Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 49287 | 16 August 2013 02:36:00 | At 1824 PDT on August 15, 2013, Unit 1 experienced a loss of startup power due to a failure of Startup Transformer 1-1 load tap changer. This loss caused a valid auto-start signal to all three emergency diesel generators and they all started successfully. At 1921, all EDGs were shutdown and returned to standby per plant procedures. As a result of the loss of startup power, power was also lost to site service buildings. ERDS was lost but compensatory measures are in place to transmit required data via the ENS line if required. The plant is in a 72-hr. shutdown LCO action statement under T.S. 3.8.1 for the loss of one of three qualified circuits. The two other qualified circuits (vital power via auxiliary transformers and the EDGs) remain operable. The licensee has notified the NRC Resident Inspector. |
| ENS 49148 | 26 June 2013 01:59:00 | At 2158 PDT, plant personnel identified a through-wall leak in a Diablo Canyon Power Plant Unit 1 socket weld inside containment that provides a flow path to a relief valve that protects a common portion of both trains of the Residual heat Removal (RHR) system. The as-found condition did not comply with the requirements of equipment control guideline 7.6 and the ASME acceptance criteria. PG&E accordingly declared both Unit 1 trains of RHR inoperable and initiated plant shutdown at 2237 PDT in accordance with requirements of Technical Specification 3.0.3. PG&E will complete shutdown to Mode 4 and will perform repairs to restore compliance with ASME code requirements. The licensee notified the NRC Resident Inspector. * * * UPDATE AT 1303 EDT ON 6/26/13 FROM WESLEY FIANT TO PETE SNYDER * * * Pacific Gas and Electric Company is submitting an update based on a press release issued at 0915 PDT detailing the above information to local television, newspaper, and radio media outlets. San Luis Obispo County and State of California Offices of Emergency Services have already been notified. The licensee notified the NRC Resident Inspector. Notified R4DO (Pick). |
| ENS 49147 | 24 June 2013 22:07:00 | At 16:15 PDT on 6/24/13, an operator performing a post-event annunciator alarm review of the event reported in EN #49143 identified that the operators the previous night had momentarily disabled all three Unit 1 emergency diesel generators, prior to restoring them to their automatic standby control alignment. Between 22:01:10 PDT and 22:02:54 PDT, on 6/23/13, less than the required minimum two diesel generators were available to automatically respond to a design basis accident. Due to the event reported in EN #49143, the start-up 230 kV power source was also unavailable at this time. At the time of this event the operators were in the procedurally guided process of placing the running diesel generator controls to manual, shutting down the running diesel generators, and returning them to the automatic standby control alignment. In this event the operators placed all the diesel generators in manual and shut them down before returning them to automatic control. During this time the operators would have responded to a plant event by returning the affected diesels to auto, whereupon the normal starting and loading sequence would have resumed in accordance with existing accident analyses. At the time of discovery all offsite and onsite power sources were operable. The licensee notified the NRC Resident Inspector. |
| ENS 48171 | 9 August 2012 11:47:00 | At about 1000 PDT on August 9, 2012, Pacific Gas and Electric Company (PG&E) will disconnect the Diablo Canyon Power Plant (DCPP) Plant Data Network to the Emergency Operations Facility (EOF) and redirect the data via the Utility Data Network for hosting the emergency facility data systems. These systems include the Safety Parameter Display System, Plant Process Computer, Emergency Response Facility Display System, and Emergency Assessment and Response System in the EOF. PG&E expects to have the Emergency Response Data System and the EOF data network unavailable for about 8 hours. During this time, if needed, the TSC will have command and control once staffed, and will have classification, notification and dose assessment responsibility until the display systems are restored to the EOF. Also, if required, a dedicated licensed operator will be available in the control room to provide plant data to the NRC's Emergency Operations Center. DCPP is making this 8-hour, non-emergency notification under 10 CFR 50.72(b)(3)(xiii) as any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability. The licensee has notified the NRC Resident Inspector. |