ML20247H774
| ML20247H774 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 05/14/1998 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-317-98-80, 50-318-98-80, NUDOCS 9805210255 | |
| Download: ML20247H774 (6) | |
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A Curatos 11. Cnese Baltimore Gas and Electric Company Vice President Calven Cliffs Nuclear Power Plant Nuclear Energy 1650 Calvert Cliffs Parkway Lusby, Maryland 2%57 410 495-4455 May 14,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 NRC Region 1 Inspection Report Nos. 50-317/98-80 and 50-318/98-80 and Notice of Violation f
REFERENCE:
(a)
Letter from Mr. J. T. Wiggins (NRC) to Mr. C. II. Cruse (RGE), dated April 14,1998, NRC Region 1 Inspection Report Nos. 50-317/98-80 t
and 50-318/98-80 and Notice of Violation This letter provides Baltimore Gas and Electric Company's response to Reference (a), which identified two violations. Each of the violations cited has been individually addressed as specified in the Enclosure to Reference (a). Individual responses to each of these violations are provided in Attachments (1) and (2).
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ph 9005210255 980514 PDR ADOCK 05000317 G
Docum:nt Control Desk May 14,1998
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Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
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STATE OF MARYLAND
- TO WIT:
COUNTY OF CALVERT I, Charles 11. Cruse, being duly sworn, state that I am Vice President, Nuclear Energy Division, Baltimore Gas and Electric Company (BGE), and that I am duly authorized to execute and file this response on behalf of BGE. To the best of my knowledge and belief, the statements contained in this document Are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon Mformation provided by other BGE employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.
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Me -
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Subscribed and sworn before me, a Notary Public in and for the State of Maryland and County of (hf1AAi)
.this /@l; day of 7Wu/
.1998.
O WITNESS my liand and Notarial Seal:
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Mld A )
Notary Public i
My Commission Expires:
dMAAu !,N@bd h Date CliC/EMT/ dim 1.
Attachments cc:
R. S. Fleishman, Esquire
- 11. J. Miller, NRC J. E. Silberg, Esquire Resident Inspector,NRC S. S. Bajwa, NRC R. I. McLean, DNR A. W. Dromerick, NRC J.11. Walter, PSC l
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ATTACIIMENT (1)
NRC REGION I INSPECTION REPORT NOS. 50-3I7/98-80 AND 0-318/98-80 VIOLATION 98-80-03 A.
10 CFR Part 50, Appendix B, Criterion XI, " Test Control," requires uritten test procedures which incorporate acceptance limits contained in applicable design documents.
Contrary to the above, a post-modification procedure, ETP 017, Rev. O, DGP [ Diesel Generator Project} 1A Battery Pre-operational Test, dated June 16,1995, failed to incorporate an appropriate acceptance criterionfor the battery service test. The acceptance criteria, in the form ofa test shutdown criterion at 111 volts, had no basis in any design document. The battery test acceptance criteria failed to consider the minimum battery terminal voltage used to determine the acceptable operation ofsafety-related de equipment as documented in calculation D-E-92-002, Rev.1, datedMarch 7,1995, as 117.6 volts.
L ADMISSION OR DENIAL OF THE ALLEGED VIOLATION Baltimore Gas and Electric Company denies the alleged violation as stated above, but does acknowledge that the calculation was not easily auditable.
II REASON FOR THE VIOLATION The battery for No. l A Emergesy Diesel Generator (EDG) was tested to a test shutdown criteria of 111 volts. This test was performed to specifications in Engineering Test Procedure (ETP)-94-017, Revision 0. The test shutdown value in the ETP was not the same as design calculation D-E-92-002, Revision 1, which appeared to conclude that the minimum voltage is 117.6 volts.
Further research since the NRC Engineering and Corrective Action Inspection has revealed that design documents (Startup Acceptance Criteria and Tolerances, and the design specification for the No, l A EDG battery) also call for a minimum battery voltage of 111 volts.
While ETP-94-017 is written only for No. l A EDG, design calculation D-E-92-002 was created to consider both No. l A EDG and No. OC EDG. Number OC EDG has a long cable in the diesel output breaker closing circuit that requires an inaeased battery voltage to overcome the voltage drop. An interposing relay is installed in the No. l A EDG control circuit, which makes this increased voltage unnecessary for that diesel output breaker closing circuit. The calculation was not annotated to indicate that No. l A EDG does not need the higher voltage. The " bounding" nature of the design calculation was not obvious during the NRC inspection, and the difference in the control circuits for the two diesels was not described to the inspector.
Therefore, ETP-94-017, Revision 0, does use the test criteria called for by design documents and the voltage is sufficient to acceptably operate the safety-related direct current equipment on No. l A EDG.
III CORRECTIVE ACTION TIIAT HAS BEEN TAKEN AND RESULTS ACIHEVED Baltimore Gas and Electric Company reanalyzed the specific case for No.1 A EDG and verified that a minimum voltage standard of 11 I volts is correct.
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l A7TACHMENT (1)
NRC REGION I INSPECTION REPORT NOS. 50-317/98-80 AND 0-318/98-80 1
VIOLATION 98-80-03 IV CORRECTIVE STEPS THAT WH I BE UNDERTAKEN TO AVOID FURTHER VIOLATIONS Baltimore Gas and Electric Company will annotate calculation D-E-92-002 to add clarifying information about the difference between No. I A EDG and No. 0C EDG, and show the actual minimum voltage for the No. l A EDG direct current system.
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L__________________________.
ATTACIIMENT (2) l NRC REGION 1 INSPECTION REPORT NOS. 50-317/98-80 AND 0-318/98-80 VIOLATION 98-80-05
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B.
10 CFR Part 30, Appendix B, Criterion XVI, Corrective Actions requires in part: " Measures l
shall be established to assure that conditions adverse to quality, such asfailures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identifiedandcorrected. "
Contrary to the above, between December 29,1997, andJa uary 12,1998, two problems with the speed switch ofemergency diesel generator (EDG) 2B, which afected safetyfunctions and operability, were identified but were not properly resolved and corrected.
On December 29,1997, the local speed indicator (tachometer)for EDG 2Bfailed to zero (0) while the engine was running at 900 RPM, but BG&Efailed to identify the cause and correct the problem and improperly declared the diesel generator operable. Furthermore, following post maintenance testing on January 12,1998, BG&Efailed to idennfy and correct problems with a failed speed switch which caused the diesel to be declared inoperable.
L ADMISSION OR DENIAL OF THE AlI FGED VIOLATION Baltimore Gas and Electric Company accepts the violation.
II REASON FOR THE VIOLATION A.
Baltimore Gas and Electric Companyfailed to identify the cause and correct the problem j
with EDG No. 2B speed indicator and improperly declared the diesel generator operable.
During a December 29,1997 surveillance test procedure on EDG No. 2B, ep rators noticed that the local speed indica'.. had failed. Operations notified Plant Engineering, who in turn notified Electrical Maintenance. The system manager observed that the EDG had started normally and was operating at normal load with no unexpected alarms or other indications, except for the loss oflocal speed indication.
The system manager reviewed failure modes and plant experience and considered the fact the EDG started normally except for the failed local speed indication. He concluded the most likely cause for the loss of speed indication was failure of the tachometer generator. A failure of a tachometer generator does not affect the EDG's safety function, so the tachometer generator troubleshooting was scheduled as routine maintenance and the diesel generator was declared operable.
On January 12,1998, during an EDG slow start, operators noticed the " Auto Start Blocked" alarm did not clear as expected, nor did Relay LSA energize.
Disassembly and inspection of the speed switch adapter revealed the adapter failed when a spring clip holding the drive pin in position failed, allowing the drive pin to drop out of position and become disengaged. The use of a spring clip was a new configuration by the manufacturer that was not available in the manufacturer's technical inf,rmation. The failure of the adaptor caused failure oflocal speed indication, the failure of the " Auto Start Blocked" alarm to clear and the failure of the Relay LSA to energize.
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ATTACIIMENT (2)
NRC REGION 1 INSPECTION REPORT NOS. 50-317/98-80 AND 0-318/98-80 VIOLATION 98-80-05 B.
Baltimore Gas and Electric Companyfailed to identify and correct problems with afailed speedswitch that caused the diesel to be declared inoperable.
During the slow start of EDG No.2B on January 12, 1998, Electrical Maintenance technicians observed chattering of Relay LSA at around 300 rpm. The chattering was observed for several seconds e.s the EDG came up to about 500 rpm. The technicians discussed the chattering and decided it was unusual but did not represent an out-of-specification condition. They discussed the chattering with their supervisor ana concluded that it seemed to be only associated with engine operation at about 300 rpm. This was an engine speed they had not previously observed, and they concluded that the noise could be from vibration at that speed.
Later the same day, operators received an EDG No. 2B engine low-temperature alarm.
Troubleshooting revealed that the jacket coolant and keep-warm lubricating oil pumps had tripped on thermal overload. The most likely cause for the motor trips was a thermal overload created by multiple in-rush current loading. The current over-loading was probably caused by the relay chattering.
III CORRECTIVE ACTION TIIAT IIAS BEEN TAKEN AND RESULTS ACIIIEVED Other speed switch adaptors onsite have been inspected to ensure the spring clip adaptors are not degraded. No degradation was found.
IV CORRECTIVE STEPS TIIAT WILL BE UNDERTAKEN TO AVOID FURTIIER VIOLATIONS A.
System managers and system engineers will be trained on the importance of validating assumptions.
B.
A preventive maintenance program will be established for the purpose of inspecting EDG speed switch adaptor spring clips.
C.
Maintenance personnel will be trained on analytical troubleshooting techniques directed at verifying assumptions and identifying potential problems.
D.
Vendor techmcal manual held at the site will be updated to show the new pin configuration.
E.
A root cause investigation has been initiated.
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