ML18135A150
| ML18135A150 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 09/12/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Proffitt W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 7909270166 | |
| Download: ML18135A150 (9) | |
Text
I In Reply Refer To:
RII:JPO 50-339 50-405 50-281 UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 SEP 1 2 1979 Virginia Electric and Power Company Attn:
W. L. Proffitt Senior Vice President, Power P. O. Box 26666 Richmond, Virginia 23261 Gentlemen:
'\\
e Enclosed is IE Bulletin 79-23 which requires action by you with regard to your power reactor facility(ies) with an operating license or a construction permit.
Should you have questions regarding this Bulletin or the actions required of you, please contact this office.
Enclosures:
- 1.
- 2.
List of IE Bulletins Issued in the Last Six Months Sincerely, r-::~=y- ~-
~
~------:::,
~
James P. O'Reilly Regional Director 7 9 O 92 'i O((a(o
Virginia Electric and Power Company cc w/encl:
W.R. Cartwright, Station Manager Post Office Box 402 Mineral, Virginia 23117 P. G. Perry Senior Resident Engineer Post Office Box 38 Mineral, Virginia 23117 W. L. Stewart, Manager Post Office Box 315 Surry, Virginia 23883 SEP 1 2 1979 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 September 12, 1979 Accession No. 7908220104 SSINS No. :
6820 IE Bulletin No. 79-23 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 Band C 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:
"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 ~onnection
IE Bulletin No. 79-23 September 12, 1979 Page 2 of 3 between the neutrals, or a connection through common grounding of both neutrals, are equally undesirable conditions.
Whenever either of these undesirable con-ditions exist, high circulating currents can be induced by harmonics.
These currents may exceed transformer ratings and result in transformer 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 limitations 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.
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 Op~ra-tfOijS lnsp~~ffoµ, Washingtq~, D.C 2Qij~?*
- 1**
.I
- j)*.','
I
IE Bulletin No. 79-23 September 12, 1979 Page 3 of 3 Approved by GAO, B180225 (R0072); clearance expires 7/31/80.
Approval was given under a blanket clearance specifically for identified generic problems.
IE Bulletin No. 79-23 September 12, 1979 Bulletin No.
79-23 79-22 79-21 79-20 79-19 79-18 79-17 79-16 79-15 (Supp. 1) 79-15 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Subject Date Issued Potential Failure of Erner-9/12/79 gency Diesel Generator Field Exciter Transformer Possible Leakage of 9/5/79 Tubes of Tritium Gas Used in Timepieces for Luminosity Temperature Effects 8/13/79 on Level Measurements Packaging Low-Level 8/10/79 Radioactive Waste for Transport and Burial Packaging Low-Level 8/10/79 Radioactive Waste for Transport and Burial Audibility Problems Encountered on Evacua-tion of Personnel from High-Noise Areas Pipe Cracks in Stagnant Borated Water ~ystems at PWR Plants Vital Area Access Controls Deep Draft Pump Deficiencies Deep Draft Pump Deficiencies 8/7 /79 7/26/79 7/26/79 7/18/79 7 /11/79 Enclosure Page 1 of 4 Issued To All Power Reactor Facilities with an OL or a CP Each Licensee who Receives Tubes of Tritium Gas in Timepieces for Luminosity All PWRs with an operating license All Materials Licensees who did not receive Bulletin No. 79-19 All Power and Research Reactors with OLs, fuel 'facilities except uranium mills, and certain materials licensees All OL's for action All CP's for information All PWR' s with operating license All Holders of and applicants for Power Reactor Operating Licenses who anticipate loading fuel prior to 1981 All Power Reactor Licensees with a CP and/or OL All Power Reactor Licensees with a CP and/or OL
e IE Bulletin No. 79-23 September 12, 1979 Bulletin No.
79-14 (Correc-tion) 79-14 (Supp. 2) 79-14 (Rev. 1) 79-14 79-13 (Rev. 1) 79-13 79-12 79-11 79-10 79-09 79-08 79-07 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Subject Seismic Analyses for As-Built Safety-Related Piping System Seismic Analyses for As-Built Safety-Related Piping System 7
Seismic Analyses for As-Built Safety-Related Piping System Seismic Analyses for As-Built Safety-Related Piping System Cracking in Feedwater System Piping Cracking in Feedwater System Piping Date Issued 7/27/79 9/7 /79 7 /18/79 7 /2/79 8/30/79 6/25/79 Short Period Scrams at 5/31/79 BWR Facilities Faulty Overcurrent Trip 5/22/79 Device in Circuit Breakers for Engineered Safety Systems Requalification Training.
5/11/79 Program Statistics Failures of GE Type AK-2 4/17/79 Circuit Breaker in Safety Related Systems Events Relevant to BWR 4/14/79 Reactors Identified During
- Three Mile Island Incident Seismic Stress Analysis of Safety-Related Piping 4/14/79
,I Enclosure Page 2 of 4 Issued To All Power Reactor Facilities with an OL or a CP All Power Reactor facilities with an OL or a CP All Power Reactor Facilities with an OL or a CP All Power Reactor facilities with an OL or a CP All PWR's with an operating license All PWRs with an OL for action. All BWRs with a CP for information All GE BWR Facilities with an OL All Power Reactor Facilities with an OL or a CP All Power Reactor Facilities with an 01 All Power Reactor Facilities with an OL or CP All BWR Power Reactor Facilities with an OL All Power Reactor Facilities with an Of 9+ Cf
e IE Bulletin No. 79-23 September 12, 1979 Bulletin
- No..79-06C 79-06B 79-06A (Rev. 1)79-06A 79-06 79-05C 79-05B 79-05A 79-05 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Subject Nuclear Incident at Three Mile Island - Supplement Review of Operational Errors and System Mis-alignments Identified During the Three Mile Island Incident Review of Operational Errors and System Mis-alignments Identified During the Three Mile Island Incident Review of Operational Errors and.System Mis-alignments Identified During the Three Mile Island Incident Review of Operational Errors and System Mis-alignments Identified During the Three Mile Island Incident Nuclear Incident at Three Mile Island - Supplement Nuclear Incident at Three Mile Island Nuclear Incident at Three Mile Island Nuclear Incident at Three Mile Island Date Issued 7/26/79 4/14/79 4/18/79 4/14/79 4/11/79 7/26/79 4/21/79 4/5/79 4/1/79
/
- Enclosure Page 3 of 4 Issued To To all PWR Power Reactor Facilities with an 01 All Combustion Engineer-ing Designed Pressurized Water Power Reactor Facilities with an Operating License All Pressurized Water Power Reactor Facilities of Westinghouse Design with an 01, All Pressurized Water Power Reactor Facilities of Westinghouse Design with an 01 All Pressurized Water Power Reactors with an 01 except B&W facilities To all PWR Power Reactor Facilities with an 01 All B&W Power Reactor Facilities with an 01 All B&W Power Reactor Facilities with an 01 All Power Reactor Facilities with an 01 and CP
IE Bulletin No. 79-23 September 12, 1979 Bulletin No.
79-02 (Rev. 1)
(Supp. 1) 79-02 (Rev. 1) 79-0lA LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Subject Date Issued Pipe Support Base Plate 8/20/79 Designs Using Concrete Expansion Anchor Bolts Pipe Support Base Plate 6/21/79 Designs Using Concrete Expansion Anchor Bolts Environmental Qualification 6/6/79 of Class lE Equipment (Deficiencies in the Envi-ronmental Qualification of ASCO Solenoid Valves)
Enclosure Page 4 of 4 Issued To All Power Reactor Facilities with an OL or a CP All Power Reactor Facilities with an OL or a CP All Power Reactor Facilities with an OL or CP