05000353/LER-2003-001, From Limerick Generating Station, Unit 2 Regarding Main Turbine High Vibration Manual Turbine Trip & Automatic Scram During Planned Shutdown
| ML031210521 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 04/25/2003 |
| From: | Braun R Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 03-001-00 | |
| Download: ML031210521 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition |
| 3532003001R00 - NRC Website | |
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1f Exelon Nuclear www exeloncorp corn Nuclear Limerick Generating Station P0 Box 2300 Sanatoga, PA 19464 1 OCFR50.73 April 25, 2003 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 2 Facility Operating License Nos. NPF-85 NRC Docket Nos. 50-353
Subject:
LER 2-03-001, Unit 2 Scram due to Main Turbine Manual Trip This Licensee Event Report (LER) addresses a Limerick Unit 2 unplanned automatic scram due to a manual trip of the main turbine as a result of a high vibration condition that developed during a planned plant shutdown.
Report Number:
2-03-001 Revision:
00 Event Date:
March 3, 2003 Discovered Date:
March 3, 2003 Report Date:
April 25, 2003 This LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(iv)(A).
If you have any questions or require additional information, please do not hesitate to contact us.
Sincerely, Robert C. Braun Vice President - Limerick cc: H. J. Miller, Administrator Region I, USNRC A. L. Burritt, USNRC Senior Resident Inspector, LGS
NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 3150-0104 EXPIRES 6-30-2001 (1-2001)
COMMISSION Estimated burden per response to comply with this mandatory information collection request 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> Reported lessons learned are incorporated into the licensing process and fed back to industry Send comments regarding burden estimate to the Records Management Branch (T-6 E6). US Nuclear Reigulatory CommissionWashington. DC 20555-0001,or by intemet LICENSEE EVENT REPORT (LER) e-mai to bjsl nrc goav and to the Desk Officer, Office of Information and Regulator Affairs, NEOB-10202 ( 1500104),Office of Management and Budget, WashingtonDC20503 If a (See reverse for required number of means used to impose information collection does not display a currently valid OMB control digitstcharacters for each block) number, the NRC may not conduct or sponsor, and a person is not required to respond tothe information collecionn FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE (3)
Limerick Generating Station, Unit 2 05000 353 1 OF 4
TITLE (4)
Main Turbine High Vibration Manual Turbine Trip nd Automatic Scram During Planned Shutdown EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
S FACILITY NAME DOCKET NUMBER MO DAY YEAR YEAR NUMB3ER NO MO DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 03 03 2003 2003 001 00 04 25 2003 05000 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE R.EQUIREMENTS OF 1 D ClF R (Check all that apply) (11)
MODE (9) 1 20 2201 (b) 20 2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50 73(a)(2)(ix)(A)
POWER 20 2201 (d) 20 2203(a)(4) 50 73(a)(2)(iii) 50 73(a)(2)(x)
LEVEL (10) 26__ 20 2203(a)(1)
_50 36(c)(1)(1)(A) x 50.73(a)(2)(iv)(A) 73 71 (a)(4) 20 2203(a)(2)(i) 50 36(c)(1)(i)(A) 50 73(a)(2)(v)(A) 73 71 (a)(5) 20 2203(a)(2)(i) 50 36(c)(2) 50 73(a)(2)(v)(B)
OTHER Specify in Abstract below or in 20 2203(a)(2)(iii) 50 46(a)(3)(ii) 50 73(a)(2)(v)(C)
(If more space is required, use addtional copies of (If more space is required, use additional copies of (If more space is required, use addibonal copies of NRC Formn 366A) (17)
Cause of the Event
The cause of the event was a light radial rub that developed at #3 bearing outboard oil seal due to the tight oil deflector gaps on the main turbine at.024 inches. In addition, the low-pressure turbine gland seal clearances were inadequate due to gland case misalignment. Also, operation at main condenser backpressures of less than 1.0 inches Hg contributes to initiation of rubs at the oil deflectors during main turbine startup and shutdown.
Corrective Action Completed The affected Unit 2 main turbine oil deflector gaps were resized to nominal.040 inches.
The affected Unit 2 low-pressure turbine gland seal clearances, #3 and #7, were restored to design values.
Operating procedures were revised to maintain main condenser backpressure above 1.5 inches Hg when less than 50% power.
Corrective Action Planned The affected Unit 1 main turbine oil deflector gaps will be resized to nominal.040 inches during the next refueling outage opportunity.
The affected Unit 1 low-pressure turbine gland seal clearances will be restored to design values as required during the next refueling outage opportunity.
The Unit 2 low-pressure turbine gland seals #4 and #5 clearances will be restored to design values during the next refueling outage opportunity.
Previous Similar Occurrences There were no previous occurrences of main turbine high vibration that resulted in a main turbine trip and subsequent automatic scram.
Component data:
Systemr TA (Main Turbine System)
Component:
TRB (Turbine)
Manufacturer:
1341 (Siemens)
Model number:
27-0119 LP