Buy the Global X Uranium ETF (URA) or simply buy Cameco (CCJ) which is 26% of URA
http://etfdb.com/etf/URA/ has the details
The Van Eck Vectors Nuclear ETF (NLR) gives a play focused more on nuclear energy = energy producers plus a little Cameco plus some equipment makers
Etfdb.com is a great resource. Type any category into the search box to find a lit of ETF's