Comment Re:You're both right, and both wrong. (Score 1) 311
What makes you both partially correct is that there isn't a delay in fission, but a delay in neutron release.
From reading the linked Wikipedia page, I get that the delayed neutrons are responsible for 0.6% of all neutrons emitted from fission, and most of them with half-life times between 2 and 20 seconds. While this makes for some nice control bandwidth (you can afford to be 0.6% off with the control rods without getting an instantaneous nuclear explosion), I don't see how these delayed neutrons can be responsible for the majority of the 7% decay heat.