Reboot nuclear safety regulation for the electrification era

“If you don’t pursue safety in a way that is cost effective, you are killing people,” wrote US physicist David Okrent. It is a principle that is largely ignored in current global approaches to the safety regulation of nuclear power. A small band of scientific experts has been calling on governments and the industry for a radical rethink; it’s time they got more of a hearing.

Nuclear power was going to power the world. After surging initially in the 1960s the rate of building tailed off, and especially since the Chernobyl accident in Ukraine in 1986. Since then far fewer plants have been built; costs per new plant have spiraled, and so have construction periods. Now, though there is a resurgence of interest in nuclear, it is proving very difficult to build new plants in many jurisdictions. Not a single new plant is under construction in the U.S., for example. Nuclear’s share of global electricity production is still falling.

Source: The Political Economic Determinants of Nuclear Power: Evidence from Chernobyl (2024)

This is despite nuclear energy having fundamental strengths unlike any other currently available power source. It is incredibly energy dense – millions of times more than fossil fuels, which themselves have energy densities orders of magnitude greater than intermittent renewables like solar and wind. As a result its material and land requirements per unit of electricity produced are far lower than any other electricity generation technique. 

Further – once plants are built, like solar and wind, nuclear has very low marginal costs of production – hence why nuclear-reliant France currently has among the lowest electricity prices in Europe. Unlike solar and wind, however, nuclear provides firm power – electricity when there is demand for it rather than when weather conditions are propitious.

The strengths of nuclear power extend to public health, too. Years of data prove that it is the joint safest way to produce electricity, causing just 0.03 deaths per terawatt-hours (TWh) of production, on a par with wind and solar – and 600 and 1,000 times fewer than oil and coal, respectively.

Even the most notorious nuclear power accidents that resulted in significant release of radioactivity – Three Mile Island, Chernobyl, Fukushima – have resulted in few or no public health impacts through radiation exposure. Or rather, where there were harms these came almost entirely from state and public over-reaction to perceived risks. For example, 100,000 abortions were carried out in Europe after the Chernobyl accident and a few thousand people died during or after evacuations in Japan following the Fukushima accident. Yet the only detectable public impact of radiation exposure due to a nuclear accident – calculated at some 800 early deaths – was due to ingestion of radioactive iodine in milk supplies following the Chernobyl accident, which could have been avoided by dumping contaminated supplies.

While the prevalence of grisly dramas on the Chernobyl disaster may create the perception of danger, and in turn the belief that the perception of danger itself is the main reason for nuclear energy’s decline, in fact the more likely main reason why nuclear power has stalled around most of the world is cost. Some experts point as well to a lack of standardisation of nuclear power plant design, and this may be a contributing factor; but it is indisputable that ever stricter safety regulation, and in particular the introduction of a regulatory principle that radiation releases should be kept “as low as reasonably achievable”, or ALARA, led to rapidly growing and now prohibitively expensive costs.

In the American case, this amounted to a factor of 10 increase in the capital costs of building new nuclear plants between plants completed in 1972 and 1983, which the man responsible for the original version of the chart below, John Crowley put down to “an effort to obtain the goals of ‘zero risk’ and ‘zero defects’ in an adversarial and legalistic regulatory environment.”

Estimated capital cost of new nuclear power plants in the US

Source: Why Nuclear Power Has Been A Flop, p279.

At the center of this discussion is the question of what, if any, worker or public exposure to radiation is acceptable in nuclear power. Official and regulatory views on this have shifted radically over the past century. In the 1930s it was thought that an exposure of about 2 millisieverts per day was acceptable. The prevailing standard for public exposure now is 1 millisievert per year, a 730-fold strengthening.

Yet low-level radiation exposure is actually an intrinsic part of life on Earth. In the U.S., the average annual dose received by members of the public from all sources is 6.3 millisieverts per year, half of which contributed by medical procedures. Airline crew flying polar routes can have an additional 6 millisieverts exposure per year. In some parts of the world, local geology adds to radiation exposure. The rate in Kerala, India, for example, is about 14 millisieverts per year from terrestrial radiation.

Because life on Earth developed under the constant influence of radiation, evolution developed sophisticated repair mechanisms. Our DNA carrying our genetic code is under constant attack, not only from radiation but also reactive oxygen species of molecules. It is estimated that everyone in the world has to deal with tens of thousands of single-strand breaks per day, and tens of double-strand breaks in DNA. It would require exposure to 250 millisieverts of radiation per day to cause a similar level of the more serious double-strand breaks. Not only is it clearly apparent that our bodies can cope with low levels of radiation exposure, but there is even compelling evidence of a phenomenon called hormesis, in which low-level exposure actually benefits health by priming genetic repairs to work more efficiently. 

Modern nuclear regulatory approaches ignore all this context, being driven instead by a maximal safety-first philosophy that is entirely disproportionate to actually observable risks and take no account of the comparable risks of alternative approaches to electricity production. Given that the World Health Organization estimates global deaths from fine particle air pollution linked to fossil fuel use at 7 million per year, the double standard is stark.

Regulatory authorities base their judgements on a dose-response model called linear no-threshold, or LNT. This posits that there is no “safe” level of radiation exposure, and also that risks decline in strict proportion as exposure decreases. The trouble with this is that it is not based on evidence: Rather it is an assumption, based on recorded exposures far higher than is relevant for safety standards set for public health such as exposure at plant boundaries or in surrounding areas.

A second key factor is that nuclear regulators apply a principle of keeping all radiation exposure “as low as reasonably achievable” or ALARA. Under this principle even de minimis exposure is still something to be reduced, in stark contrast to many other areas of regulation. Unsurprisingly, applying this principle is a gigantic driver of increasing costs.

The world can no longer afford such an unscientific and myopic approach to nuclear regulation, which is stifling a sector that desperately needs to grow alongside the renewable technologies of wind and solar, in order to deliver plentiful, cheap, safe and low-carbon electricity. Despite near universal agreement on the need to decarbonise the economy to ward off dangerous climate change, global greenhouse gas emissions reached a new record of 41.6 billion tonnes of carbon dioxide-equivalent in 2024. Notably, the new high in emissions occurred despite surging installation of new renewable electricity generation capacity, particularly of solar.

Emissions rose even as renewables increased simply because global energy demand is rising faster, as more countries develop. Within this picture, a new factor is that electricity demand is surging, driven both by economic growth and a trend towards electrification as a way to reduce greenhouse gas emissions. The recent arrival of generative AI, requiring enormous and power-hungry data centres, is further accelerating demand.

According to the International Energy Agency, global electricity demand rose by 4.3% in 2024 and over the next three years is forecast to rise by an “unprecedented” 3,500 TWh, the same as adding a whole new Japan’s worth of consumption every year.

More and more governments are seeing the need for nuclear energy to be part of the solution to rising demand for electricity and over 60 new nuclear power stations are now under construction, the highest level since 1990. However, half of these are in China, and outside of China (with the partial exception of South Korea), costs to build new nuclear capacity continue to hit record highs.

At the same time,  new nuclear capacity takes longer to deliver than any other type of power – often well in excess of ten years. As a result, many nuclear projects end up delayed and massively over budget. A recently opened new nuclear station at Flamanville in France, for instance, began operating 12 years late and four times over budget.

The good news is that there is now a healthy focus on how to reduce nuclear’s costs to fully exploit its potential. The advent of small modular and factory-built reactors, for example, offers the first ever real possibility of mass manufacturing, which has been key to cost reductions in countless other industrial sectors. New initiatives are seeking to cut the cost of capital for new nuclear power stations. Others are focused on streamlining the permitting process.

The missing element is a re-evaluation of overly strict nuclear safety regulation out of proportion with risk, which is a key driver of cost increases that have stymied the nuclear sector over the past several decades, and which will continue to hobble its renaissance into the future unless addressed. 

Prior to 1970, the US was building nuclear plants for an overnight cost of around $1000/kW in 2020 dollars. With technological progress and learning, construction costs should have decreased, as has been seen in every industrial sector, with solar power a stand-out example.

Yet in the nuclear sector, costs have only increased, driven largely by additional regulatory requirements, which have inflated both construction and labour costs, and lengthened permitting and build processes by years. The trend has been particularly severe in Western countries, with a recent analysis by UK think tank Britain Remade putting average US construction costs since 2000 at nearly $13,000/kW.

Key changes to nuclear safety regulation that should be considered include the following:

Regulators need to dump the LNT model that underpins nuclear regulation given its inability to explain why exposure to low doses of radiation does not lead to predicted harms. Scientifically more credible alternatives are available. A leading candidate is the sigmoid no-threshold, or SNT, model, which assumes lower impacts at low doses, rising with higher doses, and which agrees closely with real-world data on health impacts of radiation exposure.

Given that the lowest level of radiation exposure at which health effects have been reliably reserved is 20 millisieverts per day, the ALARA regulatory principle – which leads in practice to there being no cost increase too expensive to curb the slightest risk of radioactivity release – also needs to go. It should be replaced with permissible doses for both public and radiation workers. These should be set at more sane levels; the science says they could be increased by an order of magnitude while preserving a very high level of safety.

At the same time there needs to be a much greater focus on radiation dose rate rather than cumulative dose. Due to the body’s ability to repair genetic damage, a level of exposure that would be dangerous if instantaneous is virtually harmless if experienced gradually over a longer period. Therefore dose limits should be expressed on far shorter period than a year – most likely per day.

At the same time regulatory standards should focus less on prescriptive requirements on practices. It is not uncommon for regulators to specify in exacting detail thousands of aspects of both construction and operation of plants. This greatly increases costs at every stage for very uncertain safety gains.

Individual countries all add their own special hoops for nuclear energy projects to jump through. In the United Kingdom, for example, every individual nuclear project, rather than only general power station designs, must go through an individual Regulatory Justification step of demonstrating that benefits outweigh costs of radiation exposure, adding reams of paperwork – and very expensive determination processes – to licensing procedures.

The reasons why this kind of regulatory rethink have not happened so far are political and institutional. The public has a disproportionate fear of radiation, baked in through years of anti-nuclear campaigning, as well as a conflation in the public mind between nuclear power and nuclear weapons. Faced with this folk wisdom, democracies, in particular, have increasingly tended to give up on new nuclear. The first element of any change will have to be political courage by leaders.

At the same time, nuclear regulatory agencies have accreted an enormous amount of both power and institutional inertia around current approaches to ensuring safety. For instance, in initial responses to the 2024 ADVANCE Act requiring it to advance the benefits of nuclear power, America’s Nuclear Regulatory Authority has argued that it does not have the authority to consider the benefits to the public in decision-making.

Judgements like this have produced a maximal culture which allows for essentially zero risk of harms from nuclear power. This is demonstrably and widely inconsistent with other fields of human endeavor. Even worse, it also ignores risks of other ways of producing electricity.

Source: Michael A Arouet on X.com. Link

Nor are the real world harms of the world’s turn away from nuclear small. A recent academic paper estimates that the decline in new nuclear power plants caused by public opinion in the wake of the Chernobyl accident in 1986 led, via additional air pollution, to the loss of approximately 141 million expected life years in the U.S., 33 million in the U.K. and 318 million globally.

For decades now, nuclear power has been a Cinderella technology, to be tolerated only if it can be delivered at zero risk, unlike any other industry, or indeed any other walk of life. The need for a reassessment is now intense. Many Western countries have suffered years of economic stagnation since the Great Financial Crisis of 2008; high energy prices in Europe, particularly, are blocking off future economic growth; no other technology can deliver decarbonisation and electrification more safely or cost-effectively; key economic growth sectors of the future such as artificial intelligence demand more, and more reliable, electricity.

Or in the words of Matt Loszak, CEO of innovative US nuclear start-up Aalo Atomics: “Fission today is statistically as safe as solar or wind, there’s enough fuel on Earth to last 4 billion years, it’s clean, and it works around the clock: I don’t see any energy source better than that.”

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