structed at their lab, the chemists will check the following significant items:
RESEARCH Breeders: What Kind? H o m o g e n e o u s o r heterogeneous types — n e w l y disc o v e r e d nitrogen-15 may be a factor
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PNTE QUESTION facing atomic furnace
designers: Will future breeders be homogeneous or heterogeneous? Pretty much in balance until now, the scales may be tipped in favor of the homogeneous breeder b y recent discovery of an isotope separation method to produce 95 +9c nitrogen-15. The process was developed by T . L. Taylor and William Spindei of Columbia University. Significant part of the Columbia chemists' development: For a thorium type homogeneous breeder, reactor people would like to use something like thorium nitrate in the blanket, but this chemical made with ordinary nitrogen would absorb too many neutrons. For this reason it has never been used. Instead, atomic workers turned to a thorium oxide slurry, and to date this has appeared promising. However, with nitrogen-15 available, thorium nitrate might b e practical. Basis for this is that N 1 5 absorbs few neutrons because of its low absorption cross section. This means the new isotope opens the road to more serious study of the homogeneous reactor. But, it should be added, other problems could be created—such as corrosion and decomposition. Another problem is that N 1 5 is present only to t h e extent of 3.7 parts per thousand in ordinary nitrogen. Hence, extraction and concentration are expensive. To date, best commercial efforts got 6 0 % N 1 5 , but at a cost of around $175,000 per pound. In part, this high cost w a s due to limited production. Manufactured in larger quantities, costs would b e lower, b u t thus far n o attempt has been made in this direction. Taylor and Spindel's method cuts cost to around $450 to $500 per pound, based on a 50-pound-per-day plant. High hopes are held that closer studies —proeesswise a n d economically—may result in even lower cost estimates. Particularly important will be the byproduct sulfuric acid use, since it is "normal" to h a v e a captive use or certain market within 100 miles of the production plant. • What's Been Done. T h e Columbia chemists' process is based upon the 5480
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exchanges of nitrogen-15 for nitrogen14 using a nitric oxide—nitric acid system. Briefly, the method uses a series of chemical exchange columns in which nitric oxide gas turns over its nitrogen15 to nitric acid. This is repeated with a 5% enrichment of t h e isotope for each stage, until the nitric acid is rich enough to be drawn off. At present, two columns, each 18 feet high, provide sufficient stages to produce the 95-r-7c nitrogen-15.
• Single stage enrichment f a c t o r present estimates are based on value of 1.049, b u t it m a y be 1.06. T h e second figure would improve the economic picture. • Product refluxer—reaction between nitric acid a n d sulfur dioxide occurs rapidly and in a very short zone ( i n the pilot plant, 10 to 15 m m . in a 45-mm. reflux reactor). This means the product refluxer length may be c u t in half. On t h e other hand, a specially designed heat exchanger may b e required to take care of excels heat generated. • Process design improvement is needed to prevent loss of N 15 —a small loss is appreciable from the dollars a n d cents viewpoint. • By-product sulfuric acid—for best economics, production should b e integrated with manufacture and/or use of sulfuric acid. Present estimates value
Columbia chemists Spindei (left) and Taylor with their nitrogen-15 "pilot plant" Sulfur dioxide is used to decompose nitric acid to form nitric oxide. T h e S 0 2 used finally ends u p as 5 0 % sulfuric acid, a useful by-product. A drawback here is that production of 1 pound per day of N 1 5 results in making 37 tons of sulfuric. Commercial a p plication of N 1 5 for reactors would require around 50 pounds per day, hence about 1850 tons of sulfuric (50%) would end u p as a by-product. • What's to Be Done. First thing on the books, according to Taylor and Spindei, is to recheck a n d revise t h e economic appraisal. This also includes improving the process for possible commercial use. Using a pilot plant con-
the product, now 58° to 60° Be., at $18.60 per ton. Closer studies will b e made to improve concentration of t h e sulfuric. • Use of sulfur rather than sulfur dioxide as a r a w material—this should b e more attractive from t h e commercial viewpoint. • Optimum in flow rates and exchange rates. • Operation of columns at higher pressures—this should improve flow rates, and allow use of higher initial concentration of nitric acid. • Use of nitrogen dioxide-nitric oxide (liquid-gas) exchange system—
Homogeneous Reactor; H o w One Works In the thorium type breeder reactor, a core of uranium-233 is surrounded by a liquid thorium blanket. As U 2 3 3 atoms fission in the core, they shoot neutrons into thorium-232 contained in the blanket—converting them to fissionable U 2 3 3 . T h e n e w U 2 3 3 then is continuously removed by processing t h e blanket. Most of it goes back into the reactor to keep the "fire" going, some atoms are lost, and any surplus can b e put into the core of a n e w reactor to get it started. Energy from the atomic furnace comes from the heat generated during the fission.
little different way. But, if gamma radiciliuu can be put to work effectively and economically, adds Murphree, it could eliminate—or at least minimize— the need for costly external heating equipment, and it might make available greater quantities of valuable oil products such as gasoline and heating oil—and at reduced production costs. Even if the results of current lab tests were promising it would be several years before any commercial application would b e undertaken. Exhaustive evaluation of lab experiments and small pilot plant operations would have to b e followed by more extensive studies in larger pilot plants—something of the order of 10O barrels per day capacity.
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Tobacco Research time schedules prevented this work during original development, b u t preliminary studies have been encouraging. Besides these lab studies, there are the factors of material, labor, and plant investment costs. As far as Taylor and Spindel see it, there are a lot of "bugs" and a lot of work. In the meantime they will look to their exchange columns and keep going. //I
Hot" Gasoline Esso Research puts r a d i o activity to w o r k ; hopes g a m m a rays will improve or r e p l a c e present processes
HAT with all the talk about atomic energy and how it may replace sources of fuel in the future, Esso Research and Development Co. has come up with a new twist. W h y not use radioactivity to make better and more economical petroleum products now? Pursuing this policy, Esso started a pilot plant at the company's research center in Linden, N . J., last summer (C&EN July 11, page 2 8 9 0 ) . Now, the first information obtained has begun to drift out. For example, Esso researchers have been able to make small quantities of gasoline by exposing c r u d e oil to intense gamma radiation. Also, the gasoline was made in greater yield than that obtained from conventional practices. &• Proceed with Caution. E. V. Murphree, president of Esso Research, says that it is still too early to predict w h a t the results might be, but, there are indications that radiation may be a means to produce additives that will make an improved lubricating oil to give better automobile performance. Also, radiation activates certain reactions in refinery processes, makes them go faster, and makes them go in a
The Tobacco Industry Research Committee has made 19 new grants and renewed nine previous grants, to bring its total for t h e year to $838,000. The new grants total more than $355,000. Among trie new grants are: E . M. Butt, University of Southern California, for a study of trace metal storage of pulmonary and live tissue by spectrographic and chemical methods. Cecilie Leuchtenberger, Western Reserve University, for quantitative analysis of nucleoproteins in tissues from animals subjected to tobacco smoke by mierospectrophotometry and interference microscopy correlated with cytological and histological studies. Sam Sorof, Institute for Cancer Research and Lankenau Hospital Research Institute, for chemical and physical studies on the tissue proteins involved in chemical carcinogenesis. Simon EL Wender, University of Oklahoma, for qualitative and quantitative study of the individual polyphenol content of cigarette tobacco and of the smoke and "tars" resulting from cigarette smoking; also for a study of the fate of these compounds in the animal respiratory system.
• New classes of liquid scintillation phosphors have been studied at University of Chicago (Science, Dec. 9 ) . About 40 "whiteners" used in laundry detergents and some related compounds were studied. Two showed special promise: 7-diethylamino-4methylcoumarin and 2 (p-dimethylaminophenyl)benzthiazole. James R. Arnold (now at Princeton) found that none of t h e compounds tested was superior to the best phosphors now available; however, since they represent entirely new classes of compounds, they may b e of interest as a starting
S&S Filtration Chart This desk-sized chart shows a t a glance w h i c h filter p a p e r t o use f o r a g i v e n a n a l y s i s . Gives r e l a t i v e r e t e n t i o n v a l u e s of S&S Analytical Filter Papers and other brands.
S&S Filter Paper Sampler
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*"Bac-T-Flex" i s a trademark
Waif ~te imfm ww! • C a r l Schleicher & Sehuell Co.
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Dept. C-12, Keene, N e w Hampshire
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S e n d y o u r f r e e S&S
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i~~] Membrane Filter Folder D P*' rer Paper Sampler • Filtration Chart
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