Correction: This article originally had Jeffrey Lewis’s affiliation as the Monterey Institute for International Studeis, the previous name for the
North Korea claimed to have conduced a successful test of a hydrogen bomb (H-bomb) on Wednesday morning. Experts expressed mixed opinions, indicating that North Korea may have anything from a real H-bomb to the stage before it in development.
“The H bomb test is the higher stage of our nuclear development power. Through the most successful test of the H bomb, DPRK has proudly become one of the nuclear power states,” the official statement broadcast on the North’s state-run Korean Central Television (KCTV) on the same day reads.
The term “H-bomb” or hydrogen bomb refers to thermonuclear device which relies on hydrogen fusion to fuel a nuclear reaction and boost the explosive yield of the weapon. A proper thermonuclear device features separate stages of nuclear fission and fusion reactions while less complex versions – the phases of development before a true H-bomb – merely feature boosted fission.
Seoul’s National Intelligence Service reported to lawmakers that it might not be an H-bomb, considering the force and the seismic wave.
“The power of third nuclear test was 7.9 kilotons, but this time was 6.0 kiloton. The seismic wave of the third test was 4.9, while it is 4.8 this time,” Lee Choel-woo, a ruling Saenuri party’s lawmaker told journalists, delivering the NIS’s report, in remarks carried by local media.
One technology expert was skeptical on North Korea’s possession of H-bomb.
“It seems like North Korea has obtained a reinforced (boosted fission) nuclear bomb, which is in the middle of developing an H-bomb. The countries which have atomic bombs try to achieve reinforced bombs, but it is difficult to ensure the materials to make it.” Lee Chun-geun, a researcher at Science and Technology Policy Institute, told NK News.
An H-bomb works by fusing the light nuclear elements, while the atomic bomb works by nuclear fusion of heavy elements.
Jeffrey Lewis, director of the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies at the, expressed similar skepticism that North Korea has developed a true hydrogen bomb and believes it is likely a reinforced bomb.
“A lot depends on the size of the event,” Lewis told NK News. “If the event was on the large size, say a few tens of tons, then it might have been boosted or used some fusion fuel.”
“I think we can, however, rule out a staged thermonuclear weapon,” Lewis continued. “It is much too small for that.”
“A reinforced bomb is the mixture of them, based on the fission which adds hydrogen. This is the 1.5 generation of the nuclear bomb,” Kim Tae-woo, former president of the Korea Institution of National Unification, told NK News.
The reinforced bomb can be miniaturized, with increased explosive power, which is advantageous as a warhead.
Kim agreed that North Korea may have exaggerated its capacity and technology, but there is no reason not to believe North Korea’s statement.
“North Korea has never ceased nuclear development, as well as the missiles or submarines to carry (the devices). For the Soviets and China, it took only five years to create the H-bomb from the atomic bomb,” Kim said.
Another expert echoed this argument.
“Looking back at the past instances, the U.S., Russia, U.K., France and China all successfully conducted hydrogen bomb tests about three to five years after their nuclear bomb test. As North Korea conducted their first successful nuclear test in 2006, the country had at least 10 years of time for development, which is double than most of the previous countries,” Eom Sang-yoon, a nuclear weapon researcher from Sejong Institute, told NK News.
Additional reporting: JH Ahn and John G. Grisafi