Chernobyl

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Chernobyl, as seen on TV

HBO’s Chernobyl series has gotten a lot of people talking about that fateful night back in April 1986. While I’ve not seen the series in full yet, I am sufficiently familiar with the accident to know the chain of events. And from what I have seen, they seem to have mostly engaged in a lot of Russia/Soviet bashing. Which, as you can imagine, Putin ain’t happy about. Nor are the cheerleaders of nuclear energy happy (they’d rather we all just forget about it). So there is a need to separate some of the facts from fiction.

I mean, how could the Soviets be so reckless as to build a nuclear reactor with a dangerous graphite moderated core and no containment building?…what you mean like the Magnox and AGR’s in the UK (Graphite cores, no containment building although they are gas cooled), some of which are still operating, one not that far from my house. Or, how could they build a civilian nuclear reactor with a positive void co-efficient?….you mean like the Canadian (and Indian) heavy water reactors, which also have a positive void co-efficient (although lower than with an RMBK).

There is plenty of reasons to criticise the Soviet union as regards Chernobyl (we’ll get to that!), there’s no need to start inventing reasons. For starters, why were the RMBK reactors, or the aforementioned Magnox and AGR’s, built without a containment building? Well firstly it won’t have made much difference any way, given how enormous the explosion was. The Fukushima reactors did have containment buildings and they were simply blasted apart by the force of the explosion. Even if the designers could have anticipated this, given the large size of of an RMBK, or gas cooled graphite cored reactors (about 20m in diameter v’s about 5m for a PWR with a similar power output), a containment building big enough to contain such an explosion would be enormous. As much as two hundred meters high and maybe 50m in diameter with walls several meters thick. Hell, if you’re going to throw that much concrete around, you’d be better off just building a dam!

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The size of different reactor cores compared

So the designers of these reactors, both in the west and the soviet union, didn’t bother installing such containment buildings. And in part this was because such a structure was considered unnecessary, because such an explosion shouldn’t happen (they did not have the benefit of hindsight). The RMBK reactors had an elaborate computerised control system that reacted to any changes in the reactor’s power levels to constantly keep the reactor in a safe operating condition.

Of course this created two dangerous flaws. Firstly, the computer could only do this job if it was still operating. A loss of on-site power would not only take out the computer, but all the sensors and the circulation pumps as well. Hence the need to perform a vital “safety test” to prove that they could use the inertia in the plant’s steam turbines to keep the power going for long enough to give the backup diesel generators time to start up and take over. This was the very test the crew were performing on that fateful night.

Secondly, to err is to be human. We screw up and make mistakes and by definition any system that assumes we won’t is kind of flawed. And this is particular a problem when people aren’t adequately trained or simply doing a job they aren’t qualified to do. The soviet union’s ability to build nuclear reactors had rapidly outpaced their ability to train staff to operate them safely.

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The control panel of Chernobyl reactor number 1 (not the one in the accident, that was number 3) and the infamous AZ-5 button, top right

And the crew on this particular night shift were very much the B team, lacked the proper training or qualifications (nearly all where just electrical engineers rather than nuclear engineers). Indeed they’d shown up for their shift assuming the test would be over and the reactor in shutdown mode. Plus the user manuals they’d been given were wholly inadequate. Parts of it were even crossed out, with it not clear what to do if there were conflicting instructions. The manuals also made no mention of vital details of the plant design (such as the fact the boron control rods had graphite tips and how this would aggravate the reactor by displacing the water), it failed to mention how vital it was that they kept the computer and its safety systems turned on at all times (instead they ignored warnings from the computer and turned off vital safety systems).

In short, it was an accident waiting to happen. While yes some of the actions of the operators have to be criticised, the fact remains they were not adequately trained or informed. Its a classic systems failure. The USSR should have suspended the operations of plants such as Chernobyl until such time as the safety tests could be conducted properly and there was a sufficient number of suitably qualified staff on site to operate them. But of course they didn’t, because they were driven by targets set by the politburo in Moscow divorced from any semblance of reality, leading to corners being cut.

Another criticism is how the soviets were very slow to admit to the west (or even to the their own people) the full scale of the disaster. The first the west knew about it was when radiation alarms started going off at a Swedish nuclear power plant (which needless to say, the Swedes were none to pleased about). This is one of the reasons the response was so haphazard in the beginning. By contrast, Fukushima was handled better because the Japanese were much more forward about their problems, both to the public and the international community. When it comes to nuclear safety, honesty really is the best policy.

Oh and a myth that needs to be debunked is that Chernobyl was part of the soviet nuclear weapons programme. It wasn’t. The soviets had plenty of other facilities in the country making plutonium….as well as also creating lots of big accidents, some of them on a similar scale to Chernobyl (including one infamous double Darwin award). Much like Chernobyl, the country’s ability to safely build nuclear weapons was being outrun by the demand for them.

One controversial topic with regard to Chernobyl is the body count. Ask nuclear energy supporters and they’ll say it was only a few dozen, as they’d argue you’d have to do a belly flop into the reactor to count. While if you listen to Greenpeace its several hundred thousand, as they count anyone in Eastern Europe whose died of anything remotely radiation related since then. Obviously the truth lies somewhere between these two extremes, with figures of several thousand considered a reasonable estimate. However, I would argue that such debates miss the point. Chernobyl destroyed the health and the livelihoods of a vast number of people. It led to the displacement of entire towns and villages. And from what bits of the HBO series I’ve seen I think this is something the series seems to capture.

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This also highlights what I’d argue is the key lesson from Chernobyl. It was basically a fire drill for the aftermath of a nuclear attack. And even with the help of the international community, the soviet’s struggled to cope with the aftermath of one such incident. How exactly do you think they’d fare with the same or worse going on in every major city in the country and no help from abroad. How would the west cope? Probably not very well. And that perhaps is the lesson that needs to be learnt from Chernobyl.

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About daryan12

Engineer, expertise: Energy, Sustainablity, Computer Aided Engineering, Renewables technology
This entry was posted in energy, environment, history, nuclear, power, sustainability, sustainable and tagged , , , , , . Bookmark the permalink.

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