in a 2010 ted talk, he announced he had co-founded a company called terrapower. partner is his former chief technology officer at microsoft, nathan myhrvold. >> we need to have base load carbon-free power, and nuclear is a great example of something that is base load carbon-free power. base load means 7 by 24, day and night, whenever, it's going to be there. >> reporter: terrapower's reactor uses a design that dates back to the first ever nuclear power plant, built here in idaho. it illuminated its first light bulbs in 1951. it's an entirely different design than the vast majority of nuclear reactors currently operating. the fuel was not cooled with water, but rather liquid metal-- sodium mixed with potassium-- which has a lower melting point, absorbs more heat, and has a much higher boiling point than water. it had some inherent safety advantages over water-cooled reactors, which cannot safely shut down without electricity from the grid to keep cooling pumps running. this is what happened at fukushima in 2011; an earthquake and tsunami caused a station blackout