ML19254B298
| ML19254B298 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/12/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Herbein J METROPOLITAN EDISON CO. |
| References | |
| NUDOCS 7909270064 | |
| Download: ML19254B298 (1) | |
Text
UNITED STATES Yb y
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NUCLEAR REGULATORY COMMISSION y y3#
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Docket Nos. 50-289 50-320 Metropolitan Edison Company ATTN:
Mr. J. G. Herbein Vice President P. O. Box 542 Reading, Pennsylvania 19603 Gentlemen:
The enclosed IE Bulletin 79-23 is forwarded to you for inf!.mation.
No written response is required at thic time. If you desire additional information regarding tFis matter, please contact this office.
Sincerely, m
Boyce H. Grier
' Director
Enclosures:
1.
List of IE Bulletins Issued in the Last Six Months cc w/encls:
E. G. Wallace, Licensing Manager J. J. Barton, Project Manager R. C. Arnold, Vice President - Generation L. L. Lawyer, Manager - Generation Operations G. P. Miller, Manager - Generating Station - Nuclear J. L. Seelinger, Unit 1 Superintendent W. E. Potts, Unit 1 Superintendent - Technical Support J. B. Logan, Unit 2 Superintendent G. A. Kunder, Unit 2 Superintendent - Technical Support I. R. Finfrock, Jr.
Mr. R. Conrad G. F. Trowbridge, Esquire J. Lieberman, Esquire Miss Mary V. Southard, Chairman, Citizens for a Safe Environment N
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104524$
ENCLOSURE 1 Accession No. 7908220104 SSINS No.:
6820 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 79-23 Date:
September 12, 1979 Page 1 of 3 POTENTIAL FAILURE OF EMERGENCY DIESEL GENERATOR FIELD EXCITER TRANSFORMER Description of Circumstances:
Florida Power and Light Company recently reported a problem encountered during a 24-hour full load test of the emergency diesel generators (EDG) at their Turkey Point facility.
Approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> into the test, the A-EDG tripped due to a differential-relay lockout on B and L phases; the B-EDG was manually stopped, thus interrupting the test at that point in time.
Subsequent investigation and testing by the licensee revealed a design error on both the A and B EDGs which resulted in overheating of the Exciter Power Transformers (EPTs) at sustained high load operation.
The following nameplate data applies to the equipment installed at Turkey Point:
Emergency Diesel Generator General Motors (Electro-Motive Division)
Model EMD-999-20 Engine-turbocharged, 2 cycle, EMD design 20-645E4 Generator-EMD-design Model A-20 Exciter Power Transformer GE-single phase Model-9T24Y1004 Serial-MD Cycles-60 KVA 15 Insulation-4160 V The manufacturer's findings and recommendations regarding the above problem are described below:
10452Q
IE Bulletin No. 7'-23 Date:
September 12, 1979 Page 2 of 3 "A potential problem can exist if the neutral of the generator and the neutral of the primary windings of the excitation power transformer (EPT) (sometimes referred to as the control power transformer (CPT)) are connected.
A direct connection between the neutrals, or a connection through common grounding of both neutrals, are equally undesirable conditions.
Whenever either of these undesirable conditions exist, high circulating currents can be induced by harmonics.
These currents may exceed transformer ratings and result in trans-former damage or failure.
The connection between the neutrals, either direct or through common grounding, may have been designated in the original wiring design, or may have been subsequently added by a contractor or by power plant personnel to balance excitation transformer voltages relative to the generator.
No significant benefit is obtained by balancing the primary voltage of the excitation trans-former by means of these connections."
According to the manufacturer, "to avoid this potential transformer damage or failure, the circuitry of each installation should be examined to determine if a circuit exists between the neutral of the primary windings of the EPT or CPT and the generator neutral.
If the condition exists, the neutral circuit should be disconnected, and the transformer primary neutral allowed to float."
Licensees may utilize Regulatory Guide 1.108, Revision 1, as a reference for the periodic testing of diesel generator units used as on-site electric power systems at nuclear power plants.
Action to be Taken by Licensees:
For all power reactor facilities with an operating license or a construction permit:
1.
Determine whether or not connections have been made between low KVA rated transformers and high KVA rated EDGs without adequate lim #tations on the flow of circulating currents.
If applicable, provide a description of the corrective action being taken to address this problem.
2.
Provide a schedule for the completion of a sustained full-load operation test of the EDGs for a duration of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or provide the results of the similar long duration, full-load test which has already been completed on the EDGs installed at your facility.
The test should demonstrate full-load carrying capability for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of which 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> should be at a load equivalent to the continuous rating of the diesel generator and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a load equivalent to the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rating of the diesel generator.
The test should also verify that voltage and frequency requirements are maintained and that the cooling system functions within design limits.
3.
Provide a written report of the above actions within 45 days of the receipt of this Bulletin.
10452SD
IE Bulletin No. 79-23 Date:
September 12, 1979 Page 3 of 3 Reports should be submitted to the Director of the appropriate NRC Regional Office.
A copy of your report should be sent to the U. S. Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Opera-tions Inspection, Washington, D.C 20555.
Approved by GAO, B180225 (R0072); clearance expires 7/31/80.
Approval was given under a blanket clearance specifically for identified generic problems.
1045 251
IE Bulletin No. 79-23 Date:
September 12, 1979 Page 1 of 5 ENCLOSURE 2 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Bulletin Subject Date Issued Issued To No.78-12B Atypical Weld Material 3/19/79 All Power Reactor in Reactor Pressure Facilities with an Vessel Welds OL or CP 79-01A Environmental Qualification 6/6/79 All Power Reactor of Class 1E Equipment Facilities with an (Deficiencies in the Envi-OL or CP ronmental Qualification of ASCO Solenoid Valves) 79-02 Pipe Support Base Plate 6/21/79 All Power Reactor (Rev 1)
Design Using Concrete Facilities with an OL Expansion Anchor Bolts or CP 79-02 Same Title as 79-02 8/20/79 Same as 79-02 (Rev 1)
(Rev 1)
(Rev 1)
(Supplement No. 1) 79-03 Longitudinal Weld Defects 3/12/79 All Power Reactor in ASME SA-312 Type Facilities with 304 Stainless Steel Pipe an OL or CP Spools Manufactured by Youngstown Welding and Engineering Company 79-04 Incorrect Weights for 3/3r All Power Reactor Swing Check Valves Facilities with an Manufactured by Velan OL or CP Engineering Corporation 79-05 Nuclear Incident at 4/1/79 All Babcock and Three Mile Island Wilcox Power Reactor Facilities with an OL, Except Three Mile Island 1 and 2 (For Action),
and All Other Power Reactor Facilities With an OL or CP (For Information) 1045 252
IE Bulletin No. 79-23 Date:
September 12, 1979 Page 2 of 5 LIST OF IE BULLETINS ISSUED IN LAST SIX MONTHS (CONTINUED)
Bulletin Subject Date Issued Issued To No.79-05A Nuclear Incident at 4/5/79 Same as 79-05 Three Mile Island -
Supplement 79-05B Nuclear Incident at 5/21/79 Same as 79-05 Three Mile Island -
Supplement 79-06 Review of Operational 4/11/79 Ali Pressurized Water Errors and System Mis-Power Reactor Facil-alignments Identified ities with an OL Except During the Three Mile B&W Facilities (For Incide.t Action), All Other Power Reactor Facil-ities with an OL or CP (For Information)79-06A Same Title as 79-06 4/14/79 All Westinghouse Designed Pressurized Power Reactor Facil-ities with an OL (For Action), and All Other Power Reactor Facilities with an OL or CP (For Information)79-06A Same Title as 79-06 4/18/79 All Westinghouse (Revision 1)
Desig.ned Pressurized Power Reactor Facil-ities with an CL (For Action), and All Other Power Reactor Facilities with an OL or CP (For Information) 1045 253
IE Bulletin No. 79-23 Date:
September 12, 1979 Page 3 of 5 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS (CONTINUED)
Bulletin Subject Date Issued Issued To No.79-06B Same Title as 79-06 4/14/79 All Combustion Engineering Designed Pressurized Power Reactor Facilities with an OL (For Action), and All Other Power Reactor Facilities with an OL or CP (For Information) 79-05C&O6C Nuclear Incident at 7/26/79 All PWR Power Three Mile Island -
Reactor Facilities Supplement with an OL.
79-07 Seismic Stress Analysis 4/14/79 All Power Reactor of Safety-Related Piping Facilities with &n OL or CP 79-08 Events Relevant to 4/14/79 All BWR Power Boiling Water Power Reactor Facilities Reactors Identified with an OL (For During Three Mile Action), All Other Island Incident Power Reactor Facil-ities with an OL or CP (For Information) 79-09 Failures of GE Type 4/17/79 All Power Reactor AK-2 Type Circuit Facilities with an Breaker in Safety OL or CP Related Systems 79-10 Requalification Training 5/11/79 All Power Reactor Program Statistics Facilities with an OL 4
IE Bulletin No. 79-23 Date:
September 12, 1979 Page 4 of 5 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS (CONTINUED)
Bulletin Subject Date Issued Issued To No.
79-11 Faulty Overcurrent Trip 5/22/79 All Power Reactor Device in Circuit Breakers Facilities with an for Engineered Safety OL or CP Systems 79-12 Short Period Scrams at 5/31/79 All GE BWR Facilities BWR Facilities with an OL 79-13 Cracking in Feedwater 6/25/79 All PWRs with an System Piping OL (for Action),
All Other Power Reactor Facilities with an OL or CP (For Information) 79-13 Cracking in Feedwater 8/30/79 All Designated Ap-(Revision 1) System Piping plicants for OLS 79-14 Seismic Analysis for 7/2/79 All Power Reactor As-Built Safety Related Facilities with an Piping Systems OL or CP 79-14 Same Title as 79-14 7/18/79 Same as 79-14 (Revision 1) 79-14 Same Title as 79-14 8/15/79 Same as 79-14 (Supplement) 79-14 Same as Title 79-14 9/7/79 Same as 79-14 (Supplement 2) 79-15 Deep Draft Pump Defi-7/11/79 All Power Reactor ciencies Facilities with an OL or CP 79-16 Vital Aret Access Con-7/30/79 All Holders of and trols Applicants for Reactor Operating Licenses 79-17 Pipe Cracks in Stagnant 7/26/79 All PWR Power Reactor Borated Water Systems Facilities with an OL at PWR Plants 1045 2Sji
IE Bulletin No. 79-23 Date:
September 12, 1979 Page 5 of 5 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS (CONTINUED)
Bulletin Subject Date Issued Issued To No.
79-18 Audibility Problems 8/7/79 All Power Reactor Encountered on Evacuation Facilities with an OL 79-19 Packaging Low-Level 8/10/79 All Power and Re-Radioactive Waste for search Reactors with Transport and Burial OL, all Fuel Faci-lities (except Uranium Mills), and certain Materials Licensees 79-20 Same Title as 79-19 8/10/79 Certain Materials Licensees 79-21 Temperature Effects on 8/13/79 All Power Reactor Level Measurements Facilities with an OL or CP 79-22 Possible Leakage of Tubes 9/5/79 Each Licensee who of Tritium Gas Used in Receives Tubes of Timepieces for Luminosity Tritium Gas in Timepieces for Luminosity lots 25y