Neutron transport

Table of contents

1 Reed’s problem

Reed’s problem (William H. Reed (1971) New Difference Schemes for the Neutron Transport Equation, Nuclear Science and Engineering, 46:2, 309-314, DOI: 10.13182/NSE46-309) is a common test problem for transport codes. It is comprised of heterogeneous materials with strong absorber, vacuum, and scattering regions. These regions are valuable to testing different aspects of numerical discretizations.

Geometry of the 1D Reed’s problem (1971)
PROBLEM neutron_transport DIM 1 GROUPS 1 SN $1
READ_MESH reed.msh
MATERIAL source1       S1=50 Sigma_t1=50 Sigma_s1.1=0
MATERIAL absorber      S1=0  Sigma_t1=5  Sigma_s1.1=0
MATERIAL void          S1=0  Sigma_t1=0  Sigma_s1.1=0
MATERIAL source2       S1=1  Sigma_t1=1  Sigma_s1.1=0.9
MATERIAL reflector     S1=0  Sigma_t1=1  Sigma_s1.1=0.9

BC left  mirror
BC right vacuum


$ gmsh -1 reed.geo
$ [...]
$ for n in 2 4 6 8; do feenox reed.fee ${n} | sort -g > reed-s${n}.csv; done

The solutions obtained in FeenoX with S_2, S_4, S_6 and S_8 are plotted and compared against and independent solution from

Solution of the Reed’s problem