05000445/LER-2002-003, Unexpected Auto Start of Train B Emergency Diesel Generator
| ML023470021 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 12/05/2002 |
| From: | Walker R TXU Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 10010, CPSES-200203917, TXX-02182 LER 02-003-00 | |
| Download: ML023470021 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(b)(3)(iv)(B) |
| 4452002003R00 - NRC Website | |
text
ATXU Afa TXU Energy Comanche Peak Steam Electric Station PO Box 1002 (E01)
Glen RoseTX 76043 Tel 254 897 8920 Fax: 254 897 6652 lance.terry@txu corn C. Lance Terry Senior Vice President &
Principal Nuclear Officer Ref: 10CFR50.73(a)(2)(iv)
CPSES-200203917 Log # TXX-02182 File # 10010 December 5, 2002 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-445 ACTUATION OF SPECIFIED SYSTEM:
EMERGENCY DIESEL GENERATOR LICENSEE EVENT REPORT 445/02-003-00 Gentlemen:
Enclosed is Licensee Event Report (LER) 02-003-00 for Comanche Peak Steam Electric Station Unit 1, "Auto start of the CPSES Unit 1 train B emergency diesel generator."
This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2.
o/9-
M TXU TXX-02182 Page 2 of 2 Sincerely, TXU Generation Company LP By:
TXU Generation Management Company LLC, Its General Partner C. L. Terry Senior Vice President and Principal Nuclear Officer By:
4 e
g'zVg ger D. Walker Regulatory Affairs Manager JDS/js Enclosures c -
E. W. Merschoff, Region IV W. D. Johnson, Region IV D. H. Jaffe, NRR Resident Inspectors, CPSES
Fne-Imi irp tn TXX-0l1 A2 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (7-2001).
EXPIRES 0713112004
, the NRC may not conduct or sponsor and a person is not required to respond to. the information collection.
Facility Name (I)
Docket Number (2)
Page (3 COMANCHE PEAK STEAM ELECTRIC STATION UNIT I 05000445 1 OF 5 Title (4)
AUTO START OF THE CPSES UNIT 1 TRAIN B EMERGENCY DIESEL GENERATOR Event Date (5)
LER Number (6) port Date (7)
Other Facitnies Involved (8)
Month Day Year Year Sequential Revision Month Day Year Facilty Namne Docket Numbers I
Number1 Number CPSES UNIT 2 05000446 10 07 0
02 2 003 00 12 05 02 05000 Operating 0reportisubmitted psuant tohe ruirement) of 03CFR (Checkallthatapply) 0(I)
Mode (9) 6 L 20.2201(b) f J20.2203(a)(3)(i) 50 73(a)(2)(i)(C)
-[50.73(a)(2)(vit)
Power I
LevelI
'n
- - 1'1sl Ad sCn '71f.'WMlAWA
';73Ar~o.i 20.2203(a)(1) 20.2203(a)(4) 50 73(a)(2)(n)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50 36(c)(2)(i)(A) 50 73(a)(2)(tli) 50 73(a)(2)(ix)(A) 20.2203(a)(2)(it) 50 36(c)(1)(ii)(A)
X 50 73(a)(2)(iv)(A) 50.72(a)(2)(x) 20.2203(a)(2)(iit) 50 36(c)(2) 50 73(a)(2)(v)(A)
=
73.71 (a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(i) 50 73(a)(2)(v)(B) 73.71 (a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50 73(a)(2)(v)(C)
OTHER 20 2203(a)(2)(vi) 50 73(a)(2)(i)tB) 50.73(a)(2)(vD)
Specify in Abstrac below or in =
(If more space is required. use addilnal eopies of NRC Foem 366A) (17)
I.
DESCRIPTION OF REPORTABLE EVENT A.
REPORTABLE EVENT CLASSIFICATION
An event or condition that resulted in valid actuation of any system listed in 10CFR50.73 (b)(3)(iv)(B). Specifically, an emergency diesel generator automatically started.
B.
PLANT OPERATING CONDITIONS PRIOR TO THE EVENT On October 7, 2002, Comanche Peak Steam Electric Station (CPSES) Unit 1 was in Mode 6 with the reactor cavity water level > 23 feet above the vessel flange. Core off-load was in progress with approximately one third of the core off-loaded. Core decay heat was being removed by train B of the Residual Heat Removal system. Unit 2 remained at power throughout the event.
C.
STATUS OF STRUCTURES, SYSTEMS, OR COMPONENTS THAT WERE INOPERABLE AT THE START OF THE EVENT AND THAT CONTRIBUTED TO THE EVENT There were no inoperable structures, systems, or components that contributed to the event.
D.
NARRATIVE SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On October 07, 2002, at 0936, during 345 KV switchyard east bus relay testing, an unexpected pickup of a relay contact occurred which tripped breakers resulting in de-energizing Unit 1 6.9KV non-safeguards electrical busses and caused the Unit 1 6.9KV safeguards busses to transfer to the alternate power source. The Unit 1 train B emergency diesel generator (EIIS:(DG)) 1-02 unexpectedly auto started while, as designed, the bus re-energized to station transformer XST1. Both Spent Fuel Pool pumps and the operating Residual Heat Removal pump were tripped. The blackout sequencer (BOS) actuated which caused several components to load shed and others to auto re-start as designed. The fuel assemblies in transit were secured in safe locations and core alterations were stopped. The plant operators responded to the loss of normal power to the train B bus and restored equipment shed from the busses by the momentary undervoltage condition.
(If nmore space is required, use addisonal copies of NRC Fort 366A) (17)
Residual Heat Removal (RHR) shutdown cooling was restored on the train B RHR pump at 0944 and Spent Fuel Pool cooling restored at 0946. The batteries normally providing backup DC power to the normal (non-safeguards) breaker controls were undergoing replacement at the time, complicating recovery of the non-safeguards busses. Normal plant power was restored at 1112 and core off-load resumed at 1319.
E.
THE METHOD OF DISCOVERY OF EACH COMPONENT OR SYSTEM FAILURE, OR PROCEDURAL OR PERSONNEL ERROR Control board indicators and alarms alerted the Reactor Operator (Utility, Licensed) that the train B emergency diesel generator 1EA2 (EIIS:(DG)) auto started.
H.
COMPONENT OR SYSTEM FAILURES A.
FAILURE MODE, MECHANISM, AND EFFECTS OF EACH FAILED COMPONENT The emergency diesel generator auto start in response to the bus transfer was unexpected.
Troubleshooting determined that the time delay relay 27-2X/1EA2 (EIIS:(2)) was operating erratically.
B.
CAUSE OF EACH COMPONENT OR SYSTEM FAILURE Performance of multiple tests on the time delay relay 27-2X/IEA2 (EIIS:(2)) determined that the time delay relay degraded to a point where repeatability was lost.
C.
SYSTEMS OR SECONDARY FUNCTIONS THAT WERE AFFECTED BY FAILURE OF COMPONENTS WITH MULTIPLE FUNCTIONS Not applicable -- No failures of components with multiple functions have been identified.
D.
FAILED COMPONENT INFORMATION
Manufacturer: Tyco Electronics Model No. E7012PA004 Agastat relay NRC FORIM 366A (1-2001)
Enclosure to TXX-02182 NRC FORMI 366A U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
Facility Nanie ()
Docket LER Number (6)
Page(3)
Year Sequential Revision COMANCHE PEAK STEAM ELECTRIC STATION UNIT I 05000445 0
Number Number 05045 02H o003 HooI 4OF 5 NARRATIVE (If more space is required, use additional copies of (If mnre space is required. use additional copies of NRC Form 366A) (17) slow to pick up allowing the 27-2XI/lEA2 relay to time out as designed, and started the train B emergency diesel generator.
V.
CORRECTIVE ACTIONS
The time delay relay 27-2X/1EA2 was replaced with a new relay. The new relay was recalibrated and is within design specifications. Additional relays in associated circuits were checked and found to be functioning within design requirements.
VI.
PREVIOUS SIMILAR EVENTS
There have been other events involving the start of an emergency diesel generator. However, details/causes are sufficiently different from the event described in this LER such that the previous corrective actions could not have prevented this event.
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