In 1953, President Eisenhower delivered a speech called “Atoms for Peace” to the United Nations General Assembly. He described the emer- gence of the atomic age and the weapons of mass destruction that were piling up in the storehouses of the American and Soviet nations. Although neither side was aiming for global destruction, Eisenhower wanted to “move out of the dark cham- bers of horrors into the light, to find a way by which the minds of men, the hopes of men, the souls of men everywhere, can move towards peace and hap- piness and well-being.”1 One way Eisenhower hoped this could happen was by transforming the atom from a weapon of war into a useful tool for civilization. Many people believed that there were unprec- edented opportunities for peaceful nuclear appli- cations. These included hopeful visions of atomic- powered cities, cars, airplanes, and rockets. Nuclear power might also serve as an efficient way to generate electricity in space to support life and machines. Eisenhower wanted to provide scientists and engineers with “adequate amounts of fission- able material with which to test and develop their ideas.”2 But, in attempting to devise ways to use atomic power for peaceful purposes, scientists realized how little they knew about the nature and effects of radiation. As a result, the United States began constructing nuclear test reactors to enable scientists to conduct research by produc- ing neutrons. American scientists and engineers carried out the “atoms for peace” initiative at the nearly 200 research and test reactors built in the 1950s and 1960s. These types of reactors are very different from power reactors, which are built to produce power by converting radioactive heat into electric- ity. In contrast, research and test reactors are used for scientific and technical investigations. Research reactors help engineers design experiments and build better reactors, while test reactors generate powerful radiation fields that enable scientists to study how materials respond to radioactive envi- ronments. Though commercial and academic institutions built some research and test reactors, the government supported the large majority of them. One of the most powerful in the world was the National Aeronautics and Space Administra- tion (NASA) test reactor, located at Plum Brook Station in Sandusky, Ohio, near Lake Erie. From 1961 to 1973, this reactor was home to some of the most advanced nuclear experimentation in the United States. Engineer A. Bert Davis said of the work at Plum Brook, “We were young and eager and we felt like we were pushing back the fron- tiers of science.”3 The Plum Brook reactor became NASA’s nuclear frontier—the boundary between what was known and unknown about the effects of radiation on materials.