Why is Plant Hatch Unit 1 running at well below capacity?

Saturday 19 Jan 2013 that nuclear plant was
at 100%, according to the NRC,
yet Sunday it was down to 45%, then 40% Monday and 64% today.
What's going on at Hatch 1?
And what happened to nuclear supposedly being 24/7?
There's no
event report
about this from the NRC;
the last item the NRC has on Hatch 1 seems to be
from 2003.
Southern Company provides
no information on this event.
Another source (Platts, 4 January 2013)
says Hatch 2 (and Vogtle 2) are to refuel in the first half of this year,
among
Fifty-six US nuclear units to shut for refueling in 2013.
But Hatch 1 is not on that list,
and a similar Hatch 1 brownout happened 5 and 6 January: