Making of the Atomic Bomb
Plutonium production at Hanford depended as much on chemical separation as it did on chain-reacting piles. The chemistry was Glenn Seaborg’s, spectacularly scaled up a billionfold directly from his team’s earlier ultramicrochemical work. The plutonium in the slugs irradiated in the Hanford piles emerged mixed to the extent of only about 250 parts per million with uranium and highly radioactive fission products. Carrier chemistry—the fractional crystallization of Marie Curie and Otto Hahn—was therefore required to help the scant plutonium along. The man-made metal is extremely poisonous if ingested but only mildly radioactive. To make it safe to handle it also needed to be purified to less than 1 part in 10 million of fission products. And because the pile slugs developed such a burden of radioactivity, all but the final chemical processing had to be carried out by remote control behind thick shielding.2245
Seaborg’s team developed two separation processes to take advantage of the different chemistries of plutonium’s several different valence states. One process used bismuth phosphate as a carrier; the other used lanthanum fluoride. Bismuth phosphate, scaled up directly from Met Lab experiments, served the primary purpose of uranium and fission-product decontamination. Lanthanum fluoride, applied at pilot scale at Oak Ridge, then concentrated the plutonium from the large volume of solution in which it was suspended.
Hanford was the largest plant Du Pont had ever constructed and operated; not least among its facilities were the chemical separation buildings. “Originally eight separation plants were considered necessary,” writes Groves, “then six, then four. Finally, with the benefit of the operating experience and information obtained from the Clinton semi-works, we decided to build only three, of which two would operate and one would serve as a reserve.” For safety the plants went up behind Gable Mountain ten miles southwest of the riverside piles. Each building was 800 feet long, 65 feet wide and 80 feet tall, poured-concrete structures so massive the workers called them Queen Marys; the British ocean liner of that name was only a fifth again as long.2246 The Queen Marys were essentially large concrete boxes, says Groves, containment buildings “in which there were individual cells containing the various parts involved in the process equipment. To provide protection from the intense radioactivity, the cells were surrounded by concrete walls seven feet thick and were covered by six feet of concrete.”
Each Queen Mary contained forty cells, and each cell’s lid, which could be removed by an overhead crane that rolled the length of the building’s long canyon, weighed 35 tons. Irradiated slugs ejected from a production pile would be stored in pools of water 16.5 feet deep to remain until the most intense and therefore short-lived of their fission-product radioactivities decayed away, the water glowing blue around them with Cerenkov radiation, a sort of charged-particle sonic boom. The slugs would then move in shielded casks on special railroad cars to one of the Queen Marys, where they would first be dissolved in hot nitric acid. A standard equipment group occupied two cells: a centrifuge, a catch tank, a precipitator and a solution tank, all made of specially fabricated corrosion-resistant stainless steel. The liquid solution that the slugs had become would move through these units by steam-jet syphoning, a low-maintenance substitute for pumps. There were three necessary steps to the separation process: solution, precipitation and centrifugal removal of the precipitate. These would repeat from equipment group to equipment group down the canyon of the separation building. The end products would be radioactive wastes, stored on site in underground tanks, and small quantities of highly purified plutonium nitrate.
Once the Queen Marys were contaminated with radioactivity no repair crews could enter them. Equipment operators had to be able to maintain them entirely by remote control. The operators trained at Du Pont in Delaware, at Oak Ridge and on mockups at Hanford, but the engineer in charge, Raymond Genereaux, sought more authoritative qualification. And found it: he required his operators, one hundred of whom arrived at Hanford in October 1944, to install the process equipment into the first completed separation building by remote control, pretending the canyon was already radioactive. They did, awkwardly at first but with increasing confidence as practice improved their remote-manipulation skills.
“When the Queen Marys began to function,” Leona Marshall remembers, “dissolving the irradiated slugs in concentrated nitric acid, great plumes of brown fumes blossomed above the concrete canyons, climbed thousands of feet into the air, and drifted sideways as they cooled, blown by winds aloft.”2247 B-pile slugs traveled by rail into the 221-T separation plant beginning on December 26, 1944. “The yields in the first plant runs . . . ranged between 60 and 70 per cent,” Seaborg notes proudly, and “reached 90 per cent early in February 1945.”2248 Lieutenant Colonel Franklin T. Matthias, Groves’ representative at Hanford, personally carried the first small batch of plutonium nitrate by train from Portland to Los Angeles, where he turned it over to a Los Alamos security courier. Thereafter shipments—small subcritical batches in metal containers in wooden boxes—traveled in convoy by Army ambulance via Boise, Salt Lake City, Grand Junction and Pueblo to Los Alamos.
Bertrand Goldschmidt, the French chemist who worked with Glenn Seaborg, puts the Manhattan Engineer District at the height of its wartime development in perspective with a startling comparison. It was, he writes in a memoir, “the astonishing American creation in three years, at a cost of two billion dollars, of a formidable array of factories and laboratories—as large as the entire automobile industry of the United States at that date.”2249
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One of the mysteries of the Second World War was the lack of an early and dedicated American intelligence effort to discover the extent of German progress toward atomic bomb development. If, as the record repeatedly emphasizes, the United States was seriously worried that Germany might reverse the course of the war with such a surprise secret weapon, why did its intelligence organizations, or the Manhattan Project, not mount a major effort of espionage?
Vannevar Bush had raised the question of espionage with Franklin Roosevelt at their crucial meeting on October 9, 1941, when Bush apprised the President of the MAUD Report, but the OSRD director got no satisfactory answer, probably because the United States was not yet a belligerent. Groves in his memoirs passes the buck to the existing intelligence agencies—Army G-2, the Office of Naval Intelligence and the Office of Strategic Services, the forerunner of the CIA—and attributes the inadequacy of their information to “the unfortunate relationships that had grown up among [them].”2250 Why he failed to confront the issue himself until late 1943, when George Marshall asked him directly to do so, he chooses not to say. One reason was certainly security, a Groves obsession; in order to know what to look for, intelligence agents would have to be briefed on at least isotope-separation technologies and nuclear-fission research, which would mean that any agent captured or turned might well give American secrets away. When Groves finally did take responsibility for intelligence gathering he picked scientific personnel who had not worked within the Manhattan Project and authorized paramilitary operations to advance only into areas already occupied. That at least is how he intended his intelligence unit to operate; in practice it frequently claimed its prizes in the no-man’s-land between fighting fronts, by hook or by crook.
The unit Groves authorized in late 1943 somehow acquired the name Alsos, Greek for “grove” and thus obscurely revealing; the brigadier thought to have it renamed, “but I decided that to change it . . . would only draw attention to it.”2251 To head the Alsos mission he chose Lieutenant Colonel Boris T. Pash, a former high school teacher turned Army G-2 security officer, FBI trained, who had made himself notorious in domestic intelligence circles for his flamboyant investigation of Communist activities among members of the staff of Ernest Lawrence’s Berkeley laboratory. Pash, trim and Slavic, with rimless glasses and light, thin hair, spoke Russian fluently and was a great hunter of Communists. His background helps explain why: his Russian emigré father was the Metropolitan—senior bishop—of the Eastern Or
thodox Church in North America. It was Pash who had interrogated Robert Oppenheimer about his Communist affiliations while a clandestine recording device in the next room preserved the physicist’s damaging evasions on blank sound motion picture film; he concluded without hard evidence that Oppenheimer was a Communist Party member gone underground and possibly a spy. Whatever Groves thought of Pash’s Red-baiting, he chose him to head Alsos because he delivered the goods: “his thorough competence and great drive had made a lasting impression on me.”2252
Pash set up a base in London in 1944 as the Allied armies pushed through France after the Normandy invasion. He then crossed the Channel with a squad of Alsos enlisted men and wheeled toward Paris by jeep. “The ALSOS advance party joined the 102nd U.S. Cavalry Group on Highway 188 at Orsay,” a contemporary military intelligence report notes. The American force stopped outside Paris—Charles de Gaulle had persuaded Franklin Roosevelt to allow the Free French to enter the city first—but Pash decided to improvise: “Colonel Pash and party then proceeded to cut across-country to Highway 20 and joined second elements of a French armored division.2253 The ALSOS Mission then entered the City of Paris 0855 hrs., 25 August 1944. The party proceeded to within the city in the rear of the first five French vehicles to enter, being the first American unit to enter Paris.” The five French vehicles were tanks. In his unarmored jeep Pash drew repeated sniper fire. He dodged among the back streets of Paris and by the end of the day had achieved his goal, the Radium Institute on the Rue Pierre Curie. There he settled in for the evening to drink celebratory champagne with Frédéric Joliot.
Joliot knew less about German uranium research than anyone had expected. Pash moved his base to liberated Paris and began following up promising leads. One of the most significant pointed to Strasbourg, the old city on the Rhine in Alsace-Lorraine, which Allied forces began occupying in mid-November. Pash found a German physics laboratory installed there in a building on the grounds of Strasbourg Hospital. His scientific counterpart on the Alsos team was Samuel A. Goudsmit, a Dutch theoretical physicist and Paul Ehrenfest protégé who had studied criminology and had previously worked at the MIT Radiation Laboratory. Goudsmit followed Pash to Strasbourg, began laboriously examining documents and hit the jackpot. He recalls the experience in a postwar memoir:
It is true that no precise information was given in these documents, but there was far more than enough to get a view of the whole German uranium project. We studied the papers by candlelight for two days and nights until our eyes began to hurt. . . . The conclusions were unmistakable. The evidence at hand proved definitely that Germany had no atom bomb and was not likely to have one in any reasonable form.2254
But paper evidence was not good enough for Groves; as far as he was concerned, he could close the books on the German program only when he had accounted for all the Union Minière uranium ore the Germans had confiscated when they invaded Belgium in 1940, some 1,200 tons in all, the only source of untraced bomb material available to them during the war with the mines at Joachimsthal under surveillance and the Belgian Congo cut off.
Pash had already liberated part of that supply, some 31 tons, from a French arsenal in Toulouse where it had been diverted and secretly stored. Moving into Germany with the Allied armies after they crossed the Rhine late in March he acquired a larger force of men, two armored cars mounted with .50-caliber machine guns and four machine-gun-mounted jeeps and began tracking the German atomic scientists themselves. “Washington wanted absolute proof,” Pash remembers, “that no atomic activity of which it did not know was being carried on by the Nazis. It also wanted to be sure that no prominent German scientist would evade capture or fall into the hands of the Soviet Union.”2255 Alsos moved through Heidelberg and picked up Walther Bothe, whose laboratory contained Germany’s only functioning cyclotron. Documents there pointed to Stadtilm, near Weimar, as the location of Kurt Diebner’s laboratory. The small town proved to have become the central office of the German atomic research program as well, and although Werner Heisenberg and his group from the Kaiser Wilhelm Institutes had moved to southern Germany to escape Allied bombing and the advancing Russian and Allied armies, there was a small amount of uranium oxide at Stadtilm to reward Pash’s search.
Pash missed the ore rescue. Groves’ liaison man with the British had been watching a factory at Stassfurt, near Magdeburg in northern Germany, since late 1944, when documents captured in Brussels indicated it might house the balance of the Belgium ore. By early April 1945 the Red Army had advanced too close to that prize to leave it uninspected any longer; Groves arranged to assemble a mixed British and American strike force led by Lieutenant Colonel John Lansdale, Jr., the security officer who had cleared Paul Tibbets, to move in. The team met with the Twelfth Army Group’s G-2 in Gottingen to seek approval for the Stassfurt mission; Lansdale describes the confrontation in a report:
We outlined to him our proposal and advised him that if we found the material we were after we proposed to remove it and that it would be necessary that we act with the utmost secrecy and greatest dispatch inasmuch as a meeting between the Russian armies and Allied armies apparently would soon take place and the area in which the material appeared to be was a part of the proposed Russian zone of occupation. [The G-2] was very perturbed at our proposal and foresaw all kinds of difficulties with the Russians and political repercussions at home. Said he must see the Commanding General.2256
That was calm, no-nonsense Omar Bradley:
He went alone in to see General Bradley, who at that time was in conference with [the] Ninth Army Commander within whose area Stassfurt then was. Both of them gave unqualified approval to our project, General Bradley being reported to have remarked “to hell with the Russians.”
On April 17, led by an infantry-division intelligence officer familiar with the area, Lansdale and his team struck for Stassfurt:
The plant was a mess both from our bombings and from looting by the French workmen. After going through mountains of paper we located the lager or inventory of papers which disclosed the presence of the material we sought at the plant. . . . This ore was fortunately stored above ground. It was in barrels in open sided sheds and had obviously been there a long time, many of the barrels being broken open. Approximately 1100 tons of ore were stored there. This was in various forms, mostly the concentrates from Belgium and about eight tons of uranium oxide.
Lansdale instructed his group to take inventory and went off to Ninth Army headquarters. That organization assigned him two truck companies. He moved on to the nearest railhead within the permanent American zone of occupation but found the commanding officer there too busy evacuating some ten thousand Allied prisoners of war to be able to offer more help than half a dozen men for guard duty. Lansdale improvised, located empty airport hangars nearby where the ore could be stored awaiting shipment out of Germany and arranged to have them cleared of booby traps. Then he returned to Stassfurt:
Many of the barrels in which the material was packed were broken open and the majority of those not broken open were in such a weakened condition that they could not stand transportation.2257 [A British and an American officer] and I took a jeep and scouting around the country found in one small town a paper bag factory which had a large supply of very heavy bags. We later sent a truck and obtained 10,000 of these. We also discovered in a mill a quantity of wire and the necessary implements for closing the bags. By the evening of 19th April we had a large crew busily engaged in repacking the material and that night the movement of the material to [the railhead] started.
Boris Pash in the meantime continued to chase down the German atomic scientists. Alsos documents placed Werner Heisenberg, Otto Hahn, Carl von Weizsäcker, Max von Laue and the others in their organization in the Black Forest region of southwestern Germany in the resort town of Haigerloch.2258 By late April the German front had broken and the French were moving ahead. Pash and his forces, which now included a battalion of combat engineers, got word in the middle of the night and raced
around Stuttgart in their jeeps and trucks and armored cars to beat the French to Haigerloch. They drew German fire along the way and returned it. In the meantime Lansdale in London reassembled his British-American team and flew over to follow Pash in. The story is properly Pash’s:2259
Haigerloch is a small, picturesque town straddling the Eyach River. As we approached it, pillowcases, sheets, towels and other white articles attached to flagpoles, broomsticks and window shutters flew the message of surrender.
. . . While our engineer friends were busy consolidating the first Alsosdirected seizure of an enemy town, [Pash’s men] led teams in a rapid operation to locate Nazi research facilities. They soon found an ingenious set-up that gave almost complete protection from aerial observation and bombardment—a church atop a cliff.
Hurrying to the scene, I saw a box-like concrete entrance to a cave in the side of an 80-foot cliff towering above the lower level of the town. The heavy steel door was padlocked. A paper stuck on the door indicated the manager’s identity.
. . . When the manager was brought to me, he tried to convince me that he was only an accountant. When he hesitated at my command to unlock the door, I said: “Beatson, shoot the lock off. If he gets in the way, shoot him.”
The manager opened the door.
. . . In the main chamber was a concrete pit about ten feet in diameter. Within the pit hung a heavy metal shield covering the top of a thick metal cylinder. The latter contained a pot-shaped vessel, also of heavy metal, about four feet below the floor level. Atop the vessel was a metal frame. . . . [A] German prisoner . . . confirmed the fact that we had captured the Nazi uranium “machine” as the Germans called it—actually an atomic pile.
Pash left Goudsmit and his several colleagues behind at Haigerloch on April 23 and rushed to nearby Hechingen. There he found the German scientists, all except Otto Hahn, whom he picked up in Tailfingen two days later, and Werner Heisenberg, whom he located with his family at a lake cottage in Bavaria.