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Light_bulbnz t1_irtisvf wrote

Reply to comment by Goetterwind in How did they fix the RMBK reactors? by Henricus_3141

>The fundamental flaw was to get people in charge that had no idea how the reactor worked and where and why it is dangerous.

I would choose to disagree on this point. They knew how reactors worked, but the design flaws and things like the positive void coefficient were deliberately hidden from them by the designers. They disobeyed the operating instructions, but did so because they were kept from knowing why those operating guidelines were put in place, and so things like the minimum number of control rods to be kept inserted at all times appeared like an arbitrary guideline, rather than something essential for safety.

It's easy to draw conclusions based on the more complete understanding we have now, but the message at the time was that it was impossible to blow up a RBMK; it was "as safe as a samovar".

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jammerjoint t1_irtkx9k wrote

In addition, added political pressure to brute force results despite running into problems.

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Light_bulbnz t1_irtsyv0 wrote

Well, this particular test was supposed to have been done before Unit 4 came online in late December 1983. But the unit was signed off as complete without the test being run in order to meet the end of year deadline. The planned shutdown in 1986 was the first real opportunity to take the unit offline to run the test as they had ~3 year cycles between maintenance shutdowns.

In normal operating situations the accident should never had happened, but given the culture and pressures at the time, it really was inevitable.

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Bensemus t1_isn8rn0 wrote

They had tried to run the test a few times but it failed. It failed for the las time because they couldn’t fully shut down the reactor due to power needs and had to push the test to the next shift when power needs were less. It wasn’t about taking the reactor offline for maintenance.

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Light_bulbnz t1_isn9p07 wrote

The reason why the test was scheduled for this time was because they were taking the reactor offline for maintenance. It was delayed for hours due to the power needs of Kyiv.

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LaDolceVita_59 t1_irxa54e wrote

What you want is people who know how it works, and how it works when things are not working.

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Columbus43219 t1_irumvcu wrote

I'd even back up a step further and say they knew about he coefficient, but not that the control rods had graphite tips. THAT was what was hidden from them.

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