Nuclear power — expensive catastrophe or low-carbon saving grace?

Atoms and radiation, Chernobyl and Fukushima, big chimney stacks and black signs on yellow background. There’s a lot of things that pop into your head when you think ‘nuclear’.

There was a wave of thinking in the 90s and 2000s that nuclear was the way out of fossil fuels. But 2011 came and with the water receding from the nuclear power plant at Fukushima after the flood, so too did the hopes of nuclear.

Source: Pexels

But why was nuclear so well-regarded before, when Chernobyl happened and why are there still voices advocating for the mushroom cloud-spitting power plants? Here’s a short attempt at checking those myths and urban legends about nuclear power and seeing what’s what about it.

You might ask — how exactly does nuclear power work? Well, if we skip the jargon-filled explanation of the different systems like salt-cooled, lead-cooled and gas-cooled, the principle is pretty similar.

Atoms are held together by a very strong force, but this force gets weaker the more protons and electrons the element of choice has. So if you picked the element with the highest number of both of those that occurs in nature you get… *checks elemental chart* …. Uranium. When you throw neutrons at the atoms, you can force them apart, releasing all the energy holding them together. This is called nuclear fission (meaning break apart).


You split a uranium atom, but this happens in a sort of atomic soup, where all surrounding atoms get hit by the rogue particles and it causes a chain reaction. In a reactor, this is contained by control rods that try to keep the activity contained inside.

There is another possibility of producing power with atoms and that’s nuclear fusion. This is what goes on at the heart of the sun and makes it burn. At the moment, the technology for that isn’t quite ready for center stage, but it uses the opposite principle: you throw atoms at each other and hope to merge them into an atom of higher energy, the leftover energy is what you try and capture.

Back to fission

The chain reaction releases energy, which causes a lot of heat. The heat is used to heat up water. The steam from this process turns a turbine and produces power.

Bit of important background here: nuclear power plants have existed since either 1954 or 1956. Technically, there’d been experimental power plants before that, in the late 1940s in the US and elsewhere, but the first notable ones were at Obninsk in the former Soviet Union and at Calder Hall in the United Kingdom. These and most nuclear reactors installed up until about the late 1960s are what’s called Generation I reactors. This generation concept is essential if you want to understand how they’ve progressed since those early models.

Those first plants and the enthusiasm for nuclear in the 60s and 70s led to literally hundreds of plants being built and launched. After all, nuclear didn’t come with the dirt and soot of oil and coal, but produced reliable and clean power. In the US, there was even a turnkey trend for building plants and then finding a buyer. But this came with massive financial and engineering problems. (spoiler — multiple operating companies went bankrupt)

Currently, most of the nuclear power plants out in the world are Gen II, some Gen III (installed between the 1990s and 2013) and one or two Gen IV. The improvements from Gen II to Gen III and IV respectively are all about reducing the period that unspent nuclear fuel is dangerous for to only a century or so as opposed to the millenia it takes for fuel from Gen II, better energy yield for the same amount of fuel, better safety mechanisms and crucial for calling nuclear a renewable source: reusing the unspent fuel. This is called Closed Nuclear Fuel Cycle.

All three large scale incidents with nuclear power plants — Three Mile Island, Chernobyl and Fukushima, happened at early Generation II reactors.

This is all very technical, but there is also the economics side of it. Here’s where nuclear is both massively in the lead and very far behind and gives a lot of headaches for any politician trying to get one in his or her constituency.

Nuclear is pretty expensive when run at full capacity (per material consumed) — cheap-ish per unit, but when you don’t count the monstrous cost of building the plant. The cost of building the plant is about 80% of the unit cost of producing nuclear power. Unlike coal or natural gas power plants, nuclear comes with a whole host of security features that are designed to prevent another catastrophe. However, of the cost of building the plant, 30% can be interest payments over the period when construction is happening. And if there’s a construction delay, the interest goes up.

The main measure of assessing nuclear power plant cost is LCOE — Levelised Cost of Energy. This averages out the cost of construction, fuel and maintenance, plus decommissioning over the plant’s lifetime. With that, the average US LCOE was 132 in 2015 and rising. According to Lazard, this was 148 USD in 2017 against 60 dollars for natural gas and between 45 and 50 for wind and solar.

The United Kingdom

In the UK the plants are mostly of the AGR (Advanced Gas Cooled) type and have been run at significantly below full capacity for a long time. This is partly because they’re getting quite old. If you run power plants below capacity you don’t actually benefit from any savings and this is usually done for safety reasons rather than economics.The nuclear capacity in the UK in 2017 was 77% but in the decade before that, it was running anywhere between 50 and 70%. That wasn’t a consistent ‘let’s run it at half-capacity for this year’ but a result of planned works, maintenance and safety features.

Nuclear has so far served a very useful purpose: base load. While other power plants can make savings by optimising how much they output depending on what the pressure on the power grid is, nuclear plants have a slow and steady thing going on. They are the slow ruminants of the power plant family. But now that weather-dependent renewables are taking the lead, the scope for nuclear is decreasing: before 1998, 90% of all UK low-carbon electricity came from nuclear, while in 2017 solar and wind provided 70%!


However, there’s a bit of a self-reinforcing loop here. In the US, there have been no new nuclear plants between 1979 and 2012. Which means no construction company had any experience building them. What this meant, in the US at least, was newer reactors were to either be built with local companies who would underestimate the task and costs (or maybe underbid — that’s also a problem with government tenders) or foreign companies that had to get up to speed on local practices and the environment. But there’s another element — the more plants a country built, the more savings it could make from that experience in construction: in Korea and Japan, there were nuclear plants finished in less that 5 years in 1996/97 in Korea and 2005 in Japan.

And those designs ended up producing cheaper power — at about half the cost per unit as in the US or the UK. (LCOE in Japan and Korea around 60 US dollars per MWh versus 110 in the US and 130 in the UK).

Now you might think — nuclear, pack your bags, solar and wind are here to stay, we’re done with your antics. But the reality is — and this is also the main reason why politicians these days are so on-off-and-on again with nuclear — until energy storage becomes cost-efficient and wide-spread enough that solar energy can be stored for night-time and wind energy for when it’s dead still, nuclear might still have a reason to exist.

The cost of them and the negative reputation they have is definitely not helping the argument. I mentioned that it’s always there, but the reality is for every plant producing X GWh, you need an alternative power source in case of outages or engineering works, making nuclear fission even more complex to include in the world’s energy mix.

But the final argument rests on whether we think it makes economic sense to drive a nuclear renaissance on the basis of the new safety developments since the 1970s (it would be silly to assume they’re the same as the ancient plants that did have accidents, but it would equally be crazy to assume they are now risk-less) and whether we think by the time these plants are finished we won’t have commercial scale battery technology. Without full-scale storage, solar and wind are circumstantial at best and there may be a place for nuclear in the energy mix, but with them, solar and wind are unrivalled in cost and efficiency.

A deep dive into energy storage is coming next.


1.Page 7 of the document shows a chart of different Generation timelines:

2.A brief explanation of nuclear reactors here:

3.Better visualised here. See also for history of nuclear power plants in the US:


5. An explanation as to why the UK power plants were under capacity:

6. Cost of Solar per kWh (2018, Table 10, page 48):

7. The economic counterargument to nuclear:

8. Detailed cost structure and where each cost can go wrong:

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