research
Startup transients in accelerator driven systems using cinesp-ads code
- Publication date
- Publisher
- IEN
Abstract
Accelerator Driven Systems (ADS) are subcritical nuclear reactor cores driven by spallation neutron source.
These spallation neutrons are provided from the bombardment of a liquid metal flowing in a central region of
the core, by a proton beam coming from a linear accelerator. Since neutron source dominates the neutronic of
the ADS, its control usually is not related to the delayed neutron fractions as in the critical systems. In this way,
ADS kinetics diverges from the former ones. This work presents some results of transients in ADS. Since ADS
is to work in a pulsed regime, with time duration of pulse, a parametric result is showed to point out that
different pulse durations should be studied in conjunction with pulse intensity, to maintain the ADS power
stable. In addition, before generating these results, some transients were used to validate the CINESP-ADS
code. It solves numerically the kinetic equations based on the multigroup diffusion theory, in One- or Twodimensional,
in the Cartesian or Cylindrical geometries, and for any energy and delayed neutron groups. Threedimensional
simulation is possible using a reactor transversal buckling. The numerical solution is obtained via
finite differences for the spatial discretization, using the so-called box integration, and with the use of
Alternating Direction Explicit (ADE) methods, for the time discretization. The code application to some
transients due to source neutron variations demonstrates its efficiency and accuracy, when compared with
analytical techniques, such as one that uses expansion in series of Helmholtz eigenfunctions