Abstract: Point reactor dynamics equations with six groups of delayed neutrons havebeen computed via weighted residue method in which the δ function was taken asa weighting function, and the parabolic with or without exponential factor as atrial function respectively for an insertion of large or smaller teactivity. Thereactivity inserted into core can be varied with time, including insertion in formsof step function, polynomials up to second power and sine function. A thermal feedback of single flow channel model was added in. The thermalequations concerned were treated by use of a backward difference technique. A WRK code has been worked out, including implementation of an automaticselection of time span based on an input of error requirement and of an automaticchange between computation with large reactivity and that with smaller one.On the condition of power varied slowly and without feedback, the results arenot sensitive to the selection of values of time span. At last, the comparison of relevant results has shown that they agree quitewell.