Manhattan Project Director’s Files Illuminate Early History of Atomic Bomb

Appointed by General Groves to direct a weapons laboratory in mid-October 1942, Oppenheimer began an active effort to recruit top scientists. He wrote to Harvard University President James Conant about his interest in acquiring Robert Bacher, then with M.I.T.’s Radiation Laboratory; Franz Kurie at the U.S. Navy’s Radio and Sound Laboratory; and Raymond G. Herb, University of Wisconsin, who was also working at M.I.T.’s Radiation Laboratory. Apparently, neither Herb nor Kurie was interested or recruitable, but Oppenheimer went to great lengths during the months that followed to persuade Bacher to join and was eventually successful. This carbon copy was part of the package that Oppenheimer sent to Groves on 9 November (see Document 2).[5]

The first page of J. Robert Oppenheimer’s letter to General Groves can be found on the Department of Energy’s OpenNet, but the signed original in the Groves office files may be the only available version with the “personnel list” attached. In the letter, Oppenheimer demonstrated that, by early November 1942, he had been busily recruiting top physicists to staff the new laboratory for “our program” even before there was an agreed site. The “personnel list” that he sent to Groves included a core group of experimental and theoretical physicists “now working for us” and a wish list of others whom he saw as essential. Oppenheimer included a separate page with an “explanatory note” for the lists, with various initials noting who had approved them (either Oppenheimer, Edwin McMillan or Ernest Lawrence). The list also included coding indicating who was “essential” (or just “good”), whether they were “aliens,” and whether they were married or not, among other characteristics. As Oppenheimer noted, the list did not include the “very large” number of graduate and undergraduate students “who are working with these men.”

The list of those “men now working for us” included a few who never worked at Los Alamos, but it included many who played important roles there, including Edwin M. McMillan, John H. Manley, Joseph L. McKibben, Charles P. Baker, Emilio Segre, Robert Serber, Edward Teller and Hans Bethe. The list of “Men Whose Prompt Release We Desire” included some who later joined the project, such as Robert Bacher, Richard Feynman, Enrico Fermi, Robert F. Christy, Herbert L. Anderson and Luis Alvarez. Others proved unobtainable, such as Raymond Herb, Franz Kurie, Percy Bridgman and James L. Lawson. Oppenheimer wrote in gendered terms about those who would staff the new lab; he may have used the word “man,” as was typical then, to describe people in general, but he listed only males for these positions. Yet in those days, men were the ones with standing in the field and the requisite education and skills. A few female scientists would work at Los Alamos.

In his letter to Groves, Oppenheimer mentioned several documents that he had enclosed, one concerning a “major equipment problem,” the other about a “young man who is now in the army and whom we would like to have assigned to us.” Neither show up in the file, but they may be in the classified papers in this collection or in some other group of records altogether.

At the close of the letter, Oppenheimer wrote that he hoped to see Groves in New Mexico. Six days later, on 16 November 1942, when Oppenheimer was traveling in the state with Edwin McMillan and Major John H. Dudley to select a site for the laboratory, Groves joined the group. After visiting Jemez, which they ruled out, they inspected the site of a prep school in Los Alamos, which Groves readily accepted for what became known as “site Y.”[6]

Constructing the HEW plutonium production complex required thousands of skilled and semi-skilled workers (the peak number of construction workers neared 45,000), housing arrangements, and amenities to encourage them to stay on the job (See Document 14). It also required managers to oversee construction along with technicians and scientists to operate the reactors, reprocessing plants and related facilities. They also needed suitable housing, especially if they brought their families. To make that possible, the Manhattan Project paid for new housing in Richland, WA, paying for everything, including lightbulbs and furniture. This was not an easy process because Groves and Du Pont did not agree completely on housing requirements or their costs, among other issues concerning the development of Richland. While Du Pont wanted to support the housing needs of managers and scientists, Groves and Matthias wanted to keep costs down.

In what amounted to a directive to E.B. Yancey, the General Manager of Du Pont’s explosives department, HEW “area engineer” Colonel Franklin Matthias noted that the company wanted to construct the remaining unbuilt houses in three- or four-bedroom units. He cited the company’s “reluctance to build one or two bedroom units for … for remainder of program.” Matthias instructed Du Pont to “fit housing to actual estimated family sizes.” According to Matthias, “peace time experience as to needs for space does not apply now when it is of the utmost importance to conserve manpower and materials.”

In his response, Yancey made the point, among others, that the remainder of the unbuilt houses should have mainly three bedrooms, which he saw as “minimum requirements.”

Backing up Matthias, Groves sent a telegram to Yancey saying that he saw “no reason for not complying” with the request, although he was willing to discuss the matter further.

When the Manhattan Project designated land in Washington state as the site for the Hanford Engineer Works, it began proceedings to acquire large swathes of land, over 400,000 acres—some 600 square miles—so that the secret plants could be built and operated safely and far from the view of unwanted observers. In implementing federal policy to acquire the land and compensate private landholders, Assistant U.S. Attorney General Norman M. Littell played an important role. With political ambitions in Washington state, Littell was concerned about the slow procedures for compensation and wrote that “residents being dispossessed from this big area of our State ... will suffer very considerable hardships from delay in payment.” However, did not take secrecy all that seriously, as he made clear in this comment to Senator Wallgren [D-WA]: “The War Department considers this project to be ‘secret’ and asks for no publicity on it, although I do not quite see how so great an event in the State of Washington, inevitably attended by considerable comment and the conducting of public proceedings in the courts, can in any way be maintained as ‘secret.’”

Littell’s concerns about compensation and his skepticism about secrecy presaged run-ins that he had with Groves and that contributed to a White House decision to fire Littell in 1944.[7] In any event, Littell greatly underestimated the determination of War Department officials to maintain the secrecy of Hanford operations. For example, HEW project director Franklin Matthias successfully appealed to the patriotism of local newspaper editors by asking them to stay clear of stories of government land acquisition, dispossession of farmers, and subsequent construction activities at Hanford. The HEW’s existence remained secret until after the atomic bombings of Japan.[8]

Prepared by some unknown compiler for the use of General Groves and other top officials, this report provided a full picture of the land in Washington state that the War Department acquired for HEW operations. The compendium provided detail on land ownership, population, agriculture, irrigation districts, transportation, schools, and land acquisition procedures. At the end of the compilation is a set of photographs. If the maps mentioned in the report are in the Groves files, the Archive’s FOIA request may ultimately open them up.

The compendium gave an overview of the history, noting the 1942 laws that authorized the Secretary of War to acquire by “purchase, donation, transfer, or condemnation” real property required for military purposes, and citing a 9 February Secretary of War directive to acquire the land. According to the report, “Area A,” consisting of over 193,000 acres, was “situated in the center of the project.” Thus, a few weeks later, on 23 February, the War Department took the first step by filing a petition of condemnation with the U.S. District Court for “immediate possession” and occupation of Area A. The estimated cost to acquire that area was $3.2 million, while the estimated cost for all of the land—areas A, B, C, D, and E—was over $5.1 million. As it turned out, by December 1946, litigation brought by claimants would bring land acquisition costs to over $5 million. Not mentioned in the report was the Native American tribal group, the Wanapum, which had fished in the Columbia River for centuries.[9]

Included in the photos—numbers 11 through 14—is Gable Mountain, the area south of which would become the site of the plutonium separation plant. Other photos depict orchards, some destroyed or abandoned, irrigation ditches, a dam, the village of White Bluffs, and power lines.

Getting enough workers to build the reactors, reprocessing facilities and other sites at Hanford was a huge task, and General Groves was doubtful that Du Pont executives were handling it with the right attitude. A letter from Walter O. Simon, a Du Pont manager at HEW, irritated Groves because of its “super-cautious” tone and a statement about a schedule “set back” for the construction of Areas 100 (reactor) and 200 (reprocessing plant). Groves refused to accept any delays, and his response produced a somewhat aggrieved letter from Ackart, who blamed “stringent” government controls over labor but assured the General that the job will be done “at the earliest date possible.” The last point is what Groves wanted to hear because, in his view, “it is mandatory on all of us to handle the job in such a way that the important areas will be completed at the earlies possible dates regardless of any previously suggested schedules or any difficulties which may be thrown in our respective ways.”

Prepared by top Groves’ aide Colonel Kenneth Nichols months before any of the reactors or the reprocessing plant were operating, the first memorandum provided estimates for the labor force needed to build “three operating units”—presumably two reactors and one reprocessing plant—and requisite supplies of plutonium at various time intervals. The quickest completion time for the three units, in two-month intervals—would require 48,000 workers. (As it turned out, the peak workforce was around 43,000). The basis for the labor force estimates was a production schedule for 12- or 18-kilogram units of plutonium based on the time intervals. For example, one 12-kilogram “unit” would be produced 13 months after the reactors (pile) started operating, assuming a two-month interval for the completion of reprocessing plants.

Nichols recommended trying to “complete all three units at two-month intervals.” While there was little difference in estimated plutonium output between the 2-4 and the 2-6 schedules compared to 2-2, he favored the “faster schedule” to “provide for contingencies.” By the point where HEW could produce 12 or 18 kilograms of plutonium-239, it would have been close to operating at full capacity because it would already have been producing small amounts.

The minimum critical mass of a sphere of plutonium-239 is around 10 kilograms, so that may have made a capacity to produce 12 kilograms a desired goal. When Nichols prepared his report, weapons designers at Los Alamos were assuming that they could use the plutonium to produce a usable gun-assembly weapon. That proved technically impossible, and Los Alamos found an alternative design based on implosion technology.[10]

Plutonium production later moved beyond Nichols’ estimate. By September 1944, the “B” reactor had reached criticality, and in late December 1944, spent fuel arrived at the “T” reprocessing plant. Soon, Hanford was producing plutonium, making its first delivery to Los Alamos on 4 February 1945. Production grew fairly rapidly, especially after Groves and HEW leaders found ways to accelerate it to provide enough plutonium for a test device and a weapon.. [11] According to a recent estimate, by August 1945, eight months after the reprocessing plant was operating, Hanford had already produced 17.5 kilograms of plutonium, more than enough for the Trinity Test and the bomb that exploded over Nagasaki.

The second memorandum concerned recommendations for the possible suspension of heavy water (P-9) production as a cost-saving measure. That such a significant heavy water production capacity had been built speaks to the huge resources that the Manhattan Project had its disposal but also to the ability of its managers to put on the back burner investments whose importance had lessened. This was implicit in the decisions that Groves made in October 1943 to give low priority to work on a heavy water reactor for producing plutonium. (See Document 17)

Two of the plants recommended for closure, Alabama and Wabash River, had higher production costs compared to the Morgantown plant. The report included contractual data for the Consolidated Mining and Smelting plant at Trail in British Columbia. Operated by the Manhattan Project, the plant’s entire output would be designated for the heavy water research reactor at Argonne, Illinois.[12]

Building a hitherto unknown, complex, and hazardous technology made Du Pont executives “apprehensive” about safety, which had been important to their corporate culture.[13] They wanted to be sure that, if the world’s first nuclear production reactor failed, that nearby workers would be safe. Granville Read sent Groves two sets of maps “indicating the number of people associated with our construction organization and the distance they will be working from the operating units.” According to Read, when the ‘B’ [reactor] unit began operations there would be “approximately 50,000 people within a 12-mile radius of the operating unit.” Read wanted Groves’ assurances that, “under conditions in which the performance of the operating unit did not proceed in a controllable manner and that all of the safety control mechanisms fail to function, the distances given on our maps are adequate protection for the health and safety of the employees involved.” If Groves was confident that the maps were correct, Read asked him to sign one of the sets of maps and return them.

In his reply, Groves wrote that, after consulting scientists, it was their and his opinion that “the distances on the maps ensure proper protection for the health and safety of the employees involved.” Accordingly, he signed the maps, copies of which remain classified in the Groves collection.

Responding to a request from Colonel Nichols, Stowers sent estimates of construction costs at the HEW, including costs for the reactors and reprocessing facilities. The estimates include the costs for each category of installation: $100 for reactors, $200 for reprocessing plants, $300 for fuel fabrication, and $700 for administrative and other offices. One important problem that managers would have to grapple with, if far from systematically, was storing nuclear waste, including the poisonous chemical byproducts from the reprocessing plant. Some of the items in this document may relate to waste management, such as items 282 (reservoir & pump house), 611 (waste settling basin) and 612 (open storage ditch), although their purposes are far from clear. In any event, by 1944, HEW had begun the infamous “tank farm” for storing waste from the T plant.[14]

The numbers used in the chart are in 1944 dollars, but it is possible to take into account price level changes since then to get an approximation of the costs in 2024 dollars. This can be done by using Department of Defense deflators. Unfortunately, the earliest military construction deflator provided by Defense is for 1945, but that is reasonably close. In the chart, the estimated cost for the three reactors (“100 area”) was over $101 million dollars. Using the deflators, the estimate in 2024 dollars is in the range of $2 billion. According to the chart, the cost for the reprocessing plants (“SP Process Area”) was some $47 million dollars. Using the deflators, the adjusted cost in 2024 dollars is in the range of $960 million. For the fuel fabrication facility (300), the estimated cost was over $2.1 million. Adjusted for 2024 dollars using Defense Department deflators, the cost for that facility is over $42 million. [15]

By March 1944, Groves was greatly concerned about the slow pace of the settlements with property holders in Washington state who had gone to court to seek better compensation for their land. Over 1200 cases remained unsettled, procedures were slow, and Groves was aggrieved by jury decisions to award values “greatly in excess of the Government appraisals.” To protect the HEW’s “essential secrecy,” Groves wanted the cases closed, payments made expeditiously, and juries kept away from the properties at issue. Specifically, he wanted the Justice Department to make arrangements with the Courts to “eliminate the practice of the jury viewing the land” before they made a decision on compensation. Groves did not have his way on this point until March 1945.[16]

Groves sent this memo to General Brehon Somervell, chief of U.S. Army logistics, whose organization was an important source of secret funding for the Manhattan Project and whose role gave him a voice in overall policy, including land settlements.[17]

To accelerate the availability of housing for managers, scientists and others in the HEW’s more permanent staff, Matthias arranged to have 2,300 prefabricated houses built in Oregon and shipped to Richland.[18] To see how the “general living conditions” were compared to other housing, Groves asked Matthias to arrange a survey. The results showed that there were few complaints, but an important difference was that “the prefabricated houses show a considerable higher temperature both inside and outside.” Nevertheless, the prefabricated houses were “more comfortable than the average houses in this area excluding the new houses built.”

Read sent Groves a chart with a schedule for the completion of major facilities at Hanford. On the most critical goals, both the B reactor (100 category) and the T reprocessing plant (200 category) were already or nearly completed. The T plant would start operations at the close of September. More reactors and reprocessing plants were to be completed and begin operations during the months after September 1944. Other categories scheduled for completion were offices for maintenance, operations, and administration (700 category) and housing (1100). Also included in the chart was a “force reduction curve” indicating a steady decrease in the HEW labor force in the following months.

The labor force curve is broken down into two parts: with most of the work done on a “fixed fee” basis: the $1 fixed fee and reimbursables. Some work was done on a “lump sum” basis, apparently a specific payment for agreed work, including costs only.

For the towns of Hanford and Richland, the HEW leased concessions to private operators so that they could supply food and other necessities to workers, managers, scientists, and others. In Richland, HEW also made arrangements for a hotel, cafeterias, a coffee shop and a news stand. For concessions, including the hotel, the U.S. government shared in the gross receipts on a percentage basis, while the cafeterias and coffee shop paid monthly rent. The coffee shop operated at a loss but was a necessity for hotel guests and others.

With the Office of Price Administration (OPA) regulating and monitoring prices, Kirkpatrick found that “prices charged in stores at Richland have been in line with OPA ceiling regulations” and had “been competitive with those charged in the general territory.” An exception was the drug store, whose prices were a “little high,” while Safeway prices were “the minimum that can be charged in the area.”

Kirkpatrick recommended reviews of each concession contract with the amount of profit to be determined and earnings carefully watched, but also to ensure that the concessions stayed in place until the HEW’s work ended. Groves approved the recommendations instructing Kirkpatrick to carry them out “insofar as practical.”

Poor bookkeeping and excessive profits to a contractor operating games of skill led to an investigation of the Hanford Employees’ Association that HEW managers had established in December 1943. With labor turnover high during the construction phase, managers decided that the creation of an employees’ association was a “must” to improve morale. According to the reports, workers were “leaving their jobs simply because there was no welfare or athletic program to provide entertainment in their leisure hours.” While Du Pont had set up a recreation building with pool tables, bowling alleys and games of skill, among other features, for HEW managers, that was not enough.[19]

The Hanford Employees Association published a newspaper and sponsored nationally known dance bands, baseball games, baseball leagues, football games, concerts and lectures. Apparently, some in HEW management saw bringing in dance bands and professional sports teams as “unwise,” probably for security reasons, but nevertheless necessary for morale purposes.

With construction winding down, Matthias wanted to scale back the Employees’ Association but not eliminate it yet. Du Pont had been involved in managing the association but did not “favor” it, probably because it wanted employees to have responsibility for organizing their social activities. Du Pont was more interested in meeting the needs of the operations personnel who were settling down in Richland. In contrast to “building craftsmen” who were “accustomed to short employment [and] high wages, operations employees were supposedly “older, usually married and possibly with a family of two or three children.” Their “primary interests” were a “home and its maintenance,” which they wanted to look “as nice as possible.” In that context, it “is the Du Pont policy to lend encouragement to and foster the formation of civil groups in the village and the formation of recreation groups by the inhabitants themselves.”

Colonel Antes recommended a “detailed audit of funds and fiscal procedure,” the recovery of excess profits from a contractor, and the termination of the Association when construction ended. Groves signed off on the findings and recommendations.

The “Met Lab,” directed by Arthur Compton, had demonstrated that a nuclear pile could produce a chain reaction and then be used to produce plutonium. With the Du Pont Corporation secretly building huge piles and reprocessing facilities at Site “W” in Washington state, Compton found supporting roles that “Met Lab” scientists could play, for example, by developing the next generation of nuclear reactors fueled by heavy water (“P-9”). As Compton informed Colonel Nichols, Groves and the Military Policy Committee agreed that a heavy water reactor for producing plutonium would not be authorized “until serious troubles have been encountered with the present graphite plant,” referring to the plans for reactors at the HEW.

Compton relayed what he understood as General Groves’ requirements. They included the construction of a heavy water reactor at the Argonne Forest, outside of Chicago, partly as “a performing experiment designed to test aspects of the W pile at relatively high levels of gamma and neutron radiation.” By June 1944, the Argonne reactor was operational. Groves also requested preparation of a design for a heavy water plant that could produce plutonium. The only reason to build such a plant “during the present war following this design will be presumably in the case of failure of the W plant to give satisfactory results.” Compton observed that “it is hoped that the present war will be over before this investigation can lead to important practical results” that could “have a great effect ... on the post-war military position of the nation.”

The instructions also included what information could or could not be shared with the Canadians, who were already producing heavy water and had plans for developing a heavy water reactor.[21] Compton approved sharing technical data and calculations for developing such reactors and explaining instruments for investigating and constructing heavy water reactors. Not approved was sharing information, such as progress, plans, production capabilities, or technical aspects of the graphite reactor used for producing plutonium or the U.S.’s own plans to produce heavy water.

Groves informed Compton that the Manhattan Project’s Military Policy Committee had decided that the “scope of the heavy water work should not be determined” until after a meeting with the British and the Canadians in Montreal. According to Groves, “our effort should not exceed the construction of a lower-powered heavy water pile for use as a general experimental tool” and as preparation should “it become necessary to carry on rapid development” of such a reactor.

Writing to Major A.V. Peterson, the District Engineer for Oak Ridge, TN, also known as “Site X,” Groves made detailed comments on Compton’s 22 September memorandum (Document 15). For example, regarding the design of a heavy water reactor for producing plutonium, the “effort should be held to the barest minimum.” On Compton’s point five, concerning information exchanges with the Canadians, none “will be undertaken without my prior approval until such time as the definite producers for interchange are established.”

Nichols informed Groves that Major A.V. Peterson had approved Compton’s 22 September memorandum before Groves had sent his comments. He informed Groves that his comments had been “called to the attention of Major Peterson and Dr. Compton with your instructions to modify the program” accordingly.

In this letter to Harold Urey, Compton shared his thinking on the role of heavy water reactors for producing plutonium (49) during and after the war. He took it for granted that there would be a directive to prepare a “satisfactory design” for a heavy water reactor and that the design could be used if needed. He further believed that the 1944 design “will go into construction.”

Compton summarized the discussions that he, Groves, Eugene Wigner, Richard Tolman, and Smyth had with the British in Montreal to discuss “problems of mutual interest in connection with the 49 production program.” Concerning the British experiments on the use of heavy water, “it seemed evident that they were not expecting any results ... that would be used in the present war.” In general, the British “see 49 production as an important factor in determining the balance of military power in the post-war world.” They “are getting ready for full-scale activity ... as soon as immediate demands of the present war permit.”

Compton assumed that the U.S. should not supply the British with “larger quantities of our P-9 since this may be become of importance in our war program.” Believing that U.S. heavy water work “must now be organized around the possibility” that the U.S. will need a heavy water reactor to “pinch-hit in our 49 production program,” he was certain that “immediate post-war developments will call for use” of such plants.

Taking the British point about the relevance of plutonium production to the post-war “balance of military power,” Compton wrote that the “the post-war situation will still be greatly confused and it will remain of prime importance to maintain the country in a supreme military position.” Using the British code word for the nuclear weapons program, Compton was “sure that all of the major powers will be extending themselves to develop the tube-alloy program as far as possible.”

Plainly, he wanted the U.S. to maintain its lead. With the “inherent advantages” of using P-9 for nuclear reactors, “its development will certainly play an important part in this post-war effort.” Compton did not specify the advantages but probably had in mind the possibility that using uranium metal to help fuel the reactor would be less costly than using enriched uranium. In any event, Compton would not give “first place” to use of heavy water reactors to produce 49, “but it must be developed as rapidly as possible.”

Compton’s thinking about the heavy water and nuclear reactor requirements shifted since he had considered the issue during the fall. With plans for building reactors and a reprocessing plant at Hanford underway, he found “the present outlook … [to be] so encouraging that I see no value in introducing a P-9 pile at this time for the purpose of insurance.” Nevertheless, Compton assumed that, for the post-war period, the U.S. would need to develop reactors, some possibly using heavy water, for power production purposes, including powering U.S. Navy ships. To strengthen their post-war position, he believed that the British would take a similar course.

When, during the post-war period, the U.S. developed reactors for power production, plutonium (“49”) would be a “by-product” of nuclear reactor operations. Compton believed that it would be unwise “to complicate” the initial stages of a power development program to require “49 production as a part of the pile operation.” For example, a “power unit for propulsion of a ship should not need to consider whether the 49 that is produced can be recovered.”

Considering whether the United States should cooperate with the British on developing reactors, Compton opined that the U.S. would have to determine whether it was advantageous or not. For example, he observed that it “has frequently been found desirable for a strong industry to collaborate fully on a research level with a weaker industry in development of new products of common interest.” That, he believed, could apply to a U.S.-U.K. collaboration on “pile programs.”

A related issue was the exchange of information with the British. Compton supported exchanges on the “fundamental physics and chemistry of the pile process,” including the properties of plutonium and other products” as well as “the design and construction of power piles in successful operation, as long as the British are ... actively at work in these fields.” But he ruled out information exchanges on such matters as plutonium separation or decontamination, and the “design and construction of piles in the course of development,” perhaps referring to the developments of reactors for producing plutonium.