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[en] The following aspects of uranium mine and mill tailings management are reviewed and discussed: (1) the history of the uranium remedial action program, (2) magnitude of the uranium spoils problem, (3) uranium deposits, mining, and milling, (4) status of reclamation, (5) problems in revegetation of uranium spoils and tailings, and (6) health and safety considerations

[en] The following aspects of uranium mine and mill tailings management are reviewed and discussed: (1) the history of the uranium remedial action program, (2) magnitude of the uranium spoils problem, (3) uranium deposits, mining, and milling, (4) status of reclamation, (5) problems in revegetation of uranium spoils and tailings, and (6) health and safety considerations

[en] Three-dimensional (3-D) nodal transport methods have been developed in Cartesian and hexagonal geometry as efficient methods for reactor calculations. We have developed a nodal method that is based on the S_n method, which is considered to be more effective than the double P₁ (DP₁) approximation to describe the angular dependence of the node boundary currents. The efficiency of the method was proved through the Nuclear Energy Agency Committee on Reactor Physics 3-D neutron transport benchmarks in Cartesian geometry. However, for a small fast breeder reactor model with hexagonal geometry, accuracy of the method was not so good, and differences from Monte Carlo results were >0.5% in eigenvalue. Moreover, the solution algorithm was found unstable in some cases and failed to converge. To solve the problem, we have made several improvements on the formulation

[en] Based on the model calculation of VLF hiss power flux spectrum resulting from convective beam amplification of incoherent Cerenkov whistler radiation by the beam of precipitating auroral electrons, the altitude dependence of power flux levels is examined. Their strong altitude dependence suggests that non-linear processes are important in determining the spectrum of VLF hiss at high altitude. It is also shown that estimated power fluxes inside the electron precipitation region at low altitude might not reach as high levels as observed when the electron beam is weak. In this case, wave propagation outside of the precipitation region will account for the high power flux levels as well as significant magnetic components of VLF hiss observed especially at low altitude. In addition, it is shown that the transformation of the electron beam in transit to lower altitudes, determined from Liouville's theorem, may influence appreciably VLF hiss power flux spectrum. Finally, it is pointed out that two types of VLF hiss spectrum observed at the ground level can be accounted for by the difference in strength of the electron beam. (author)

[en] A new method is presented for determining the amplitude at which a single unstable wave in a collisionless plasma saturates due to particle trapping. A non-linear dispersion relation for a small-amplitude test wave, with the same frequency and wavenumber as the main large-amplitude wave, is obtained. The solution of this dispersion equation gives the saturation condition ωsub(t) approximately γsub(l), which is in good agreement with the results of the recent numerical simulations. (U.K.)

[en] Scales equations are derived for the time evolution of a single Whistler wave driven by a weak helical electron beam in the presence of a static magnetic field Bsub(o). These equations can be reduced to those already derived for an electrostatic wave interaction with a cold beam, provided that the perturbation of the perpendicular velocity of an electron to Bsub(o) during the interaction with the Whistler wave is negligible. (author)

[en] The nonlinear development of a plasma-mean system immersed in a static magnetic field B₀ is investigated. The beam electrons are assumed to be streaming parallel to the direction of B₀ and have a spread in the perpendicular component of the velocity. Consideration is restricted to the P instabilities which result in growing whistler waves aligned in a direction parallel to that of B₀. Scaled equations describing the time evolution of these instabilities are derived under the assumptions that the beam density is small and that the resulting whistler wave is nearly sinusoidal. The perturbation of the perpendicular component of the electron velocity during the interaction can be excluded from the equation determining the wave dynamics, and these scaled equations can be reduced to the simpler ones amenable to numerical solution which depends analytically on all the basic parameters of the problem. This solution shows that the amplitude of an unstable whistler wave first increases at the linear growth rate until the electrons are trapped and then, after overshooting, it approaches a steady state. The time evolution of the amplitude does not show an oscillation with a constant period; this results from the phase mixing enhanced by the spread in perpendicular velocities of the beam electrons. (author)

[en] A computer-model was constructed for estimating distributions with time of radiational fluxes at leaf surfaces throughout fruit tree canopies in which leaves did not distribute uniformely in three dimensional space. Several assumptions were set up to construct the model for approximation of using solid geometry. For irregular distribution of leaf area in three dimensional space data were used in the simulation as number of leaves per internal cubic bloc of a cubic grid (n-divided per side). Several main parameters used were peculiar to fruit species which contain parameters (λ, ν) of Beta function to calculate both probability density function of leaf area distribution with respect to inclination angle and leaf extinction coefficient for parallel beam by leaves parameters (A, R_i) to calculate stem extinction coefficient for parallel beam, and parameters (D_i) to calculate leaf extinction coefficient of downward transmission and downward reflection. With these data and parameters solid geometry and Lambert-Beer's law constituted this model

[en] The plasma performance exploration of JT-60U in advanced tokamak regimes based on high βp and reversed shear mode operation has been conducted intensively, by using 500 keV negative-ion based neutral beam injection (N-NBI) and 110 GHz electron cyclotron (EC) systems for plasma heating and current drive, and a repetitive centrifugal pellet injector for efficient core particle fueling. High power injection of 6.2 MW at 381 keV for 1.7 s and a long pulse injection of 10 s at 2.6 MW and 355 keV were achieved. In the EC system capable of generating 4 MW of rf power for 5 s, the maximum injected EC power reached 3.0 MW for 2.7 s so far. Pellet injection at a velocity of 100 m/s from the mid-plane in the HFS has also performed well. With application of N-NBI power of 5.7 MW at 402 keV, a high fusion triple product was increased to n_i (0)τ_ET_i(0), of 3x10²⁰ keV s/m³ under a full non-inductive current drive condition. By using steerable antennas of the EC system and a tracking technique of the MHD island, suppression of the neoclassical tearing mode in real time has been demonstrated successfully. High-magnetic-field-side pellet injection extended the plasma density up to 0.7 n_GW with H_89p kept at ∼2