New computational methodology for large 3D neutron transport problems

We present a new computational methodology, based on 3D characteristics method, dedicated to solve very large 3D problems without spatial homogenization. In order to eliminate the input/output problems occurring when solving these large problems, we set up a new computing scheme that requires more CPU resources than the usual one, based on sweeps over large tracking files. The huge capacity of storage needed in some problems and the related I/O queries needed by the characteristics solver are replaced by on-the-fly recalculation of tracks at each iteration step. Using this technique, large 3D problems are no longer I/O-bound, and distributed CPU resources can be efficiently used. (authors)