It's politically difficult to tell people: "we're going to make changes to how we run our nuclear reactor" unless you have a very good reasons.

The Chernobyl disaster was only possible because some manager decided that it would be a good idea to let scientists do some experiments on a live nuclear reactor (and then let them disable multiple fail-safe systems, so that they were running without backups -- then they reacted badly to a lack of instrumentation). Sometimes, a healthy dose of "leave it alone" syndrome is a good thing; especially when mistakes can kill thousands of people.

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Ytrew