The time eigenvalue spectrum for nuclear reactors in multi-group diffusion theory

  • S. Dulla
  • P. Ravetto
  • P. SaraccoEmail author
Regular Article


We develop a fully analytical study of the spectrum of the neutron diffusion operator both for spatially homogeneous and reflected reactors in a multi-group energy model. We illustrate and discuss the results of the analysis of the time spectrum of the diffusion operator, to highlight some general properties of the neutronic evolution in a multiplying system. Various new results are presented, particularly regarding the possible existence of complex time eigenvalues, the appearance of a continuum part of the spectrum and the orthogonality properties of the eigenfunctions in the case of an infinite reflector.


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Copyright information

© Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Politecnico di Torino, Dipartimento EnergiaTorinoItaly
  2. 2.INFN, Sezione di TorinoTorinoItaly
  3. 3.INFN, Sezione di GenovaGenovaItaly
  4. 4.Centro FermiRomaItaly

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