Japanese atomic program
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During the 1930s, the scientific community in the world started to understand the power of nuclear energy, and Imperial Japan, like many other governments, was made aware of the possibility of developing a weapon which utilized nuclear fission as the source of its energy. The central figure of the Japanese atomic program is Dr. Yoshio Nishina, who also was a friend of Niels Bohr, and a close associate of Albert Einstein. Dr. Nishina was a highly skilled world class scientist with excellent leadership qualities. He also co-authored the Klein-Nishina Formula, and the Nishina crater on the moon is named after him.
Dr. Nishina established his own Laboratory at the Riken (the Institute for Physical and Chemical Research) in 1931 to study high-energy physics. He built his first 26 inch cyclotron in 1936, and another 60 inch 220 ton cyclotron in 1937. In 1938 Japan also purchased a cyclotron from the University of California, Berkeley.
Dr. Nishina knew and understood the military potential of nuclear weapons, and was worried that the Americans were working on a nuclear weapon, which could be—and eventually was—used against Japan. About the same time, in 1939, President Franklin D. Roosevelt started the first investigations into fission weapons in the United States, which eventually evolved into the massive Manhattan Project (the very laboratory from which Japan purchased its own cyclotron would become one of the major sites for weapons research). Dr. Nishina tried to match the U.S. research, and promoted the development of a nuclear weapon. In October 1940, Lt. General Takeo Yasuda of the Japanese army finally decided that such a weapon was feasible and practical, and the Japanese atomic program started in July 1941 under the guidance of Dr. Nishina.
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[edit] Atomic program of the Imperial Japanese Navy
A separate atomic program of the Imperial Japanese Navy was also in progress in 1942 [1]. This project, called F-Go, was headed by Prof. Bunsaku Arakatsu, a lecturer at the Kyoto University, who studied under Albert Einstein [2]. Arakatsu built his own cyclotron. His team included Hideki Yukawa, the first Japanese physicist to receive a Nobel Prize in 1949.
The program of the Navy initially aimed only to harness nuclear energy as an energy source to reduce the dependence on oil and to relieve the permanent shortage thereof, as it was thought that a weapon would not be able to be developed for wartime use (in this respect, it was very similar to the German nuclear energy project going on at the same time). However, as the tide of the war turned against Japan, the goal of making a nuclear weapon became a priority. The Japanese Navy launched a search for uranium throughout the dwindling empire. The Japanese military took what Nishina had learned and expanded the program, for instance, building five improved gaseous diffusion separators based on the smaller, single unit developed in Nishina’s effort. What happened to the separators, described by Col. Tatsusaburo Suzuki, who coordinated the effort for the army, is not known. But the Navy lacked time and material, and despite paying huge amounts for uranium on the Chinese black market and arranging for Nazi uranium to be shipped by submarine, it is generally assumed that they failed to produce a nuclear weapon. Exactly how far the Navy project got is a matter of debate. There have been some who contend that a prototype was developed, perhaps using Nazi supplied uranium or plutonium, and was detonated on a small island off the coast of what is today North Korea, only weeks prior to the bombing of Hiroshima. This conclusion has been disregarded by mainstream scholars (see below).
[edit] Development
The Japanese programs' source of uranium ore was Korea,[citation needed] which had been under Japanese control since 1910. Dr. Nishina investigated a number of methods for enrichment of uranium, and decided that the gaseous diffusion method would be most worth pursuing. However there is no evidence that production plants of the size used by the Manhattan Project were ever constructed, and the Manhattan Project plants, for all of their vastness, were only able to produce enough material for three bombs by the war's end.
Japan disclosed its program to its ally Nazi Germany, and requested assistance.[citation needed] It is not known how much material Japan received from Germany, but at least one shipment that was sent to Japan by a German submarine was intercepted [3].
This submarine, Unterseeboot 234 (U-234) was sent to Japan in 1945 to deliver 560 kg of unprocessed uranium oxide for the Japanese program, as well as a disassembled Me-262 jet fighter and parts for some German-designed missiles (which would have been of little use for a primitive nuclear weapon) [4]. Two Japanese military officials and a number of German experts were also on board. The nuclear cargo was labeled "U-235," perhaps as a mislabeling of the submarine name, or perhaps in reference to the fissile isotope of uranium, uranium-235. It is extremely unlikely, though, that it was truly 560 kg of uranium-235—this would have been some eight times more of the rare element than was produced by the entire U.S. effort, and enough for Nazi Germany to have built many atomic bombs of their own with great ease.[citation needed] It is more likely that the uranium was un- or partially-enriched uranium oxide (which naturally has over 99% uranium 238). The submarine was ordered to surrender on May 10, 1945, two days after the overall German surrender, by Admiral Dönitz. To avoid capture, the two Japanese officials, Lieutenant Commander Hideo Tomonaga and Lieutenant Commander Genzo Shoji, committed suicide and were buried at sea the next day. The submarine was boarded by US forces on May 14 and the cargo fell into U.S. hands [5].
Some reports[citation needed] claim that the 560 kg of uranium oxide was enough to build two atomic bombs, but this would mean that it was substantially enriched (and would have also meant that Germany could have developed its own bomb with it, which it did not). That amount of uranium, if enriched to around the 90% needed for an atomic bomb, would provide around 4 kg of bomb-grade material, far less than needed for an atomic bomb (the "Little Boy" uranium weapon dropped on Hiroshima used over 60 kg of uranium-235).
American bombing raids disrupted the development of the genshi bakudan, and both raw material and equipment was destroyed at the Institute for Physical and Chemical Research (Riken). To avoid further bombing, the Riken staff began to remove the remaining equipment out of Tokyo and the project was relocated to Konan (now called Hungnam, in North Korea) early in 1945, although there is no substantive evidence to support this claim. This region was closer to the source of ore, in less danger of attack than mainland Japan, and also a major industrial area in Asia. However, the move supposedly delayed the development by a critical three months. However dispite several set backs Japan was able to test a nuclear device 6 days after the first atomic bomb was dropped on Hiroshima. The test was conducted off the east coast of present day north korea. The test was successful and the scientist working on the project where ready to start production faze of the project but was scrapped by the anouncement of the surrender of japan by the emporer. After the war Konan, today known as Hungnam, was captured by the Russian army in late August 1945, and is currently within North Korea.
[edit] Aftermath
After the war, the U.S. occupation forces found a total of four cyclotrons, which they judged to be part of the weapons programs. (Some have mistakenly claimed there were five cyclotrons, but one was actually a mass spectrometer and referred to by some Japanese scientists at the time as "the baby cyclotron".) Cyclotrons can be used for electromagnetic uranium enrichment as mass spectrometers, but by themselves would not be useful as production facilities. In the United States, large cyclotrons at the Berkeley Radiation Laboratory were used to develop even more massive Calutron machines at the Oak Ridge facility, which were used for the bulk of the electromagnetic enrichment, but the Japanese cyclotrons would have been much smaller than even the prototype American machines. The Japanese cyclotrons were then dumped into Tokyo harbor by the U.S. Army, and many American scientists protested this act after the fact, insisting that the cyclotrons by themselves couldn't be used to make atomic weapons.
In many ways, the Japanese program is more similar to the abortive German atomic program than it was to the massive Allied bomb program. It is worth noting that by comparison, the Manhattan Project was one of the largest expenditures for the American side in World War II ($1.8 billion in 1945 dollars, with radar R&D costing some $3 billion), involved over 30 different research and production sites, and employed 150,000 employees, including numerous Nobel Laureates. Even with this investment, the USA was only able to produce three atomic devices by August 1945.
[edit] Current nuclear activities in Japan
Since the bombing of Hiroshima and Nagasaki, Japan is a staunch opponent of nuclear arms on all government levels. However, Japan does make extensive use of nuclear energy in nuclear reactors, generating a significant percentage of the electricity in Japan. Japan has the third largest nuclear energy production after the U.S. and France, and plans to produce over 40% of its electricity using nuclear power by 2010. Significant amounts of Plutonium are created as a by-product of the energy production, and Japan had 4.7 tons of plutonium in December 1995. Japan also possesses an indigenous uranium enrichment plant [6] - the same plant, or a secretly constructed plant using similar technology, could be used to make highly enriched uranium suitable for weapons. Japan has also developed the M-5 three-stage solid fuel rocket, similar in design to the U.S. LG-118A Peacekeeper ICBM. While there are currently no known plans in Japan to produce nuclear weapons, it has been argued Japan has the technology, raw materials, and the capital to produce nuclear weapons within one year if necessary, and some analysts consider it a de facto nuclear state for this reason. [7]
Some argue that there is little military advantage for Japan to develop nuclear weapons as China, its main potential adversary, has sufficient landmass to easily deter an attack. A few thermonuclear weapons would largely destroy Japan, but China could absorb a similar attack. Japan is safer under the U.S. nuclear umbrella. [8] Some analysts, however, fear that Japan may abandon its anti-nuclear arms stance in the face of North Korea's development of nuclear weapons as part of a wider nuclear arms race in eastern Asia, especially after that nation's nuclear test on October 9, 2006.
[edit] Disputed reports about the nuclear program in Konan in 1945
Very little is known about the size of the alleged atomic program in Konan though it is conventionally thought to have been small in comparison with the successful U.S. effort. In 1946, a journalist named David Snell working for the Atlanta Constitution wrote a sensationalist story which indicated that Japan had in fact successfully developed and tested a nuclear weapon in Konan. Snell was a former reporter, soon to become Life Magazine correspondent assigned to the 24th Criminal Investigation Detachment in Korea. He interviewed a Japanese officer who said he had been in charge of counter intelligence at the Konan project before the fall of Japan.
According to the officer, who used a pseudonym in the article because he was afraid of retaliation by occupation forces, the program was able to assemble a complete nuclear weapon in a cave in Konan and detonate it on August 12, 1945 on an unmanned ship nearby. Reportedly, the weapon produced a mushroom shaped cloud with a diameter of about 100 m (the first American bomb, "Trinity", had a mushroom cloud some three times the size of that), and also destroyed several ships in the test area. To the observers 20 mi (32 km) away, the bomb was brighter than the rising sun. The officer then claimed that the Russian Army, which captured Konan in November 1945 after some of the last fighting in the war, dismantled the Japanese project and shipped it and some of its scientists taken prisoner back to the Soviet Union.
Most mainstream historians dispute that the Japanese program got close to developing an atomic bomb but US intelligence took the possibility very seriously after Snell's article was published and continued to question repatriated Japanese from the Konan area about the project.
A 1985 book by Robert Wilcox reprinted the Snell interview as a basis for investigating the Japanese WWII nuclear efforts. In addition to detailing the known Japanese army and navy efforts, the book cites numerous intelligence reports and interviews which indicated the Japanese might have had an atomic program at Konan. It also gave evidence that the Japanese navy, taking up the atomic project after Nishina’s Riken had been destroyed, increased the Japanese efforts to make a weapon. The book, prefaced by Derek deSolla Price, Avalon professor of the history of science at Yale University, who endorsed it, was both panned and praised. Price wrote, “No longer can we maintain that a Japanese bomb just couldn’t have happened. Obviously it ‘nearly’ did. The only questions are how near and what does it do to our judgment on the one case we have of atomic warfare.” James L. Stokesbury, author of A Short History of World War II, wrote: “I had no idea the Japanese were working as seriously on an atomic bomb...this has to modify our perception of one of the crucial issues of the war.”
A review by a Department of Energy employee in the journal Military Affairs degraded it:
- Journalist Wilcox' book describes the Japanese wartime atomic energy projects. This is a laudable, in that it illuminates a little-known episode; nevertheless, the work is marred by Wilcox' seeming eagerness to show that Japan created an atomic bomb. Tales of Japanese atomic explosions, one a fictional attack on Los Angeles, the other an unsubstantiated account of a post-Hiroshima test, begin the book. (Wilcox accepts the test story because the author [Snell], "was a distinguished journalist"). The tales, combined with Wilcox' failure to discuss the difficulty of translating scientific theory into a workable bomb, obscure the actual story of the Japanese effort: uncoordinated laboratory-scale projects which took paths least likely to produce a bomb.
In the historical journal Isis, two historians of science said only of Wilcox's work that his thesis stood "on the flimsiest and most unconvincing of grounds," and surmised that the hidden agenda of such conspiracy theories was "to furnish a new exculpation for America's dropping of atomic bombs on Hiroshima and Nagasaki."
An article published in the journal Intelligence and National Security in 1998, based on a review of many of the same documents used by Wilcox, and more, came to a similar conclusion. The article cites several US military intelligence documents and Japanese corporate records of the Nitchitsu firm that ran most of the industry in Hungnam and found no substantive evidence of any nuclear research program existing there during the war.
[edit] See also
- Nuclear weapon
- History of nuclear weapons
- List of countries with nuclear weapons
- List of nuclear weapons
- Nuclear testing
[edit] References
- Richard Rhodes, The Making of the Atomic Bomb (New York, Simon and Schuster, 1986).
- Walter E. Grunden, Secret Weapons & World War II: Japan in the Shadow of Big Science (Lawrence: University Press of Kansas, 2005).
- Walter E. Grunden, "Hungnam and the Japanese Atomic Bomb: Historiography of a Postwar Myth," Intelligence and National Security [Great Britain] 1998 13(2): 32-60.
[edit] Disputed references
- Robert K. Wilcox, Japan's Secret War: Japan's Race Against Time to Build Its Own Atomic Bomb (New York: Morrow, 1985; reprinted with new information by Marlowe, New York, 1995).
- David Snell, "Japan Developed Atom Bomb; Russia Grabbed Scientists," Atlanta Constitution (2 Oct 1946), available online at a conspiracy-theory website, [9].
[edit] Criticism cited
- Roger M. Anders, Review of Japan's Secret War, in Military Affairs 50:1 (Jan 1986): 56-57, quote from 57.
- R.W. Home and Morris F. Low, "Postwar Scientific Intelligence Missions to Japan," Isis 84:3 (Sep 1993): 527-537, quote from 528fn3.
- "Newsman Says Japanese Had Atom Bomb and Russians Now Hold the Inventors," New York Times (3 Oct 1946), 22.
[edit] External links
- FAS: Nuclear Weapons Program: Japan - Federation of American Scientists
- Japan's A-Bomb - site claiming that Japan detonated an atomic bomb
- Japan's atomic bomb History Channel International documentary
