HELIOS2: simple procedutre for generating few group homogenized parameters for non-multiplying domain in hexagonal geometry
20th Symposium of AER on VVER Reactor Physics and Reactor Safety (2010, Hanasaari, Espoo, Finland)
Spectral and Core Calculations
Abstract
The recent nodal reactor theory has improved the nodal reactor analyses to the point
where accurate three-dimensional nodal methods can successfully replace the detailed pin-bypin calculations, provided adequate homogenized parameters are available. That has been the
driving force behind the continuing development of transport methods and lattice codes from
one side and homogenization techniques from the other. The introduction of heterogeneous
factors by Koebke (1984) in the Equivalence Theory followed by the General Equivalent
Theory and the definition of the discontinuity factors by Smith (1985), significantly improved
the results from homogenized nodal calculations at the time and basically made possible the
subsequent advances in the nodal methods and higher order homogenization and rehomogenization techniques.
The purpose of this paper is to demonstrate the applicability of HELIOS2 (3) and its post
processor ZENITH in a simple, analytical procedure to derive and study homogenization
parameters in a multi-assembly domain of fuel assemblies and non-multiplying assembly
area. The two-group homogenized parameters are generated in the multi-assembly transport
calculation by HELIOS and then used in one-dimensional, two-group homogeneous diffusion
problem solved in ZENITH. The procedure is used to generate discontinuity factors and
albedo matrices for non-multiplying domain and to verify their dependence on exposure and
calculation conditions.