A Simplified 2-d Multi-cell Model for Radial Reflector Modelling in PT-SCWR

Abstract

Using a multi-cell methodology to model the radial reflector in a PT-SCWR is essential to get an accurate power distribution. On the other hand, solving the transport equation for such a multi-cell calculation is very heavy computationally, so choosing this multi-cell as small as possible while preserving the accuracy is very important. In this study a 6x6 multi-cell model has been used to get a reference full-core model. It was found that the fuel cell which is in contact with the side or corner cells is different from the cells in an infinite lattice. A simplified multi-cell model consisting of 3x3 instead of 6x6 cells has been proposed. In this case, an albedo equal to 0.85 was found to give the closest results to the reference large 6x6 multi-cell. It was found that the proposed model can be used with fuel has different fissile content and with fuel burnup.