Radioactive Fallout and the Birth of the “Superbomb”

 

Event Baker test explosion, Bikini Atoll, July 1946.

 

[Part 2 of 2]

While Linus Pauling’s immediate concern with the new hydrogen bomb was avoidance of a global nuclear conflict, he was also very uneasy about the threat of nuclear fallout.

As is now commonly understood, dangerous byproducts result from the fission fraction of radioactive materials following the detonation of atomic weapons. Much of the radioactive material released during such an explosion, widely referred to as fallout, eventually falls to the Earth’s surface. The exact distribution of the fallout depends largely on how closely the bomb is detonated to the surface of the Earth, as well as the direction and intensity of winds near the Earth’s surface.

Humans that come into contact with fallout can develop radiation poisoning – a condition that, depending on the level of exposure, is hazardous and potentially fatal. The outcome of consistent exposure to large amounts of radiation became relatively easy to predict, but little was known during the early 1950s about long-term exposure to smaller amounts.

The radiation released from atomic bomb tests was a relatively small addition to the total amount of other man-made and naturally occurring sources in the atmosphere. However, Pauling feared that even a small increase in radiation could significantly increase the risk of harmful genetic mutations to vulnerable populations. As a result of the accumulated nuclear fallout from ongoing atomic testing, Pauling predicted a higher frequency of medical complications and birth defects world-wide over the next several generations. As with the case of long-term exposure to small amounts of radiation, the long-term effects of nuclear fallout were very difficult to control for, lending Pauling’s grave warnings serious cause for consideration.

The uncertainty regarding fallout and radioactivity from nuclear explosions likewise allowed for a wide spectrum of alternative perspectives to emerge. Though Pauling’s warnings about nuclear fallout received ample attention, he was challenged by several conflicting counter-claims, especially those of the Atomic Energy Commission and of nuclear physicist Dr. Edward Teller.

 

Portrait of Edward Teller by Dmitri Vail. June 1965.

 

The debate that came to define Pauling and Teller’s interaction, and the contrasting viewpoints that they represented, would last for decades. Teller argued that the actual level of long-term radiation resulting from nuclear fallout was negligible when other forms of radiation were taken into consideration. Using essentially the same data as Pauling, he demonstrated that the average risk to any one person from fallout-related radioactivity was minimal, at least for those positioned outside of a certain blast radius. Furthermore, he argued that most people were subjected to more radiation annually by cosmic rays (among other sources), than they were from the fallout of a typical well-planned nuclear detonation.

Pauling and Teller were given several forums for debate on television and other outlets in the mainstream media. Though they were not on friendly terms, and often characterized in the media as completely at odds, historians and more moderate voices in the general discussion believed that Pauling and Teller had more in common than was popularly perceived. In a 2001 lecture, author and Pauling biographer Tom Hager had this to say about the general debate:

It was inconclusive to a certain extent because each side used the same data two different ways. And depending on how you look at the data, it can either look like fallout is going to cause 200,000 miscarriages and deaths of infants over the next few generations, or atomic fallout poses a danger equivalent to wearing a watch with a radium dial. Now, those were the kind of terms that were used in the debate and they were both correct. Pauling looked at the worst case scenario over many generations worldwide and the Atomic Energy Commission looked at the increased risk for an individual during their lifetime. In both cases, they were coming to correct or essentially correct conclusions, but the debate was framed in a way on Pauling’s side so that it aroused world opinion against atomic testing.

Pauling remained involved in the discussion of nuclear fallout and the politics of atomic weapons in the following years, but gradually receded from the scene as his public profile began to cause trouble for him at Caltech and with investigatory bodies. He was pulled back into the fray, however, when, in 1954, an unexpected reaction resulted from the detonation of a secret new type of atomic weapon.

This mysterious bomb, detonated on the Bikini Atoll in the Pacific Ocean, surprised even the scientists who were testing it. Several military personnel overseeing the test were subjected to unexpected levels of radiation, as was the crew of a Japanese fishing boat that had wandered into the area unaware of the danger. The men on the fishing boat, sick from radiation poisoning and carrying a hull of contaminated fish, were analyzed by Japanese scientists. Judging by the type of radiation damage discovered in the men, it was clear that something unusual was involved with the test to which they had been subjected.

This “superbomb” as it would commonly be known afterward, involved the coating of a hydrogen bomb with ordinary uranium metal or uranium-238, a by-product of the uranium enrichment process. Typically unfit for use in nuclear weapons, the uranium was destabilized during a three-stage reaction using a fission-fusion-fission detonation process. The resulting explosion penetrated a hole into the upper regions of the atmosphere, where radioactive materials were deposited and capable of traveling much greater distances on the high elevation winds.

This new development quickly re-energized Pauling’s public outspokenness. The relative silence that he had attempted to maintain for several of the preceding years was shattered by his concern over the powerful new bomb. In due course, he gave his first bomb-related speech in over two years and became engaged with the ongoing conversation once again.

The fallout debate, filled with victories and defeats for Pauling and the anti-testing community, would remain frustratingly unresolved throughout much of the following century. Over the course of many difficulties however, Pauling never lost sight of his hope for world peace. Later in life, he recalled his thoughts following development of the original atomic bomb in 1945:

I came to think, as did Albert Einstein, that the existence of nuclear weapons had finally made it imperative to abandon war once and for all. As seemed only logical to me, these weapons force us to accept the idea of coexistence and cooperation. Now that the facts about nuclear weapons are relatively well-known to the general public, we must realize that the future of the human race depends on our willingness and ability to cooperate and work together to solve global problems without belligerence.