The Trump administration is reported to be considering explosive testing of nuclear weapons. The purpose appears to be entirely political—to press China and Russia into arms control talks. But, it won’t work.
The United States conducted its last nuclear explosive test in 1992. After which, President George H. W. Bush declared a moratorium, passed by the Senate. Those who wish to restart testing claim that Russia and China have recently carried out what are called low-yield nuclear tests. The claim has not been backed up with public evidence. This is not surprising; such tests cannot be detected by satellite or other technical means.
The experiments in question are also called hydronuclear experiments and are very much like subcritical experiments. The difference is that nuclear fission contributes a tiny amount to the explosion in a low-yield nuclear test but not in a subcritical test. The contribution can be detected only by special instrumentation.
U.S. Subcritical Testing
The United States has signed, but the Senate has not ratified, the Comprehensive Nuclear Test Ban Treaty (CTBT). That treaty prohibits tests with any nuclear yield, which includes hydronuclear tests. Russia has ratified the CTBT, but China has not. A nuclear explosive test by the United States would violate the moratorium and the CTBT. If it were done above ground, it would violate the Limited Test Ban Treaty of 1963, which the United States has ratified.
The purpose of nuclear explosive, hydronuclear, and subcritical tests is to improve nuclear weapon design. That includes making them smaller or safer. Since 1992, U.S. nuclear weapons laboratories have used computer simulation and smaller experiments to understand nuclear weapons. Every year, the laboratory directors certify that, to the best of their knowledge, the nuclear arsenal is safe and effective.
An American test would likely be answered by Russian and Chinese tests, and perhaps by others. Although the United States, Russia, and China have mature arsenals and don’t need the tests to improve design, other countries like India, Pakistan, and North Korea would see an American test as an excuse to improve their designs to fit on smaller missiles.
Worst of all would be the signal that the United States is willing to break treaties and brandish the world’s most destructive weapons for political means. After withdrawing from the Antiballistic Missile Treaty, the Intermediate Range Nuclear Forces Treaty, and the Open Skies Treaty, a nuclear test would signal American readiness for a nuclear arms race like that of the 1950s and 1960s. Donald Trump’s tweeted threats of nuclear use would up the ante.
Beyond the bad policy, there is the practical question of how the United States could do a nuclear explosive test. Atmospheric tests at the Nevada Test Site spewed radionuclides over southern Nevada and southwestern Utah, damaging people’s health. The test site is close enough to Las Vegas that people were able to watch mushroom clouds from their roofs and feel the rumble of underground tests. Las Vegas has grown since then, and housing is much closer to the test site.
Scientists and engineers who have participated in nuclear explosive tests are no longer at the national laboratories. In the early 1990s, a program collected oral histories from those workers so that testing might be reconstituted if necessary. But, it is now almost thirty years later.
Many things about testing remain the same—particularly the precautions to keep the tests from venting into the atmosphere. But, some things have changed. Thirty years ago, data collection for a test required miles of cables to send signals of radiation, shockwave, and other information to recording stations. These days, those cables probably wouldn’t be necessary, but the instrumentation would need to be completely rethought. In 2016, John Hopkins, former testing director at the Los Alamos National Laboratory, estimated it would take at least a half a billion dollars and six months to start testing again.
This latest push isn’t coming from the weapons laboratories. Instead, Trump and the people around him want to make a point. So, data collection would not be necessary. However, we might expect the weapons scientists to press for it if there is going to be a test.
The bang might be all that Trump wants, but it’s not going to accomplish the goal of bringing China and Russia to the negotiating table. Instead, it will increase the chance that other countries will resume testing as well, risking new environmental contamination. And, it will erode yet another norm that has helped reduce nuclear risk for decades. Resuming nuclear testing is a very bad idea indeed.