| Mark 24 nuclear bomb | |
|---|---|
 A Mk-17 or Mk-24 bomb (casings are identical) | |
| Type | Thermonuclear gravity bomb |
| Place of origin | United States |
| Service history | |
| In service | 1954-1956 |
| Wars | Cold War |
| Production history | |
| Designer | Los Alamos National Laboratory |
| Designed | 1954 |
| Produced | EC-24: Mar-Oct 1954 Mk-24: Jul 1954-Nov 1955 |
| No. built | EC-24: 10 Mk-24: 105 |
| Specifications | |
| Mass | EC-24: 39,600 lb (18,000 kg) Mk-24: 41,400–42,000 lb (18,800–19,100 kg) |
| Length | 24 feet 8 inches (7.52 m) |
| Diameter | 61.4 inches (1.56 m) |
Detonation mechanism | Air burst |
| Blast yield | EC-24: 13.5 megatonnes of TNT (56 PJ), Castle Yankee test Mk-24: 15 megatonnes of TNT (63 PJ) |
The Mark 24 nuclear bomb was an American thermonuclear bomb design, based on the third American thermonuclear bomb test, Castle Yankee. The Mark 24 bomb was tied as the largest weight and size nuclear bomb ever deployed by the United States, with the same size and weight as the Mark 17 nuclear bomb which used a very similar design concept but unenriched lithium.
The Castle Yankee thermonuclear test was the first bomb to use lithium enriched with the lithium-6 isotope, up to perhaps 40% enrichment (the earlier Castle Bravo test had used the same enriched lithium combination but was not weaponised i.e. was not built as a deployable bomb). The device tested was called the Runt II design; it was reportedly very similar to the Runt design tested in Castle Romeo, other than the enrichment level.
Castle Yankee had a demonstrated yield of 13.5 megatons. The yield for the weaponized Mark 24 was predicted to be 10–15 megatons.
The EC24 bomb was a limited production run of the Castle Yankee test device, with 10 produced and stockpiled through 1954. The EC24 was 61 by 255 inches (1.55 by 6.48 m) and weighed 39,600 pounds (18,000 kg). The EC24 was a purely free-fall bomb design.