The Laplace transform method for solving the burnup equation with external feed.

• The Laplace transform method is applied in burnup calculations with external feed. • CRAM and QRAM are extended to treat external feed. • The external feed term can have polynomial, exponentially decaying and even more complicated form of time-dependence. • The new method is equivalent to the augmented matrix method, but more flexible and easy-to-implement. Burnup calculation is an essential topic in reactor physics analysis. And in some advanced reactors, the fuel material is continously fed into the reactor core, so that external feed must be introduced into the burnup calculations. In this work, the Laplace transform method for solving the burnup equation with external feed is presented. Based on the Laplace transform method, the Quadrature-based Rational Approximation Method (QRAM) and the Chebyshev Rational Approximation Method (CRAM) have been extended to handle the burnup equation with either constant or time-dependent external feed term. Several numerical test cases are carried out to demonstrate the correctness and high-performance of the proposed method. [ABSTRACT FROM AUTHOR]