Little Boy was a simple U-235 "gun-type" design, Fat Man a Pu-239 hollow-pit implosion, but without any booster.
Modern warheads are all Pu-239, and it is believed all nuclear powers, even the minor ones, have mastered boosting - a few grams of tritium and deuterium gas inside the hollow pit, that fuses under the pressure generated by the initial burst of fission, yielding a small number of 14 MeV "hard" fusion neutrons to catalyse further fission.
Only a few powers (US, France, Britain, Russia, China and India) have gone on to develop "true" three-stage H-bombs, using lithium deuteride secondaries "downstream" of the primary pit.
(None of that is classified, I never held a clearance high enough to see the details!)
Low Information Voter
npub149…tzmp0
2025-06-02 12:43:20 UTC
in reply to nevent1q…f8re
Author Public Key
npub1494rtg3ygq4cqawymgs0q3mcj6hucvu4kmadv03s5ey2sg32df5shtzmp0Published at
2025-06-02 12:43:20 UTCEvent JSON
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"content": "Little Boy was a simple U-235 \"gun-type\" design, Fat Man a Pu-239 hollow-pit implosion, but without any booster.\n\nModern warheads are all Pu-239, and it is believed all nuclear powers, even the minor ones, have mastered boosting - a few grams of tritium and deuterium gas inside the hollow pit, that fuses under the pressure generated by the initial burst of fission, yielding a small number of 14 MeV \"hard\" fusion neutrons to catalyse further fission.\n\nOnly a few powers (US, France, Britain, Russia, China and India) have gone on to develop \"true\" three-stage H-bombs, using lithium deuteride secondaries \"downstream\" of the primary pit.\n\n(None of that is classified, I never held a clearance high enough to see the details!)",
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