BP to shut Whiting, Indiana hydrotreater for up to 42 days of work-source

(Adds information on crude unit shutdown)

NEW YORK, Aug 13 (Reuters) - BP Plc plans to shut down a jet hydrotreater at its 413,500 barrel-per-day refinery in Whiting, Indiana in the second week of September for up to 42 days of planned maintenance, according to a person familiar with the plant's operations.

The start date may get moved up, however, due to the recent and unexpected shutdown of the plant's largest crude unit, the source said Thursday, adding it could be down for up to two months as it is repaired.

The company discovered leaks in piping connected to the 240,000 bpd crude unit, called Pipestill 12, and shut the unit down on Saturday.

Currently, repairs are expected to take at least a month, sources have told Reuters. But until the inspections are finished, it will not be clear how long it will take to repair damaged piping, sources said on Thursday.

BP continues to run the refinery at about 165,000 bpd or 40 percent of its rated capacity as two smaller CDUs remain in operation.

Pipestill 12 was the centerpiece of a $4 billion refit of the refinery to run more sour crude from Alberta's tar sands fields. The rebuilt Pipestill 12 came online in July 2013.

The company did not immediately respond to requests for comment. (Reporting by Jessica Resnick-Ault and Jarrett Renshaw; Editing by Jonathan Oatis)