An excerpt from the new book, “U.S. Nuclear Deterrence: The Cold War and Colorado’s Nuclear Weapons Factory” by Farrel Hobbs. (Coming Soon to Amazon.com bookstore by Sept. 15, 2018.)
Let’s start at the beginning, which, in the case of Rocky Flats, is about 4.5 billion years ago. The Rocky Flats Plant was known mostly for its role in producing plutonium components for nuclear weapons. Those of us who worked there knew that the plant did much more than that; many thousands of people who worked at the plant never came close to any plutonium. However, plutonium is what comes to mind for most people when they think of Rocky Flats. Activists who devoted themselves to protesting the place learned that they created more support against the plant when they focused on plutonium, and they began to declare that “plutonium was designed to kill.” That’s a very catchy phrase, but there weren’t many people around to be killed 4.5 billion years ago when plutonium first existed on Earth. I restrict my discussion to Earth and ignore what possibly happened in other galaxies.
What is “Natural Plutonium?” Scientists working where uranium was being mined in the Gabon Republic in Africa realized there was something unusual about the isotopic concentration of the ore in what was called the Oklo uranium deposit. “In May 1972 a worker at a nuclear fuel-processing plant noticed something suspicious. He had been conducting a routine analysis of Oklo uranium from a seemingly ordinary source of ore. As is the case with all-natural uranium, the material under study contained three isotopes.” The analysis found there was less uranium 235 — the isotope required for running nuclear reactors and making nuclear weapons — than expected. The ore was far short on uranium 235; some 200 kilograms appeared to be missing. That was enough to make half a dozen or so nuclear weapons.
That statement is likely to pique the interest of most who are interested in the argument for and against the development of nuclear weapons. For those who oppose, did someone use the uranium deposits to secretly extract the uranium 235 to build a half dozen or more nuclear weapons? Or, if you aren’t in that camp, what happened to the uranium 235 that should have been in the deposits? The answer is that nature found a way to create “natural reactors” that converted the uranium 235 in the Oklo uranium deposits into plutonium along with other reaction products.
That statement is likely to pique the interest of most who are interested in the argument for and against the development of nuclear weapons. For those who oppose, did someone use the uranium deposits to secretly extract the uranium 235 to build a half dozen or more nuclear weapons? Or, if you aren’t in that camp, what happened to the uranium 235 that should have been in the deposits? The answer is that nature found a way to create “natural reactors” that converted the uranium 235 in the Oklo uranium deposits into plutonium along with other reaction products.
P.K. Kuroda is the person often mentioned in explaining the discoveries at Oklo. His book, The Origin of the Chemical Elements and the Oklo Phenomenon, describes how, as a 19-year-old student in 1936, he saw a notice that Nobel laureate Francis W. Aston was going to present a lecture on isotopes at the Imperial University of Japan. Kuroda purchased a technical book by Aston to prepare himself for the lecture and “was thus introduced to the field of Nuclear Chemistry.” Kuroda observes in his book that nuclear chemistry was destined to have a profound influence on the ultimate fate of his native country of Japan and his future career as a scientist.