga+ ion Coordination Staff ill.
SUMMARY
OF THE ISSUES S. Ehneter, Regional Administrator IV. STATEMENT OF CONCERNS / APPARENT VIOLATION E. Merschoff, Director Division of Reactor Projects V. LICENSEE PRESENTATIOiV VI. OREAK / NRC CAUCUS Vll. NRC FOLLOWUP QUESTIONS Vill. CLOSING REMARKS S. Ebneter, Regional Administrator f
/
i l
s Enclosure 3 i
4 APPARENT VIOLATION Technical Specifications 6.7.1.a requires that written procedures be established covering activities delineated in Appendix A of Regulatory Guide 1.33, Revision 2, February 1978.
, Regulatory Guide 1.33, Rev. 2, February 1978, requires that procedures be I
written for performance of maintenance that can affect safety related equipment.
Maintenance Procedure Checklist SCLO22238, NSCW Heat Exchangers -
Periodic Inspections, provides general instructions to remove, replace, and re-install heat exchanger gaskets and plenums.
Since initial operation until October 25,1996, the licensee failed to properly establish adequate procedural guidance to correctly install the motor cooler gaskets and plenums. This failure to properly establish procedural guidance was identified on October 15,1996, when the Unit 1 safety injection pump (SIP) train B was discovered to have inadequate cooling water flow. As a result, the evaluation by the licensee identified that this specific condition of i
SIP had existed at least since September 30,1991 and caused the pump to l j be in a condition which would have resulted in the inability of the pump to perform its intended safety function for the design basis accident (i.e., .
I, medium break LOCA). Also, SIP 18 and the Unit 2 containment spray pump l (CSP) train A motor coolers were identified as each having one plenum installed backwards.
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1 1
1 NOTE: THE APPARENT VIOLATION DISCUSSED IN THIS i PREDECISIONAL ENFORCEMENT CONFERENCE IS SUBJECT i TO FURTHER REVIEW AND IS SUBJECT TO CHANGE PRIOR TO ANY REF"LTING ENFORCEMENT DECISION.
PREDECISIONAL ENFORCEMENT CONFERENCE !u DEGRADED SAFETY INJECTION PUMP MOTOR COOLER ISSUE ]g j DECEMBER 19,1996 4
!
- OPENING REMARKS GPC/NRC i
KEN MCCOY DESCRIPTION OF PROBLEM BARNIE BEASLEY 4
- CIIRONOLOGY BARNIE BEASLEY
- CAUSES KEN IlOLMES
- CORRECTIVE ACTIONS KEN IIOLMES
- 1. IMMEDIATE
- 2. LONG TERM
- 3. FUNCTIONAL TEST I
SAFETY SIGNIFICANCE LEWIS WARD 4
- CLOSING REMARKS GPC/NRC KEN McCOY t
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PROBLEM DESCRIPTION i
i
- The Safety Injection Pump 1B was inoperable in excess j of Technical Specifications allowed out-of-service time j from 1991 until 10/22/96, due to incorrectly assembled motor coolers.
i e The inoperability of the Safety Injection Pump 1B in conjunction with the out-of-service time due to normal maintenance / testing for the Safety Injection Pump 1A resulted in an unanalyzed condition for Unit 1.
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! SAFETY INJECTION SYSTEM s
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l The purpose of this system is,in the event of an accident, to deliver borated water to the Reactor
- Coolant System. Pump suction is front the Refueling l Water Storage Tank during the injection phase, and i from the Containment Emergency Sumps via Residual
- Heat Removal during the recirculation phase.
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i PROBLEM DESCRIPTION Additional Details i
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- Incorrect reassembly of the motor coolers.
j 1. Gaskets were reversed on one Safety Injection
- Pump 1B motor cooler totally blocking flow.
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- 2. A plenum installed incorrectly on the other Safety Injection Pump 1B motor cooler which resulted in bypassing two-thirds of the cooler.
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! CHRONOLOGY J
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- During routine rounds, an operator noticed one motor cooler return line noticeably warmer.
The Unit Shift Supervisor who was immediately notified requested an engineering evaluation.
l (10/15/96)
- A contact pyrometer indicated 14 degrees F higher on one motor cooler return line. Suspected one motor cooler had no flow.
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(10/15/96)
- A work order was initiated to measure flow. One cooler had essentially zero flow and the other motor cooler had a flow rate of 34 gpm.
(10/15/96)
- An engineering evaluation determined that the motor cooler could perform its safety function based on flow of 34 gpm through one motor cooler.
(10/15/96)
- Disassembly found gasket blanking offinlet of one motor cooler.
(10/22/96)
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- During disassembly / reassembly of Safety Injection Pump IB motor cooler personnel noted possibility of reversing plenum.
(10/22/96)
- Temperature readings indicated possibly reversed plenums for the other Safety Injection Pump IB motor cooler and one of the Containment Spray Pump 2A motor coolers.
(10/24/96)
- Coincidental with an investigation oflow flow readings for Containment Spray Pump 2A motor cooler, boroscope inspections confirmed contact pyrometer technique. This inspection indicated one reversed pienum for Containment Spray Pump 2A. Plenum was corrected.
(10/24/96)
Z)scassem/f/
e ' T yo r - liispectionsindicated one reversed plenum for Safety Injection Pump IB. Plenum was corrected.
(10/25/96)
- After further engineering evaluation, a one hour notification was made on 11/6/96 to the NRC Operations Center for the unanalyzed condition.
- A review of work orders determ'ined Safety Injection Pump IB motor cooler assemblies' configuration in error since 1991 and possibly since initial installation.
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CAUSES OF EVENT
- Tlic gaskets of one motor cooler and the plenum of the other motor cooler were improperly installed.
i
. The gasket installation error was due to poor maintenance practice and an inadequate procedure.
- The vendor manual contained no specific instructions on plenum disassembly / reassembly; leading to:
o Lack of knowledge and training o Proced ural inadeq uacy (general instructions) 1
- No specific testing was performed for heat exchangers. Functional test consisted of pump inservice test and verification of no leakage.
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! COlutECTIVE ACTIONS
- IMMEDIATE
- The gaskets and plenum were properly installed on Safety Injection Pump 1B.
- Gaskets installed on 10/22/96 and plenum installed on 10/25/96.
!
- ECCS motor coolers inspected for reversed plenums.
I -Utilizing temperature measurement methodology on 10/24-25/96.
) -Second verification using alternate test method on 11/19-23/96.
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- Plenums marked on motor coolers to indicate proper orientation. .
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LONG TERM .u .
. Procedure 27118-C," Westinghouse Large Frame Motor Heat Exchanger Maintenance" has been developed providing instructions for correct disassembly / reassembly.
. The existing maintenance checklist has been revised to reference the new procedural requirements.
- Inspected the Auxiliary Component Cooling Water motor coolers (similar large frame Westinghouse motors) and found similar problems with reversed plenums. Plenums were corrected.
- Evaluating other heat exchangers/ coolers for similar problems.
. Training will be provided for maintenance personnel describing this event and to provide instructions on the new procedure.
- Issue As Built Notices to vendor manuals that include drawings and instructions for motor cooler disassembly / reassembly.
- A Nuclear Network entry has been made to alert the industry of potential problems.
- tr em 4
VERIFICATION / FUNCTIONAL TEST
- Use concurrent dual verification for gasket and plenum installation.
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Reviewing functional test requirements for heat exchangers to ensure adequate functional tests are performed.
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SAFETY SIGNIFICANCE 4
3 System Operatine Requirements o
, The SI pumps function as part of the Emergency Core Cooling System (ECCS) 1
- The ECCS is comprised of the CVCS centrifugal charging pumps (high head), SI pumps khead), and RHR l pumps (low head) T ,,f g n
- They auto start on an SI signal (pressurizer pressure low, steam line pressure low, and containment pressure -
high 1)
- - They are assumed to be available for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following a LOCA.
o The SI pumps are not required for normal plant operation.
TechnicalSpecification Requirements 3.5.2 Two trains of ECCS subsystems (including SI pumps) shall be operable-72 hour action required. Modes 1,2 and 3 3.5.3.2 Both SI pumps shall be inoperable-Modes 4,5 and 6.
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SI Pump 1B Actual Conditions o Motor cooler flow was normally greater than design flow of 30 gpm (15 gpm per cooler), except in 2 instances since 1991, when flow as low as 11.4 gpm was measured due to debris (see Table 1) o Lowest flow of 11.4 gpm was used in worst case analysis of cooling capability.
o Worst case motor winding temperature was calculated to reach 198 C (rated @ 130 C, qualified @ 210 C for 168 hrs). Therefore, the winding should not have failed during a post-accident period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
o Assuming the bearing and lube oil were at the same temperature as the winding (198 C), bearing failure could have occurred in 1-2 hours.
Simultaneous Inoperability of Redundant Sub-Train (SI Pump IA)
The attachment (Table 2) shows the history of Out-of-Service times for redundant SI Pump 1 A since October 1991.
This is summarized as follows:
o 24 times for quarterly SSPS slave relay testing-average of about 22 minutes per test. The pump is actually started during this test, but would not receive an automatic SI signal to start. It could quickly be returned to service if needed.
o 2 times-NSCW train A was tagged for design modification (40 minutes) and tower inspection (55 minutes). NSCW and SI Pump 1 A could have been quicidy returneo' ta service if needed.
o 1 time-NSCW Train A and Train B were inoperable (TS 3.0.3) for 17 minutes due to pipe cracking, however, Train A was in service the entire time.
o I time-SI pump 1 A was OOS for 118 minutes to clean and flush its flow orifice. It could have been quickly returned to service if needed.
o The average annual out-of-service time based on this data is about 21/2 hours. The PSA evaluation conservatively used 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />.
- ..........,,, .,1 s es,, c.,c, amu we ammi-m eum wun i runstens o Assumptions:
-Since SI pumps are needed primarily for small break LOCA:
-SI pump IB operates for 1st hour of transient, then fails due to lack of cooling water
-SI pump 1 A inoperable (single failure, etc.)
-Used WCAP-10054-P, Addendum 2, Revision 1 methodology, which has been approved by NRC (August 1996) but not analysis of record for Vogtle o Results:
-Results, based on screening of several sizes of small-break LOCAs
-PCT does not exceed 2200 F
-Therefore, would have met its safety function.
Probabilistic Safety Assessment o Assumptions:
-SI 1B pump not available for entire year
-SI 1 A pump inoperable for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per year o Results
-Average Annual Core Damage Frequency (CDF) increase is 2.4E4, a 5.3% change. (This increase is within the EPRI"PRA Applications Guidelines" criteria for an acceptable permanent risk increases)
-Average Annual Large Early Release Frequency (LERF) increase is 8.0E#, a 48% change.
-As a percentage of the CDF, the contnoution of LERF would only increase from 3 7% to 5 2% of the CDF . .
which amounts to a negligible impact on the overall containment performance capability.
e
Summary o SI pump 1B would have performed its safety function for one to several hours following a LOCA, which would have met its required safety function .
o SI pump 1 A would historically have been available prior to failure of SI pump 1B.
e l
1 Unit le Train "B" Safety Injection Pump Equipment Tag Number 1-1204-P6-004 j Degraded Motor Cooling Water Flow Evaluation '
(Page 6 of 6) .
TABLE 1 (NSCW Cooler Flow Trends and Surveillance Information) l I
Measured Flow Test Date (epm) Comments I
10/24/91 35.4 Accectable .'
08/01/94 36.2 Acceptable 08/28/95 11.7 I Acx:ectable per letter loa SG-14475'"*""
10/02/95 36.8 ' Accentable 11/03/95 11.4 1 A= Ale per letter log SG 14578'"*""
11/30/95 37.0 l Accentable 12/12/95 1 38.2 l Accectable 12/29/95 1 41.6 l Accectable 01/24/96 40.0 l Arr emable 02/20/ % 36.8 Acceptable 03/23/ % 35.7 Aremtable 04/14/96 37.3 Aremtable 05/14/96 38.9 IA . table 06/11/96 35.2 Acceptable 07/10/96 39.2 Accemable 08/06/96 35.2 Acceptable 09/03/96 34.2 Acceptable 09/29/96 38.6 i Acceotable 10/24/96 3 9. I'" ** l Accentable per lener 102 SG 15314 '* ** " l 11/01/96 N/A l Review provided by letter 102 SG-15314 '* ** *'
I Table 1 Notes: s
- 1) When tius analjsis was performed. it w2s not known that the motor coolers had been installed incorrectly.
- 2) Although the measured flow rate is acceptable, it was discovered that one of the coolers had the plenum gasket incorrectly installed. This resulted in cooling water flow through only one of the two motor coolers.
- 3) Acceptability for this condition was based on total cooling water flow through one of the coolers. This review was based on engmeenng judgmmt by consideration of the margin identified in previous evaluations. A later prelimmary analysis indicated that the motor temperatures never exceeded the 130*C limitation (the results indicated that the maximum motor temperature would be approximately 127'C).
- 4) SCS-Engineering was notified that one of the plenums on the Unit 1 Train"B" Si pump motor coolers had been installed incorrectly. This resulted in only one pass of w2ter through this cooler. This condition e:usted while the other cooler had an inccrrectly installed plenum to cooler gasket which totally blocked cooling water flow to this cooler. Based on a prelimmary review. Design Engineering could not conclude that the Unit 1, Train "B" Si pump could have perform.:d its safety-related function.
TABLE 2 SI PUMP 1A INOPERABLE OR OUT-OF-SERVICE !
4 DATE OOS COMMENTS TIME l
11/12/91 20* 14618-1 SLAVE RELAY TEST
! 12/24/91 20* 14618-1 SLAVE RELAY TEST
- 03/17/92 20* 14618-1 SLAVE RELAY TEST 06/12/92 20* 14618-1 SLAVE RELAY TEST 09/01/92 20* 14618-1 SLAVE RELAY TEST l j 11/24/92 20* 14618-1 SLAVE RELAY TEST I 02/16/93 20* 14618-1 SLAVE RELAY TEST 05/11/93 20* 14618-1 SLAVE RELAY TEST 08/03/93 20* 14618-1 SLAVE RELAY TEST j 10/26/93 20* 14618-1 SLAVE RELAY TEST i
01/18/94 22 14618-1 SLAVE RELAY TEST 04/12/94 30 14618-1 SLAVE RELAY TEST 07/05/94 29 14618-1 SLAVE RELAY TEST 09/03/94 41 14618-1 SLAVE RELAY TEST 10/26/94 25 14618-1 SLAVE RELAY TEST _
12/20/94 44 14618-1 SLAVE RELAY TEST 03/15/95 20* 14618-1 SLAVE RELAY TEST 06/06/95 20* 14618-1 SLAVE RELAY TEST 08/09/95 40, A TRN NSCW OOS FOR DESIGN MOD 08/29/95 20* 14618-1 SLAVE RELAY TEST 09/03/95 118 1 A SIP IN PTL FOR FO FLUSH 11/21/95 20* 14618-1 SLAVE RELAY TEST 12/15/95 55 TRN A NSCW IN PTL FOR TOWER INSPECTION 02/13/96 20* 14618-1 SLAVE RELAY TEST 02/20/96 17 T.S. 3.0.3. ON NSCW
)
05/09/96 20* 14618-1 SLAVE RELAY TEST 08/22/96 20* 14618-1 SLAVE RELAY TEST j 10/22/96 20* 14618-1 SLAVE RELAY TEST l
l ESTIMATED
- -vo.n v .u.nuuuw i
a o Problem was licensee-identified by an alert operator i
o Vendor information was inadequate to identify the plenum issue o Prompt corrective action was taken to restore the deficient conditions o
, A comprehensive inspection of other coolers and root cause determination was completed i
o Lasting corrective actions are being implemented with procedure changes and training i o The industry has been notified of this issue o The event isjudged to be non-risk significant i
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