[en] Brief information concerning thorium as an element, its reserves, mining, and use as nuclear fuel, especially in accelerator driven systems and for the production of uranium 233, is presented. (P.A.)

[en] A new approach to evaluate nuclear photo fissilities at incident photon energies above the pion photoproduction threshold has been recently developed and proved to describe successfully the fissilities of ^natPb and ²³²Th target nuclei at energies ∼ 0.2-4.0 GeV. The method is merely a simple, semiempirical description of the photofission reactions in which fissility, f, is governed by two basic quantities, namely, 1) the first-chance fission probability, f-bar₁, for the average cascade residual, and 2) the slope, s-bar, of the chance-fission probability associated with the average evaporative sequence of fissionable residuals. In the present work we have extended this approach to analyse photofission data that have been accumulated over the past forty years or so, measured at 1 GeV, for nearly forty target nuclei extending from Ti up to Np. Results have shown that the variation of fissility with Z²/A could be described quite satisfactorily by the proposed model. (author)

[en] The cross sections for neutron capture and fission of ²³²Th have been evaluated for ENDF/B-IV

[en] An overview of the authors personal view is presented on open questions in regard to still required research and development work for the thorium fuel cycle before its application in a technical-industrial scale may be tackled. For a better understanding, all stations of the back-end of the thorium fuel cycle are briefly illustrated and their special features discussed. They include storage and transportation measures, all steps of reprocessing, as well as the entire radioactive waste treatment. Knowledge gaps are, as far as they are obvious, identified and proposals put forward for additional worthwile investigations. (orig.)

No abstract available

[en] The fragment anisotropies of the ¹³C+²³²Th system was measured for a range of energies both below and above the barrier

[en] Comprehensive fission measurements, including mass-angle distributions, for the reaction of ³²S with the prolate deformed nucleus ²³²Th at near-barrier energies show two distinct components in both mass and angle; surprisingly, both have characteristics of quasifission. Their relative probabilities vary rapidly with the ratio of the beam energy to the capture barrier, suggesting a relationship with deformation aligned (sub-barrier), or antialigned (above-barrier), configurations at contact

[en] The mean excitation energy E-bar_x of ²³² Th, following photoabsorption in the interval of 40 - 110 MeV, is determined from the nuclear photo fissility measured at Saclay using a novel technique developed at our Laboratory. It is found that E-bar_x of ²'3² Th is considerably lower than obtained from INC-Monte Carlo calculations which, by their turn, describe fairly well the preequilibrium in heavier actinides. It is suggested that this fact could possibly be associated with a higher nuclear transparency of ²³² Th. (author)

[en] The cross section for the neutron-induced fission of ²³²Th target nuclei, σ_f (E_n), was described within statistical theory. The spectra of the mean multiplicity, v-bar (E_n), and the mean energy, E-bar(E_n), of secondary neutrons accompanying ²³²Th fission induced by neutrons of energy extending up to E_n = 20 MeV were analyzed on the basis of the chance structure of the cross section.

[en] The effect of entrance channel mass asymmetry on the fission fragment angular distribution in heavy ion induced fission reactions of fissile targets for certain barrier energies has been explained by the pre equilibrium fission model. In the present study the available experimental data have been analysed on the basis of the pre equilibrium fission model, incorporating two components of fission events