The Mark 36 was a more advanced version of the earlier Mark 21 nuclear bomb, which was a weaponized version of the "Shrimp" design, the first "dry" (lithium deuteride) fuel thermonuclear bomb the United States tested, in the Castle Bravo thermonuclear test in 1954 [REF].
The Mark 21 bomb was developed and deployed immediately after Castle Bravo, in 1955.