Magnesium transmission housings Metal cheaper in Europe
over the price of magnesium and overcapacity. At present Dow can produce 120,000 tons of the metal annually at its Freeport, Tex., mag-fromthe-sea works. UOP's newly acquired Calumet & Hecla subsidiary has 9000 tons of yearly capacity at Selma, Ala. Compare those figures with the 117,000 tons used in the U.S. last year. There's quite a demand gap. Add American Magnesium's 30,000 ton-per-year plant under construction at Snyder, Tex., and National Lead's 45,000-ton plant plus Dow's new unit and a possible one from Kaiser and you get about double the U.S. magnesium capacity by the early 1970's. Could someone be bluffing? The largest potential market for magnesium is die-cast auto parts, now made principally from aluminum. Dow has previously tried to crack the U.S. market without success. However, Dow supplies magnesium to Volkswagen in Europe at 25 cents a pound. The U.S. price is 30 cents. The total potential die-cast market is more than 100,000 tons a year, 10 times the present market. With a lower price and more than one major source, magnesium would have a better chance of invading the die-cast market in autos and appliances. The burning question: Will the market be large enough and develop fast enough to support all proposed and existing plants.
Cryogenic technology boosts linear accelerator capability Two critical properties of matter at cryogenic temperatures—superconductivity and superfluidity—should open the way for a major advance in electron linear accelerator capability. That's the expectation of a group of physicists at Stanford University in Palo Alto, Calif., who are planning the 18 C&EN MAY 6, 1968
installation of a new 500-foot LINAC there. A key factor distinguishing the new accelerator from its forerunners, the Mark I, II, and III, is that it will produce a continuous beam of 2- to 5b.e.v. electrons, instead of the 1-microsecond bursts that emanate from conventional LINAC's. "We expect to achieve a thousandfold improvement in duty cycle, a hundred-fold improvement in energy resolution, and considerably higher energies than now possible in conventional machines of the same length," notes Dr. H. Alan Schwettman, who has been actively working on the project since he joined Dr. William Fairbank at Stanford's low-temperature physics laboratory six years ago. "The unique contribution of superconductivity is that it can reduce dramatically the power needed to sustain the electric fields in the accelerator cavities," he adds. A major drawback to existing LINAC's is the loss of energy the electrons undergo as they pass down the accelerator tube. The loss is due to the high electrical resistance of metal at room temperature. To achieve a continuous beam of electrons, many billions of watts of RF power would be needed to compensate for the dissipation of electrical energy. It's for this reason that the voltage now going to a LINAÇ is pulsed, which in turn produces pulsed electron beams. Dr. Fairbank and Dr. Schwettman plan to overcome this resistivity problem by lining the inner walls of the copper accelerator tube with lead. Alternatively, they may make the tube entirely of niobium. These metals are superconductors above the boiling point of helium. The accelerator tube will be encased in a stainless steel tube filled with liquid helium. At 1.8° K., below the superfluid point, the helium will play a dual role. It will ensure that the metal of the accelerator tube is cold enough to be superconducting. And because liquid helium is superfluid, it will maintain a stable thermal environment within the tube by acting as a highly efficient heat sink. A closed-loop system will permit the helium to be recycled. Additional casings will complete the cryogenic LINAC. A compartment maintained at 10~10 torr will separate the helium container from a heat shield cooled with liquid nitrogen. A second vacuum chamber will separate the heat shield from the atmosphere. The new LINAC will be buried 30 feet underground at Stanford's highenergy physics laboratory where Nobel Laureate Robert Hofstadter and Dr. Mason Yearian are cooperating in the experiment scheduled for 1970.
France faces energy dilemmause own process or go American France may well be facing a moment of truth this month regarding her atomic energy policy. Will she decide to continue going her own way—producing electricity through natural uranium power plants—or will she buy U.S. enriched uranium? The first path promises nuclear independence (so important to president de Gaulle) at a price. The enriched uranium route has a cost advantage. The second path promises more economic power, but also at a price. The French would have to agree to U.S. licensing conditions. This year France will consume an equivalent of 650 million tons of coal for her power needs. In 1980 she will need 1130 million tons. By that time the part that nuclear power supplies to total power needs (now 2%) will be at least 10%. Three process possibilities are open to the French government: natural uranium, enriched uranium, or a natural uranium-heavy water process. The advantage in choosing the natural uranium process lies with the large and easily available uranium resources in France and French speaking Africa. But E.D.F. 3, the big power plant in Chinon which is based on natural uranium, has experienced a year's shutdown due to a turboalternator malfunction, and is still not fully operative. The American enriched uranium process is cheaper, easier to operate, and safer. France is making some enriched uranium in Pierrelatte, but it is only used for atomic tests. The third process possibility, which is used by Canada and Sweden, is the natural uranium-heavy water process. The cost of electricity in France for each of the processes would be 0.58 cent per kwh. for the natural uranium-heavy water process, up to 0.69 cent per kwh. for the present French process, and 0.62 cent per kwh. for the enriched uranium process. The price of electricity is of growing concern, if France is to remain competitive in the Common Market. Pechiney has already decided to build a big aluminum plant in Cologne, West Germany, where electricity is 20% cheaper than in France. Which way will France choose? If her recent decision to build a new natural uranium plant in Alsace, and at the same time launch a venture in enriched uranium with Belgium is any guide, it appears that president de Gaulle may decide to wait and see.
