1. More on One-Speed Diffusion
HW 20
Show that for a critical homogeneous reactor
Infinite Bare Slab Reactor (one-speed diffusion) z 
Vacuum beyond.
Return current = 0.
d = linear extrapolation distance
= 0.71 tr (for plane surfaces)
= 2.13 D.
Reactor x
a/2 a
a0/2 d d
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).

2. More on One-Speed Diffusion
HW 21
For the infinite slab Show that the general solution
with BC’s
Flux is symmetric about the origin. 
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).

3. More on One-Speed Diffusion
HW 21 (continued)
Fundamental mode, the only mode significant in critical reactors.
For a critical reactor, the geometrical buckling is equal to the material buckling.
To achieve criticality
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).

4. More on One-Speed Diffusion
To achieve criticality
But criticality at what power level??
0 can not be determined by the geometry alone.
Do it.
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).

5. More on One-Speed Diffusion
Spherical Bare Reactor (one-speed diffusion)
Cube
Sphere
Minimum leakage  minimum fuel to achieve criticality. 
HW 22 r 
Reactor
Continue! r0
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).

6. More on One-Speed Diffusion
HW 23
Infinite planer source in an infinite medium.  
HW 24 ?
Infinite planer source in a finite medium. x
a/2 a
a0/2
Source
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).

7. More on One-Speed Diffusion
Infinite planer source in a multi-region medium.
Infinite
Finite
Infinite 
Project 2
Nuclear Reactor Theory, JU, Second Semester, (Saed Dababneh).