Category Archives: Nuclear power

Posts about nuclear energy

Nuclear uncompetitive in the marketplace

In a survey on nuclear power written for The Economist, Oliver Morton does a good job of explaining one of the reasons why nuclear power is unlike any other form of electricity generation:

In liberalised energy markets, building nuclear power plants is no longer a commercially feasible option: they are simply too expensive. Existing reactors can be run very profitably; their capacity can be upgraded and their lives extended. But forecast reductions in the capital costs of new reactors in America and Europe have failed to materialise and construction periods have lengthened. Nobody will now build one without some form of subsidy to finance it or a promise of a favourable deal for selling the electricity. And at the same time as the cost of new nuclear plants has become prohibitive in much of the world, worries about the dark side of nuclear power are resurgent, thanks to what is happening in Iran.

None of this contradicts the argument that we need more nuclear plants to deal with climate change, but it does highlight some of the special risks associated with the technology.

Rickover to Carter, on Three Mile Island

In The Quest: Energy, Security, and the Remaking of the Modern World, Daniel Yergin quotes extensively from a letter that U.S. Admiral Hyman Rickover sent to President Jimmy Carter, about the causes of the Three Mile Island nuclear disaster:

The only reference to the letter online seems to the the Google Books result for Yergin’s book. It would certainly be interesting to read the letter in its entirety. Rickover is known as the ‘father of the nuclear navy’ – and he also had a great deal to do with the emergence of civilian nuclear power. Carter’s history also involves nuclear energy in several ways: he served aboard American submarines, and also participated in the cleanup after a meltdown at one of the Canadian nuclear reactors at Chalk River.

Nuclear and climate risks

When operated by human beings, nuclear fission is a bad technology. It is the equivalent of handing a credit card to someone with expensive tastes and no self-control. While it could theoretically be used responsibly – if the people in charge can resist their more harmful temptations – in practice, it is likely that will not happen.

Regardless of who runs nuclear power plants, they will skimp on maintenance, cut corners, cover up problems, and keep running the things after they have ceased to be reasonably safe. There will be lots of accidents the public never knows about, and companies and governments will lie about the seriousness of all accidents serious enough to attract outside scrutiny.

At the same time, humanity is running a calamitous risk by continuing to rely on fossil fuels. If nuclear power reduces how much coal, oil, and gas are burned, it may play an important role in keeping the amount of climate change humanity experiences to a moderate level.

Human institutions may be ill-equipped to run nuclear plants safely, but human beings are perhaps even less willing to accept restrictions on their use of energy. There should be no mistake that humanity is gambling on the future of the species, by continuing to burn fossil fuels with abandon. Compared to that, the risks of nuclear power look more moderate.

It’s a monster of a technology – ugly and menacing – but it may be one of the less bad options for humanity going forward. Of course, that reflects just how troubled the future of the human race might be.

Half as bad as Chernobyl

Some recent news stories have claimed that the amount of Cesium-137 released by the Fukushima disaster in Japan has been half what was released at Chernobyl. Some news sources have suggested that this is an encouraging figure, but it looks pretty terrible to me.

The Chernobyl disaster involved a reactor design that was deeply and fundamentally flawed, followed by a series of mistakes from a secretive government that cared little for the health and welfare of its citizens. By contrast, Japan’s government is supposed to be good, along with their building standards, oversight, and emergency preparedness.

If a nuclear disaster in Japan can be half as bad as Chernobyl, it suggests to me that perhaps nuclear energy is just too fundamentally dangerous to be made safe in the real world – a world in which companies and governments will always try to cover up their mistakes, and in which they will hesitate to spend billions of dollars to improve the odds of a nuclear plant getting through a disaster without contaminating the area around it and putting the human population in peril.

It is certainly possible that scaling back plans for new nuclear reactors will make it harder to deal with climate change. At the same time, we should recognize that the economic costs of nuclear are very high and largely hidden, even when everything is going well. Perhaps we can recognize the dangers of nuclear, and respond by redoubling our efforts to deploy safe and renewable forms of energy, while working to reduce the level of absolute energy usage globally.

Zircaloy is a problem

Fuel rods in many types of nuclear reactors consist of pellets of fissile material (uranium and plutonium) sheathed in a metal alloy called zircaloy, made unsurprisingly from zirconium.

Zircaloy seems to be one of the major reasons why the Fukushima crisis is scary. When the earthquake happened, the reactors automatically inserted neutron-absorbing control rods to stop the nuclear chain reaction. This process is called a SCRAM. Despite this, the fuel rods are still producing heat because of other ongoing nuclear reactions (decay heat). This is what makes Zircaloy so worrisome, because when it gets heated up it can oxidize or burn exothermically, producing even more heat. That adds to the risk that fissile material will end up in the wider environment. It also adds to the risk that the nuclear fuel will melt, dribble down to the bottom of the reactor containment vessel, and re-form a critical mass.

That’s the really scary possibility, as far as reactors one, two, and three at Fukushima are concerned. If the fissile material in the fuel rods forms a critical mass again, it could melt through the bottom of the containment vessel. It could also trigger a large steam and/or hydrogen explosion that could spread radiation further.

There are other risks with Zircaloy. When hot, it oxidizes in the presence of water, stripping oxygen from water molecules and producing explosive hydrogen. Zircaloy is also what makes spent storage pools so scary. If they lose cooling, the rods can heat up, burn, and release large amounts of radiation into the environment. Cooling ponds are not placed inside containment vessels in the same way reactor cores are.

So, what seem to be possible lessons learned here?

1) If it is possible to find something better than Zircaloy, we should. It needs to have a low neutron cross-section, so that neutrons from different fuel rods can induce fission in one another. At the same time, it would be really nice if it would not oxidize exothermically, generate hydrogen in the presence of water, or burn.

2) Perhaps spent fuel cooling ponds should be inside containment structures.

3) Perhaps containment pools should be embedded in solid rock, not perched atop buildings.

It’s possible there is no material that satisfies (1) and it is possible that (2) would make nuclear reactors impractically expensive. If so, perhaps the appropriate option is to pull back from nuclear power as an energy source and concentrate on reducing total energy demand, while deploying renewable forms of energy.

Nationalize the nuclear industry?

In an informative question and answer piece in The New York Times, R.J.M Hudson raises the question of whether nuclear power stations are too hazardous to be run by private companies. Perhaps it makes more sense for them to be nationalized and run by the state. Governments still have some incentive to cover up problems, but at least there would be less of a profit motive driving decisions.

Of course, there have also been plenty of nuclear accidents in state-run facilities.

Would people feel more comfortable if all the world’s nuclear plants were directly owned and operated by governments?

Nuclear power after Fukushima?

While the full consequences of the ongoing nuclear crisis in Japan cannot yet be known, it is worth speculating about what impact this will have on the co-called ‘nuclear renaissance’ and global efforts to combat climate change.

Certainly, the accident demonstrates some of the special risks associated with nuclear power. Like renewable forms of energy, nuclear is relatively costly and slow to deploy. Using nuclear power also creates the risk of very serious accidents, nuclear waste, and weapon proliferation. That being said, it is possible that climate change is such a severe problem that it is worth running those risks in order to improve our odds of dealing with it.


Keepin’ Carbon Underground

For the last 10,000 years during which human civilization has emerged, the planet has had a relatively stable climate. Carbon embedded in coal, oil and gas has been a major establishing feature of the climate around the world.

Since the Industrial Revolution, humanity has been burning those fuels at ever-increasing rates – rapidly returning that carbon to the atmosphere. As a result, we’re on track to heat up the planet by more than 5°C by 2100. That is far beyond the 2°C threshold of warming that scientists and policy-makers have widely accepted as ‘dangerous‘.

The solution to human-induced climate change is to leave most of the world’s remaining fossil fuels underground. That way, the carbon they contain will be kept in a place where it doesn’t affect the climate. To accomplish that, we are going to need to find alternative sources of energy. Nuclear fission is one of the temporary bridging options. However it has its own issues: it has non-renewable fuel and waste and proliferation problems. Ultimately, though, if humanity wants to power itself in a way that can be perpetuated forever and which does not threaten the climate, we’re going to need to draw the energy we need from renewable sources: hydroelectricity, solar power, wind, tidal, geothermal, and so on.

Given how much it would transform our world – and how many human lives that would harm – we need to keep most of the carbon still locked in fossil fuels underground.