pipe interiors, a difficult new process accomplished by filling the pipes themselves with plating solution and rotating them as the plating current did its work.
The plant that would hold thousands of diffusion tanks, the largest of them of 1,000 gallon capacity, would be necessarily monumental: four stories high, almost half a mile long in the shape of a U, a fifth of a mile wide, 42.6 acres under roof, some 2 million square feet, more than twice the total ground area of Y-12's Alpha and Beta buildings. K-25, as the gaseous-diffusion complex was designated, needed more than a narrow ridge valley. The building and operating contractors, Kellex and Union Carbide, found a relatively flat site along the Clinch River at the southwestern end of the reservation; the first surveying, for the coal-fired power plant needed to run the factory, began on May 31, 1943.
Rather than designing and setting thousands of different columns for footings the construction contractors leveled and compacted the entire K-25 foundation area, plowing, drying and moving in the process nearly 100,-000 cubic yards of red clay. That took months; the first concrete — 200,000 cubic yards — was not poured until October 21. By then the continuing failure to develop an adequate barrier material had led Groves to decide to lop off the unfinished plant's upper stages and limit its enrichment potential to less than 50 percent U235 — it would have been capable of taking natural uranium all the way to pure U235 with its full complement of diffusers — and to use this enriched material to feed the Beta calutrons at Y-12.
Kellex succeeded in devising a promising new barrier material in the autumn of 1943 that combined the best features of the Norris-Adler barrier and the compressed nickel-powder barrier. The problem then was what to do about the Houdaille-Hershey plant under construction in Decatur, which was designed to produce Norris-Adler. Should it be stripped and reequipped to manufacture the new barrier at the price of some delay in starting up K-25? Or should the several barrier-development teams make a final concerted effort to improve Norris-Adler to production quality? Over these significant questions Groves and Harold Urey violently clashed.
Kellex wanted to strip the Houdaille-Hershey plant and convert it, preferring delay to the risk of failure. Urey thought abandoning the Norris-Adler barrier would mean forgoing the production of U235 by gaseous diffusion in time to shorten the war. In which case he saw no reason to continue building K-25; its high priority, he argued, would even hinder the war effort by displacing more immediately useful production.
Groves decided to submit the dispute to an unusual review committee: the experts who had worked on gaseous diffusion in England. With the renewal of interchange between the British and American atomic bomb programs that autumn the British had arranged to send a delegation to work in America. Led by Wallace Akers of ICI, the group included Franz Simon and Rudolf Peierls. It met with both sides — Kellex and Columbia — on December 22 and then settled in to review American progress.
The participants reconvened early in January 1944. The new barrier, the British concluded, would probably be superior eventually to the Norris-Adler, but they thought the months of research on the Norris-Adler must count decisively in its favor if time was of the essence. The new barrier had been manufactured so far only by hand in small batches. Yet K-25 would require acres of it to fill the planned 2,892 stages of the diffusion plant's cascade.
Then Kellex set a trap: it proposed to produce the new barrier by hand by piecework — thousands of workers each duplicating the simple laboratory process Kellex had initially devised — and claimed that by doing so it could match or beat the Norris-Adler production schedule. When the British had recovered from their surprise at the novelty of the proposal they signaled their preference for the new barrier by agreeing that if production was possible it ought to be pursued. That agreement sprang the trap; with the British implicitly committed, the American engineers revealed that they could only manufacture the new barrier by stripping the Houdaille-Her-shey plant and forgoing Norris-Adler production entirely.
Groves in any case had already decided, the day before the January meeting, to switch over to the new barrier; the British review then simply ratified his decision. By changing barriers rather than abandoning gaseous diffusion he confirmed what many Manhattan Project scientists had not yet realized: that the commitment of the United States to nuclear weapons development had enlarged from the seemingly urgent but narrow goal of beating the Germans to the bomb. Building a gaseous-diffusion plant that would interfere with conventional war production, would eventually cost half a billion dollars but would almost certainly not contribute significantly to shortening the war meant that nuclear weapons were thenceforth to be counted a permanent addition to the U.S. arsenal. Urey saw the point and withdrew; “from that time forward,” write his colleague biographers, “his energies were directed to the control of atomic energy, not its applications.”
Twelve days after Enrico Fermi proved the chain reaction in Chicago on December 2, 1942, Groves had assembled a list of criteria for a plutonium production area and definitely and finally ruled out Tennessee. “The Clinton site… was not far from Knoxville,” he comments, “and while I felt that the possibility of serious danger was small, we could not be absolutely sure; no one knew what might happen, if anything, when a chain reaction was attempted in a large reactor. If because of some unknown and unanticipated factor a reactor were to explode and throw great quantities of highly radioactive materials into the atmosphere when the wind was blowing toward Knoxville, the loss of life and the damage to health in the area might be catastrophic.” Such an accident might “wipe out all semblance of security in the project,” Groves could imagine, and it might render the electromagnetic and gaseous-diffusion plants “inoperable.” Better to site plutonium production somewhere far away.
The production piles needed plentiful electricity and water for blowing and cooling the helium that was planned to cool them. For safety they needed space. Those criteria suggested the great river systems of the Far West, particularly the Columbia River basin. Groves sent out an officer who would administer the plutonium reservation along with the civilian engineer who would supervise construction for Du Pont. Besides picking the site he wanted the two men to get used to working together. They did, agreeing on a promising location in south-central Washington State, and arrived back in Groves' office on New Year's Eve to report. The general received a real estate appraisal on January 21, 1943. By then he had already personally walked the ground.
Eastward of the Cascade Range, twenty air miles east of the city of Yakima, the blue, cold, fast-running Columbia River bends east, then northeast, abruptly ninety degrees southeast and finally due south through a flat, arid scrubland on its last excursion toward the continental interior before it makes its great bend below Pasco to course directly westward two hundred fifty miles to the sea. Even that far inland the river is wide and deep and veined in season with salmon, but the sandy plain surrounding wins little of the river's water and the barrier of the Cascades denies it more than six inches a year of rain.
The site Groves' representatives discovered, and Groves acquired at the end of January at a cost of about $5.1 million, was contained within the eastward excursion of the Columbia: some 500,000 acres, about 780 square miles, devoted primarily to sheep grazing but varied with a few irrigated orchards and vineyards and a farm or two thriving in wartime on irrigated crops of peppermint. Temperatures ranged from a maximum of 114° in the long, dry summers to rare — 27° winter lows. Roads were sparse on the roughly circular thirty-mile tract. A Union Pacific railroad line crossed one corner; a double electric power line of 230 kilovolts traversed the northwest sector on its way from Grand Coulee Dam to Bonneville Dam. Gable Mountain, an isolated basalt outcropping that rose five hundred feet above the sedimentary plain a few miles southwest of the ninety-degree river bend, divided the riverside land at the bend from the interior. Midway down the tract where a ferry crossed the Columbia, a half- abandoned riverside village, population about 100, supplied a base of buildings and gave the Hanford Engineer Works its name.
Groves could hardly build Hanford until he knew more about the plant that would go there. It was clear that he would need enormous quantities of concrete to shield the production piles and chemical processing buildings; his Hanford engineer searched out accessible beds of gravel and aggregate to quarry. An accident might release radioactivity into the air; that called for thorough meteorological work. The river water needed study; so did the river's valuable salmon, to see how they would take to mild doses of transient radioactivity from pile discharge flow. Roads had to be paved, power sources tapped, hutments and barracks built for tens of thousands of construction workers.
What had come up once again for discussion early in 1943 was how the plutonium production piles — the Du Pont engineers were beginning to call them
