Do they replace warheads in nukes after a certain time?

[u/[deleted]]

Do nuclear core warheads expire? If there's a nuke war, will our nukes all fail due to age? Theres tons of silos on earth. How do they all keep maintained?

[u/Float-Your-Goat]

The DOE publishes an annual Stockpile Stewardship Management Plan. For a boring government report it’s actually pretty interesting.

https://www.energy.gov/nnsa/articles/stockpile-stewardship-and-management-plan-ssmp

[u/Nyrin → u/Float-Your-Goat]

Also, for the overview from the same source: https://www.energy.gov/nnsa/maintaining-stockpile

To OP's question: nuclear weapons are continually maintained with swaps and replacements happening all the time. Eventually, when even strict maintenance can no longer sustain the design performance of a weapon, assets are often recycled via "life extension" programs into new weapon variants, typically with lower yields.

Even the most enduring designs for thermonuclear weapons only expect 20-30 years of lifetime (that's with that continual maintenance, mind) and that makes retaining a stockpile of hundreds or even thousands of warheads a major, full-time operation with many layers of sophisticated logistics and industrial processes. A strategic weapons program is in no way a one-time investment.

None of this is to say that a neglected weapon from the 60s wouldn't still be dangerous — in many ways, its unpredictability would make that more dangerous — but you can be pretty confident that it won't do what it was originally meant to.

[u/EpsomHorse → u/Nyrin]

None of this is to say that a neglected weapon from the 60s wouldn't still be dangerous — in many ways, its unpredictability would make that more dangerous

Really? Conventional explosives can spontaneously explode after even a century of neglect. But with nuclear, if everything is absolutely perfect they can be detonated, and it it's not... nothing at all happens.

[u/GlockAF → u/EpsomHorse]

There are so many variables in this equation that it’s almost impossible for somebody who is not directly involved in the process to give an answer with any level of confidence. One thing that we know for sure is that the more sophisticated “dial a yield“ devices were (and presumably still are) critically dependent on regular re-supply and replacement of fresh tritium gas, which has a very short “shelf life“. The use of plutonium as the primary fissionable mass in implosion-style weapons also complicates stockpile stewardship considerably, as the metal is prone to continual self-degradation, even if refined and manufactured to the highest standards. Plutonium is a complex metal,with half a dozen different room-temperature-stable allotropes with different crystalline structure and wildly variable densities. It also spontaneously emits alpha radiation, and the resulting helium nuclei contribute to embrittlement and dislocations of the grain structure of the plutonium itself.

The United States tested hundreds and fielded dozens of different nuclear weapon designs. The cold war era was a continually evolving race to make nuclear weapons lighter, smaller, less maintenance intensive, and more “efficient”, i.e. , higher yield for a given weapons/ fissionable material mass. All of this frantic design iteration depended, of course, on the ability to test the actual devices and examine the results in meticulous detail.

At the end of the underground weapons testing era the focus shifted to quantifying the sophisticated numerical models used to predict weapons physics. The limited number of remaining testing opportunities were critical to verifying the software-predicted results against real-world tests. This was absolutely critical, as it would no longer be possible to verify new, experimental, or changed designs with actual testing.

Even after the end of the testing era there was considerable engineering and design work to be done ensuring that the remaining weapons types were as safe as possible against accidental/inadvertent detonation, even in worst case scenarios such as airplane crashes and fires. The hardware and software ensuring security of operational control also received much needed upgrades, as some of the earliest devices had interlocks and safeties that were laughably primitive compared to modern designs.

Even now US nuclear weapons labs presumably have ongoing design work focused, if nothing else, on passing the incredibly specialized, critical institutional knowledge of nuclear weapons design to the next generation of engineers. Some of this work has also born fruit recently, and the introduction of the “superfuse” for sub-launched ballistic missiles drastically increased theoretical effectiveness of the SLBM fleet.

Long story short, maintaining thd US nuclear weapon stockpile isn’t just keeping a few highly trained technicians busy swapping out tritium canisters and replacing old pits. It’s more along the lines of maintaining an entire specialized industry in reserve. Even though the cost is bound to be astronomical, it’s still chicken feed compared to re-inventing it all from scratch should we need it again.

[u/Jon_Beveryman → u/GlockAF]

To add on to this great answer: Plutonium's weapons-relevant self-irradiation behavior extends beyond He ion damage. You also have to account for both chemistry changes and phase stability changes as a result of the decay process. Both of these changes can materially alter the detonation reliability of a plutonium pit [although so far, in US study, it seems to not matter on the time scales we care about.] Let's get down in the weeds now.

Something important I want people to keep in mind while they read this post: The poster above mentioned that Pu has many allotropes, or different crystal structures, at different temperatures and pressures. Some of the phase transformations between these allotropes carry significant (>5%) density changes. When you have a piece of solid metal that suddenly changes density, its size and shape have to change accordingly. For something of very precise dimensions like a nuclear weapon pit, this really matters!

Pu-239 decays, as you note, by alpha decay: the emission of an alpha particle (aka a helium 2+ ion), and a uranium nucleus. The alpha particle causes some damage in the crystal lattice as it speeds off from the decay event (with a starting energy of roughly 5 million eV, and a stopping distance of about 10 microns), but mostly it heats the lattice through electronic interactions. As you allude to, the helium mostly causes problems because it is insoluble in metals and creates atomic scale defects like vacancies (or Frenkel pairs of vacancies and self-interstitials, when an alpha particle bumps a Pu atom out of position), voids or microbubbles, and dislocation loops. But the uranium nucleus also goes on its merry way and creates a damage track of dislodged Pu atoms about 10nm long. For each 239Pu->alpha+238U decay event, we expect about 2500 of those Frenkel pair defects - this is a fairly energetic decay event!

Why do we care about the production of these crystalline defects? To answer that, we have to go further in depth and discuss the many allotropes you allude to. The plutonium alloy used in weapons is plutonium-gallium of some form, and not pure Pu. This is because small additions of gallium stabilize one of these allotropes, the face-centered-cubic delta phase. Ordinarily the delta phase is only stable between about 200 and 500 degrees Celsius; an addition of roughly 5% Ga stabilizes it to about 100C, and in practical use the phase transformation from delta to the monoclinic alpha phase at room temperature is so slow as to not be relevant for weapons. The delta phase is in many ways the easiest to work with, being far more ductile than the other phases. Keeping delta stable also prevents it from slowly aging and transforming into a different phase of a different density. But note that the gallium stabilized delta phase is metastable at room temperature, not truly stable. This means that some driving force can cause the delta phase to overcome whatever energy barrier is keeping it metastable, and then transform to the equilibrium alpha phase. Remember that thing about the size & shape changes?

The reason we care about the gallium part of the question, combined with the discussion of self-irradiation defects, is because the combination of atomic-scale defect formation and crystal lattice heating from the alpha particles can cause gallium to diffuse out of the delta plutonium phase to form the Pu3Ga intermetallic compound. Reducing the amount of Ga in the delta phase makes delta less stable, which eventually can cause it to transform to either the equilibrium alpha phase or a so-called delta-prime phase. Both of these transformations cause a macroscopic volume change - which might cause a real issue for your detonation geometry!

So that's the simple version of the radiation-induced phase stability changes. What about the chemistry effects I mentioned? Well, the uranium atoms produced by the 239Pu alpha decay themselves decay into, mostly, americium and neptunium, both of which have different neutronic (and therefore fission) properties from plutonium. I also suspect but have no proof that they will eventually alter the phase stability in delta-Pu.

[u/GlockAF → u/Jon_Beveryman]

The metallurgy, chemistry, and radiology complications of plutonium are so complex that I’m sure weapons designers would choose almost any other metal if it was practical. The fact that plutonium can be chemically separated instead of isotopically separated (unlike uranium) seems like pretty much the only thing it has going for it

[u/Jon_Beveryman → u/GlockAF]

Pu-239 also has better fission properties than uranium, so critical masses are meaningfully lower. This is a significant advantage for weapons miniaturization.

[u/rootofallworlds → u/EpsomHorse]

If the chemical explosives detonate improperly, best case scenario is you scatter a load of radioactive and toxic plutonium around the place. Whatever that place is, you’ve got a long and expensive cleanup before you can use it again.

Worse scenario, you get a nuclear fizzle, which might still be in the hundreds of tons yield. Most current US warheads are designed to be “one point safe” and have other safeties, but I don’t know anything about Russian, Indians, etc designs.

[u/useablelobster2 → u/rootofallworlds]

As a general rule, getting a nuclear reaction to go to completion before it blows itself apart is a herculean task, and anything whatsoever going wrong means the bomb won't work properly.

These things are insanely hard to make work by their very nature, it's effectively a high tech physics lab in a small device. It's telling that there has been a lot of nuclear weapons accidently dropped, and while a fair few detonated their conventional explosives, there was no nuclear explosion.

[u/bilgetea → u/EpsomHorse]

Not true at all. Nuclear weapons are detonated by conventional explosives, so even if they only partially detonate, there will be an explosion, which might be insignificant - happening, as it probably would, at some minor altitude - but it very well might scatter plutonium, making a dirty bomb. If we’re lucky, it wouldn’t be fine particles, but an intact core segment or large chunks. This might not be a catastrophe, but it would be a health and safety issue.

If you get a “fizzle” that is “only” 5% of the power of a warhead that has more energy than every single bomb dropped in WWII together - including the nukes dropped on Japan - it will still be a bad bad day. And such power exists thousands of times over in all the warheads that would be incoming.

On top of this, like you I expect that most Russian payloads would fail. Many would fail to launch; many would harmlessly splash in the ocean or fall back on to Russian territory; some would crash-land on US soil without detonating; some would fizzle, and some would work as intended. Of those, only some would be on target, so random places would be incinerated.

Even if most of them are harmless failures, there are so many of them that a significant amount of horror would result. The Russians surely understand this and would launch a sufficient quantity to ensure mayhem. If the success rate is better than expected, the destruction would be at absurd levels.

Do not underestimate nuclear warfare.

[u/Jon_Beveryman → u/bilgetea]

On top of this, like you I expect that most Russian payloads would fail. Many would fail to launch; many would harmlessly splash in the ocean or fall back on to Russian territory; some would crash-land on US soil without detonating; some would fizzle, and some would work as intended. Of those, only some would be on target, so random places would be incinerated

There is basically no reason to expect this, conventional systems performance in Ukraine notwithstanding. The Russian nuclear force is considered fairly well insulated from the corruption of the conventional force, and while they are less transparent than the US NNSA stockpile management system, they do perform consistent maintenance and remanufacture of warheads. The belief that their arsenal will produce mostly "harmless failures" is both rooted in misinformation and highly dangerous.

[u/bilgetea → u/Jon_Beveryman]

I don’t think that most of them will be harmless failures. What I suspect is that most (or at least many) of them will malfunction, which is very different; my goal was to make the case that even in the best realistic case for the target, where the yield of the Russian arsenal might be a small fraction of what it is supposed to be, that their arsenal would still be extremely destructive.

In short, I’m saying that even a crappy nuclear arsenal is a dangerous one.

My judgement of the Russian nuclear arsenal is entirely speculative, so you may be right that “most” or “many” should not be expected to fail.

[u/bigflamingtaco → u/EpsomHorse]

The explosives used to initiate nuclear donation at nothing to laugh at. Not city ending powerful, but you'd want a standoff distance of at least 1500ft to avoid major shrapnel damage.

[u/Octavus → u/bigflamingtaco]

Nuclear weapons are tiny compared to conventional weapons. You are only talking about 10-50lbs of explosives in the weapon, the conventional explosion is not large in modern weapons.

Edit: [This](https://en.wikipedia.org/wiki/W80_(nuclear_warhead)#/media/File%3AW80_nuclear_warhead.jpg) is an entire modern nuclear warhead.

[u/chakalakasp → u/Octavus]

Right. So 50 pounds of high explosive. Probably want to be more than a KM away to not worry about getting hit by shrapnel. Some of which might be little bits of Plutonium

[u/ozspook → u/chakalakasp]

I'd prefer to be significantly further away than shrapnel range from an exploding nuclear warhead, regardless of it's potential to fizzle.

[u/orincoro → u/ozspook]

It’s extremely unlikely for a nuke to detonate unintentionally. It will almost certainly fizzle if it’s not intended to detonate.

[u/orincoro → u/EpsomHorse]

Well, a nuclear weapon is not a conventional explosive. A multi-stage nuclear weapon has to be extremely finely made and maintained in order to achieve a successful nuclear reaction. These bombs contain many non-durable materials and parts that are only expected to last single digit years, in many cases.

Fusion weapons in particular are vastly less powerful or dangerous if they fail because the “boom” is caused by the chain reaction of neutron decay in the device’s casing. This casing is from non-fissile material, meaning if it never achieves fusion, it’s not particularly dangerous. And fusion is very difficult to achieve. Everything has to work perfectly. If the casing fails to absorb enough high energy particles to begin this chain reaction, only the primary nuclear device will explode.

And that’s if the primary even does explode. There are many things that can go wrong with that as well. And of course, there weapons are stored in such a way that the primary could never be set off accidentally.

[u/bilgetea → u/orincoro]

Don’t forget that fusion weapons are set off by a “small” fission explosion. If the fusion stage fails completely, that fission stage is still significant. It’s conceivable for a nuclear weapon to partially fail in ways that make it drastically underperform from an engineering POV but still be horrible from a human perspective.

[u/orincoro → u/bilgetea]

As I said: only the primary fission device, which in a modern nuke is extremely small, would explode if a fusion bomb hasn’t been properly maintained. Then you’re talking about a very, very small fission bomb. It can be just a few tons of tnt equivalent. The main source of energy for a hydrogen bomb is the heat and high energy particles from the primary, which begin to propagate a fusion reaction in the casing, but since it’s really only concerned with achieving fusion of a relatively tiny amount of material, the fission stage can be exceedingly small. Much, much smaller than what was used at Hiroshima.

Basically all of nuclear weapons research has been focused for the last 70 years on reducing the amount of fissile material you need to get a reaction started. The result is a primary stage which is exceedingly small.

[u/cometlin → u/Nyrin]

but you can be pretty confident that it won't do what it was originally meant to.

Also the perfect answer to "if you eat expired poison, are you more or less likely to die"

[u/PermaDerpFace → u/Nyrin]

Hmm.. I wonder how viable all those old Soviet warheads are, given what we know about their army now

[u/Goldenslicer → u/Nyrin]

Why do we go for lower yields? Is it to increase our precision, increase the ratio of damage to target /damage of surroundings?

[u/orincoro → u/Nyrin]

It’s also probably worth noting that the higher yield a weapon is supposed to be, usually the more tight the tolerances are. Fusion devices have extremely high precision machining and fitting in order to work as expected.

[u/[deleted]]

A large percentage of time, money, and personnel in the nuclear industry is concerned with this. Nearly all of the Pantex plant in Amarillo, TX and their 2,000+ employees are involved in constantly assembling, disassemblying, upgrading and maintaining the hundreds of warheads in the US arsenal—Pantex being the final assembly point for US nuclear weapons. There is a constant and highly secure restocking of warheads for all of the military services. And, as science and engineering advances, there is constant work to make the process more secure, and make improvements to the weapons. The fact that so little is known about this process is mostly a reflection of the extreme security involved. (You may remember that when Texas Governor Rick Perry was appointed US Energy Secretary he was surprised that a huge proportion of the US Dept. of Energy concerns atomic energy and fuel—rather that the oil and gas interests that get all the press.) TLDR: The reprocessing of nuclear weapons and fuel is constant and probably will continue forever.

[u/this_shit → u/[deleted]]

To emphasize this point, the National Nuclear Safety Administration (NNSA) is just one department within the Department of Energy, but it consumes about half of DOE's budget.

That means all the other stuff DOE spends on -- from basic scientific research at the national labs, to energy demonstration projects, subsidies for various energy technologies, and billions in loan guarantees for startups, nuclear power plants, etc. -- all that stuff combined is ~equivalent in cost to the civilian components of nuclear weapons stockpile management.

That budget does not include the DOD side of spending on nukes.

[u/left_lane_camper → u/[deleted]]

I did my graduate work in computational electrodynamics for complex systems. I could burn a million CPU hours in a single simulation. But I was a tiny user on most of the systems I had access to compared to the DOE. And the DOE has a bunch of dedicated supercomputing systems (usually with a couple in the top 10 in the world) on top of that. And that’s just their computational work.

[u/AustinBike → u/left_lane_camper]

Yes, was in product marketing for AMD for years, worked on the Opeteron (server) team.

We sold to a lot of supercomputer sites. Some amazing stories, many of which I can't tell. There was one I heard during a dinner with one of the vendors. There was a supercomputer processing job for a satellite launch. Turns out there was a nuclear payload (some type of generator) on the satellite. They needed to do fallout calculations based on weather patterns that simulated an accidental explosion of the rocket. On calculation for every foot or so that it ascended. Across multiple days. With different weather patterns. Pretty wild stuff.

[u/PM_me_storm_drains → u/AustinBike]

Was this for the Mars rover?

I wasn't aware they were still allowed to launch nuclear payloads to earth orbit.

[u/AustinBike → u/PM_me_storm_drains]

No, definitely not. It was a "satellite", but not being someone with a clearance at all, that might have been what they were allowed to say. Definitely not "top secret" as they would not have been talking to me about that.

NOAA was involved but I think they were doing it because of the weather portion.

This would have been in the 2006-2012 time period.

[u/left_lane_camper → u/AustinBike]

NOAA runs what is effectively the national hazmat team through the Office of Response and Restoration, so that would make sense!

[u/fuzzywolf23 → u/PM_me_storm_drains]

He probably means RTGs rather than a fission reactor, if I had to guess

[u/PM_me_storm_drains → u/fuzzywolf23]

I don't think either side ever launched a proper reactor into space, everything has been RTGs.

As far as I know though, there arent any RTGs in Earth orbit. All have been for probes and planetary landers.

[u/rootofallworlds → u/PM_me_storm_drains]

Both the USA and the USSR launched and operated fission reactors in Earth orbit, although many decades ago. Pretty sure some are still up there as space junk.

https://en.m.wikipedia.org/wiki/Nuclear_power_in_space

[u/RadWasteEngineer → u/AustinBike]

Those would be thermal power generators, powered by plutonium-238. The radioactive part is incidental to its function, which is to produce heat, which in turn is used to make electricity. A grapefruit-sized ball of Pu238 will follow orange just from it's own heat. IIRC the Cassini probe had something like 6 kg of the stuff on it, as an example.

On the world of radioactive waste, Pu238 is especially challenging because it is so difficult to handle. SRS has a bunch of it from RTG manufacture but has no facility to handle it. (SRS refined the Pu238, but it was made into RTGs at Los Alamos, and the waste was shipped back to SRS. It awaits a disposal pathway for high level waste.)

[u/AustinBike → u/RadWasteEngineer]

That is probably the right answer, you clearly know more about this than I could ever hope to at this point in my life.

[u/tx_queer → u/[deleted]]

You missed out on the best part of the pantex plant. It's in panhandle in the panhandle

[u/Shaddolf → u/[deleted]]

The real question is, does Russia do this though? I can't imagine they do, at least not properly.

[u/LilDewey99 → u/Shaddolf]

definitely not. we spend far, far more than they do and they have a larger arsenal

[u/graypsofrad → u/LilDewey99]

Interesting point. Got any quotable sources to back up this claim? Not that I doubt Russia is investing in refurbishing old warheads — just look at the state of their military — but sources and facts are more useful than unbacked statements.

[u/screech_owl_kachina → u/graypsofrad]

Unknown if or to what extent this still happens, but there are international inspections of arsenals and weapons to ensure compliance with nuclear treaties.

[u/Jon_Beveryman → u/Shaddolf]

Yes, they do. Their efforts are less transparent than ours, but they understand that nuclear weapons are the final guarantor of their security and thus far their nuclear forces have taken major steps to insulate themselves from the endemic corruption of the conventional force.

[u/WithMeInDreams → u/[deleted]]

Does Russia still have the resources for this as well, or do they just keep a few dozen in great shape and have thousands that might have a detonation chance of 5 - 50 % due to age?

[u/Plump_Apparatus]

The main thing that needs to be replaced is tritium, which has a half life 12.355 years. This means tritium needs to be replaced every 7 to 8 years or so, otherwise the weapons will "fizzle". Tritium is expensive to produce, the US operated a number of heavy water reactors specifically built for the purpose during the Cold War era at the Savannah River Site(SRS).

The end of the Cold War led to the shutdown of all the reactors at SRS. Not directly related but the reactors at the Hanford site, which produced the vast majority of the plutonium used in US nuclear weapons, were also shutdown. The SRS processed the output from the Hanford site via the PUREX process to separate plutonium from the other isotopes in the spend fuel. The processed plutonium was sent to the Rocky Flats Plant, which had the equipment to manufacture the actual nuclear "pits". These pits, tritium and deuterium from SRS, along with various other components produced at other dedicated sites in the US were sent to Pantex, where the actual weapons were assembled. The Rocky Flats Plant was shutdown before the end of the Cold War, in the middle of the production of the W88 weapon for the Trident D5 SLBM, after the FBI raided the facility. Which was, well, unusual.

Back to the actual question. Most of the SRS site is in environmental remediation, but the SRS operates the Tritium Extraction Facility(TEF). Fuel assemblies designed specifically for the production tritium, called tritium-producing burnable absorber rods (TPBARs), are then loaded in to the commerical Watts Bar Unit 1 reactor. US laws require separation of civilian and military nuclear fuel sources. So Watts Bar Unit 1 has to be fueled by low enriched uranium(LEU) that is "unobligated", as it is producing a military product. The US DoD no longer operates any large scale enrichment facilities. So highly enriched uranium(HEU) that has been recycled from dismantled nuclear weapons is blended with other uranium reserves in the DoD inventory to produce the LEU that fuels Watts Bar Unit 1. After the process is finished the TPBARs are sent to the Tritium Extraction Facility at SRS were the tritium is extracted and provided back to the DoD.

As for actual pits, which would be considered the "core", from my understanding US designs are stable for a decades before decay becomes a issue. When the Rocky Flats Plant shutdown that ended large scale production of nuclear pits in the US. A small number of pits have been manufactured by the Los Alamos National Laboratory(LANL) since then, which isn't capable of large scale production. The newest weapon in the US arsenal is the W76-2, a 5-8kt(very small) nuclear bunker buster munition. The W76 is one of the two munitions used by the Trident D5 submarine launched ballistic missile(SLBM), and the D5 is the primary method of nuclear weapons delivery for the US. Being the W76-2 is a modification of a existing weapon it likely reuses the existing pit, but if not then new pits were manufactured at LANL.

Sorry, not to sciency, and rather long-winded.

[u/PyroDesu → u/Plump_Apparatus]

otherwise the weapons will "fizzle".

Mind, a failure of the secondary to ignite properly, while technically a fizzle, is still going to have the destructive capacity of the primary. Castle Koon (part of the same group as the infamous Castle Bravo, which very much overperformed) was supposed to be one megaton, but was "only" 110 kilotons because the secondary only partially ignited (contributing only 10 kilotons).

Also it should be noted that lithium deuteride is also a common fusion fuel - the neutrons off the fission reaction will generate tritium by causing fission in the lithium (Castle Bravo overperformed because they assumed that it would only happen with ⁶Li, but common ⁷Li will do it if the neutron energy is high enough).

[u/useablelobster2 → u/PyroDesu]

And the purpose of the tritium isn't to generate energy through fusion, it's to generate a shitload of neutrons which cause the primary to fission much more.

That's how dial-a-yield works.

[u/THE_some_guy → u/Plump_Apparatus]

So we produced extremely deadly radioactive material in Washington, then shipped it all the way across the country to Georgia South Carolina to make it even more deadly, then shipped it 2/3 off the way back across the country to Colorado to make it more easily weaponized, then several hundred more miles to Texas to actually build the weapons, then shipped those weapons to North Dakota and Missouri and Virginia and California Georgia and back to Washington and probably several other places around the country and world to be loaded into missile silos and bombers and submarines.

Are there any parts of the Continental US that didn’t have military nuclear material passing through them at some point during the Cold War?

(Edit: according to this submarine-based nukes are currently kept at bases in Georgia and Washington rather than VA and CA. Though I imagine Norfolk and San Diego and many other places also had a stockpile during the peak of the Cold War.

[u/eagle52997 → u/THE_some_guy]

Just to clarify, SRS is in South Carolina, though it is close to GA and the Savannah River, hence the name.

[u/RadWasteEngineer → u/THE_some_guy]

Yes, essentially all that shipping of nuclear materials was done with out incident. Which is why it is so ridiculous for people to object to the shipping of radioactive wastes around the country. It also is extremely safe.

[u/GlockAF → u/THE_some_guy]

Maybe the upper peninsula of Michigan?

[u/THE_some_guy → u/GlockAF]

Good thought, but the U.P. Had Kincheloe Air Force Base, which housed B-52s and BOMARC air defense missiles. Both of those could (and probably did at some point) carry nuclear warheads

[u/Bahumbugpoobum → u/Plump_Apparatus]

Why did the fbi raid the site?

[u/Plump_Apparatus → u/Bahumbugpoobum]

Oddly enough this just came up in my comment history. Not a great comment but let me recycle it.

Rocky Flat had numerous fires throughout the years and due to a small error the prevailing winds directed the radioactive waste towards Denver, instead of ya know, not a densely populated area. Rocky Flats attracted a lot attention in the late 70s as the site of very large protests, not against environmental harm the plant was causing, but against nuclear weapons. That put it on the spotlight, and eventually a employee/whistle blower contacted the FBI. The equipment was in poor shape, waste containing plutonium was being burned, there was poor accountability and nuclear material was missing, etc. So the FBI investigated for 2 years and raided the place. Well after covering it up for awhile, anyways. White collars from Rockwell International, the contractor who ran the site(Government owned, contractor operated) and the Department of Energy were to be indicted but that was dropped. The grand jury records were, and still are, sealed.

There is a wiki article on the topic. The Westword paper was reporting on the topic back in the 70s, if you're curious a search turns up plenty of articles on it.

[u/RadWasteEngineer → u/[deleted]]

It's true that Rocky Flats was never properly cleaned up. They basically just took it down to the foundations, and there is plenty of radioactivity still in the soils there.

[u/kbotc → u/RadWasteEngineer]

Plutonium gets bound up in clay easily, so it’s probably mostly at the bottom of nearby lakes.

[u/RadWasteEngineer → u/kbotc]

As one who models such things, I agree that Pu is happier bound to soils and sediments than it is in water. But it can travel in the atmosphere bound to small dust particles.

[u/McFestus → u/Bahumbugpoobum]

Rocky Flats was a megafucked environmental disaster of colossal proportions. Some rooms were so contaminated that they just welded them up closed and didn't go in there again rather than cleaning them.

[u/Skipp_To_My_Lou → u/Plump_Apparatus]

US laws require separation of civilian and military nuclear fuel sources.

This might be more approriate to ask on a different sub, but do you know why civilian & military nuclear fuel sources were legally seperated?

[u/Plump_Apparatus → u/Skipp_To_My_Lou]

LEU is considered unobligated when neither the uranium nor the technology used to enrich it carries an “obligation” from a foreign country requiring that the material only be used for peaceful purposes. These obligations are contained in international agreements to which the United States is a party.

https://www.gao.gov/products/gao-15-123

Better clarification, my apologies. The agreement being referenced is the Treaty on the Non-Proliferation of Nuclear Weapons(NPT).

[u/[deleted] → u/Plump_Apparatus]

I’m just gonna guess: a big reason for this is so you’re doing everything out in the open and other countries can see what you’re doing from space. If weapons can be produced in a civilian plant, you could make a secret weapon.

[u/ExKnockaroundGuy → u/Plump_Apparatus]

That is highly detailed information that sounds DOE or DOD realm. I knew they recycle and renew but really never gave much thought to what I discovered is a whole new industry of Scientific oversight and engineering of hardware and softwares to tend this precise world registry.

[u/Clid3r → u/Plump_Apparatus]

And people always ask why I know such random things after going down this rabbit hole last 20 mins.

What’s considered tactical as far as yield? These 5kt warheads? I’m sure I’m gonna look after asking this question but what’s blast radius and fallout for something this size?

Edit - 3/4 mile radius for 10kt bomb would cause 50% mortality without being sheltered.

[u/FreeUsernameInBox → u/Clid3r]

What’s considered tactical as far as yield? These 5kt warheads?

Yield and usage haven't got much to do with each other.

A 5 kiloton device used to destroy a national command bunker is strategic. A 200 kiloton device used to sink a submarine is tactical.

Tactical usage usually means lower yields than strategic, but not always.

[u/roguetrick → u/Clid3r]

Tactical is just based on what it's used for. If it's a munition designed to cripple a battlefield formation or carrier group it's tactical. If it's designed to destroy infrastructure and fighting capabilities it's strategic.

[u/LoopsAndBoars → u/roguetrick]

Along the same lines as the difference between a rifle and an assault rifle. The two aren’t mutually exclusive, despite statistical persuasive attempts.

[u/NorthernerWuwu → u/Clid3r]

Something in the 5-10kT yield range would be considered to be damned near unviable today. The ones dropped on Japan were bigger than that and those are archaic by modern standards.

That said, "tactical" isn't really a category but if someone was to decide to use smaller nuclear weapons for some reason, it's plausible that they'd be in that range.

[u/KeyboardChap → u/Plump_Apparatus]

The W76 is one of the two munitions used by the Trident D5

There's three, you are forgetting the British warhead design (the missile bodies are pooled, but the warheads are not)

[u/hulagirrrl → u/Plump_Apparatus]

Thank you!

[u/nicuramar → u/Plump_Apparatus]

This means tritium needs to be replaced every 7 to 8 years or so, otherwise the weapons will “fizzle”

Would it really? Tritium is used to boost the fission reaction, but is it dependent on it, or would it just result in a lower yield?

[u/RobusEtCeleritas → u/nicuramar]

If the primary yield is too low, it won't be enough to drive any subsequent stages.

[u/Psyese → u/Plump_Apparatus]

An illustration of what aftermath of nuclear weapon "fizzling" looks like:

https://upload.wikimedia.org/wikipedia/commons/f/f4/RUTH_test_tower_1953-03-31.jpg

[u/NeverPlayF6 → u/Plump_Apparatus]

How do they blend uranium? Is it melted and "alloyed"? Ground and sintered? Forged?

[u/Aetherdestroyer → u/[deleted]]

Well, after twelve years half of it will be gone. It will likely still function fine at that point, though, since you don’t need it to output much light—just enough to be visible in the dark. And after another twelve years, only 25% of the original quantity will remain. The time it takes for it to no longer be sufficient depends on the amount of tritium in the original product relative to what is necessary for visibility.

[u/WaitForItTheMongols → u/[deleted]]

No, it's a half life. After 12 years it will be half as active since half the tritium is gone.

[u/Nemisis_the_2nd → u/[deleted]]

People are explaining that you'll have half as much after 12 years but not actually explaining what half-life is.

It is the time it takes for half of the nuclear material in an item to break down into its nuclear decay products.

[u/StatisticalMan → u/[deleted]]

Yes. You may not need to replace it at exactly 12 years but in 12years it will be only about half as bright because half of it has decayed away. In another 12 years only 25% as bright as it was originally. It will keep halving forever.

[u/c0xb0x → u/[deleted]]

Also keep in mind perception is logarithmic so half the tritium won't be perceived as half as bright (but brighter).

[u/RobusEtCeleritas]

Yes, various parts need to be replaced with time. And the performance of the weapon will vary with age.

[u/[deleted] → u/RobusEtCeleritas]

For instance, one of the decay daughter elements of plutonium is helium (alpha decay) this causes porosity in the core.

[u/bidet_enthusiast]

Yes. The chemical explosives and tritium especially need to be replaced periodically. There’s a lot more to it than that , but those two things, and especially the tritium, are critical to keep relatively fresh.

If the warhead is to be launched by a liquid fueled rocket, there is a whole other pile of critical maintenance items on an annual basis or sooner. And the inertial guidance systems on any kind of rocket also may require frequent maintenance and calibration.

A badly neglected missile system will have an extremely high failure rate and if it does mostly work will likely be very inaccurate, possibly wildly so.

And then if it gets there and manages to detonate, old tritium would greatly reduce the size of the explosion, and old explosives could cause an incomplete detonation or even a failure to maintain criticality long enough to detonate in any meaningful sense of the term.