AN core analysis

Several alternative approximations of neutron transport have been proposed in years to move around the known limitations imposed by neutron diffusion in the modeling of nuclear cores. However, only a few complied with the industrial requirements of fast numerical computation, concentrating more on physical accuracy. In this work, the AN transport methodology is discussed with particular interest in core performance calculations. The implementation of the methodology in full core codes is discussed with particular attention to numerical issues and to the integration within the entire simulation process. Finally, first results from core studies in AN transport are analyzed in detail and compared to standard results of neutron diffusion. First tests on a standard PWR core shows corrections of about 1-2% on flux peaks caused by AN, with a few hundreds pcm changes on the neutron multiplication factor. It is important to notice that most of the correction comes already from lower orders AN