Analysis of Finite-Difference Approximation of Code TETCH-M in Performing Design Calculations of Parameters in the Primary and Secondary Circuits of VVER RP

In code package TETCH-M energy and coolant hydrodynamics equations, neutron kinetics equations and equations of heat conduction in metalwork and fuel rods are solved together. Processes described by these equations are characterized by different time constants and during calculation different degree of time and space discretization is required. The objective of the work was demonstration of stability of numerical schemes used in TETCH-M program and its modules, assessment of error of numerical solution for nodalization. Initial differential equations in partial derivative of the law of conservation of mass, energy and momentum are reduced to the system of usual differential equations on the basis of spatial approximation with the use of integro-interpolation method. Approximation was performed by integrating the initial differential equations in partial derivatives within the limits of each elemental volume of division by spatial coordinate. The usage of integro-interpolation method provides fulfilment of laws of conservation on computational mesh as a whole (conservatism of approximation method) and the second order of approximation by spatial coordinate.