On 25/02/2021 17:14, Tim Streater wrote:

The danger comes from the poor use of whatever it is. So enriched uranium and
plutonium, f'rinstance, will be dangerous if you let the wrong people play
with it. Or if you design a reactor which can be unsafe and don't train its
operators properly. If OTOH you design it to be inherently safe, which is what
happens these days, then you're much better off. Chernobyl happened because of
a poor design AND bad luck AND poorly trained operators. Remove any one of
these and the reactor operates safely.

AIUI Chernobyl was supposed to run the test in the early evening, using
the day shift that had been trained and briefed for the task.

An unexpected demand for power meant that the controller in Kiev, who
knew of the test, rang Chernobyl to ask them to keep the reactor online
until demand had dropped. By the time this happened and the controller
had released the reactor, the trained day shift had handed over to the
night shift. These people knew of the test and I believe had the
protocols to hand. Someone decided the test should go ahead. However,
there should have been a reactor expert on hand in the control room, but
for whatever reason he wasn't there, so vital clues were not picked up
by the operators.

So the chain of errors that led to the reactor running away was quite
long, and if any single one had not happened, we'd never had heard of
the place.

--
Spike