OPTIMIZATION OF NEXT-EVENT ESTIMATION PROBABILITY IN MONTE CARLO SHIELDING CALCULATIONS.

In Monte Carlo radiation transport calculations with point detectors, the next-event estimation is employed to estimate the response to each detector from all collision sites. The method described in this paper was tested on a spent fuel shipping cask problem. The doses at six axial detectors were calculated with and without the optimized estimation probabilities. Discrete ordinates results were also performed to verify Monte Carlo results. Results indicate that the optimized next-event estimation probabilities improve the efficiency of the Monte Carlo calculation by more than a factor of 4.