PP_{o} 2^{t /DT}k_{eff}1k_{eff}1.002511.00250.00249k/k¯effeff0.00700.002490.10 sec^{1} 0.0024918.1 secREACTOR KINETICSDOE-HDBK-1019/2-93Reactor Theory (Reactor Operations)NP-04Rev. 0Page 18Doubling time (DT) = (ln 2)where:= stable reactor periodln 2= natural logarithm of 2When the doubling time is known, the power level change from P is given by the followingoequation.(4-12)where:t= time interval of transientDT= doubling timeThe following example problems reinforce the concepts of period and startup rate.Example 1:A reactor has a of 0.10 sec and an effective delayed neutron fraction of 0.0070. Ifeff-1k is equal to 1.0025, what is the stable reactor period and the SUR?effSolution:Step 1:First solve for reactivity using Equation (3-5).Step 2:Use this value of reactivity in Equation (4-9) to calculate reactor period.