ENS 50859
ENS Event | |
|---|---|
17:01 Mar 3, 2015 | |
| Title | Automatic Reactor Trip Due to Main Power Transformer Bushing Short |
| Event Description | In accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A), this notification reports an automatic reactor trip on Byron Unit 1. The trip occurred following a trip of the Byron Unit 1 East Main Power Transformer (MPT). Initial indications appear that the MPT trip was caused by a large (~ 5 foot) section of ice that fell from a bus bar over the 1E MPT. This ice shorted out a MPT bushing, resulting in the unit trip. Reactor operators performed a manual start of the Auxiliary Feedwater System in response to the unit trip. All other safety systems responded as expected.
The plant trip occurred at 1101 CST on March 03, 2015. Unit 1 is presently in Mode 3 and stable. Unit 2, the opposite unit, is operating at 100% power and stable. This condition was entered into the Byron CAP Program. An investigation is in progress to determine the extent of required repairs, if any, required prior to unit restart. This event resulted in the actuation of the Reactor Protection System with a subsequent Reactor Trip and therefore, requires notification to the NRC within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of discovery in accordance with 10 CFR 50.72(b)(2)(iv)(B). This event resulted in the manual actuation of the Auxiliary Feedwater System and therefore, requires notification to the NRC within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of discovery in accordance with 10 CFR 50.72(b)(3)(iv)(A). This ENS call will be followed up with a Licensee Event Report (LER) within 60 days. All rods inserted during reactor trip, offsite power and emergency power sources are currently available and decay heat is being removed via the startup feedwater systems. No safety relief valves lifted as a result of the transient. The NRC Resident Inspector and the State of Illinois were notified. |
| Where | |
|---|---|
Byron  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-2.67 h-0.111 days <br />-0.0159 weeks <br />-0.00366 months <br />) | |
| Opened: | Charles Berger 14:21 Mar 3, 2015 |
| NRC Officer: | Jeff Herrera |
| Last Updated: | Mar 3, 2015 |
| 50859 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
Byron with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 540202019-04-22T18:24:00022 April 2019 18:24:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Initiation of the Auxiliary Feedwater System in Response to a Loss of Feedwater ENS 534912018-07-06T05:00:0006 July 2018 05:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Transformer Failure Causes Loss of Offsite Power to Unit 2 ENS 522952016-10-12T18:38:00012 October 2016 18:38:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Spurious Feedwater Isolation ENS 508592015-03-03T17:01:0003 March 2015 17:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Main Power Transformer Bushing Short ENS 499192014-03-15T16:02:00015 March 2014 16:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Momentary Loss of Shutdown Cooling Due to a Loss of Offsite Power ENS 488382013-03-21T00:51:00021 March 2013 00:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Loss of Generator Stator Cooling Water ENS 477082012-02-28T23:31:00028 February 2012 23:31:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Due to Loss of Offsite Power ENS 476442012-02-06T23:19:0006 February 2012 23:19:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Rps Actuation Due to Turbine Trip ENS 476242012-01-30T16:01:00030 January 2012 16:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unusual Event Due to Loss of Offsite Power Greater than 15 Minutes ENS 458672010-04-19T10:03:00019 April 2010 10:03:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Rps and Afw Actuation Signals While Shutdown in Mode 4 ENS 420632005-10-19T05:57:00019 October 2005 05:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Low 2 Steam Generator Water Level 2019-04-22T18:24:00 | |