[en] An algorithm is presented for merging the results of neutron ray-tracing in simpler geometries, into which a given target geometry has been previously decomposed. The algorithm automatically numbers regions in the target geometry and displays information about their origin in terms of region numbers assigned to the simpler geometries. Information about the organisation of the program utilising the algorithm is also given. (author)

[en] The discrete eigenvalue problem associated with the one-speed azimuthal Fourier harmonics in plane geometry is discussed. An explicit expression, well-suited to numerical evaluation, is given for the dispersion function, and the reality and maximum number of discrete eigenvalues are demonstrated. From numerical examples, it is found that quite often there are no discrete eigenvalues, particularly for the higher harmonics

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[en] The index of the eigenvalue of the monoenergetic neutron transport operator is studied under the assumptions of homogeneity and boundedness of the medium and of isotropy of scattering. It is shown that all isolated real eigenvalues are with index one. In addition, the authors show that there is no nonreal eigenvalues in (λ C | Re λ > - Σ). 8 refs

[en] In this paper, we will address the problem of the transport of neutron in these double-random media. The key point in our approach lies in the assumption that random treatment is valid to this types of problems

[en] The backward formulation of problems in neutron transport is considered. Boundary conditions are developed from the adjoint system which in turn is rigorously obtained from a variational principle. The variational principle is derived by constraining the flux with the forward transport equation and affiliated boundary/initial conditions, avoiding physically motivated Importance arguments. Extremising the constrained functional yields both the forward and adjoint equations as well as boundary/initial conditions as the Euler Lagrange system. The backward formulation provides a means of developing exact equations for the scalar flux and emergent current as well as internal distributions such as the slowing down density. (author)

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No abstract available

[en] Multiple collision solutions of the time-, space-, and angledependent neutron transport equation in slab geometry are given. Two different monodirectional sources have been used: Firstly, a delta(t)-shaped pulse of neutrons (delta(t): Dirac delta distribution) impinging on the slab at time t=0, secondly, a 'rectangular' source, emitting neutrons for a time interval Δt, describing a somewhat more realistic situation. Detailed results up to collision order three are discussed and exhibited in several figures. Interestingly the 'scalar' flux of one times scattered neutrons for the slab problem turns out to be independent of space in the region influenced by the slab boundaries. (Author)

[en] It is proven that the monoenergetic neutron transport operator in the case of a spherically symmetric, isotropically scattering sphere with a cavity in a large body has infinitely many complex time eigenvalues. 15 refs