I’ve heard of radiation decay or something. Don’t know if that’s relevant. But nukes. When a country has built one, what goes on with it? Like, do they just put it in a warehouse for a rainy day? Do they polish it everyday? Do they rust and decay after many years? Are they maintained or decommissioned and new one built?
I know certain countries have nukes for decades. Just wondering if they’re continously manufactured and the old ones disposed of or upgraded or???
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Nuclear weapons decay over time because of the natural decay of the radioactive material. The Uranium and Plutonium in their cores slowly decays into other radioactive materials eventually contaminating the core enough that it is no longer reliable.
And just like anything else nuclear weapons require a degree of maintenance to their electronics, propulsion, explosives, etc etc.
So an Nuclear weapon like any other weapon system has a shelf life.
Nuclear weapons are stockpiled in bunkers and warehouses along with everything else the Military needs. They are tracked and inventoried, and sent back to the manufacturer on occasion to be maintained or replaced. That is when they aren’t in active service (IE onboard a carrier, in a submarine missile tube, or inside a bomber)
The big military powers are always producing new nuclear weapons in small quantities and replacing the older ones which are decommissioned and disposed of.
This is not just a matter of shelf-life either. Delivery systems change with time, so all the nukes that worked with 1 class of submarine won’t necessarily work with another for example.
A lot of the Nuclear inventory in the world is old and past it’s life expectancy though. There’s a reasonable chance a lot of the older nuclear weapons wouldn’t work if used.
Yes, a lot of the nukes are seriously out of date. Some of the facilities used to make them have been disassembled too, and many of the staff who have the absolutely priceless institutional knowledge used to manufacture them will have retired.
Some of the nuclear material will have progressed on its often centuries-long journey towards turning to lead, too. But I think that you are right that the technology surrounding the nukes decays faster than nearly all the fissiles involved.
The explosive bits of refined uranium or plutonium will decay over thousands of years. The warheads don’t need much maintenance. They’re kept securely under good conditions. A few large blobs of radioactive metal are brought together using small internal explosive charges and they do their magic. The warheads are made of materials that won’t rust out and don’t need to be opened or modified, but they’re still inspected regularly.
The warheads are interchangeable, and can placed into the missile immediately before the missile is loaded on the aircraft or missile launcher.
The missile itself is filled with fuel, and just like the fuel in your car it will go bad with time. Modern missiles are like small airplanes, with wings and fins that move motors to steer, computers to guide it, and so on. They have batteries for power that will need to be replaced regularly. They have engines that need to be maintained, need to be inspected, and kept working.
And just like your guess, the missiles themselves are often disposed of, but with different warheads attached. Often the old missiles are used for testing and training and replaced with new ones.
It depends on the design of the warhead and the missile.
Many nuclear warheads today use radioactive tritium as part of how they work. So after 6 years you will have a quarter as much as before. That’s rapid-enough that it means you have to refresh and refill the tritium reservoirs every few years if you want the nuke to work as intended.
There are also electronic components in the warhead that need to work right. Over time these will corrode and wear out like all electronic components.
There are chemical explosives in the warhead that will slowly undergo chemical reactions, and are being irradiated by the radioactive material in the warhead, which creates other chemical changes. So these need to be inspected and swapped out over long periods of time.
The radioactive fuel in the weapons also undergoes decay, but this is very slow. So far it is not clear that this makes the weapons unreliable on a short (e.g. decades) time scale, but over a very long period of time, it would affect it. These materials have half-lives that range from tens of thousands of years to hundreds of millions of years.
The missile itself is a big chemical reaction waiting to happen. If it is liquid-fueled it needs a lot of maintenance, because liquid fuel is corrosive and leaks and can create a lot of hassles. If a liquid fuel missile’s internal pressure gets too low, it can collapse and explode, for example (the missile tube is sort of like a soda can — when the internal pressure is high, it can take a lot of weight, but if you poke a hole in the side, the can is easily crushed).
Solid-fuel missiles don’t require as much maintenance. They are lower performance, but the major advantage is you don’t have to tinker with them as much as they aren’t as likely to be an accident hazard. Most nuclear missiles today are solid-fuel for this reason.
Nukes are no longer continuously manufactured in the United States, but they are in some countries. The existing nukes are monitored very carefully to make sure they will work as desired, and old warheads are being “upgraded” so that they can last longer than they were initially intended to (during the Cold War, nuclear warheads were replaced by new ones every 10-20 years or so; since the end of the Cold War, there aren’t new ones being made, with some recent exceptions).
>I’ve heard of radiation decay or something
Speaking to this specific point, it’s related to a specific type of nuclear weapon- The [Boosted Fission](https://en.m.wikipedia.org/wiki/Boosted_fission_weapon) Bomb.
At some point, we figured out that by injecting gaseous tritium into the core before detonation, you get a thermonuclear reaction that massively increases the bomb’s yield.
Tritium has a relatively short half life, so it will decay away over the decades a bomb can spend in storage. Periodically you need to refresh the tritium charge to ensure the weapon will function.
Nuclear warheads (I’m leaving out the delivery systems because that’s another topic) do in fact have a shelf-life. Over time, components decay and deteriorate and need to be replaced and maintained.
Nuclear warheads have several major component groups. First is the pit. That’s usually plutonium in American weapons, but it can be uranium as well. Uranium and plutonium undergo radioactive decay, so over time, they’ll decay to the point where they can’t sustain a fission reaction anymore. Assuming the weapon is maintained properly (i.e., not exposed to moisture or the elements or contaminants), American pits are projected to have a service life of 90 years, but plutonium is very reactive, so any contamination or exposure to other chemicals or moisture could corrode the pit and render it inoperable much sooner. After 90 years, the decay of the plutonium might make them unreliable. Uranium has a much longer half-life so uranium cores should last longer.
The next major component is the conventional explosive that start the fission chain reaction. These explosives can chemically decay over time, and could also potentially deteriorate from long-term exposure to the radiation emitted by the pit. I don’t have a time frame for you on that, but I imagine it’s at least as long as the lifetime of the pit.
Next up is the fusion fuel, which is required for the warhead to be a thermonuclear warhead and not just a plain fission bomb. All of warheads in the U.S. arsenal are thermonuclear. Of of the components of the fusion fuel is tritium (hydrogen 3). Tritium has a half life of only 12.3 years, so the tritium in each warhead has to be replaced every 10 years or so, otherwise it won’t work.
Finally, there are all the electronic components such as the battery, pyros, and other circuitry required to initiate the explosion. Again, I don’t have any info on this, but at least a few decades seems reasonable.
All that said, no one really though about service life when they were making these warheads because it was just assumed they would keep making new ones, but the end of the Cold War brought an end to new warhead production, but now, even the newest warheads in the U.S. stockpile are almost 30 years old, and no one really thought we’d have to contend with that, so the Department of Energy, which is responsible for storing and maintaining nuclear weapons, has ongoing studies to determine the effects of aging on the warhead stockpile. At some point, they’ll need to be decommissioned or replaced, but exactly when that will be is unclear.
Multiple issues.
1. Tritium. Pretty much all modern nukes are fission-fusion, i.e. the uranium part of the bomb is used to trigger a fusion reaction, which is fueled by tritium (hydrogen-3, half life 12 years). After 12 years, half the main explosive charge of tritium has decayed to helium, which doesn’t help the reaction and probably actually damps the reaction.
2. Corrosion of the plutonium/uranium. This may not be a problem anymore, but used to be.
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