UNCERTAINTY ANALSIS OF FUEL LATTICE PHYSICS USING CASMO-4 WITH JENDL-4.0 COVARIANCE DATA

摘要

Uncertainty analyses with respect to the nuclear covariance data are performed for BWR and PWR fuel lattices specified in the framework of UAM-LWR Benchmark Phase Ⅰ. In order to evaluate the uncertainties of fuel lattice calculations due to the nuclear data uncertainties, the uncertainty analysis system using the Monte Carlo stochastic sampling method has been developed based on the lattice physics code CASMO-4. This system uses the JENDL-4.0, and it calculates the propagation of the nuclear data uncertainties represented by the nuclear covariance data into uncertainties of interest parameters. In the present study, the uncertainties of interest parameters due to nuclear data uncertainties such as neutron multiplication factors, pin power distributions and homogenized parameters in assembly models have been qualified. Then it was found that the uncertainty of the neutron multiplication factor due to nuclear data uncertainties in each model was less than 1 % dk/k. Furthermore, the uncertainties of pin power distribution in assembly models due to nuclear data uncertainties were up to approximately 0.5 %.