Calculation of temperature distribution and effective temperature in high burnup fuel of WWER-1000

The problem of finding an effective temperature is highly important. This characteristic provides calculation of the power effect reactivity (PER), which defines safe and stable operation of nuclear reactor. The numerical experiment, which is considered on average and maximum heat load conditions, is put to find out changing of the effective temperature in the high burnup fuel of WWER-1000. In the course of the experiment mathematical statement of the problem is made, numerical solution of which is found with using the finite differences approximation of both control equations and border conditions. Also, the method of simple iteration is used for calculating temperature distributions, according to determination of the effective temperature. The linear approximation was obtained basing on effective and maximum temperatures depending on the burnup.

REDUCTION OF PLANE THERMOELASTICITY PROBLEM IN INHOMOGENEOUS STRIP TO INTEGRAL VOLTERRA TYPE EQUATION

We have developed a method for analytical solving of the plane thermoelasticity problem in terms of stresses for a strip, which is infinite with respect to width. To derive the governing equations, we have used a method of direct integration of differential equilibrium and compatibility equations. Reducing the governing equations to the integral Volterra type equation of the second kind, we have solved it in Fourier transforms by applying a method of simple iteration. Straipsnyje vystomas analizinio sprendinio metodas nehomogeninio strypo termoelastiškumo uždaviniui strypo itempimams rasti, kai strypo ilgis yra begalinis pločio atžvilgiu. Pagrindines lygtys išvedamos naudojant diferencialines pusiausvyros ir suderinamumo lygtis ir tiesiogini integravima. Suvedus pagrindines lygtis i antrojo tipo Volterra integraline lygti, naudojant Furje transformacija, ji sprendžiama paprastosios iteracijos metodu.