Detailed consideration is given to some properties of the first excited electronic state. Following the analysis proposed by Mulliken, SCF LCAO-MO coefficients are used to obtain qualitative information about the electron distribution. Comparison is made with earlier work with respect to the description of the excited state in terms of the interacting configurations. In addition to the excited-state dipole moment, the effective electric moment between the ground and excited states is also calculated. From this, the oscillator strength for the first allowed transition is computed as a function of the internuclear distance. (auth)

The stability of unclad zirconium hydride was investigated as a reactor moderator in carbon dioxide coolant. Two ranges of hydride were tested, an alpha- plus deltaphase hydride (ZrH/sub 0.9 plus or minus 0.2/) and a delta-phase hydride (ZrH/sub 1.5/). The delta-phase hydride exhibited excellent dimensional stability, but suffered as great as 20% hydrogen loss at 1200 deg F, together with severe corrosion. The alphaplus delta-phase hydride swelled and warped in a temperature gradient but did not lose much hydrogen and did not corrode severely even at 1200 deg F. The results indicate that zirconium hydride could not be used as unclad moderator in a carbon dioxide atmosphere in the temperature range desired for the Maritime Gas Cooled Reactor. (auth)

In research in support of the GCRE, procedures for the fabrication of stainless steel-clad flat-plate fuel elements having a core of 28 w/o UN dispersed in an iron-18 w/o chromium--14 w/o nickel--2.5 w/o molybdenum matrix were developed. The preparation of UN and its compatibility with the components of the matrix alloy were studied. The UN for the program was prepared by nitriding uranium metal at 850 C and then dissociating the U/sub 2/N/sub 3/ produced to UN in a vacuum at 1300 C. In compatibility studies, UN reacted with nickel alone at 1800 F, but no reaction with nickel was observed when the other matrix components were also present. The effects of fabricational variables were evaluated by metallographic examination, longitudinal and transverse tensile tests, bend tests, and corrosion tests. Studies indicated that minus 200 plus 325-mesh UN dispersed in a minus 325-mesh elemental-powder matrix rolled green vith a 30 per cent initial reduction at 2100 F and then annealed 3 hr at 2300 F produced the best fuel core. (auth)

The properties of zirconium alloyed with aluminum tin, and molybdenum were investigated. Using reactorgrade zirconium sponge, 11 zirconium-base alloys were double arc-melted and cast into 6-in.-diam. ingots weighing 35 lb each. By such standard hot working procedures as extruding and rolling, the ingots were converted to 1/8-in.-thick strips. The extruded and rolled products were used for a variety of evaluation studies which included corrosion thermal conductivity, tensile, and creep tests. The alloys demonstrated short-time elevated temperature strength properties equal to or greater than type-304 stainless steel. Their corrosion resistance in sodium, at 1000 deg F, compares favorable with that of unalloyed zirconium. The creep resistance and the thermal conductivity were found to be less than those for type-304 stainless steel, but adequate for nuclear reactor application. (auth)

Sawing studies were made using a dry function blade for cutting Zircaloy taking. An off-gas filtration system including a rotoclone and a filter assembly was installed to permit studying of the particulate material generated during the friction cutting operations. Studies of mechanical techniques for safety processing the Na or NaK alloy reservoirs present in some non-production fuels have continued. Stainless steel-clad swaged U0/sub 2/ rods and stainless steel- clad U- 10 wt.% Mo alloy rods were sheared under water to investigate the mechanical and particulate handling problems associated with these two major components of the power reactor fuels reprocessing program. The behavior of explosive U- Zr residues in the Zirflex Process was studied. In dissolution of stainless steel cladding from U0/sub 2/ it was found that a more rapid initial U0/ sub 2/ dissolution by H/sub 2/SO/sub 4/ occurred if the U0/sub 2/ was exposed to the atmosphere. Farther studies on the dissolution of ingot U and sintered U0/ sub 2/ in HNO/sub 3/ and HNO/sub 3/- ferric nitrate are reported. The dissolation of U-Mo alloys is being studied. The corrosion of 304-L stainless steel and Hastelloy-F in nitric acid-ferric nitrate systems was studied. Exploratory experiments were done attempting to …

The preliminary design of a 3095-Mw(thermal), helium-cooled, graphite- moderated reactor employing sign conditions, 1500 deg F reactor outlet gas would be circulated to eight steam generators to produce 1050 deg F, 1450-psi steam which would be converted to electrical power in eight 157-Mw(electrical) turbine- generators. The over-all efficiency of this nuclear power station is 36.5%. The significant activities released from the unclad graphite-UO/sub 2/ fuel appear to be less than 0.2% of those produced and would be equivalent to 0.002 curie/ cm/ sup 3/ in the primary helium circuit. The maintenance problems associated with this contamination level are discussed. A cost analysis indicates that the capital cost of this nuclear station per electrical kilowatt would be around 0, and that the production cost of electrical power would be 7.8 mills/kwhr. (auth)

None

Given the moments of a function it is often desirable to obtain a numerical approximation of the function. A method for estimating the solutions of the Stieltjes and Hamburger moment problems is developed. Calculations indicate that the method is both feasible and accurate. (auth)

Progress is reponted on lifetime tests of rotors and determination of power loss of the scoop system. (T.R.H.)

ABS>Estimates have been made of what the probable radionuclides produced in weapons detoriations, including fission products and neutron-induced radionuclides in air, soils, and sea water will be. The nuclear and decay properties and some metabolic or biological properties of these nuclides are tabulated where available. Estimates are made of the amounts of the radionuclides produced in weapons detonations. Some radionuclides are discussed with respect to their particular biological interest from the standpoint of the hazard to man. (auth)

Weight change vs. time curves expressing the corrosion behavior of zirconium alloys containing additions of 10 through 60 wt.% uranium tested in 600 and 680 F water and in 750 F steam at 1500 psi are presented. The effects of various heat treatments on the subsequent corrosion properties are also included. (auth)

A Lecture Delivered at Sandia Corp., Albuquerque, N. Mex.. April 8, 1959. The type and nature of plasmas considered are defined, and it is shown that significant results are quite general and can be applied to large classes of plasmas. The physical phenomena are emphasized at the expense of the mathematics. (W.D.M.)

The reaction of U0/sub 2/F/sub 2/ with hydrogen at 700 to 850 deg C was briefly investigated since it could constitute a major step in the recycle of U0/ sub 2/F/sub 2/ in the Fluorox process. The reaction in this temperature range proceeds according to the equation U0/sub 2/F/sub 2/ + H/sub 2/ yields U0/sub 2/ + 2 HF. Rates of the chemical reaction were not obtsined, since, with the thermogravimetric technique used, the rate-controlling process was bed diffusion. However, there is no doubt that the rate of chemical reaction is sufficiently high for the desired application. No significant amount of UF/sub 4/ was formed by the back-reaction, U0/sub 2/ + 4 HF yields UF/sub 4/ + 2 H/sub 2/0. (auth)

None

Tests were conducted to determine methods of removing scale deposits from the HRT heat exchangers. A mockup of the heat exchanger header was cleared of a deposit of iron rust by reverse flushing at a flow rate below 75 gpm. A tube bundle consisting of 109 1/4 in OD X 0.049 in. wall tubes was plugged with rust. Approximately 80% of these tubes were unplugged by using a 70 psi water pressure differential in combination with vibration from a pneumatic rivet gun. No mechanical method was employed in the tests which could clear the remaining tubes. (auth)

Presented at the 1958 Winter Meeting of the American Nuclear Society, December 9, 1958. Experimental and theoretical work on the selflimiting response of reactors to step and ramp insertions of reactivity is discussed along with the general characteristics of self-limiting power bursts. The static characteristics of the cores investigated are presented and the techniques of measurement are discussed. Data from step and ramp tests are presented and compared with the predictions of a theoretical formulation of reactor self- shutdown in terms of energy release. The discussion includes an evaluation of some postulated shutdown mechanisms in the light of experimental results. Some results of detailed calculations of shutdown effects due to specific mechanisms which are believed to contribute significantly to reactor self-shutdown are presented. (auth)

On the basis of screening tests and favorable mechanical propenties, AISI Type 318 stainless steel was selected as a fuel-element cladding material to operate in c coolant comprised essentially of gaseous nitrogen modified by the addition of oxygen and water vapor. Tests at atmospheric pressure confirmed calculations which indicated that small additions of oxygen to nitrogen would inhibit nitriding by the process of preferential oxidation. The tests at atmospheric pressure determined that the rate of oxidation of Type 318 stainless was generally at a minimum when 0.5 volume per cent oxygen was added to the nitrogen gas. Oxidation of this steel was more severe when additions of 0.1 and 5.0 volume per cent oxygen were made to the nitrogen The rate of oxidation was primarily temperature dependent, but was also influenced by time. Oxidation during exposure periods of less than 1000 hr appeared to proceed at a parabolic rate. On longer exposures, however, there wcre indications of more rapid attack. A maximum depth of attack of 2.9 mils was observed on Type 318 stainless which had been exposed at 1650 F for 3658 hr. Stress-corrosion studies indicated that unstressed and stressed specimens were attacked at about the same rate. Stresses …

Comments made hy FMPC personnel on Eurochemic technical documents are given, (T.R.H.)

High heat flux electrical cartridge heaters were tested with direct air cooling under simulated ORR Loop conditions. The cartridges and the heater design were found to be satisfactory. A gas cooler of concentric pipe design utilizing air, water, and air-water mixtures as the coolant was also evaluated and found to be satisfactory. Heat transfer calculations are compared with the experimental data and found to correlate within 10%. (auth)

The first law of thermodynamics for changes of state and quantity of the working substance in the case of unsteady flow is presented. Included are mass balance, forms of energy utilized, and definitions of stagnation enthalpy and stored energy. From the equations for unsteady flow the familiar equations for steady flow are deduced. A special case of the first law of thermodynamics for changes of state and quantity is applied in the theoreticaf derivation on emptying of a vented containment structure having a constant heat source. The appropriate thermodynamic relations necessary for evolvement are stated and a resume on nozzle flow is made. Graphs were plotted for the air temperature, pressure, and mass with respect to time for the constant-pressure and constant- volume processes; for a large vent and a small vent where the same initial pressure is prevalent to the containment structure and atmosphere; and for heating the internal gas to a predetermined pressure and then releasing through a large vent or a small vent. The resultant thermodynamic relations are applied to a hypothetical containment system to illustrate their generality. This hypothetical containment system consists of an extinguishing system, containment structure system, and a venting system. Tables of functions …

In the last twenty years a thermodynamic theory of irreversible processes (TIP) has been vigorously developed which has been able to treat irreversible phenomena in a detailed way. The present macroscopic form of the theory was suggested primarily by the statistical mechanical investigations of Onsager. The presently available experimental data are collected for a variety of quite different irreversible phenomena and it is shown that this evidence does indeed verify the Onsager Reciprocal Relations. Thermoelectricity, electro- kinetics, transference in electrolytic solutions, isothermal diffusion, heat diffusion, heat conduction in anisotropic solids, and thermogalvanomagnetic effects are the phenomena considered in detail. (W.D.M.)

None

A series of neutron multiplication measurements with arrays of 1 by 8 by 10 in. slabs of 93.4% U/sup 235/-enriched uranium metal was made to provide data from which safety criteria for the storage of these fissile units can be established. Each slab contained 22.9 kg of U/sup 235/. A maximum of 125 units was assembled. The arrays studied were cubic lattices of the units and were usually parallelepipedal in shape. Arrays were both unmoderated and Plexiglas- moderated and were surrounded in most cases by a 1-in.-thick Plexiglas reflector. The lattice densities (ratio of fissile unit volume to lattice cell volume) were between 0.023 and 0.06. Unmoderated lattices with a density of 0.06 would require 145 plus or minus 5 units for criticality, while those with a density of 0.023 would require 350 plus or minus 30 units. In lattices in which the fissile units are separated by 1 in. of Plexiglas, approximately 27 units would be required for a critical array with a lattice density of 0.06 and about 75 units for a density of 0.023. Distributing Foamglas (containing 2% boron) throughout a moderated array increased the critical number of fissile units by a factor of 5, while Styrofoam …

The adjoint operator of a matrix operator and adjoint boundary conditions for adjoint matrix operators are defined. It is shown that a matrix operator can be associated in various ways with a scalar differential operator and if two adjoint matrix operators are associated with scalar differential operators then the scalar operators are adjoint. Generalized Green's functions are obtained and their use for solving boundary-value problems is discussed. Properties which characterize a generalized function of Green are obtained and it is shown that the generalized functions of Green of adjoint boundary-value problems are adjoint kernel matrices. Generalized Green's functions for scalar boundaryvalue problems are discussed and special cases taken up. (C.J.G.)