I'm pessimistic, especially since the article suggests that Bussard's scaling rule isn't proven. The should have been demonstrable by using different power levels on the same reactor and seeing how the radiation levels change. The group doing the research wants to build a bigger functional reactor to test it. My take is that they don't have to do that. But I guess a thing isn't proven until it's proven. And why not spend a few $million to prove it. At least it's not few $billion. And indeed, if the small reactor doesn't turn up any showstoppers, and the next step is a bigger functional reactor, well then do it already.