North Korea probably can make nuclear warheads that are small enough to fit on its ballistic missiles, and activities at its nuclear test site and satellite launch facility likely indicate that Pyongyang is planning further tests to continue improving its nuclear arsenal, a former South Korean official said last month.
In a May 19 interview, the former official said that Pyongyang can “likely fit a nuclear warhead on a Rodong missile” although it is not certain that the warhead would detonate properly.
The medium-range Rodong missile, also known as the Nodong, is a deployed system with a range of 1,300 kilometers. This places South Korea, Japan, and parts of China within its range.
Experts have expressed skepticism in the past about North Korea’s ability to deliver a nuclear warhead via a missile, but that sentiment apparently is beginning to shift.
The former official said his opinion was based on recent North Korean statements and actions, including a February 2013 nuclear test and two Nodong missile tests in March.
But he cautioned against the assumption that North Korea has deliverable nuclear warheads.
When delivered via ballistic missile, nuclear warheads must survive re-entry into the atmosphere, a process that is difficult to perfect even with “advanced resources and technology,” which North Korea does not have, the official said.
One of the key difficulties in delivering a nuclear warhead via a missile is making it small enough to fit. The process of making a nuclear device compact enough for delivery is often referred to as miniaturization.
North Korea conducted nuclear tests in October 2006, May 2009, and February 2013. (See ACT, March 2013.) After the 2013 test, North Korea said the device was “smaller and lighter” than past devices. Partly on the basis of that statement, some experts thought that the 2013 test might have used a miniaturized warhead. No public evidence of such a capability has emerged since then.
According to a U.S. intelligence assessment released in January, Pyongyang’s “employment concepts”—the ways in which it would use nuclear weapons—are unknown.
Pyongyang is thought to have four to 10 nuclear weapons that are plutonium based. Last year, it restarted a reactor that produces plutonium that could be separated for additional weapons. (See ACT, October 2013.) North Korea also possesses uranium-enrichment technology, giving it another potential route to making nuclear weapons, but it is unclear how much highly enriched uranium, if any, it has produced.
According to experts, satellite imagery of the Yongbyon nuclear test site shows continued activity indicative of preparations for another test. North Korea announced in March that it is considering a “new form” of nuclear test, but did not give specifics as to the meaning of that term or the timing of the test. (See ACT, May 2014.)
In an May 13 article posted on 38 North, a website run by the U.S.-Korea Institute at Johns Hopkins University, Nick Hansen and Jack Liu wrote that activities at the Punggye-ri test facility indicate that a fourth nuclear test is not imminent, despite speculation to the contrary.
According to Hansen and Liu’s analysis of satellite imagery, activity in the West Portal area of the site shows continued excavation of a test tunnel. Workers also appear to be widening a road leading to the tunnel portal, Hansen and Liu said. If a test were imminent, North Korea would need to seal the tunnel.
The two analysts wrote that if a test was imminent, there would be a “high level of activity” in the site’s Main Support Area, which has a key role in preparing for a nuclear test. The current activities “seem consistent with those needed for routine maintenance,” Hansen and Liu said.
They also said activity is evident at the Sohae Satellite Launching Station in northwest North Korea.
In a May 20 piece, the analysts wrote that recent satellite images show construction projects at the Sohae site that could be intended for mobile launches of intercontinental ballistic missiles (ICBM). They concluded that it is “too soon to make a definitive judgment” on the purpose of these projects, but noted several developments consistent with the hypothesis that North Korea is planning to test ICBMs at the site.
North Korea has displayed mock-ups of an ICBM known as the KN-08, or Hwasong-13, in several military parades dating back to April 2012.
According to Hansen and Liu, construction of a “circular facility with a diameter of 50 meters” could be a launch pad for a mobile missile such as the KN-08. The presence of a new reinforced concrete road connecting the possible launch pad to the missile assembly building at the site supports the hypothesis that North Korea is building a mobile launch pad for ICBM tests, they said.
The analysts said that this hypothesis is also supported by evidence of “ongoing KN-08 engine tests” at the Sohae facility.
The January U.S. intelligence report said that North Korea has “already taken initial steps” toward fielding the KN-08 but it remains untested.