SYSTEM FOR MODELLING THERMAL PROPERTIES OF REACTOR VESSELS

A method and system for determining the temperature response of a body to input power supplied to a plurality of heater units (8) disposed for heating the body (2), utilizing apparatus composed of computer means (40-46) having a manual data input device (44), a first memory unit for storing data representative of the thermal characteristics which determine the relation between the input power supplied to each heater unit (8) and the resulting temperature of the body (2), a calculation device connected for calculating the temperature of the body (2) during successive time steps on the basis of heater input power data supplied via the manual data input device (44) and the stored data, and display and recording devices (42,46) connected for displaying and recording the heater input power data and calculated temperature of the body (2) during each time step. The method is carried out by: supplying (26), via the manual data input device (44), selected heater input values at the start of each time step; operating (30) the calculation device for calculating, during each time step, the temperature of the body (2) in accordance with the temperature calculated during the previous time step and the heater input values supplied during the present time step; and operating (34) the display and recording devices for displaying and recording the temperature calculated during each time step.