Adjustment and Application of Monte Carlo Neutron Calculation with Respect to Embrittlement Problems

Problems of the calculation of neutron fluences for reactor pressure vessel embrittlement determination were discussed. For the example of the calculation of neutron fluences of irradiated specimens within the Rheinsberg reactor (time period 1984-1988) it was shown, for which parts of the problem Monte Carlo methods can be very well applicated.
Some special measures were discussed, which are used for the own Monte Carlo codes (system TRAMO), especially the improved "Weight Window Method" and a proper calculation of the needed weights. Further the preparation of all needed data to take into account the history for each irradiation period was described and the influence of different neutron group data and the different handling of anisotropy of elastic scattering was considered.