As for the 100-megaton nuclear devices, head Soviet nuclear physicist and later dissident Andrei Sakharov had a plan to achieve that kind of yield. Sakharov’s team would use “clustering and ...

Soviet scientists arrived at a 50-megaton yield but for decades their nation was happy to accept the higher American figure. And yet it could have been even more powerful—a full 100 megatons.

Andrei Sakharov, a Soviet physicist, conceived of the 100-megaton weapon. He ultimately reduced its yield to a lower (though still devastating) 50 megatons. Even with the reduced yield ...