05000456/LER-2007-001, Re Reactor Trip Following a 345 Kv Transmission Line Lightning Strike
| ML072400074 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 08/27/2007 |
| From: | Coutu T Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BW070066 LER 07-001-00 | |
| Download: ML072400074 (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) 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 |
| 4562007001R00 - NRC Website | |
text
10 CFR 5013 August 27, 2007 BW070066 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:
Licensee Event Report Number 2007-001-00 Unit 1 Reactor Trip Following a 345 Ky Transmission Line Lightning Strike The enclosed Licensee Event Report (LER) is being submitted in accordance with 10 CFR 50.73, Licensee event report system, paragraph (a)(2)(iv)(A). 10 CFR 50.73(a) requires an LER to be submitted within 60 days following discovery of the event, therefore, this report is being submitted by August 27, 2007.
There are no commitments contained in the attached report. Should you have any questions concerning this submittal, please contact Mr. David Gullott, Regulatory Assurance Manager, at (815) 417-2800.
Respectfull
~~~~dntt Braidwoo ion
Enclosure:
LER Number 2007-001-00
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION 6-2004)
LICEE EVENT REPORT (LER)
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APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 06/30/2007
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- 1. FACILITY NAME Braidwood Station, Unit 1
- 2. DOCKET NUMBER
- 3. PAGE 05000456 1
of 3
L TITLE Unit 1 Reactor Trip Following a 345 Ky Transmission Line Lightning Strike
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL
~
MONTH DAY YEAR FACILITY NAME N/A DOCKET NUMBER N/A 06 27 2007 2007 001 00 08 27 2007
~ACILlTYNAME N/A DOCKET NUMBER N/A
- 9. OPERATING MODE 1
- 11. THIS REPORT IS SUBMITTED PURSUANTTO THE REQUIREMENTS OF 10 CFR~:(Check all that apply) o 20.2201(b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(i)(c) 0 50.73(a)(2)(vii) 0 20.2201(d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viii)(A) o 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B) o 20.2203(a)(2)(i) 0 50.36(c)(1)(i)(A) 0 50.73(a)(2)(iii) 0 50.73(a)(2)çx)(A) 0 20.2203(a)(2)(ii) 0 50.36(c)(1)(ii)(A)
N 50.73(a)(2)Øv)(A) 0 50.73(a)(2)(x) o 20.2203(a)(2)(iii) 0 50.36(c)(2) 0 50.73(a)(2)(v)(A) 0 7311 (a)(4) o 20.2203(a)(2)(iv) 0 50.46(a)(3)Oi) 0 50.73(a)(2)(v)(B) 0 73.71 (a)(5) 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(c) 0 OTHER o 20.2203(a)(2)(vi) 0 50.73(a)(2)Ø)(B) 0 50.73(a)(2)(v)(D)
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Safety Consequences
There were no safety consequences impacting plant or public safety as a result of this event. All safety related systems, structures and components operated normally during this event.
The actuation of the Reactor Protection System was valid for this plant condition and occurred without incident. The reactor trip is designed to prevent Departure from Nucleate Boiling caused by the reduction in total core flow. This event is explicitly described under Updated Final Safety Analysis Report section 15.3.1, Partial Loss of Reactor Coolant Flow.
During the reactor shutdown, all required safety systems responded appropriately. There was no loss of any function that would have prevented fulfillment of actions necessary to 1) Shutdown the reactor and maintain it in a safe shutdown condition, 2) Remove residual heat, 3) Control the release of radioactive material, or 4) Mitigate the consequences of an accident.
For a short period of time following the reactor shutdown, Unit 1 entered Limiting Condition of Operation Action Requirement (LCOAR) 3.7.5, Condition A for the 1 B Auxiliary Feedwater Pump when the diesel oil Day Tank level dropped to 74%. Operators were dispatched to add fuel to the Day Tank to exit the LCOAR. Although the lB AFW pump was declared inoperable during this time, the pump remained in operation until it was no longer needed to maintain steam generator levels. The 1 B LCOAR was entered at 10:07 am and exited at 10:45 am when the Day Tank low-level alarm cleared. The 1 B AFW pump day tank level was above the Technical Specification limit prior to the event so the lB AFW pump was capable of performing its design function.
This event did not result in a safety system functional failure.
Corrective Actions
Corrective actions in response to this issue include:
Revising identified procedures to perform monitoring of the integrity of critical fuses within trip-sensitive protective relaying circuits, and Implementing design changes to eliminate the identified vulnerability from the RCP protective relaying system, or if design changes are not appropriate, developing alternate actions to address the vulnerability.
Previous Occurrences
There have been no similar Licensee Event Report events at Braidwood Station in the last three years.
~ Component Failure Data:
Manufacturer Nomenclature Model Mfp. Part Number N/A N/A N/A N/APRINTED ON RECYCLED PAPER