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when hardened, has little effect on gamma rays.75

The Bureau of Mines continued research on improving radiation control methods in uranium mines. The Pittsburgh Mining and Safety Research Center was performing experimental work on a Whitby aerosol analyzer to investigate attachment of radon daughters to natural Pittsburgh aerosol particles. A computer program for calculating radon daughter concentrations will be adapted to the Whitby system. At the Denver Mining Research Center, health and safety research was underway to develop quantitative data on the relation of radon emanations to natural uranium and to radium compounds in domestic uranium deposits. Included in the project were the design and assembly of radiometric instrumentation for radon quantitative data and assembly of a mobile field laboratory which will measure not only radiation but also such data as temperature and air pressure, velocity, and humidity in mines.

Jersey Nuclear Co., a subsidiary of Standard Oil Co. (New Jersey) and Avco Corp., announced development of a new uranium enrichment technique, based on laser technology. Details were not revealed, but it was claimed that results of research were favorable and that the process was lower cost than established processes. The technique is based on the principle that isotopes can absorb light at slightly different energy levels.

A test centrifuge was described by Comitato Nazionale Energia Nucleare (CNEN), Italy. The centrifuge is 3 feet long, 7 inches in diameter, and of fiberglass construction. It has a peripheral velocity of 1,150 to 1,970 feet per second.

A Zippe centrifuge, named after the consultant, is under development in the West Germany-United Kingdom-Netherlands tripartite plan. It is a light-weight bowl, supported on a pin-and-cup bottom and magnetic bearing on top. A high-frequency alternating current induction motor drives the bowl, which is contained in a small pressure vessel. Pilot tubes feed UF gas in and out of the bowl.76

Research continued on nuclear fuels and their performance. A PuO2-UO2 fuel was developed for the AEC's Fast Flux Test Facility (FFTF) at the Hanford project, Richland, Wash. The fuel was tested on a pilot line as part of the LMFBR develop

ment program. The fuel design consisted of 217 fuel pins, 7 feet long, each containing a column of mixed oxide fuel pellets. The pellets are 0.1945 inch ± 0.015 inch in diameter and 0.205 to 0.283 inch ± 0.020 inch in length. Other specifications requiring close control included oxygen-to-metal ratio, density, fissile content, impurity level, gas and moisture content, homogeneity, surface condition, grain size, and porosity. The PuO2 and UO2 are mixed, and an organic binder added, followed by prepressing, granulating, cold pressing, binder removal, and sintering. Pore-forming organic binders and presintering the blended oxides before binder addition were under evaluation. Care must be taken to prevent accumulation of a critical mass of fissile material in the pilot facility. A computerized data system was under development for monitoring the movement of all fissile material. Toxicity was controlled by performing all PuO2 processing steps inside gloveboxes.77

Gulf Energy and Environmental Systems reported discovery of a nuclear fuel having a lifespan several times that of previous fuels. It is a blend of U235 and erbium; the latter absorbs excess neutrons.78

Another new nuclear fuel, especially adapted to the HTGR, consisted of tiny microspheres of uranium, oxygen, carbon, and sulfur, derived from ion exchange resins. Tiny spheres of resin were exposed to uranyl nitrate; the resin absorbed uranium, forming uranium-loaded spheres, which were dried and then roasted in inert gas at about 1,800° C, forming the fuel particles. The particles were then coated with a dense layer of carbon to prevent escape of fission products into the gas inside the reactor.79

Uranium mononitride (UN) was considered attractive as a nuclear fuel in applications requiring high density of fissile atoms, high thermal conductivity, and high melting point. UN has high affinity for oxygen; therefore, the material must be synthesized, fabricated, and sintered under rig

75 Atomic Industrial Forum. Use of Plastic Sealant to Control Radon from Mill Tailings. Nuclear Industry, v. 19, No. 1, January 1972, pp. 29-31. 76 Chemical Engineering. Atoms-for-Peace Group Eyes Gas Centrifuges. V. 78, No. 25, Nov. 1, 1971, p. 38.

"Ceramic Age. Nuclear Power: FFTF Fuel Development Facility. V. 87, No. 6, June 1971, pp. 28-29. 18 Chemical Week. V. 109, No. 1, July 7, 1971, p. 27.

19 Am. Ceramic Soc. Bull. New Nuclear Fuel Developed. V. 50, No. 2, February 1971, p. 234.

idly controlled conditions to avoid oxidation.80

Studies were conducted on uranium and plutonium carbide fuels with tungsten additive up to 2 percent by weight, for swelling tests.81 Preparation methods included arc melting and casting of mixtures, float zone melting, and precipitation annealing of solid solutions. In earlier work on reducing fuel swelling, tungsten (1.5 to 3 percent by weight) was dispersed as fine particles in the uranium carbide fuel structure. During irradiation, the tungsten reduced swelling when uniformly dispersed, and the fine particles helped contain fission gases.82

Another report suggested that surface energy of UO2 is important to studies of diffusion-controlled processes involving fuel behavior, such as sintering and swelling caused by fission gases. This energy was calculated directly by measuring the interfacial equlibrium angles that developed between phases.83

UN also was selected as fuel material possibly for a small liquid-cooled fast reactor, maximum power 10 megawatts, for developing electric power in space exploration.84 The UN fuel has high thermal conductivity, high melting point, ease of handling and fabrication, and satisfactory nuclear properties. The objective of the study was the determination of chemical activity of uranium in UN as a function of pressure and phase composition, and phase equilibria. UN pellets were tested for spalling, cracking, and expansion.

Future nuclear power reactors were expected to be increasingly larger in capacity; advanced concepts; sited offshore, undersea, and underground; and nuclear complexes (nuplex), or nuclear-based energy centers. A 3,600-megawatt, $1 billion installation, a record capacity, was planned by Carolina Power and Light Co.85 Westinghouse Electric Corp. and Tenneco, Inc., announced a technical-economic feasibility study for an offshore, platform-mounted nuclear plant, within the 3-mile limit. Offshore siting would permit construction near load centers, would pose no land acquisition problems, and would lessen siting and thermal pollution controversy since heat would be absorbed by the sea. Another offshore plant of 1,100-megawatt capacity, proposed by Public Service Electric and Gas Co., Newark, N.J., would be mounted on steel or concrete floating barges in a breakwater area, with cables buried in the ocean

floor.86 Nuplexes were envisioned as optimizing possible mixes of capital-intensive industries. They could include desalination, fertilizers and chemicals, coal gasification (reducing gas for the blast furnace), methane reforming, ammonia production, and methanol production.87

A contract was awarded for the first application of a nuclear heat source for gas from coal. An HTGR will provide conversion temperatures of 1,600° C. The study was directed toward a plant producing 250 million cubic feet per day of pipelinequality gas and 400 megawatts of electricity generation.

AEC-sponsored and private research continued on advanced reactor concepts, mainly the fast breeder. The HTGR, an advanced converter using a U235-Th232-U233 fuel cycle, was further researched by GGA, ORNL, and Pacific Northwest Laboratory. It affords improved fuel utilization through a high conversion ratio and high thermal efficiency, reduced thermal discharge, long fuel lifetime, good safety characteristics, and minimum release of radioactive effiuents.

Further emphasis was placed on development of the LMFBR as plans for two demonstration plants, joint AEC-industry projects, were announced. The program is committed to development of a safe, reliable, and economic breeder reactor system. The transition from research to design, engineering, and testing on a commercial scale was underway. Construction continued on the 400-megawatt (thermal) FFTF at Richland, Wash., for irradiation testing of fuels and materials. The FFTF fuel is PuO2-UO2 pellets, 1/4-inch in diameter, in

so Tennery, V. J., T. G. Godfrey, and R. A. Potter. Sintering of UN as a Function of Temperature and N2 Pressure. Jour. Am. Ceramic Soc., v. 54, No. 7, July 1971, pp. 327-331.

81 Ervin, G., Jr. Uranium and Plutonium Carbides with Tungsten Additive. Am. Ceramic Soc. Bull., v. 50, No. 8, August 1971, pp. 659-661.

82 Ervin, G., Jr. Swelling Control in Uranium Carbide. Jour. Am. Ceramic Soc., v. 54, No. 1. January 1971, pp. 46-50.

83 Bratton, R. J., and C. W. Beck. Surface Energy of Uranium Dioxide. Jour. Am. Ceramic Soc., v. 54, No. 8, August 1971, pp. 379-381.

84 Hoenig, C. L. Phase Equilibria, Vapor Pressure, and Kinetic Studies in Uranium Nitrogen System. Jour. Am. Ceramic Soc., v. 54, No. 8, August 1971, pp. 391-398.

85 Engineering News Record. Around the World -Biggest Nuclear Plant. V. 186, No. 21, May 27, 1971, p. 13.

86 Chemical Engineering. V. 78, No. 11, May 17. 1971, p. 75.

87 Chemical and Engineering News. Nuplexes Seek Optimum Mix of Industries. V. 49, No. 13, Mar. 29, 1971, pp. 35-36.

stainless steel cladding. Testing will be in a controlled and instrumented environment, up to and including failure of materials. Emphasis was placed on supporting technology, complementing the LMFBR demonstration program, in work on fuels, materials, safety reactor physics, components, instrumentation, and fuel cycle.88 Research in the United Kingdom indicated that high neutron doses in the FBR can cause swelling of structural materials over periods of several years, posing a threat to the safety and economic viability of the FBR.89 Examination of irradiated stainless steel cladding from fuel pins by electron microscope showed that the steel contained a large number of small cavities, 100 atoms in diameter, resulting from swelling, or an increase in size. Irradiation damage was more pronounced where the neutron flux was the greatest. The fast neutrons interact with atoms of structural materials, displacing atoms from their equilibrium lattice.

Other breeder concepts under continuing study were the light water breeder reactor (LWBR), the gas-cooled fast breeder reactor (GCBR), and the molten salt breeder reactor (MSBR). At the AEC's Bettis Atomic Power Laboratory, Pittsburgh, Pa., where Westinghouse Electric Corp. is the operating contractor, work continued on a reactor core to demonstrate the potential for breeding in the LWR system, with the objective of improving LWR fuel utilization, which is only 1 to 2 percent of the energy potential of natural uranium. Breeding could possibly utilize up to 50 percent of the energy potential of thorium, which would be used in the seed-blanket concept. A demonstration plant, under construction at Shippingport, Pa., will assess the technical feasibility of this concept. The GCBR, closely related to the HTGR in that both are gas-cooled, was under development by GGA, ORNL, and 40 private company participants. A conceptual design was pleted; cost data and a demonstration plant program were under study. Research and development on the MSBR was centered at ORNL with private participation. This concept has potential for long life of fuels and materials at high temperatures, good neutron economy, and onsite fuel reprocessing if the complex technology for reprocessing and recovery can be developed. The fluid fuel necessitates no fabrication of fuel

com

elements. A six-company group was granted

a subcontract with ORNL for a conceptual design study on a 1,000-megawatt facility.90

In fuels reprocessing, AEC research was directed toward recovery of fuels from the advanced converters and breeders. The aqueous technology, used extensively in both Government and private reprocessing plants, was emphasized for LMFBR fuels.91 U and Pu were recovered by solvent extraction with hydroxylamine nitrate added.92 The scrap was dissolved, purified, and fed to the solvent extraction column. The nitrate reduced the U and Pu, which separated into two layers in the column. The Pu was removed from the top, and the U from the bottom.

At the General Electric plant, Morris, Ill., a combination aqueous-anhydrous process, called Aquaflour, was practiced. The process is complex, involving 28 steps, but reportedly has certain advantages.93 Ion exchange is used to partition Pu, Np, and U. Uranyl nitrate is converted to UF6, the compound required for enrichment.

The Purex solvent extraction process was considered capable of recovering 99.8 percent U from spent fuels with decontamination factors on the order of 107. An aqueous nitrate solution containing the U and Pu was contacted with an organic solution of tributyl phosphate (TBP), the extracting agent. The valuable nitrates, complexed with the TBP, flowed overhead; wastes were eliminated with the aqueous phase. Pu and U were separated in a subsequent extraction column. Several stages were necessary for purification.94

Other research and development on fuels reprocessing involved the preparation of the spent fuel rods. They are usually mechanically broken and then leached with nitric acid. Two innovations were an electrolytic dissolver for stainless steel cladding rods and a graphite burner for uraniumthorium fuels.

Quantities of gaseous, liquid, and solid radioactive wastes increased with new nu

88 Pages 99-104 of work cited in footnote 9. 89 Nelson, R. S. Filling the Voids in Fast Reactor Technology. New Scientist and Science Jour. V. 49, No. 3, Mar. 25, 1971, pp. 664 667. 90 Chemical and Engineering News. Molten Salt Breeder Reactor. V. 49, No. 31, Aug. 2, 1971, p. 27. 91 P.

139 of work cited in footnote 9. 92 Chemical Week. V. 108, No. 25, June 23, 1971, p. 35.

93 Chemical Week. Small Plant Tries to Make It Big in Nuclear Fuel. V. 109, No. 7, Aug. 18, 1971, pp. 91-98.

Chemical Engineering. Reprocessing Plants Rev-Up. V. 78, No. 19, Aug. 23, 1971, pp. 34-38.

clear power development. These waste materials require collection, transportation, treatment, and disposal by permanent burial or by storage for release to the environment under controlled conditions. The AEC estimated that a 1,000-megawatt BWR produces 1,500 to 5,000 cubic feet per year of waste materials, and a PWR produces 1,000 cubic feet per year, depending on method of plant operation and waste solidification system.95 These include high-level wastes (intense, penetrating radiation and high thermal power) and alpha wastes (principally solid materials, contaminated with Pu, of low thermal power and penetrability but extremely toxic), both of which must be contained outside the biosphere for thousands of years.

The objective of the AEC's waste management program was long-term storage of AEC-generated high-level and plutonium wastes, establishment of a Federal repository for wastes from commercial nuclear operations, and the reduction and control of radioactivity to the environment from waste management activity. AEC-generated wastes were stored at the Hanford facilities, Richland, Wash.; Savannah River, S.C.; and the NRTS, Idaho Falls, Idaho. At Hanford, in-tank concentration and solidification were practiced, reducing the volume and mobility of the wastes. A new heating system converted wastes to solid granules occupying 10 percent of the space required for the liquid form. At Savannah River, liquid wastes were converted to a highdensity slurry for deep underground storage. Storage in solid granular form was also practiced at the NRTS Waste Calcining Facility.

AEC and private research continued on waste solidification. Four methods were under consideration: fluid bed calciner, pot calcination, spray calcination, and phos. phate glass solidification. Technology has been developed with full-activity-level wastes and commercial-scale equipment. At West Valley, N.Y., Nuclear Fuel Services, Inc., disposes of high-level wastes in concrete-enclosed steel tanks, 600,000 gallon

capacity. General Electric planned waste conversion to solids by the fluid bed calciner process at its Morris, Ill., processing plant. In this method, the waste is concentrated in an evaporator, then fluid-bed calcined to solid form, and then placed in corrosion-resistant steel containers submerged in water-filled basins for cooling and shielding pending shipment to a Federal repository.

The AEC had tentatively selected an abandoned salt mine near Lyons, Kans., for permanent storage of high-level solids and transuranium radioactive wastes, although late in the year new data indicated a possible future problem with entry of water into the storage site. Disposal site selection in salt formations should meet the following criteria: 96 depths of 500 to 2,000 feet, thickness of at least 200 feet for adequate heat dissipation and isolation above and below storage chamber, horizontal extent of several tens of miles, tectonic stability, relative isolation from large population centers, access by rail and motor freight, social acceptance, and presence of an existing mine (to expedite construction and reduce costs).

The AEC was investigating deep, longterm storage of high-level wastes in crystalline bedrock, 1,500 to 2,000 feet deep, near its Savannah River Operations Office. Two drill cores were obtained in basalt, 4,500 feet deep, testing the feasibility of storage in deep underground openings near the AEC's Hanford operations, Richland, Wash.97 The U.S. Geological Survey conducted research to evaluate the effects of wastes injected into the ground on subsurface water supplies. Data were obtained on effects of these wastes on rock structures, rock stresses, hydraulic stresses, and chemical reactions.98

95 Pages 158-162 of work cited in footnote 9. 96 Blomeke, J. O., and W. C. McClain. A Salt Mine Repository for Radioactive Wastes. Nuclear News, v. 14, No. 4, April 1971, pp. 35-38.

Chemical and Engineering News. Radioactive Waste. V. 49, No. 32, Aug. 9, 1971, p. 81.

98 Chemical and Engineering News. Underground Waste Study. V. 49, No. 34, Aug. 23, 1971, p. 37.

Vanadium

By Harold A. Taylor, Jr.1

The domestic supply of vanadium was more than adequate to meet the domestic demand. Demand abroad was also weak. Domestic production was down somewhat from that in 1970. Exports of both ferrovanadium and oxide were only a fraction of those in 1970, whereas imports of ferrovanadium were higher although nowhere near the levels of 1969 and 1968.

Legislation and Government Programs. -The President imposed a 10-percent ad valorem surcharge on all dutiable imports up to the statutory limit from August 16 to December 20, 1971. This applied to all forms of vanadium except ore and concentrate. The simultaneously declared price controls posed no problems, because the adequate supply and shrinking demand for

vanadium in 1971 would have kept the prices down in any event.

The Government made no offerings or sales of the surplus vanadium in its stocks in 1971. On August 11, the President signed Public Law 92-112 authorizing the disposal, preferably by publicly advertised bid, of 1,200 short tons of vanadium contained in material held in the national stockpile.

As of December 31, 1971, the Government's inventory included 3,329 short tons of vanadium, all of which was in the national stockpile. Of the 3,329 tons, ferrovanadium comprised 1,200 tons, and vanadium pentoxide 2,129 tons.

1 Physical scientist, Division of Ferrous Metals.

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1 Measured by receipts of uranium and vanadium ores and concentrates at mills, plus vanadium recovered from ferrophosphorus derived from domestic phosphate rock.

DOMESTIC PRODUCTION

The Colorado Plateau uranium-vanadium ores were still the principal domestic source of vanadium, but not by a large margin. The amount of vanadium recovered from Arkansas vanadium ore increased, and the

amount of vanadium recovered from ferrophosphorus also increased. In addition, some of the mills processed vanadium residues, spent catalysts, and foreign vanadiferous slag. The recovered vanadium pent

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