ENS 54234
ENS Event | |
|---|---|
08:30 Jun 27, 2019 | |
| Title | Automatic Transfer of 4-Kv Vital Bus from Auxiliary to Startup Power |
| Event Description | This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) regarding an invalid Engineered Safety Feature actuation signal.
On June 27, 2019, at 0130 hours0.0015 days <br />0.0361 hours <br />2.149471e-4 weeks <br />4.9465e-5 months <br /> Pacific Daylight Time (PDT), with Unit 2 operating at 100 percent power, the U2 4-kV Vital Bus F was automatically transferred from its auxiliary power to its startup power due to an invalid loss of bus voltage signal. The cause of the invalid signal was due to a test jumper that was inadvertently left in place during surveillance testing. As a result, one auxiliary saltwater pump started and two containment fan cooler units started in slow speed. At 1245 PDT, Vital Bus F was transferred back from startup power to auxiliary power which is the normal plant operating configuration. This event was entered into the Diablo Canyon Power Plant corrective action program for resolution. This event did not result in any adverse impact on the health and safety of the public. The plant responded as expected. In accordance with 10 CFR 50.73(a)(1), a telephone notification is being made in lieu of submitting a written Licensee Event Report. The licensee has notified the NRC Senior Resident Inspector. |
| Where | |
|---|---|
Diablo Canyon  California (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1348.32 h56.18 days <br />8.026 weeks <br />1.847 months <br />) | |
| Opened: | David N. Madsen 12:49 Aug 22, 2019 |
| NRC Officer: | Brian P. Smith |
| Last Updated: | Aug 22, 2019 |
| 54234 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 567812023-08-08T18:07:0008 August 2023 18:07:00
[Table view]10 CFR 50.73(a)(1), Submit an LER 60 Day Notification for an Invalid Specified System Actuation ENS 542342019-06-27T08:30:00027 June 2019 08:30:00 10 CFR 50.73(a)(1), Submit an LER Automatic Transfer of 4-Kv Vital Bus from Auxiliary to Startup Power ENS 455852009-11-22T05:13:00022 November 2009 05:13:00 10 CFR 50.73(a)(1), Submit an LER Unexpected Automatic Start of the 2-1 Emergency Diesel Generator (Edg) ENS 436772007-10-01T02:58:0001 October 2007 02:58:00 10 CFR 50.73(a)(1), Submit an LER Unexpected Automatic Start of the 2-1 Emergency Diesel Generator (Edg) 2023-08-08T18:07:00 | |