ENS 42187
ENS Event | |
|---|---|
23:00 Dec 2, 2005 | |
| Title | Reactor Power Operation in Excess of Operating License Condition |
| Event Description | This notification is being made pursuant to Braidwood Station Unit 1, Operating License Condition 2.G, which requires a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> notification to the NRC Operations Center for reactor power operation in excess of 3586.6 megawatts thermal (100 percent rated power), i.e., a violation of Operating License Condition 2.C (1)- Braidwood Station will, following this notification, provide a written report within thirty days in accordance with the procedures described in 10 CFR 50.73(b), (c), and (e).
Braidwood Station, Unit 1 experienced a Feedwater temperature transient on November 18, 2004, which caused reactor power to momentarily increase and peak at approximately 101.2% as indicated on the excore nuclear instrumentation system. The duration that reactor power remained above 100% was approximately one minute. Subsequent to the event, a number of peer reviews were conducted to validate that power did not exceed 102%. The results of these reviews questioned the methodology used to determine the power level at the time of the transient. Industry was consulted regarding methodologies appropriate for power level measurement during transient conditions. At 1700 on December 2, 2005, an independent Exelon task force concluded, using a conservative methodology, that reactor power level during this transient did exceed 100% for approximately one minute and was limited to a peak of approximately 103.5% and that the appropriate reports, as specified in the Operating License, should be initiated. This overpower transient, caused by the loss of a Feedwater heater string, is bounded by the Feedwater design basis transient described and analyzed in UFSAR, Section 15.1.1, "Feedwater System Malfunctions Causing a Reduction in Feedwater Temperature, therefore, the event did not place Braidwood Unit 1 in an unanalyzed condition that significantly degraded plant safety. No safety limits were exceeded and there was no impact on the health and safety of the public. The licensee has notified the Resident Inspector. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Braidwood  Illinois (NRC Region 3) | |
| Reporting | |
| Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+13.42 h0.559 days <br />0.0799 weeks <br />0.0184 months <br />) | |
| Opened: | Mike Deboard 12:25 Dec 3, 2005 |
| NRC Officer: | Ronald Harrington |
| Last Updated: | Dec 3, 2005 |
| 42187 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 528022017-06-12T14:14:00012 June 2017 14:14:00
[Table view]Other Unspec Reqmnt, 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification for Discharge of Circulating Water ENS 476372012-02-03T06:00:0003 February 2012 06:00:00 Other Unspec Reqmnt ENS 467122011-03-30T20:38:00030 March 2011 20:38:00 Other Unspec Reqmnt Discovery of After-The-Fact Emergency Condition (Unusual Event) ENS 421872005-12-02T23:00:0002 December 2005 23:00:00 Other Unspec Reqmnt Reactor Power Operation in Excess of Operating License Condition ENS 405592004-03-01T22:00:0001 March 2004 22:00:00 Other Unspec Reqmnt 24-Hour Condition of License Report Involving Potential Violation of Maximum Power Level ENS 401302003-09-03T12:30:0003 September 2003 12:30:00 Other Unspec Reqmnt 24-Hour Report Required by License Condition -- Potential Violation of Maximum Power Level ENS 401232003-08-31T06:32:00031 August 2003 06:32:00 Other Unspec Reqmnt 24-Hour Condition of License Report Involving Potential Violation of Maximum Power Level 2017-06-12T14:14:00 | |