I always used to imagine that, unless you were in the Manhattan Project, or a top military or political leader, that the atomic bomb had come as a great surprise and only after Hiroshima did the average public get to hear of the new nuclear physics. But nothing could be further from the truth. Not just the scientific papers, but magazines like “Popular Science” and “Popular Mechanics” (and, no doubt, many others) were often publishing suprising details about the progress in atomic physics.
This article comes from January 1941 Popular Mechanics Magazine (“written so you can understand it”) and, though wildly optimistic, is perfectly clear about U235 fission, with references to plutonium breeding and isotopic separation:
- Author’s idea of what life may be like in Uranium age. Note that most activities are located underground – even farming. Only transportation and recreation are above the surface.
The Miracle of U-235
SEVERAL months ago you read in Popular Mechanics that the secret of atomic power is close to solution and that possibly within a decade civilization will be using the tremendous amounts of energy contained in U-235, an isotope of uranium.
Since then, additional research has opened up greater possibilities than ever. At first we thought that a heavy power plant weighing tons would be required to extract the power; now it appears that a pound or even a single ounce of U-235 can be made to deliver energy. A power plant the size of a typewriter will be available. Its heart will be a one-pound package of uranium that contains the same amount of power that we extract from 250,000 gallons of gasoline. With such a power pack in a car you could drive 5,000,000 miles without refueling. Obviously, at $1,000 a pound, U-235 will be cheap.
But more miles per dollar is only one minor advantage foreseen for the uranium age. We can look forward to universal comfort, practically free transportation, and unlimited supplies of materials. Power will be cheap in every home and factory, without distribution lines, and electricity will cost less than one-tenth of a cent per kilowatt-hour.
- Dr Langer’s conception of the U-235 automobile
- Author’s idea of U-235 plane, a flying wing with propelling jets at rear and lifting jets underneath.
Postponing explanations for awhile, it is pointed out that water passing over U-235 can be brought almost instantly to a very high temperature and a correspondingly high steam pressure. To utilize this property one need only take over the principle of the flash boiler. Water is passed through a small chamber which contains U-235 in porous form. The chamber may be less than six inches in diameter. The water emerges as high-pressure steam into a series of turbine wheels all solid to the same shaft. Speed depends on the rate at which the steam passes through. A reversing valve may be used to divert the steam flow to an opposite-turning turbine on the same shaft to obtain a braking or reversing action. Complete control is obtained by throttling down or opening up the water supply and exhaust to get less or more power at the same operating pressure.
The driving mechanism of the automobile is now clear. Under the body is a water tank that helps shield the occupants from radiations emitted by the uranium and also puts the center of gravity low. Each wheel hub has on it a very small reversible turbine motor such as the one described. This car needs no differential or clutch. The uranium must be detachable because it probably will outlast the car. Recovering its own exhaust steam, such a car could travel without stopping until it wore out its tires or needed other servicing. Using the newly developed vertical propellers, such a vehicle might be converted into a high-speed, long-range vessel to travel on water, and might be furnished with unfolding wings for travel through the air.
- Aparatus for separating elements into their isotopes
Let’s study the process by which the fabulous amount of energy can be release from U-235. It is not a perpetual-motion scheme. It happens that U-235 is a special kind of uranium so near the point of it stability that any neutron entering breaks it down into entirely different out substances, such as bromine, iodine, barium, krypton, and many others. In the transmutation these products take on rapid motion which is soon transformed into heat. It would take a potential difference of a most 200,000,000 volts to duplicate the energy release. The burning of coal corresponds to about four volts on this scale, some 50,000,000 times feebler the the uranium reaction. The mechanism of our uranium motor is based on that reaction. A few neutrons are constantly being introduced, with the help of radium, into our small box of U-235. There is a regenerative feature that make the reaction continuous. Clever tricks are already known to prevent the process from getting out of hand.
Recently in California it has been learned that the ordinary uranium atoms sometimes can be transformed by neutrons into new atoms which can be split up to give the enormous energy of uranium-235. At Westinghouse it has been discovered that photons, which are like ordinary light but have higher energy, can start the energy chain in U-235. These two discoveries mean that in the process of breaking up U-235 and deriving its energy, the by-product photons and neutrons turn right around and manufacture new material to provide new energy. It is not inconceivable that in practice each U-235 atom that splits will cause a U-238 atom to be transformed into an energy-producing variety. Translating that into simple language, a pound of U-235 would be equivalent to 500,000 gallons of gasoline instead of 250,000 indicated above. At the same time the total equivalent supply of U-235 would be doubled and the things predicted in this article would become twice as easy to attain.
Only one atom in 140 uranium atoms is of the proper kind and the hitch at present is that we haven’t found the most practical method for separating these special U-235 atoms from the rest of the uranium. This is similar to many problems that have been solved in the past, and solution of the problem is foreseen.