Uranium electromagnetic isotope separation

In 1929 Lawrence invented the cyclotron, which instrument played (and still plays) an important role in nuclear physics. That work led directly to the award of the Nobel Prize in Physics for 1939, just one of his many honors. During World War II E. O. Lawrence made vital contributions to the development of the atomic bomb holding several high-level appointments in the Manhattan Project. He played an influential role in the decision to develop and later employ electromagnetic methods for uranium isotope separation (Calutrons) during the early 1940s. (Photo credit http //wikipedia.org, public domain)... 

When the gaseous diffusion plant came into operation, the cost of separating U electromagnetically was found to be higher, and in 1946, the Y-12 plant was taken off uranium-isotope separation. Some of this equipment is now beii used to produce gram quantities of partially separated isotopes of most of the other polyisotopic elements, for research uses. These units have also been used to separate artificially produced isotopes, such as U from irradiated uranium, and the various plutonium isotopes. 

Improved electromagnetic processes. Developments in plasma physics and magnet design in the 30 years since the Y-12 plant was taken off uranium isotope separation have caused many groups to reexamine electromagnetic processes for separating uranium isotopes, some of which reported at the London Conference on Uranium Isotope Separation [B20]. In the United States... 

The whole uranium work was completely reorganized early in December 1941. Lawrence took over the work on isotope separation by electromagnetic methods, Urey the isotope separation by chemical methods such as diffusion, centrifuging, etc, and Compton was assigned the methods of nuclear physics. Compton s work was to extend originally not only to the establishing of a nuclear chain reaction but also to the final use of the product. It will be seen that the second task was transferred around June 1942 to Oppenheimer s group. 

The firsf uranium isotope separation operations took place at Y-12 in Fall 1943 using the electromagnetic process. The uranium fuel used in the Hiroshima bomb came from that operation. Within another year the gaseous diffusion process at K-25, a backup gamble, was proven to be a workable process and, being a continuous rather than batch operation, it was much less expensive. Y-12 was therefore shut down in December 1946. 

Because of its use in the Manhattan Project, the details of the electromagnetic isotope enrichment process were highly classified. After the discontinuation of its use for enrichment of uranium, much of the related technology was declassified and made available to the rest of the world through conferences and technical publications. Many countries developed their own electromagnetic isotope enrichment capability, but much smaller in scale. While the individual separators were similar in size and design, the number of separators, and thus the total production capability, was much smaller. Russia pursued a course similar... 

The electromagnetic separation plant built during World War 11 at Oak Ridge, involved two types of calutrons, alpha and beta. The larger alpha calutrons were used for the enrichment of natural uranium, and the beta calutrons were used for the final separation of U from the pre-enriched alpha product. For the electromagnetic separation process, UO was converted into UCl [10026-10-5] with CCl. The UCl was fed into the calutron for separation. The calutron technique has been used to separate pure samples of and stable isotopes of many other elements. The Y-12 calutron... 

The foregoing discussion fairly well demonstrates that on a small scale any desired Isotope can be separated either by the electromagnetic or the thermal diffusion method. In contrast to these laboratory-scale processes, the separations of the heavier Isotope D, of the lightest element, hydrogen, and of the lighter Isotope 235u, of the heaviest natural element uranium, are carried out on a literally enormous Industrial scale. 

Determination of uranium in soil samples can be carried out by nondestructive analysis (NDA) methods that do not require separation of uranium (needed for alpha spectrometry or TIMS) or even digestion of the soil for analysis by ICPMS, ICPAES, or some other spectroscopic methods. These NDA methods can be divided into passive techniques that utilize the natural radioactive mission (gamma and x-ray) of the uranium and progeny radionuclides or active methods where neutrons or electromagnetic radiation are used to excite the uranium and the resultant emissions (gamma, x-rays, or neutrons) are monitored. In many cases, sample preparation is simpler for these nondestructive methods but the requiranent of a neutron source (from a nuclear reactor in many cases) or a radioactive source (x-ray or gamma) and relatively complex calibration and data interpretation procedures make the use of these techniques competitive only in some applications. In addition, the detection limits are usually inferior to the mass spectrometric techniques and the isotopic composition is not readily obtainable. 

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