Formulation of mathematical adjoint equation from a higher order nodal expansion method
- Seoul National Univ., Seoul (Korea, Republic of)
The purpose of this paper is to present a new formulation for determining mathematical adjoint flux from a higher order nodal expansion method (NEM). In the higher order NEM in which higher order polynomial expansion is assumed for the transverse integrated one-dimensional flux, the nodal forward equations appear as inhomogeneous eigenvalue equations because of terms involving higher order expansion coefficients. This poses a difficulty of defining mathematical nodal adjoint equations. In order to get around this difficulty, the weighted residual method equations designed for determining higher order expansion coefficients are utilized to eliminate the higher order expansion coefficients from the nodal forward equations and to cast the resulting nodal forward equations into formally homogeneous eigenvalue equations. The mathematical adjoint equations of the higher order NEM are then formulated by transposing the coefficient matrix of the nodal forward equations. The new formulation is verified by comparing nodal adjoint flux computations with fine-mesh VENTURE computation for IAEA PWR benchmark problem and also by comparing the first-order perturbation computations for the local perturbation effects on core reactivity of IAEA PWR and Yonggwang Unit 2 PWR with the forward eigenvalue computations for the perturbed and the unperturbed cores.
- OSTI ID:
- 459259
- Report Number(s):
- CONF-950420--
- Country of Publication:
- United States
- Language:
- English
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