Producing even a little heat with fusion produces a lot of nasty radiation.  As in kill everyone in the unsheilded room within a few seconds.<p>Based on the amount of unexplained heat they produced fusion would have been extremely radioactive, however they did not treat there setup as an extreme radiation hazard.  Which suggest they did not think there would be any fusion.<p>PS: Here are some pictures for a device expected to produce less than 1W of fusion. <a href="http:&#x2F;&#x2F;www.cmgww.com&#x2F;historic&#x2F;farnsworth&#x2F;inventions&#x2F;fusion&#x2F;fusionhot.html" rel="nofollow">http:&#x2F;&#x2F;www.cmgww.com&#x2F;historic&#x2F;farnsworth&#x2F;inventions&#x2F;fusion&#x2F;f...</a>  Note the deep and cheap to produce pit.