EFFICIENCY AND RELIABILITY IN DEEP-PENETRATION MONTE-CARLO CALCULATIONS

In this paper the effect of the weight-window splitting/roulette-technique and of the biasing method on the efficiency and a newly-defined quality characteristic called "reliability" has been studied by Monte-Carlo simulations of a monoenergetic shielding model. Both methods have utilized the same type of importance functions. It is observed that efficiency and reliability show qualitatively similar dependences on the calculational schemes, though quantitative differences are evident. Concerning the optimum effect of the weight-window method, the hypothetical concept of using the adjoint flux in determining the weight-window has been supported with respect to efficiency as well as reliability. The direct comparison of the biasing and splitting method in utilizing information on certain adjoint functions shows the great superiority of the biasing method.