The Japanese nuclear weapons program

Discussions on all aspects of the Japanese Empire, from the capture of Taiwan until the end of the Second World War.
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williamjpellas
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Re: The Japanese nuclear weapons program

Post by williamjpellas » 14 Mar 2015 16:51

steverodgers801 wrote:So someone says Japan tried, I would like to know where it was, how many men and such?
Documents have come to light indicating for the first time that Japanese scienists were at work in World War II on an atomic bomb for use against this country but were thwarted by air raids, lack of official coordination and funds, and the backwardness of atomic physics in Japan.
http://select.nytimes.com/gst/abstract. ... 5B888BF1D3
you have to buy the article which I may, buy it repeats what I essentially said. There was one scientist working of the theory. Trying does not indicate any level of success.

Again, Steve, your assertions here are just silly and plainly demonstrate that you've done little to no reading on the subject whatsoever. In 1941, Bunsaku Arakatsu, Einstein’s former student (between the world wars, when both were in Gemany) and future head of the F-Go Japanese Navy a-bomb project, published two papers in conjunction with several other first-rate Japanese scientists, most of whom eventually worked with him on the Japanese bomb. Arakatsu and his co-authors published their writings in the journal, Proceedings of the Physical and Mathematical Society of Japan, #23. These papers were titled, “Photo-Fission of Uranium and Thorium Produced by the 7-rays of Lithium and Flourine Bombarded With High-Speed Protons” and “Range of the Photo-Fission Fragments of Uranium Produced by the 7-ray of Lithium Bombarded with Protons". This is not very "backward" atomic science, and the potential application of work like this to nuclear weapons physics is obvious.


http://www.alwaysresearching.com/2013/0 ... aphy-1946/


PS The New York Slimes is the very last place I would ever look if I were trying to find out much of anything about anything, but particularly when it comes to information that might run counter to the arch-anti-American deconstructionism and Marxism so plainly being promoted by that rag.
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Genro
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Re: The Japanese nuclear weapons program

Post by Genro » 14 Mar 2015 17:41

Some notes on the Osaka University Uranium Isotope separator.

Shuji Fufui has written in Japanese some 30 or 40 years after the event on this topic.
I have glanced through them and full translations would be a long and tedious task, so I can only give a superficial rendering.

The Clusius-Dickel column consisted of three 4.91 metre tube joined together and with a gap of 2mm between the inner and outer tubes. Before Uranium Hexafluoride is introduced the space has to be evacuated. This proved to be difficult to achieve and Nishina was called to Osaka and reckoned the problem lay with the welds.
The next problem was that of maintaining the gap when the central column was heated up and also ensuring it was truly vertical.
It was also found that the amount of Uranium Hexafluoride injected into the column was greater than the column could theoretically take. This was due to the formation of a bi-fluoride layer that inhibited further chemical attack. Now days such equipment is flushed with chorine trifluoride to ‘pickle’ the metal surfaces prior to admitting the Uranium hexafluoride.
As Osaka University had no working cyclotron they were asked to develop a Nier-type mass spectrometer to determine the separation. Nishina converted the enriched sample to UO3 and with a natural sample irradiated them both with thermal neutron using a moderator and the cyclotron.
Either the spectrometer did not have the resolution or if it did, then no separation occurred .Either way the project was unsuccessful.
Ignoring the dead space that must have existed at the top and bottom of the column and assuming a best separation factor of 1.004, the best that might have been achieved would be about 1.2% U235.

On 13th March 45 Osaka was heavily bombed and though the University escaped destruction they were now without electricity, gas or water.

On 14th April Riken was destroyed with the exception of the large cyclotron.
No.49 building housing the two diffusion towers was completely demolished.

15th August the Clusius-Dickel equipment was thrown into the Tosabori river from the Chikuzen bridge.

I emphasise again that this is only a superficial reading and a full translation will have to wait another time.

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 14 Mar 2015 18:55

The Manhattan Project, which also employed thermal diffusion at its S-50 plant, decided to use the slightly-enriched product from that facility as the first step in the process of making actual HEU. According to what I have read, the American S-50 plant was only able to achieve enrichment of around 2%. I would imagine that the percentage could ultimately have been increased simply by repeating the process as many times as necessary (whether by passing the product through the loop again or by passing it on to another thermal diffusion factory), but the Manhattan Project decided to take the S-50 output and use it as feedstock for the gaseous diffusion plant. The output from that plant, in turn, was sent on to the "Calutrons"---electromagnetic separators---for completion.

http://en.wikipedia.org/wiki/S-50_(Manhattan_Project)

By the way, both the Wikipedia article I just posted and others I skimmed indicate that the S-50 plant used liquid thermal diffusion, as opposed to the gaseous thermal diffusion of the Japanese project. I thought that only gaseous thermal diffusion was possible in WWII? Perhaps some others can shed some light on this point.
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Takao
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Re: The Japanese nuclear weapons program

Post by Takao » 15 Mar 2015 04:28

The S-50 plant was producing as of October, 1944, but did not hit it's stride until February, 1945.
http://www.osti.gov/includes/opennet/in ... 0Secre.pdf

Unfortunately, this is the only document available on from Book VI on Liquid Thermal diffusion.
Main site: https://www.osti.gov/opennet/manhattan_district.jsp

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Re: The Japanese nuclear weapons program

Post by Genro » 15 Mar 2015 11:29

S-50 enrichment 0.85% U235.

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 15 Mar 2015 12:51

Genro wrote:S-50 enrichment 0.85% U235.
In the Wikipedia article above, it is said that the output of the S-50 thermal diffusion plant was initially just .85 percent enriched. This was in January, 1945. Later, the figure of "less than 2 percent" is given. Apparently the percentage of enrichment, while still obviously low, was improved by the elimination of leaks that had compromised the operation of the plant when it first came online beginning in September 1944. Per the original, period document posted by Takao, S-50 did, indeed, employ liquid thermal diffusion, while Nishina was using gaseous thermal diffusion. Interesting. According to the Tonizo Reports posted by Genro, Nishina's machinery achieved 10% enrichment, though S-50's output was obviously in much greater amounts (about 28 tons through September 1945) than Riken's sample or laboratory quantities.

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Re: The Japanese nuclear weapons program

Post by Genro » 15 Mar 2015 14:15

With the exception of electro magnetic isolation, all processes relying on mass differences for separation have an ultimate equilibrium separation factor. The very act of withdrawing material from the separator degrades this factor whether it be gas/liquid or centrifuge. The product of enrichment and quantity is essentially a constant.

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 15 Mar 2015 17:40

Genro wrote:With the exception of electro magnetic isolation, all processes relying on mass differences for separation have an ultimate equilibrium separation factor. The very act of withdrawing material from the separator degrades this factor whether it be gas/liquid or centrifuge. The product of enrichment and quantity is essentially a constant.
Which in non-wonkspeak presumably means, "Every time you pass the feedstock through the separator, "X" percent separation / enrichment occurs. Thus for Nishina's 10% enrichment figure to have been accurate, he must have passed the same material through his separator(s) a number of times".

Okay, whatever. Your document , so you say, indicates Nishina's claim that he achieved 10%. Or at least, the translation of the document (the Kuroda Papers) that you are posting here and that is presumably accurate, indicates this claim. Alright, fair enough, but you then followed that up by repeating something about how we should beware of novelists. I don't have any idea at all what "novelists" have to do with 1) the source for your figure of 10%, and 2) whether that figure and the translation from which it comes are reliable, or not. It would help if you would just state plainly what you are saying and what you are trying to "prove" instead of throwing out a bunch of technical-ese and then periodically peeking out from amongst the weeds to throw some snark into the discussion. Thanks.

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 15 Mar 2015 18:53

Speaking of which, I am not, myself, "trying to prove" that Japan really did succeed in building at least one functioning atomic bomb in some configuration and then setting it off in a bay on the coast of what is today North Korea. I am trying to find out what proof there is---or is not---that that event actually occurred. Obviously I strongly favor the conclusion that they did succeed, but I am not wedded to it PROVIDED sufficient proof can be offered to support the opposite conclusion (that they did not succeed). It seems to me beyond a reasonable doubt that there is more than sufficient documentation to prove that Japan was, in fact, pursuing nuclear weapons during WWII, that they made considerable progress, both theoretical and industrial, toward those weapons, and that they received some help in some form from the Germans.


I have already stated, publicly and for the record and under my own name, that if your translations and your interpretation of them are correct, then I was mistaken in my assertion that the Kuroda Papers contained a working bomb design, as such. (I am here referring to my previously published article on this subject, "The Japanese Bomb and Why It Matters".) I would say, however, that this is a distinction that has more to do with degree than of kind. Meaning, obviously Nishina had in mind a gun-type U-235 atomic fission bomb, same as the US Little Boy device built at Oak Ridge, TN, and clearly the Japanese were working diligently toward such a bomb. The question is the degree to which they made progress, not the kind of progress they were hoping to achieve. Was there sufficient information in the Kuroda Papers, and was it sufficiently accurate, for the Japanese to have attempted to assemble a U-235 gun type atomic fission bomb, or not? You say no, though the translations you provide, if reliable, certainly show very advanced nuclear weapons physics, and here again, I must point out that of all the warring powers, Japan has been the least forthcoming about its atomic projects. Even the Russians have been more open than the Japanese, amazingly. Which means that the Kuroda Papers are by no means the only, much less the complete, accounting of the Japanese work in the field during the war itself. We know much less about the Navy's Project F-Go and next to nothing about F-NZ in Korea. It has come to my attention recently that there was probably a third center of gravity for the Japanese atomic work, in addition to the Riken Institute (Army Project Ni) and Kyoto Imperial University (Navy Project F-Go and related research into atomic power for propulsion) but I cannot discuss it in detail at this time.


In other words, once again and contrary to what I believe to be a considerable distortion in many of the "histories" that emerged about the end of WWII particularly from the mid-1960s forward, Japan---like all of the major warring powers---was trying to build atomic bombs to win the war. She simply lost the race to make them. She was emphatically not any kind of victim of some nefarious imperialist agenda on the part of the US and the Allies. Period.


From here it is mostly a matter of historical detective work to answer the questions of what documentation can be catalogued and what conclusion(s) can be reasonably drawn from that documentation.

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Re: The Japanese nuclear weapons program

Post by Genro » 15 Mar 2015 20:21

“ I would really like to see a bomb physicist do a calculation----“ 18 Dec 2003 04:02
Who wrote that ?

With out at least some comprehension of science this sort of rubbish gets printed and believed by many.

‘Gauges at the top and bottom of the column, intended to measure a difference in pressure - showing that separation was taking place - indicated no difference at all.’
The Making of the Atomic Bomb. Richard Rhodes.

The less said about Wilcox’s books the better they are considered a joke in physics.

Here is a thought, if Japan had had the industrial and financial muscle that America had at the time, the atomic bomb would probably have been made in half the time and at half the cost and with the need of brains from Europe.

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Re: The Japanese nuclear weapons program

Post by steverodgers801 » 15 Mar 2015 21:52

this is Wiki, but: The Army was not discouraged, and soon after the Committee issued its report it set up an experimental project at Riken, the Ni-Go Project. Its aim was to separate uranium-235 by thermal diffusion, ignoring alternative methods such as electromagnetic separation, gaseous diffusion, and centrifugal separation. By February 1945, a small group of scientists had succeeded in producing a small amount of material in a rudimentary separator in the Riken complex—material which Riken's cyclotron indicated was not uranium-235. The separator project came to an end two months later when the building housing it was destroyed in a fire caused by the USAAF's Operation Meetinghouse raid on Tokyo. No attempt was made to build a uranium pile; heavy water was unavailable, but Takeuchi Masa, who was in charge of Nishina's separator, calculated that light water would suffice if the uranium could be enriched to 5–10% uranium-235.[11] Personally I wouldn't be surprised if the US managed to spend as much on its Manhattan project as Japan did in all of its war research

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 16 Mar 2015 03:03

Genro wrote:“ I would really like to see a bomb physicist do a calculation----“ 18 Dec 2003 04:02
Who wrote that ?

With out at least some comprehension of science this sort of rubbish gets printed and believed by many.

‘Gauges at the top and bottom of the column, intended to measure a difference in pressure - showing that separation was taking place - indicated no difference at all.’
The Making of the Atomic Bomb. Richard Rhodes.

The less said about Wilcox’s books the better they are considered a joke in physics.

Here is a thought, if Japan had had the industrial and financial muscle that America had at the time, the atomic bomb would probably have been made in half the time and at half the cost and with the need of brains from Europe.

Do you ever just, you know, answer a direct question, directly? You should try it sometime, it's quite refreshing.

As near as I can determine---and it's difficult with you and your evident passive aggression, because most of what you say comes out sideways---your repeated "novelist" comment is intended as a smear against Wilcox. Which, again, has absolutely zero---nothing whatosever---to do with the issue that was being discussed and about which I asked you: YOUR STATEMENT, which YOU CLAIM was directly from Nishina, that he had achieved 10% enrichment in the small quantities of uranium with which he was working at the Riken. Seeing as how you seem to identify quite strongly with Japan, my guess is that you are echoing a comment made ca. 1985 by a prominent Japanese citizen in response to Wilcox's book: "He's just a novelist". If this is what you think, here's a suggestion for you: Why don't you just say so in so many words, and then list for us the specific passages in Secret War that you believe "...are considered a joke in physics" and why? Along the way maybe you'll also tell us why Wilcox is wrong in other ways, ie, journalistically and historically. And I'll go a step further, not that I expect a straight answer from you: have you ever actually read Secret War? If I had to guess, my guess would be that you have not. Most of the mouthiest critics of Wilcox whom I have encountered have never read his book, a truly curious phenomenon if there ever was one. But, maybe you're the exception to this trend.

To answer your question directly, a courtesy that you do not return to me, here is my entire quote from 12 years ago:

"I would really like to see a bomb physicist do a calculation of the explosive force of a fission bomb with a slower compression speed, so we would know once and for all what kind of yield the Japanese weapon would actually have had---again, assuming they did not do any further refinement of their warhead design after 1943, an unlikely proposition, it seems to me. Unless the Nishina interview took place in 1943 and the warhead design was done later; the Japan Times article does not specify this."

As I have already stated repeatedly, for public consumption, on the internet---both in this thread and elsewhere---and under my own name, I was making that statement based on the text of two (2) articles I used as sources for my article. These were the BBC News website piece, "Atomic Plans Returned to Japan" and the Japan Times piece, "Japan's A-Bomb Goal Still A Long Way off in '45". Both of these, but particularly the BBC article, claimed that the information in the Kuroda Papers was sufficiently detailed to constitute a bomb design; the BBC piece outright called this a "blueprint" and stated that the result would have been "a weaker weapon". While I am---obviously---not a nuclear physicist, I do know that in a gun type weapon it is necessary to ram the two subcritical pieces of fissile material together at a sufficiently high speed to ensure a detonation and not a fizzle. The Japan Times piece said that Nishina had made a calculation error such that he thought the two uranium components would detonate if they came together in 1/20th to 1/30th of a second and not the 1/200th to 1/300th that is really necessary. Alright, you are claiming not only that this is incorrect from an engineering standpoint but also, apparently, that the Kuroda Papers don't say that at all, and that Nishina did not make the calculation error that the article said he did. I'm assuming you can see for yourself that I was relying on these articles for accuracy and that if they are not accurate in these details, then obviously and as a direct result, some of what I wrote in my piece (and elsewhere) is mistaken as well.

In short, if I am in fact mistaken in what I wrote because these two articles are themselves mistaken, hey, let's get it straight so that the historical record will be set straight. That's the only agenda I have here.

Now, let's try a final time to put some direct questions to you to see if you will give straight answers.

QUESTION ONE: Did Nishina, in fact, achieve 10% enrichment, or not? Yes, or no?

I repeat: You state upthread that it was Yoshio Nishina himself who stated, in the Tonizo Report(s), that he had achieved 10% enrichment in small quantities of uranium at his Riken thermal diffusion pilot plant. And yet, in the post immediately above this one, you quote Richard Rhodes (one of the very few American writers who has ever seriously investigated the WWII Japanese atomic bomb projects) as stating that Nishina's apparatus did not achieve ANY enrichment. At what point was Nishina saying (according to you) that he HAD achieved 10% enrichment, and at what point is Rhodes saying he HAD NOT? At the end of the Riken project in April 1945? When Nishina was kicked to the curb in 1944? When? And which of these two contradictory statements is correct, and how do you know that?

QUESTION TWO: Do you believe that Japan was in fact trying to build atomic bombs in WWII? Yes, or no?

QUESTION THREE: Since what I wrote on the subject was "rubbish", why don't you, the presumed expert, enlighten us all on the REAL bomb physics of a gun-type atomic fission bomb?

Just how fast do the two subcritical HEU pieces have to come together in order to detonate? Is there a specific threshold that will always result in a fizzle if the speed of the bullet into the target is below that threshold, or do other factors such as the purity of the HEU and the size and shape of the target affect the potential detonation?

Here is a thought, if Japan had had the industrial and financial muscle that America had at the time, the atomic bomb would probably have been made in half the time and at half the cost and with (sic) the need of brains from Europe.

QUESTION FOUR: I presume you meant to say, "...WITHOUT the need of brains from Europe"?

As though Japanese science developed completely independently of Europe. Oh, wait: it didn't? Oh, that's right. Nishina studied under Niels Bohr, and Arakatsu under Albert Einstein. Oops. Nishina also benefited greatly from his relationship with the American physicist Ernest Lawrence, who despite being edgy-muh-kated entirely in inferior US institutions somehow managed to, you know, invent the cyclotron. But he was the exception in terms of his formal studies. The fact is, nearly every major nuclear weapons physicist in the world of that era was educated in part or in whole in Germany. But you just couldn't help yourself, and had to get in another gratuitous anti-American dig. Jolly good for you, Genro. By the way, the US - Allied effort under Oppenheimer would almost certainly have been able to build its gun-type U-235 bomb, Little Boy, with little or no help from exiled continental European scientists. Where those people were of the most direct and comprehensive aid to the Americans was in the Fat Man plutonium implosion bomb. Like the US, Japan was also trying to build the much less sophisticated gun-type weapon, but nevertheless their science---such is your clear and petulant implication---was superior to the US. It just wasn't fair, I guess, that the Americans---drat the luck!!!---just happened to have all that industrial capacity and manufacturing power lying around, and of course none of that had anything to do with their success, you see. They just dumb-lucked their way into an atomic bomb, since we all know, don't we, Precious, that all Americans are idiots.

Some are, of course. But not in this case.

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Re: The Japanese nuclear weapons program

Post by Genro » 16 Mar 2015 10:54

‘Without’ you got it!
You seem to forget that the idea of the atomic bomb was born in Britain and America had to be cajoled into getting off it’s back side to take an interest. It needed Japan to get America to wake up. For a year only Britain alone stood up for democracy.

Having got an atomic bomb at the end of the war, America promptly cut Britain out of the project and so Britain developed it’s own bomb. After five years of war and severe deprivation, Britain managed not only a fission but also a hydrogen bomb.

This attitude of denigration of Japan’s and Germany‘s efforts on the atomic bomb project I found very common at Los Alamos compared with AWRE.
Goudsmit’s Alsos report on the German nuclear research was totally discredited with the release of the Farm Hall transcripts in 1993.
As the bard said, ‘render unto Caesar what is Caesar’s’

His own country having been devastated by the very thing he had been obliged to work on , Nishina was magnanimous enough to acknowledge it as’ a magnificent product of pure physics’.

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 16 Mar 2015 11:44

Yes, the Manhattan Project---in the sense that it was ultimately the combined efforts of the Western Powers (ie, the Allies minus the Soviets and the "minor" nations who were fighting the Axis)---could be said to have originated with the MAUD Committee and the "Tube Alloys" project. To be sure, the contributions made by British and Canadian scientists were significant and considerable. No, those contributions could not, at least to my mind, be characterized as "decisive", welcome and helpful though they certainly were. Yes, the British development of their own nuclear weapons and their attendant delivery systems in the immediate postwar years was an impressive achievement on its own merits.

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Re: The Japanese nuclear weapons program

Post by williamjpellas » 23 Apr 2015 03:12

As the bard said, ‘render unto Caesar what is Caesar’s’

Actually, Shakespeare wasn't the first to say "render unto Caesar that which is Caesar's". That was actually Jesus Christ, in Luke 20: 20-26.

https://www.biblegateway.com/passage/?search=Luke%2020

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