Neutron kinetics of the Chernobyl accident

The classical reactor kinetic equations with six groups of delayed neutrons are not solved analytically. Here they are solved numerically with MATLAB and applied to the Chernobyl accident. The results are presented graphically. Now, 20 years after the accident it is important for today's and tomorrow's generations of nuclear engineers to learn not to design reactors with runaway characteristics which can cause an avalanche like power excursion. The Chernobyl type of reactor has a positive void coefficient, which means that when a part of the water is replaced by steam the power will increase. At the Chernobyl experiment the steam content in the coolant channels increased suddenly causing a catastrophic power excursion. The presented analyses gives details about the importance of the magnitude of the void coefficient. Also the delayed neutrons behaviour is described. (orig.)