Abstract: Traditional volume rendering was difficult to adapt to the needs of large-scale numerical reactors visualization because of the global pre-meshing strategy for solid geometries and uniform ray-sampling rendering algorithm. In this paper, an efficient and high quality visualization framework was introduced for the solid-based reactor datasets. A novel rendering pipeline was presented for on-demand solid-meshing that utilizes the characteristic of high repeatability of reactor models. A surface-based CPU ray-casting rendering algorithm of unstructured mesh was proposed based on the pipeline for accelerated rendering of the large number of homogeneous solids within reactor models. The non-photorealistic rendering techniques coupled within the framework were also implemented for generating more perceptually effective visualization of reactor datasets. Experimental results shows that this framework can be used to scalably handle large-scale reactor datasets, and allows clearly convey the model structures and materials interfaces.