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Entered date | Event description | |
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ENS 51173 | 23 June 2015 10:26:00 | At 0342 (CDT), as a result of severe weather conditions in the area, Exelon Generation Company, LLC (EGC) identified that the Emergency Notification System (ENS), Health Physics Network (HPN) phone systems, and their associated back-up system, the commercial phone system, had failed at Dresden Nuclear Power Station (DNPS). A loss of the primary phone system concurrent with the loss of the associated back-up system is a reportable condition in accordance with 10 CFR 50.72 (b)(3)(xiii) - Major Loss of Emergency Preparedness Capabilities. As a result of the failed communication systems, DNPS contacted the NRC to notify them of the issue and provided an alternate phone number for the Shift Manager for use until the systems were restored. As of 0743 (CDT), ENS, HPN, and the commercial phone systems were restored and verified to be working properly. The licensee notified the NRC Resident Inspector. |
ENS 50030 | 12 April 2014 13:24:00 | At 1012 CDT on April 12, 2014, Dresden Unit 2 automatically scrammed on TR-2 sudden pressure relay actuation. All rods inserted to their full-in positions. Following the reactor scram, the 'A' reactor recirculation pump did not run back to minimum speed automatically. Operators took action to run the recirculation pump to minimum speed manually. All other systems operated as expected. Reactor vessel inventory and pressure are being maintained in automatic. The cause of the scram was due to a trip of the sudden pressure relay for Main Power Transformer 2. Troubleshooting is in progress to determine the cause (of the trip of the sudden pressure relay). This condition is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. Normal offsite power remains available. There was no impact on Unit 3. The NRC Resident Inspector has been informed. |