[kqr]

Procedures are written under the assumption that the actual system behaves like the theoretical system the engineer has in their head. It never quite does. There's always a gap, and this gap nearly always requires deviating from procedures to ensure safe operation.

Deviating from procedures prevents as many accidents as it causes. Safety cannot be based on adherence to procedure. Safe systems must be designed to take advantage of (and be protected against, I suppose) human ingenuity.

[colechristensen]

This is nonsense, especially this line.

>Deviating from procedures prevents as many accidents as it causes.

And they weren't doing some small deviation from procedure. They were doing something that was expressly forbidden and they knew why it was forbidden. In the time leading up to the accident it would be difficult to distinguish between what they were doing and trying to intentionally cause a meltdown. In a reactor experiencing xenon poisoning instead of shutting down for 24 hours (procedure) they removed every nuclear reaction moderating mechanism they could.

This isn't a smart little deviation, it's pouring gasoline on a fire and hoping for a good outcome. It is hard to describe how stupid this was.

[Retric]

They are referring to a wider range of situations than this very specific incident. There are many accidents that have been avoided by modifying procedures on the fly. Pilots discovering letting go of the yoke/stick solved some seemingly unrecoverable spins is one example. Though obviously techniques that work eventually get adopted to the procedures.

It generally requires operators to know how the systems work in great detail which would have avoided the specific Chernobyl incident.

[rob_c]

> It generally requires operators to know how the systems work in great detail which would have avoided the specific Chernobyl incident.

Hence the above comment doesn't fit with the discussion. The level of "bad" being done by the engineers was right out of the "never do this" list of actions. Unfortunately there's a lot of evidence that bravado or "experience" is what led to them thinking that they knew better.

Not following procedure is fine if it's turn it left not right. It's not good when instead of turning a valve they take a hammer to it. That's throwing instructions away and so makes any sensible discussion from there on mute.

[Retric]

I’d be careful how you blame to operators vs power plant designers vs people designing the test vs the USSR’s culture at the time.

In that exact situation you could swap many people inside the USSR into those roles and likely get a similar result. The specific people who decided to cover up RBMK’s flaws were responding to the same incentives as the people who covered up an earlier serious incident at Chernobyl on September 9th 1982 etc.

The U.S.S.R. had a lot of nuclear issues, and there’s arguably more to learn from the indirect causes than the direct ones.

[rob_c]

For the case of this incident unfortunately yes it lies with the people stepping off the page and doing something the designer never intended.

That being said yes. Lots of lessons to be learned including, why did you build a system that allows them to do this?

Cause is easy to attribute, identifying who was irresponsible and blame less so. In this case it was caused by the operators.

[Retric]

Taking out an excessive number of control rods is something that many people have attempted including US operators. If the reactor lets you do it then that in and of itself is a massive design flaw.

[colechristensen]

Sigh, I'm done. Y'all would fail any technical interview I'd ever give regardless of your experience level.

Going on and on about the merits of not following procedure in a discussion that started with a disaster which could have triggered a global mass extinction event is not the appropriate response. They were doing things which were very well known to be dangerous, which they themselves knew to be dangerous, that had been known to be dangerous since literally the first nuclear reactor at the Manhattan Project some 40 years previous.

[Retric]

And you’d absolutely fail mine for on both technical grounds, and hyper focus on irrelevant details. “could have triggered a global mass extinction event” WTF

I can only hope you’re never involved in safety critical systems. Procedures simply can’t account for multiple independent failures at the same time in complex systems without defaulting to individual judgment, the problem space just grows too large.