ABriefHistry-ApprvdforRelease03-12-08

A Brief History of K-25 Approved for Release by K-25 March 12, 2008

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A BRIEF HISTORY OF K-25The Biggest Secret City Secret

William

(Bill) Wilcox, Jr.

J.

Retired Technical Director for Oak Ridge K-25 & Y-12 Plants 1968-1981 Appointed Oak Ridge City Historian by City Council, June 2006

An Enlarged Compilation of the Series of 18 Articles on the History of K25 Appearing in the OAK RIDGE OBSERVER from February to June 2006. With Additional Photographs and Commentary

The Secret City Store Oak Rdige, Tennessee December 2007

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A Brief History of K-25

The brand new and highly secret K-25 Plant in 1946. The construction infrastructure has not yet been cleared away. The huge U-shaped building (in this photo seen from the open end) dominates the site along with its essential gaseous diffusion equipment assembly building, K-1401. That building, which was 400 feet wide and 1,000 feet long, is at the right of the "U" in the photo. Running across the foreground is the old Gallaher Ferry Road, near where State Highway 58 now runs. Below to the right is the western end of the J. A. Jones Co. construction camp called Happy Valley, which stretches from this point all the way up to the right past Blair Road. The photo was likely taken in the summer of 1946 after completion of K-27, at the left below the "U" building. Another clue to the date of the photo is that some of the 16 feet x 16 feet hutments at Happy Valley have been demolished, having served their purpose. The large building just this side of the highway was one of the Mess Halls." More than 12,000 construction workers and their families lived in "Happy Valley" because housing was not available for them in Oak Ridge. Aerial photograph by J. Edw. Westcott, courtesy Oak Ridge Public Library.

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Book Copyright 2007, Wm. J. Wilcox, Jr. FOREWORD About five years ago when I was finishing up my Chronology of Noteworthy Events and Contributions of the Y-12 Plant, I saw the need for a similar accounting of the also largely unknown and underappreciated contributions of the Manhattan Project's largest plant, K-25. I developed the outline, not for just a Chronology like the one I did for Y-12, but for a full history and began research for it. Mr. Steve Leidle of BJC kindly initiated a reinstated clearance for me so I could use the archives at K-25, but about the time my research got well underway, the issues of historic preservation at K-25 moved to the foreground of DOE-ORO EM concerns and my hours were soon devoted to making the case for saving a part of that historic relic so book research stopped. My first proposal to ORO for saving something involved saving a part of K-29, turning 30 or so cells with their vault space into an Oak Ridge Technology Museum that would show and tell K-25, Y-12, X-10, S-50 and Gas Centrifuge technology. ORO said no. By then our ORHPA Group had gotten behind the K-25 preservation project on behalf of the Community. ORO called in an A/E (EE&K) experienced in historic preservation to get an outside recommendation. Their ideas proved too costly so we stepped our efforts trying to come up with a reasonable yet useful solution. A year later we had it namely saving the North End building and marking and saving in perpetuity the footprint of the original buildings. This was formalized in the MOA of March 2005 agreed to by DOEORO, the State, the Advisory Council on Historic Preservation, and concurred in by the City of Oak Ridge, and ORHPA. Early in 2006, as part of our effort to engage the Oak Ridge community behind our efforts, Ray Smith suggested a series of newspaper articles to introduce the public to K-25's history (see next page). Stan Mitchell of the Oak Ridge Observer agreed the series extended for 19 weeks. I had many requests for a collection, and this document is the result. I have elaborated the text, added a number of photos, and have added several appendixes that I had prepared for the "book," namely a chronology of noteworthy events and dates, and a listing of our "bosses" of the Oak Ridge and Paducah plants that may be of interest. I include a list of the primary references from which I have drawn the stories and history. I was employed at Y-12 during K-25's research, construction, and first four years of operation, not transferring to K-25 until Jan 1, 1949. Then all my subsequent work experience was in the Lab and Technical Divisions: I have depended on the written texts (especially Lagemann, and Jones) and on many friends like Joe Dykstra, Bob Dyer, and many others for my accounts. This then is not a documented, official history, but rather a story for the general reader that I hope will result in people developing some appreciation for the monumental achievement wrought in Oak Ridge's backyard in secret and in haste in World War II that made a major contribution to the nation in the years since which, because of secrecy and forbidden access has never before been properly appreciated. We hope to save a small portion so you and future generations can come visit and see it for yourselves.

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Bill Wilcox, Oak Ridge, December 2007. PREFACE "Introducing a new and unique history series" The above heading served to begin a journey that would for months draw me even closer to my good friend and fellow historian, William J. (Bill) Wilcox, Jr. Bill had asked my opinion regarding a task he desired to undertake: present the history of the K-25 Plant in Oak Ridge, Tennessee, in a form that would interest the general public. Most people are unaware of the remarkable contributions K25 made not just during World War II but also over the half century since. I suggested a series in the local weekly newspaper, the Oak Ridge Observer, primarily because of the success I recently had with Stan Mitchell, the publisher, who had printed several of my articles about Jack Case, the long-time manager of the Y-12 Plant, the first huge Manhattan Project plant in Oak Ridge. I am pleased to write this foreword for the edited compilation of those 19 weekly newspaper articles. When this massive facility was built in 19431945, its heart was the single largest building under one roof in the world. At the time K-25 also had the worlds largest steam-generating power plant to help the Tennessee Valley Authority provide electricity for K-25s operations. Because of the importance of K-25 to national security in the 20th century, the remarkable history of this facility needs to be told to a new generation of citizens. Freed here from the newspapers weekly space restrictions, Bill has included more history as well as many more photographs in this document. You will leave this series appreciating the basic principles of gaseous diffusion and the remarkable engineering effort required to produce nuclear fuel enriched in fissionable uranium-235 to the high levels needed for nuclear weapons and the low levels for nuclear power plants. You will gain respect for the leaders, managers, and scientific and technical professionals who applied a variety of skills to the successful operation of the K-25 complex until 1985. As an active participant at K-25 since 1949 (he was at Y-12 during WWII), Bill provides a unique perspective, helping the reader understand why he and so many other K25ers feel great pride and a tremendous sense of accomplishment in their work at the plant. Bill also tells the more recent story about the activities in which he, I, and many others are involved to preserve a portion of the Historic K-25 U building. Through our planned historical tourism attraction we hope to tell future generations about the tremendous scientific and technical achievements of the people who designed, built and operated the K-25 complex. We also hope A Brief History of K-25 will help Americans and particularly Oak Ridgers understand the importance of preserving our City's unique heritage because of the

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important lessons history teaches and because of the potential economic value of heritage tourism. D. Ray Smith Oak Ridge, Tennessee September 20, 2006

TABLE OF CONTENTS Page Frontispiece Foreword Preface... Table of Contents 7 Chapter 2 The Big Idea (Research Beginnings) 11 Chapter 3 Formidable 14 17 Problems in Plant Design ... Chapter 4 Kellex Tackles K-25 Plant Design 20 Chapter 6 - Oak Ridge's Lost City 22 Chapter 7 Oak Ridge's Lost Plant 26 Chapter 8 - Equipping the K-25 "U" Plan 31 Chapter 9 Starting-Up 35 the Mammoth Plant. The 2 3 4 5 Brand New K-25 "U" and its Support Buildings,

1946.

Chapter1 - A BriefHistory, In Brief.

Chapter 5 - Construction of the Mammoth Plant

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Chapter 10 Operating at Last Smooth Sailing 40 Chapter 11 Time-Out 46 for Two "Urban Legends" 50 Chapter 13 But, Is there A Better Way the Enrich 61 Uranium?......................................... .... 56 Chapter 14 - A New Day 64 Chapter 16 Forty Year of Service Ends 68 Chapter 17 The Decades 73 of the 1990s and 2000s 76 Primary References Consulted 78 Acknowledgements 81 Appendix - The Top Officials 1943 to 2000 85 80 Appendix The Costs of K-2 5 and the Manhattan Project during the War Years . Chapter 15 - K-25's Bright 1970s

Chapter 12 "Mothering" the Great Expansion

Chapter 18 Will They Be Able to Know and Remember ?

A BRIEF HISTORY OF K-25:The Biggest Secret City SecretWilliam J. (Bill) Wilcox Jr.

INTRODUCTION

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-25 was the largest and most costly building of the entire Manhattan Project, not just of Oak Ridge. But in terms of importance, the biggest secret 75,000 Oak Ridgers kept from 1943 through most of 1945 concerned all of the frenetic activity under way behind our Clinton Engineer Works fenceour part in the race to beat the Germans to the atomic bomb. K-25 was built to be a backup plant to the Y-12 Plant, General Groves' choice as the plant most likely to deliver the critical highly enriched uranium. But there were lots of questions about its technology, hence the decision to also go ahead with K-25 in case Y-12 ran into trouble. Both were half-billion-dollar, first-of-theirkind plants. Each was a tremendous scientific and engineering achievement. Only the original World War II K-25 "U" building still stands full of its equipment, just now in the process of being decontaminated, decommissioned and demolished in a complex process Oak Ridgers have been hearing about for years. Because K-25 is a one-of-a-kind historic gem, residents of and visitors to Oak Ridge may be interested in learning some of that facilitys remarkable history. This paper is an informal overview of the history of K-25 telling some of the story about the development of this World War II project from the initial idea to the huge industrial complex that responded over 40 years to its national missions in war and peace. While working at K-25, I had occasion to take many official visitors on plant tours. Visitors were awed not just by the plants vast size, but by the fantastic technical achievement K-25 represented. Of course, after being shut down in 1965 and exposed to winter's cold and summer's heat for 40 years, the K-25 U building has suffered from neglect, but its essence is still there. Paul Parson, former reporter for the Oak Ridger, talked his way into getting a private tour inside the K-25 "U". He had to dress out in an uncomfortable Tyvek suit, face mask, and multiple booties and gloves before being allowed to enter one of the equipment Alleys"now dark, cold, moldy, mildewy, and very dirty. Nevertheless, he had the same view of the gaseous diffusion equipment that General Leslie R. Groves, the Army commander of the Manhattan Project, had in the 1945. Paul was able to envision the buildings original appearance despite the decay of 40 years. He headlined his upbeat newspaper report on his visit, Amazing! We expect future visitors to have the same reaction after a small part of this historic relic is cleaned up and restored so they can visit it. Oak Ridgers have grown so accustomed to living with this elephant in our back bedroom that many dont realize that K-25 is, indeed, a national treasure. Our Tennessee Historic Commission's Dr. Joseph Garrison in 2007 rated K-25 as the top historic asset in Tennessee. Cities and towns all over the United States are turning to heritage tourism as an additional and important economic development income stream, and K-25 can add to that for Oak Ridge. Oak Ridge has two really unique stories to show and tell that no other place in the world can. First is our World War II Manhattan Project story about Y-12, K25, X-10, and S-50 and the Secret City the 75,000 lived in. Second is our story of

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the legion of beneficial applications of nuclear science and technology discovered by Oak Ridge researchers over the years since the war. Radioisotopes and stable isotopes produced in Oak Ridges X-10 nuclear reactor and in Y-12's calutrons made possible the birth of nuclear medicine for both diagnosing and treating cancer and other diseases. Then our ORNL's novel reactor designs coupled with low-cost enriched uranium fuels from K-25 made possible economic civilian nuclear power which produces 16 percent of the worlds electricity. Oak Ridges isotopes and ingenuity brought benefits to people alanl over the world through improved agricultural productivity and industrial measurement technology. K-25 played the major role in building the nation's U-235 stockpile after WWII that helped win the Cold War, and Y-12 has been an integral part of the national nuclear defense system keeping the world free from World War III for over half a century. I hope that these chapters, based on a series of articles previously published in the Oak Ridge Observer, will enlighten readers about K-25s role in Oak Ridges remarkable history. Here now is a short summary of that history.

CHAPTER 1THE BRIEF HISTORY, IN BRIEF

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onvinced that our country must be the first to find a way to build an atomic bomb, President Roosevelt in 1942six months after the Japanese surprise attack on Americas naval station at Pearl Harbor, Hawaiiturned that enormous challenge over to the Army Corps of Engineers. The national Manhattan Project that the Army engineers organized devoted the largest part of what turned into a $2.2 billion effort on the construction and operation of two, first-of-a-kind plants at Oak Ridge, Tennessee whose mission was to produce nearly pure uranium-235 (U-235), the lighter of two forms of uranium that occur in nature. This rare U-235 form, one of the three naturally occurring forms, 1 splits into lighter elements and releases huge amounts of energy and more neutrons when bombarded with neutrons. It was this rare form that was needed to build an atomic bomb. Never before had anyone tried to separate U-235 from U-238 in pound-size amounts, and none of the top scientists could be sure they could separate these two isotopes in time to affect the outcome of the war. But knowing that the Germans were trying to make an atomic bomb and that Adolf Hitler, Chancellor of Germany, would not hesitate to use such a weapon if he got one, the top U.S. government officials agreed that Americans had to give our best effort to the challenge of developing the worlds first nuclear weapon. December 1942 was a landmark month for the Manhattan Project. On Dec. 2, 1942 Enrico Fermi and his team demonstrated the first nuclear chain reaction at the University of Chicago. The researchers showed that when uranium are split1

Natural uranium consists of 99.23% U-238, 0.7115% U-235, and 0.06% U-234. That is to say there are 139 times as many U-238 atoms as there are U-235. 8


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by slow neutrons neutrons they emit new neutrons, the reaction sustains itself and can be controlled. Other critically important events in December 1942 were the decisions made by Gen. Leslie R. Groves, the Army brigadier general who directed the Manhatttan Project and his technical advisors. They had to select one of the four most promising U-235 separation process ideas they felt was the surest and quickest route to an atomic bomb. Their choice was the electromagnetic process proposed by Prof. E. O. Lawrence of the University of California at Berkeley. It was far from being a "slam dunk" procees the plant was going to require more than 1,000 calutrons, complex, new physics machines with powerful electromagnets, not one had ever been made. And they would have to work in a start-and-stop, batch-wise mode requiring thousands of employees. This electromagnetic method of separating U-235 from the more abundant U-238 isotope was the basis for the first-ever uranium enriching plant in the world, code named Y-12, and operated by Tennessee Eastman Corporation. At its peak, Eastman employed 22,400 workers and was Oak Ridges chief employer during World War II. Y-12 sent Los Alamos all the U-235 needed for the first of the two atomic bombs that helped end World War II. Y-12 cost $478 million, in 2007 dollars more than $5.4 billion. The mission of the Manhattan Project to beat Germany to the bomb was so urgent that Groves and his top policy advisors decided they could not risk betting everything on Y-12. They decided to build a backup plant using gaseous diffusion, the second most promising approach. This process was the brainchild of Columbia University scientists in New York City under Prof. John R. Dunning who began researching it in 1940. The backup plant, given the code name K-25, was built on the flattest part of the area at its western end where the Wheat Community existed before the Army moved in. It followed along almost a year behind Y-12. The construction of K-25, including its powerhouse, cost $512 million, at least $5.8 billion in present-day (2007) dollars. K-25 was a tremendous engineering achievement built in the midst of World War II. Separation of uranium isotopes by gaseous diffusion involves a basically simple step (called a stage) of pumping about half of a uranium gas stream (the feed stream) through a very fine pored membrane (called a barrier). Because the gas molecules containing the U-235 are a little lighter that those containing U-238, they move a little faster so if the holes are small enough, the diffused gas will be slightly richer in U-235 while the stream that goes straight through without diffusing is slightly depleted in U-235. Sounds easy? But the amount of separation achieved in one step is so small that to get

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the nearly pure U-235 needed for a nuclear weapon or to drive a submarine this diffusion step must be repeated over and over again through a long series of more than 3,000 of these stages, the whole affair called a cascade. The 3,000 stages in the K-25 "U" building each have two electric motordriven gas pumps or compressors and a gas cooler, so this turns out to be an enormous undertaking in size, in cost, and in technical complexity. Construction of the 44acre, milelong, "U" shaped plant, four stories high and up to 400 feet wide, posed many new problems for design engineers, construction contractors and later for the bicycleriding plant operators. New lubricating and coolant materials had to be invented that would withstand the extremely reactive and corrosive nature of UF6 gas. The hundreds of miles of steel piping all had to be protected by pinhole-free nickel plating. All that process piping had to be welded together as vacuum-tight as a thermos bottle, to prevent any in-flow of air which would introduce (because of its humidity) moisture that would instantly decompose the UF6 gas into a fine yellow powder that would plug the tiny holes in the diffusion barrier and bring the whole process to a halt.

The building has four stories. Trucks can drive into the first floor from the roads around the outside of the "U", and right into the second story from the roads on the inside of the giant "U" building. The building is about 62 feet high on the outside, 45 feet high on the inside, or said another way the "courtyard" road is 17 feet higher than the surrounding roadways. Because the operators perform all their work on the top floor, only it has any windows. The total area under roof or the footprint, is a little over 44 acres (nearly 2 million sq. ft.), making the K-25 U building the largest building of the Manhattan Project. This 1946 or 1947 photo is from the Oak Ridge Public Library's Westcott Collection.

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Parts of the great K-25 "U" building were started up in the spring of 1945, surprising many and relieving everyone by operating so well. Near the end of 1946, highly enriched U-235 was produced for the first time. The good news for K-25 workers was that K-25s continuous process produced highly enriched uranium at less than a tenth of the cost to make it using Y-12s batch process so it would now be the source of that vital material for our national defense. This was not happy news for Y-12 workers because at the end of 1946 all the Y-12 calutrons were shut down and during 1945 and 1946 20,000 Y-12 workers lost their jobs. This year-long layoff was Oak Ridges biggest ever. That huge loss of jobs was the major reason why our citys population dropped from 75,000 to around 30,000 a little below which it has hovered ever since despite some large new government programs coming and going. The K-25 "U" continued to operate smoothly and provided the base for a major expansion of U-235 production capacity during the U.S. arms race with the Soviet Union that began in 1949. That was the year when the U.S.S.R., in August, exploded its first nuclear device, a "carbon copy" of our Trinity shot at Alamagordo, New Mexico, four years before. In 1964, after producing highly enriched U-235 for 17 years many thousands of times more than was made during WWII the federal government decided enough nuclear fuel had been produced to meet our future defense stockpile needs. As a result, the World War II K-25 "U" building was shut down, and the rest of the newer gaseous diffusion buildingsK-27, 29, 31, and 33 then began meeting the peacetime mission of producing only "low-enriched" (3 to 5%) U-235 fuels for the free-worlds civilian nuclear power reactors. During the 1960s and most of the 1970s, the United States had a virtual monopoly on the world market for enriched uranium. However, as foreign countries began to rely increasingly on nuclear power, they also entered the enriching business. Always looking for ways to cut costs, K-25 technologists and engineers in 1960 started researching the process of separation of uranium isotopes using gas centrifuges pioneered by Prof. Jesse Beams at the University of Virginia. In 15 years they developed a commercially successful gas centrifuge process that uses just a small fraction of the electric power required by gaseous diffusion. In the 1970s K-25 and Y-12 technologists also began helping the two weapons labs develop still another potentially low-cost enriching method using lasers. The Department of Energys Lawrence Livermore (CA) National Laboratory developed the atomic vapor laser isotope separation (AVLIS) method, and DOEs Los Alamos (NM) National Laboratory developed the molecular laser isotope separation (MLIS) process. In the 1985 DOE decided to end the diffusioncentrifuge-laser competition and focus all research and development work on lasers (AVLIS), which was argued to hold the most promise for low enrichment costs. DOE stopped all further work on MLIS, on advanced gaseous diffusion, and on the gas centrifuge process.

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Finally, with decline in the U. S. market share for enriched uranium, the U.S government decided in 1985 that the K-25 site had served its purpose and ordered all the diffusion facilities to be placed in standby. Three years later DOE changed this order to "shut it down." Since that time planning has been under way for the decontamination, decommissioning, and demolishing (D&D&D) of the old facilities with a vision of re-industrializing the site by leasing some of the better buildings to the private sector. In connection with this planning process (and as mandated by the National Historic Preservation Act) DOE has been conducting studies to determine what needs to be done at K-25 to meet historic preservation requirements. Throughout 2004, 2005, and 2006 DOE hosted a series of meetings with interested stakeholders, including representatives of the Oak Ridge City Government, the Oak Ridge Heritage & Preservation Association (ORHPA), the Local Oversight Committee, the State of Tennessee's Historical Commission, the Advisory Council on Historic Preservation in Washington, and DOE Headquarters. The participants forged an agreement in 2005 to preserve not only significant artifacts, but also the North End buildingthe connector between the K-25 buildings two long legs. ORHPA has developed both a passion and a comprehensive plan for making this national and State treasure a heritage tourism destination that will really appeal to future generations, helping them understand and appreciate the monumental achievement wrought by their forefathers in this beautiful East Tennessee countryside in the midst of World War II.

CHAPTER 2THE BIG IDEA (Research Beginnings)

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o where did the idea for K-25 come from? The seeds of the Manhattan Project were planted late in 1938, a year before Adolf Hitler started World War II, when two German chemists, Otto Hahn and Fritz Strassman, discovered that uranium atoms could be split making two smaller atoms when bombarded with neutrons. Austrian physicist Lise Meitner with her nephew Otto Frisch, both refugees from Nazi Germany provided the first theoretical explanation of the nuclear fission process. Physicists all over the world rushed to their labs to confirm their work which was not secret, but published for all to see. Physicists everywhere soon learned that the splitting (fissioning) was accompanied by the release from the nucleus of more neutrons and tremendous amounts of energyten million times the energy released in chemical reactions like burning gasoline or exploding TNT. At Columbia University in New York City, John R. Dunning, an experimental physicist, joined in the early theoretical discussions of nuclear fission with Enrico Fermi, Leo Szilard, Edward Teller and occasionally Eugene Wigner of Princeton University (who later directed research at Clinton Labs, later the Oak Ridge National Laboratory). Dunning led a team that repeated Hahn and Strassmans experiments and obtained the same results.

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As the result, Dunning grew more and more interested in the possibility that the process could be used to make a new military weapon. He urged his colleague Prof. Alfred O. C. Nier at the University of Minnesota to employ Nier's newly improved and perfected mass spectrometer to separate microscopic amounts of uranium isotopes. In 1938 Nier had used that instrument to analyze natural uranium; and had found that for every 139 atoms of U-238, only one U-235 atom is present. By the end of February 1940 Nier learned how to produce the tiny but pure amounts of the different uranium isotopes Dunning needed. He sent Dunning through the mail a handwritten letter onto which he had pasted three small pieces of nickel foils, each containing a microscopic amount of one uranium isotopeone with U-234, one U-235, and the other U-238. Dunning received his history-making Special Delivery letter on Friday, March 1, 1940 and worked all through the night bombarding Niers three samples with neutrons produced in the Columbia Unmiversity cyclotron. Dunning learned on Saturday that fissioning was produced only in the relatively rare U-235, and thus obtained evidence that U-235 was to be the key ingredient for making an atomic bomb from uranium. He and Columbia Prof. Eugene T. Booth then began looking into possible ways of separating U-235 from the 139 times more abundant U-238 isotope. Enrico Fermi, then working at Columbia made some rough calculations and figured that the amount of U-235 needed to make an atomic bomb ranged from as low as 44 pounds to as high as one or more tons! However, Fermis best guess, he said, was 287 pounds. No one had yet separated a fraction of an ounce of this material. Some physicists announced the task was so difficult that separating any amount was not likely. Prof. Harold Urey, who had earlier discovered deuterium, a heavy isotope of hydrogen that combines with oxygen to make "heavy" water, was accordingly considered the American authority on isotope separation and later became director of War Research for Columbia Universitys Atomic Bomb Project. In 1940 Urey declared he favored the gas centrifuge method being developed by Prof. Jesse Beams at the University of Virginia as the best way to separate uranium isotopes. Beams had already separated chlorine isotopes using his centrifuges. However, Dunning and Booth felt that Beams' mechanicallycomplex centrifuges of that day would not be suitable for the large-scale production required for the bomb project so they decided on gaseous diffusion as the best bet. Interestingly, British physicists were independently thinking through the very same questions as to how to go about separating the U-235 isotope, and they too came to the conclusion that the best potential route was gaseous diffusion. The United Kingdom focused all its World War II efforts on that process, with the end result being their Capenhurst diffusion plant. The concept of gaseous diffusion has been around for a long time, having been used to separate isotopes of neon, but separating the isotopes of a heavyFrom this first laboratory demonstration to a 44-acre plant in 3.5 years! The silver dollarsized barrier sample was held in the vertical disc- shaped holder near the top of the apparatus.

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element where the difference in weight was so small would be another matter. The basic idea was simple. The lighter molecules in a gas mixture move a little faster and so strike the walls of a container more often than the heavier molecules. If the walls have small enough holes in them, the lighter molecules will pass through more often. But those holes must be small enough to have true diffusive flow, in our case no larger than 2 millionths of an inch in diameter. And to get enough flow there must be many hundreds of millions of these tiny holes in a square centi meter, the size of your thumbnail. In this sheet of paper, imagine having some 10,000 holes side by side across its thickness! Instead of thinking of the porous membrane code named "barrier" - as a very fine screen or sieve, think of the size holes more like those in a clay flowerpot through which water slowly seeps; except ours must be a lot more porous to get useful flow rates.9

Dunning and Booths early work focused on alloys of brass (copper + zinc) and gold alloys from which they chemically dissolved out one of the constituent metals leaving a porous structure. In November 1941 they were able to demonstrate a small but real enrichment of UF6 gas in U-235. Wonderfully for us, their historic lab equipment was preserved. The actual equipment is on display in the Oak Ridge Room of the American Museum of Science and Energy (AMSE) in Oak Ridge.

The silver dollar size barrier sample was held in the disc near the top with UF6 (now missing) fed into the line to its left. The gray pump moved the gas to the copper tank in back.

With that demonstration, support for further work on diffusion grew quickly. Dean George Pegram of Columbias Graduate School recruited Prof. Francis G. Slack from Vanderbilt University who brought other researchers with him from Nashville. The Nashvillians made major contributions there and then later on when they transferred to Oak Ridge. The most difficult of the many problems they faced at Columbia proved to be that of making a barrier material with holes that are small enough, uniform enough, permeable enough, strong enough, without being brittle or fragile. Above all, the material had to resist chemical attack by the only usable uranium gas, uranium hexafluoride. This UF6 is a highly reactive compound that at room temperature looks like rock sugar candy, forming beautiful colorless crystals. 2 So the entire gaseous diffusion process must all be carried out hot - about 140F. The gas is decomposed instantly by moisture, including the humidity in air. It instantly turns UF6 into a bright yellow smoke of UO2F2 dust that will2

Dr. DeForest F. Smith of our Physics Dept. in the 1960's found that pure UF6 is very stable in carefully dried quartz, and made up some handsome ~1" dia. tubes about 8" long that we could show visitors. Holding it on one end in your hand would sublime the crystals to the other end, and over time they would grow beautifully. AEC Commissioner Clarence Larson, insisted in our making him one for his office in Washington, and our Pres. Roger Hibbs sweated bullets thinking of the result of it being broken accidentally. He finally got it back for us!

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plug up the barrier holes. Hence, all equipment must be dried very carefully and made vacuum tight before admitting the hot gas. What a challenge! Solving the barrier problem stymied scientists until almost the last minute - the summer of 1944. The details of how the multitudes of requirements were solved have never been revealed. The extraordinary achievements of hundreds of talented people who worked at Columbia University together with many from Kellex and Union Carbide have never been told, recognized, or appreciated by the public.Prof. John R. Dunning, early researcher and thenJohn Dunnings Columbia team, code named the Substitute Alloy Materials (SAM leader of the Labs), Columbia University teamgrew to nearly 200 people between 1942 and 1943. In highly secret

operations in Pupin Hall during that year, some progress had been made on the barrier problem, but no fully satisfactory barrier had been produced. The M. W. Kellogg engineering company devoted most of 1942 studying how to design a gaseous diffusion plant. Kellogg's theoretician Karl Cohen and engineer Manson Benedict made good progress through 1942 developing the theory and broad design principles. In early 1943, they were given the contract to design the K-25 Plant, and formed a new subsidiary, the Kellex Corporation to do it. In the summer of 1943 the Columbia program was re-organized and expanded. Prof. Harold Urey was put in overall charge and the work moved to two other buildings Schermerhorn and the Nash Building off campus. If you want to read a fascinating account of what it was like to work in that World War II lab while it was giving birth to this exciting new technology, read Don Traugers absorbing story in Chapter 5 of his memoir, Horse Power to Nuclear Power, available at AMSEs Discovery Shop. During the days of early construction of K-25 (1943-1944), efforts at Columbia intensified. Many new technical people were hired and trained to begin operating K-25 when enough of the plant was finished. Workers were so badly needed at Columbia that some of the enlisted technical men in Oak Ridge (the Special Engineer Detachment) were sent to help. Many who worked at Columbia in the SAM Labs ended up working at K-25 including: Don Trauger, John Shacter, Bill Lenihan, Paul Vanstrum, Dale Magnuson, Dr. Dixon Callihan, Warren W. Harris, Lorne Newman, Sylvan Cromer, Hank McKown, Bill Tewes, Dr. E. John Barber, I. C. (Sam) Flanders, Ted Shapiro, Elizabeth B. Libby Johnson, Dr. Sid Visner, Dr. Clifford Beck, Dr. Frank W. Hurd, A. A. Abbattiello, and John J. Schariter. Paul Vanstrum told me a about his arrival to work at SAM Labs in 1944 as a Union Carbide trainee. At lunch that first day when his SAM host learned that Van had graduated from the University of Minnesota, his host suggested that Van might know some people now working at SAM like Prof. Al Nier. Van replied, Oh yes, I was in his physics class at the time he did his first work on uranium-235. That "verboten" word brought the conversation to an immediate halt; the

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ensuing silence confirming Vans guesses about the subject of the secret research under way at Columbia University! - Paul Vanstrum

CHAPTER 3FORMIDABLE PROBLEMS IN PLANT DESIGN

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annevar Bush and James B. Conant were the top leaders of U.S. research and development efforts during World War II. Dr. Bush headed the Office of Scientific Research & Development (OSRD) and Dr. Conant, president of Harvard University, chaired the National Defense Research Committee (NDRC) and reported to Bush. To achieve the secrecy insisted upon by President Roosevelt, the uranium isotope separation project was buried in the NDRC and code-named the S-1 project during most of 1941 and 1942. Bush and Conant sought advice from special committees of the National Academy of Sciences (NAS). In November 1941, the month before the Japanese attacked U. S. Navy at Pearl Harbor, Bush and Conant received another NAS review of the practical prospects of obtaining enough U-235 for a bomb. That was the same month John Dunning and Eugene Booth first demonstrated some slight U-235 enrichment by gaseous diffusion at Columbia University using a rudimentary barrier. Vannevar Bush then summarized for President Roosevelt the National Academys November 1941 thinking for President Roosevelt: yes, uranium isotopes could be separated and made into an effective weapon, trial units of each of the candidate separation processes should be built and operated, and engineering studies should be started. Bush did not go into the reports technical details for FDR. But we know that the NAS report stated that, [1] the centrifuge method at Virginia was believed farther advanced than gaseous diffusion, and, [2] the Columbia research had uncovered many problems with the diffusion process. They were silent on the plutonium route to the atomic bomb because no one had yet demonstrated that one could achieve and then control a chain reaction. Pearl Harbor the next month, December 7, 1941, galvanized OSRD into action. A Planning Board was formed of outstanding chemical engineers who were charged with finding out if the centrifuge or diffusion methods could be operated on an industrial scale. In less than a month, by early 1942, the M. W. Kellogg Company, a top engineering firm with offices in Jersey City and New York City, was on the job receiving briefings by the Columbia team. Kellogg had wide experience developing processes from lab bench up to commercial plant scale. The dynamic man Kellogg put in charge of the diffusion

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effort was Percival C. Dobie Keith. He proved to be an inspiring leader and manager for the next five years. In his memoir Gen. Groves Percival C. (Dobie) Keith fumbled for the right words to describe this outstanding engineer-manager, finally settling on this awkward short sentence Keith was a brilliant scientific engineer. Keith and his Kellogg team went to work, soon finding out their job was not just to design a plant. Before they could even start they had to invent and develop some of the key equipment components like the pumps. They could appreciate the challenges posed by the goal of producing a satisfactory barrier. Dunnings team evaluated their progress in barrier technology not by trying to separate uranium isotopes, but by seeing how well a mixture of helium and carbon dioxide gases could be separated. The separation achieved with this pair of gases was large because of the difference in their weight, and the enrichment achieved was easy to measure chemically. Although those two gases are easy to handle, UF6 proved to be a different beast. The first big problem Kellogg faced was that of developing gas compressors, or pumpstwo for every stage, thousands for the plant. The pumps and their shaft seals could not be lubricated by any oils (hydrocarbons) because the process gas UF6 would react violently with them. Nor could those seals allow any leakage of moist air into or uranium gas out of the compressor for years! A postwar Kellex report states that company employees devoted 250,000 manhours just to research, development, and design for the pumps. Another major problem came from the fact that gas compression by the pump produces heat, so a gas cooler (like a car's radiator) is needed at every stage. Because any leaks of water (were it used as the coolant fluid) into the gas would be disastrous, an inert coolant had to be found, and it turned out ithat a whole new chemical family had to be invented the fluorocarbons. Also new types of valves that could be used with UF6 from tiny instrument line valves to large bypass pipes would be needed to control stage gas flows and to shut flow off. Then there was the whole knotty business of how to hook everything together. "Dobie" Keith brought in two brilliant persons who made enormous pioneering and breakthrough contributions: Karl Cohen, a theoretician and mathemetician, and Manson Benedict, the superb engineer Keith put in charge of the multi-stage process design. Benedict, who later taught for years at the Massachusetts Institute of Technology, deserves major credit, in my opinion, for the pioneering designs for how to stage and control this very complex process. In the postwar years, he consulted with Union Carbide Nuclear Division on improvement of the diffusion process and on the new centrifuge and other processes.

Manson Benedict, brilliant design engineer of the Kellex K-25 Plant team.

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In midyear 1942, Vannevar Bush transferred OSRD funding or the universities research work and assigned the program management function to the Army Corps of Engineers, thus creating the Manhattan Project., so named because the District Engineer in charge, Col. James C. Marshall, had his office in Manhattan. The site of the Oak Ridge Reservation had first been selected in May of 1942, but the Army studied and restudied the selected acreage until the first commander, Col. James Marshall, got a new boss, Gen. Leslie R. Groves in September, 1942. Whereas Col. Marshall had fiddled around all summer, Groves wasted no time at all, coming down to look the site over only two days after taking charge. He liked it, and issued the orders for the Army to buy up the 59,000 acres for the Manhattan Project. East Tennessee hasn't been the same since!

Col. James C. Marshall continued to serve as District Engineer reporting to Gen. Groves until August 1943 when he was replaced by Col. K. D. Nichols, who had been working with Col. Marshall since the Project was formed. In August 1943, Col. Nichols moved the Engineer District headquarters from Manhattan to Oak Ridge.Meanwhile, the more Dobie Keith and his engineers learned about the gaseous diffusion theory and requirements, the more optimistic and the more charged up they grew about its industrial possibilities.

CHAPTER 4KELLEX TACKLES K-25 PLANT DESIGN

T

he engineering studies conducted throughout 1942 by M. W. Kellogg Co. encouraged the Manhattan Projects Top Policy group to decide in December 1942 to forge ahead and build both the Y-12 amd the K-25 U235 separation plants. Kelloggs Dobie Keith, Benedict, Cohen and others had become more and more convinced that a diffusion plant could indeed perform the uranium enrichment job if a barrier material could be made that met the exacting criteria for its pore size, pore uniformity, permeability, ductility, corrosion resistance, and separation efficiency. That was a tall order, but so was the design of the balance of the plant. In their official history of the Atomic Energy Commission (AEC), The New World, Hewlett and Anderson summarize the frustration that the Kellex engineers felt when they watched the Columbia lab barrier researchers developing their production processes: The large number of variables in the barrier manufacturing processes might have appealed to the ingenuity of a

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temperamental chef, but to the process engineers the recipe was a nightmare. Kellogg during 1942 had made considerable progress in understanding cascade theoryhow to handle the problems of pumping enormous amounts of gas at the beginning of the cascade (the feed point) then ever decreasing gas flows up the cascade as the gas becomes increasingly richer in U-235 and below the feed point as it becomes depleted in U-235. Kellogg's early work sheets and layouts referred to the plant they were designing as K-25, a simple code in which the K stands for Kellogg and the 25 is a thinly disguised shorthand for the product U-235. By the time Groves army security experts became aware of the K-25 code name in early 1943, it had been in widespread use so long in Jersey City and New York drafting rooms that they decided changing it would have given away more than letting it ride. Incidentally, thats the only one of Oak Ridges four plant code names that has any rational basis. Near the close of 1942 Groves' top scientific committee headed by the esteemed chemical engineer Prof. Warren K. Lewis of MIT assessed the progress of the gas centrifuge (Virginia), gaseous diffusion (Columbia), and electromagnetic (California) methods. The committee decided to cancel any further development work on the centrifuge method which had already proceeded to the pilot plant stage. They studied the progress and were dismayed to learn over 10,000 highly complex centrifuges were required. The committee concluded that, ". . . of the three methods, Diffusion is believed to have the best overall chance of success, but the current (working) arrangement of Columbia and Kellogg will not do the job." What that meant was that precious time was being lost because Kellogg engineers and the Columbia scientists were working on different "wavelengths." Kellogg badly needed experimental facts to validate key design assumptions they were making, but they had no control over Columbias research priorities. But that situation and a lot more got fixed the very next month in what to us now is startlingly fast action thanks to Gen. Groves and Dobie Keith. Several examples: On Thursday, December 10, 1942, the hard-driving Gen. Groves made the decision (based on the committee's recommendation) to build the K-25 diffusion plant as well as the Y-12 calutron plant. On Saturday the 12 th, Groves met with "Dobie" Keith and asked him to talk M. W. Kellogg management into undertaking the tasks of completing the R&D, designing and procuring the special equipment, and then overseeing and directing the construction of K-25. On Monday the 14th, the managers of the Kellex Corporation, a brand new subsidiary of Kellogg organized specifically to do the K-25 job [with Keith as head], met with the top Army brass and signed the letter contract. How's that for action?

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Another example of how Groves made progresss - on Christmas Eve, 1942, Groves persuaded a very reluctant Tennessee Eastman Corporation to operate Y-12 without disclosing the purpose of the "vital war plant", just a couple weeks after convincing a very reluctant DuPont to run the Hanford plutonium production facility. Three weeks later, Jan. 18, 1943, the Army and Kellex management group all met with a team from Union Carbide, and Groves convinced Carbide management to serve as the operator of the K-25 plant. Dobie, it turned out, had recommended Carbide to Groves. Groves wasted no time lining up these three top U. S. chemical and chemical engineering contractors to carry out his mission to beat Germany to the bomb Union Carbide for K-25, Tennessee Eastman for Y-12, and E.I. DuPont for X-10 and Hanford. No wonder Robt. S. Norris calls Groves, "The Indispensible Man." In the winter and spring of 1943, Kellex swung into high gear, pulling together the Columbia and Carbide research and design teams and letting contracts with firms all over the country that produced fluorine and uranium hexafluoride (Harshaw Chemical of Cleveland, Ohio), that developed the compressors (AllisChalmers of Milwaukee, Wisconsin), that developed the very important pinholefree nickel plating techniques for all the piping (Chrysler of Detroit, Michigan), and new materials that would stand up to uranium hexafluoride (the fluorocarbons).

Comparison of the size of K-25 with that of Neyland Stadium at the University of Tennessee at Knoxville. From the Ehrenkrantz, Ekstut, and Kuhn Report, Capturing and Preserving the Historical Significance of K-25/K-27, January, 2004 In March 1943, Karl Cohens calculations revealed the required shape of each cascade, finally allowing Manson Benedicts Kellex group to lay out the equipment plot plan. They found that some 3,000 diffusing steps (called stages) were required, meaning that the building housing these cascades would have to be more than a mile long! Because of the limitations of the site, Benedicts engineers opted to design the building in the now familiar folded shape of the letter "U."

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Soon after, Dobie Keith and Gen. Groves met and decided they ought not rely solely on the Tennessee Valley Authoritys (TVAs) nearby Norris Dam for electricity for the vital new plant because they had been led by the Columbia researchers to believe a power failure would result in disastrous plugging of K25s barrier from which no recovery would be possible. So relying on a power plant more than 30 miles away involved too much risk of a power outage due either to severe weather or even to intentional sabotage of the overhead transmission lines. And the clinching argument was that K-25 required some variable frequency power. So the solution was to design and build the largest coal-fired power station in the world right at K-25. Dobie Keith said later he took some comfort in the notion that if the K-25 diffusion processs didnt work out, they could always sell the Powerhouse to TVA! Like K-25, the Powerhouse also set a size record it was the largest steamgenerating plant ever built in one step, having a generating capacity of 238,000 kilowatts, twice that of Norris Dam. As it turned out, to my knowledge, the only overt act of attempted sabotage in Oak Ridge during World War II occurred during construction of the K-25 Powerhouse. A nail or spike was found driven through one of the cables intended to carry power over to the K-25 "U." The incident was carefully investigated, but detectives never could determine whether an enemy agent, sympathizer, or disgruntled worker was responsible for the crime. Groves, who relates the story in his book, Now It Can Be Told, thought a disgruntled worker most likely damaged the cable. Ground was broken for this huge steam plant on June 2, 1943 and nine months later the first steam was generated beating even Groves's schedule. The powerhouse was a complete success meeting all design requirements. Its cost was $38 million.

CHAPTER 5CONSTRUCTION OF THE MAMMOTH PLANT

I

n the first months of construction, the unpaved roads to and from the K-25 site became almost impassable as a result of rains, heavy trucks and earth movers. Early traffic from Kingston and the west had to cross the Clinch River on the hand-powered Gallaher Ferry. Steel for the K-25 Powerhouse had to be delivered by truck until the spur railroad was built and connected to the Southern Railroad line at Blair, Tennessee. Usually plans for building projects are complete before construction begins, but this was wartime and Gen. Groves realized if they waited until they knew all the answers, the K-25 diffusion plant could not be ready in time to make any difference in the war. So the contractor, J. A. Jones was ordered to start the site preparation and construction of the building shell, steel framing, and other infrastructure for the enormous "U- shaped building. Ground was broken for the

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K-25 "U" building on groundbreaking for Y-12.

September

27,

1943,

seven

months

after

the

Throughout 1943 and 1944 Kellex engineers in Jersey City and New York City continued to work frantically solving the dozens of problems in developing equipment for the process to be installed inside the K-25 U building. In April 1944, Dr. George Felbeck of Carbide and Carbon Chemicals Company, the future operator of K-25, was given the job of supervising all of the crucial barrier development work, everyones biggest worry. What a risk K-25 was! Building this enormously large and costly building without even knowing that the key element for its success could even be made! Without a good barrier, the building would be worthless! In his memoirs, Groves wrote that if K-25 hadnt been successful, he saw himself spending the rest of his life in Congressional hearings. By any standard, construction of the mammoth K-25 "U" was a monumental undertaking. Kellex made 12,000 engineering drawings for laying out 3,000 diffusion stages in a continuous process using a U-shaped arrangement of 54 building units. From one end to the other

The K-25 "U" from the south or "open" end. The feed building in the middle is feeding the gas into the east wing (above right) and it is being enriched all the way around the"U" until finally coming out near this end of the west wing.

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around to the other end, a worker would ride a bicycle along those inner windows for a mile. The U building for the most part was 400 feet wide, and it covered 44 acres and had four stories. The first Vault floor, which opens to ground level outside the "U," contained the electrical switchgear, ventilation fans, and transformers. The second Cell floor, which opens to ground level on the inside of the "U," contained all the main diffusion process equipment. The third Pipe Gallery floor held all the interconnecting piping. The fourth Operating floor, where the operators worked, contained all the instrument and control panels, as well as cell bypass valve handles. The three thousand stages required six thousand pumps (gas compressors) and three thousand gas coolers (heat exchangers), as well as a half-million special valves, and hundreds of miles of nickel-plated gas piping hooking it all together. In addition, a wealth of instrumentation was required to measure temperatures, pressures and any in-leakage of air and to transmit the data up to the operating floor. Four million feet of copper tubing and three million miles of copper wire were threaded throughout the "U" building. Inside the "U" courtyard near the far end in the photo above, was the largest air-drying plant ever built. And the system for removing heat from the process used redwood cooling towers (northwest of the "U") that re-circulated enough water daily to supply a city of five million people. The construction contractors really shook their heads in disbelief when the Army engineeers explained the requirements for cleanliness control and vacuum tightness. The first requirement called for thousands of components and process piping to undergo degreasing, cleaning, drying and sealing to keep the interiors free of organic substances, such as even a thumb print! And Vacuum tight required exhaustive leak testing and repairs until the whole system was as leaktight as the walls of a Thermos bottle. The managing contractor, J. A. Jones Co., found its most difficult challenge was the coordination of the work of 16 subcontractors working all over the huge worksite (imagine, without cell phones!) In May 1945 the J. A. Jones construction workforce peaked at 24,785, with the largest number (5,472) being plumbers/steamfitters and the next highest being electricians. Oak Ridge had no place to house thousands of construction workers, so J. A. Jones had to build a town for them that evolved into a small city.

CHAPTER 6OAK RIDGES LOST CITY

W

ould you believe that during World War II the Clinton Engineer Works reservation hosted not only Oak Ridge but also a second city with a population roughly three times that of the nearby city of Clinton? When J. A. Jones Co. started hiring its construction crews to build K-25, they soon

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learned that no residences were available in Oak Ridge to house additional workers. The citys hutments, trailers, and flattops were jammed with construction workers expanding both the Y-12 Plant and the city itself. So J. A. Jones built a "construction camp" of 450 hutments, 16 feet by 16 feet, on the south side of Gallaher Ferry Road [now State Route 58] across from the plant entrance reaching eastward from the present pond. That space for maybe 2500 men was just a start. When the first hutments were built there in the fall of 1943, life was primitive. J. A. Jones had to truck in from Oak Ridge [10 miles away] all the water needed each day by hutment residents! The hutments were little better than tents. Each had cots for four to six men, a central stove for heating, no glass windows, just wooden shutters that could be propped open in summer or closed in winter. A central bathhouse for every couple dozen or so hutments provided showers and lavatories. As more and more workers arrived the "camp" grew like "topsy." The name of the "camp" on the J. A. Jones and Kellex drawings was simply "J.A. Jones Construction Camp." But the residents soon sarcastically dubbed their town "Happy Valley," and that's what it was called then and ever since. Within a year a small "city" had sprung up with more and more amenities. At the peak the Happy Valley boasted 900 trailers for families, four big dormitories housing more than 1,200 men, 8 big barracks housing women and men in separate wings, 100 "Victory Homes" (a patriotic euphemism in those wartime days that meant "temporary"), as well as a sea of hutments segregated by race. The community was served by four big Army cafeterias, three recreation halls, a movie theater, bowling alley, bank, barber shop, drug store, dispensary, and a service station. Across the main Oak Ridge-Gallaher highway was a Town Hall that included a post office, a laundry and an ice house, as well as the preexisting Wheat High School and the George Jones Memorial Baptist Church. The latter is the sole building standing of this once so busy community.

Bear Creek Valley (Y-12) Geo.Jones Baptist Church Wheat School Happy Valley School 900 Trailers 100 Victory Cottages Dormitories

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Mess Hall #2 Coney Island Rec Hall Barracks

Hutments The eastern half of Happy Valley looking east toward Oak Ridge. Probably 1946 Present Highway 58 is on the left.

The aerial below shows the western end of Happy Valley in 1945 with K-25 off in the distance. The camera is facing northwest, so the photo above shows the town stretching off to the right of the image below. The Oak Ridge highway is at the bottom of this photo, curving across the photo. Both this photo and the one on the following page are from the Oak Ridge Public Library Westcott Collection.

K 1401, 10 acre Conditioning Bldg.

Maintenance Shop

Town Hall/Post Office

Mess Hall

Coney Hall

Island

Rec

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The present Highway 58 is the heavy black line; Oak Ridge is 10 miles to the right, I -40, 5 miles to the left. The now demolished four-wing K-25 Administration Building is at upper left; Wheat High School is at upper right. Map from the Oak Ridge Room Map Collection, Oak Ridge Public Library. When the Army took over the Wheat Community, the fine big brick Wheat High school was pressed into service by Carbide, K-25's operating contractor, as a personnel office and training building for supervisors. By 1945 the population of Happy Valley had grown to 12,000some references in books say 15, 000. Life was hectic, but people enjoyed being with others "in the same fix," all sharing wartime shortages, waiting in lines, and all the "ersatz" substitutes. Some well-known Oak Ridgers still love telling their Happy Valley stories. Helen Jernigan, in later years a leading citizen and public servant of Oak Ridge, lived in one of Happy Valleys barracks as a young single woman and had a summer job in the amusement arcade called Coney Island. You can read her fascinating story of what living in Happy Valley was like in These Are Our Voices, a book published by the Childrens Museum of Oak Ridge. Tom Mullinix, a K-25 engineer, lived for a while in one of Happy Valleys infamous hutments until deciding anything would be bettereven a daily commute from Knoxville. Colleen and Jo Rowan (later Black and Iacovino) lived with their mother and father in one of the trailers and still love to tell about those Spartan days. The war was never far from anyones mind because of its many impacts on our daily existence.

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When the war ended, construction was still under way on the new and separate diffusion plant named K-27. It was to be the first of a series of odd-numbered, postwar expansions of our nations uranium enrichment capacity. K-27 was designed by Kellex using the same drawings as for part of K-25, but it is much smaller than K-25, having 9 building sub-units (K-25 had 54) and 540 stages (K25 had 3,000). So Happy Valley continued to exist through 1946 for K-27 and then for site construction cleanup. After 1946, Happy Valleys population declined rapidly, and by the end of the decade, Happy Valley was virtually all gone. The site will be well marked as part of our K-25 history preservation efforts. Another construction camp, quite a bit smaller than Happy Valley was built in 1944 by Ford Bacon & Davis (FB&D), the construction and operating contractor for K-1401, the conditioning building. A vital part of the K-25 plant, this 1000-foot-long, 400-foot-wide building received by rail all 3,000 diffusers packed with precious barrier tubes made by Chrysler in Detroit, as well as all the compressors, motors and other stage equipment. K-1401 FB&D personnel assembled all the components and gave them a final chemical treatment with fluorine to ensure they were clean, dry, and ready for Carbide to install in the "U" building where they would be exposed to the very corrosive uranium hexafluoride gas. The FB&D construction town grew to 2,000 residents. It was The author with a Happy Valley fire located northeast of K-25, on the hill behind the quarry. hydrant. This FB&D town was not far from where the K-25 barrier plant was Ray Smith Photo by D. later built. These communities so vital to Oak Ridges early development served their purpose and then were green-fielded. They have vanished with very few traces. In March 2006 Oak Ridge Mayor David Bradshaw and local historian D. Ray Smith escorted the Atlantic Films documentary production team on a tour through the Happy Valley site searching for remnants of that lost city. The crew finally found a fire hydrant standing alone in the empty woods, handsomely aged with the patina of 60 summers and winters. Further searching revealed some foundations of communal bath houses used by hutment residents. But the land where thousands of construction workers once lived full lives with their families while building the huge K-25 plant now rests in a deep sylvan peace.

CHAPTER 7OAK RIDGES LOST PLANT

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n the last chapter we told the story of Oak Ridges lost sister city, Happy Valley. Would you believe that not far from Happy Valley was a $16 million plant ($1.8 billion in 2007 dollars) that has also vanished? In World War II its code name was the S-50 Thermal Diffusion plant, the facility built to enrich uranium gas in the U-235 isotope using a still different method than that used in either the huge Y-12 or K-25 Plants. The thermal diffusion process was the brainchild of Dr. Philip H. Abelson, a brilliant maverick whose World War II research efforts were supported not by the Manhattan Project but by the U. S. Navy! Unlike the other scientific fathers of the Manhattan Project processes, for example Dunning, Lawrence, Fermi, Abelson was the brains and driver behind not only the research phase but also behind the engineering, construction, and operations phases. A former student of Prof. E. O. Lawrence at the University of California at Berkeley, Abelson was an early advocate of thermal liquid diffusion for producing U-235. Like gaseous diffusion, the basic idea behind thermal diffusion sounds simple enough. Hot uranium hexafluoride liquid under pressure is introduced into a very small circular space between a nickel pipe and a copper pipe that is just a little bit larger. The nickel pipe is heated on the inside by very hot (~500 degrees) high pressure steam and the copper pipe is cooled on the outside by water. If the spacing is small and uniform, then a little bit more of the light U235 isotope collects along the hot wall and more of the heavy U-238 isotope collects on the cold wall, and then because of convection, the U-235 drifts to the top of a tall column while U-238 sinks to the bottom. No problem until you try to do it! In 1940 Dr. Abelson started doing his first experiments on the process and soon learned that the U. S. Navy was interested in supporting his research. The Navys interest stemmed not from their desire to make a bomb, but rather from the desire to build a nuclear reactor small enough to power a submarine that could stay submerged much longer than a diesel fueled submarine. Just like with gaseous diffusion and all the other uranium enrichment processes, making thermal diffusion work on a large scale proved extremely challenging. Abelson recognized early on that the spacing between the hot and cold pipes was critical to the success of the process. The spacing had to be very small and the pipes had to be almost perfectly round or the separation of the isotopes would be degraded. Abelson, in a paper delivered to the "International Symposium on Isotope Separation" in Amsterdam in 1957 emphasized the critical importance and the great difficulty of achieving and maintaining this very small annular spacing. He stated that for uranium hexafluoride (UF6), the hotcold spacing needed to be about 0.025 centimeters. This is 0.01 inches, about the thickness of 3 to 4 sheets of this paper! Interestingly, the Germans had looked at thermal diffusion. And the Japanese Navy, after "studying all known enrichment processes", decided to focus all their experimental efforts on thermal diffusion. However, the spacings they chose to use between the hot and cold walls were much too large, so no uranium

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enriched in U-235 was ever produced. The March 9/10, 1945 U. S. firebombing of Tokyo destroyed the Japanese thermal diffusion experimental facility. Abelson progressed from using 6 foot high columns in 1941 to 36 foot high columns for his pilot plant in Maryland that was finished in November 1942, just about the time Gen. Groves and his technical advisers started narrowing down the processes for the enrichment plants to be built at Oak Ridge. They shook their heads in dismay when they heard Abelson's description of a possible thermal diffusion plant requiring thousands of tall, precisely built, carefully nested pipes filled with liquid uranium hexafluoride under high pressures with very low separation factors and very long equilibrium times. Groves team

S-50 is the long black building -- 525 long, 82 wide, and 75 high. The K-25 Powerhouse (Steam Plant) is located at its right, and the U.S. Navy auxiliary steam plant is at left end of the S-50 Plant in this 1945 Ed Westcott photo. The Clinch River is in foreground, K-25 upper right. Courtesy Oak that thermal diffusion could not quickly agreedRidge Public Library DOE Photo Collection. be one of the two production

processes on which they would stake the success of the Manhattan Project. Even after Groves ruled out spending any additional money or time on thermal diffusion, the Navy decided to continue supporting Abelsons project. And his work progressed to even longer columns. By 1944, Abelson was ready to start building a 1,000-column pilot plant with each column 45 feet tall at the Philadelphia Navy Yard in Pennsylvania. That same spring Oppenheimer at Los Alamos was briefed on Abelsons progress. Oppenheimer had a new idea, and suggested to Groves that since the K-25 Powerhouse would be finished months before its steam would be needed to generate electricity for K-25, why not use that high-pressure steam to heat an Abelson thermal diffusion plant with columns just like those being built for his pilot plant in Philadelphia? Even though the enrichment level reached would be

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low, like maybe even only 1%, the productivity of the Y-12 Plant would be significantly improved if Y-12 could start with feed even slightly enriched in U235 instead of the 0.7% that it was when dug out of the ground. Groves recognized the value of this new idea of having the three plants (Y-12, K25, and S-50) all working together. One wonders if maybe he didnt choke a little about turning to the Navy for help because thermal diffusion was its baby that hed rejected two years before and refused to fund. But Groves was not one to pass up any way to speed up his Project. So he asked Col. Kenneth Nichols, his Number 2 man, to put together an interplant production control team to do what we now call Operations Research or Operation Analysis, and find the optimal way to operate all the plants (Y-12, K-25, and the new S-50) as one! The result was a masterful stroke that provided Los Alamos with the required highly enriched uranium for "Little Boy" almost a month before it would have happened had not all three processes worked together. 3 H. K. Ferguson of Cleveland, Ohio was chosen to design and build the plant, and because of the unusual steam supply situation, the Army asked them to have it built in a nearly impossible 75 days. The first columns was ready for steam in 69 days! Then Ferguson was asked to operate the plant since they knew it and could do it faster than anyone else. They created a subsidiary named The Fercleve Co. (Ferguson + Cleveland) to operate the S-50 plant. Many U.S. Navy personnel came to Oak Ridge to help operate the facility. In April 1945 the S-50 workforce peaked at 1600 after being joined by 126 U.S. Army technically trained soldiers, members of Oak Ridges Special Engineer Detachment (SED). S-50 was started up in September 1944. However, in early 1945 because K-25 had then started and required electricity generated by the K-25 Powerhouse, the U. S. Navy brought in boilers from destroyers that were fueled by diesel oil. These boilers were installed in another small powerhouse just for S-50. To fuel these boilers 13 large diesel oil storage tanks were installed, each with its own earthen dike in case of spillage, all stretched out along the east bank of the Clinch River. See the aerial photograph on page 27.

3

Groves retired from the Army in 1948 and went to work for Remington Rand. He was called upon often to speak about the Project, and sometimes made the point that WWII was costing the country $250 M/day and if the bombs shortened the war by 8 days it paid for the Masnhattan Project. Robt.S. Norris, Racing for the Bomb, Steerforth Press, 2002. 30


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A few of S-50s 2,142 thermal diffusion columns, each 48 feet tall. Operators worked on and near the catwalk at the top of the columns, where one told me, the noise of steam leaks, the heat and the height made the plant pretty unpleasant for workers.

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Two photos of the S-50 thermal diffusion plant taken from the roof of the K-25 Powerhouse next door. S-50 is the long black building in the center. The top photo was taken in the fall of 1944 when the plant was first finished and could rely on the K-25 Powerhouse for its superheated steam. The lower photo was taken in 1945 after the U.S. Navy built a separate steam plant for S-50 because the Powerhouse was needed to supply electricity to K-25 for uranium enrichment by gaseous diffusion. That power plant is shown at left between its twin stacks. It burned diesel oil stored in the 13 tanks seen in the background. The stacks

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were demolished in 2006 by BJC, and a monument will be built using some of those bricks. WWII photos by Ed Westcott, courtesy of Steve Goodpasture, CDM. The 48-feet-tall thermal diffusion columns were remarkable. The specifications on the clearances were so tight that only two companies responded out of dozens that the Army asked for proposals. The 1-inch diameter in-most nickel pipe contained the superheated steam (545F @ 100 psi) and was nested securely in the center of a slightly larger copper pipe, leaving the very precisely fixed ~ 0.01-inch annular spacing through which flowed the liquid uranium hexafluoride under high pressure. These two pipes were in turn nested inside a 4-inch galvanized iron pipe carrying the cooling water to cool the outside of the copper pipe. The temperature difference between the hot nickel and cold copper pipe was the key to the separation of the uranium isotopes. Dr. Herbert Hoffman, the only Oak Ridger still around who I know worked there, told me that the superheated steam leaking out of some joints made a fearsome racket. It was not a pleasant place to work. S-50 was shut down in September 1945, a month after the war ended, and was dismantled shortly thereafter. During the early 1950s K-25 plant personnel decontaminated, cut up and scrapped all the thermal diffusion columns. The S-50 thermal diffusion plant operated only one year, but the slightly enriched feed (0.9% U-235) that it provided shortened the time required for the Y-12 Plant to produce enough U-235 for the first atomic bomb by 7 to 9 days. 4 In view of the tremendous daily cost of the war in lives and dollars, Col. Nichols in his memoir judged that shortening World War II by one week made S-50 well worth its cost. The only remnants of S-50 and the K-25 Powerhouse that could be seen in 2005 were the two smokestacks of the Navys powerhouse, but they were declared to be in poor condition and knocked down by Bechtel Jacobs. The historic site of SW-50, Oak Ridges Lost Plant, will be provided with an historic marker as part of our historic K-25 preservation project.

CHAPTER 8EQUIPPING THE K-25 "U" PLANT

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ometime every Oak Ridger or visitor to Oak Ridge should go to "Wheat Station" at the Heritage Center and ride the Secret City Scenic Excursion Train. The train runs through Heritage Center along the K-25 "U" building then out about six miles to Blair Junction. Hard to believe today as you ride, but that rail bed saw tens of thousands of rail cars bring in all the materials required to build the K-25 plant in 1944 and 1945 and all went back out empty! In Chapter 5, I explained how complez and demanding the construction of K-25 plant was. However, equipping the gaseous diffusion plant was an even more daunting task. At every turn the essentials needed for the process had to beNichols, The Road to Trinity, page 150. Confirmed by Hewlett and Anderson, The New World. 33

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invented or developed. The available compressors, valves, and instruments available from American industry could not be used because the process gas uranium hexafluoridereacts with or corrodes almost all the common metals and reacts almost explosively with organic materials like oils and greases. And it reacts instantly with water, even the moisture in air, producing a yellow dust or solid product (UO2F2) while at the same time giving off nasty hydrogen fluoride gas. But the greatest challenge of all was the development of the diffusion membrane, then code named and still called "barrier". In late fall of 1943 when construction of the big K-25 powerhouse was well under way and more than 10,000 construction workers had started erecting the steel framing of K-25, the plant up in Illinois built to make the barrier had still not produced a single acceptable tube! The contractor there was the Houdaille-Hershey Corp., then the countrys largest user of finished nickel for plating automobile bumpers. The company built a $5 million plant during the summer of 1943 in Decatur, Illinois to produce barrier tubes by the thousands using what then was thought to be the best process - the very complex Norris-Adler process developed at the Columbia University "SAM" Labs. That's the process the Kellex engineers described as a nightmare (see Chapter 4). Sheldon Jacobs, long-time Oak Ridger, worked at the Decatur plant and when it closed then came to K-25 as did others who worked there. On Christmas Day 1943, the chief executive officer of Houdaille-Hershey telephoned Gen. Groves to inform him that his company was giving up, they had tried for many months but just could not produce barrier of the required product quality using that Norris-Adler process. He expected Groves to go ballistic, but Groves was almost relieved. A raucous debate had been raging for six months between the Columbia laboratory enthusiasts for Norris-Adler and the group favoring a competing, newer process developed by Kellexs Clarence Johnson. Since June 1943, Dobie Keith of Kellex and George Felbeck of Union Carbide had both been strongly arguing that the Johnson process was superior. Nobel Laureate Harold Urey, still an influential voice, backed his Columbia teams Norris-Adler process as did the British gaseous diffusion team who came over again to exchange ideas about that time. (Churchill had talked Roosevelt into holding joint technical exchanges on the Project.) Dobie Keith of Kellex hotly criticized the Norris-Adler product as nothing but a lace curtain, emphasizing the point to visitors to his office by smashing a piece of the fragile stuff across the edge of his desk! Following Houdaille-Hersheys Christmas 1943 declaration, Groves convened all the people involved in developing barrier processes in a meeting at Decatur, Illinois in mid-January 1944. There Groves stated his decision to abandon the once-favored Norris-Adler process and bet the bank on this new approach. The technical details of the new process are still under wraps in 2007. Interestingly, the new Kellex barrier produced at the Decatur plant was not an immediate success. By April 1944, four months later, the new process still had not produced barrier that delivered even five percent (5%) of the quality needed for the K-25 Plant! But with a concerted effort of all involved, the quality was

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improved to 38% in May. Then by the fall of 1944, to the great relief of every one, acceptable barrier tubes were being made and shipped in coffin-like boxes from Decatur, Ill. to Detroit, Michigan. To Detroit? Yes, because another of Gen. Groves traditional strategies was to enlist the help of people he knew could deliver under pressure. This time he called upon K. T. Keller, an old acquaintance at Chrysler Corporation in Detroit. At that time Chrysler was swamped with war work making tanks for the Army, but Groves didnt hesitate to ask Keller to do even more for the war effortto take on [1] the job of providing 3,000 diffusers (sometimes today still called by their wartime code-names converters, tanks or even filters), and then [2] to figure out how to stuff them full of the precious barrier tubes. Groves explained to Keller that the only metal known to contain the uranium hexafluoride gas without corroding was nickel, and that the country did not have near enough of that metal to make the 3,000 diffuser shells and all the piping. The obvious answer was to use nickel-plated steel, but Columbia University scientists had been searching the country in vain for a company that could electroplate nickel without introducing occasional pinholes that ruined the metals resistance to the highly corrosive uranium hexafluoride. Keller accepted the challenges. His plating experts at Chrysler astounded the Columbia chemists by soon developing a pinhole-free plating process that used the diffusers and piping themselves as the plating tanks. Then Chrysler perfected new welding techniques needed for nickel-plated steel. And the car manufacturer turned its Lynch Road facility in Detroit into a secret plant for nickel plating and for installing the thousands of barrier tubes now being secretly shipped there in coffin-like boxes from Houdaille-Hershey in Illinois. According to a Chrysler post-war memoir, simply titled Secret, the Lynch Road facility environment was as clean as a health clinic.

Chrysler's Lynch Road (Detroit) nickel plating facility for pipe and the inside of the diffusers. Photograph from Wesley W. Stout, Secret , Chrysler Corp., 1947, page 65. (approved for public release).

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Chrysler personnel then mounted the precious cargo of nickel-plated diffusers all packedwith barrier tubes onto special vibration-free mounts on railway flatcars. These transported the secret equipment south to Blair, Tennessee, and then through the woods to the huge K-1401 building at K-25. There a separate contractor who had built that 10 acre building, Ford, Bacon, & Davis, "conditioned each piece of the diffusion equipment with fluorine gas so it would withstand the corrosive UF6 process gas. Finally, the crucial components were turned over to Carbide personnel, who trucked them over to the massive"U" building where they were installed through the Withdrawal Alleys. In the photograph below, one of the diffusersin this case the steel tank about four feet in diameter with its three stiffening ringsis shown installed inside the cell housing.

A gaseous diffusion stage. The cylindrical tank at left is a diffuser that contains barrier tubes. The stage and floor are enclosed by sheet-steel housing that was heated to vaporize the UF6. Part of the housing has been removed for this photo to show the diffuser. In the housing wall that remains is the circular centrifugal pump (a.k.a. compressornote all the bolts) with its electrical drive motor at right. Procuring the circular centrifugal pumps for compressing the UF6 gas proved almost as challenging, because the required custom designs were unlike anything available. Groves and Keith convinced Allis-Chalmers management to take on this job, even though Allis-Chalmers was overloaded with the work of fabricating large silver-wound electromagnets for the Y-12 Plant.

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Keith brought in some outside experts to help Allis-Chalmers develop the detailed designs required for pumping and compressing the uranium hexafluoride gas. But the major stumbling block for Kellex for over a year was the problem of providing a shaft seal. Some way had to be found to keep air from leaking into the pump along the rotating shaft from the motor driving the pump. In industry, the common way to seal shafts is to provide a packing gland around the shaft lubricated by grease or heavy oil. But UF6 would burn up these lubricants. Kellex researchers proposed two radically new solutions. One idea failed but the other succeeded; the details still under wraps. Allis-Chalmers built a $4 million factory in Milwaukee, Wisconsin, and eventually shipped 7,000 compressors of five different sizes south to Blair, Tennessee in rail cars. Final assembly of their pumps was made in K-1401 and then they also were trucked over and installed in the K-25 "U" building. The K-1401 building also served as the plant's Maintenance Shops, where everything went back to get fixed if trouble developed. It was one of the most vital buildings on the area.

CHAPTER 9START-UP OF THE MAMMOTH PLANT

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t the close of the frenzied 1944 construction year, the J. A. Jones construction crew began to see light at the end of the tunnel. And the Kellex engineers breathed a little easier as they began to witness hordes of women and men workers successfully leak testing and and then sealing up leaks. They celebrated the news that the pipes, pumps, and pressure monitoring instrument lines and valves were being certified as leak tight, and they were delighted by Chrysler's shipments of diffusers packed full of acceptable barrier.

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This is the back side of one of the hundreds of big (about 6' tall) operating instrument panels that monitored the pressures at various points in the K-25 cascade. This is just one example of the complex copper tubing instrument lines and valves, all of which had to be made leak tight. Also notice the fine craftsmanship - all hand cut, bent, and soldered. Now Union Carbide was in the hot seat. They were the managing contractor responsible for operating this awesome complex.

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Looking up the outside of the West Wing from near its south end. Those frequent, windowed protrusions from the main building house staircases leading up to the Operating (top) floor.

All through the year 1944 Carbide was rounding up potential K-25 supervisors and managers from their other plants whom they could transfer to Oak Ridge as well as busily hiring new college graduates. Carbide also was able to use hundreds of the active duty, technically trained soldiers of the Oak Ridge Special Engineer Detachment (SED). Many of the new K-25 employees were sent up north to Columbia University to learn gaseous diffusion technology and become trained as plant supervisors or specialists in the future laboratories to be built at the K-25 site. Using the same wartime practice as done at Y-12, the operating contractor did not wait until the buildings were all finished by the construction contractors, but as portions of the building and installation of equipment got fairly far along, the operating contractor moved right in and worked along side them starting the equipment checkout while the constructions crews finished up their work. This saved a lot of time in testing equipment, moving in, preparing for start-up, and doing the initial shakedowns. At K-25, J. A. Jones and Carbide employees near the end of 1944 began working in joint teams and turned over the first 60 of the eventual 3,000 gaseous diffusion stages at the end of 1944. Working together, the teams tested pumps, instruments, and most importantly, the leak tightness of everything. Leak tightness was absolutely critical because39

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the process had to operate below atmospheric pressure (as a partial vacuum) so any leakage would not be uranium gas leaking out, rather wet air leaking in.

Shown above is about twenty feet of the mile long third floor of the huge K-25 "U" building. This is the Piping Gallery that serves to interconnect the enormous system together. Each inch of all these pipies had to be leak tested and made vacuum tight. Prof. A. O. C. Nier of the University of Minnesota was the inventor of the "Helium Leak Detector" - the key instrument that helped worker make the whole system vacuum-tight. Nier based its design on the principle of his earlier invention, the powerful analytical mass spectrometer. The leak detector however is specifically tuned to detect helium, a light gas. And because it doesn't react with anything (an inert gas), it is safe for people to use it's the same gas used to inflate party balloons and the Goodyear blimp. Leak testing at K-25 involved pumping all the air out of the piece of equipment being tested then "spraying" a stream of helium gas over the outside. The tiniest leak of helium through a weld or joint would be detected quickly and the exact place then marked for the repair crew to fix before testing again. Leak testing K-25s miles of pipes, thousands of pi

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