When peaceful nuclear explosions were almost a thing.

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Hello again folks. This week I want to talk about something that seems like an oxymoron: peaceful nuclear explosions. You may struggle to believe this, but both global superpowers investigated using nuclear explosions for non-military purposes. And I don’t just mean that a bunch of mad scientists doodled on a blackboard and wrote a crazy paper or two: they exploded real nukes in their search for scientific merit.

It’s a salutary lesson, perhaps, in what scientists and engineers will get up to when you give them time and money. As Gary Larson put it:

This, of course, happened during the Cold War, when all sorts of mad rocket science was en vogue. The United States exploded nearly thirty nukes as part of their programme. The Soviet Union, well over a hundred, and right up until 1988.

As crazy as they seem to us today, there was a logic to these programmes. I’ll start off by explaining the logic behind peaceful nuclear explosions (PNEs). I’ll illustrate three promising applications for these erstwhile city-destroyers: transportation, excavation, and electricity generation. Along the way I’ll discuss the real-life American and Russian programs. Then I’ll talk about some of the downsides of PNEs, on the off-chance we get carried away and try to reinstate these programs.

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How PNEs could be a great idea

Apologies if you’ve recently read my book review of Annie Jacobsen’s Nuclear War: A Scenario, because I’m going to pull the same quote that I used in that piece:

It has been three seconds since the initial blast. There is a baseball game going on two and a half miles due east at Nationals Park. The clothes on a majority of the 35,000 people watching the game catch on fire. Those who don’t quickly burn to death suffer intense third-degree burns. Their bodies get stripped of the outer layer of skin, exposing bloody dermis underneath.

…

Within seconds, thermal radiation from this 1-megaton nuclear bomb attack on the Pentagon has deeply burned the skin on roughly 1 million more people, 90 percent of whom will die… Most won’t make it more than a few steps where they happen to be when the bomb detonates. They become what civil defense experts referred to in the 1950s, when these gruesome calculations first came to be, as “Dead When Found.”

Just… wow. I can’t find a better description than the above for the sheer destructive power, in all its horror and gruesomeness, of a nuclear explosion. And this, bear in mind, is only describing one cohort of victims. Not the ones who were incinerated in fractions of a second by the flash or were killed by the storm of building debris.

Why in God’s name would we want to mess with that kind of raw power? What possible good could come of it?

The horror of the passage above is (thankfully) fictional: no nuclear weapon has ever been used on Washington D.C. But the horrors of “strategic” bombing, i.e. bombing population centres indiscriminately, are all-too familiar to the non-fictional people who’ve survived them¹.

Military explosions, both conventional and nuclear, have horrific effects on human beings. But conventional explosives, when used for commercial purposes, can improve the lives of billions. Why shouldn’t nuclear explosions be equally transformative, provided they are used far away from people?

That’s the logic behind PNEs, and it’s not crazy. After all, context is the only thing that separates miraculous technology from deadly weaponry. There are plenty of ways that we turn awful destructive military technologies to peaceful ends:

• If you go to a mine and sit next to a bore-hole full of commercial blasting explosives², the resulting shockwave will flay and jellify you just as badly as military plastic explosives would.
• Standing in the exhaust of a rocket will turn you into ash just as effectively as an enemy soldier with a flamethrower.
• And wandering inside a jet engine for a look will chop you into small pieces much more effectively than an entire army of samurai wielding katanas.

Fair enough, you might say, but what possible applications did these mad scientists envisage? I’m glad you asked…

PNEs provide a powerful means of propulsion

Space is big and the Earth is small. Getting to our own Moon takes days using chemical rocket technology. Getting to Mars takes months, and these are in our cosmic backyard. Much closer, actually. If Mars is within breathing distance, then Proxima Centauri, the closest star³, is in the next town over. It would take over a hundred thousand years to reach it, which puts a bit of a dampener on our exploration plans.

Surely nukes can help with this intolerable situation? That was the thinking behind Project Orion, an American attempt to build a nuclear explosion-powered rocket. Real Engineering has a whole video on this, so I won’t repeat the details:

In short, instead of fuel, the spaceship contained many miniaturised atomic bombs. These were to be shot out the back of the craft where they would detonate at a safe distance. The resulting energy pulse would get absorbed by a pusher plate on the back of the spaceship, which in turn would propel the craft forward.

Before you write this off as completely ridiculous, you should know that they actually built a prototype. Well, a miniature one, powered by pellets of conventional explosive—and it flew!

Project Orion died in the early 1960s due to the Partial Test Ban Treaty which forbade nuclear explosions in outer space. You can read more about Orion and “nuclear pulse propulsion,” as it’s called, in this NASA Marshall Space Flight Center report from 2000 (.pdf link).

PNEs can do some very heavy lifting

If we can’t use nukes in space, even peaceful ones, then what about using them on the ground? Surely, no even-minded person could object to that? After all, if you’re trying to create an artificial harbour in Alaska, then why not use a chain of thermonuclear bombs to do the tedious job of lifting out the dirt?

One such plan is shown below, although it looks to me more like a virus injecting its genetic material in blobs into a host cell. That’s why we scale our drawings, I suppose.

The Chariot project depicted above never had any economic rationale. You sense that the engineers who made this plan wanted to do this just to show that they could. It did face concerted opposition from local populations, who were aware of the potential for radioactive contamination.

Fallout is one of the deadly effects of nuclear weapons. When you detonate a nuclear weapon in the air you get maximum lethal effect but minimum fallout. Exploding the same sized bomb underground results in fewer immediate casualties but instantly contaminates millions of tonnes of soil with radioactive fission products and irradiating neutrons.

This contaminated soil “falls out” of the sky later on, downwind of the initial blast, and can expose those poor sods it falls on to ionising radiation. Project Plowshare⁴ was the US PNE programme which involved 35 warheads going bang in 27 tests.

The most notorious test as part of Plowshare was the Sedan nuclear test. They detonated a 100-kiloton warhead underground with the aim of producing the biggest crater possible. I think it’s fair to say that they succeeded:

Although it did produce an impressive crater⁵, it also left a radioactive legacy. It was seven months before the bottom of the crater was safe to walk on without protective equipment. This explosion, along with the other Nevada nuclear tests, is estimated to have exposed residents in downwind counties to a dose of 2 mSv, which is equivalent to 1-2 years of background radiation or some hefty medical x-rays.

The Soviet Union, of course, got in on the act too, with their Nuclear Explosions for the National Economy programme⁶. They carried out an impressive alarming 120 tests, including some actual canal building in 1971 on the proposed Pechora–Kama Canal.

The three “Taiga” devices exploded but the canal was never built. Today a lake sits in the crater created by the PNEs. These devices got an unprecedented 98% of their explosive energy from nuclear fusion, as opposed to fission. Since it’s fission which creates radioactive products and ultimately fallout, this meant that fallout was far lower than comparable tests with other devices.

Just in case you get carried away and think it’s all about the environment, let me tell you about another cornerstone of the Russian PNE programme: nuclear fracking.

PNEs can keep the lights on

One of the obvious things you think of when you see a nuclear explosion is: “Oh wow, look at all that energy. I wonder how we can use that for electricity?” You don’t automatically think this? Oh well, I suppose that obsession is just for 1950s high-trousered engineers.

In the 1970s, the scientists and engineers at Los Alamos National Laboratory proposed a new way to generate electricity, which in their minds was the only then-feasible way of generating power using nuclear fusion⁷. This was a giant steam external combustion engine:

• Step 1: Fill an empty cavern with water
• Step 2: Drop a nuke into the water to make it nice and hot and angry
• Step 3: Vent it through a heat exchanger to heat clean water for a steam turbine, turning a generator, generating electricity
• Step 4: Keep dropping those nukes (they reckoned two 50 kiloton devices per day for 2 gigawatts of power)

This would be an impressive type of power plant, although one has to wonder how well it was thought out when important modules such as “steam electric power plant,” “device assembly,” and “safety” are represented with boxes.

A more common trend in PNEs was detonating the devices underneath shale gas or oil sands to make commercial extraction of the fossil fuels easier. Both the US and the Soviet Union tried this, but results were mixed, and ultimately proved less feasible than using water and sand at high pressures (a.k.a. hydraulic fracturing or just “fracking”).

Using nukes to frack out oil and gas presented some seismic and public affairs challenges, according to scientists at the time. I’d say that’s putting it mildly. Nuke-fracking seems like a reasonable place to take stock and look at the downsides of PNEs.

Conclusion: Why PNEs are a terrible idea

Nobody likes it when you explode nuclear bombs under or near them, and modern democratic governments have to listen to people.

Fallout is a problem when you combine nukes with soil, but perhaps further research would have mitigated that problem. A more important issue is that to make PNEs worthwhile, they need to be big. Pound-for-pound⁹, a nuke is cheaper than conventional explosives, but only for devices bigger than 10 kilotons or so. This imposes a lower limit on the size of the crater or tunnel or chasm you want to build and doesn’t leave much room for finesse.

All of the applications discussed above were impressive in theory, but there were easier, cheaper, safer, and less controversial ways to achieve the same effects. When the scientists argue that more investment into big explosions is not worthwhile, then you know it’s a lost cause.

One last worry about PNEs is nuclear proliferation. If nukes became widely used in industry, they would inevitably be easier for rogue states or terrorists to get their hands on. Even if you locked the weapons down tightly, you’d have a bigger pool of expertise which you could draw from. If “you” are a nice sane democratic government¹⁰, then that’s probably a good thing. But if “you” are a dictator or terrorist leader, then that’s not so great.

I didn’t mention some of the more unusual potential PNE applications such as terraforming Mars or deflecting Earth-bound asteroids. This was because I ran out of space, but also because these latter two are simple concepts, as opposed to the real life PNEs which took place for propulsion, civil engineering, and energy generation (or at least extraction).

One last point before we finish: PNEs may have gone out of fashion today, but the world has seen more peaceful uses of nuclear explosions than warlike uses. Despite all the tests, all the stockpiles, and all the very valid worries about the nuclear hair-trigger, nuclear weapons haven’t been used in anger since 1945. Long may that situation remain.

Thanks for reading and please remember, if you haven’t already, to subscribe using the link below. Please also share this article with a friend and help me get even better reach in 2026! See you next week.

Cover picture: “Sedan” nuclear test crater (1962). This was part of Operation Plowshare. Use the roads in the bottom foreground to get a sense of scale. Picture from US Federal Government, in the public domain, via Wikipedia.

1. In my review of Nuclear War: A Scenario, I pointed out a handful of eyewitness accounts you can access from Hamburg, Dresden, Tokyo, Hiroshima and Nagasaki. ↩︎
2. Nowadays, this would probably be ammonium nitrate and fuel oil (ANFO). In the olden days, it might have been the stereotypical sticks of dynamite with a fuze and blasting cap, as I’ve discussed here before. ↩︎
3. Apart from our own sun of course. ↩︎
4. It comes from Isaiah 2:4: “…they shall beat their swords into ploughshares, and their spears into pruning hooks; nation shall not lift up sword against nation, neither shall they learn war anymore.” Yes, I shamelessly stole this analogy for the title of this article. ↩︎
5. Which helped scientists to validate that the famous Barringer crater in Arizona was caused by a meteorite impact. ↩︎
6. While we’re on the topic: Have you ever heard a more Soviet-sounding name for a program? ↩︎
7. To be fair, subsequent decades have not proven them wrong. ↩︎
8. Yes, really. Between this guy, the “sausage” from last week, and the vaguely suggestive sound of “PNEs,” I’m beginning to worry. Maybe it’s a sign that I’m watching too much RuPaul’s Drag Race. ↩︎
9. I mean in terms of energy output. ↩︎
10. Because we have so many of those… ↩︎