Japanese Nuclear Weapons Research during WW II

http://ajw.asahi.com/article/behind_news/social_affairs/AJ201506290078

Wartime documents shed light on Japan’s secret A-bomb program

June 29, 2015

THE ASAHI SHIMBUN


Long-forgotten documents on Japan's attempt to build an atomic bomb during World War II have been discovered at Kyoto University, which experts say further confirms the secret program's existence and could reveal the level of the research.

The newly found items, dating between October and November 1944, were stored at Kyoto University’s research center. Research into uranium-enrichment equipment, a key to the production of atomic weapons, was scribbled in three of the notebooks.

Japan surrendered in August 1945 before the secret project could reach fruition.

“The new data could show us the level of research they were involved in,” said Hitoshi Yoshioka, a professor who studies the history of scientific technology at Kyushu University.

It has long been known that two programs were under way in Japan to produce a nuclear weapon during the war.

One, commissioned by the Imperial Japanese Navy and code-named “F Research,” involved Bunsaku Arakatsu, a professor of physics at Kyoto Imperial University, the predecessor of Kyoto University, and other leading researchers at the institution.

The other, carried out by the Imperial Japanese Army and known as the “Nigo Research” project, was spearheaded by Yoshio Nishina, a physicist at the Riken institute in Tokyo.

Yoshioka, well versed in the development of nuclear-related technology, noted that there are few known documents on the research that took place at Kyoto Imperial University compared with that conducted at Riken.

The notebooks in question belonged to Sakae Shimizu, a researcher who worked for Arakatsu.

Akira Masaike, 80, professor emeritus on nucleus at the university, discovered the notebooks along with other documentation at the university’s former Radioisotope Research Center, to which Shimizu was once assigned.

The team at Kyoto Imperial University was trying to develop equipment to separate and enrich Uranium-235, which is found in uranium ore and is key to generating the chain reaction in nuclear fission.

The notebooks, titled “Ultracentrifugal separation,” came with tables showing equipment revolutions and numbers, and photos of relevant research papers from abroad.

Also among the find was a paper listing the material used to build uranium enrichment equipment and figures detailing the diameters and lengths of components and parts. Only a limited number of documents detailing Japan’s nuclear weapons program remain in the nation. U.S. authorities confiscated most of the research data after the war, according to Masaike.

“The significance of the recent discovery lies in the fact that the documents confirm the existence of research into the development of centrifuge separators at Kyoto Imperial University,” he said.

THE ASAHI SHIMBUN​

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EDIT: Renamed to reflect that the IJN actually had two atomic weapons projects during WWII (one subsequent to the other).

Interesting!!
Thanks for sharing Grey Havoc

Regards
Pioneer

Not meaning to start a flaming thread-war here but just so you have a few quotes to hand, below are some short extracts from Richard Rhodes' Pulitzer-winning The Making of the Atomic Bomb, (1986), from pages 458, 580 and 582, on the scope and limitations of Japanese WW2 atomic bomb research:
https://books.google.co.uk/books?id=aSgFMMNQ6G4C&source=gbs_navlinks_s

Also this, from Rhodes p. 375, on Japanese physicist, Tokutaro Hagiwara, being the first to see the potential to use fission to ignite a fusion weapon.
More on Hagiwara: http://www.atomicarchive.com/History/hbomb/page_01.shtml

Rhodes' claim seems to have been generally accepted but for a sceptical view, see Shuji Fukui's paper here - English abstract in PDF attached:
https://watanaby.files.wordpress.com/2013/01/fukui-5.pdf

EDIT: Found this handy summary just now:

"In The Making of the Atomic Bomb (1986), Richard Rhodes reported that Tokutaro Hagiwara at the University of Kyoto was the first person to conceive of igniting a thermonuclear reaction based on a single statement translated from a hand-written summary of a speech given by Hagiwara on 23 May 1941. The statement read: "If by any chance U-235 could be manufactured in a large quantity and of proper concentration, U-235 has a great possibility of becoming useful as the initiating matter for a quantity of hydrogen."
Hagiwara himself never claimed any credit for conceiving this, and in June 1999 a copy of the original speech was obtained from Hagiwara's daughter. Upon examination it was discovered that a kanji character substitution had occurred in hand-copying the original speech text, changing "super" to "initiating". The actual text stated: "If in some way it becomes possible to manufacture a fairly large amount of U-235 and mix it with a suitably concentrated hydrogen on an appropriate scale, the U-235 is expected to have a high probability of causing a super explosion." This refers to the incorrect idea that an atomic explosion requires a moderator, which was held by many early investigators of atomic weapons.

Shuji Fukui, Tetsuji Imanaka, James C. Warf, The Bulletin of the Atomic Scientists, Vol. 56, No. 4, July/August 2000, p. 5, 65."

Quoted from: http://nuclearweaponarchive.org/Nwfaq/Nfaq8.html

Glad you found it of interest.

Here's a related thread over at the Bar: http://www.secretprojects.co.uk/forum/index.php/topic,27175.0.html

You're a l

Grey Havoc said:

http://ajw.asahi.com/article/behind_news/social_affairs/AJ201506290078

Wartime documents shed light on Japan’s secret A-bomb program

June 29, 2015

THE ASAHI SHIMBUN


Long-forgotten documents on Japan's attempt to build an atomic bomb during World War II have been discovered at Kyoto University, which experts say further confirms the secret program's existence and could reveal the level of the research.

The newly found items, dating between October and November 1944, were stored at Kyoto University’s research center. Research into uranium-enrichment equipment, a key to the production of atomic weapons, was scribbled in three of the notebooks.

Japan surrendered in August 1945 before the secret project could reach fruition.

“The new data could show us the level of research they were involved in,” said Hitoshi Yoshioka, a professor who studies the history of scientific technology at Kyushu University.

It has long been known that two programs were under way in Japan to produce a nuclear weapon during the war.

One, commissioned by the Imperial Japanese Navy and code-named “F Research,” involved Bunsaku Arakatsu, a professor of physics at Kyoto Imperial University, the predecessor of Kyoto University, and other leading researchers at the institution.

The other, carried out by the Imperial Japanese Army and known as the “Nigo Research” project, was spearheaded by Yoshio Nishina, a physicist at the Riken institute in Tokyo.

Yoshioka, well versed in the development of nuclear-related technology, noted that there are few known documents on the research that took place at Kyoto Imperial University compared with that conducted at Riken.

The notebooks in question belonged to Sakae Shimizu, a researcher who worked for Arakatsu.

Akira Masaike, 80, professor emeritus on nucleus at the university, discovered the notebooks along with other documentation at the university’s former Radioisotope Research Center, to which Shimizu was once assigned.

The team at Kyoto Imperial University was trying to develop equipment to separate and enrich Uranium-235, which is found in uranium ore and is key to generating the chain reaction in nuclear fission.

The notebooks, titled “Ultracentrifugal separation,” came with tables showing equipment revolutions and numbers, and photos of relevant research papers from abroad.

Also among the find was a paper listing the material used to build uranium enrichment equipment and figures detailing the diameters and lengths of components and parts. Only a limited number of documents detailing Japan’s nuclear weapons program remain in the nation. U.S. authorities confiscated most of the research data after the war, according to Masaike.

“The significance of the recent discovery lies in the fact that the documents confirm the existence of research into the development of centrifuge separators at Kyoto Imperial University,” he said.

THE ASAHI SHIMBUN​

Click to expand...

EDIT: Renamed to reflect that the IJN actually had two atomic weapons projects during WWII (one subsequent to the other).

Click to expand...

You're a little bit behind the times Grey Havoc!
See the History Channel documentary video: "Japan's Atomic Bomb"

Xylstra,
honestly, to tell someone, that he is behind time, when answering to a more than 4 years old post is ... what ?
Offensive, mocking, or just a joke ?
Careful, please ! Rhetorical devices like irony often get lost in written form. Please, regard this as a warning.

History Channel? Seriously? Isn't American 'infotainment' cable television notoriously inaccurate anyway?

The Japanese atomic project was fully developed. See this book: