CALCULATIONAL METHOD OF ONE-GROUP NUCLEAR CONSTANTS IN NUCLEAR EQUILIBRIUM STATE

摘要

The conventional one-group nuclear data sets for the nuclear equilibrium state are not consistent with the equilibrium nuclide densities, and mar contain considerable errors. An equilibrium cell iterative calculation system (ECICS) has been developed to obtain the consistent neutron spectrum, one-group constant set and nuclide number densities which characterize the nuclear equilibrium state. This system employs an iterative calculation scheme combining cell neutron transport calculation and equilibrium nuclide density calculation. In ECICS, a two-step iterative method and transferred data manipulation are contrived to ensure and accelerate the convergence. Some results obtained by ECICS are compared with the results obtained with cross section sets for fresh fuel conditions to show the efficiency of ECICS. [References: 12]