[en] Short communication

[en] At the Paul Scherrer Institute (PSI), hybrid systems with a fast neutron spectrum are extensively investigated. The high-energy particle interaction is treated using the Monte Carlo method. For the transport of neutrons at low energies a deterministic approach is adopted, together with modern nuclear data libraries. (authors). 14 refs., 1 figs

[en] We summarize some of the areas of comparison with experimental data for which the ALICE code did poorly. We suggest some aspects which might be improved in the future. A crude accuracy factor is estimated as a predictive reliability based on the intercomparison exercise. (author). 9 refs., 7 figs

[en] Short communication

[en] A computer version of a Handbook on radionuclide production cross sections in proton-induced nuclear reactions at intermediate energies issued by Springer Verlag Publishing House is presented. (authors). 1 ref

[en] This paper discusses the various physics options available in LAHET, including the Bertini and ISABEL intranuclear cascade models, the multistage. Multistep preequilibrium exciton model, and the level density parameter options. The interdependence, the interaction with evaporation/fission models, and the sensitivity of results to the choice of options is shown. The particular options used in the code comparison benchmark calculations are compared with the other options possible. (author). 23 refs., 9 figs

[en] The role of calculations in the design of spallation facilities is considered in general terms: what needs to be calculated, what needs to be taken into consideration an how the present imprecise knowledge of the uncertainty of such calculations may be circumvented. (authors). 33 refs., 3 figs., 4 tabs

[en] We show how the conservation of linear momentum is fundamental to the description of angular distributions in preequilibrium nuclear reactions. By using state densities with linear momentum to describe the phase space during the preequilibrium cascade, angular distributions can be derived in a transparent way. Fermi-motion and Pauli-blocking effects are included, and correlations between the emission particle's energy and angle are obtained for all orders of scattering. Our model provides a physical basis for the widely used phenomenological systematics of Kalbach, and provides a framework for understanding the systematical properties of continuum angular distributions. (authors). 21 refs., 3 figs

[en] For transmutation systems based on externally driven subcritical assemblies with a fast neutron spectrum, there is an incentive to expose the actinides directly to the source neutrons, since these neutrons have higher energies than the fission neutrons. To clarify the influence of the high-energy models on the transmutation effectiveness of such systems, a sensitivity study based on the Phoenix concept, i.e. a sodium-cooled system with a minor actinide oxide fuelled target, was performed. The calculations show that the difference arising from the use of different basic data sets are quite as significant as the effects of using different source approximations and hence also deserve attention. (authors). 10 refs., 4 figs., 7 tabs

[en] The code GEANT315 has been compared to different codes in two benchmarks. We analyze its performances through our results, especially in the thick target case. In spite of gaps in nucleus-nucleus interaction theories at intermediate energies, benchmarks allow possible improvements of physical models used in our codes. Thereafter, a scheme of radioactive waste burning system is studied. (authors). 4 refs., 7 figs., 1 tab