# NRC CAL – NOV (White)
> **EA-11-110** · CAL · Issued 2011-08-17 · Reactor Licensees
## Action
- **EA Number:** EA-11-110
- **Licensee:** NOV (White)
- **Category:** Reactor Licensees
- **Action type:** CAL
- **Date issued:** 2011-08-17
## Description

On August 17, 2011, the NRC issued a Notice of Violation to Northern States Power Company for a violation associated with a White Significance Determination Process finding. The violation involved the failure to maintain the direct current electrical power subsystems operable in Modes 1 through 4, as required by Technical Specification 3.8.4. Specifically, from December 21, 1994 to approximately October 22, 2010, all battery chargers in Unit 1 were susceptible to a common mode failure under design basis accident conditions. Under those conditions, the battery chargers would stop providing an output, or "lock-up," when their alternating current input voltage dropped below their nameplate minimum voltage at the battery charger motor control center.

## Source
- [Full enforcement letter (PDF)](https://www.nrc.gov/docs/ML1122/ML112290087.pdf)
- [NRC Reactor Licensees index](https://www.nrc.gov/reading-rm/doc-collections/enforcement/actions/reactors/)
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