Progress report of the Oak Ridge National Laboratory Biology Division providing updates on various projects, experiments, and other work. This report includes a summary of scholarly output from the division and departmental activities in cytology and genetics, mammalian genetics and development, microbial protection and recovery, mammalian recovery, pathology and physiology, general physiology, biochemistry, enzymology and photosynthesis, microbiology, plant biochemistry, and biophysics.

This report is the result of a study to develop heat-resistant fin materials possessing a high thermal conductivity for air radiators. Since an economical and commercially feasible product was desired, the investigation was restricted primarily to a study of electroplated copper, clad copper, and copper alloys. Sheet material 0.008 to 0.010 in. thick was evaluated for fabricability and for metallurgical stability and thermal conductivity at 1500°F. From the results of the rests it was concluded that: (1) electroplates were unsatisfactory; (2) clad-copper fins possessing a thermal conductivity of 50% of that of copper are commercially feasible; (3) copper-aluminum alloys possessing a thermal conductivity approaching that of copper at 1500°F are possible. Service tests of clad copper and the copper-aluminum alloys indicate that the choice of materials will be dictated by the requirements of the radiator, since each presents some unique problems.

Progress report of the Oak Ridge National Laboratory Analytical Chemistry Division providing updates on various projects, experiments, and other work in ionic analyses, analytical instrumentation, radiochemical analyses, activation analyses, spectrochemical analyses, inorganic preparations, optical and electron microscopy.

Progress report of the Oak Ridge National Laboratory Metallurgy Division providing updates on various projects, experiments, and other work. This report includes a summary of nondestructive testing, physical chemistry of corrosion, fundamental physico-metallurgical research, HRP metallurgy, process metallurgy, metallurgical materials and processing, metallography, and ceramics research.

Several potential hazards that have been recognized and anticipated in the design and fabrication of the pressure vessel in the Homogeneous Reactor Test are discussed. These hazards results from the high operating pressure and temperature of the reactor, the exposure of the reactor vessel material to potential embrittlement and other affects of fast-neutron irradiation, and the need for containment of corrosive flowing liquids. The steps taken in recognition of these hazards are also discussed. The applicability of present codes to the reactor vessel fabrication is considered. Additional fields are suggested where recommended practices developed by code writing bodies could assist in development-type reactor design and fabrication.

Progress report of the Oak Ridge National Laboratory Aircraft Nuclear Propulsion Project providing updates on various projects, experiments, and other work. This report includes summaries of project activities in: aircraft reactor test design, ART physics, ART instruments and controls, component development and testing, procurement and construction, ART, ETU, and in-pile loop operations, phase equilibrium studies, chemical reactions in molten salts, physical properties of molten materials, production of fuels, compatibility of materials at high temperatures, chemistry, analytical chemistry, metallurgy, dynamic corrosion studies, general corrosion studies, fabrication research, welding and brazing investigations, mechanical properties studies, ceramic research, nondestructive testing studies, heat transfer and physical properties, radiation damage, fuel recovery and reprocessing, critical experiments.

In order that fairly accurate thermal stress calculations can be made on the ART, it is necessary to have a reasonable picture of the temperature distribution in the reactor. To get the temperature distributions, and to determine cooling requirements in various parts of the reactor, one must know the heat deposition rates due to alpha particles, beta rays, gamma rays, and neutrons in all parts of the reactor. The present report contains only the basic physical data necessary to determine the heat deposition rates due to gamma rays. Neutron fluxes in the core and reflector regions of the ART are to be obtained from two-dimensional multigroup calculations (performed by the Curtiss-Wright Corporation). These fluxes, in conjunction with the neutron absorption cross sections, determine the neutron capture and inelastic scattering rates in the core and in the reflector. The data in this report permit the calculation of the number of gamma rays originating at various energies at every point in the core and reflector.

This report presents a summary of certain physical properties that have been determined experimentally on the fluoride mixture that have been formulated at ORNL (Rers. 1, 2). These properties include the density, enthalpy, heat capacity, heat of fusion, thermal conductivity, viscosity, Prandtl number, electrical conductivity and surface tension. In addition to the experimental data, values have been predicted for the heat capacity and density of the other mixtures from the correlations of these properties. Estimates of the viscosity have also been made for a number of the mixtures on which no experimental data were available.

The Spectroscopy Research Laboratory is concerned with research and development in the fields of nuclear magnetic resonance, microwaves, infrared and optical spectroscopy, spectrochemistry, and x rays. Research is directed toward fruitful methods of isotope analysis; new element and compound analytical methods having application to immediate Laboratory or long-range commission needs; and fundamental research on isotopes, elements, and compounds. The work is reported on a project basis to give a more complete picture of the purpose, activity, and status of each program. More detailed information on reported or inactive projects may be obtained from the previous semiannual report.

The successful completion of a program of experiments, including the Aircraft Reactor Experiment (ARE), has demonstrated the high probability of producing militarily useful aircraft nuclear power plants employing reflector-moderated circulating-fuel reactors. Consequently, and accelerated program culminating in operation of the Aircraft Reactor Test (ART) is under way. In order to adhere to the compressed schedule of the accelerated program, it is essential that the Atomic Energy Commission approve the 7500 Area in Oak Ridge as the test site by February15, 1955. This report summarizes the hazards associated with operating the contained 60-Mv reactor of the ART at the proposed Oak Ridge test site.

From July through December, a total of 1750 hr of computer time was used by programmers in "debugging" and in running problems. With the acquisition of a second operator, the evening shift was initiated. A night-shift operator is presently being trained, and third-shifts operations will probably begin after completion of the magnetic-tape memory. / Engineering time is regularly scheduled for 4 hr each morning and 1/2 hr late in the afternoon. An electronic technician is on duty during evening-shift operations. / Installations of the magnetic-tape memory units is complete, and the units are expected to go into operation in the near future. Work is continuing on the new input-output system.

The reactor equipment cell is expected to be completed by February 15. While filled with water, the tank was inspected for leaks, and the few leaks found will have been repaired by February 15. All orders for construction materials placed prior to this quarter have been received. New requisitions issued during the quarter total $16,000. Work orders were issued, and fabrication of all low-pressure-system components was begun in the ORNL shops. The thermal shield around the reactor vessel was specified as a 2-ft-thick cylindrical concrete wall. With this shield, the fast-neutron flux in the equipment area will be reduced to 7 x 109 neutrons/cm2/sec, the slow flux to 4 x 107 neutrons/cm2/sec, and the gamma intensity to less than 105 r/hr. The possible blast effects from a rupture of the pressure vessel were studied and are judged to be sufficient to justify the inclusion of a 1.5. to 2-in.-thick blast shield around the pressure vessel. The blast shield eliminates the danger of damaging the leak tight equipment-cell liner. Pressures in the reactor equipment cell, as a result of vessel failure, were calculated in order to arrive at a safe design pressure for the reactor equipment cell. For the case of …

Gram amounts of americium were separated quantitatively from kilogram quantities of lanthanum to yield an americium product approaching 90% purity. The remaining impurity was chiefly yttrium. Elution of americium from 25% loaded Dowex 50 resin column with 0.15 M citric acid— 0.10 M diammonium citrate — 0.3 M ammonium nitrate, pH 3.3 gave a product containing 99% of the americium with a La/Am ratio of 1/100 or less in one fourth of a column volume, in this case about 1 100-fold volume reduction. Approximately 9 g of americium was purified by this method. Elution with 12.8 M hydrochloric acid from a 20 to 30% loaded column gave 90% of the americium in two column volumes of product with a La/Am ratio of about 1/4. About 1 g of americium was purified by this method.

Chemical and engineering data were obtained for the feed digestion system and the extraction-scrub step of the Monex tributyl phosphate solvent-extraction process for recovering thorium and uranium from nitric acid-digested unclarified monasite sludge. Tests of the recommended conditions in a 2-in.-dia pulsed column demonstrated that thorium losses were approximately 1.2% and uranium losses, 1.5%. The flowsheet is workable but is not necessarily optimum.

In scouting tests, a number of metals used in nuclear reactor fuel elements were dissolved by 44.5-48.5-7.0 mole % ZrF4-KF-NaF fused salt at 675°C through which HF was being passed. These included type 304 stainless steel at 4 mils/hr; type 347Nb stainless steel at 7 mils/hr; thorium at 14 mils/hr; nonirradiated uranium at 17 mils/hr; zirconium at 22-35 mils/hr; titanium at 31 mils/hr; and Zircaloy-2 at 22-46 mils/hr. Only small amounts of volatile fission products formed when irradiated uranium was dissolved. Variables that appear to affect the dissolution rate are the composition of the fused fluoride, the fused fluoride temperature, the HF flow rate, the metallurgical characteristics of the material being dissolved, and the presence of other metals. The low dissolution rate of 0.001 mil/hr observed for nickel suggests that it may be suitable as a material of construction for reaction vessels.

The ORNL 86-in. cyclotron is being modified to provide for deflection of the proton beam. It is expected that operation will be resumed late in the spring. Nuclear physics work was limited, for the most part, to interpretation of previously collected data and to making preparations for utilizing the deflected beam. It was found that for certain isotopes the production rates could be almost doubled by operating at a slightly reduced energy and a much larger current. With the use of the ORNL 63-in. cyclotron, the absolute values of the electron capture and loss cross sections for 26-Mev nitrogen ions were obtained. The angular distribution of the cross sections for elastic scattering of nitrogen by nitrogen was measured at energies from 13 to 22 Mev. A double-focusing 90-deg magnet is being planned for use in identifying stable reaction products from nitrogen-induced reactions. The major components of the revised 44-in. test cyclotron were assembled and are being tested. Consideration is being given to the use of these components, along with a new 20,000-oersted magnet and a shielded cyclotron room, and if the tests are satisfactory the Laboratory will have available a machine which will accelerate N5+ ions to 81 Mev.

A satisfactory ion-exchange-polarographic method was developed for the determination of either chromium(VI) or total chromium in Homogeneous Reactor fuels. Total chromium is determined as chromium (VI) , i.e., chromate, and in the same way as is chromium(VI), after chromium in the lower valence states is oxidized to chromate by potassium permanganate. Chromate is separated from all interfering metal ions in the fuel by ion exchange on a Dowex 50 resin column. The Chromate in the effluent is determined polarographically in approximately 0.75 M sodium hydroxide solution as supporting electrolyte. A well polarographic wave is obtained for the chromium (VI) chromium (III) reduction at a half-wave potential of -0.85 volt vs. the S.C.E. The relative standard deviation of the data for 2 μg of chromium (VI) per ml was 2%; for 4 μg of total chromium per ml, it was 3%. An ion-exchange-polarographic method was developed also for the determination of chromium(III). Chromium (III) is separated from all interfering ions in the fuel by ion exchange on a Dowex 1 resin column. The chromium (III) in the effluent is determined polarographically in a 1M ammonia-1M ammonium chloride supporting electrolyte. The wave obtained at a half-wave potential of -1.42 volt vs. the …

Part I. Experimental Reactors: The effect of prompt-neutron lifetime upon reactor safety was investigated for the HRT. It was found that for a given pressure rise the allowable rate of reactivity addition was relatively insensitive to the average prompt-neutron lifetime, although the rate de creased somewhat with decreasing lifetime for the higher pressure rises. With only source neutrons present and the reactor initially subcritical, the allowable rate was practically independent of the initial value of k£. For a core-pressure rise of 400 psi, the corresponding rate of reactivity addition was about 0.8% per second; for a pressure rise of 4000 psi, the rate was 2.5 to 3.0% per second. Part II. Thorium Breeder Reactor: An economic study of one-region thorium breeder reactors was completed. Where possible, the process characteristics and cost factors were the same as those used previously in studies of two-region-type reactors. The mini mum-cost reactor is about 12 ft in diameter, operating with 260 g of thorium per liter on a chemical processing cycle of about 450 days. The ratio of U232 to U233 produced is approximately 2 x 10~4 VIM in the minimum-cost one-region system, compared with 4 x 10 5 in the two-region system. The …

Bench scale studies have been made of the recovery of uranium from acid leach liquors (and slurries) by solvent extracting with di (2-ethylhexyl) phosphoric acid in an organic diluent. Uranium may be stripped from the organic solvent by either alkaline or acidic reagents, the former having been studied in greater detail. On the basis of these tests, a recovery process may be considered which shows promise both from the standpoint of operation and chemical costs. Under proper conditions, vanadium can also be extracted by the di (2-ethylhexyl) phosphoric acid and stripping again may be accomplished with either acidic or alkaline reagents. Preliminary studies have been made of these possibilities. In addition to di (2-ethylhexyl) phosphoric acid, some other organophosphorus acids, have been cursorily examined in respect to their extraction and/or stripping performance.

The proposed ORNL Research Reactor is designed to serve as a general purpose research tool delivering a maximum thermal flux of 8x10^13 n/cm2-sec at the initial power level of five megawatts. Operation at power levels up to ten megawatts is proposed for such items as sufficient cooling capacity is available to handle the increased heat load. The reactor will use MTR-type fuel elements and beryllium reflector pieces in a 7 x 9 grid with moderation and cooling provided by forced circulation of demineralized water. The reactor tanks are submerged in a barytes concrete pool, filled with water, which serves as a biological shield. Experimental facilities include two 18" diameter "Engineering Test Facilities" and six 6" diameter beam holes. In addition, access to the core is available through the water of the pool. The result on the surrounding population of release to the atmosphere of a large fraction of the radioactive material in the core has been computed by two methods. It is shown that under certain conditions off-area personnel could be subjected to greater than the maximum permissible exposure. An analysis of the maximum hazard caused by the release of the entire contents of the core to the local watershed …

Nuclear physics research with 22-Mev protons in the 86-in. cyclotron included angular-distribution measurements of neutrons from (p,n) reactions in nine target elements; measurement of the angular distribution of fission fragments from proton-induced fission of U233, U225, U228, Th230, and Th232; measurement of alpha-particle angular distributions from (p,α) reactions a study of the neutron-deficient isotopes of terbium and completion of an extensive program of the measurement of activation cross sections. Two more targets for cyclotron production of isotopes were developed, and the production yields for 14 radioisotopes are summarized. A new record for continuous beam power on a production target, 36 kw for 5 hr, was achieved. The design of a beam-deflector system for the 86-in. cyclotron has been completed, and several of the components have been fabricated ; a shutdown for installation is scheduled for October 8. The deflected N+++ beam of the 63-in. cyclotron was used in a study of the gain and loss of electrons by nitrogen lens passing through thin foils, and the equilibrium charge distribution of lens as a function of energy was thus obtained. The excitation functions were measured for nitrogen-induced reactions on both nitrogen and oxygen. Assembly restrictions of the prepared 114-in. heavy-particle cyclotron …

Results of tracer studies suggest that, in tributyl phosphate extraction processes designed to recover and purify fissionable material, minimum ruthenium extraction should be obtained from feeds at least 2 M in nitric acid or at least 1 M acid-deficient. Ruthenium decontamination was decreased by preheating the feed and increased by pretreatment with reducing agents. A pretreatment using 0.06 M ferrous ion and 0.5 M urea with 1 hr simmering at 85°C should increase ruthenium decontamination about 10-fold in the 25 process. If other process considerations dictate the use of a low-acid feed, decontamination from ruthenium may be improved by using 3 M nitric acid as the scrubbing solution. Apparently, the scrubbing process is quite time-dependent; a solvent holdup time of about 15 min may be needed in the scrub section for maximum decontamination.

Calculated data and graphs describing the effects of continuous thermal-neutron irradiation of thorium, the usual method of operations of homogeneous reactors, are presented.The buildup and decay of U^233, Pa^233, other heavy isotopes, and fission products are considered on the basis of best available cross-section and fission-yield data. The effects of the heavy isotopes and fission products on neutron economy are discussed.

Report describing the progress made in the Clinch River Study for the period May to October 1961. This report is based off of multiple reports of water sampling conducted across six stations in order to evaluate the safety and radioactive content of the Clinch River.