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The Secret City
Most of us have some idea of the history of the atom bomb, or at least think that we do. The Manhattan Project was a huge undertaking. Some estimates put it's cost at up to a quarter of the total defense budget, during the war. In today's dollars, the project would cost something like 26 billion dollars. And this was just the beginning. What we got for our money was four nuclear warheads, out of which three were detonated to end the war (Trinity, Hiroshima, Nagasaki). So we essentially ended WWII with one atom bomb, huge worldwide responsibilities, and the seeds of the Cold War. Untold effort was expended to further develop nuclear weapons, and the platforms by which they are carried and launched.
This project was to be so complex, and uncertain, that it would ultimately be carried out in various locations, around the country. From the busy streets of Chicago, to the desert of New Mexico, as well as the far western banks of the Columbia River in Washington State, and the quiet hills of Tennessee. Near the town of Knoxville, was a seldom visited, and somewhat out of the way place, called Oak Ridge. There were some farms there, as well as hills, a few small farm communities, and miles of open space. The nearby dams of the Tennessee Valley Authority provided the huge amounts of electricity, which would be needed for this part the project. Initially, this was to be the location of the entire project; but this was soon found to be impossible. Eventually, two other top secret sites were built, one at Los Alamos New Mexico, and one at Hanford Washington. Even so, the Oak Ridge site continued to be the headquarters, as well as the largest facility, by far. Though the mission of the place would be expanded after the war, the eventual war time mission here was one simple thing. Uranium was to be separated out into it's very active 235 isotope. This isotope was then to be taken to Los Alamos, where once gathered in sufficient quantities, it would be assembled into a bomb.
In addition to the isolation, and abundant electricity of the site, Oak Ridge also had a unique geography, which served the needs of the project very well. This is an area of long ridges separating flat valleys. The three major portions of the facility were the Y-12 electro magnetic separation plant, the K-25 gaseous diffusion plant, as well as the X-10 reactor complex, and then the city itself. These were separated by ridges, and each occupied it's own little valley. This served a couple of purposes. It made secrecy a bit easier to maintain, and also served to protect the areas from each other, in case of a serious mishap.
There were no bombs made here, no scientists laboring over their chalkboards, papers, and the primitive computers of the day. Most of this was going on at Los Alamos (latter to be renamed Sandia), or the University of Chicago (metallurgical laboratory). The one and only function of Oak Ridge was to provide quantities of relatively pure U235. The U235 was to be used to directly make bombs, such as Little Boy, and also to indirectly make bombs, through plutonium production. It was the one absolutely essential material. This simple task turned out to have monumental complications. U235 makes up .7% of naturally occurring uranium. The rest is U238. the two can not be chemically separated. The only way to increase the proportion of U235, is to separate it by weight. It weights 1.5% less than U238. In addition, uranium is a solid, hard, and very heavy metal. As a matter of fact, once the isotope is purified, as our anti nuke friends continually like to tell us, the rest of the task of making a nuclear warhead is simple. This is wrong, as are most of the tenets of the left; but those who so believe, are correct in determining that the purification of the isotope is the sticking point, and the largest single obstacle to be overcome. Even so, they rarely allude to the fact that getting the isotope purified is an exceptionally difficult, and painfully time consuming process, particularly at the beginning.
There were two main methods of separation used here. The first was magnetic separation, and the second was by gaseous diffusion. The magnetic separation method required the uranium to be vaporized, and then run through a magnetic accelerator called a Calutron. In the Calutron, a magnetic field swung the uranium atoms around a "racecourse" Heavier and lighter atoms were carried out to different distances by their weight and inertia. It was possible for scientists to calculate how far a magnetic field of a certain strength would carry an atom of a certain mass. They could then place collection stations at appropriate sections of the racecourse.
The gaseous diffusion method required dissolving the uranium in acid, chemically combining it to make uranium hexafluoride, which is a gas, and then running the gas past porous membranes at high temperatures, and elevated pressures. Every time this was done, just a tiny bit more 235, than 238 got through, due to the difference in weight. After thousands of cycles, some significant enrichment of 235 would be seen. As it was produced, and associated with Oak Ridge, U235 came to be known as Oralloy, while natural uranium was called tuballoy. Plutonium, which was produced here in small quantities, came to be know as "copper", while actual copper was called "honest to God copper".
My own visit to Oak Ridge was during the Secret City Festival, towards the end of June. I saw the reactors, toured the countryside, and learned a few things, from the multitude of special exhibits, and activities staged for the event. This year, the even was held on the weekend of June 21-22. This is an outgrowth of an arts and crafts festival that has been held since the early eighties. In 2002, the city decided to enlarge the festival, integrate some of the area's nuclear heritage into it, and hold the festival latter in the summer (it had originally been held in May). I strongly advise anyone with any interest in the subject, or simply anyone looking for an enjoyable visit to someplace other than the manufactured tourist destinations, to visit here during the festival.
During the Manhattan Project, what was then known as the Clinton Engineering Works, was broken up into three sections. There was Y12 , where the electromagnetic process used calutrons to separate U235, from U238, then there was the K-25 gaseous diffusion plant, as well as the X-10 reactor and purification plant, for the production of plutonium. All were surrounded by a huge fence, and extensive security system. All were separated by the ridges which mark the countryside here, so that if disaster should occur only one section of the project would be destroyed. All still exists today, though in somewhat changed form. The city is still there, still growing, and today is a wonderful place to live. The old K-25 gaseous diffusion plant is in the process of being partially dismantled, though it is hoped that the uncontaminated sections may be kept and transformed into an industrial park. The old Y-12 Calutron section is now the weapons assembly and refurbishment plant. X-10 is presently the Oak Ridge national Laboratory, doing a variety of nuclear, and non nuclear work.
Oak Ridge is the Mecca, the Holy Grail, and the ultimate pilgrimage, for the nuclear tourist. This is the place where it all started, and is still the center for nuclear research, weapons manufacturing (and refurbishing), storage of nuclear materials, and production of nuclear materials. All other nuclear sites, developments, and applications are mere outgrowths of this place. It is the center of the nuclear universe. At the present time, all United States nuclear materials are stored here, and all United States nuclear weapons are manufactured or refurbished here. An entire valley, which is filled with the Y-12 National Security Complex, is dedicated to the mission of maintaining our nuclear arsenal. K-25 is being decontaminated, and it is hoped that parts may be preserved as a monument, and that other parts may be reused as part of an industrial park. The laboratories, and headquarters are now the Oak Ridge national Laboratory, and are used for research in a number of different areas. This section is similar in purpose to the Argonne national Laboratory (which also got it's start as part of the Manhattan Project), and Fermi National Accelerator Laboratory (Fermilab).
In many ways, what happened here was stranger than any fictional spy novel , or adventure story. By the end of the war, this was the fifth largest city in Tennessee, and had over 75,000 inhabitants, and yet was not shown on any map until 1949. Because it didn't exist, the town did not have a mayor until 1951. The entire 60,000 acre compound was fenced, and guarded, including the city itself. Everyone who lived there, over the age of 12, was required to wear a badge at all times. Everything, and everybody, going in and out of town, was required to pass through one of six gates. People were not to talk about what they did, to anyone, even their fellow workers. Everything was compartmentalized, and only half a dozen people knew what was actually going on at the facility.