ENS 52452: Difference between revisions
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StriderTol (talk | contribs) (Created page by program invented by Mark Hawes) |
StriderTol (talk | contribs) (Created page by program invented by StriderTol) |
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| event date = 12/21/2016 11:20 CST | | event date = 12/21/2016 11:20 CST | ||
| last update date = 12/21/2016 | | last update date = 12/21/2016 | ||
| title = Unanalyzed Condition - 480V Bus Voltage Lower | | title = Unanalyzed Condition - 480V Bus Voltage Lower than Analyzed | ||
| event text = On October 8, 2016, it was initially discovered that the voltage tap changer settings for the 480V Shutdown Board Transformers 1-XFA-231-TS1A (TS1A) and 1-XFA-231-TS1B (TS1B) were incorrect (4160/480V instead of 3952/480V). This could potentially result in lower than minimum required voltages at the electrically downstream buses and equipment during a postulated loss of coolant accident coincident with design minimum voltage conditions. An initial Licensee Event Report (LER 50-259/2016-004-00) was submitted on December 7, 2016 following the initial review. This LER identified that a supplement would be required pending additional technical evaluation. While comprehensive analysis is not complete, the initial aggregate dynamic loading evaluation does not provide assurance that sufficient voltage would be available for various loading scenarios during postulated accident conditions. This condition was determined to have existed since a Unit 1 Design Change was implemented in 2004. | | event text = On October 8, 2016, it was initially discovered that the voltage tap changer settings for the 480V Shutdown Board Transformers 1-XFA-231-TS1A (TS1A) and 1-XFA-231-TS1B (TS1B) were incorrect (4160/480V instead of 3952/480V). This could potentially result in lower than minimum required voltages at the electrically downstream buses and equipment during a postulated loss of coolant accident coincident with design minimum voltage conditions. An initial Licensee Event Report (LER 50-259/2016-004-00) was submitted on December 7, 2016 following the initial review. This LER identified that a supplement would be required pending additional technical evaluation. While comprehensive analysis is not complete, the initial aggregate dynamic loading evaluation does not provide assurance that sufficient voltage would be available for various loading scenarios during postulated accident conditions. This condition was determined to have existed since a Unit 1 Design Change was implemented in 2004. | ||
This notification is being made pursuant to 10 CFR 50.72(b)(3)(ii), as any event or condition that resulted in the nuclear plant being in an unanalyzed condition that significantly degrades plant safety. | This notification is being made pursuant to 10 CFR 50.72(b)(3)(ii), as any event or condition that resulted in the nuclear plant being in an unanalyzed condition that significantly degrades plant safety. | ||
Latest revision as of 21:43, 1 March 2018
| Where | |
|---|---|
Browns Ferry  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+-0.42 h-0.0175 days <br />-0.0025 weeks <br />-5.75316e-4 months <br />) | |
| Opened: | David Renn 16:55 Dec 21, 2016 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Dec 21, 2016 |
| 52452 - NRC Website
| |