Image copyright AP
North Korea has conducted 4 underground nuclear assessments so far.
Each one has taken it in the direction of what a long time of international talks have attempted to prevent – a nuclear weapon in the hands of 1 of the world’s most unpredictable states.
The four exams
9 October 2006 – a weapon for ‘peace’
Years of posturing – and attempts at negotiation by means of overseas powers – culminated in October 2006 with an announcement through Pyongyang that it had carried out its first nuclear explosion.
Like all assessments that would observe, it happened underground, in tunnels dug into a faraway mountainous web page referred to as Punggye-ri, within the north-east.
Image copyright Reuters Image caption All of the tests were performed underground at the Punggye-ni website online in the north-east
The software is assumed to have used plutonium, sourced from the North’s nuclear facility at Yongbyon.
International observers envisioned the blast had an energy discharge of a few kiloton, lower than a tenth of the dimensions of the bomb dropped on Hiroshima in 1945.
Many believed this indicated a nuclear “fizzle” rather than a completely efficient blast.
but the North said it had joined the nuclear membership and that its bomb would contribute to peace and balance on the Korean peninsula.
25 Might 2009 – attempt to end up balance
The Second take a look at was once larger, with an anticipated yield of two-EIGHT kilotons.
North Korea stated it had achieved a “upper level in phrases of its explosive energy and era”.
Image copyright AFP Image caption The Second test, right here applauded through Celebration officers, was seen as an strive by way of the North to prove it would nonetheless conduct a take a look at regardless of political uncertainty 
Image copyright AFP Symbol caption The nuclear tests are to begin with detected by way of the seismic waves they generate
At The Same Time As the international consensus was that a nuclear take a look at had happened, no radiation used to be detected. the facility to include a nuclear test might in itself be a big strengthen for the North.
It additionally followed arduous at the heels of a take a look at of a missile with an extended enough vary to reach the united states.
Both had been observed as an strive by sick chief Kim Jong-il to end up the North’s nuclear capacity sooner than he died.
12 February 2013 – uranium-enrichment?
within the early hours of 12 February 2013, ordinary seismic process was again detected around Punggye-ri.
The North mentioned it had examined “a miniaturised and lighter nuclear tool with larger explosive pressure than up to now”.
Image copyright Geoeye Symbol caption Satellite Tv For Pc pictures in days prior to the blast had indicated a take a look at was once about to happen
The as-but unproven connection with “miniaturised” stoked fears that Pyongyang used to be in the direction of generating a device small enough to fit on a protracted-range missile.
Hypothesis used to be rife that the take a look at concerned a uranium device, regardless that this hasn’t ever been confirmed beyond doubt.
A successful uranium test may mark a significant step forward in North Korea’s nuclear programme. The North’s plutonium stocks are finite, but when it might enrich uranium it might building up a nuclear stockpile.
Plutonium enrichment additionally has to happen in huge, simple-to-spot facilities, while uranium enrichment can extra easily be performed in secrecy.
6 January 2016 – thermonuclear claim
The first indication used to be once more file of an “synthetic quake” in North Korea, registering about magnitude 5.1, close to Punggye-ri.
North Korea later introduced it had performed its first a hit take a look at of a hydrogen bomb.
H-bombs, also referred to as thermonuclear warheads, are massively more robust than atomic bombs, the use of fusion – the merging of atoms – in preference to fission to unharness monumental amounts of energy.
Though once more it has never been showed, that declare alarmed the global community.
Observations from afar steered the blast detected used to be now not sufficiently big to had been a full thermonuclear tool, however can have concerned a few nuclear fusion.
Again, North Korea mentioned the tool have been miniaturised.
9 March 2016 – a deliverable instrument?
a couple of months later, Kim Jong-un announced that North Korea scientists have been able to do what had lengthy been feared, and make a nuclear warhead small enough to fit on a warhead.
Symbol copyright Rodong Sinmun Image caption North Korea’s state media confirmed an image of Kim Jong-Un analyzing the purported nuclear warhead
It got here after days of threats to hold out “indiscriminate” assaults on the US and South Korea. However analysts stated it was inconceivable to confirm.
