Sandia does weapons research, but it does more than just that. One of the main goals is indeed stockpile stewardship, and to that end Sandia produces a lot of hardware and software. On the other hand, it also does a lot of research into energy generation, such as fusion, wind, solar, and improvements in combustion-operated power sources such as coal plants and internal combustion engines. There's also work in robotics, biology, chemistry, physics (beyond nuclear explosions!), math, computer science; most of these are not for the development of weapons. It's a DOE lab, so it does things which fall under the DOE mandate, which includes maintaining the nation's nuclear stockpile among many other things.

I think fusion energy is a big enough win for everyone that you don't need to assign some sinister backing to it. The Department of ENERGY damn well should be interested in a safe, clean method of generating electricity.

The logo is a thunderbird, after the mythological creature of the Native Americans.