Direct Discrete Method (DDM) and its Application to Neutron Transport Problems


Department of Mechanical Engineering,Sharif University of Technology


The objective of this paper is to introduce a new direct method for neutronic calculations.
This method, called Direct Discrete Method (DDM), is simpler than the Neutron Transport
Equation and more compatible with the physical meanings of the problem. The method, based
on the physics of the problem, initially runs through meshing of the desired geometry. Next,
the balance equation for each mesh interval is written. Considering the connection between the
mesh intervals, the nal discrete equation series are directly obtained without the need to rst
pass through the set-up of the neutron transport di erential equation. In this paper, a single and
multigroup neutron transport discrete equation has been produced for a cylindrical shape fuel
element with and without the associated clad and the coolant regions, each with two di erent
external boundary conditions. The validity of the results from this new method are tested against
the results obtained by the MCNP-4B and the ANISN codes.