Report documenting the progress of the Army Gas-Cooled Reactor Systems Program to develop a mobile nuclear power plant for military field operation.

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From summary: The design of a spectrometer with the requisite improvement in crystals facilitates X-ray tube fluorescence.

Quarterly report discussing activities of the Maritime Gas-Cooled Reactor (MGCR) Program and the progress of the Program in developing a nuclear-powered marine propulsion system utilizing a high-temperature, gas-cooled nuclear reactor, close-cycle gas-turbine power plant.

An investigation of the emission spectrum from radiation-daniaged xylene led to the conclusion that no gross corrections are needed for xylene when used as a scintillation solvent. Data are included from measurements of nonradioactive energy transfer in p-xylene and diphenyloxazole organic scintillation solutions. Measurements were made of the energy resolution of a twinscintillation fast neutron spectrometer. Accurate values of electron drift velocity in purified noble gases and nitrogen were obtained by measuring the transit time of photoelectrons across the gap of a parallel-plate condenser. Information concerning the transport collision cross section of low-energy electrons on noble gases was obtained from drift-velocity data. A method is discussed for the determination of traces of Freon-12 by positive ion emission techniques. Data are reported from late observations of the distribution of radium in the human body; the microscopic distribution of the dose in the skeleton arising from deposited calcium-45, strontium90, and radium-226 as measured autoradiographically; and determinations of individual alpha emitters in mixtures of alpha emitters. Data are tabulated from measurements of gross fission product radioactivity in air samples and in samples of soils collected from August through November 1959. The soil and air fall-out data are discussed. Measurements were made of the …

Construction of the NUMEC Plutonium Facility was essentially completed. Methods for the preparation of Pu, U, and Th oxides of high purity and the fabrication of these materials into fuel shapes is discussed. (For preceding period see NUMEC-P-10.) (W.L.H.)

Thermal stress testing was performed on two fuel plates, one cut from a brazed SM-1 dummy fuel element and the other from a TIG Welded SM-2 reference element. The test specimens were subjected to transverse temperature differences of up to 200 deg F, and distortion and strain at various locations were measured. The effect of the thermal stress was to increase the amplitude of original distortions. Adddtional distortions due to thermal stress were proportional to temperature differential and to ripple length. Tensile stresses in the side plate sections were measured as approximately 10,000 psi at maximum reactor temperature difference. Individual weld loadings in shear were measured as 38 lb per weld. Results of the tests were considered inconclusive because of unrepresentative initial plate distortion. (M.C.G.)

Abstracts were prepared on 26 of 28 papers presented at the Conference on the Physics of Breeding held at Argonne National Laboratory on October 19 to 21, 1959. (C.J.G.)

Chemical-Metalluaical Processing. A direct-cycle fuelreprocessing plant using pyrometallurgical procedures is being designed as part of the Experimental Breeder Reactor No. II project. The reduction of uranium oxide was investigated, using pure Mg and solntions of Mg in Zn and Cd. Cadinium solntions of U were shown to be stable in Types 405 and 410 stainless steel containers at temperatures up to 550 deg C. The liquid metal corrosion loop in which a U-Mg--Cd alloy is being circulated at 550 deg C has been in trouble-free operation for 3000 hrs. Recovery of Pu from Mg solution by distillation of Mg was demonstrated on 1-g Pu scale. The solubility of Th in liquid Cd was measured over the temperature range from 1.9 x 10/sup -3/ per cent at 348 deg C to 1.8 x 10/sup -2/ per cent at 658 deg C. The solubility of Mn in liquid Cd was found to range from 0.27% at 414 deg C to 1.43% at 661 deg C. The solubility of Ni in liquid Cd was measured. The partition of U between liquid Al and liquid Cd was studied as a function of U concentration. The reaction of Al with a liquid Cd solution containing …

A neutron-sensitive semiconductor counter was constructed by depositing a thin layer of Li/sup 6/F between two silicon surface-barrier counters. Neutrons are detected by observing the alpha + T pair resulting from the Li/sup 6/(n, alpha )T reaction; pulses from the two counters are added, and the sum pulse is amplified and recorded on a multichannel analyzer. Since the sandwich geometry permits simultaneous detection of both reaction products, the magnitude of the resulting sum pulse is proportional to the energy of the incoming neutron. Pulse-height spectra from slow neutrons and monoenergetic fast neutrons. in the energy region 0.6 to 3.5 Mev, were recorded from two counters of this type; in both counters the sensitive area was about 0.7 cm/sup 2/, with a Li/sup 6/F layer of order 150 mu g/cm thick. In all cases. a well defined neutron peak was observed in the pulse-height spectrum. In a typical case the full width at half maximum of the fast-neutron peak was about 300 kev. Counters of this type are relatively insensitive to background effects, notably gamma rays, and thus may prove to be useful in the detection and spectroscopy of fast neutrons. (auth)

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Report documenting the progress of the Army Gas-Cooled Reactor Systems Program to develop a mobile nuclear power plant for military field operation.

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Techniques for improving stability of scintillation counter chopper systems and their development for use in industrial control applications are being investigated. Tests are being performed to determine the causes of fluctuations. An integration and frequency converter is being developed in which the anode current of the photomultiplier tube is alternately switched between two integrating condensers by action of a commutator switch. The voltages developed across the two condensers are proportional to the respective intensities of the two radiation beams seen by the scintillation counter. Slective sampling by the use of Loss filters is scheduled for future investigations and a literature search on counter stabilization is also planned. (J.R.D.)

Progress is reported in corrosion studies of stainless steels, Nb, Zr, Al- Fe-Mo, Mo, Ni alloys, and Al- Ni by various materials including Na, Na-K, Li, Rb, and fused salts, Corrosion studies in pump loops of various materials by fused salts and liquid metals are reported, Fuel elements and shielding materials for ART and APPR are beirg developed. General studies in welding and brazing, nondestructive testing, fabrication, and inspection are described. Developments in high-temperature metals and ceramics, metallographic techniques, ceramic materials, and Zr alloys are reported, (T.R.H.)

ABS>Fuel Element Research and Development. Dynamic and static corrosion tests on 8001 Al were completed. Annealmmmg of 1100 cladding on 5083 and M400 cladding on X2219 were tested at 500 deg C, and investigation continued on producing X8101 Al alloy cladding in tube plates by extrusion. Boiler fuel element capsule irradiation tests and subassembly tests are described Heat transfer loop studies and fuel fabrication for the critical facility are reported. Boiler fuel element mechanical design and testing progress is desc ribed. and the superheater fuel element temperature evaluating routine is discussed. Low- enrichment superheater fuel element development included design studies and stainless steel powder and UO/sub 2/ powder fabrication studies Reactor Mechanical Studies. Research is reported on vessel and structure design, fabrication, and testing, recirculation system design, steam separator tests, and control rod studies. Nuclear Analysis. Reactor physics studies are reported on nuclear constants, baffle plate analysis, comparison of core representations, delayed neutron fraction. and shielding analysis of the reactor building. Reactor and system dynamics and critical experiments were also studied. Chemistry. Progress is reported on recombiner. radioactive gas removal and storage, ion exchanger and radiochemical processing. (For preceding period see ACNP-5915.) (T.R.H.)

Operating instructions are presented for DMM, a Remington Rand 1103A program using one-space-dimensional multigroup diffusion theory to calculate the reactivity or critical conditions and flux distribution of a multiregion reactor. Complete descriptions of the routines and problem input and output specifications are also included. (D.L.C.)

Progress in development of a nuclear density gage for use in thickness and density measurements is reported. A Ross filter system for energy discrimination in the alpha ray region was constructed. Soller slits for collimating the radiation entering and leaving the filters so that a constant absorber thickness is seen by the radiation beam is under construction. Comments by visiting Russian scientists on the density gage and a discussion of their work in this area are included. (J.R.D.)

A summary of each computer program initiated during the report period together with code symbols indicating the extent to which information concerning the program is readily available are given. Programs previously reported are included if changes were made or additional information concerning them was placed in the program library. Abstracts of 704 newsletters and GEORGE bulletins are presented. (For preceding period see ANL-6089.) (W.D.M.)

The rate of reaction of highly irradiated U with air, CO/sub 2/, and steam was studied in sn investigation of the fission product release potential in a loss-of-coolant type accident postulated for Pu-producing reactors. Highly irradiated U was found to be more reactive, probably because of the defects in the oxide coating formed by the inclusion of fission products. Complete oxidation or melting was found to release rare gases, I, and Te semi- quantitatively in most atmospheres. Other fission products (Ru, Cs, and Sr) were released to a lesser extent and apparently in proportion to the amount of self- heating induced. In order of their relative tendency to release fission products, the atmospheric conditions investigated were rated in the order: air > CO/sub 2/ > steam. (auth)

The papers presented at the meeting were recorded and transcripts are given along with the discussion which followed each paper. Separate abstracts were prepared for 12 of the 13 papers presented. (W.D.M.)

Fluoride Volatilization Separations Process. Development of a fused fluoride process for dissolution of uranium-- zirconium fuel alloys continued. In corrosion tests to find a suitable container material, Ni was found to be susceptible to a sulfur-type attack. Hastelloy B showed promise, and graphite offers excellent chemical resistance but poor mechanical strength. The dissolution rate of Zr in NaF-- ZrF as affected by impingement of the HF sparge was studied. Production of UF/sub 6/ by fluidized bed fluorination of UF/sub 4/ from ore concentrates was studied. The preparation, melting point, vapor pressure, and vapor density of UF/sub 5/ are given. Preliminary dissolution and recovery runs in semi-works equipment are discussed. Fluidization. Fluidized- bed techniques have been applied to conversion of UO/sub 2/(NO/sub 3/)/sub 2/ to UF/sub 4/ and to calcination of radioactive liquid wastes. Activities of the Green Salt Pilot Plant and shakedown runs of the shielded waste calciner are described. Reactor Chemistry. Studies continued on the kinetics and mechanism of oxidation of U, Th, and Zr. Data are given for oxidation of U in oxygen from 125 to 295 tained C and 20 to 800 mm pressure, and for Zr from 400 to 900 tained C and 200 nan O/sub …