Problems of weight determination for the multigroup Monte Carlo code TRAMO for neutron flux calculation

In the Monte Carlo Code TRAMO for neutron flux calculation, the basic method for the reduction of statistical errors is the weight window method. Problems arise with the determination of the needed weights. It is first shown, by means of a simple example, that the general rule for obtaining these weights as inversely proportional to the importance is reasonable. Then methods for the calculation of these weights on the basis of a recursive Monte Carlo method are described which appear to be practicable for a wide range of applications. (author)