MCNP surface source and CASTOR simulations

Surface sources have been successfully applied to make simulation of casks for storage and transport of radioactive material (CASTORs) in our earlier work. The application of surface sources can save simulation time and improve calculation efficiency. Normally a simulation involves many CASTORs, which make the calculation very time consuming. In our work, parallel computing has been used to accelerate the calculations. Normally the parallel computing runs on a distributed cluster system, which needs communications between different processes through message passing interface (MPI). To obtain good results, the size of a surface source for a CASTOR is usually several or tens of GB. In order to perform such a simulation, each process should be able to read the surface source file. In some cases, the date transfer of the surface source file could take a lot of time. In this work, surface sources were tested with different geometry and number of processors in parallel computing. By comparing performances in different conditions, the application of surface sources is discussed. (orig.)