ML20237D057
| ML20237D057 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 08/17/1998 |
| From: | Ogle C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Barron H DUKE POWER CO. |
| References | |
| NUDOCS 9808250011 | |
| Download: ML20237D057 (10) | |
Text
_ _ ___ _-_________ _ _ __ _ _ _ _ _ _ _ _ _
August 17, 1998 Duke Energy Corporation ATTN: Mr.. H. B. Barron Vice President McGuire Nuclear Station 12700 Hagers Ferry Road Huntersv111e, NC 28078-8985
SUBJECT:
MEETING
SUMMARY
- MCGUIRE NUCLEAR STATION
Dear Mr. Barron:
This refers to the meeting that was conducted at your request in the Region II office on August 11, 1998.
During the meeting, members of your staff provided information on recent diesel generator issues at your McGuire Nuclear Station.
A list of attendees and a copy of your presentation handout are enclosed.
It is our opinion that this meeting was beneficial in that it provided the NRC staff with a better understanding of issues associated with diesel generator operation at your McGuire Nuclear Station.
In accordance with Section 2.790(a) of the NRC's " Rules of Practice."
Part 2, Title 10. Code of Federal Regulations, a copy of-this letter and its enclosures will be placed in the NRC Public Document Room.
Should you have any questions concerning this meeting, please contact us.
Sincerely.
Original signed by:
Charles R. Ogle, Chief Reactor Projects Branch 1 Division of Reactor Projects 1
Docket Nos. 50-369, 50-370 License.Nos. NPF-9, NPF-17
Enclosures:
1.
List of Attendees 2.
Licensee Presentation Handouts
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cc w/encls:
~ Michael T. Cash
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ulatory Compliance RekeEnergyCorporation I
Du 12700 Ha Huntersv$ersFerryRoad lle, NC 28078-8985
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cc w/encls cont'd:
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cc w/encls cont'd:
Distribution w/encls:
L. A. Keller F. Rinaldi. NRR i
Licensing - EC050 E. Lea, RII Duke Energy Corporation C. Ogle, RII P. O. Box 1006 C. Pa ne, RII
- Charlotte, NC 28201-1006 PUBLI NRC Resident Inspector p
Legal Department (PB05E)
Duke Energy Cor) oration 422 South Churc1 Street 1
Charlotte, NC 28242-0001
)
Mr. Robert P. Gruber Executive Director Public Staff - NCUC i
P. O. Box 29520 l
Raleigh, NC 27626-0520 J. Michael McGarry, III. Esq.
- Winston and Strawn 1400 L Street, NW Washington, D. C.
20005
- Mel Fry Acting Director Division of Radiation Protection N. C. Dep& Natural Resources artment of Environmental Health 1
3825 Barrett Drive i
Raleigh, NC 27609-7721 County Manager of Mecklenburg County 720 East Fourth Street 1
Charlotte. NC 28202 J
Peter R.- Harden IV Account Sales Manager Energy ystems Sales Westing ouse Electric Corporation P. O. Box 7288 i-Charlotte NC 28241-7288 Dr. John M. Barry, Director Mecklenburg County Department of Environmental Protection 700 North Tryon Street Charlotte, NC 28203 Karen E. Long Assistant Attorney General l
N. C. De artment of Justice P. O. Bo 629 Raleigh, NC 27602 0FFICE Mil:DNP SIGNATLRE
,f, NAIE ELEA DATE 8/ /2 /98 8/
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YES NO YES NO YES ND YES NO YES NO YES NO YES NO OFFICIAL REEEND EXIPY DOCLBENT NAME: G:VICGNT811.5m
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l-l LIST OF ATTENDEES NUCLEAR REGULATORY COMMISSION i
- L.
Plisco, Director, Division of Reactor Projects (DRP) RII l-B.
Mallett, Director. Division of Reactor Safety (DRS) RII V.- McCree. Deputy Director. DRS. RII 1
C.
Ogle, Chief. Branch 1, DRP, RII
- K.
Landis, Chief. Engineering, DRS, RII
~~
S.
Shaeffer. NRC Senior Resident Inspector, McGuire. Nuclear Station E.
Lea. Project Engineer. DRP, RII Duke Enerav Corocration (DEC) l
- B.
Peele. Engineering Manager, McGuire Nuclear Station (MNS)
M.
Cash, Regulatory Compliance Manager. MNS S. 'Grier. Suppler Verification Manager, Duke Energy Corporation B.
Travis, Mechanical Systems Engineering Manager MNS
. N..
Kunkel. Diesel System Engineer MNS l
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McGuire Nuclear Station
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August 11,1998
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% =c AGFNDA
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.s Introduction
^
Diesel Generator History.
Broken Exhaust Valve Seat Insert Dropped Exhaust Valve Seat Insert
+
Stuck Inlet Valve Broken Inlet ValvdOuter Spring ~
Common Cause Analysis IIcalth of Diesel Generators Questions & Comments 2
/
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1
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l Nordberg Engines Built 1970
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j Installed in 1970-71 (Fossil Station)
- ~ 4000 hours0.0463 days <br />1.111 hours <br />0.00661 weeks <br />0.00152 months <br /> / 500 starts per engme i
McGuire Installation 1977
- No complete rebuild performed Total Service to Date i
- ~ 6000 hours0.0694 days <br />1.667 hours <br />0.00992 weeks <br />0.00228 months <br /> /1500 starts per engine 5
I DIESEL GENERATOR HISTORY RELIABILITY IMPROVEMENTS Root Cause Analysis Improvements (1995)
Independent Assessment (9/96-11/96) )-
- Revise Technical Specifications to s!'ow loading
- Delete starting air 2-start Technical Specification
- Replace battery chargers
~'
- Improve generator PMs 100% Diesel Engine Overhauls '(1997) 1 6
3
988 IIROKEN EXIIAUST V ALVE SEAT INSEltT Root Cause:
- Manufacturing / installation defect in valve seat insert Failure Sequence:
~
- Forging or machining flaw results in stress concentration site
- Crack rapidly grows during operation Initially detectable per engine diagnostics after 15 minutes or 4000 cycles of operation Valve seat insert failure after initial 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> of operation (figure 5) 9 c_.n BROKEN EXHAUST VALVFs SEAT INSERT
._..._._._......._1._,.._
.._1._...
_. _._ w Corrective Actions:
1; -
- Replaced cylinder head assembly.
- Finite element stress analysis
- Engine diagnostic data review:
Identifies pre-failure characteristics
(
Verifies each cylinder does not exhibit pre-failure l
characteristics l
- Close-out with Vendor l
l 10
9 STUCK INLET VALVE
-1 Root Cause:
- Insufficient clearance between valve guide and stem Failure Sequence:
- Heads rebuilt with clearance specification from 1972 Nordberg procedure revision verses the original purchase 1970 revision
- Excess friction plus normal delta pressure force was greater than spring force
- Lack of valve seating prevents adequate cylinder compression
- No combustion when fuel is injected (figure 6) 13 i
I STUCK INLET VALVE
=___u._..._..m
~ _.._ _ u _ _.__ _ a Corrective Actions:
- Comparison of Duke to Vendor information concludes the valve stem clearance is the only dimensional deviation I
- Engine diagnostic data review:
Identified characteristics of stuck inlet valve EDG-1B cylinder 6L identified as sluggish
- Replaced EDG-1B cylinder heads 8R and 6L
- Rebuild all spare heads to larger clearance 14 7
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Root Cause:
- No common single root cause
- Cylinder head rebuilds are common to three problems:
Valve seat insert defect Discrepancy in valve guide / stem clearance specifications Unacceptable spring material
- One problem unrelated to cylinder rebuilds:
Excessive cooldown rate for given conditions
- Head bore configuration potential contributing factor 17
)
COMMON CAUSE ANALYSIS
..--.:=
~ -. _.
Corrective Actions:
- Vendor Oversight:
.y Audit of EDG Vendor Appendix B program with focus on
]
areas in relation to recent failures in June 1998 Augmented oversight placed on procurement activities with.,
EDG Vendor A
Review and evaluate Vendor corrective actions EDG procurement specification revision 1
- Root cause failure analysis 4
- Industry network message distributed
- Continued comprehensive engine diagnostic trend.
analysis 18
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REFERENCE FIGURES FIGURE 2 l
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Linkshaft Bearing Linkshaft Journal Degradation Degradation 21 REFERENCE FIGURES FIGURE 3
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Stating Air Housing Sleeve in Housing Shaft Over Heat Damage 22
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REFFRENCE FIGURES FIGURE 6 4
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REFERENCE FIGURES FIGURE 7
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