Like Bravo, Romeo's explosive power exceeded projections almost tripling the best guess yield. At 11 megatons Romeo was the third largest test ever detonated by the US. The original yield estimate for this test device, known as Runt was only 4 megatons. The reason for this was that it used inexpensive and abundant unenriched natural lithium in the lithium deuteride fusion fuel. In fact as late as October 1953, Los Alamos was considering not even testing this device. The decision to include it was thought to be a crap-shoot to see if this cheap fusion fuel would be useful. Romeo was the first nuclear test conducted on a barge as they were rapidly running out of islands to vapourise.
