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Race for the Superbomb | Article

U.S. Tests

The "George" Test 

In the summer of 1950, while scientists at Los Alamos were feverishly working on calculations to see if the classical super, the initial design for the hydrogen bomb would work, the weapons laboratory was also preparing for a new series of nuclear tests in the Pacific. Among the devices they were going to detonate was one that would involve thermonuclear reactions (i.e. the fusion of deuterium) and tritium atoms. The test of the device came to be called "George". 

"George" was not a design for a hydrogen bomb. But at a time when Los Alamos was totally stymied about how to build such a weapon, "George" was an experiment that would allow scientists to observe a thermonuclear reaction, while showing politicians in Washington that they were making some headway. 

The design was similar to ideas for a hydrogen bomb that atomic spy Klaus Fuchs had patented with mathematician John von Neumann in 1946. It placed an atomic bomb inside a heavy shell, close to a capsule of hydrogen fuel. At the moment of detonation--in the fraction of a second before the whole assembly blew itself apart - the shell would confine the radiation from the atomic blast long enough to heat and compress the hydrogen fuel, setting off a fusion reaction. Because "George" used such a large atomic bomb and such a small amount of hydrogen fuel everyone was pretty sure it would work. One scientist compared the design to using a blast furnace to light a match. 

Ironically, while the preparations for "George" were underway, mathematician Stanislaw Ulam came up with a breakthrough for an actual hydrogen bomb design. He realized that rather than relying on heat, as the design for the classical super did, to initiate a thermonuclear reaction, the enormous flux of neutrons emitted during the explosion of an atomic bomb could be used to compress the deuterium and tritium causing a fusion reaction. He suggested putting the atomic bomb and hydrogen fuel in a shell which would reflect the neutrons. He also suggested surrounding the hydrogen fuel with material that would effectively magnify the energy of the neutrons. 

Since Teller had been working on "George," which used radiation to compress the hydrogen fuel, he realized that the radiation emitted by the atomic bomb would actually work far more effectively in imploding the deuterium tritium mixture. Together Teller and Ulam published their ideas in a report that was released on March 9, 1951. It was their design that led to the creation of the U.S. hydrogen bomb. 

The Ulam-Teller breakthrough put the "George" test in a completely new light; it now promised to provide information on radiation implosion. The test took place on May 9 on Eniwetok Atoll in the Marshall Islands of the Pacific. Teller was there to witness it. "We felt the heat of the blast on our faces," he recalled, "but we still did not know if the experiment had been a success. We did not know whether the heavy hydrogen had been ignited." 

That afternoon as they waited to hear whether or not the experiment had worked, Teller bet another scientist five dollars that the experiment had been a failure. He lost the bet. Analysis of the explosion showed that the deuterium and tritium, which weighed less than an ounce had yielded the equivalent of about 25 kilotons of TNT, more than twice the force of the Hiroshima bomb. 


"Mike" Test 

On November 1, 1952 the United States detonated a hydrogen device in the Pacific that vaporized an entire island, leaving behind a crater more than a mile wide. The test, code-named "Mike" was the first successful implementation of the concept for a superbomb that physicist Edward Teller and mathematician Stanislaw Ulam had outlined in a report a year and a half earlier. A team of scientists assigned the task of turning the Ulam-Teller concept into an experimental device, met for the first time in October 1951. They achieved the designated goal, one that required a tremendous engineering effort, in little more than a year. 

The design process was complicated by the sort of hydrogen fuel the team decided to use. One option would have been lithium deuteride, which has the advantage of being a solid at room temperature. But the scientists had limited information on how well it would work. They chose instead to use liquid deuterium, which needed to be kept below it's boiling point of -417.37 fahrenheit. That meant the device would require a very complex insulation and cooling system. 

"Mike" was also incredibly large. In 1952, the smallest atomic bomb with enough explosive force to set off a fusion reaction, was almost four feet in diameter. The actual casing for the "Mike" gadget would end up being 20 feet long. According to one of the scientists who worked on the project, a full-scale drawing of the device became essential for everyone on the team to communicate effectively with each other. The drawing was so big, that a balcony had to be built from which to view it. 

As the date for the test approached, a number of prominent scientists not involved with the project pushed to have it postponed. The reasons they gave were political. "Mike" was scheduled to be detonated just three days before a general election. Many scientists felt that it was wrong to burden a new president with the responsibility for a nuclear test that he had not authorized. They also argued that by testing "Mike" the U.S. would effectively eliminate any opportunity it had for reaching an agreement with the Soviet Union for a moratorium on thermonuclear weapons. But after listening to the arguments, President Truman decided to proceed as planned. 

The test was to take place on Eniwetok Atoll, which is in the Marshall Islands about 3,000 miles west of Hawaii. It was an enormous operation. Staging began in March and by October more than 11,000 civilians and military personnel were in the vicinity of Eniwetok working on the project. A six-story cab was built on the island of Elugelab to house "Mike." And a two-mile long tunnel that extended from the device to another island was filled with helium balloons that would provide data on the progress of the fusion reaction. 

"Mike" was detonated remotely from the control ship Estes, which was stationed 30 miles away from ground zero. Even those who had witnessed atomic tests were stunned by the blast. Within 90 seconds the fire ball had reached 57,000 feet. The cloud, when it had reached its furthest extent, was about 100 miles wide. The explosion wiped Elugelab off the face of the planet, and destroyed life on the surrounding islands. In their report, the survey team that went to Engebi three miles from ground zero wrote, "The body of a bird was seen, but no living animals and only the stumps of vegetation. Among the specimens collected were fish which seemed to have been burned. On each of these fish, the skin was missing from one side, as if, the field notes said at the time, the animal 'had been dropped in[to] a hot pan.' " 

Physicist Herbert York summed up the implications of the first test of a thermonuclear device: "the world suddenly shifted from the path it had been on to a more dangerous one. Fission bombs, destructive as they might have been, were thought of [as] being limited in power. Now, it seemed we had learned how to brush even these limits aside and to build bombs whose power was boundless." 

The "Bravo" Test 

On March 1, 1954 the United States tested an H-bomb design on Bikini Atoll that unexpectedly turned out to be the largest U.S. nuclear test ever exploded. By missing an important fusion reaction, the Los Alamos scientists had grossly underestimated the size of the explosion. They thought it would yield the equivalent of 5 million tons of TNT, but, in fact, "Bravo" yielded 15 megatons -- making it more than a thousand times bigger than the bomb dropped on Hiroshima. 

The blast gouged a crater about a mile wide in the reef. Within seconds the fireball was nearly three miles in diameter. The illumination from the blast was visible for almost one minute on Rongerik, an island 135 miles east of the burst. It trapped personnel in experiment bunkers and engulfed the 7,500 foot diagnostic pipe array. Physicist Marshall Rosenbluth was on a ship about 30 miles away. He remembers that the fireball, "just kept rising and rising, and spreading... It looked to me like what you might imagine a diseased brain, or a brain of some mad man would look like on the surface... And the air started getting filled with this gray stuff, which I guess was somewhat radioactive coral." 

An hour-and-a-half later a similar gritty, snow-like substance began raining down on a Japanese fishing vessel called the Lucky Dragon that was about 80 miles east of Bikini. The 23 fishermen aboard had no idea the ash was fallout from a hydrogen bomb test. When they returned to port two weeks later they were all suffering severe radiation sickness. The radio operator later died. One Tokyo newspaper headline demanded that the U.S. authorities "Tell us the truth about the ashes of death." 

Marshall Islanders were also exposed to the fallout. One islander on Rongelap about 100 miles east of Bikini remembers hearing, "a loud explosion and within minutes the ground began to shake. A few hours later the radioactive fallout began to drop on the people, into the drinking water, and on the food. The children played in the colorful ash-like powder. They did not know what it was." 

On Rongerik (about 135 miles east of Bikini), 28 U.S. service personnel operating a weather station grew alarmed when the meter reading on their fallout monitoring equipment went off the scale. They radioed the communications center and took cover inside a tightly closed building. The service personnel were evacuated within 34 hours. The Marshall Islanders, who had been closer to the blast, weren't rescued for another day, by which time many of them had severe burns and were beginning to lose their hair. 

In a press conference, shortly after the blast, Atomic Energy Commissioner Lewis Strauss claimed that, "meteorologists had predicted a wind condition which should have carried the fallout to the north of a group of small atolls lying to the east of Bikini... The wind failed to follow the predictions but shifted south of that line and the little islands of Rongelap, Rongerik and Utirik were in the edge of the path of the fallout." But in fact a weather report just seven hours before the shot predicted "less favorable winds at 10,000 - 25,000 foot levels" with winds at 20,000 feet "headed for Rongelap to the east." 

In 1955, the United States paid two million dollars as restitution for damage to the Lucky Dragon, its 23 crew members and its cargo. And in 1988, the Marshall Islands Nuclear Claims Tribunal was established to grant compensation to Marshall Islanders for personal injury deemed to have been caused by nuclear testing. As of December 31, 1997, $63,127,000 had been awarded to or on behalf of 1,549 people. With more personal injury claims and several class action suits for property damage still pending, the Tribunal claims that the original terms of the settlement with the Marshall Islanders are grossly inadequate.

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