In this work, the average current nodal expansion method was developed for
the time-dependent neutronic simulation of transients in a nuclear
reactor's core. For this purpose, an adopted iterative algorithm was
proposed for solving the 3-D time-dependent neutron diffusion equation. In
the average current nodal expansion method, the domain of the reactor core
can be modeled by coarse meshes for neutronic calculation associated with
reasonable precision of results. The discretization of time differential
terms in the time-dependent equations was fulfilled, according to the
implicit scheme. The proposed strategy was implemented in some kinetic
problems including an infinite slab reactor, TWIGL 2-D seed-blanket reactor,
and 3-D LMW LWR. At first, the steady-state solution was carried out for
each test case, and then, the dynamic neutronic calculation was performed
during the time for a specified transient scenario. Obtained results of
static and dynamic solutions were verified in comparison with well-known
references. Results can indicate the ability of the developed calculator to
simulate transients in a nuclear reactor's core.
Second order of average current nodal expansion method for the neutron noise simulation
