An efficient personal computer-based threedimensional reactor core model TRIDA is developed to simulate the dynamics of the reactor for simulator applications. A fast running matrix factorization technique is used to solve the coupled nodal kinetics equations. Calculations for several off-normal and highly asymmetric transients are performed, and some of the results are compared with those of the Arkansas Nuclear One Unit 2 Final Safety Analysis Report. In addition, the computation time of the matrix factorization technique is compared with those of the Gaussian elimination and Jacobi iterative techniques. Results of comparisons are also given.