AHC: Earliest possible atomic weapons?

Goldwater64

Banned
Is it at all possible, with a post-1900 POD, for a significantly (5 years at the least) earlier development and test of an atomic bomb?

Rules:

It needs to be a fission/fusion device. No "dirty bombs".

Pre-1900 PODs allowed if absolutely necessary, but try your hardest to have it after the turn of the century.

Trying to leave this one as free as I can.
 
It'll happen with spontaneous events.

A nuclear experiment gone horribly wrong with a Criticality accident would cause renewed interest in nuclear research for military applications. But not as nuclear weapons as we know it in the beginning.

You just need a scenario where someone gathers nuclear material in one place.
 
There was a novel once called 'Queen Victoria's Bomb' about Victorian technology developing a crude fission device that was delivered by balloon
 
Not before the 20s at least, the technology didn't exist back then to even figure out the difference between the isotopes, that only came with the Mass Spectrometer in 1918.
 
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