SLIDE 1 BRAVO Cloud Dimensions. The BRAVO device was detonated on a sandspit near Namu Island, Bikini Atoll at 0645 March 1, 1954 (28/2/54 1845 GCT). It was a 17 MT thermonuclear yield. The upper limit to cloud height was 40 km (25 miles). The diameter 10 minutes after the burst was 110 km (70 miles). The fission/fusion ratio was estimated to be 0.47. series of experiments. later. It was the first in the Castle The second shot was 100 KT and occurred 30 days The next three shots were 150 RT, 9.5 MT and 10 MT respectively. The 9.5 and 10 MT shots may have contributed some fallout at Rongelap and Utirik, perhaps as much as a 8% of the surface activity. These later shots occurred after persons were evacuated. 7 TTT 7 T i t T Cioud Heignt Lower Limit Cloud Tep Heigm * ngooot t e 3 s to ! | ! iz ) 3 r | a of ; z ‘oad ‘ Sb 3 sor 3 ‘ ‘ I ‘ i ; ° 7 1 4 | 3 171,400 91. 47 |_| | ‘ { Stem Drameter | i | ‘ ju | }og + ¢ 60 = 4 § E 6 3 4 eo 2 —_ - LY | | 4 ' ~ i % “ 23,400 ff pa ok | I { 20 : Srameter } r 200 @ I 38,3011 7 soo 4 Ciovd Bottom Height L ‘ —“ / fF -_ 7 280 Poy ae e Vv / XI Fr et ~ 100 wo 4 380 at an ph or or } = 1 4 80 7 JO Time, Minules Cloud Dimensions: Operation CASTLE - Shot 1 - Bravo.