> they could have an arsenal that’s functional as a deterrent in months, if not weeks

Japan is what's called a threshold/latent nuclear power. These are countries with the ability to build nuclear weapons immediately, but haven't turned the switch yet.

Taiwan, Iran, Canada, Germany, Netherlands, Brazil, Mexico, and South Korea are other threshold powers, and Saudi and the UAE are pressing for plutonium enrichment capabilities in the next few years as well.

Generally speaking, a country with a space program and a civilian fuel enrichment program can be safely assumed to be a latent nuclear power.

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

The Wikipedia article didn't have any info on ramp time.

My understanding is it requires building enrichment facilitates, and processing materials. Is this not a multi-year effort?

Japan has already separated large quantities of reactor grade plutonium:

https://world-nuclear.org/focus/fukushima-daiichi-accident/j...

At the end of 2018 there was 9 tonnes of separated reactor-grade plutonium (about 66% fissile) stored domestically, plus a total of 36.6 t in the UK and France. That total of 45.6 t was a modest decrease from an estimated 47.3 t at the end of 2017.

Despite the name, "weapons grade plutonium" is not actually required to make a weapon. Japan could manufacture weapons of modest yield (comparable to those used against it in World War II) on a short timeline from reactor grade plutonium if it were willing to ignore the political reaction.

See this for a relatively brief technical explanation of using reactor-grade plutonium in weapons: "Reactor-Grade Plutonium Can be Used to Make Powerful and Reliable Nuclear Weapons" https://rlg.fas.org/980826-pu.htm

This is a much longer book discussion (PDF) of the same issue: "Reactor-Grade Plutonium and Weapons: Exploding The Myths" https://npolicy.org/wp-content/uploads/2021/06/Reactor-Grade...

> Is this not a multi-year effort

If you have a strong civilian nuclear power program, the ramp up time is minimal (weeks to months), as fast breeder reactors are a dual use technology.

If the country also has a domestic space program, you can safely assume they are also working on building IRBM capabilities

I was originally gonna say that FBRs are in many places phased out (I think Japan's last one shut down in 2017) but if I'm reading right a BWR can work in a pinch, so there's -that-...

My guess with minimal knowledge in the field is, weeks if they have a shut down FBR plant, months if they have a decommed FBR Plant. I feel like building a new one to 'ramp up' would either require more time or perhaps multiple smaller reactor projects working in parallel might do the job...

Japan is restarting it's FBR program [0]

In all honesty, it feels like everyone's arming for something big - from UAE all the way to the US and China, every country is in the process of buying startups and firms working on dual use technology.

Every country seems to have some sort of a 5-10 year roadmap to modernize defense technology and logistics by 2035, yet I never saw this level of concentrated effort globally after 1989.

[0] - https://asia.nikkei.com/Business/Energy/Japan-nuclear-resear...

Side note: always appreciate (and look for) your comments in these threads.

No prob! That means a lot coming from you!!!

That said, I sincerely hope my prediction is just paranoia and that I'm wrong.

It's UAE and Saudi's deal flow that got me worried recently. I'm seeing those guys everywhere in the defense tech space now, and if Saudi and UAE are stockpiling, then every other semi-competent regional power is as well.

Saudi Arabia might have had access to nuclear weapons for a while, as part of an arrangement with Pakistan.

https://www.bbc.com/news/world-middle-east-24823846

https://en.wikipedia.org/wiki/Saudi_Arabia_and_weapons_of_ma...

It's a gentleman's agreement before Imran Khan entered the political arena.

Imran Khan leaned pro-Qatar, which irked KSA, especially because IK turned down joining Saudi's coalition in Yemen.

It was around this time that KSA began charting it's own independent course, just like UAE.

In Japan’s case, depending on what you mean they’ve already got IRBM (indeed, ICBM) capabilities. Their space industry has been building capable solid fuel boosters for a couple of decades.

I assume they haven’t actually tested a precision guided reentry vehicle, but that’s all they’re missing on the missile side.

There's one in Rokkasho-mura in Aomori, ~20mi from USFJ/JSDF Misawa AB. Not officially complete, whatever that's supposed to mean.

My limited understanding was that one of the core technologies needed to build a nuclear bomb is the explosion lens that uses conventional explosives to put pressure on the nuclear material. And this technology is not something that is involved in space program or using nuclear power peacefully.

Is it really that obvious to develop now?

See the W88 saga from the 90s. I expect this is now very well understood stuff.

Saudi Arabia might already have access to nuclear weapons earmarked by Pakistan, as part of an agreement, when Saudi Arabia helped fund Pakistan's nuclear program.

https://www.bbc.com/news/world-middle-east-24823846

https://en.wikipedia.org/wiki/Saudi_Arabia_and_weapons_of_ma...

Do you know what might push them to go ahead with this? The first post-ww2 use of one in battle?

Nothing has to push them. These countries want to go nuclear. The only thing preventing them is the threat of american intervention. Japan and South Korea had secret nuclear programs that we put a stop to. Canada, Brazil and Mexico will never be allowed to own nukes. No nation in the western hemisphere will allowed to own nukes outside the US. As for germany and the netherlands, we'd sanction and isolate them if they ever developed nukes. They could have nukes, but their economy would be in shambles like north korea. If taiwan went nuclear then it would be the end of taiwan and both the US and china would take them out.

That makes sense, so I guess once Ukraine loses, it'll make more sense for them to push the button and get ready. Better to be hungry and free than ending up in Siberia.

The french Force de frappe would like to have a word with you...

Also UK, even if they've outsourced production and maintenance of them to the US, or something like that.

I'm also liking the idea of the mexican cartels having their own nukes.

Hrrm. Lemme sniff some more cocaine...(snort)

Waht to target? Hrrm...You'll see, tee hee hee!

It was a security measure. Properly guarding enriched plutonium is not to take lightly.

There's a trick to it though...

https://www.nytimes.com/2022/02/05/science/ukraine-nuclear-w...

There are many legends about fissile material, or even “bomb kits” hidden away in some of Sweden’s many hollow mountains.

According to Wilhelm Agrell’s book “Svenska förintelsevapen”, the foundation for one such legend is as follows: There was a chunk of plutonium in a lab somewhere, acquired from the UK, I think. When the nuke program was ramped down, it was decided that this chunk should be transferred to a certain laboratory in Norway. However, getting the bureaucratic stars aligned to do this “by the book” turned out to be a major headache, to the point that some exasperated manager eventually packed the stuff in his briefcase, drove to Norway in his own car and handed it over personally, thus breaking every rule in the book and a few not yet written, but at least getting rid of the cumbersome thing from his lab!

It's a lot easier to get the paperwork signed when the event has already happened.