No abstract available

[en] The axial propagation of a fission burn-up wave in a cylinder, consisting originally only of fertile material like U-238 or Th-232, is described. To solve the corresponding (non-linear) wave equation a new 'partial separation technique' is used. The results show that, indeed, an axial soliton-solution exists and that the burn-up of the autocatalytically-driven wave phenomenon is flat with respect to the cross-section of the cylinder. (orig.)

[en] Using the method of ''affine solutions'' three interesting phenomena in a CANDLE Burn-Up strategy were studied and were cast analytically into mathematical formulae: (a) the problem of two burn-up waves one behind the other (''enslavement principle'') (b) the problem of the frontal collision of two burn-up waves (''Scattering''), and (c) the problem of two identical burn-wave twins moving apart from each other after central ignition (''Breathing Out Phenomenon''). To the knowledge of the author this is the first time where such affine problems of the CANDLE Burn-Up wave physics were solved. (orig.)

No abstract available

[en] The article outlines a few important aspects of an energy strategy with hydrogen as an environmentally harmless secondary energy carrier. Following a compilation of the particular characteristics and advantages of hydrogen, the H₂ production by electrolysis using electrical energy from nuclear power plants and by thermolysis using nuclear process heat from high-temperature nuclear reactors, a few methods of H₂ storage and use, as well as the role of hydrogen in the future energy and raw materials economy are mentioned. (GG/LH)

[en] Parallel to the energy fluxes the entropy fluxes of decentralized hot-water systems based on solar collectors coupled with an electrical auxiliary heating installation are also deduced. As an important result the fact emerges that this kind of solar energy has to remain very restricted, not only for quantitative-energetic reasons, but also for entropy ones, and that a solar hot-water system will always have to rely on an energy system of low entropy. In contrast to this, the provision of heat for space heating sector with the help of the 'nuclear short-distance concept', which practically does not need any external energy, is not subject to these restrictions. This concept is introduced briefly, as well as the heat prices which presumably can be achieved by it. Concluding comments summarize the reasons once again that speak against the installation of a decentralized solar heat supply system. (orig.)

[en] Energy costs and interest rates of Nuclear Power Plants are considered, and conclusions drawn as to whether nuclear power plants are energy sources or energy sinks. (U.K.)

No abstract available

[en] The preignition probability for a sigmoidal reactivity input in nuclear explosive devices (NEDs) with a strong inherent neutron source strength (i.e. using reactor grade plutonium) is treated comprehensively. The cumulative preignition probability, its probability density as well as the most probable time for preignition during the compression phase are presented in a closed analytical form. This general formalism can be used to calculate the preignition probability for any metallic core composition (either Pu or U or hybrid) possessing an inherently strong or weak background of neutrons. (orig.)

[en] The complete analytical integration of the non-linear Neutron Flux Wave Equation (NFWE) for an optically thick absorber plate can be determined by the transformation Φ(ξ, τ)=G/(1+G), where G obeys the linear heat equation G_τ=G_ξξ. The backward transformation of a linear superposition in G delivers the complete integration. Aside from Burger's equation this is another example that Cole-Hopf like transformation procedures can be instrumental to solve nonlinear partial differential equations. (orig.)