Containment is Paramount
Japan is highly vulnerable to airborne radioactive fallout from a nuclear incident on the Korean Peninsula, given prevailing westerly winds. On an increasingly regular basis, Japan endures unhealthy waves of air pollution emanating from China via Korea, in the form of so-called yellow dust, yellow sand, or other fine particulate matter (PM 2.5). The situation is worst in winter fueled by increased coal use and stronger seasonal winds. Once the pollutants are airborne, there is little the Japanese government can do but alert the public to take basic precautions, such as wearing face mask or limiting outdoor exposure. Radioactive material, however, would create an unmanageable health crisis.
A 2017 study by the Natural Resources Defense Council estimated that a nuclear accident in Busan South Korea—in this case a loss of cooling water leading to a fuel storage explosion—would force the Japanese government to evacuate more than 28 million people in Western Japan to avoid the severe health risks from breathing air contaminated by cesium-137 or other radioactive micro-particles. A similar accident at Yongbyon in North Korea would probably be smaller in scale (given the smaller size facility) but could still affect millions, as the more densely populated Kanto region in Japan (including Tokyo, Kawasaki, Yokohama, and Chiba) is likely to be in the path of fallout from the DPRK.
For comparison, the costly and logistically challenging evacuation in Japan caused by the Tokushima nuclear crisis in 2010 involved about 300,000 local residents. All of the U.S. bombing in Japan late in World War II forced evacuations of about nine million Japanese, requiring complete national mobilization. To relocate 28 million is frankly unfathomable, not to mention the long-term economic toll this would take on the nation and the entire region. Japan’s paramount interest, therefore, is doing whatever it can to help contain the local nuclear accident and prevent a worst-case scenario.
Information and Assistance are Priorities
Upon news of the accident, Japan’s National Security Council would convene an emergency meeting and stand up an interagency task force, led by the Deputy Chief Cabinet Secretary for Crisis Management. Initial priorities include assessing the situation, preparing for possible invocation of the Civil Protection Law to authorize emergency powers for possible evacuations (in Japan and/or Japanese residents in South Korea), and mobilizing certain equipment that could aid in a North Korea or multilateral response to the crisis. Mitigation would be much easier if North Korea allows for direct international assistance, perhaps under a UN umbrella with a team involving people experienced with disaster relief in North Korea and veterans of IAEA monitoring activities at Yongbyon in the early 2000s.
For example, Japan can make available equipment for aerial analysis and assessment of ground deposition of radioactive materials (utilizing specially configured helicopters and an unmanned reconnaissance plane received from the Americans in 2010). Japan could also provide water pump trucks, radiation suits, robotic cameras for surveillance, decontamination facilities, and other material necessary for addressing potential nuclear risks.
The Japanese government would kick into high gear diplomatically, working bilaterally with the United States, the Republic of Korea, China, and Russia, looking to share information (including satellite imagery when feasible) and developing a coordinated response. Coordinating with Washington would be relatively easy, given their close alliance and the experience working together in 2010 involving the military, diplomats, and nuclear authorities of both countries. Tokyo would likely be uniquely forthcoming with Seoul sharing information, testing the limits of their military intelligence sharing agreement of 2016. All three of these countries were critical players in the international response to a deadly Ebola virus outbreak in Africa in 2014-15, acting directly and through the UN system to provide hundreds of millions of dollars, medicine, in-kind contributions, and medical and logistics professionals to help contain the threat. A similar approach would be sought in this case.
As for Japan’s diplomatic objective, its preference would be for at least a small international investigative team on the ground at Yongbyon as quickly as possible, ideally with some Japanese representation, but Tokyo would probably not insist on this point if North Korea balked. A key question is what to do if North Korea refuses international assistance of any kind, while indications become clearer that a potentially catastrophic nuclear accident is occurring.
It is hard to see how the allies could impose their will upon North Korea, so all efforts would be made to convince Pyongyang to accept some outside help voluntarily. This could include turning to different channels of communication, such as Chosen Soren (or the General Association of Korean Residents in Japan), which is a political group of ethnic Koreans in Japan who remain loyal to North Korea. Perhaps they could be persuasive for the sake of protecting their own members. Japan would go to great lengths to demonstrate benevolent intent toward North Korea in this particular instance, being more flexible with regard to spending money and providing assistance than is normally the case, even if it applies only to this situation.
As this crisis is unfolding, economic markets would be weakening, requiring government efforts to backstop Japanese firms and ameliorate volatility. Soon after Japan’s nuclear crisis became evident in 2010, the nation’s stock indices suffered their worst two-day selloff—down about 17 percent—since 1987. South Korean, Chinese, and U.S. markets would be hurting as well. Beyond jittery markets, if radioactive fallout did begin to affect Japan and trigger mandatory evacuations in certain areas, it could affect supply chain management that can send ripples throughout the region. This also happened in 2010, affecting various industries including autos, semiconductors, and electronics. Thus, another priority for Tokyo would be to mobilize manufacturers to mitigate the potential impact of a worst-case scenario even as it pledges reassuring support for firms, banks, and insurance companies to discourage panic selling. The economic dimension of this challenge involves both logistics and psychology.
The Japanese government is experienced at trying to manage natural disasters (home and abroad), financial crises, and also nuclear accidents, even if its performance is mixed given the enormous challenges involved. The emotional scar of the Tokushima nuclear crisis in Japan is still so fresh that a similar crisis in North Korea would consume the public and the authorities. They would drop everything to help contain the fallout and work with whomever necessary in the region and around the world to address the threat. Japan has technical expertise and financial resources to offer, and it will leverage all of its multilateral and bilateral relationships to deliver what it can.
Underlying distrust of North Korean leadership, the outstanding issue of missing Japanese abducted by North Korea in the past, and the increasing nuclear and missile threats mean that Japanese flexibility and generosity would likely end once the nuclear safety issue is under control, but the experience might open a door to bilateral or multilateral cooperation with North Korea even after the incident is contained, if nuclear safety can be improved without extortion efforts by Pyongyang.