Question

power plant needs to slow down the fission reactions in its nuclear reactor. In which direction should the uranium-containing rods in the diagram be moved?

left
up
right
down

Answer 1

I don’t have the diagram, so I can’t pick a direction from the four choices for that specific picture. A quick rule:

- If the rods in the picture are control rods (neutron absorbers like boron or cadmium): insert them further into the core (move them down) to slow the reaction.
- If the rods in the picture are uranium fuel rods: reduce reactivity by moving the fuel rods away from the core / from each other (i.e., withdraw them or increase their spacing).

If you upload the diagram or say which rods are shown, I’ll pick the correct direction from left/up/right/down.