Page 59 - Dynamics and Control of Nuclear Reactors

50 CHAPTER 4 Solutions of the point reactor kinetics equations

3.0E-2

2.0E-2

Right Hand Side, r −1.0E-2 0
1.0E-2

−2.0E-2

−3.0E-2
10 −1 10 0 10 1 10 2
(A) Period, T
0.01

0.005
Right Hand Side 0

−0.005

−0.01
−0.05 −0.04 −0.03 −0.02 −0.01 0 0.01 0.02 0.03 0.04 0.05
(B) Laplace parameter, s
FIG. 4.15
(A) Right hand side of the Inhour equation. The x-axis (period) uses logarithmic scale. (B)
Right hand side of the Inhour equation in the neighborhood of zero.

An alternate, frequently used, measure of reactivity is the “INHOUR”. It is defined as
the ratio of reactivity to the reactivity that would cause a stable period of one hour
(T ¼ 3600 s). That is
0 1
6
X β iðÞ
Λ + C
1 B
T @ 1 ÞA
i¼ + λ iðÞ
T
ρ ¼ 0 1 (4.20)
6
X β iðÞ
Λ + C
1 B
3600 @ 1 A
i¼1 + λ iðÞ
3600