North Korean Nuclear Test 101 – Introduction to NK’s Nuclear Weapon in Technical Perse

A surveillance satellite found out the cable connecting between underground facility and outside observation equipments in Kilju County in northeast North Korea. The observation equipments have significant meaning since such equipments are usually installed near the site of nuclear test to monitor whether the bomb explodes on time and how much radioactivity is emitted.

Reason for additional nuke tests is to make the nuclear bomb smaller and lighter. The bombs dropped in Japan were heavy (8,800 lbs) and carried by bombers. In the modern warfare, to make more effective nuclear bomb, it must be transported by missile as a form of warhead. And to be so, the nuclear bomb must not be heavier than 2,000 lbs. Once nuclear bomb is developed and tested, another series of tests await for smaller and lighter version of the bomb.

For example, China took five years to develop a nuclear bomb small and light enough to be carried by a missile, and twenty years to create one for actual use, since its first nuclear test in 1964.

Why Nuclear Test 3- To Check Safety Device

Every parachute is equipped with a safety device, which prevents releasing the parachute too easily and is not too strict so that the parachute does open on time.

Nuclear bomb has safety device of similar role. Several layers of safety device avoid a nuke exploding in a shelter. And the device is tested many times to make sure the nuclear bomb blow up at desired moment.

Moreover, Plutonium, although a half-life of which is 24,000 years, is extremely delicate to small change of mass, and therefore, outdated Plutonium bombs need to be tested, periodically.

Why Nuclear Test 4- Political Reason

To simply put, countries feel not intimidating enough by merely declaring possession of nuke bombs. So they show off their nuclear power. Although the test is not broadcasted, other countries can detect success or failure of the test and the capacity of nuclear bomb through seismic waves produced by explosion and atmospheric radioactivity.

And exposure of nuke can be used to bully other countries. During the Cold War, five conventional nuclear states, under the principle of Mutual Assured Destruction, competed over development of nuclear weapons to threaten their enemy.

Nuclear tests can also play a role in strengthening the national unity. Especially for the countries of authoritarian rule and in conflict with their neighbors, nuclear tests stimulate people’s antagonism against the enemy and loyalty to the regime.

Most obvious cases are India and Pakistan. India initiated the nuclear race in South Asia not only because decades-long threat from China and Pakistan but also because newly elected BJP government’s effort to gain popular support. At that time, in 1998, India was not in serious conflict with either China or Pakistan. Yet, when the New Delhi government tested its nuclear weapon, residents near the test site cheered rather than demonstrated against danger of radioactivity.

Pakistan responded in two weeks by testing its own nuclear bomb. Pakistani people urged their government so intensely that if the government did not conduct the test, Prime Minister Nawaz Sharif’s political fortune would have been doomed.

India tested its nuclear bomb five times total in 1998, 3 times on May 11th and twice on May 13th. Pakistan did six times, five times on May 28th and once on May 30th, with the purpose of winning its rival in the number of nuclear testing.

Types of Nuclear Test and Its Effect

Nuclear test is conducted on ground, underground and underwater. On ground nuclear tests are typical between the US and Soviet Union during their early days of nuclear race. However, due to radioactive material emitted by on ground nuclear test contaminating the atmosphere of contiguous area, the US and Soviet Union agreed not to carry out additional on ground test in 1963. France and China did not sign the agreement and kept testing their nuclear weapon on ground.

Underwater nuclear testing is usually done in international waters, and pollute oceanic ecosystem. Because of France’s nuclear tests near the Polynesian Islands for more than 100 times, the ocean near the area is now in unrecoverable condition.

Underground nuclear test is preferable compared to the other two types of testing since the former does not damage neighboring countries and can be done relatively quietly. Underground testing, however, might cause artificial earthquake and even eruption of nuclear material if the magnitude of explosion is miscalculated.

There is little chance of testing nuclear bomb on ground or underwater by North Korea because of the inevitability of contaminating the North’s neighbors. Thus the only alternative is underground nuclear test.

Nuclear states have conducted underground nuclear tests in desert. In North Korea, however, there is no desert, so it is expected that a nuclear test, if done, would be carried out in mountainous area far from populated region.

How to do underground test

Underground nuclear test is simple; first, drill the ground deep enough for safe test, then insert nuclear bomb at the bottom, and detonate the bomb from outside. As tunnel collapses, the entrance is closed and radioactive material is sealed.

1st phase

Tunnel is drilled with a depth of 200 to 1000 meters, dependent on the strength of nuclear bomb. 200-meter is enough for a nuclear bomb with magnitude of tens of kiloton. Megaton-strong hydrogen bomb needs a tunnel longer than 1 kilometer. Tunnel’s width is about 1 to 3 meter, and inside the tunnel layers of cement, plaster and steel cover the wall. An observatory is constructed 200 meters from the site to check the result of nuclear test.

2nd phase

After preparation is completed, nuclear bomb is moved to the tunnel. The bomb is put into a sealed container and located on the bottom of tunnel. To make sure safety, a truck with huge container carries the bomb.

And a fiber-optic cable is set to connect between the nuclear bomb and on-ground observatory. Around nuclear bomb, camera and radioactivity measuring instrument are stationed. Satellites can observe those movements.

3rd phase

As everything is set, entrance of the tunnel is sealed by cement and rocks to prevent radioactive material leaking out to the ground after explosion. Sealing of tunnel is the most obvious sign of forthcoming nuclear test.

After these three phases, only pressing the button is left. Nuclear test lasts no more than two hours. As the button is pushed, within one millionth of second, explosion occurs. And as soon as all the observed data are collected and transferred to the main observatory in one millionth second, instruments are all melted.

And everything else, including cements and iron plate, around the bomb is melted, too, and the entrance is sealed by the melted magma. Radioactive material is locked in the tunnel.

Right after the explosion, a seismic wave, which is detectable from hundreds of miles far from the site, occurs.

Test is completed when magma and gas are collected after a few hours of explosion. And capability of nuclear weapon can be measured.

North Korea already conducted nuclear test?

As mentioned above, Plutonium bomb necessarily needs to be tested. But there is an indirect way to test Plutonium bomb by hitchhiking.

South Africa once possessed its own nuclear weapon and abandoned it, later. In 1979, South Africa tested 2-4 kiloton small nuclear bomb and had produced total of 6 bombs until 1989, although the bombs were only transportable by airplane.

There are testimonies that South Africa’s 1979 nuke test was a joint-venture with Israel. Uranium rich South Africa lacked nuclear bomb technology, and the country exchanged Uranium with Israeli technology. Thus, Israel is suspected having virtually done its nuclear test in South Africa. South Africa decided to abandon nuclear weapon in 1989 and received 120 times of IAEA inspection until 1993. IAEA declared South Africa’s nuclear program was over.

Similarly, North Korea is allegedly involved in Pakistan’s nuclear weapon development. Some suppose that the Pakistanis bartered their weapon technology with North Korea’s missile. In May 1998 during Pakistan’s nuclear testing, it is known that 20 to 30 North Korean scientists came to Pakistan and watched the test. Hwang Jang Yop, former North Korea’s KWP foreign secretary who defected to South Korea, said that North Korea practically did nuclear test together with Pakistan.

Several scholars and intelligence officials argue that Pakistan’s second nuclear test on May 30, 1998 is actually North Korea’s. In fact, Pakistan’s second nuclear test is suspicious. During its first nuke test, Pakistan tested five times and during the second test, it only did test once.

In average nuclear test, to avoid failure and compare various types of bombs, two or three tests are conducted. For example, India tested three bombs in its first nuclear test and two bombs in the second one. However, Pakistan consumed five bombs at first and then another one, separately. Why?

Moreover, first and second nuclear test sites were different, and, while the first nuke test was done publicly, the second test was carried out relatively quietly. Therefore it is suspected that the bomb tested on May 30, 1998 is actually North Korean made one and Pakistan merely provided place. Those who believe in such suspicion argue that North Korea is only pretending to do nuclear test.

Even though it is possible to use somebody else’s land to test a nuclear bomb, to upgrade the bomb’s performance, an open test is inevitable, someday.

How many bombs in North Korea

It varies among scholars and institutions to estimate how much Plutonium North Korea possesses. Most reliable one is about 60 kg, or 132 lbs. According to the estimate, North Korea reprocessed 30 kg during the first nuclear crisis in 1992-93. And another 30 was extracted right after the second crisis broke out. If North Korea started reprocessing from last year, then another 30 kg might be included, in addition to the 60 kg.

Out of 60 kg of Plutonium, 6 to 7 bombs could be made. And it corresponds to IAEA’s estimate. And since every nuclear test requires two or three bombs, North Korea might do test twice; the second test, of course, is not necessary if the first is successful.

Technical side of nuclear test

Many people point out nuclear test’s political aspect. Their argument is that Pyongyang would not test its nuclear bomb because the test would deteriorate its relationship with Beijing. Although the argument does make complete sense, another aspect of nuclear test, which is technical one, must not be overlooked.

Nuclear bomb is developed with a huge amount of time and money, and it is not developed to be kept carefully in garage. There are plenty of technical reasons to actually test the bomb’s performance and improve it.