SELECTION OF FEEDBACK PARAMETER VALUES IN PREPARATION OF LOW-GROUP CONSTANT LIBRARIES FOR VARIOUS DYNAMIC CONDITIONS
24th Symposium of AER on VVER Reactor Physics and Reactor Safety (2014, Sochi, Russia)
Reactor dynamics and safety analysis
Abstract
SELECTION OF FEEDBACK PARAMETER VALUES IN PREPARATION OF LOW-GROUP CONSTANT LIBRARIES FOR VARIOUS DYNAMIC CONDITIONS
Bryukhin V.V., Uvakin М.А., Kurakin K.Yu. OKB “GIDROPRESS”
ABSTRACT
The thermohydraulic computer code KORSAR/GP used for coupled neutronics and thermohydraulic calculations belongs to the best estimation code and is intended for simulation of normal operating conditions and accidents at reactor plants with VVER. The neutron kinetics module KARTA with the constant provision prepared by the software package SAPFIR_95&RC_VVER is used for calculation of core neutron kinetics of the VVER-type reactors in 3-D approximation in a set of KORSAR/GP.
Macroconstants of the reflector or core element depend on the values included into it, on thermal-physical parameters – feedback parameters (FBP). Dependence of the feedback parameter macroconstants in the module of spatial neutron kinetics is implemented based on multidimensional tables. Multidimensional table can be interpreted for each macroconstant as determination of its values in the parametric mesh knot points. Macroconstants for arbitrary values of feedback parameters are obtained by approximation of knot values of the macroconstants in the form of polynomials.
The present paper deals with the consideration of analysis of selection of quantity and values of the feedback parameter mesh knot points in preparation of low-group characteristic library. A method has been proposed for breakdown of the range of every possible values of feedback parameters into a sufficient quantity of intervals so that selection of any knot value of feedback parameter out of the range will not affect the results of neutronics characteristics when plotting the parametric mesh. Evaluation has been made for uncertainly of selection of the feedback parameter values on the results of safety parameters in simulation of various dynamic processes according to SP KORSAR/GP.