Oak Ridge’s Role in the Manhattan Project
William J. (Bill) Wilcox Jr. - Oak Ridge City Historian, Retired Technical Director for the Oak Ridge Y-12 & K-25 Plants, Manhattan Project Jr. Chemist, Y-12 Plant
What a colossal accomplishment that WWII Manhattan Project was! In an incredibly short 2 ½ years, it accomplished 3 missions, none ever before done anywhere: separation of the uranium isotopes (Oak Ridge), production of the element plutonium in large nuclear reactors (Hanford, WA), and learning how to put these materials together to make bombs (Los Alamos, NM). Ours was the costliest part of that project, and by far the largest in terms of the number of people required. Of the Project’s $2.2 billion cost ($26B or more 2008!), 60 cents of every dollar was spent here at Oak Ridge. 21 cents was spent at Hanford, 4 cents at Los Alamos. The scientific and engineering problems we faced here were forbidding not only in number, but in their complexity, and required inventions by scientists and engineers on a scale even now, hard to believe. In WWII, 22,000 people worked at Y-12, and cost of the isotope separation plants was $1B. The problem with depicting our efforts on a video for today’s public is our lack of drama, just a dogged day after day effort solving one new set of problems after another for 2.5 years with never a single day event as exciting or well-filmed for posterity as the marvelous Trinity test at Alamagordo!
Our 12-mile long, 6-to7 mile wide reservation here in East Tennessee was selected for the whole project 60 years ago just last month! Its code name during the war was Clinton Engineer Works, the name Oak Ridge was not widely used till after the war. The entire MP all over the country was administered from here, by Col. K. D. Nichols, the COO of the MP, who reported to Gen Leslie Groves who kept his office in Washington.
The number one mission for Oak Ridge was to separate the uranium isotopes – the two forms of uranium with slightly different weights that occur in nature. Back in 1939 when Hitler started WWII by invading Poland, scientists began kicking around the possibility that an atomic bomb with awesome power might be built if someone could just figure out a way to get a lot of nearly pure U-235, the lighter of the two forms of uranium that occur in nature. The heavier one is U-238, very little heavier. Isotopes can’t be separated like you separate iron from iron ore; they behave identically in all chemical reactions. You have to work with their trivial difference in weight, and that’s pretty small. Suppose we use two basketballs to represent uranium atoms, then the heavier U238 one will be identical except that it weighs the amount more that it will if you tape a five-cent piece to it! And then if separating them isn’t hard enough, U- 235 is scarce as hen’s teeth! In every 1000 pounds of uranium you dig out of the ground, there are only 7 lbs of 235 along with 993 lbs of U-238 –intimately mixed.
When the Manhattan Project started in the summer of 1942, Gen. Groves had three universities that had been researching separation methods for the last two years telling him: “Well, we think we know a way you might be able do it”. He was horrified by the uncertainty. By December 1942 he and his advisors reduced the field from three to two by stopping all work on one of the three ideas - the gas centrifuge (which interestingly 60 years later in 2002 is now the process of choice in the U.S.!). The scientists could still not assure him of the success of either of the other two: the electromagnetic approach and gaseous diffusion, so Groves decided they would have to go ahead and build both. The fear that the Germans might succeed with their efforts was the major driver.
Ground breaking for the first U-235 separation plant called Y-12 was in February 1943, and it was running in January 1944. Y-12 used over a thousand big devices called Calutrons in nine big buildings that produced separation when the uranium isotope mixture was driven through a very strong electro-magnetic field. After each had run a week or so it ran out of feed and had to be stopped, the little bit of product removed, recharged and restarted. The product was only partly enriched, so it had to be put through the process again to get bomb grade fuel and that’s where they needed hundreds of chemists like me. Those calutron magnets were enormous, and copper to wind their electrical coils with was in very short supply, so Y-12 borrowed silver from the U.S.Treasury to use instead of copper. They borrowed 14,000 tons of silver ingots worth more than $300 million to make the magnets, and after the war it was stripped it out and given back to the Treasury! The magnetic field was so strong it would jerk an ordinary wrench right out of your hand, or wreck the mainspring in your watch if you walked within a few feet of the machines!
Though almost all of Oak Ridge’s effort was spent on making U-235 for the first atomic bomb, code named Little Boy, we do have a tie with the Nagasaki plutonium bomb, Fat Man. The tie is through the Graphite Reactor, the world’s first real nuclear reactor, built out in Bethel Valley here and started up in November 1943. It’s purpose was to make small quantities of the new element plutonium so that chemists could find ways to handle it when they got the big production reactors running at Hanford.
Because Y-12 was not a sure-fire bet, Groves kept the heat on for the construction of a back up, another entirely new technology, and another $500 million plant called K-25 that employed a very different approach called gaseous diffusion. It sure sounded easy: all one needed to do was to make some gaseous form of uranium seep or diffuse through a porous, sieve-like membrane or barrier, and because U-235 molecules are a little lighter, they zip around a little faster than the U-238s so the diffused stream is slightly enriched. But the secret of how to make a really workable porous barrier had eluded scientists at Columbia Univ. who started working on starting in 1940! For one thing, all the holes in the membrane had to be microscopically small, so small that there could be hundreds of millions of holes in a sq. cm. (the size of your thumbnail) and they had to be all the same size, not too big, not too small or you get no separation. But even if you can make the perfect barrier, you get such a little separation each time it diffuses that you have to pump up the gas again and pass it through another barrier almost 3,000 times to get the purity of U-235 you need! That means we’re talking “big”. The gigantic K-25 building was 400 feet wide, a mile long, with 40 acres under roof- at that time the largest single process building in the world. It was chuck full of vacuum-tight pipes, pumps and tanks to hold the barrier, and is located out in the western end of our reservation.
K-25 started up in February 1945, a full year after Y-12 and it was to be months before useful enrichments would be reached, so K-25 contributed only in a minor way to ending WWII, but during the postwar arms race the plant was expanded again and again and continued to work superbly for many decades, not being finally shut down until 1985.
So much for what we did at the plants. What was life like after work? Believe me Oak Ridge in the fall of 1944 looked entirely different than it does now. Today our little city of 27,000 is a sleepy little town compared to the city of 75,000 that then ran full-throttle all night as well as all day. Our town then looked just like what it was – a big, brand new army base, built fast to do a particular job, not to last much past the war. The army engineers built miles of fences, guard posts, nearly 10,000 homes for families; 90 two story dormitories for 13,000 singles like me; 5,000 trailers, 16,000 hutments and barracks spaces for construction workers and soldiers, 2 Chapels (St. Stephen’s used each at one time or the other), 9 neighborhood schools, a hospital, rec halls, a dozen shopping centers, the eighth biggest bus system in the U.S.A., and all the rest. In addition to 75,000 residents in town, we had thousands of commuters and construction workers who came in for their three shifts.
One thing about our life any survivor will tell you about is what happened when it rained. Those things Tennesseans called “frog-stranglers” turned our thinly graveled roads into seas of sticky, slimy, slippery, shoe-sucking-off mud! And that accounted for one unusual feature of our town – its miles of boardwalks instead of sidewalks! At Y-12 I had to keep a clean pair of shoes to change to from the galoshes I wore in wet weather before going into the chemistry building.
And another memorable feature came from the fact that the land the Army bought here lies in two Tennessee counties that had “bone-dry” laws, meaning it was against the law to have any alcohol here! All we could buy was an almost nonalcoholic substitute called Barbarossa Beer! We had to smuggle booze in. There were shortages of whatever you really wanted, ration books, and long lines for everything! We singles went to all the movies at the Center Theater where the playhouse is now, and that meant four times a week, and went afterwards to the rec halls to jitterbug to big band records.
And always, in our plants and in town, there was an ever-present insistence on very tight security – don’t talk about what’s going on here! Keeping a secrecy rein on the people here was a real challenge. We routinely had security briefings at the plants and keep quiet slogans on all the billboards, but aggravating the problem was our short 13 miles to Knoxville where Ridgers fled to shop as often as they could. Ridgers outside the fence could be easily spotted from our muddy shoes, and you’d often get quizzed by friendly but so curious Southerners with questions along this line: “Gosh, that’s a huge operation out there, whatever are you guys making?” We got pretty creative in our answers. Some I remember were: ––“Oh, we’re just building a bunch of homes for all the officers to come retire in after the war.” ––“Hey, we’re making the front ends of horses to send up to Washington!” I heard that one guy said: “Shoot, I don’t mind telling you what I’m making out there– it’s $1.17/hour.” My favorite was the good ol’ Tennessee maintenance man at Y-12 who said: “Well, frankly I don’t know what they’se makin’, but I’ll tell you this much – the govmint could sure as hell go buy it somm’ers else a whole lot cheaper!”
I’m afraid none of our townspeople would have judged the huge Y-12 plant was a great success if they had been told that all of its product could be hand carried out by a couple of lieutenants each week! It was a relatively small amount, that highly pure U-235!
We made none of the Little Boy bomb parts here. All of Y-12’s wartime product was shipped out to Los Alamos in the form of fine crystals of U-235 tetrafluoride, a pretty blue-green powder! No, it does not glow in the dark! Its radioactivity will not penetrate the skin, so you can safely hold several pounds in your hand, but it sure was precious. It had cost about 250 thousand dollars an ounce to make it! We packed it into a container about the size of a coffee cup made out of nickel and heavily plated with gold on the inside so the costly green powder would not get contaminated and then have to be re-purified by Los Alamos. After putting on covers, two of these cans were packed in a wooden frame in a very ordinary looking leather attaché bag like businessmen carried in 1945. This super valuable briefcase was then chained to the wrist of a lieutenant in military security wearing civilian clothes and off he went off with armed escorts by train to Chicago and then took the Santa-Fe Chief out to New Mexico where they carefully made it into one of the two bombs that helped end WWII in August 1945. In the early spring of 1945 Y-12 was finally operating smoothly like everyone had hoped it could, finally sending nearly pure U-235 to Los Alamos. They experimented with it and over the next months accumulated enough to make the metal parts for the gun-type atomic bomb – where a uranium bullet was fired down a gun barrel into a uranium target, very rapidly creating a supercritical mass that resulted in the chain reaction and atomic explosion. The last parts were finished in July and carried out to Tinian Island in the Pacific, where the bomb was assembled and ready by August 1st, meeting Groves near impossible target. Weather kept it from being dropped till August 6th.
I’ve often been asked, “Why was the Manhattan project so successful?” First on my list is the fortunate selection of the tough, brilliant Gen. Leslie R. Groves to run it and our government’s wise decision to put the entire mission, scientists and plant building and operation under him. Second, Groves’ enlistment of the very best companies to design, build and operate the never before heard-of giant facilities. And other key factors in success were the availability of money (almost a blank check); the top wartime AAA priority Groves finagled so they could get the things they needed in the wartime when every thing was in short supply; and then the great emphasis on secrecy that worked to speed things up – no-one had to spend anytime briefing Congress, each other, the public or any other stakeholders.
But, you know, I believe the most important reason so much got done so fast was that everyone from Gen. Groves on down to the operators on all three shifts had a common purpose – to do whatever each could seven days a week to help end the war. Nobody ordered us to work extra long and extra hard; we instilled that in ourselves by reading the papers each day and hearing on the radio every night of the atrocities and the killing of our countrymen and allies in North Africa, on the beaches in Normandy, on the infamous Bataan Death march in the Philippines, in the jungles of Burma, and on islands in the Pacific whose names we had never heard before, and now can never forget. This is what is so hard to get across to the next generation. I’ve had a hard time describing it to my own kids– that patriotism that made you work so hard, keep secrets, put up with the shortages, and live with rules you often did not understand. Everyone wanted “to help win the War”.
Our country glimpsed a kindred spirit in a few weeks following the horrific attacks of September 11, last year, an outpouring of that patriotic feeling: “What can I do to help?” But during WWII we read about awful horrors somewhere week after week for six long years. (1939 to 1945) A million American boys were killed or wounded in the three years and nine months our Nation was at war. I lost my best boyhood friend who was piloting a bomber over Germany; both of my wife’s brothers were in the Services, almost everyone you worked with knew someone who had lost family members.
So how did we here in Oak Ridge react when we heard about those two atomic bombings that marked the success of the Manhattan Project? Well with the same incredible surprise of the rest of our country! Nobody I knew felt any glory in the deaths of the 100,000 Japanese at Hiroshima any more than we gloried in the deaths of about that same number in the fire-bombing of Tokyo a few months before on the night of March 9/10th––a bombing that burned out 16 square miles of Tokyo, 4 times the area burned out at Hiroshima. No, what we did take pride in was that the shock of the Manhattan Project’s success had finally caused their reluctant Emperor to stand up to his die-hard militarists and insist on bringing to an end the War they started against us at Pearl Harbor. And that great pride in the success of our efforts turned to exuberant joy a week later when we Oak Ridgers awoke the morning of August 14th to see the headline in our Knoxville newspaper. That landmark edition was printed on red paper and carried an 8-inch tall banner headline: P E A C E !
That six year World War that we helped stop had involved a nearly incomprehensible total of 54 million people killed by other humans, and the blessed peace all of us had worked and prayed so long and so hard for was at last a reality!
Shortly after the war, I’m proud to say Oak Ridge led the way in making peaceful applications of atomic science using our Calutrons and our Graphite Reactor to produce radioactive and stable isotopes that have brought the world so many benefits in medicine, agriculture, and industry; benefits we still enjoy today. And later Oak Ridge again led the way in giving to the world nuclear research reactors and then nuclear power plants whose clean electric power - though not yet embraced by the public in this country - has been welcomed and beneficial to so many countries of the world including Japan, our war-time enemy but for a half century since, good friends. These peaceful uses of atomic energy together with the blessed freedom from WWIII for well over half a century, – these are our rich legacies of the Manhattan Project.
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December 14th, 2009
