Decades ago, I attended a nuclear engineering course at Hinkley (or perhaps Oldbury - both power stations with gas-cooled magnox reactors.) I recall being told that the reactor had a slightly positive thermal reactivity coefficient. It had an automatic control system that did not work well, so they operated it manually. There was a simulator for training, run at 10X real time, and we all got to try our hand. It was not difficult, even at the sped-up rate.
There were multiple automatic safety systems ready to stop anything bad happening if the operators somehow lost control of it.
There were multiple automatic safety systems ready to stop anything bad happening if the operators somehow lost control of it.