Reply #6: My question..

[girl gone mad]

I thought the reactors had good neutron shielding, which is why I assumed a beam would also indicate damage to containment. Are beams something the workers have to contend with normally?

He does a good job. I would also add that neutrons are unstable and decay into protons within minutes (then pick up free electrons to become hydrogen). This is why the presence of an unexpected number of neutrons would indicate very recent chain reactions.

The chain reactions will generate heat and can potentially raise the steady state power levels in the reactor, but the heat will also cause the fuel to expand which will slow the reaction down so it is self-regulating to some degree. The fission products released in these chain reactions are a bigger concern, in my view, especially if there are breaches. It makes the environment for the workers much more dangerous.