THE C H E M I C A L W O R L D THIS WEEK
Sir Christopher Hintori (left), deputy controller of atomic energy, and C. J. Smithells, president of the Institute of Metals, chatting informally at the Royal Institution prior to the May lecture delivered by Sir Christopher the latter part of last month C&EN REPORTS: Institute of Metals
Atomic Energy Plants Need Improved Fabrication Techniques Metallurgical industry is neglecting problems of handling haiides LONDON.—Better methods of metal fabrication and a wider range of materials resistant to halide attack are urgently needed by today's chemical plant designers. One of Britain's top chemical engineers, Sir Christopher Hinton, emphasized this in the 43rd May Lecture, which h e delivered here on March 23 before the annual general meeting of the Institute of Metals. Sir Christopher is Deputy Controller of Atomic Energy (Production), Ministry of Supply. In his plea for better fabrication techniques, the lecturer cited austenitic steel as an example. Although this type of steel plate gives excellent resistance to corrosion under oxidizing conditions, the speaker declared that today it is not possible to have the same confidence in the weld as in the parent metal. Under severe conditions, the British are using an 18-13-1 stainless steel plate, welded with an 18-8-1 stainless electrode. Sir Christopher stated that this technique avoided hair cracks but did not eliminate the ferrite structure in the weld. In atomic energy, many vessels become radioactive to such an extent that they cannot b e approached for future repair. Sir Christopher explained that since one minor weld failure might put an entire unit permanently out of commission necessitated utmost care in fabrication. Joints must be x-rayed, but even this procedure had to b e specially developed for controlling acceptability in chemical use, he said. Halide Attack. Turning to the problem of materials of construction for halogen service, the lecturer pointed out that mild 1532
steels can be used for dry haiides at moderate temperatures, but when the hydroxyl ion is present, today's materials present definite limitations. Glass and rubber lining can be used for hydrochloric acid, but rubber cannot be used for bromine and neither rubber nor glass can be used for fluorine, Sir Christopher explained. The chemical industry has not taken its responsibility seriously in regard to the many facets of fluorine chemistry, he declared. Predicting considerable developments in this field, he lamented the fact that today the only suitable material for handling fluorine is graphite. This question of halide attack, particularly fluorine handling, is one of the important considerations in building the chemical plants associated with production of atomic energy, said Sir Christopher. At the present time, more than half of the effort lies in the associated chemical plants, but the lecturer opined that as time progresses the situation will be reversed and more effort will be expended in connection with the reactors themselves. Reactor . Requirements. Although aluminum and magnesium have been used in the British thermal reactors to date* the lecturer pointed out that neither is an ideal material if the reactor is used for industrial power. A low neutron absorption tendency, high purity (freedom from nonmetallic inclusions), and a relatively high melting point are required. Beryllium and zirconium are being investigated for this application, he said. C H E M I C A L
In a fast reactor, where the fuel is rich in fissile atoms, a moderator is not used to slow the neutrons. Large amounts of heat must be taken away from a small area. Liquid metals such as mercury, sodium, and lead are used as coolants. All these conditions lead to rigid requirements for materials of construction, and Sir Christopher listed these as: simple structure with resistance to corrosion from fuel or coolant, high heat conductivity, and high creep strength. Stainless Steel Habit. Issuing a plea for moderation in specifying materials of construction, the speaker pointed out that stainless steels are used in many places where corrosive conditions do not require that high a standard. The chemical engineer should be broken of the stainless steel habit, he declared. His case in point was in the pharmaceutical industry, where great amounts of stainless steel are used just to maintain cleanliness. Plastics are already replacing metads in some cases in the food industry and the metal industry must b e alert to provide satisfactory competition, he said. In his introductory remarks, Sir Christopher called attention to a new era in chemical industry which appeared to start in about 1925. Prior to this time, chemical plant designers made very few demands on the metallurgists—they used metals which had been developed for other industries. However, after 1925 several factors seemed to prompt the chemical engineer to demand specific materials for specific jobs. The formation of large chemical combines and the rapidly developing American petroleum industry, with its high pressure and high temperature techniques, did much to bring about this change of attitude, he said. H e predicted that the chemical engineers will continue to make demands of the metallurgical industry for specific materials for specific applications.
INDUSTRY Catalytic Reformer to Be Built by Magnolia T h e contract to build a multi-million dollar Thermofor catalytic reforming unit at Magnolia Petroleum Co.'s Beaumont, Tex., plant has been awarded to the Lurnmus Co. Construction will get under w a y with completion of final engineering, which is expected to require about three months. Initial operation of the unit likely will take place during the first half of 1954. Socony-Vacuum Co., with which Magnolia is affiliated, is building three such units, plus a catalyst manxifacturing plant at Paulsboro, N . J. Total cost of the four units will be $27 million. The other TCR units are at Torrance, Calif., and Augusta, Kan. T h e contractor will provide an exact scale model, one-fiftieth the size 'of the A N D
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