SEOUL — With the largest South Korea-U.S. spring war drills in six years in full swing, North Korea Friday announced it had successfully tested a new weapons class, a nuclear underwater unmanned vehicle, or UUV, designed to take down targets with a radioactive tidal wave.
The weapon is named “Haeil” —“tsunami” in Korean — according to state media reports, and the test was observed by North Korean leader Kim Jong Un between March 21 and March 23.
The UUV is designed to take out enemy ports or naval formations with the powerful, radioactive waves it generates upon detonation, North Korea stated. The timing of the test, the latest in a string of missile launches since the start of 2022, adds to an already tense time for Washington and Seoul on the divided Korean peninsula, coming just before the arrival of the U.S. aircraft carrier USS Nimitz here next week.
The Haeil, in development since 2012, was named at North Korea’s 2021 Workers’ Party Congress, state media said, the first congress held after President Biden took office.
Former President Donald Trump had thrice met Mr. Kim in an effort to strike a denuclearization deal, but the personal diplomacy broke down and Mr. Biden has not sought to revive it.
Potentially, Haeil raises the threat posed by Mr. Kim’s regime — combining conventional, nuclear, asymmetric and underwater capabilities — to a new high.
“The whole deterrence configuration has been theater missile defense, so is this a blind spot for the U.S. and its allies?” asked Alex Neill, a regional defense expert with the Pacific Forum. “The North Koreans always think creatively.”
While Japan deployed kamikaze speedboats in World War II, and Ukraine has used conventional UUVs against Russian targets in Crimea, no nation to date has used a nuclear UUV in conflict.
“The mission of the underwater strategic nuclear weapon is to stealthily go into the operational waters and destroy the enemy’s warships and major operational ports by creating superpower radioactive tidal waves with [an] underwater explosion,” according to Pyongyang media.
U.S. atomic tests in the Pacific in the 1950s found that such underwater detonations caused major damage to decommissioned aircraft carriers.
As for harbors, “waves generated by an underwater detonation can cause damage in harbors or near the shoreline. … The waves will increase in height as they move into shallower water, and inundation, similar to that observed with tidal waves can occur,” according to the online The Atomic Archive.
The Haeil appears analogous to a Russia-pioneered weapon class being deployed to overcome U.S. ballistic missile defenses. The first of that class, the “Poseidon” nuclear-propelled, nuclear-armed UUV, designed to inundate coastlines with radioactive waves, is reportedly ready to be installed aboard the huge new nuclear submarine Belgorod in July.
Russian state media commentators have made sweeping claims for the Poseidon, contending it is powerful and effective enough to New York.
Ankit Panda, a weapons analyst at the Carnegie Institute, posted images of Mr. Kim on Twitter which showed blurred blueprints in the background. The diagrams resembled Poseidon prototypes, Mr. Panda said, though he believes Haeil is nuclear-armed but not nuclear-propelled.
A source familiar with naval operations said that the lack of a nuclear drive system limited the range and the ability of Haeil to lurk near enemy positions.
While Poseidon launches from a mother vessel, Haeil be can be deployed “at any coast and port or towed by a surface ship for operation,” Pyongyang media said.
The best defense, the naval source said, was a swift strike on its port of deployment early in hostilities. But other analysts say the missile’s automated systems combined with its ability to “loiter” far from port are as worrisome as its firepower.
“These can be deployed, and can loiter, so the launch-to-detonation time can be extended, unlike a torpedo,” said Mr. Neill. “But with an automated system: How do you exercise nuclear command and control over a long period of time?”
The Kim-Kremlin connection
Links between North Korean arms developers and their Russian and Chinese counterparts are opaque. The Biden White House has accused the North of covertly providing shells to the Kremlin for use in Ukraine, but some question whether Russia supplies assets or data in return.
“I am skeptical: I don’t see Russians getting much from supplying such technology to North Koreans,” said Andrei Lankov, a Russian expert on North Korea who teaches at Seoul’s Kookmin University. “They are unreliable operators and if they get a technology, you don’t know how they will use it or transfer it.”
But he also acknowledges that the longer the Ukraine War goes on, the more likely it is that a desperate Kremlin will reach out to any ally that can help.
Others think even if Russia is unwilling to share technology or expertise, that doesn’t mean that coveted technology can’t slip through to Pyongyang.
“Russia is quite vulnerable to cyber attacks and has a huge underground economy, so North Korean hackers could take advantage,” said Go Myong-hyun, a North Korean watcher at Seoul’s Asan Institute. “The second scenario is there could be collaborators in the Russian state.”
Russian and Russian-style equipment is widely used by North Korea, from AK rifles and ballistic missiles to the Soviet-model nuclear research reactor at Yongbyon. Last year, North Korea claimed it tested a hypersonic missile that bore striking similarities to Russia’s Iskander model.
“Russia can see what is going on. They can see these weapons systems being showcased in parades and tested,” Mr. Go said. “But they are making no comments.”
Mr. Panda cautioned about taking Pyongyang’s claims for the new Haeil at face value.
“I tend to take North Korea seriously, but can’t rule out the possibility that this is an attempt at deception/psyop,” he Tweeted. It “would be ill-advised [for North Korea] to allocate limited [fissile materials] for a warhead to go on this thing … vs. more road-mobile ballistic missiles.”
Mr. Lankov differs, saying some features of a new UUV would be easier to manage: “They don’t have to worry about re-entry vehicles, atmospheric pressures and so on. This is easier than ballistic missiles.”
Despite the doubts, North Korea has successfully tested ICBMs capable of hitting the continental U.S. since 2017. It has also test-detonated six nuclear devices, though the extent of its fissile material stockpile remains secret.
And it is skilled in underwater operations. North Korea’s small submarines, operating close to the demilitarized zone separating the two Koreas, have proven credible and deadly threats.
In 1996 and 1998, two reconnaissance submarines infiltrated South Korean waters south of the DMZ along the east coast. Neither was detected, though one ran aground and the other became entangled in fishing nets.
In 2010, a North Korean mini-sub was fingered by Seoul for firing the torpedo that sank South Korea’s corvette Cheonan, killing 46 sailors. Pyongyang denies responsibility. North Korean semi-submersibles have been identified in waters as distant as Jeju Island, 51 miles off the peninsula’s south coast.
Yet, Seoul residents such as Mr. Go, the analyst, are not panicking yet.
“We do not have countermeasures to some North Korean weapons,” he admitted. “But it does not mean they will use them: We have ‘deterrence through retaliation.’”