Part 3

Since fusion of light nuclei is produced by extremely high temperatures, fusion events are called _thermonuclear reactions_. The possibility of bringing about thermonuclear reactions on earth to serve as a source of energy has naturally attracted much attention.

In spite of the fact that fusion of ordinary hydrogen atoms (each of which has one proton as its nucleus) supports the activity of the sun, this particular reaction seems to occur much too slowly to be usable on earth. Other isotopes of hydrogen, called deuterium and tritium, however, which contain one and two neutrons in their nuclei, respectively, fuse much more rapidly and seem to be potential earthly sources of controlled thermonuclear energy.

The first large-scale application of thermonuclear energy was the so-called hydrogen bomb, or “H-bomb.” For a brief time an exploding fission bomb develops a temperature of hundreds of millions of degrees Fahrenheit, hot enough to cause some light nuclei to fuse. In the hydrogen bomb, light nuclei of deuterium and/or tritium are exposed to this temperature during such a fission explosion. The resulting fusion of these nuclei causes the explosion to be hundreds of times more powerful than that of the fission device alone. In 1952 the Atomic Energy Commission test-fired such a thermonuclear device at Eniwetok Atoll in the Pacific Ocean. The energy released by the highly efficient device produced an explosion that completely destroyed the coral islet where it was detonated.

At such extreme temperatures all atoms are stripped of electrons; the resulting mixture of nuclei and free electrons is called a _plasma_. Several laboratories are now working on the problems connected with creating and containing plasma. Ordinary solid containers cannot be used. On contact with plasma they would instantly vaporize and would cool the plasma below the temperature necessary for fusion to occur. Fortunately, however, the particles that make up a plasma, being charged electrically, respond to forces in a magnetic field. A strong magnetic field of proper shape exerts a large confining pressure on a body of plasma in a high-vacuum chamber. Thus plasma can be contained in a small volume well removed from the walls of the chamber by surrounding the chamber with suitably designed large magnets or solenoids to create a “magnetic bottle.” In addition, a sudden increase in the intensity of the field can compress the plasma; this compression raises the temperature of the plasma to near that required for fusion.

Fusion of light nuclei would be a much “cleaner” source of energy for peaceful purposes than fission of heavy ones, because the “ashes” of fission reactions are radioactive while those of fusion (helium atoms) are not. Great technical difficulties must be overcome, however, before a controlled thermonuclear reaction is possible. Fusionable material must be heated to a temperature of over 100 million degrees Fahrenheit and must be contained long enough for an appreciable amount of fusion to occur.

The greatest problem encountered to date is the extreme instability of the plasma and the corresponding difficulty of maintaining it at the proper temperature longer than a few millionths of a second. Many physicists now think that the successful exploitation of thermonuclear energy will not occur for many years. When and if it is achieved, however, the deuterium present in the oceans of the earth will represent an almost inexhaustible source of energy.

Isotopes Have Many Uses

The ability to produce and control nuclear reactions is affecting, and will doubtless continue to affect, human life in two outstanding ways. One way is by making tremendous amounts of energy available, either as explosions or as energy released from controlled reactions for peacetime use. The other way is by producing a vast variety of radioactive isotopes, first in the particle accelerators (“atom smashers”) mentioned earlier, and now in large quantities in nuclear reactors.

The presence of a radioactive isotope can be detected by instruments like the familiar Geiger counter; for this reason isotopes make wonderful tracers. These telltale atoms, which, in effect, continually cry “Here I am,” can trace the course of a chemical element through any kind of chemical reaction. Chemists are taking advantage of this new way of tagging atoms to study reaction patterns that, heretofore, have been obscure.

As a consequence, a scientist’s ability to synthesize scarce chemicals is being increased. The exact role of numerous essential trace elements in the growth and metabolism of living things, including people, is being studied by the use of tagged atoms.

Radioisotopes at Work

As sources of radiation, radioactive isotopes are frequently replacing more expensive and less convenient sources such as radium and X-ray machines. The medical treatment of diseased tissue has been greatly expedited by the new sources. In industry many applications of radiation sources have been made. They are used, for example, in thickness gauging and in making radiographs to check the quality of large castings. The sterilization and preservation of food is another promising use for inexpensive radioactive sources.

As a controllable means for inducing genetic mutations, radioactive isotopes are speeding up the process of selecting and developing superior agricultural products. Practically every agricultural research center in the world has one or more projects under way which involve the use of isotopes.

Small devices have also been constructed which produce electricity from heat generated by decay of radioisotopes. Such devices have been used to power instruments in a remotely located unmanned weather station, a navigational buoy, a lighthouse, an underwater navigational beacon, and space satellites. Many additional uses are foreseen for these isotopic power generators.

The Atomic Energy Commission

Following the end of World War II a vigorous controversy developed as to whether atomic energy development in the United States should continue under military control or be transferred to civilian control. The proponents of civilian control won out, and a civilian Atomic Energy Commission was established by the Atomic Energy Act of 1946. Under this Act, which was amended in 1954, the AEC manufactures nuclear weapons for the armed services; produces fissionable materials for both military and civilian purposes; fosters research and development in the basic sciences underlying atomic energy and in applications such as power production and uses of radioisotopes; regulates the activities of private organizations using atomic energy; and distributes information about atomic energy. (This booklet is a small example; most of the information distributed is much more detailed and technical.)

Almost all of the AEC’s materials production and research and development activities are carried out under contract by other organizations. American industry, universities, and research organizations also are engaged in widespread atomic energy activities of their own, subject only to such government regulations as are needed to protect national security and public health and safety. For example, the largest atomic electric power plants now in operation in this country are privately owned, as are numerous small atomic reactors used for research. At the end of 1962 some 7000 firms, institutions or individuals in the United States held federal or state licenses giving them permission to use radioisotopes. The number of persons employed in atomic energy work in the United States is estimated to be about 140,000, of which only 8000 work for the Federal Government.

Toward an International Atom

In December 1953, President Eisenhower, in a memorable address to the General Assembly of the United Nations, proposed the establishment under the aegis of the United Nations of an International Atomic Energy Agency “to serve the peaceful pursuits of mankind.” This proposal captured the imagination of people everywhere, and negotiations soon began as to the purpose, structure, scope, and program of such an organization. In October 1956 an 81-nation United Nations conference unanimously adopted a statute for the agency, which came into existence a year later with headquarters in Vienna, Austria. By the end of 1962 the IAEA had 78 member countries. Its most important work has been assisting some of the less developed nations of the world to begin programs for peaceful use of atomic energy.

Even before the international agency became an accomplished fact, the United States sought on its own to implement the spirit of President Eisenhower’s proposal. It initiated in 1955 an Atoms-for-Peace Program under which the United States has made bilateral agreements with some 40 nations for the sharing of information on peaceful uses of atomic energy and under which the United States has helped other nations to acquire nuclear reactors and materials for peaceful use.

Mention should also be made of the International Conferences on Peaceful Uses of Atomic Energy which the United Nations held in Geneva, Switzerland, in 1955, 1958, and 1964. The 1955 conference was particularly noteworthy in that it marked the first time that scientists had met on a worldwide basis to discuss atomic energy. At and following this meeting much information previously kept secret was made public.

Suggested References

Books

_Atomic Energy_, Irene D. Jaworski and Alexander Joseph, Harcourt, Brace and World, Inc., New York 10017, 1961, 218 pp., $4.95.

_Atompower_, Joseph M. Dukert, Coward-McCann, Inc., New York 10016, 1962, 127 pp., $3.50.

_Atoms Today and Tomorrow_ (revised edition), Margaret O. Hyde, McGraw-Hill Book Company, New York 10036, 1966, 160 pp., $3.25.

_Basic Laws of Matter_ (revised edition), Harrie S. W. Massey and Arthur R. Quinton, Herald Books, Bronxville, New York 10710, 1965, 178 pp., $3.75.

_Building Blocks of the Universe_ (revised edition), Isaac Asimov, Abelard-Schuman, Ltd., New York 10019, 1961, 380 pp., $3.50 (hardback); $2.70 (paperback) from E. M. Hale and Company, Eau Claire, Wisconsin 54701.

_Elements of the Universe_, Glenn T. Seaborg and Evans G. Valens, E. P. Dutton and Company, Inc., New York 10003, 1958, 253 pp., $4.95 (hardback); $2.15 (paperback).

_Inside the Atom_ (revised edition), Isaac Asimov, Abelard-Schuman, Ltd., New York 10019, 1966, 197 pp., $4.00.

_Introducing the Atom_, Roslyn Leeds, Harper and Row, Publishers, New York 10016, 1967, 224 pp., $3.95.

_Peacetime Uses of Atomic Energy_ (revised edition), Martin Mann, The Viking Press, New York 10022, 1961, 191 pp., $5.00 (hardback); $1.65 (paperback).

_The Useful Atom_, William R. Anderson and Vernon Pizer, The World Publishing Company, Cleveland, Ohio 44102, 1966, 185 pp., $5.75.

_Secret of the Mysterious Rays: The Discovery of Nuclear Energy_, Vivian Grey, Basic Books, Inc., Publishers, New York 10016, 1966, 120 pp., $3.95.

_The Heart of the Atom: The Structure of the Atomic Nucleus_, Bernard L. Cohen, Doubleday and Company, Inc., New York 10017, 1967, 120 pp., $3.95 (hardback); $1.25 (paperback).

_The Questioners: Physicists and the Quantum Theory_, Barbara L. Cline, Thomas Y. Crowell Company, New York 10003, 1965, 274 pp., $5.00.

_The Atom and Its Nucleus_, George Gamow, Prentice-Hall, Inc., Englewood Cliffs, New Jersey 07632, 1961, 153 pp., $1.95.

_The Atomic Energy Deskbook_, John F. Hogerton, Reinhold Publishing Corporation, New York 10022, 1963, 673 pp., $11.00.

_Atomic Energy Encyclopedia in the Life Sciences_, Charles W. Shilling (Ed.), W. B. Saunders Company, Philadelphia, Pennsylvania 19105, 1964, 474 pp., $10.50.

_Atoms for Peace_ (revised edition), David O. Woodbury, Dodd, Mead and Company, New York 10016, 1965, 275 pp., $4.50.

_Manhattan Project_, Stephane Groueff, Little, Brown and Company, Boston, Massachusetts 02106, 1967, 372 pp., $6.95.

_The New World, 1939/1946_, Volume 1—History of the United States Atomic Energy Commission, Richard G. Hewlett and Oscar E. Anderson, Jr., The Pennsylvania State University Press, University Park, Pennsylvania 16802, 1962, 766 pp., $5.50.

_Sourcebook on Atomic Energy_ (third edition), Samuel Glasstone, D. Van Nostrand Company, Inc., Princeton, New Jersey 08540, 1967, 883 pp., $9.25.

_The World of the Atom_, 2 volumes, Henry A. Boorse and Lloyd Matz (Eds.), Basic Books, Inc., Publishers, New York 10016, 1966, 1873 pp., $35.00.

Motion Pictures

Available for loan without charge from the AEC Headquarters Film Library, Division of Public Information, U. S. Atomic Energy Commission, Washington, D. C., and from other AEC film libraries.

Each of the following motion pictures explains atomic structure, fission, and the chain reaction. Additional contents are listed below with the film.

_A Is for Atom_, 15 minutes, sound, color, 1964. Produced by the General Electric Company. This film discusses natural and artificially produced elements, stable and unstable atoms, principles and applications of nuclear reactors, and the benefits of atomic radiation to biology, medicine, industry, and agriculture. (Level: elementary through high school.)

_Atomic Energy_, 10 minutes, sound, black and white, 1950. Produced by Encyclopedia Britannica Films, Inc. The film explains nuclear synthesis and shows how, through photosynthesis, the sun’s energy is stored on earth and released through combustion. (Level: intermediate through high school.)

_Controlling Atomic Energy_, 13½ minutes, sound, color, 1961. Produced by United World Films, Inc. This film gives a summary explanation of the following: radioactive atoms, radioactivity measurement, nuclear reactors, and the production and application of radioisotopes in biology, medicine, industry, agriculture, and research. (Level: 5th through 8th grades.)

_Introducing Atoms and Nuclear Energy_, 11 minutes, sound, color, 1963. Produced by Coronet Instructional Films. This film discusses nuclear fusion in the sun and, very briefly, the uses of nuclear energy. (Level: 4th through 9th grades.)

_Atomic Physics_, 90 minutes, sound, black and white, 1948. Produced by the J. Arthur Rank Organisation, Inc. This film discusses in detail the history and development of atomic energy with emphasis on nuclear physics. Dalton’s basic atomic theory, Faraday’s early electrolysis experiments, and Mendeleev’s periodic table, the investigation of cathode rays, discovery of the electron, how the nature of positive rays was established, and the discovery of X rays are among the historical highlights. Explanation is presented of the work of the Joliot-Curie’s and Chadwick in the discovery of the neutron, and the splitting of the lithium atom by Cockcroft and Walton. Einstein tells how their work illustrates his theory of equivalence of mass and energy. (Level: high school.)

_Unlocking the Atom_, 20 minutes, sound, black and white, 1950. Produced by United World Films, Inc. This film explains the properties of alpha, beta, and gamma rays, cyclotrons, and the contributions of various scientists. (Level: junior and senior high school.)

This “Understanding the Atom” series of semi-technical lecture films is designed for inclusion in a high school senior-level chemistry or physics course, or it could be used as an introductional unit in nuclear science at the college level. The films all have sound and are in black and white.

_Alpha, Beta, and Gamma_, 44 minutes, 1962. _Radiation and Matter_, 44 minutes, 1962. _Radiation Detection by Ionization_, 30 minutes, 1962. _Radiation Detection by Scintillation_, 30 minutes, 1963. _Properties of Radiation_, 30 minutes, 1962. _Nuclear Reactions_, 29½ minutes, 1963. _Radiological Safety_, 30 minutes, 1963.

FOOTNOTES

[1]For more information about these devices, see _Accelerators_, a companion booklet in this Understanding the Atom series.

[2]For more information, see _Synthetic Transuranium Elements_, another booklet in this series.

[3]The designation ²³⁵U is a new format, now in international usage, for the more familiar style, U²³⁵, to designate isotopes.

[4]For more about plutonium, see _Plutonium_, a companion booklet in this series.

[5]For more information on reactors, see _Nuclear Reactors_, another booklet in this series.

Transcriber’s Notes

—Silently corrected a few typos.

—Retained publication information from the printed edition: this eBook is public-domain in the country of publication.

—In the text versions only, text in italics is delimited by _underscores_.