Editors’ Note

Even before the invention of nuclear weapons, there was concern they would be enormously and indiscriminately destructive to civilian populations. In their pathbreaking secret memorandum to the British government in early 1940, “On the Construction of a Super-bomb, based on a Nuclear Chain Reaction in Uranium” which helped lay the basis for the nuclear weapons program in the UK and later the United States Manhattan Project, Otto Frisch and Rudolf Peierls noted that “some part of the energy set free by the bomb goes to produce radioactive substances, and these will emit very powerful and dangerous radiations... . Some of this radioactivity will be carried along with the wind and will spread the contamination; several miles downwind this may kill people... . Owing to the spreading of radioactive substances with the wind, the bomb could probably not be used without killing large numbers of civilians, and this may make it unsuitable as a weapon for use by this country.” During the Cold War, it was well understood that any nuclear attack aimed at destroying an adversary’s nuclear or conventional forces could result in very large numbers of civilian casualties in the targeted country, perhaps regionally, and possibly even globally for a large enough attack with high-yield weapons. This remains true today. In the opening article of the issue, “Radioactive Fallout and Potential Fatalities from Nuclear Attacks on China’s New Missile Silo Fields,” S ebastien Philippe and Ivan Stepanov present an analysis of the consequences of a nuclear attack on three relatively remote areas where China is believed to be constructing hundreds of silos for deploying intercontinental ballistic missiles. The authors model a possible attack on these silos, assuming that to achieve an acceptable kill probability the attacker uses two warheads against a silo and detonates them very close to the ground (which is consistent with public information about U.S. nuclear war plans). The analysis models the significant radioactive fallout from these near-surface nuclear explosions, using advanced atmospheric particle transport software and weather data to evaluate the dispersion of the fallout and population exposure in cities at long distances. Estimates of casualties depend on the specifics of the scenario, but as the authors demonstrate, an attack on the alleged silo fields in China is likely to result in tens of millions of unintended but to be expected civilian deaths from acute radiation sickness. The authors note “Many more would suffer from long-term effects of radiation exposure and die prematurely.” They suggest that such dire humanitarian outcomes should compel policymakers to revisit decisions about siting and attacking missile silo fields. The second article in the issue, “Simulating the Passive Neutron and Gamma Signatures of Containerized Nuclear Warheads for Disarmament Verification,” deals with a completely different side of nuclear weapons. Svenja Sonder, Carina Prunte, Yannick Fischer, Manuel Kreutle, Jan Scheunemann, and Gerald Kirchner discuss methods for detecting the presence of a plutonium-based weapon in a closed container. The analysis uses numerical simulations with the Geant 4 code to consider the cases of a simplified fission weapon and of a two-stage thermonuclear warhead, as well as a small amount of plutonium in a scrap container with different assumptions about