A Hybrid Multigroup/Continuous-Energy Monte Carlo Method for Solving the Boltzmann-Fokker-Planck Equation

Radiation Shielding Analysis of Niowave’s Uranium Target Assembly 2 (UTA-2) Facility for Molybdenum-99 Production

“…𝜇 s = photon scattering coefficient [cm -1 ] 𝑅 pf = Photon gain rate term from photofission reactions [cm -3 s -1 eV -1 ] 𝑄 p = photon source distribution (includes bremsstrahlung and neutron fission gammas) [cm -3 s -1 sr -1 eV -1 ] 𝜓 n = neutron angular flux [cm -2 s -1 sr -1 eV -1 ] 𝛴 t = total macroscopic neutron cross section [cm -1 ] 𝛴 s = scattering macroscopic neutron cross section [cm -1 ] 𝜒 = Neutron fission energy spectrum 𝜈 n = average number of neutrons produced per fission 𝛴 f = fission macroscopic neutron cross section [cm -1 ] 𝜙 n = Neutron scalar flux [cm -2 s -1 eV -1 ] 𝑄 n = neutron source distribution (includes photoneutrons) [cm -3 s -1 sr -1 eV -1 ]. (Morel 1996, Wang 2018, Duderstadt and Hamilton 1976 The photofission term was extrapolated to be similar to a neutron fission term. The boundary conditions for the multiparticle (electron-photon-neutron) transport problem solved by MCNP are vacuum 𝜓 e 𝑟,𝐸,Ω = 𝐿 𝑟,Ω = 𝜓 n 𝑟,𝐸,Ω = 0 for Ω • e s < 0 for all points r s on boundary surface S B .…”

Modeling Isotope Kinetics in a Circulating Fuel System: a Case Study of the MBIR Reactor Loop

“…To generate cross-section tables for electron/photon transport problems that will use the multigroup Boltzmann-Fokker-Planck algorithm, 44 the CEPXS 47 code developed by Sandia National Laboratory and available from RSICC can be used. The CEPXS manuals describe the algorithms and physics database upon which the code is based; the physics package is essentially the same as ITS version 2.1.…”

Numerical computation of discrete differential scattering cross sections for Monte Carlo charged particle transport

“…That work makes use of recursion relationships described by Morel (Morel, 1979) to generate modified moments of the weight function defined by the selected cross section model. These modified moments are then used as inputs for the algorithm developed by Sloan (1983), and extended in work by Morel et al (1996), for generating discrete cross section values.…”