Operation Castle was considered by government officials to be a success as it proved the feasibility of deployable " dry " fuel designs for thermonuclear weapons . There were technical difficulties with some of the tests : one device had a yield much lower than predicted ( a " fizzle " ) , while two other bombs detonated with over twice their predicted yields . One test in particular , '' Castle Bravo '' , resulted in extensive radiological contamination . The fallout affected nearby islands including inhabitants and U.S. soldiers stationed there , as well as a nearby Japanese fishing boat ( the '' Daigo Fukuryū Maru '' ) , resulting in one direct fatality , and then continued health problems for many of those exposed . Public reaction to the tests and an awareness of the long-range effects of nuclear fallout has been attributed as being part of the motivation for the Partial Test Ban Treaty of 1963
Castle Bravo
Castle Bravo
Operation Castle