Solving reactor problems to determine the multiplication: A new method of accelerating outer iterations

A new cyclic iterative method with variable parameters is proposed for accelerating the outer iterations in a process used to calculate $K_{\text{эфф}}$ in multigroup problems. The method is based on the use of special extremal polynomials that are distinct from Chebyshev polynomials and take into account the specific nature of the problem. To accelerate the convergence with respect to $K_{\text{эфф}}$, the use of three orthogonal functionals is proposed. Their values simultaneously determine the three maximal eigenvalues. The proposed method was incorporated in the software for neutron-physics calculations for WWER reactors.