Comparison of three acceleration techniques for the fixed source neutron transport calculation

In order to accelerate the convergence of the fixed source problems with multiplicative media in the neutronics analyses of subcrilical reactors or transient neutron transport calculations, three acceleration techniques are presented and compared in this paper, i.e rebalance method, k_siteration method and coarse mesh finite difference (CMFD) method. The rebalance method adopts a rebalance factor to bring the disappear and source terms in the neutron transport equation into balance. The k_siteration method introduced the source multiplication factor k_sto remove the dependence of the convergence rate on the subcriticality. The CMFD method employs the non-linear iteration to accelerate the convergence of neutron transport calculation using the solution of the low-order CMFD equation. The accelerator driven subcrilical reactor problem was calculated to compare the acceleration effects of the three acceleration techniques. The numerical results showed that the rebalance method and the k_siteration method achieved similar speedup performances and reduced the computation time by a factor of 8.6, the CMFD method achieved a much better performance and reduced the computation time by a factor of 23.2.