Showing papers by "Pacific Northwest National Laboratory published in 1971"
TL;DR: In this article, the thermal conductivities of (U, Pu)O2 solid solutions containing up to 30 wt% PuO2 were determined from measurements of thermal diffusivity.
127 citations
TL;DR: In this article, the total cross section of neutrons between 2.5 and 15 MeV was obtained by transmission in good geometry (inscattering 0.3%), using time-of-flight analysis of the continuous spectrum of the neutrons from a pulsed L 2 (d,n) source.
Abstract: We have completed measurements of the total cross section, for neutrons between 2.5 and 15 MeV, of 78 natural elements and 14 artificial or isotopically enriched samples spanning the range from hydrogen to plutonium. The measurements were made by transmission in good geometry (inscattering 0.3%), using time-of-flight analysis of the continuous spectrum of neutrons from a pulsed $\mathrm{Li}(d,n)$ source. Data were taken with moderate energy resolution (2 to 4%) and moderate precision (1 to 3% at each point) at a density of three or four points per resolution interval, in order to avoid leaving gaps. We believe systematic errors do not exceed 2%, except in particular cases. Our method leads naturally to small samples, so that we were able to include all of the stable elements except the noble gases. The resulting homogeneous set of data supplies a reference surface for the intercomparison of results from other laboratories. We have made detailed comparisons with virtually all previous measurements in this energy range, and we summarize the systematic properties of the major ones. The completeness of the set helps to reveal a number of systematic properties of the interaction of fast neutrons with nuclei over the entire range of masses.
94 citations
01 Dec 1971
TL;DR: Particle effective eddy diffusion coefficients, ϵ/ν, [(inertial + diffusion)/viscous forces], were calculated from experimental deposition fluxes to a smooth horizontal surface as discussed by the authors.
Abstract: Particle effective eddy diffusion coefficients, ϵ/ν, [(inertial + diffusion)/viscous forces], were calculated from experimental deposition fluxes to a smooth horizontal surface. The ϵ/ν are a function of both particle inertia (τ+), the distance from the surface (y+), and the air friction velocity ( u ∗ ) which is contained in both dimensionless terms. These ϵ/ν are greater than the ϵ/ν for particle deposition along a vertical surface. Both correlations show that particle effective eddy diffusion coefficients are much greater than the eddy diffusion of air momentum for distances from the surface of y+ 350. These ϵ/ν are similar to those for air momentum transfer. The effective eddy diffusivities are combined with Brownian diffusion and gravity settling to predict particle deposition velocities for particle size from 10−3 to 102 μm diameter for particle densities of 1 and 10 gm/cm3. Each of these mechanisms of particle transport controls the predicted deposition in some range of particle size. The deposition velocities show minima of 1.8 × 10−4 to 7.7 × 10−3 cm/sec for particle sizes from 0.066 to 0.54 μm. The minima as well as all deposition velocities are equal to or much greater than predicted from gravitational settling.
68 citations
TL;DR: In this article, the authors measured cross sections, differential in ejection energy and angle, for electron emission from nitrogen following proton impact, for protons with energies from 0.3 to 1.7 MeV.
Abstract: Cross sections, differential in ejection energy and angle, for electron emission from nitrogen following proton impact were measured for protons with energies from 0.3 to 1.7 MeV. Electrons were detected at emission angles from 20\ifmmode^\circ\else\textdegree\fi{} to 130\ifmmode^\circ\else\textdegree\fi{} with energies from a few eV to approximately 4000 eV. Cross sections differential in energy were obtained from the doubly differential cross sections by integration with respect to the emission angle. These results were compared with cross sections calculated from binary-encounter theory. Agreement between the calculated and measured cross sections was within experimental uncertainties (25%) throughout most of the energy range of the ejected electrons. $K$-shell ionization cross sections for nitrogen were also estimated from the intensity of the $K$ Auger electrons emitted following proton impact.
60 citations
TL;DR: In this article, a face centered cubic superlattice of voids was discovered in nickel which had been irradiated to 400 dpa and the resultant swelling was found to increase as the 1.45 power of the displaced atom density until approximately 50 dpa.
60 citations
TL;DR: In this article, the widths of the hydrogen vibration peaks are found to depend upon the zirconium-to-hydrogen ratio as well as upon the momentum transferred in the scattering process.
Abstract: Neutron double-differential cross sections of four polycrystalline samples of $\mathrm{Zr}{\mathrm{H}}_{x}$ with hydrogen-to-zirconium ratios ($x$) of 0.54, 1.03, 1.56, and 2.00 have been measured with high-energy resolution by downscattering of neutrons from initial energies of 171.5 and 244.8meV. Clear evidence of structure in the one-phonon optical peak of Zr${\mathrm{H}}_{2}$ is observed for the first time. This structure consists of two maxima located at energy transfers of 137 and 143 meV and a shoulder located at 154meV. Similar structure is indicated for the other hydride samples but it becomes less well defined as the hydrogen-to-zirconium ratio decreases. The observed structure is compared with predictions of a central-force model calculation by Slaggie, which includes the effects of interactions between hydrogen atoms. The widths of the hydrogen vibration peaks are found to depend upon the zirconium-to-hydrogen ratio as well as upon the momentum transferred in the scattering process.
50 citations
TL;DR: The concepts of linear elastic fracture mechanics were used to evaluate the fatigue behavior, and it was found that the crack-growth rate was higher under simulated body conditions than for a corresponding test conducted under ambient air conditions.
Abstract: The fatigue-crack propagation behavior of Type 316 stainless steel was studied under simulated body conditions. The fatigue specimens were immersed in circulating Ringers Solution at a temperature of 98°F. Cyclic loading was accomplished at a frequency and load waveform that corresponded to normal level walking. The concepts of linear elastic fracture mechanics were used to evaluate the fatigue behavior, and it was found that the crack-growth rate was higher under simulated body conditions than for a corresponding test conducted under ambient air conditions.
45 citations
39 citations
TL;DR: In this paper, a technique was developed for determining the oxygen-to-metal ratio of nonstoichiometric uranium, plutonium, and mixed uranium-plutonium oxides, which is based on determining the weight change which occurs when the starting oxide is heated at 800 °C for six hours in an atmosphere in which the oxygen potential is maintained at approximately −101 kcal/mole O 2.
39 citations
TL;DR: In this article, the authors examined the relationship between peak-to-mean ratios and the time-ratio in the atmosphere and found that the relationship was not as simple as the simple power law relationship suggested by several workers.
37 citations
TL;DR: In this article, the size and density of voids in high purity nickel that had been irradiated to 3 × 1021n/cm2 (>0.1 MeV) at 450°C and subsequently annealed for 2 hr at 650, 800, 900, 975, 1050 and 1150°C.
TL;DR: Calculations showed that, in areas in the North Pacific outside the influence of upwelling, percentage 65Zn loss from sinking molts was likely to be the same throughout the year, since the molts would be exposed to about the same mean temperature in the water column in all seasons.
Abstract: The elimination of 3 radionuclides from Euphausia pacifica was measured over a 5 month period. The biological half-lives for 65Zn, 137Cs, and 144Ce, calculated after the euphausiids had ingested radioactive Artemia nauplii, were found to be 140 days, 6 days, and 7.5 h, respectively. The percentages of body burdens lost in molts were greatest for the fission products, 144Ce (21%) and 137Cs (7%), and least for 65Zn (1%). Elimination of the isotopes in the feces could not be followed because of the difficulty in collecting fecal material for analysis; however, 1 sample collected 2 months after the beginning of the elimination experiment had no measurable radioactivity. Loss of 65Zn from molts and time to disintegration of the molts were found to be temperature dependent over a 5° to 15°C range, and the sinking rate of molts was both temperature and salinity dependent. Calculations showed that, in areas in the North Pacific outside the influence of upwelling, percentage 65Zn loss from sinking molts (before disintegration of the molts) was likely to be the same throughout the year, since the molts would be exposed to about the same mean temperature in the water column in all seasons. Even though temperature structure in the upper layers changes with season, mean temperatures change very little when calculated over the sinking distance of intact molts. Intact molts would sink to slightly over 400 m in the absence of turbulence, and would lose 87% of their 65Zn by the time they reached this depth. Sinking molts thus might contribute substantially to the vertical transport of 65Zn in the sea. If loss of 65Zn in fecal pellets is assumed to be small under our experimental conditions, and molting loss is only 1% of 65Zn body burden, the major mechanism of 65Zn loss from euphausiids feeding on non-radioactive food must be isotopic exchange with the water. Approximately 96% of the initial body burden was eliminated over a period of 5 months.
TL;DR: In this paper, it is demonstrated that the kinetics of the anodic dissolution process determine the cathodic polarization required for adequate protection, which may provide a basis for more fundamental cathodic protection criteria.
TL;DR: In this article, an attempt is made to relate the unusual irradiation behavior of Poco graphite to its microstructure, showing that the graphites behave isotropically under irradiation and show improved dimensional stability over conventional nuclear graphites.
TL;DR: In this article, eight large-scale spray experiments have been made in the 26 500 ft3 Containment Systems Experiment (CSE) vessel and the spray fluxes ranged from 0.025 to...
Abstract: Eight large-scale spray experiments have been made in the 26 500 ft3 Containment Systems Experiment (CSE) vessel. In each experiment a major parameter was changed. Spray fluxes ranged from 0.025 to...
TL;DR: In this paper, the authors discussed the philosophy behind the use of high energy, heavy ions to simulate high fluence, fast neutron damage, and the experimental techniques used to bombard samples with heavy ions are also described with particular emphasis on a tandem accelerator to attain ion energies in the 1 to 14 MeV range.
TL;DR: In this article, the authors studied the relationship between particle deposition and the observed particle flux passing in turbulent flow adjacent to the deposition surface in a vertical tube and showed that the particle flux is a function of whether or not the surface is a perfect sink for particles.
01 Jun 1971
TL;DR: In this paper, the relative toxicity of oil, chemical dispersants, and oil-dispersant mixtures to naturally occurring populations of phytoplankton, and representative marine phytoplankters grown in pure culture is evaluated.
Abstract: Recommended bioassay procedures are presented that can be routinely applied to evaluate the relative toxicity of oil, chemical dispersants, and oil-dispersant mixtures to 1) naturally occurring populations of phytoplankton, and 2) representative marine phytoplankters grown in pure culture. The methods presented, in general, represent 1) application of techniques routinely employed in the measurement of marine primary productivity, and 2) application of the Inhibitory Toxicity Test, a tentative method devised by the American Society for Testing and Materials to evaluate acute toxicity of industrial wastes to diatoms.
TL;DR: In this paper, a comparison of displacement rates produced by ion bombardment and neutron irradiation is made, and it is shown that irradiation has a higher displacement rate than ion bombardment, while ion bombardment has lower displacement rates.
Abstract: (1971). Comparison of displacement rates produced by ion bombardment and neutron irradiation. Radiation Effects: Vol. 9, No. 3-4, pp. 283-284.
TL;DR: In this paper, the authors investigated the minimum creep-rate behavior of polycrystalline vanadium over the temperature range of 477-1600°C (0.35-0.87 T m ).
TL;DR: In this paper, the inert gas 85Kr was released at surface level and were permitted to drift through a three-dimensional grid of Geiger counter sensors extending to a height of 21 m and to a distance of 800 M. Concentrations were recorded as a series of 4.8sec duration mean concentrations for each of the 64 sensors.
Abstract: Puffs of the inert gas 85Kr were released at the surface level and were permitted to drift through a three-dimensional grid of Geiger counter sensors extending to a height of 21 m and to a distance of 800 M. Concentrations were recorded as a series of 4.8-sec duration mean concentrations for each of the 64 sensors. Data specifying the effective speed, the effective height, the magnitude of short-period concentrations, the magnitude of crosswind and downwind concentration integrations, and the dimensions of puffs are reported. It was found that: 1) the speed with which a puff reached a 1.5 m elevation field sensor increased with distance from the source (or with travel time); 2) at the 1.5 m elevation, peak values of short-period concentration, exposure, and crosswind integrated concentration increased with increasing atmospheric stability; 3) regardless of the atmospheric stability, puff dimensions along a downwind axis exceeded those along a crosswind axis, and the crosswind dimension exceeded t...
01 Sep 1971-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the same carbon composition as the multiphase source materials were produced by high rate sputter-deposition techniques and were 0.005 to 0.027 in.
Abstract: Supersaturated iron-carbon solid solutions containing 0.06, 0.18, 0.66, 2, 3, and 5 wt pct C were produced by sputter-deposition at 6° to 21°C. Homogeneous deposits of the same carbon composition as the multiphase source materials were produced by high rate (up to 0.0004 in. per hr) sputtering techniques and were 0.005 to 0.027 in. thick. The microhardnesses of the deposits were higher than the hardnesses of martensite with the same carbon content. The hardness increased rapidly from 680 Dph for 0.06 wt pct C content to an unusually high maximum of 1240 Dph at 2 wt pct C and then decreased slowly to 920 Dph at 5 wt pct C. The 0.06, 0.18, and 0.66 wt pct C deposits were bcc, and the 2 and 3 wt pct C deposits were bct. The tetragonality of the 5 wt pct C deposit was detected only after tempering at 150°C. Lattice parameterc/a ratios for the tetragonal deposits were lower than expected from extrapolated martensite data, and they corresponded to the equationc/a=1.06+0.019 (wt pct C). Nevertheless, thec/a ratio of 1.10 for 5 wt pct C deposit was higher than previously observed for martensite. No evidence of a martensitic transformation was found in the microstructures, which typically consisted of 0.5 to 1.0 μ diam columnar grains. Hardness data from tempered eposit samples and the lack of tetragonality of the low carbon deposits indicated that autotempering occurred during sputter-deposition.
TL;DR: Carbon blacks have been found in binder regions of typical pitch-bonded graphites as discussed by the authors, and they appear to be part of the quinoline-insoluble fraction of the coaltar pitch binder used in graphite manufacture.
TL;DR: In this paper, the geometric theory based on minimum shear and shuffles is shown to predict twinning elements K1K2η1η2; g as {110} 10〈110〉〈 110〉; 0.068.
TL;DR: In the latest series of experiments in a continuing program for determining the critical parameters of plutonium mixtures having concentrations typical of wet powders, precipitates, slurries, and polymers, the minimum critical slab thickness for a water-reflected homogeneous PuO2-water system of this composition was determined to be 2.31 ± 0.06 cm as discussed by the authors.
Abstract: The results and analyses presented are from the latest series of experiments in a continuing program for determining the critical parameters of plutonium mixtures having concentrations typical of wet powders, precipitates, slurries, and polymers. Previous measurements in this program were made on 15 H/Pu fuel having 240Pu isotopic concentrations of 2.2 and 8.08 wt% and on 5 H/Pu fuel having a 240Pu isotopic concentration of 11.46 wt%. This latest series of experiments was conducted with fuel in which the 240Pu isotopic content has been increased to 18.35 wt% and the H/Pu atomic ratio decreased to essentially zero. The minimum critical slab thickness for a water-reflected homogeneous PuO2-water system of this composition was determined to be 2.31 ± 0.06 cm as compared to only 1.15 ± 0.03 cm for Pu-water. Thus, having the plutonium in an oxide form at this degree of moderation results in an increase of about a factor of 2 in the critical thickness. For spherical geometry, the difference in critical mass bet...
TL;DR: A comparison of a Mossbauer through-transmission geometry to backscatter geometry shows the latter to have a larger percent effect and therefore an advantage in counting time as mentioned in this paper, which shows that the latter is more accurate than the former.
TL;DR: The ratio βeff/l has been deduced from reactor noise measurements in several uniform light-water lattices in the Plutonium Recycle Critical Facility as discussed by the authors, including one in which the fissil...
Abstract: The ratio βeff/l has been deduced from reactor noise measurements in several uniform light-water lattices in the Plutonium Recycle Critical Facility. These lattices included one in which the fissil...
01 Nov 1971-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the hardness of iron-carbon sputter deposits was compared to severely cold-worked martensite, both as-deposited and in tempering response, and the results showed that these three deposits were much harder than water quenched steels of the same composition.
Abstract: Iron-carbon sputter deposits with 006, 018, 066, 2, 3, and 5 wt pct C were tempered at temperatures from 100° to 550°C The 006, 018, and 066 wt pct C sputter deposits were similar to severely cold-worked martensite, both as-deposited and in tempering response Specifically, these three deposits were much harder than water quenched steels of the same composition, and the deposit hardnesses decreased less than martensite hardnesses on tempering below 400°C The hardnesses of the 2 and 3 wt pct C deposits increased 40 to 50 Dph units upon tempering at low temperatures (150° to 250°C) and decreased for higher tempering temperatures The hardness of the 5 wt pct C deposit remained constant (920 Dph) after tempering at 150°C, but increased to 1170 Dph upon tempering at 250°C when monoclinic Hagg carbide (Fe5C2) formed Cementite (Fe3C) was the only other carbide detected in the tempered deposits, and it formed only at 475°C and above The columnar grains of the sputter deposits transformed to equiaxed grains upon tempering above 250°C This change in grain structure was due to recovery and not recrystallization Some grain growth occurred in the 006, 018, 066, and 2 wt pct C deposits above 300°C, but the grain size of the 3 and 5 wt pct C deposits remained submicron The hardnesses of the deposits after tempering at 550°C increased with carbon content, the 5 wt pct C deposit having the highest hardness (960 Dph) and the 006 wt pct C deposit the lowest (360 Dph)