Equations based on kinetic theory relate the contamination of refractory metals in vacuum to the appropriate variables. Several examples are given for which the allowable system pressures are calculated. The examples illustrate the effect of varying several parameters. The importance of the sticking factor for active gases on hot refractory metals and its effect on the system design are discussed. The data for estimating the sticking factor for O/sub 2/ on Nb are given, along with some estimated values. Experimental data on the composition and rates of outgassing of ultrahigh-vacuum systems and their importance in system design are discussed. Several methods of reducing contamination rates and the relative ease and effectiveness of these methods are presented. It was concluded that tests of 1000 hr or longer will probably require system pressures of between 10/sup -9/ and 10/sup -6/ torr, the particular pressure depending upon the residual gas composition, test duration, allowable contamination level, and the other variables discussed. Since the most important source of contamination in a properly designed ultrahigh-vacuum system is the outgassing process, bakeable systems should be designed to operate with walls as cool as practical, and to have a minimum of surface area and outgassing materials inside. …

Molten fluoride salts, because of their radiation stability and ability to contain both Th and U, offer important advantages as high-temperature fuel solutions for nuclear reactors and as media suitable for nuclear fuel processing. Both applications have stimulated experimental and theoretical studies of the corrosion processes by which molten salt mixtures attack potential reactor materials. Corrosion experiments with fluoride salts which were conducted in support of the Molten-Salt Reactor E xperiment and analytical methods employed to interpret corrosion and masstransfer behavior in this reactor system are discussed. The products of corrosion of metals by fluoride melts are soluble in the molten salt; accordingly passivation is precluded and corrosion depends directly on the thermodynamic driving force of the corrosion reactions. Compatibility of the container metal and molten salt, therefore, demands the selection of salt constituents which are not appreciably reduced by useful structural alloys and the development of container materials whose components are in near thermodynamic equilibrium with the salt medium. Utilizing information gained in corrosion testing of commercial alloys and in fundamental interpretations of the corrosion process, an alloy development program was conducted to provide a high temperature container material that combined corrosion resistance with useful mechanical properties. The program …

Progress is reported on thermonuclear research. Separate abstracts were prepared for 8 of the 10 sections. Design and engineering service reports and notes are given in the remaining sections. (M.C.G.)

The complete electrostatic and spin-orbit matrices of the f/sup 5/ electron configuration were calculated and are presented tabularly. (auth)

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S>The compatibility of type 304L stainless steel in intimate contact with graphite is being studied as a function of temperature and contact pressure. This study is an outgrowth of materials compatibility problems in present and advanced gas-cooled reactors, where structural members in direct contact with graphite provide the possibility of both carburization and self-welding. Initial studies were concerned with surface reactions in the absence of gaseous contaminants under a vacuum of 10/sup -6/ mm Hg at 540 to 705 deg C. Stainless steel specimens are pretreated to provide three surface conditions: H/sub 2/- fired, preoxidized, and Cu-plated. Surface contact pressures ranged from 0 to 10,000 psi. Test results are presented which establish the lower temperature limit for significant diffusion between graphite and stainless steel at approximately 60O deg C. Above this temperature, diffusion between untreated or H2-fired stainless steel surfaces was found to effect complete bonding of the two materials at contact pressures as low as 500 psi. Bonding was effectively prevented by the presence of either an oxide film or a Cu plate at temperatures up to 700 deg C. Where bonding occurred, diffusion rates measured for C in stainless steel were comparable with those reported for stainless steel …

A description of the EBR-II shield and the methods employed in arriving at the final design are presented. The major shield design problems for that reactor are enumerated and discussed. (auth)

Operation of the Lampre I during the report period is described and data on the operating history of this reactor are summarized. Other work is reported on core calculations, fuel and container development, and compatibility of Pu-Co- Ce alloys with Ta. Studies of the physical properties of Pu alloys with C, ln, Si, and rare earths are described. Data on the room temperature densities in the Pu-Ce-Co alloy system are presented. Solvent extraction studies concerning separation of Pu are included along with results of electrorefining of irradiated Pu fuels. The developmental status of the core test facility is reported. (J.R.D.)

Six procedures, in stepwise form, that can be used for the determination of plutonium in several forms by controlled-potential coulometric titration are presented. (auth)

A general description of the facilities used to house a small Cockcroft- Walton generator is presented. Preliminary irformation and data are given as to the operational performance of the generator, the radiation safety controls involved, and the expected use of the device, In addition, an automatic-manual device for control of tritium target usage is described. (auth)

Chemically purifled Zr/sup 95/ was used in determining selfdiffusion coefficients in the body-centered cubic phase of iodide zirconium over the temperature range of 900 to 1750 deg C. In order to minimize effects of build-in of the daughter isotope Nb/sup 95/, all heat treatments were completed within 48 hr after the purification. The temperature dependence of the diffusion coefflcients could not be described by the usual Arrhenius-type equation. Instead, apparent values of the frequency factor D/sub o/ and the activation energy Q varied from 4.8 x 10/sup -6/ to 2.5 x 10/sup -2/ cm/sup 2//sec and 20700 to 46900 cal/mole, respectively, between the lower and upper extremities of the temperature range. Empirical treatment of the data indicated that Q is a linear function of temperature and that D/sub o/ varies with a power of the temperature. The data may be described in terms of the alpha to BETA transition temperature of 1136 deg K and the absolute temperature of the heat treatments by the following equation: D = 3 x 10/sup -6/ (T/1136)/sup 15.6/ exp (--19600 + 31(T -1136)/RT) cm/sup 2//sec. (auth)

The climb rate of prismatic dislocations in quenched Al-5% Mg Alloy was studied by bulk annealing and also by high-temperature electron microscopy of thin foils, In bulk and thin-foil specimens, loops and helices were always observed to grow. The activation energy was determined to be 0,95 plus or minus 0.05 ev. The results can be interpreted on the basis of a binding energy between vacancies and magnesium atoms which can be x0.1 to 0.4 ev, depending on their geometrical configuration. (auth)

The effects of uncertainties of nuclear data on the calculation of integral quantities for some fast breeder systems were evaluated. The integral quantities chosen were reactivity, initial breeding ratio, and initial internal breeding ratio. The fuels chosen were Pu/sup 239/-U/sup 238/, both as metal and oxide, and U/sup 233/-Th as oxide. The importance of propagation of errors on the uncertainty in reactivity was determined. Results indicated that because of inaccuracies in the values of nuclear parameters as known within the present state of the art'' the deviations of the calculated reactivities should be about, and possib1y larger than, 2% DELTA k/k for all the medium and large systems considered. The deviation of the initial breading ratio is 3.5%, and for the initial internal breeding ratio it is about 5%. The consequent uncertainty in the calculated critical mass is of the order of 4%. (M.C.G.)

A study was made of the preparation of alpha, gamma, and neutron sources using the long-lived radioisotope of americium, Am/sup 241/. Americium-241 is an artificiallyproduced radioelement which has a half-life of 462 plus or minus 10 years and decays to Np/sup 237/ by alpha emission followed by low-energy gamma emission. The high specific activity of americium-241 (7.0 x 10/sup 9/ d/m/mg) combined with its reasonably long half-life makes it ideally sulted for the preparation of radioactive sources. The chemical and physical properties of Am/ sup 241/ and the physical manipulations involved in fabricating alpha, gamma, and neutron sources are generally described in this report. Uses for each type of source are discussed and data are presented to indicate the respective properties and usefulness of each source type. (auth)

Discrete quadrature weights and angles for use in discrete ordinate methods of solutions for thin cells were tabulated for a series of regional cell thicknesses of applicability. Parameters are given for 4, 8, 8, 10, and 12 angle approximations. The quadrature assignment was based upon a simplified integral transport solution to the spatial average of the angular distribution of uncollided flux, assuming flat sources. The quadrature assignments are designated TRIM, for thin-region integral method, and are most useful with thin cells having either or both regions very thin in mean-free-path units. The IBM- 704 Fortran program used to compute the parameters is described. (auth)

A critical comparison of measured and calculated central fission ratlos for 18 ZPR-III fast reactor assemblies was made with the object of examining the accuracy of computation of spectra and of the fission cross sections used. This comparison uses fission ratios measured with Kirn absolute fission chambers and computed with ANL cross section Set 635. The Kirn chambers and experimental technique are described. It is shown that ratios measured with threshold detectors must be corrected for the effects of inelastic scattering in the chamber walls. Possible sources of error in the experimental technique are discussed, and experimental evidence for the validity of the method is presented. The derivation of ANL Set 635 is described. It is shown that Set 635 is a modification of the Yiftah, Okrent, and Moldauer ANL Set 135 and that the central spectra and fission ratios calculated with the two sets are generally similar. The U/sup 234/and U/sup 236/ fission cross sections are not given in Sets 135 and 835; these were taken from ANL Set 179. The measured and calculated fission ratios obtained with U/sup 233/, U/sup 234/, U/sup 235/, U/sup 236/, Pu/sup 239/ , and Pu/sup 240/ were compared, both to search for trends …

Magnetic moment measurements are made on holmium single crystals (hcp) from 1.3 to 300 deg K in magnetic fields from 250 to 18,000 Oe, with the field applied along the c axis, the a axis, and a (1010) direction. The STA1010! direction is the direction of easy magnetization with an extrapolated effective moment per atom at saturation of 10.34 Bohr magnetons. Basal plane measurements show antiferromagnetism below the Neel temperature of 132 deg K with basal plane anisotropy occurring below 80 deg K. Below the Neel point, an anomalous type of transition to ferromagnetic behavior upon application of sufficient field is observed. Magnetization curves for the c axis are linear down to 60 deg K, while measurements below 20 deg K show an initial magnetization of approximately 1.7 Bohr magnetons followed by nearly linear magnetization curves. Electrical resistivity measurements are made from 4.2 to 300 deg K. For the a axis, the resistivity changes slope slightly at 20 deg K. A larger change in slope occurs at the Neel temperature of 132 deg K. For the c axis, the resistivity changes slope slightly at 20 deg K, reaches a peak at 120 deg K, goes through a minimum at 132 …

A total of 25 sections is incorporated in the report. Separate abstracts were prepared for 22 of the sections. Those sections for which no abstracts were prepared are concerned with Th fuel cycle development, assistance programs, and publications. (J.R.D.)

Theoretical investigation on the nature of ion exchange of acidified uranyl sulfate solutions with Dowex 21K, a strong base ion exchange resin.

A review is given of the present state of knowledge concerning the condensed phases of He{sup 3}. Attention is confined to the pure substance, and emphasis is placed upon the theoretical understanding of the material.

This report covers the following titles: (1) Synthesis of compounds from {sup 14}CO{sub 2} by Chlorella in the dark following preillumination; (2) The effect of oxygen on formation of glycolic acid and other products during photosynthesis by Chlorella; (3) Phosphatase action on phosphoglycolic, 3-phosphoglyceric, and phosphoenolpyruvic acids in spinach chloroplast fragments in the presence and absence of high concentrations of methanol; (4) Absorption spectra of scattering samples. I. An evaluation of three different spectrophotometric techniques using Chlorella; (5) Absorption spectra of scattering samples. II. Scattered transmission spectra of leaves, chloroplasts, and quantasomes of spinach; (6) The effect of sonication of spinach chloroplasts on photosynthetic phosphorylation; (7) Concerning the occurrence of {alpha},{alpha}-tocopherol and {alpha}-tocopherylquinone in chloroplasts and quantasomes; (8) Effects of ultraviolet and gamma radiation of thymine in frozen aqueous solution and in the solid state; and (9) A rapid method for the identification of small quantities of lipid-soluble vitamins and quinones in biological material.

By equating net radiation to space to I/sup 2/R heating in the SNAP-2 instrument compartments, and neglecting internal radiation between compartments, the panel surface equilibrium temperatures were computed for hot and cold temperature extremes. These extremes are defined by: (1) cold - pre-start phase in the shade, (2) hot - full power phase facing the sun. The results of the heat balances for hottest and coldest cases are presented graphically. These figures relate the equilibrium surface temperatures to the I/sup 2/R heat load dissipated by the panel surface for hot and cold orbits before and after startup. Included as parameters are effective panel area (dependent on Agena-interface design details) and the ..cap alpha../epsilon ratio for the surface coating. If ..cap alpha../epsilon = .3/.9 and A = 1 ft/sup 2/, the extremes of temperatures suffered are from -191/sup 0/F to +212/sup 0/F. This study shows that the normal R/C surface coating (..cap alpha../epsilon = .3/.9) is acceptable regarding allowable maximum surface temperatures, if the effective panel area is not less than 1 ft/sup 2/. It also indicates that further work is warranted regarding internal radiative distribution of heat in order to limit the lowest temperatures to -65/sup 0/F.

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Abstract: "The leakage neutron spectrum of a U²³³ spherical critical assembly (Jezebel) has been measured using nuclear emulsions as radiator and detector. The spectrum obtained is compared with similar measurements on the U-235 and Pu-239 analogues of Jezebel U²³³; it is found to agree closely with that of the Pu-239 assembly and to be harder than that of the U-235 assembly. All three spectra are compared with theoretical spectra obtained from a numerical approximation to the neutron transport equation."