Development of repeat geometry function in reactor Monte Carlo code RMC

This paper describes repeat geometry structure function and its application to reactor analysis Monte Carlo codes. Common repeat structure output and implementation is introduced using MCNP and RMC (RMC is a reactor Monte Carlo code developed by REAL team in Department of Engineering Physics, Tsinghua University) as examples, and three speed-up methods for layer geometry structure and repeat geometry structure in RMC are presented. Examples of the Daya Bay reactor are calculated for comparison between MCNP and RMC, and results show that RMC speeds up by 3-9 times, compared with MCNP.