A varied-order sweeping technique for the coarse mesh transport method in COMET

In this paper, a varied-order sweeping scheme was developed to improve the computational efficiency of the coarse mesh transport method in COMET. The new sweeping method updates the outgoing partial currents from a region based on the least possible assumptions about incoming current from the neighboring regions and consequently allows the information from a region to propagate to any other regions in a more efficient manner. The varied-order sweeping method has been tested for both neutron transport in 2D Candu reactor cores and photon transport in tissues. The comparisons have shown that the new method is more efficient and accurate than the original fixed-order sweeping scheme. (authors)