05000456/LER-2005-003, Regarding Licensed Maximum Power Level Exceeded Due to Feedwater Heater Transient
| ML060550075 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 01/03/2006 |
| From: | Polson K Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BW060002 LER 05-003-00 | |
| Download: ML060550075 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(iv)(A), System Actuation 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 |
| 4562005003R00 - NRC Website | |
text
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Exelon Generation Company, LLC Braidwood Station 35100 South Rt 53, Suite 84 Braceville, IL 60407-9619 www.exeloncorp.com Nuclear 10 CFR 50.73 January 3, 2006 BW060002 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Unit 1 Facility Operating License No. NPF-72 NRC Docket No. STN 50-456
Subject:
Submittal of Licensee Event Report Number 2005-003-00, Braidwood Unit 1 -
"Licensed Maximum Power Level Exceeded Due to Feedwater Heater Transient' The enclosed Licensee Event Report is being submitted in accordance with Braidwood Station Unit 1 License Condition 2.G due to violating license condition 2.C(1), "Maximum Power Level."
License Condition 2.G requires a report to be submitted within 30 days after discovery of the event.
Therefore, this report is being submitted by January 3, 2006.
There are no commitments contained in the attached report. Should you have any questions concerning this submittal, please contact Mr. Dale Ambler, Regulatory Assurance Manager, at (815) 4-17-2800.
Respectfully, Keith. Poison Site Vice President Braidwood Station
Enclosure:
LER Number 2005-003-00 cc:
Regional Administrator - Region IlIl NRC Braidwood Senior Resident Inspector jC--L
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the
- 1. FACILITY NAME DOCKET NUMBER
- 3. PAGE Braidwood, Unit 1 05000456 1 of 3
- 4. TITLE Licensed MaximLum Power Level Exceeded Due to Feedwater Heater Transient
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEUNIA JE FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER REV MONTH DAY YEAR N/A N/A FACILITY NAME DOCKET NUMBER 11 18 2004 2005 - 003 -
00 01 03 2006 N/A N/A
- 9. OPERATING MODE
- 1. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
E 20.2201(b)
D 20.22D3(a)(3)(i)
El 50.73(a)(2)(i)(C)
E 50.73(a)(2)(vii) 1 El 20.2201(d)
El 20.22D3(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A) o 20.2203(a)(1)
El 20.22D3(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
C_ 20.2203(a)(2)(i)
E 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 0 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
E 50.73(a)(2)(x) 0 20.2203(a)(2)(iii) 03 50.36(c)(2)
E 50.73(a)(2)(v)(A)
E3 73.71 (a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5) 99.9 0 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C) i OTHER El 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
E 50.73(a)(2)(v)(D)
Specify in Abstract below or in (If more space is required, use additional copies of NRC Form 366A) (17)
Cause of Event
The HI-2 switch on the 15A heater Magnetrol level control assembly was found partially actuated due to calibration issues. During the start of the normal calibration for the 15A level control assembly, the mechanical agitation due to the removal of a drain cap was sufficient to actuate the adjacent HI-2 switch contacts and isolate the extraction steam to the I5A and 15 B low pressure feedwater heaters.
The root cause for the initiating event was determined to be a lack of understanding for a potential adverse internal component interaction during the calibration of a level controller on the same level column as the Magnetrol level switches.
3. Safety Consequences
There were no safety consequences impacting plant or public safety as a result of this event. This was an analyzed condition. The November 18, 2004 overpower transient caused by a feedwater temperature transient was bounded by the feedwater design transient described and analyzed in Braidwood UFSAR, Section 15.1.1, "Feedwater System Malfunctions Causing a Reduction in Feedwater Temperature." The calculated overpower condition existed only during the transient (i.e., approximately one minute). The plant responded to the transient as designed, with a turbine overpower delta-temperature runback.
This event did not result in a safety system functional failure.
Corrective Actions
The corrective actions to prevent occurrence from the root cause evaluation completed in January 2005 included creation of a work package standard to ensure uniformity for alignment, adjustments and calibration of the tandem float Magnetrol level control assemblies.
Additional actions include developing and implementing a process to address, for overpower transient power changes such as feedwater temperature reductions, whether overpower conditions occurred, by correcting nuclear instrumentation system readings.
Previous Occurrences
There have been no previous occurrences of overpower due to feedwater heater transients. There have been three overpower events in the past three years:
Unit 1 Licensee Event Report 2004-001 Licensed Maximum Power Level Exceeded Due to Inaccuracies in Feedwater Ultrasonic Flow Measurements Unit 2 Licensee Event Report 2003-002 Licensed Maximum Power Level Exceeded Due to Inaccuracies in Feedwater Ultrasonic Flow Measurements Caused by Signal Noise Contamination Unit 1 Licensee Event Report 2003-002 Licensed Maximum Power Level Exceeded Due To An Error In A Westinghouse Supplied Calorimetric Calculation Constant
. Component Failure Data:
Manufacturer Nomenclature Model Mfg. Part Number N/A N/A N/A N/A