HELIOS: Application for criticality limits assessment
21st Symposium of AER on VVER Reactor Physics and Reactor Safety (2011, Dresden, Germany)
Spectral and core calculations
Abstract
In the early years, after the discovery of fission, the criticality safety assessment and the
established safety limits, have been mainly based on direct experiments. Later, following the
advances in the theory, computational methods and computer hardware, theoretical methods
have been elaborated to the level to become reliable assessment tools. The computer codes
started replacing the experiments, while the experimental data became a valuable validation
source for their models.
An application of the 2D transport theory code HELIOS (1,2) for assessment of criticality
limits is presented in this paper. The effect of the enrichment, the system dimensions, H/U5
ration and different reflectors were studied in heterogeneous and homogenized systems.
Comparisons with published experimental data and evaluated safety limits are made here to
demonstrate the range of HELIOS applicability and limitations.