05000373/LER-2011-001, For LaSalle County Station, Unit 1 Re Automatic Reactor Scram Due to Main Power Transformer C Phase Electrical Fault
| ML110890949 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 03/25/2011 |
| From: | Karaba P Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA11-013 LER 11-001-00 | |
| Download: ML110890949 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3732011001R00 - NRC Website | |
text
Nuclear LaSalle Generating Station www.exeloncorp.com 2601 North 21st Road Marseilles, IL 61341-9757 10 CFR 50.73 RA11-013 March 25, 2011 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Unit 1 Facility Operating License No. NPF-1 1 NRC Docket No. 50-373
Subject:
Licensee Event Report 2011-001-00 In accordance with 10 CFR 50.73(a)(2)(iv)(A), Exelon Generation Company (EGC), LLC, is submitting Licensee Event Report Number 2011-001-00.
There are no regulatory commitments in this report. Should you have any questions concerning this report, please contact Mr. Terrence W. Simpkin, Regulatory Assurance Manager at (815) 415-2800.
Respectfully, Peter J. Karaba Plant Manager LaSalle County Station
Enclosure:
Licensee Event Report cc:
Regional Administrator - NRC Region III NRC Senior Resident Inspector-LaSalle County Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE LaSalle County Station Unit 1 05000373 1
OF 3
- 4. TITLE Automatic Reactor Scram Due to Main Power Transformer "C" Phase Electrical Fault
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
FACILITY NAME DOCKET NUMBER 02 01 2011 2011 01 00 03 25 2011
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §:
(Check all that apply) q 20.2201(b) q 20.2203(a)(3)(i) q 50.73(a)(2)(i)(C) q 50.73(a)(2)(vii) 1 q 20.2201(d) q 20.2203(a)(3)(ii) q 50.73(a)(2)(ii)(A) q 50.73(a)(2)(viii)(A) q 20.2203(a)(1) q 20.2203(a)(4) q 50.73(a)(2)(ii)(B) q 50.73(a)(2)(viii)(B) q 20.2203(a)(2)(i) q 50.36(c)(1)(i)(A) q 50.73(a)(2)(iii) q 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL q 20.2203(a)(2)(ii) q 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x) q 20.2203(a)(2)(iii) q 50.36(c)(2) q 50.73(a)(2)(v)(A) q 73.71(a)(4) 100 q 20.2203(a)(2)(iv) q 50.46(a)(3)(ii) q 50.73(a)(2)(v)(B) q 73.71(a)(5) q 20.2203(a)(2)(v) q 50.73(a)(2)(i)(A) q 50.73(a)(2)(v)(C) q OTHER q 20.2203(a)(2)(vi) q 50.73(a)(2)(i)(B) q 50.73(a)(2)(v)(D)
Specify in Abstract below or in
E. CORRECTIVE ACTIONS
Corrective Actions
The C-phase bushing, the C corona ring and the MPT mechanical relief valve were replaced A comprehensive engineering strategy plan to significantly reduce the potential for high voltage bushing flashover will be developed A subject matter expert review will be conducted of the cleaning frequency and methodology guideline to determine best practices for maintaining bushing cleanliness across high risk seasonal salt and snow accumulations Corrective Action to prevent Recurrence:
MPT bushings will be replaced with a more robust anti-flashover design that exceeds minimum Basic Insulation Level (BIL) rating, adding more margin to the creep length
F. PREVIOUS OCCURRENCES
LER 05000373/2009-01-00 On May 21, 2009, at 1635 CDT, LaSalle Unit 1 automatically scrammed from 100% power. The scram was due to a generator lockout signal caused by a failure of the surge arrestor on the A phase of the 1W MPT. The cause of surge arrestor failure was determined to have been due to a manufacturer's defect.
G. COMPONENT FAILURE DATA
Manufacturer: Westinghouse (W120)
Model: Type 0