author: niplav, created: 2024-01-30, modified: 2024-04-18, language: english, status: maintenance, importance: 8, confidence: certain

Testing nuclear weapons is actually good, because it removes incentives to build more & different weapons as a response to uncertainty about reliability. The nuclear powers should therefore resuming nuclear weapons tests.

Two Reasons For Restarting the Testing of Nuclear Weapons

Nuclear testing was largely phased out by the Comprehensive Nuclear-Test-Ban Treaty in 1996, with the exception of non-signatories like India, Pakistan (both last testing weapons in 1998) and North Korea (tests during the 2010s).

I see two strong arguments in favor of restarting some limited nuclear tests, and a couple of weak counter-arguments.

Reinstating such tests would include public announcement of their time & place, with penalties for unannounced tests.


  1. Testing of warning systems: Early warning systems malfunctioning present a large risk of normal events being mistaken as attacks, with correspoding nuclear counter-attacks. Reading through the FLI Close Calls Timeline, I identify 7/28 events as being clear examples of malfunctioning early detection systems as causes for close calls (e.g. "Lost Contact with 50 Missiles", "Six Mis-Routed Nukes", "Soviets Misinterpret US Nuclear War Games" (which would be much easier under a setup where announced military testing was expected and acceptable), and "False Alarm During DEFCON 3") and 6/28 more as being at least linked to detection systems malfunctioning ("Norwegian Rocket Mistaken for ICBM", "Soviet Union Detects Incoming Missiles", "Faulty Chip Signals Soviet Attack", "Power Failure Mistaken for Nuclear Blasts", "Missiles over Georgia"). However, there is at least one case in which a test was perceived as an attack ("Soviet Missile Headed Toward US?") — could this one have been avoided if announcing nuclear tests was common? Additionally, some false alarms (e.g. "Tampa is getting nuked") result from participants mistaking training tapes for real attacks, which would not happen as much in the case of real-world tests. Having real-world nuclear tests occurring regularly might be a time to test early detection systems and thereby guard against false positives by increasing the specificity of early detection systems, thereby lowering the risk of accidental escalation based on faulty information. My best guess is that operators of those early warning systems are very uncertain about their reliability, and would become significantly more relaxed if they had real-world information to calibrate on.
  2. Reducing redundancy: Similarly, unless covert nuclear testing is occurring (which I consider unlikely10%, given the related intensive monitoring), I expect there to be significant uncertainty in the military commands of nuclear states about the reliability of those weapons, with conservatism about the reliability of those weapons leading to larger stockpiles ("If we don't know whether our weapons work, it's probably better to make more & different ones."). This uncertainty probably leads to an effective number of nuclear weapons that is larger than strictly necessary for military purposes, and has large negative externalities—the weapons would probably still be used in a nuclear conflict. Nuclear testing could reduce this uncertainty about the reliability of the weapons, making reductions in stockpiles more realistic. If I imagine having to rely on weapons that haven't been tested in more than 30 years, I'd also want to err on having more of those weapons rather than less.

The reduction brought challenges: if the U.S. could no longer build or design the next world-altering bomb, what could government officials do to retain the expertise of scientists? And how would the ensure the integrity of the arsenal without being able to test the products? Nuclear bombs contain more than 4,000 parts, and most of those parts are now more than 30 years old. Ask yourself: If you left a 1993 Ford Mustang in the barn—a temperature-controlled vault of a barn, but a barn nonetheless—would you feel 100% certain that everything would work properly when you turned the ignition? Oh, and don’t forget that your life may depend on it. The answer the Energy Department came up with was to harness computer simulations and experiments to evaluate the reliability—and extend the life spans of—America’s nuclear weapons. The most vexing dilemma was assessing plutonium, an element only discovered 80 years ago. To find out how it ages, Los Alamos ran experiments in the early 2000s that found plutonium pits changed over the years in ways that could impact weapons’ performance. But the studies couldn’t provide specifics on when exactly plutonium aged out.

—W. J. Hennigan, “In the Lab Oppenheimer Built, the U.S. Is Building Nuclear Bomb Cores Again”, 2023


There are some counterarguments to restarting the testing:

  1. Tests as cover for attack: More tests would mean that countries could mistake tests as attacks, or tests be used as a plausibly deniable scenario in which to strike first (perhaps even masking the attack as an accident). This risk could be strongly reduced by requiring public announcements of the tests e.g. a month ahead. Additionally, usually tests involving a single nuclear weapon, and thus would be not great as attacks.
  2. Environmental impact: Wikipedia states that nuclear fallout has lead to an excess of ~11,000 deaths due to nuclear radiation. Resuming (restricted) nuclear tests would likely have similarly high externalities—could these perhaps be mitigated in some way, such as testing in very remote (internationally shared?) locations, such as the Antarctic?
  3. Making more powerful weapons: Nuclear tests might enable the development of even more powerful nuclear weapons. I'm not sure how bottle-necked the development of bombs with higher yields is on experimental data: the reason I know about the limit of the size of nuclear weapons is that "there is no target big enough to be hit by them". If this is not true, then more destructive nuclear weapons developed using experimental data would be negative for the world. (Relatedly, I'm not sure whether, if nuclear testing allow for weapons with higher precision, that would be good or bad for the world: nuclear strikes would have fewer externalities, but leaders might also be more willing to use nuclear strikes due to lower civilian casualties (and thereby increasing the risk of nuclear escalation)).

Ideal Policy Situation

The ideal policy situation that looks achievable to me (as it looks like it doesn't directly go against any nation-states interest) would look like this:

  1. All nuclear powers in the world sign a treaty governing how nuclear weapons should be tested.
  2. Whenever someone wants to test a nuclear weapon, they announce details of this test a month in advance.
    1. The blast yield.
    2. If ICBM:
      1. Launch datetime & location.
      2. Touchdown datetime & location.
      3. The trajectory.
      4. Whether the ICBM will contain a nuclear warhead.
    3. If nuclear warhead:
      1. Detonation datetime.
      2. Detonation location.
      3. The blast yield.
      4. The type of weapon (thermonuclear, fission weapons or others).
  3. Only one test a week is allowed.
  4. If one party of the treaty uses a test for a covert attack, all other parties of the treaty attack the perpetrator.