I would like to point out that there is considerable difference between nuclear “fission” and nuclear “fusion”. To my knowledge nobody in the world had succeeded in creating a sustained fusion reaction outside of a multi-stage thermonuclear weapon, and a “cold fusion” reactor has been the holy grail of nuclear physicists for decades. The chances that NoKo has figured this out are somewhere between slim and none.
This is nonsense coming out of NoKo once again, and if they really had figured out “fusion” their whole country would not be blacked out at night.
This is a pure political ploy, nothing more.
Well, it depends what you mean by sustained. In nuclear time, a half second is a long time, and that is about how long the fusion reaction has run at JET (Europe). This is much longer than a fusion weapon lasts!