PP_{o} 10^{SUR (t)}PP_{o} e^{t /}PP_{o}10^{SUR (t)}PP_{o}e^{t/}10^{SUR (t)}e^{t (sec)/}e^{2.303 SUR (t (min))}t (sec)2.303 SUR(t (min))602.303 SURSUR26.06Reactor Theory (Reactor Operations)DOE-HDBK-1019/2-93REACTOR KINETICSRev. 0NP-04Page 17ReactorStartupRate(SUR)The reactor startup rate (SUR) is defined as the number of factors of ten that power changesin one minute. The units of SUR are powers of ten per minute, or decades per minute (DPM).Equation (4-10) shows the relationship between reactor power and startup rate.(4-10)where: SUR= reactor startup rate (DPM)t= time during reactor transient (minutes)The relationship between reactor period and startup rate can be developed by considering Equations (4-6) and (4-10).and Changing the base of the exponential term on the right side to "e" (10 = e) and solving the2.303result yields the following.(4-11)DoublingTimeSometimes it is useful to discuss the rate of change of reactor power in terms similar to thoseused in radioactive decay calculations. Doubling or halving time are terms that relate to theamount of time it takes reactor power to double or be reduced to one-half the initial power level.If the stable reactor period is known, doubling time can be determined as follows.