[en] One of the critical requirements for a protective oxide scale on an alloy substrate to provide high temperature environmental resistance is that the scale should be adherent to the substrate. A directionally solidified (DS) alloy IC6 has been recently developed as a high-temperature structural material used for advanced jet-engine blades and vanes operating in the temperature range of 1,050-1,150 C. Its high temperature oxidation resistance is substantially improved by adding proper amounts of yttrium, which is attributed to several beneficial roles played by yttrium. One of the beneficial effects is that yttrium can inhibit the transportation of cations and hence decrease the increasing rate of the depth of the diffusion layer formed during high temperature oxidation process. The purpose of this paper is to investigate the effect of yttrium on the diffusion layer

[en] Degradation of components in nuclear power reactors due to flow-induced vibration remains an important issue affecting service life. This paper presents the recent upgrade of the VIBIC code to use measured quasi-static force coefficients for predicting fluidelastic instability in steam-generator tubes. (author)

[en] A trap model is introduced to describe the behaviours of both thermally sensitive and radiation sensitive TL traps. The former are relatively shallow traps. The latter are deep traps, in which population increases with exposure to alpha dose. Thermal decay of both types of traps at ambient temperature is dependent on the trap lifetimes. A trap's population can be measured as TL sensitivity to a laboratory test dose. The trap model has been supported by observations of age dependent TL signals from granitic quartz samples with different crystallisation ages. The trap lifetimes are from 1.98 x 10⁹ to 5.36 x 10¹⁵ years estimated using the isothermal decay experiment with the assumption of first order kinetics. Dating techniques are proposed based on the trap model. For old granites (>400 Ma), ages can be obtained by measuring the total exposed alpha dose using the additive alpha dose method, whereas for young granites (<400 Ma), ages can also be obtained by interpolating the TL sensitivity to a curve of TL sensitivities for known ages. (author)

[en] The double-differential cross sections of outgoing neutrons and alpha particles of the ¹²C(n,xn) and ¹²C(n,χα) reactions are measured. A new nuclear reaction model for light nuclei is proposed to analyze the measured data. Because of a strong recoil effect in light nucleus reactions, the energy balance is strictly taken into account. Based on this new method, the LUNF code is developed to calculate all kinds of reaction cross sections and energy-angular distributions for the n + ¹²C reaction in the 4.8- to 20-MeV energy region. The reaction channel of (n,nprime3α) may proceed via a number of different reaction channels, as sequential particle emissions and two-body separation. The comparisons of the calculated results with the measured experimental data indicate that the model calculations are successful for outgoing neutrons. Also, kerma factors derived from the calculated results are compared with the measurements

[en] Excitation functions for proton-induced reactions on ⁵²Cr and ⁵¹V for which there had been no experimental data were reasonably predicted by the newest theoretical calculation program at incident proton energies from threshold to 30 MeV. The set of calculation parameters used here was obtained from threshold to 65 MeV, based on the available experimental data

[en] An immediate EM science need is a reliable kinetic model that predicts long-term waste glass performance

[en] Degradation of components in nuclear power reactors due to flow-induced vibration and consequent fretting wear remains an important issue for reactor safety and life. This paper reviews AECL's existing technology for flow-induced vibration assessment of steam generator tubes and reactor fuel assemblies, and presents studies to assess the potential for vibration-related damage of steam-generator tubes at the Qinshan Nuclear Generating Station and fuel rods in a Generation-IV Super-Critical Water-cooled Reactor. (author)

[en] Calcite crystals were nucleated from MgCl2/CaCl2 solutions onto functionalized self-assembled monolayers adsorbed onto E-beam evaporated Au films. Synchrotron X-ray scattering studies of the crystals reveal new information about preferred orientation and Mg incorporation. The Au [111] axis is distributed within 2.6 degrees of the film surface normal, but the oriented crystals may be tilted up to 6 degrees away from this axis. For low Mg²⁺ content, SO₃--functionalized films nucleated primarily near the (106) calcite face, odd-chain-length carboxylic acid terminated alkanethiol films nucleated near the (012) face, and even-chain-length carboxylic acid terminated alkanethiol films nucleated near the (113) face. [Mg²⁺]/[Ca²⁺] concentration ratios (n) of 2 and greater defeated this preferred orientation and created a powder texture. Diffraction patterns within the layer plane from the coarse calcite powders indicated a shift to higher 2 accompanied by peak broadening with increasing n. For 0.5 < n < 3.5, a double set of calcite peaks is observed, showing that two distinct Mg calcite phases form: one of comparatively lower Mg content, derived from the templated crystals, and a Mg-rich phase derived from amorphous precursor particles. According to the refinement of lattice parameters, Mg incorporation of up to 18 mol % occurs for n = 4, independent of film functionality. We discuss the differences between the differently functionalized monolayers and also introduce the hypothesis that two separate routes to Mg calcite formation occur in this system

[en] The standard heat treatment of cast nickel-base superalloy K403 is the solid solution treatment of 1210 C/4 h, air-cooling. It is very difficult to meet the requirements of the intermediate temperature stress-rupture life regulated by aviation standard HB5155. In order to resolve the above problem, some factors influencing intermediate stress-rupture life have been explored. The results showed that the intermediate temperature stress-rupture life have been explored. The results showed that the intermediate temperature stress-rupture properties impaired by treatment of 1210 C/4 h were due to precipitation of too small γ' phase (<0.2 μ m) in grains and absence of the secondary carbides at grain boundaries. The dendritic pattern appears at the fracture surface and there is no slip trace at the gauge length part of specimens treated by 1210 C/4 h, but the crystallographic plane at fracture surface and the extensive slip can be observed for the specimens treated by 1180 C/4 h. TEM results have shown that during intermediate temperature deformation the dislocation of 1/2 left angle 110 right angle moves to the interface of γ/γ' and cuts γ' phase to form the high energy antiphase boundaries. The finer γ can be cut and passed easily by dislocation and has a poor resistance to intermediate temperature creep. The finer dendrites and the microstructure containing intergranular M6C carbide with envelope of γ' and residual coarse γ' within grains were beneficial. Therefore high cooling rate during solidification and partial solid solution treatment of 1180 C/4 h are suitable for a turbine blade alloy K403. (orig.)

[en] The small angle neutron scattering techniques is very useful for the study of microstructual inhomogeneities with size of 1nm to 100nm range in various materials such as metals, ceramics, polymers, boi-molecules, etc. The small angle neutron spectrometer(SANS) has been installed at CN beam port of HANARO reactor. After commissioning it will be opened to internal and external users in the middle of 2001. This report reviews basic theory of SANS and recent trends of materials studied by using SANS technique for the material researchers. We, also, wish to review feasibility of small angle studies for materials science fields at HANARO SANS and to help possible beam time users for their experimental consideration