ENS 50792
ENS Event | |
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18:27 Feb 6, 2015 | |
Title | Automatic Reactor Scram Due to Loss of Feedwater |
Event Description | At 1227 CST on 06 Feb 2015, Dresden Unit 2 automatically scrammed due to a Reactor Water Level transient. Set up activities for weekend maintenance were being performed on the feedwater system at the time of the event.
All rods inserted to their full-in positions. Systems operated as expected. Reactor vessel inventory and pressure are being maintained in normal control bands. The ultimate heat sink was maintained. The source of the transient was a loss of Feedwater Level Control and the reactor automatically scrammed on low reactor water level. Cause of the failure is under investigation. All three feed pumps tripped as a result of the transient. The 2B reactor feed pump was restored following the transient in accordance with station operating procedures. Level is being maintained with normal feedwater. High Pressure Coolant Injection initiated on a valid low-low reactor water level. Manual operator action was taken to prevent unneeded injection into the reactor coolant system. Group 2 Primary Containment and Group 3 Shutdown Cooling and Reactor Water Clean-up system isolations occurred as expected. Unit 2 and 2/3 [swing diesel] EDGs started as expected, but did not load onto their associated busses as offsite power was maintained. The licensee has notified the NRC Resident Inspector. |
Where | |
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Dresden Illinois (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
Time - Person (Reporting Time:+-1.57 h-0.0654 days <br />-0.00935 weeks <br />-0.00215 months <br />) | |
Opened: | Ryan Sears 16:53 Feb 6, 2015 |
NRC Officer: | Daniel Mills |
Last Updated: | Feb 6, 2015 |
50792 - NRC Website
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Unit 2 | |
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Reactor critical | Critical |
Scram | A/R |
Before | Power Operation (100 %) |
After | Hot Shutdown (0 %) |
Dresden with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge | |
WEEKMONTHYEARENS 559882022-07-12T13:03:00012 July 2022 13:03:00
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