Towards automatic CAD defeaturing for fusion neutronics

A typical neutronics simulation process may involve the conversion of a detailed CAD model into a modified analysis model. This conversion process almost always requires prior defeaturing or modification of the detailed model’s geometry, whether it is for neutronics simulation software that uses constructive solid geometry or faceted geometry. Some simplification guidelines have been suggested. For example, conversion from a neutral CAD format (typical of design software) to constructive solid geometry requires the removal of elements
such as higher-order surfaces and splines. In the case of conversion into faceted geometry, the geometry does not contain surface overlaps. A concern driving the need for automation is how this can be executed efficiently for large, complex CAD models. This is because the defeaturing process is typically done manually and usually relies on the experience and judgement of practitioners. Also, this iterative process is one that often necessitates collaboration between the designer and analyst to produce models of appropriate complexity and accuracy suitable for the task. The presentation will outline the key challenges in automating defeaturing, describe geometric characteristics desirable for neutronics modelling, and suggest techniques that will help deliver the goal of creating an automated CAD defeaturing process. This work will be of interest to those involved with neutronics modelling who receive CAD models directly from the designer and are
motivated to improve their practice. It will also benefit researchers who are looking at ways to streamline neutronics simulation procedures.