'Bering Sea Gold' Star -- Busted for DUI ... Again

A star on Discovery Channel's "Bering Sea Gold: Under the Ice" has been popped for DUI ... again ... after driving at breakneck speeds and blowing almost twice the legal limit ... TMZ has learned.

Shawn Pomrenke was busted in Nome, Alaska ... it happened last month but we just learned of it.

Shawn was barreling down the highway at 102 MPH ... switching lanes without signaling according to the police report.

And get this ... cops say he blew a .156.

Anchorage cops impounded Shawn's car because he had been previously ordered NOT to drive without an Ignition Interlock Device ... and guess what wasn't installed?

As for why he was required to have the device ... Shawn was busted for DUI a year ago, after hitting a pedestrian and fleeing.

Shawn was sentenced to 180 days but served less than 2 weeks. He was released last week.