The Physical Theory of Neutron Chain Reactors

absorption cross-section angular approximation assumed asymptotic atoms average Boltzmann equation boundary conditions calculation cent chain reactor chapter cm² coefficient compound nucleus computed control rod corresponding criticality factor decrease delayed neutrons denoted depends diffusion equation E. P. Wigner escape probability expression extrapolation distance fast effect fast neutrons finite fission neutrons fission products fuel element function given gives grad graphite Hence increase infinite kernel lattice lethargy mass material buckling mean free path measured medium method moderator multiplication factor natural uranium natural-uranium neutron density neutron distribution neutron energy neutron flux neutron temperature neutrons absorbed nuclear number of neutrons obtained P₁ particles Phys PICG quantity radius ratio reaction reflector region resonance absorption resonance escape resonance integral result scattering cross-section slowing-down solution spectrum spherical harmonics surface Table temperature term thermal neutrons thermal reactors thermal utilization tion trons unit width zero Σα