Isegoria

The first uranium separation process General Groves looked into, as he explains in Now It Can Be Told: The Story of the Manhattan Project, involved liquid thermal diffusion:

The basic apparatus is a column. It consists of a long, vertical, externally cooled tube with a hot concentric cylinder inside. What makes this an effective separation method is the fact that one isotope tends to concentrate near the hotter of two surfaces, and then moves upward.

From a practical standpoint, thermal diffusion was not suitable as an independent process because of the incredibly large amount of steam required. The production costs would have been staggering. A minimum rough estimate was two billion dollars, and I would not have considered this a safe figure, but would have raised it to at least three billion if I had thought the work would have to be undertaken.

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However, in June of 1944, Oppenheimer suggested to me that it might be well to consider using the thermal diffusion process as a first step aimed at only a slight enrichment, and employing its product as a feed material for our other plants. As far as I ever knew, he was the first to realize the advantages of such a move, and I at once decided that the idea was well worth investigating.

Just why no one had thought of it at least a year earlier I cannot explain, but not one of us had. Probably it was because at the time the thermal diffusion process was studied by the MED we were thinking of a single process that would produce the final product. No one was considering combining processes.

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To expedite the design and construction, I ordered that, insofar as possible, all process features of our plant, particularly the basic column assemblies, should be Chinese copies of those at the Philadelphia pilot plant. A great deal of time was also saved by frequently using field engineering sketches instead of the customary more formal drawings.

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The basic piece of equipment was the isotope separation column, 102 of which were arranged to form an operating unit which we termed a “rack.” The column was a vertical pipe, forty-eight feet long, of nickel pipe surrounded by a copper pipe. The copper pipe was encased in a water jacket contained in a four-inch galvanized-iron pipe. The copper pipe was cooled with water at a moderate temperature. The columns were arranged in three groups, each of seven racks, making a total of 2,142 columns.

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Sixty-nine days after the start of construction, one-third of the plant was complete, and preliminary operation began.

A Chinese copy, by the way, is an exact imitation or duplicate that includes defects as well as desired qualities. The term goes back to 1844.

The electromagnetic process they implemented at Oak Ridge entailed a number of special hazards, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), because uranium is toxic as well as radioactive:

Some of the raw materials were also extremely difficult to handle. High temperatures and pressures were involved and many irritants such as phosgene had to be used. Liquid nitrogen was used in large quantities at a temperature of –196° Centigrade. Huge amounts of electricity were used throughout the process. Each control cubicle, for example, of which there were ninety-six for each alpha track and thirty-six for each beta, consumed about as much electricity as a large radio station.

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We had eight fatal accidents in all of our plant operations through December, 1946. Five people were electrocuted, one was gassed, one was burned and one was killed by a fall.

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Despite all the difficulties that had to be overcome, the first shipment of enriched uranium was sent to Los Alamos in March, 1944, just a few days more than a year after the construction of the plant was begun.

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The chemical side of the electromagnetic process, in fact of the entire project, has often been treated as a simple auxiliary to its more eye-catching atomic physics aspects. Actually, chemistry was the beginning and the end of each of the separation processes. Production efficiency could be won or lost in chemistry, as well as in physics. Each was indispensable.

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The gaseous diffusion process, later termed the K-25 project, was a large scale multistage process for the separation of U-235 from U-238 by means of the principle of molecular effusion. The method was completely novel. It was based on the theory that if uranium gas was pumped against a porous barrier, the lighter molecules of the gas, containing U-235, would pass through more rapidly than the heavier U-238 molecules. The heart of the process was, therefore, the barrier, a porous thin metal sheet or membrane with millions of submicro-scopic openings per square inch. These sheets were formed into tubes which were enclosed in an airtight vessel, the diffuser. As the gas, uranium hexafluoride, was pumped through a long series, or cascade, of these tubes it tended to separate, the enriched gas moving up the cascade while the depleted moved down. However, there is so little difference in mass between the hexafluorides of U-238 and U-235 that it was impossible to gain much separation in a single diffusion step. This was why there had to be several thousand successive stages.

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Without question the most serious problem that confronted us throughout was our inability to produce until late 1944 the barrier material which was the heart of the process. This prevented the orderly installation of the production equipment. It meant that before the first unit could be put in operation, some $200 million had been spent on construction and on the purchase of special equipment, and most of this had been done before we knew even that a satisfactory barrier could be made in the quantities we would require. Yet in spite of this major unknown factor, we had to press ahead with the construction of one of the largest industrial plants ever built, comprising over forty acres of floor space.

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The Oak Ridge plant was a first in every sense, and its design, involving many acres of barrier, was based on this small piece less than two square inches in area. Even this practical foundation soon disappeared when it became known that the material used in the first filter could never be employed in the main plant.

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Finally, after warning us that they were so overloaded with war work that he did not see how they could possibly undertake it, he consented to our talking with his chief engineer. We were amazed when, after we had described in some detail the exacting performance specifications, he replied, “Yes, we can do that. We have already manufactured pumps of the same type, but of course of much smaller capacity.” The contract was accepted and perfectly performed.

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In our hotel rooms we talked at some length about another design problem: how to handle a breakdown within a particular unit. In the course of the discussion, I expressed surprise that it was thought to be a problem, since all that was necessary was to cut out the particular unit that had broken down. The difference between the makeup of the gas varied from diffuser to diffuser so slightly as to be un-noticeable and almost unmeasurable, and I asked how the diffusers could ever tell the difference. That casual question immediately suggested the answer. As so often occurs, it was a case of a simple solution occurring immediately to someone who had not been struggling for months with the problem.

To minimize the effects of gas corrosion, it was first proposed that we use solid nickel for the some hundred miles of process piping. K. T. Keller, the head of the Chrysler Corporation, which was to produce the diffusing units, pointed out that our demands in that case would exceed the entire nickel production of the world, and insisted that heavy nickel plating on the inside of the larger pipe, four inches and above, was feasible. To attempt to heavily nickel-plate the interior of the quantity of pipe we needed was an unprecedented undertaking, but it was solved by a small manufacturer in Belleville, New Jersey, the Bart Laboratories. They developed a novel method in which they used the pipe itself as an electroplating tank. The pipe was rotated during the operation in order to obtain a uniform thickness of deposit. Their success eliminated what otherwise would have been a most difficult situation.

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We had to be absolutely sure that in the hundreds of miles of piping the total leakage of air into the system, particularly through the welds, would not exceed that which would enter through a single pinhole. This problem was solved by industrial engineers. By using helium gas with an improved mass spectrometer, we were able to detect all leaks before the individual piping assembly was installed, and because we could not permit any leakage, no matter how slight, we could not tolerate normal commercial shop welding of the pipe connections, so special welding techniques had to be developed.

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The cleaning and conditioning of equipment prior to installation was vital and the closest practical approach was made to surgical conditions. This involved the complete removal of dirt, grease, oxide, scale, fluxes and other extraneous matter. Any such material, even in small amounts, could very well have caused a complete failure.

The cleaning methods were based on procedures developed by the Chrysler Corporation. The individual steps were not too unusual in industrial practice, but the combination of all of them, their rigorousness and their application to the thousands of pieces of equipment were unheard of.

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All workers changed into clean outer clothing from head to foot upon entering a restricted building.

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Everything possible was done to eliminate dirt and dust. Vacuum cleaners were used instead of brooms, and dust mops were used in order to avoid raising dust by dry sweeping.

Apart from the plutonium plant at Hanford, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), the heart of the effort to produce material for a fission bomb was Oak Ridge:

Here were located all our uranium separation plants — the plants designed to separate the easily fissionable Uranium-235 from the more abundant but much less fissionable isotope, Uranium-238. There were a number of ways we thought this could be done, but for practical reasons, to suit our immediate purposes, they were whittled down to two, the electromagnetic process and the gaseous diffusion process.

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We had decided at the start that the several uranium process plants at Oak Ridge should be well separated, so that in case a disaster struck one it would not spread to or contaminate the others. For that reason, the electromagnetic and gaseous diffusion plants were located in valleys some seventeen miles apart. Later, when the thermal diffusion plant was built, we had to disregard this policy and put it quite near the steam-generating plant for the gaseous diffusion process, in order to take advantage of its supply of extra steam.

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It is a physical rather than a chemical process, although a great deal of chemistry is involved in the handling of the material. Basically, electromagnetic separation of isotopes is based on the principle that an ion describes a curved path as it passes through a magnetic field. If the magnetic field is of constant strength, the heavier ions will describe curves of longer radii. Therefore, the various isotopes of an element, since they differ in mass, can be isolated and collected by such an arrangement.

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Rather early in the American effort, Lawrence had proved to his own satisfaction that electromagnetic separation was feasible, but he stood almost alone in this optimism. The method called for a large number of extremely complicated, and as yet undesigned and undeveloped, devices involving high vacuums, high voltages and intense magnetic fields.

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Dr. George T. Felbeck, who was in charge of the gaseous diffusion process for Union Carbide, once said it was like trying to find needles in a haystack while wearing boxing gloves.

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The first estimate for construction alone was for an unrealistic sum of between $ 12 and $ 17 million; soon afterward this was increased to $35 million. These figures were for a plant much smaller than the one we finally built. In its first report to President Roosevelt early in December, 1942, the Military Policy Committee estimated the cost of the entire project as of the order of $ 400 million. At that time we thought that over $100 million would be needed for this process as a whole.

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Exclusive of the value of silver borrowed from the Treasury for electrical conductors, the construction costs, by December 31, 1946, totaled $304 million; research cost $20 million, the engineering $6 million and operation $204 million. The cost of operating power was almost $10 million.

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Originally we had thought we would need a work force of 2,500. This was a sad underestimate, resulting from our inability to anticipate how complex and difficult the job would be and how many units would be needed. Eventually we had over 24,000 on the payroll.

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We could not permit or even consider the unionization of the operating forces of any of the plants turning out U-235 because we simply could not allow anyone over whom we did not have complete control to gain the over-all, detailed knowledge that a union representative would necessarily gain.

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Later, when our needs grew even more pressing, we were unable to find enough pipe fitters to maintain our schedule. Investigation showed that there simply were not enough in the United States to fill the demands. The solution we adopted was to locate a considerable number of pipe fitters, all union members, who had been inducted into the Army. These men were given the opportunity to be furloughed to the inactive reserve on condition that they would accept employment at Hanford as civilians at the going rates of pay.

When they arrived they were kept together as a group so that their output would not be held down by the pressure of any union officials or of the men already working there. In a direct comparison on identical work, they produced about 20 per cent more than the other men. Pressure was brought on them to slow down, but they refused. A typical comment was: “I’m not working as hard as I did in the Army, nobody’s shooting at me, I’m being paid a lot more and, what’s more important, I’ve a lot of friends in my old outfit that I hope to see come back alive.” As time went on, the other men were apparently shamed into greater effort, with the result that their output went up about 10 per cent.

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On my next visit to Oak Ridge I talked for five or ten minutes to some two thousand of these men. I was not introduced by name but merely as the general in charge of the work for the War Department. The reason for this was to avoid drawing attention to me personally; this was our policy throughout the project until security no longer required it. (My wife once commented that I was undoubtedly the most anonymous major general in the history of the United States Army.)

As simply as possible, I told the group that, as the officer in charge, I could state positively, both officially and personally, that their work was of extreme importance to the war effort, and that my views were a true reflection of those of the Chief of Staff, General Marshall, of Secretary of War Stimson and of President Roosevelt. I added that they could see for themselves how important it was from the terrific effort we were making, our obviously enormous expenditures in money and labor, and our evident ability to obtain materials that were in critically short supply. I said nothing about what we were working on or our hope that its success would quite possibly end the war. There was no flowery oratory; I would have been incapable of it, and it certainly would not have appealed to the audience.

Creedon estimated that after this meeting the efficiency of his construction operations improved by as much as 15 to 20 per cent. I never quite believed this, but the progress reports did indicate an increase of well over 10 per cent. This was far beyond anything I had anticipated; indeed, I would have been pleased with any improvement at all.

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Although we were certain sabotage was not involved [in the “snag” with the magnets on the “race track”], in our detailed review of the situation we found that it would be possible for a saboteur, who would have to be an employee on one particular assignment, to throw iron filings into a feed opening in the oil circulation system and thus put an entire section of track out of action. Steps were taken at once to station counterintelligence agents on and around these spots.

One difficulty, which was unforeseen, because we lacked experience with magnets of such enormous power, was that the magnetic forces moved the intervening tanks, which weighed some fourteen tons each, out of position by as much as three inches. This put a great strain on all the piping connected to them. The problem was solved by securely welding the tanks into place, using heavy steel tie straps. Once that was done, the tanks stayed where they belonged.

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Other substances that had previously had very limited application were needed in staggering quantities. For example, each alpha track used four thousand gallons of liquid nitrogen every week.

One incident that delayed production on a bin in an alpha track for several days involved a mouse. In some unknown way, he got into the vacuum system, where his presence prevented the bin from reaching the necessary high vacuum. After several days of trouble-shooting failed to reveal the source of the trouble, the run was terminated and the bin opened. The remains of the mouse, a bit of fur and a tail, disclosed what had caused the trouble, but no one ever learned how he got into the system in the first place.

More serious in effect was the suicidal action of a bird which perched on an outside wire in such a way as to short the electrical system. We had to shut down an entire building, and, because of the nature of the process, it was several days before operations again became normal.

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Waste such as piping, scrap cloth, filter cloths, papers, rubber gloves, clothing and the like had to be carefully saved in order to recover the small concentrations of uranium, particularly of Uranium-235.

I don’t know if you caught that passage about the costs: “Exclusive of the value of silver borrowed from the Treasury for electrical conductors, the construction costs, by December 31, 1946, totaled $304 million; research cost $20 million, the engineering $6 million and operation $204 million. The cost of operating power was almost $10 million.”

Exclusive of the value of silver borrowed from the Treasury for electrical conductors?

Preliminary design calculations on the Y-12 electromagnetic plant in the summer of 1942 had indicated that enormous quantities of conductor material would be required. Because the demands for copper to be used in defense projects far exceeded the national supply, the Administration had decided that the need for copper should be reduced by substituting for it silver borrowed from the Treasury Department.

Colonel Marshall thereupon called on the Under Secretary of the Treasury, Daniel Bell. Mr. Bell said that he might be able to make available some 47,000 tons of free silver, together with 39,000 tons more which could be released from the backup of silver certificates, if Congress authorized its use through appropriate legislation. At one point early in the negotiations, Nichols, acting for Marshall, said that they would need between five and ten thousand tons of silver. This led to the icy reply: “Colonel, in the Treasury we do not speak of tons of silver; our unit is the Troy ounce.”

Under the terms of the final agreement, the silver required by the project was to be withdrawn from the West Point Depository. Six months after the end of the war an equal amount of silver would be returned to the Treasury. It was further agreed that no information would be given to the press on the removal of the silver, and that the Treasury would continue to carry it on their daily balance sheets. Our relations with the Treasury were most cordial, and Mr. Bell and the various officials of the Mint and the Assay Office were always very pleasant and helpful.

Because of the natural reluctance of any private company to accept the responsibilities for safeguarding and accounting for the large amounts of silver that were involved, the MED had to carry out this responsibility with its own forces. This meant organizing separate guard and accountability units, establishing special inspection procedures employing special consultants and arranging to convert the silver into the conductors that we so urgently needed.

We accepted the Treasury’s certification of the bar weights of the silver as we took it over at West Point. Then we delivered it to a processor, who cast the bullion bars into billets which could be extruded into forms more suitable for manufacture into bus bars, magnet coils and similar items. The casting was done by the Defense Plant Corporation and by the U.S. Metal Refinery Company. For the large magnets which used the bulk of the silver, Phelps Dodge Copper Products Company then extruded the billets into strips, which were rolled into coils about the size of a large automobile tire. These coils were shipped to Allis-Chalmers, where they were wound, suitably insulated, around the steel bobbin plate of the magnet casing.

Special MED guards watched the silver at all times while it was being processed, and accompanied every shipment except that of the final magnets from Allis-Chalmers to the Clinton works. We decided that at this point we could achieve adequate security by sending unguarded railway cars over different routes on varying time schedules. The silver coils were encased in large, heavy, steel shells which were completely welded together. Although silver is a valuable commodity, to have made away with any great amount of it during shipment would have been a major task, as our experience in opening one of these shells at Oak Ridge later confirmed. Moreover, the railroads always followed our shipments carefully, and we would have known immediately if any car had been waylaid.

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No recovery operation was undertaken unless the recoverable amounts were expected to be of more value than the cost of recovery. Nevertheless, throughout the entire operation we lost only .035 of one per cent of the more than $300 million worth of silver we had withdrawn from the Treasury.

That’s still $105,000, by the way — and back when that meant something.

The average wait for an evacuation from the Ukrainian front is a week, with some taking as long as a month:

Wounded soldiers have died waiting despite being supplied with intravenous fluids and pain relief, he says.

Evacuations are dangerous, and commanders are constantly weighing the risks. In one case, the driver of an M113 armored vehicle sent to rescue a casualty was killed when it was hit by a drone. Six more soldiers were then injured in subsequent missions to rescue the same soldier.

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“We never send people closer than 5km [3 miles] to the front if a robot can do the job,” Eugune says. “We navigate at night using landmarks like trees, towers, and roads. It’s like orienteering.”

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Engineers from the unit have adapted one of its TERMIT ground robots, now known as “Mr. Hook,” to recover marooned UGVs.

“Sometimes it’s simple — an electric cable or debris caught in the tracks, even abandoned village power lines can be a hazard, tangling in the vehicle’s running gear,” Eugene says. “This one’s going to be more difficult, though, the UGV weighs about 120 kilos [265lbs], and with the load it’s carrying, nearly 270 kilos in total.”

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Ruslan uses a Turkish-made Hatsan 12-gauge shotgun for defense against enemy drones.

Once the UGV is on the ground, Vitalik takes control, with Serhii as co-pilot and navigator, and in less than an hour, the robot reaches the frontline, where soldiers quickly emerge from a dugout to retrieve the supplies

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All the hardware and software are built in-house, and it takes about a week to adapt manufacturer-delivered UGVs so they can operate in frontline conditions, Eugene says. GPS often drops out due to Russian jamming, for example, so operators have to navigate visually using the feed from a nearby Mavic drone.

Custom software reduces delays in communication with the vehicles, but there is no standardized national system. Government-issued software is proprietary and slow to obtain, so the unit develops its own to maintain flexibility and adapt quickly to battlefield changes.

Operating UGVs is far more time-consuming than flying First-Person-View (FPV) drones, Eugene says. But while FPV drones can reach their target in minutes, they can only carry light loads.

Baba Yaga drones, for instance, can only carry about 10 kilos and wear out after roughly 100 missions. UGVs move slowly and must navigate terrain obstacles, but can deliver heavy payloads. They cost about $10,000, and Eugune says prices remain high because they are not mass-produced.

“Right now, there are only two viable roads in this sector, which the Russians patrol with drones,” he says. “UGVs are harder to detect because they’re electric and have a low thermal signature.”

The front is no longer a single trench line but, in places, a contested zone up to 15km deep with multiple layers of positions. Eugene says his team can’t cover some forested areas, forcing troops to carry supplies by hand for the last stretch. And the inconsistency of Starlink’s satellite internet connection doesn’t help.

On this mission in the Kharkiv region, the robot is running on a decentralized so-called mesh network rather than solely on Starlink, and the unit sometimes deploys a separate “bicycle penetrator” robot, which carries Starlink or mesh nodes as a forward relay. Typical signal range is about 7km, though a small aircraft carrying a transmitter can extend that to 30km.

On one mission working as a navigator for another unit that relies solely on Starlink, Eugene recalls guiding a UGV carrying a casualty over 1.7km of hostile territory. The trip took two-and-a-half hours because the Starlink connection dropped every five meters, he said.

The route was entirely within the kill zone, where no one could remain in the open, yet the injured soldier had to be moved along a regular road. “It’s just luck the UGV wasn’t destroyed,” Eugene says. “If they ran 100 missions like that, 95 would fail.”

Ukrainian troops are using Latvian-built electric scooters to move quickly, quietly, and off-road:

The Mosphera military e-scooters used by Ukrainian operators are made by Latvian firm Global Wolf Motors, are about twice the size of a regular scooter, and have motorcycle tires, Klavs Asmanis, the founder and CEO, told Business Insider.

These nimble, off-road e-scooters can hit 62 mph, cover up to 186 miles on a single battery charge, and weigh just 163 pounds, making them easier to handle than heavier bikes.

Asmanis said they can make deliveries to the front lines, do reconnaissance in Russia-held territory, and quickly evacuate lightly wounded troops, among other missions, and Ukraine is putting them to work.

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Asmanis said the scooters offer advantages over other vehicles being used in this war. For instance, they are smaller and lighter than traditional vehicles, they don’t drown out the buzzing sound of drones, they’re easier to quickly bail out of in an emergency, and the scooters don’t require risking a car, truck, or other vehicle that could be packed with gear for other missions on quick, daring dashes.

He said they excel in forested areas. “Its e-scooter-style wheelbase makes it easy to weave between trees” and trails, while its 163-pound weight “means that if it does get stuck, it’s far easier to pull out compared to a motorcycle.”

They’re also far easier to hide when not in use, in bushes or under branches.

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Asmanis said his vehicles are better suited to conflict than typical e-scooters, describing them as “in the middle between scooter and motorcycle” because it has much larger wheels, like motorcycles do, than regular scooters.

Peter Turchin and his colleagues ask, What have been the causes and consequences of technological evolution in world history?

Many have argued that the evolution of military technologies is just one aspect of a much broader pattern of technological evolution driven by increasing size and interconnectedness among human societies. Several cultural evolutionary theories, conversely, highlight military technologies as a special case, arguing that steep improvements in both offensive and defensive capabilities of technologies along with accompanying tactical and organizational innovations resulted in “Military Revolutions” (note the plural), which in turn had major ramifications on the rise and, of particular concern here, the spread of state formations globally and the evolution of religion and other cultural phenomena.

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We empirically test previously speculative theories that proposed world population size, connectivity between geographical areas of innovation and adoption, and critical enabling technological advances, such as iron metallurgy and horse riding, as central drivers of military technological evolution. We find that all of these factors are strong predictors of change in military technology, whereas state-level factors such as polity population, territorial size, or governance sophistication play no major role.