Study of non-intrusive model order reduction of neutron transport problems

•An efficient non-intrusive method is proposed to solve the neutron diffusion problem with movement of control rods.•Three to four orders of speedup is achieved for typical pressurized water reactor cores.•The method can be adapted to other types of problems. Model order reduction is one important technique to speed up the solution of large-scale problems. Two model order reduction techniques, i.e., the proper orthogonal decomposition with interpolation and the Gaussian process regression, are investigated to compute the neutron flux and the effective multiplication factor. Two reduced order models are constructed and it is shown that a speedup of 3 ~ 4 orders of magnitude is achieved with guaranteed accuracy. The Gaussian process regression model can predict the mean value of keff and more importantly, the uncertainty of the predicted value can be analyzed as well.