Using Monte Carlo Method to calculate the neutron distribution within fuel assembly for PWR

Considering fuel assembly for PWR, it is possessed of dense lattice, complex geometry and strong absorption of neutron. To calculate the neutron distribution, in this case, the rather big errors would occur if the diffusion theory were used. However, Monte Carlo Method is suitable for dealing with the problem. By adopting the physics mode given in this thesis, the accuracy of computed results is within experimental errors if the number of computed neutrons is large enough. The precision of physics mode given in this thesis has been proved by lots of physics experiments done in many countries in the world, and it has been adopted for physics design in China. In treating the scattering collision in thermal energy region, anisotropy scatter and the effect of chemical bond between moleculaes are both considered. For the scattering collision in high energy region, inelastic scatter is also taken into account