Science, Technology, and Public Policy

Some experts are increasingly concerned that China’s modernization will lead to a Chinese nuclear “breakout”—a pursuit of a nuclear-warfighting capability or a “sprint to parity” with the United States. David Logan (“Hard Constraints on a Chinese Nuclear Breakout,” Vol. 24, Nos. 1–2, 2017, pp. 13–30) rightly suggests that such a nuclear breakout would be constrained not only by China’s “soft” nuclear policy but also by “hard” technical constraints. I would emphasize that it is the former that has been the first principle guiding China’s nuclear-force development. That some of the “hard” technical constrains have resulted from this “soft” guidance demonstrates China’s commitment to a small deterrent force. It is difficult to imagine that the future development of China’s nuclear force would eventually overthrow these first principles. In fact, there is no evidence that China will change its long-standing nuclear policy.

Effective verification will be absolutely essential to achieving nuclear disarmament. Developing effective verification may seem an impossible challenge, but there is substantial experience to build on, including IAEA safeguards and bilateral arms control processes. Examining the specific steps required to progress disarmament, we are not starting with a blank sheet, many verification missions are similar to those existing or under development today. International collaboration in developing new verification applications will contribute to the confidence and trust required to achieve the elimination of nuclear weapons.

China began producing highly enriched uranium (HEU) and plutonium for nuclear weapons in the 1960s and is believed to have halted production the 1980s. Despite the passage of thirty years there has been no official policy declaration in this regard. This report uses newly available public information from Chinese sources to provide an improved reconstruction of the history of China’s production of HEU and plutonium for nuclear weapons. This allows improved estimates of the amount of HEU and plutonium China has produced and of its current stockpiles.

If we had the technology to detect nuclear materials remotely it could help deter smuggling and make it easier to monitor international nuclear agreements. Several recent breakthroughs, if followed up with continued research and funding, could deliver on this promise. They include technological advances in x-ray and neutron radiography; a method that measures how plasma breaks down when exposed to a radioactive source; and developments in antineutrino detection. While all require more development and testing, they are important steps as the global need for ways to detect nuclear materials grows.

Last week, President Trump signed a new executive order that paves the way to impose sanctions against any foreign bank that conducts business with North Korea, going well beyond current UN financial sanctions. These so-called secondary sanctions, which are penalties applied to third-party foreign banks (i.e., not directly against North Korean entities), are particularly focused on Chinese banks.

The escalating threats between North Korea and the United States make it easy to forget the “nuclear nightmare,” as former US Secretary of Defense William J. Perry put it, that could result even from the use of just a single terrorist nuclear bomb in the heart of a major city.

At the risk of repeating the vast literature on the tragedies of Hiroshima and Nagasaki—and the substantial literature surrounding nuclear tests and simulations since then—we attempt to spell out here the likely consequences of the explosion of a single terrorist nuclear bomb on a major city, and its subsequent ripple effects on the rest of the planet. Depending on where and when it was detonated, the blast, fire, initial radiation, and long-term radioactive fallout from such a bomb could leave the heart of a major city a smoldering radioactive ruin, killing tens or hundreds of thousands of people and wounding hundreds of thousands more. Vast areas would have to be evacuated and might be uninhabitable for years. Economic, political, and social aftershocks would ripple throughout the world. A single terrorist nuclear bomb would change history. The country attacked—and the world—would never be the same.

America’s top priority must be to avoid a second Korean war. Yet such a war is closer than ever and appears almost inevitable unless America changes the approach President Trump has been using since he took office. The greatest risk of war with North Korea is not sudden action by Kim Jong Un, but Kim responding to a perceived attack by Trump. North Korea foreign minister Ri Yong-ho drove that home Monday when he called Trump’s threats against his country “a clear declaration of war.”

The United States has been in a technical state of war with North Korea since the end of the Korean War in 1953. Every president since Dwight D. Eisenhower has had to navigate the risk of conflict with North Korea. What’s new is Trump’s bombastic approach to this long-standing challenge — his personal insults, crazy tweets and threat at the United Nations to "totally destroy North Korea."

North Korea’s apparent nuclear detonation on September 3 has drawn our attention to a remarkable international organisation that helps detect and identify nuclear tests.

For the Vienna-based Comprehensive Test Ban Treaty Organization (CTBTO), the latest North Korean explosion was easy to detect and locate. With a seismic magnitude of 6.1 and a blast yield of 160 kilotons (Hiroshima was around 15), the purported hydrogen bomb test mimicked a major earthquake. It was quickly sourced to North Korea’s nuclear test site.

People from Los Angeles and San Francisco are calling me and asking: “Should we be getting our families out of the city? Are we about to be nuked?” The short answer is no. Despite North Korean missile tests and President Donald Trump’s warnings about “fire and fury,” the missiles are not about to fly. All parties have overwhelming interests in avoiding an actual shooting war. That said, there are steps that can and should be taken to reduce the danger of deadly accidents.

On April 25, 2017 China put on public display the Changzheng-1, its first Type 091 Han-class nuclear powered attack submarine. It entered service in 1974 and was decommissioned in 2013.

China launched its nuclear-powered submarine program in 1958, soon after starting its nuclear weapon program. To avoid the nuclear submarine program competing with the nuclear-weapon program for scarce HEU, according The Secret Course, an authoritative book on China's nuclear history, the decision was made to use LEU fuel for naval reactors.