The neutron streaming correction method in the homogenization of pebble-bed HTGR reflector

In pebble bed high temperature gas-cooled reactors (HTGRs), the graphite reflector generally contains void regions including control rod channels, absorber ball channels and coolant channels. However, reactor physics design of HTGR based on deterministic codes usually models the reactor by two dimensional r-z coordinate system, which means the regions must be homogenized in azimuthal direction. PANGU is a modern computer code for pebble-bed HTGR physics analyses and fuel cycle simulations. This paper demonstrates a new method, for the homogenization of the reflector, implemented in PANGU code. The new method, taking into account the neutron streaming effect, can improve the accuracy of neutronics calculation. (author)