DORTOREST. A new coupled transport/burn-up code system

The precise pin-wise determination of the nuclide inventory and neutronic properties of irradiated fuel assemblies is an important task in various areas of nuclear technology such as criticality safety of spent fuel or the generation of cross section input for full core reactor calculations. Modern code systems for this purpose typically couple a two- or three-dimensional transport solver to a depletion code in an iterative fashion. The employed transport code can be either a Monte-Carlo code or a deterministic solver. The former has major advantages concerning the flexibility and accuracy in modeling the fuel assembly geometry, the latter usually offers faster convergence and higher accuracy when a very high resolution in space and energy is required; this is especially important, when one is interested in the extraction of spatially homogenized few group cross-sections for full core reactor physics calculations. Based on the GRS-developed KENOREST the new coupled deterministic burn-up code DORTOREST is presented here. A description of the main properties is given and first application results are presented, including the participation in the OECD/NEA Expert Group on Burn-up Credit benchmark on reactivity worth calculations. (orig.)