Nonlinear nodal diffusion theory solver incorporated into CANDU-PHWR neutronics code: SCAN

Nonlinear unified nodal diffusion theory solver is developed and incorporated into SCAN code, the CANDU-PHWR nuclear design analysis code. The effectiveness of the nonlinear unified nodal method (UNM) calculations is compared with that of the existing finite difference method calculations for the nuclear design parameters of Wolsong unit 3 CANDU reactor. It is shown that, though it is not so striking as in the light water reactors, the nonlinear UNM outperforms the finite difference method in prediction accuracy of the channel and the bundle power distribution at the expense of increased computer time. It is also shown that the two nodal computational options of the UNM, the nodal expansion method and the analytical nodal method, are very similar in prediction accuracy for the nuclear design parameters of the CANDU reactor. (author)