06/01/2016 8:13 PM AEDT | Updated 15/07/2016 12:51 PM AEST

South Korea's Official Line About North Korea: 'Boosted Fission Weapon More Likely Than Hydrogen Bomb'

People watch a TV news program showing North Korea's announcement, at the Seoul Railway Station in Seoul, South Korea, Wednesday, Jan. 6, 2016. North Korea said Wednesday it had conducted a hydrogen bomb test, a defiant and surprising move that, if confirmed, would put Pyongyang a big step closer toward improving its still-limited nuclear arsenal. The letters read

Today, North Korea made international headlines when it announced it "had succeeded in testing a hydrogen bomb," but South Korean officials are suggesting that there might be something more to that story.

According to Yonhap News,"the [South Korean] government is leaning more toward a test of boosted fission weapon which is a form of bomb one level away from a hydrogen bomb."

"It's a weapon that incorporates deuterium, tritium or lithium-6 in order to increase the fission in the nuclear device and is one step away from a real hydrogen bomb. It is two to five times more powerful than a normal atom bomb. Also, as it does not require a minimum mass, or the critical mass, for the nuclear fission, it can be miniaturized which is a considerable advantage. Thanks also to the use of uranium-238, hydrogen and lithium, there's suppose to be no nuclear fallout."

The possibility that North Korea might test a boosted fission device was previously hinted at in March 2014 when North Korea mentioned that it was gearing up for a fourth nuclear test. At the time North Korea's Foreign Ministry official let it be known that the next test would be "a totally different type of nuclear bomb test."

Science Times reported back in April 2014 that "with the possibility of North Korea developing a dangerous nuclear weapon that goes beyond the long-range missiles with high capacity nuclear warhead, experts concur that the key is the 'miniaturization of nuclear warheads used on mid-to-long-range missiles.'"

SBS TV news cited an official from the South Korean military who said they were "watching and analyzing North Korea's claim that it had proven scientifically that the technical data on the power of the miniaturized test hydrogen bomb was correct."

"Seeing how they used the words 'test hydrogen bomb' and 'miniaturized hydrogen bomb', it seems likely that this was a test step on the way to developing a full-scale hydrogen bomb."  

The reason there are suggestions that it was a boosted fission bomb rather than a hydrogen bomb is because an actual hydrogen bomb testing is considered acutely dangerous. Yonhap News reported that "countries with nuclear weapons, considering hydrogen bomb testing to be highly dangerous, have eschewed inland for the ocean or the desert." The latest explosion, however, was detected inland around North Korea's HamGyeongBukDo province's GilJu, PoonGyeri, and as such, it suggests that it was something that would be no huge trouble to explode on land, so probably not hydrogen bomb.