On Nuclear Power

With the recent developments at the Fukushima I & II plants and apparently I just read another plant, lots of discussion unsurprisingly about nuclear energy. I’ve found the subject fascinating since I was a kid and first saw the National Geographic article about the Chernobyl Nuclear Power Plant Disaster of April 26, 1986.

I grew up on the other side of Toronto from Pickering, which is home of the eight-reactor nuclear power station. Just east of Pickering sits the Darlington Nuclear Generating Station which houses another four reactors. So I was even more fascinated. Being the geek that I often am I studied a fair but on how nuclear power works, the risks and so on. I even considered a fee years ago going back to school to learn to be a nuclear operator at one of those plants. I’ve worked with a couple of them through the military and learned even more specifics about how it works.

So here’s my opinion on the matter. Nuclear power obviously has risks – when accidents happen they are spectacular. But they are also extremely rare. The Level 4 accident at Fukushima for example is only the third major accident in something like 40+ years of civil nuclear power production, the others being of course Three Mile Island and Chernobyl. TMI was really fairly minor, because even though the core was destroyed during the incident, relatively little radiation escaped into the environment, and the long term effects were fairly minor.

Chernobyl is the usual point of reference for nuclear accidents employed by anti-nuclear folks, but the reality is that it is a rather far-fetched comparison. When I had someone really explain to me what caused the catastrophe at Chernobyl, and why it’s basically impossible to have something like that happen at any modern Western-designed plan (or any of the new Russian designs either), I come to realize that I still see no problem with nuclear. Well, that’s not true. There are problems, but the risks are manageable.

Most opponents of nuclear energy demand clean, renewable energy as an alternative. The problem is that there currently exists no such technology, except hydroelectricity which still has its share of environmental impacts. Wind and solar energy are simply not able to meet base load requirements so it is more useful to compare nuclear energy to those sources. In particular coal is what I would happily see replaced by new nuclear plants. I suspect that burning massive amounts of coal causes much more damage to human health than nuclear even accounting for accidents. Coal-fired plants spew a myriad of pollutants into the air, including mercury, other heavy metals, and of course greenhouse gases. The industry’s defense of “clean coal technology” is just a classic greenwashing case.

So let’s consider the main problems of nuclear energy, though I’m not going to be able to go into much linked detail because I’m punching this out from my iPhone, I just want to prompt some thought and maybe a little bit of discussion.

The main problem that gets highlighted, of course, is the possibility of catastrophic accidents. Modern containment designs abate the risk of the kind of disaster that happened in Chernobyl. In Japan, even though the outer structure has been destroyed, the actual vessel containing the fuel is intact, though some fission products have escaped. It of course remains to be seen what the final outcome is. The fact is that disasters of this magnitude are very rare and health concerns need to be weighed against what fossil fuels do, not against theoretical clean alternatives which do not yet exist.  The reality is that both Three Mile Island and what’s been happening in Japan so far seems to show that good containment structures work.  The reason Chernobyl was such a disaster had to do both with some major design flaws in the reactor itself, and a complete lack of any sort of containment.  When Chernobyl’s operators, who were conducting an unauthorized test of the reactor’s behaviour at very low power, set the conditions for a dramatic excursion, there was nothing at all to have any chance of containing the massive steam explosion they created.  One could argue that even if there was, it may have been blown apart anyhow, but then we still have to default to the point that what they were doing, which caused the disaster to begin with, was not normal operation.  Wikipedia has a very thorough article about what happened at Chernobyl which explains it well.  My friend Jeff, a nuclear operator at Pickering NGS, explained it well to me though, and I’ll try to summarize it.  Basically, what they wanted to do was see how the cooling system would react to the reactor running at very low power.  To do so, they added a large amount of “reactivity poison”, essentially a substance that absorbs neutrons, the “bullets” which actually split uranium atoms in the reactor.  They then got a call to power up Reactor 4 from the grid control station, and to do so they had to pull every single one of the control rods (which are sort of like the brakes on the reactor) completely out of the core in order to get it going.  Normally this never happens – but because there was so much poison in the core they had to literally pull out all the stops.  Problem is, as the neutron absorber does its job eventually it become saturated, which is precisely what happened – the reaction sped up at an alarming late, and when the operators dropped in all the control rods in a panicked effort to shut down the reactor, a design flaw in the rods actually sped it up, making the reactor jump far beyond its capacity, vaporizing all the coolant and creating a massive amount of steam under pressure that heavily damaged the fuel channels and then caused a second, massive explosion that blew the top off the reactor somewhat like a champagne cork.  It spiraled through the air and crashed back down, smashing the core, which was starting to melt down already.  Then all the graphite moderator started to burn. And so did the roof of the reactor building, as it was made with bitumen.

Much was learned regarding the design flaws, and the reactor design was massively improved with retrofits.  Some RBMK-type reactors still operate in Russia, but only with some major improvements from lessons learned after Chernobyl.

See why something like that isn’t likely to happen again?

The second common concern is about waste. Yes. Nuclear reactors produce ware in the form of spent fuel and also various other forms of low level waste. But the volume of spent fuel is a lot less than many people think. The plant I used to work very close to, Pickering, has been around for something like 35 years. All of the spent fuel it has consumed in its entire life is stored on site.  First it’s cooled for a few years in a massive pool, then it’s put into “dry cask storage containers” which can be stored in outdoor compounds indefinitely.  As for LLW, most of it can be simply landfilled in specially designed facilities.

There is of course a need to have a long term repository for waste storage, but things like salt caves and other deep repositories will work reasonably well especially given how well we can pack the stuff – with technologies like vitrification.

Fission reactors using uranium aren’t the be-all and end-all of the technology. There are other fuels – particularly thorium – and designs, and eventually there might be commercially viable fusion reactor design. Canada was involved in research into a project called Iter, but pulled out which is too bad. That has a lot of potential.

So in summary, nuclear isn’t so bad in comparison to realistic alternatives but you need to do a bit of homework to understand it first.


2 comments so far

  1. DanVerg on

    Good article. I break from traditional liberal orthodoxy when it comes to nuclear power, which I am massively in favor of. In addition to what you said, I think nuclear power will play a crucial role in the real, deep, thorough exploration of space that is still only in its infancy. Planting a stick on the ground and praying for goo to come out (as Mr. Burns so eloquently put it) cannot possibly be the way of the future.

    • warriorbanker on

      Like most posts, I just bash stuff out quickly and don’t really get enough depth I guess. The thing is, I tried to highlight the main problem I see, which is comparing nuclear to actual alternatives, not non-existent completely clean sources. There simply aren’t any yet that meet our needs.

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