A fast Jacobian-Free Newton-Krylov iterative solver for eigenvalue search problems in the reactor physics

Document Type: Original Article

Author

Faculty of Engineering‎, ‎Shahid Beheshti University‎, ‎G.C‎, ‎P.O‎. ‎Box‎: ‎1983963113‎, ‎Tehran‎, ‎Iran

Abstract

‎The Jacobian-Free Newton-Krylov (JFNK) method has been widely used in solving nonlinear equations arising in many applications‎. ‎In this paper‎, ‎the JFNK solver is examined as an alternative to the traditional power iteration method for calculation of the fundamental eigenmode in reactor analysis based on even-parity neutron transport theory‎. ‎Since the Jacobian is not formed the only extra storage required is associated with the workspace of the Krylov solver used at every Newton step‎. ‎A new nonlinear function is developed for the even-parity neutron transport equation utilized to solve the eigenvalue problem using the JFNK‎. ‎This Newton-based method is compared with the standard iterative power method for a number of multi-groups‎, ‎one and two dimensional neutron transport benchmarks‎. ‎The results show that the proposed algorithm generally ends with fewer iterations and shorter run times than those of the traditional power method‎.

Highlights

  • A new nonlinear function has been developed for solving the eigenvalue problem‎.
  • The JFNK approximation casts as an accelerated iterative approach‎.
  • Numerical results were generated using FEMPT code‎.
  • The results indicate that the JFNK method can converge faster than the standard procedure‎.

Keywords