Nuclear Production Hypothetical Question

So, looking at nuclear arsenal build ups around the world the production numbers seem all over the place. Some nations took decades to piece it together. The Americans apparently had thousands in the late 50s on the other hand, while the Soviets lagged.

So, here's my question: Let's say a two nations are waging an Eastern Front scale of warfare. The tech level is 50s level. The side on the offensive has production levels something along the lines of the USSR (maybe a bit higher). The defenders have bit less than the US to start, and the war's thrown them for a loop. So, I'm wondering how many nukes the two could build up while fighting a massive scaled war? They've both got plenty of uranium, and there's a fair amount of room for testing. The attackers have their industrial centres a fair distance from the front, while the losing side has their heartland on the edge of the front (so bombing is a fairly straightforward thing for the attackers).
 

Delta Force

Banned
Uranium bombs are inefficient to build, especially with the technology available at the time. They should build a gas cooled (carbon dioxide would do nicely) graphite moderated nuclear reactor or a heavy water cooled/moderated nuclear reactor in order to acquire plutonium, then reprocess their spent fuel to build implosion bombs. It should be a pile type reactor so the fuel is continuously produced.
 
Uranium bombs are inefficient to build, especially with the technology available at the time. They should build a gas cooled (carbon dioxide would do nicely) graphite moderated nuclear reactor or a heavy water cooled/moderated nuclear reactor in order to acquire plutonium, then reprocess their spent fuel to build implosion bombs. It should be a pile type reactor so the fuel is continuously produced.

Well I didn't know the specifics of production, but those still need uranium no?
 

Delta Force

Banned
Well I didn't know the specifics of production, but those still need uranium no?

Gas and heavy water cooled reactors have high enough neutronic efficiency that you can use natural uranium and don't have to do any enrichment to make it function in the reactor. That makes them good for producing tritium gas for thermonuclear weapons when that point is reached, although there is a tradeoff between plutonium production and tritium production.

If you use light water reactors, you have to enrich the uranium to make it function. That's quite troublesome with gaseous diffusion technology, which was the standard of the time. For example, Eurodif, the European uranium enrichment facility built in the 1970s, had three nuclear reactors at a four reactor complex assigned to meet its electricity requirements. They were large power reactors too. Even less efficient solutions were perused during the Manhattan Project.

Centrifuges might be possible in the 1950s, and the Japanese were working on an ultra-centrifuge towards the end of World War II for their nuclear program. However, there presumably must be some reason why the French chose to use gaseous diffusion instead of centrifuges. Centrifuges seem to be more a 1980s and later technology.
 
Gas and heavy water cooled reactors have high enough neutronic efficiency that you can use natural uranium and don't have to do any enrichment to make it function in the reactor. That makes them good for producing tritium gas for thermonuclear weapons when that point is reached, although there is a tradeoff between plutonium production and tritium production.

If you use light water reactors, you have to enrich the uranium to make it function. That's quite troublesome with gaseous diffusion technology, which was the standard of the time. For example, Eurodif, the European uranium enrichment facility built in the 1970s, had three nuclear reactors at a four reactor complex assigned to meet its electricity requirements. They were large power reactors too. Even less efficient solutions were perused during the Manhattan Project.

Centrifuges might be possible in the 1950s, and the Japanese were working on an ultra-centrifuge towards the end of World War II for their nuclear program. However, there presumably must be some reason why the French chose to use gaseous diffusion instead of centrifuges. Centrifuges seem to be more a 1980s and later technology.

Well, locked in a massive conventional war they'll probably not have time for working out the perfect method. Expect it a bit less efficient than OTL was managing with the same tech level.
 

Delta Force

Banned
Well, locked in a massive conventional war they'll probably not have time for working out the perfect method. Expect it a bit less efficient than OTL was managing with the same tech level.

There's a reason why those were the favored approaches. Heavy water was known to have potential from the early nuclear experiments pre-dating the atomic bomb. Gas was also known to have potential, but the Manhattan Project probably went with heavy water because it could use existing knowledge of water boilers. The Manhattan Project also experimented with gas cooled reactors, although they were air cooled, not carbon dioxide cooled as with the British and French designs. Air cooling posed severe safety issues due to the corrosive nature of high temperature air and the fire potential. The fire safety risks are best illustrated by the Windscale Fire, which could have been very bad for the United Kingdom if Sir John Cockcroft hadn't insisted on installing exhaust filters (Cockcroft's Follies, because they were thought to be expensive additions that were overly cautious) on the reactor, which caught most of the radiation during the incident.

The British and French chose to use the gas approach for their nuclear weapon programs (and presumably the DPRK as well) because using gas means one less rare material is needed. Also, you typically want to use hydropower to produce heavy water, so if you don't have a large facility it becomes less feasible.
 
There's a reason why those were the favored approaches. Heavy water was known to have potential from the early nuclear experiments pre-dating the atomic bomb. Gas was also known to have potential, but the Manhattan Project probably went with heavy water because it could use existing knowledge of water boilers. The Manhattan Project also experimented with gas cooled reactors, although they were air cooled, not carbon dioxide cooled as with the British and French designs. Air cooling posed severe safety issues due to the corrosive nature of high temperature air and the fire potential. The fire safety risks are best illustrated by the Windscale Fire, which could have been very bad for the United Kingdom if Sir John Cockcroft hadn't insisted on installing exhaust filters (Cockcroft's Follies, because they were thought to be expensive additions that were overly cautious) on the reactor, which caught most of the radiation during the incident.

The British and French chose to use the gas approach for their nuclear weapon programs (and presumably the DPRK as well) because using gas means one less rare material is needed. Also, you typically want to use hydropower to produce heavy water, so if you don't have a large facility it becomes less feasible.

Well what sort of production would they get? A few dozen a month? One or two a month?
 

Delta Force

Banned
I found something better. Information from this book, paraphrased.

Magnox produced 1 gram of plutonium for every 1 megawatt of thermal output. A 500 megawatt electrical capacity (approximately 1500 megawatt thermal) Magnox reactor would be expected to produce 1,500 grams of plutonium per day, around 450 kilograms per year if it produces for 300 days per year. This formula tends to apply for most other reactors running on natural uranium, which would include other gas and heavy water cooled designs.

Later power reactors (presumably light water reactor and other designs running on enriched uranium) can be expected to produce 0.5 grams of plutonium for every 1 megawatt of thermal output.

Also, a natural uranium reactor produces 70% to 80% pu-239, while a later power reactor (presumably light water reactor and other designs running on enriched uranium) produces 50% to 60% pu-239. The other plutonium will lead to premature detonation or pose a danger to people extracting the material, complicating reprocessing.

As a final note, natural uranium designs need ten times as much uranium to go critical as a reactor using enriched fuel, but of course it's easier to acquire natural uranium than enriched uranium.
 
Making a natural uranium reactor is scarily simple: Chicago Pile 1 was a pile (in the literal sense) of graphite with holes for natural uranium elements.

The ony requirements for the job are: gobs of graphite with low content of neutron absorber elements, gobs of uranium without neutron poisons and a definite lack of common sense.

Let the thing cook, extract the uranium fuel elements, have them cool (to kill short life radionuclides) and chemically separate plutonium. Rinse and repeat.

The nazis did try the graphite road first and we have to be thankful that the material they used contained too much boron impurities to work. Had it been purer (like american graphite) they would have been able to build their pile, they would have gotten hard data about neutron cross sections and therefore they could have revised appropriately their bomb core size estimates.
 
I found something better. Information from this book, paraphrased.

Magnox produced 1 gram of plutonium for every 1 megawatt of thermal output. A 500 megawatt electrical capacity (approximately 1500 megawatt thermal) Magnox reactor would be expected to produce 1,500 grams of plutonium per day, around 450 kilograms per year if it produces for 300 days per year. This formula tends to apply for most other reactors running on natural uranium, which would include other gas and heavy water cooled designs.

Later power reactors (presumably light water reactor and other designs running on enriched uranium) can be expected to produce 0.5 grams of plutonium for every 1 megawatt of thermal output.

Also, a natural uranium reactor produces 70% to 80% pu-239, while a later power reactor (presumably light water reactor and other designs running on enriched uranium) produces 50% to 60% pu-239. The other plutonium will lead to premature detonation or pose a danger to people extracting the material, complicating reprocessing.

As a final note, natural uranium designs need ten times as much uranium to go critical as a reactor using enriched fuel, but of course it's easier to acquire natural uranium than enriched uranium.

I'm guessing that those reactors would need a lot of concrete? That seems like something that would be in high demand on the war front, so that will probably delay things.

Still, that's a lot of plutonium per year.

Also, Little Boy used uranium, would that be easier for mass production?
 
Also, Little Boy used uranium, would that be easier for mass production?

AFAIK no way. U-235 is just 0,72% of regular uranium ore. Also, but I am not sure exactly, but I think they needed like tons of pitchblende to extract like kilograms of uranium and then tons of uranium to extract kilograms of -235 isotope.
 

Delta Force

Banned
I'm guessing that those reactors would need a lot of concrete? That seems like something that would be in high demand on the war front, so that will probably delay things.

All of that really depends on how much safety is desired. Containment systems don't really add to the function of the reactor, for example. The need for precision metal parts is probably a greater bottleneck. However, a reactor can use metal tubes instead of a pressure vessel, and some reactors such as the later Magnox designs had concrete pressure vessels instead or metal ones. They are actually safer and less expensive relative to metal pressure vessels, in addition to being easier to fabricate.

Still, that's a lot of plutonium per year.

Also, Little Boy used uranium, would that be easier for mass production?

Plutonium is much easier to produce in large quantities. It also has a smaller critical mass relative to uranium designs.
 
All of that really depends on how much safety is desired. Containment systems don't really add to the function of the reactor, for example. The need for precision metal parts is probably a greater bottleneck. However, a reactor can use metal tubes instead of a pressure vessel, and some reactors such as the later Magnox designs had concrete pressure vessels instead or metal ones. They are actually safer and less expensive relative to metal pressure vessels, in addition to being easier to fabricate.

Okay, so if they're tossing things up in Ungava or Tunguska or something they've got room to cut corners on safety?

I guess they can both toss together a few dozen nukes over the first two years of war.
 

Delta Force

Banned
Hanford B used a 30 mile long road as its safety system. From Wikipedia (on Windscale, but it was similar to B Reactor):

The design initially called for the core to be cooled like the B Reactor, which used a constant supply of water that poured through the channels in the graphite. There was considerable concern that such a system was subject to catastrophic failure in the event of a loss-of-coolant accident. This would cause the reactor to run out of control in seconds, potentially exploding. At Hanford, this possibility was dealt with by constructing a 30 miles (48 km) escape road to evacuate the staff were this to occur, abandoning the site.[8] Lacking any location where a 30 mile area could be abandoned if a similar event to occur in the UK, the designers desired a passively safe cooling system. In place of water, they used air cooling driven by convection through a 400 feet (120 m) tall chimney, which could create enough airflow to cool the reactor under normal operating conditions. The chimney was arranged so it pulled air through the channels in the core, cooling the fuel via fins on the cartridges. For additional cooling, huge fans were positioned in front of the core, which could greatly increase the airflow rate.

It can be even less expensive without a filter. The Follies greatly increased the price of Windscale, but no one was calling them that when they captured over 90% of the radiation released during the fire (the worst power reactor incident until Chernobyl, and third worst in history after Chernobyl and Fukushima):

During construction, Terence Price, one of the many physicists working on the project, began to consider what would happen if one of the fuel cartridges being pushed out the back of the core were to break open. This could happen, for example, if a new cartridge being inserted was pushed too hard, causing the one at the back of the channel to fall past the relatively narrow water channel and strike the floor behind it. In that event, the hot uranium could catch fire, with the fine uranium oxide dust being blown up the chimney to escape.[10] When he raised the issue at a meeting and suggested that filters be added to the chimneys, the concern was dismissed as being too difficult to deal with and was not even recorded in the minutes. Sir John Cockcroft was alarmed enough to order that filters be installed, which required them to be constructed on the ground while the chimneys were still being built, and then winched into position at the top once the chimney's concrete had set.[11] These became known as "Cockcroft's Folly" by workers and engineers.
 
some reactors such as the later Magnox designs had concrete pressure vessels instead or metal ones. They are actually safer and less expensive relative to metal pressure vessels, in addition to being easier to fabricate.

Why are so many pressure vessels built out of steel then?

And am I correct in my belief that most nuclear power plants use steel pressure vessels?

The nazis did try the graphite road first and we have to be thankful that the material they used contained too much boron impurities to work. Had it been purer (like american graphite) they would have been able to build their pile, they would have gotten hard data about neutron cross sections and therefore they could have revised appropriately their bomb core size estimates.

ObWI: German industry is able to produce higher-purity graphite for the Nazi bomb project. What changes?

fasquardon
 

Delta Force

Banned
Why are so many pressure vessels built out of steel then?

It's because most nuclear reactors are water cooled and operate at higher pressures. Gas cooled reactors operate at lower pressures more suitable for reinforced concrete. The reinforced concrete pressure vessel was mostly a British development for their gas cooled reactors, although the Process Inherent Ultimate Safety reactor was a light water reactor that would have used reinforced concrete as well.

And am I correct in my belief that most nuclear power plants use steel pressure vessels?
The vast majority of nuclear reactors use steel pressure vessels, and the vast majority of nuclear reactors are light water reactors. The most successful alternative to the light water reactors are the heavy water reactors, followed by gas cooled reactors (mostly represented by a handful of British and French reactors), and then a very limited number of sodium cooled reactors. They all use metal pressure vessels, except for some of the British gas cooled reactors.
 
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