P
Po 10SUR (t)
P
Po et /
P
Po 10SUR (t)
P
Po
et/
10SUR (t)
et (sec)/
e2.303 SUR (t (min))
t (sec)
2.303 SUR(t (min))
60
2.303 SUR
SUR
26.06
Reactor Theory (Reactor Operations)
DOE-HDBK-1019/2-93
REACTOR KINETICS
Rev. 0
NP-04
Page 17
Reactor Startup Rate (SUR)
The reactor startup rate (SUR) is defined as the number of factors of ten that power changes
in 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 the
2.303
result yields the following.
(4-11)
Doubling Time
Sometimes it is useful to discuss the rate of change of reactor power in terms similar to those
used in radioactive decay calculations. Doubling or halving time are terms that relate to the
amount 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.
