The Peacetime Applications of Atomic Energy

The only natural occurring element, from which scientists have learned to release atomic energy, is uranium. But uranium metal consists of atoms having different masses, 0.7% of uranium atoms having a mass of 235 and remaining 99.3% having a mass of 238. It is only the atoms of mass 235 which are fissionable, that is, from which energy is released. There are several types of reactors now in operation in different parts of the world, all using either natural uranium or uranium artificially enriched with uranium 235, or one of the new fissionable elements produced in a reactor. They differ also in the type of coolant used and in the moderator for slowing down the neutrons, which may be either pure graphite or heavy water. You have all seen photographs of such "atomic ovens" in the press and popular magazines. Our Canadian NRX reactor, which uses heavy water as moderator, has been described as that of most advanced design by both British and American authorities. It is provided with experimental facilities which, combined with its high neutron flux density, enable our scientists to perform investigations that would be difficult, if indeed possible, in any other reactor. It operates at an output of 40 million watts, generating the same energy in the form of heat as that required to keep 660,000 ordinary 60 watt electric lights burning continuously! The new NRU reactor now under construction at Chalk River will be even more powerful with several times the flux intensity, and is also provided with facilities for research which will expedite the results of investigations awaiting solution.

Reactors perform three main functions apart from the research facilities specially provided in the Chalk River piles, each of which is susceptible to improvement and useful expansion:

1. They produce a large variety of radioisotopes which offer great opportunities for application in industry, agriculture and medical therapy.
2. They produce vast quantities of heat from small amounts of nuclear fuel. This heat in most cases at present is conveyed by the coolants at low temperatures to rivers or the ocean where it causes only slight local changes in the temperature of the water. It is, however, a potential source of producing steam to generate large quantities of electrical energy.
3. They can produce new nuclear fuel out of non-fissionable material, thus increasing the amount available to supplement the only naturally occurring fissionable element-the 0.7% of uranium which has atomic weight 235.

Much has yet to be learned of the application of all three products of the release of atomic energy. Let us consider the possible applications of each of these fields of atomic energy release in the next decade.

Several hundred new radioisotopes of the previously known elements have been produced in reactors and in addition eight new elements all of atomic weights heavier than uranium have been created, which were not present on our earth 15 years ago. These isotopes emit radiations which are not only detectable and permit quantitative measurement but may be one of three types-atomic particles, electrons and y rays, the latter being short X-rays. When they emit these rays, they decay into other elements, at rates which vary from a fraction of a second to thousands of years, rates which are characteristic of each particular isotope. Already many of these isotopes have industrial uses in radiography of castings, welds and inspection of internal parts of machines-replacing X-ray machines of various penetrating power. Extensive use of cobalt 60, iridium 192, caesium 134 as well as sodium 24, gallium 72 and lanthanum 140 is now an accepted practice. Small portable lead caskets weighing only 20 to 30 lbs. have been developed, which contain isotopes that emit radiations comparable to a 100,000 volt X-ray machine. As no auxiliary equipment is necessary, these units will find many industrial and medical exploratory applications. Other isotopes which emit electrons are at present employed in thickness gauges for controlling the thickness of various pliofilms-paper, rubber or metal sheets. Several hundred such gauges are now in operation in the United States and Canada. Use has also been made of such isotopes for measuring the thickness of tin on tinplate, covering of threads with thin layers of lubricant and in testing the wear of various moving lubricated parts of machines. For many purposes they are by far the most sensitive means of detection and measurement.

Some isotopes emit particles, which when mixed with phosphors produce luminous paints, useful for reading dials, finding switches or house numbers, in the dark. Those which eject energetic rays, nuclei of helium atoms, if mixed with beryllium constitute excellent neutron sources. These are applied in oil well logging.

As tracers in chemical industries or in studies of medical physiological action of hormones, drugs, etc., the particular chemicals can be labelled with a radioactive isotope of the inactive element and thus its particular function followed. One company last year is reported to have saved over $100,000 and another was able to perform with the use of isotopes at a cost of $35,000 what would have meant an expenditure of over $1,000,000 by conventional methods, accomplishing in weeks what might otherwise have taken years. Much information has already been acquired regarding the effectiveness of fertilizers, absorption of nutriment by roots, aquatic plants and creatures, as well as the habits of insects. A limited number of isotopes-cobalt 60, iodine 131, phosphorus 32 and gold 198 have therapeutic values in treatment of diseases.

During the next quarter century we shall have a very large quantity of radioactive fission products in the "ashes" from reactors-so much indeed that the storage or disposal of them will need considerable research. Many of these will perhaps find application in the sterilization of food, drugs and bandages, etc. Preliminary investigations have already shown that heavily irradiated potatoes, for example, retain their fresh state without sprouting over long periods. Radiation may alter the taste or nutrition value of food but biochemists will discover means of eliminating such undesirable results by their research. If radiation be found to prevent deterioration of whole-wheat flour and other vegetable products, fruits, milk and meats, kept at normal temperatures, the application of fission products for such purposes would help solve their disposal. The radiations from isotopes absorbed by plants cause mutations and some of these will probably be found to be beneficial-rust resistant grains, improvement in yields, and more readily harvested. Millions of dollars are being spent each year on medical research into the cause and treatment of cancer, heart disease, arthritis and polio and we may expect that radioisotopes will assist in the solution of their causes and in their treatment.

Radiations are known to assist in promoting polymerization of certain organic compounds and we may expect this property to be developed as an important function in the new petrochemical industries now being established in Canada as a result of modern research and the discovery of large supplies of oil and natural gas in the Western Provinces. When it is recalled, how the discovery of a single catalyst replaced in a few years the whole natural indigo industry by providing a cheaper and better artificial chemical dye, it is not difficult to realize that similar discoveries using radioisotopes may bring about similar changes in industrial products.

The most important application of nuclear fission will undoubtedly be the production of steam for operating conventional turbo-generators to produce electricity and power. The fission of a pound of nuclear fuel releases as much heat as obtained from burning 2,700,000 lbs. of coal, 360,000 gallons of gasoline or about 30 million cubic feet of natural gas. In a reactor using natural or enriched uranium fuel, it is possible to have so much heat generated that the uranium metal will attain any desired temperature up to its melting or even evaporating temperature. However, the uranium metal must be sheathed with some metallic coating to prevent the fission products from entering the coolant, which must be used to remove the heat and also to avoid chemical action of the coolant on the uranium. Since most materials, such as steel, copper and fire-bricks cannot be used owing to their high absorption of neutrons, we are limited at present to a few sheathing materials, such as aluminum, zerconium, beryllium. The sheaths must be good thermal conductors, to remove rapidly the heat from the uranium. Then the coolant must also be a poor absorber of neutrons and be able to carry the heat to heat-exchangers for the production of steam. Furthermore, the fuel, if metallic uranium be used, must be treated in such a way as to reduce any changes in shape, expansion or contraction, which would interfere with the rate of flow of the coolant. Methods of permitting long burning time, with the consumption of a large fraction of the fuel without its removal for chemical processing to withdraw the ashes, which have a "choking" effect, similar to ashes in an ordinary furnace, must be developed.

To overcome many of these metallurgical and chemical problems, numerous types of reactors have been suggested.

Pilot plants have already been constructed in which steam is produced that is used for generating small amounts of electricity. These are experimental units to explore the possibilities of designing larger commercial plants. Electricity was first produced in such a pilot plant in December 1951, and a different design safely generated electricity in February 1953. The first large power plant, which commenced operation last summer, was the nuclear power unit to drive the U.S. atomic submarine "Nautilus." All three nuclear power plants mentioned are in the United States.

The need for more power, owing to the rapid increase in demand for electricity, which is prevalent in all countries, has led to intensive feasibility studies of developing large commercial atomic energy plants to supplement the present hydro and coal-burning sources of energy. Such plants are now under construction in both the United States and in the United Kingdom. These particular nuclear reactors will develop commercial quantities of power and are different in their construction and method of operation. The 60,000 kilowatt plant being built by Duquesne Light Co. near Pittsburgh, will use pressurized water as moderator and liquid coolant. The American Atomic Energy Commission is undertaking a two hundred million dollar programme to design and construct five different experimental types of power plants. Four will produce electricity but it is not expected at a competitive cost with present power producers. Several private American utility companies are now engaged on the design of atomic energy plants with a view to constructing them to augment their supply of electric power, using nuclear fuel to replace coal or oil.

In Great Britain, it is estimated that by 1970 the annual production of coal for power will be short as much as 20 million tons and it is expected that much of this deficiency will be met with nuclear reactors. Atomic energy offers such great opportunities of obtaining large amounts of energy from comparatively small amounts of fuel, it is not surprising that the first major decision to use nuclear fuel in place of coal for the commercial production of electric power is that recently announced by the British Government. According to this programme they will construct, at a cost of 300 million pounds, 12 atomic energy stations to be completed and in operation within ten years. These units are expected to supply about two thousand million watts, equivalent to that produced by burning 5 of 6 million tons of coal annually. The first stations will be graphite moderated, natural or slightly enriched, uranium fuel, gas cooled with carbon dioxide, the heat of which will produce steam to operate a conventional turbo-generating plant. They will be in operation in 1962. The other types will be liquid cooled, four ready by 1963 and the remaining four in 1965. The cost per kilowatt hour is estimated to be 7.5 mills, not much different from the present cost of power from coal-fired units. The experience gained in design and construction, as well as operation of these units, will enable the British to maintain their economy as their supply of coal becomes inadequate and will also provide a basis for possible export based on the knowledge acquired.

Canadian scientists and engineers have not neglected the great possibilities of generating useful power from atomic energy. For more than a year a team of engineers from the Hydro Electric Power Commission of Ontario and other utilities have been engaged with the Chalk River staff on the design of a prototype pilot plant to produce about 20 million watts. It is expected that power from nuclear energy can be generated at a cost competitive with that from coal but such factual knowledge can only be gained by actual experience. The Government has announced that this pilot plant will be built jointly by the Federal Government and the Ontario Hydro, the Canadian General Electric Company doing the design in cooperation with the staff at Chalk River. This unit will be in operation by 1958 and will serve to establish whether the future demands for electrical energy in Ontario will be met by large plants using nuclear fuel as a replacement for coal. Ontario has already used practically all the available sources of hydro electric developments and has had to construct two large steam plants to augment her supply. Even with the coming into performance of the Sir Adam Beck II plant at Niagara, and the completion of the St. Lawrence power development, it is estimated that by 1962 or a few years later, other sources will be required-hence, the interest in producing nuclear energy plants which will be competitive with coal. Furthermore, we have an additional incentive to use nuclear power, since Canada is one of the largest potential sources of the basic nuclear fuel-uranium.

Physicists are optimists, but engineers are courageous also, and many are now learning the fundamentals of modern physics, which adds enthusiasm to their more practical outlook. We may very well have in addition to submarines, ordinary ships and even airplanes using nuclear power. The necessary shielding to protect the personnel is still a requirement which will prevent its use in small units, such as motor cars. Many of the problems requiring solution are chemical and metallurgical. The removal of fission products is necessary for they capture neutrons, are the source of intensive radiation, and if accumulated in any large amounts would probably cause structural changes in the fuel element. Simple, or at least practical, economic methods of dealing with this matter will be developed by chemists and metallurgists.

The fact that a great many countries in Europe, India and South America have not sufficient fossil or hydro resources to meet even half of their present day requirements of power, adds an extra incentive to develop nuclear power. Just as grain research has increased our food supply by both improvement in the type and by developing new kinds which will ripen in the further northern latitudes, so research will provide the means of creating economical nuclear power units.

In a reactor using natural uranium, many neutrons are captured by the uranium atoms of mass 238, forming a new unstable element, neptunium. This element soon decays to a much more stable new element, plutonium, which is a very valuable nuclear fuel-both for reactors and for atomic bombs. Hence every uranium reactor produces this new fuel from the non-fissionable uranium 238. If the metal thorium is exposed in a reactor to neutron bombardment, it may be transformed into a fissionable isotope of uranium having a mass 233. Thus, we can, and do, create nuclear fuels from both uranium and thorium. Each nuclear fission on the average releases 2.5 neutrons. One of these is required to keep the reactor operating at its constant power level. One of the remaining l.5 neutrons might produce an atom of the new nuclear fuel out of the non-fissionable isotope to replace the atom consumed. In other words, the fission of ten atoms of say, unanium 235, will result in the ejection of 25 neutrons. Ten of these are required to fission other 235 nuclei to keep the power constant and ten might be captured by uranium 238 atoms to replace the fuel consumed. This would leave still five neutrons available, some of which will be absorbed by moderator, shields, coolants and reflector and others may escape into the surrounding medium. If a reactor could be designed, so as to conserve one of the remaining neutrons to produce an additional atom of fuel, then we should be gaining more fuel than is consumed. A reactor, which would produce more fuel than it consumes, is called a breeder. Such an experimental breeder has been designed and operated at the National Reactor Testing Station in Idaho with indications that breeding is actually occurring. It is what is called a fast neutron type, using a central core of nuclear fuel surrounded with a blanket of uranium in which the nuclear fuel is produced. The coolant, water under pressure, produces steam for operating a turbo-generator. It is thus also a double purpose type of reactor-producing power and fissionable material.

We may expect improvements in such reactors, affording power and producing nuclear fuel from either uranium or thorium or both. As the 0.7% of uranium is the only natural source, the importance of transforming the large amounts of uranium and thorium to nuclear fuel is a very urgent aspect of nuclear reactor design. All countries are interested in such development. The British hope thus to make available enough nuclear fuel in breeder type reactors which will also produce useful power at or near competitive costs, to make up for their estimated deficiency in coal. Besides coal is much more valuable as a source of chemicals than as a heating fuel and should be conserved for that purpose. It is estimated that the world's supply of conventional fuels and hydro is less than half the energy which uranium and thorium deposits could supply. This estimate assumes breeding, which in a quarter century should be in economic operation.

Small "packet" nuclear plants will be designed for providing power in remote isolated places, such as we have in the north of Canada, where mining and small townsites having a limited life have been established. They would provide the necessary electric power for operations and could also produce the necessary heating facilities. Little has as yet been done in designing such units but they could be operated today at rates competitive with the present cost of diesel supplied power in many northern mining camps. They will be made portable, or at least demountable, so as to be used in successive mining operations. They would have the advantage of small fuel requirements, eliminating the difficulty of transporting and storage of large quantities of oil to provide for winter operations, as is necessary in many localities at present.

Since reactors are merely generators of heat, they will undoubtedly be used as central heating plants for large communities. Their use for this purpose replacing coal and oil, will avoid the smoke nuisance which at times not only presents health hazards but destroys the beauty of our cities. If, as we expect, they will be as economical to build and operate as coal or oil-fired boilers for power purposes, they will be even more useful as heating units for large blocks of buildings. Not only will this be possible in cities and towns but also in remote large camps or industrial plants. However, they will not replace the single house furnace unless such heating be tied in with a large central heating scheme for whole blocks. Larger plants are more economical than small reactors and the minimum size is such as to preclude any domestic use.

More Speculative Possibilities

The results of investigations with radioisotopes, design of economic power reactors and breeders, chemical processing and waste disposal, are all short-term developments which will definitely be beneficial in maintaining and raising the standard of living and health in all nations of the world. This assumes that goodwill and faith in the better judgment of man will restore a peaceful world with the release of the huge stock-piles of fissionable weapon material for the creation of useful power. But there are other much greater sources of atomic energy which will eventually be released at controlled rates on this planet, when research unlocks the secrets of how it may be accomplished. This is the thermonuclear reaction in which hydrogen nuclei combine to form helium by a fusion or synthesis process with the release of an enormous amount of energy compared with that obtained from the fission of uranium 235. It is rather interesting that this idea was expounded by the physicist Bethe about 15 years ago, shortly after the discovery of nuclear fission, to explain the source of energy from the sun. He proposed a series of six nuclear reactions in which carbon acted as a catalyst to combine four hydrogen nuclei to form one helium nucleus. Subsequently other reactions were proposed, such as the reaction of a tritium nucleus on a helium nucleus to form a lithium nucleus which acting on hydrogen produces two helium nuclei, with the release of energy. These speculations required exceedingly high temperatures and large quantitis of materials in nuclear form- atoms stripped of their electrons. Such conditions were not available on our planet until the development of the atomic bomb. It requires temperatures of millions of degrees and such conditions are present in a nuclear explosion. Hence, by adding the appropriate ingredients, a thermonuclear reaction was tested and as is well known today, the reaction actually does occur with a very substantial release of energy. When our scientists learn more about how nuclei are held together, the exact nature of the forces and how the various particles besides protons and neutrons are created by cosmic rays and similar energetic incident particles, it is possible that such thermonuclear reactions will be available at less violent rates. The secret of accomplishing this will undoubtedly be found in the future and then our supply of nuclear fuel will be almost unlimited.

The propulsion of ships and airplanes will in the future be performed by nuclear engines but such developments will not be in general use for at least a half century. The warm water from the condensers of turbo-generators attached to nuclear power plants might very well find useful application.

Today we are living in the dawn of nuclear science. Great possibilities and achievements for the welfare and happiness of mankind lie ahead. We, in Canada, may be justly proud of the contribution our scientists and engineers are making to the peaceful applications of atomic energy. The NRX reactor at Chalk River is recognized as that of most advanced design of any known experimental pile and the new NRU one, now under construction, is not only more powerful but has many new features which will enable our scientists to retain a leading role in the greatest development of modem science, opening up new vistas through which gleam the untravelled world, full of hopes and excitement for all to explore. Never before have such possibilities been offered to mankind to improve his health, happiness and intellectual satisfaction as those now available from the future developments in Atomic Energy.

THANKS OF THE MEETING were expressed by Mr. Arthur E. M. Inwood, a Past President of the Club.