This Demonstration considers a model for a nuclear reactor using collision probabilities.
The graphic shows a plane view of four spheres, S2 for sample, C3 for control device, D4 for detector and E5 for extraneous source, initially at the summits of a regular tetrahedron in a multiplicative medium. It is assumed that there are no leaks from the pile P1.
You can change some parameters, moving the sample S2 of coordinates
out of the plane by sliding
or in the plane by dragging the yellow circle centered at
. Watch the effects on the collision probabilities
, detection rates
, neutron fluxes
and global amplification and multiplication factors. Gray levels on the plane view and the bar chart reflect the fluxes. If you see a white flash, you are dead.
is the inverse mean free path or total macroscopic cross-section,
is the multiplication factor and
is the spontaneous source. For all
is the sum of
-weighted average over all regions.
is the probability that a particle emitted in region
first collides in region