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| Fig. 1: This figure shows how large and powerful the Crossroads Baker explosion was, especially when looking closely to see the scale of the explosion against the size of the military ships at its roots. (Source: Wikimedia Commons) |
The Bikini Atoll is part of the Marshall Islands that was used by the United States during and after World War II to test bombs, including ones that were nuclear. Before the tests were conducted, the Bikinian people were asked to leave on the basis that the testing was for the good of mankind and to end all world wars. [1] The removal of the Bikinian people, carried about by around 42,000 soldiers, left ample room for a wide variety of targets to be brought into the lagoon, everything from cruisers and destroyers to submarines and full sized carriers. [1] With the targets in place, the stage was set for the first series of nuclear bombs to be tested in the summer of 1946. This was part of what's known as Operation Crossroads, which saw the underwater detonations of bombs Able and Baker, the latter of which is shown in Fig. 1 to the right. While there were plans for a third bomb, Charlie, to be tested after the first two bombs, the contamination from Baker was so severe, that Operation Crossroads was scrapped. It was not until 1954 that the tests restarted, beginning with the test of Castle Bravo.
At the turn of the decade and into the early 1950s, Cold War war tensions increased the pressure to discover and test larger and more power nuclear weapons. Despite the scrapping of the earlier Crossroads series of tests, many more series were conducted, including Operation Ivy, which demonstrated that a thermonuclear reaction, fueled by liquid deuteride, was possible. [2] While that was seen as a success, more test series followed as liquid deuteride required refrigeration, making it impossible to use in a missile. To address this issue, in 1945 the Castle series began in order to determine whether lithium deuteride, which could be placed into the nose of a missile, could be used for fuel instead. [2] The first in the series to be tested, a 15-megaton bomb called Bravo, was detonated on March 1st. 1,000 times stronger than the bomb that decimated Hiroshima, Castle Bravo caused immediate and lasting damage in the atoll and to the surrounding islands. [2] While those involved with making the bomb had considered that a 15-megaton yield was possible, the size of the detonation still came as a surprise as that was considered the maximum yield with the more probable yield predicted to be much lower. [3]
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| Fig. 2: This figure shows how far reaching the fallout from Bravo was and how long it took to get there. [5] (Source: Wikimedia Commons) |
The power displayed by the detonation of Bravo was staggering and as Fig. 2 shows, its fallout hit atolls as far away from the detonation site as Rongelap and Utirik. [4] A Japanese fishing boat, the Daigo Fukuryū Maru (The Lucky Dragon 5), became notable in the history of Castle Bravo as it had been fishing 85 miles to the east of Bikini when the explosion occurred. [2] Coral and ash rained down on the crew, and when they returned to Japan, the crew was hospitalized for acute radiation sickness. Their contamination sparked outrage in Japan who were upset not only over their countrymen being hurt from the nuclear fallout but also due to fear of the contaminated fish that the ship brought home. It is from the Japanese outrage over what occurred at Bikini Atoll that Americans began to find out what had occurred thousands of miles away. [5] Additionally, six months after the explosion, the radioman for The Lucky Dragon 5, Aikichi Kuboyama, died from radiation poisoning which marked the first recorded death attributed to Castle Bravo. [5]
© Andrew Chun. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] R. L. Guyer, "Radioactivity and Rights: Clashes at Bikini Atoll," Am. J. Public Health 91, 1371 (2001).
[2] D. M. Blades and J. M. Siracusa, A History of U.S. Nuclear Testing and Its Influence on Nuclear Thought, 1945-1963 (Rowman and Littlefield, 2014).
[3] T. Kunkle and B. Ristvet, "Castle Bravo: Fifty Years of Legend and Lore," U.S. Defense Threat Reduction Agency, DTRIAC SR-12-001, January 2013.
[4] A. Liang, "Castle Bravo," Physics 241, Stanford University, Winter 2017.
[5] C. Emery, "Fifty Years after Bikini Atoll," Front. Ecol. Environ. 2, 119 (2004).
