Validity of FLUKA applied to calculation of fast neutron fluence in reactor pressure vessel

Based on the consideration of intellectual property, in order to find an alternative code of MCNP, the validity of FLUKA applied to the calculation of neutron fluence in reactor pressure vessel was studied by means of comparison of calculation results of the both codes. The secondary particle stack was manipulated by modifying and calling the user subroutines, and then the key problem of turning off the transportation of fission neutrons was solved. The results of FLUKA and MCNP code agree well with each other, with the relative deviation less than 5%. It is concluded that using FLUKA code in place of MCNP code is technically feasible.