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United States discloses nuclear warhead numbers; restores nuclear transparency

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Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#3
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

https://www.youtube.com/watch?v=N2OUzBrLEFk is a interesting video about the transport of these weapons

Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#4
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

Plutonium pits slowly transmute, and the emitted alpha particles are trapped and form helium bubbles. They have to be replaced periodically.

Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#5
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

> how long a nuke in storage lasts

Decades, certainly. All but the first few generations of bombs were designed for long periods of storage.

Notably, many of the TOP500 supercomputers were built with the singular goal of simulating the ageing of nuclear weapons in storage.

If a supercomputer is owned by the DoE or SANDIA, then that's what it is for.

> turn those swords into ploughshares relatively easily.

Yes! Cold-war era warheads from both the Soviet Union and the US have been used as nuclear fuel. A notable one was the Megatons to Megawatts program: https://en.wikipedia.org/wiki/Megatons_to_Megawatts_Program

The plutonium in bombs is essentially "super high grade" reactor fuel. Even degraded after decades in storage it is still far, far better than what is typically used. It just needs to be converted into the MOX (metal oxide) fuel pellets and then used in a reactor, pretty much as-is.

Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#7
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

It takes quite a bit of work to maintain nuclear warheads. All active US weapons contain plutonium 239, which has a half life of 24,100 years. It's radioactive by alpha decay, which leads to changes in the material properties due to energetic collisions and the buildup of microscopic helium bubbles (alpha particles are merely ionized helium nuclei, so stopped alpha particles become helium). Since the US stopped testing actual nuclear warheads in the early 1990s, it takes a great deal of indirect theoretical and experimental evidence to make sure that nuclear warheads are reliable without live fire tests. That's part of "stockpile stewardship." [1] If the plutonium has deviated too far from its original mechanical behavior, it would need to be removed from warheads, purified, and remanufactured into replacements that match the original specs. And again, the rebuilt components need to be reliable but they can't actually be tested via explosion.

US weapons also rely on tritium gas "boosting" to operate reliably and efficiently [2], and tritium decays with only a 12.3 year half life. The gas reservoirs of weapons need their tritium replaced at significantly shorter intervals. Even manufacturing enough tritium to maintain the stockpile has become a challenge because the US has retired its Cold War era weapons-material reactors that used to operate at Hanford and Savannah River. Currently the US uses a power reactor owned by the Tennessee Valley Authority to make tritium for weapons [3].

It's possible to make nuclear weapons (even thermonuclear weapons) with only uranium 235 for fissile material and no stored tritium. Such weapons could last a much longer time without active maintenance, since U-235 decays thousands of times slower than Pu-239. However, they would be larger and heavier for the same explosive yield, which complicates delivery. They would also lose certain safety features. Finally, without being able to perform full scale tests, it is doubtful that the US would have the confidence to replace its current high-maintenance weapons stockpile with a new generation of low-maintenance weapons.

[1] https://en.wikipedia.org/wiki/Stockpile_stewardship

[2] https://nuclearweaponarchive.org/Nwfaq/Nfaq4-3.html#Nfaq4.3....

[3] https://www.wvlt.tv/2022/05/24/watts-bar-lone-source-nuclear... "Watts Bar lone source of a nuclear weapon material; TVA increasing production"

Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#8
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

Plutonium pits slowly transmute, and the emitted alpha particles are trapped and form helium bubbles. They have to be replaced periodically.

I think the tritium "preignition" has to be replaced every 10 years.

Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#9
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

I think it’s shorter than you would imagine. I recall an episode of the podcast Arms Control Wonk talking about the nukes in possession of Ukraine during the collapse of the Soviet Union. Professor Lewis stated that those warheads likely had a service life of 5-10 years. But that may be specific to those Soviet warheads, and I think that different components need to be replaced at different intervals.

Re: United States discloses nuclear warhead numbers; restores nuclear transparency

#10
post #2

Max warheads = 31k Current warheads = 3.7k I wonder how long a nuke in storage lasts - ie, how much work does it take to maintain a stockpile of x nukes, and if you can turn those swords into ploughshares relatively easily.

It takes quite a bit of work to maintain nuclear warheads. All active US weapons contain plutonium 239, which has a half life of 24,100 years. It's radioactive by alpha decay, which leads to changes in the material properties due to energetic collisions and the buildup of microscopic helium bubbles (alpha particles are merely ionized helium nuclei, so stopped alpha particles become helium). Since the US stopped testi…

How do you know all this? Is that a hobby or a job?
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