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Nuclear comeback?
Nuclear comeback? Nuclear power is dying in the West – but a raft of new technologies could yet revive it, says Chris Baraniuk
Q
UEEN Elizabeth II climbed the five metal steps to the platform and spoke a few words into a microphone. She pulled a lever and the deed was done. A giant dial on a nearby building began to spin, as electricity sparked into life. She had just opened the UK’s first atomic power station, Calder Hall. The crowd clapped and cheered on that sunny day in 1956. But a gloom has since descended on nuclear power. There’s the radioactive waste, the decommissioning and the accidents, from Chernobyl to Fukushima. As concern about climate change increased, nuclear’s one saving grace became that it is carbon free. But now, the cost of much renewable energy has fallen below that of nuclear. These days we produce little more power from nuclear than we did 20 years ago. So just as we need as much clean energy as we can get, it seems we are spurning our best developed source of it. Is it really time to call time on nuclear? The cheers around Calder Hall in 1956 had nothing on the spirit of optimism that surrounded the birth of nuclear power a decade earlier. Scientists had worked out that splitting heavy atoms released huge amounts of energy that could be used for more than just bombs. There was talk of everything from nuclear-powered moon shuttles to plutonium-heated swimming pools. Over 32 | NewScientist | 1 September 2018
the following two decades, nuclear reactors big enough to match a coal power station’s power output came online in more than 30 countries. Much of the technology’s bad rap today in Europe and the US centres on the mountains of waste those plants have since produced. Nuclear reactors typically bombard uranium with neutrons to induce an ongoing process of fission, where the uranium atoms split into smaller pieces, releasing lots of heat. That heat is used to generate electricity, with highly radioactive elements leftover. There might be new ways of dealing with the waste (see “Trash to treasure”, right), although there still remain the huge costs, spread over decades, associated with decommissioning the reactor itself. But other developments are making the economics of nuclear power look extremely shaky. The cost of electricity is generally quoted per megawatt-hour (MWh), with 1 MWh being roughly the power a tumble dryer uses in a year. The UK government has guaranteed that the owners of Hinkley Point C nuclear power station, whose construction has begun in Somerset, will be able to sell their electricity for £92.50 per MWh. Meanwhile, some onshore wind turbines are being commissioned on the assumption that they will sell their energy at about £30 per MWh. >
The power plants at Tihange will close as Belgium phases out nuclear energy
INDUSTRYANDTRAVEL / ALAMY STOCK PHOTO
TRASH TO TREASURE As bugbears go, nuclear waste is a big one. The trouble is, it remains dangerous for so long. Even thousands of years from now, exposure will cause radiation sickness, which means skin rashes, vomiting and death, depending on the dose. In the early days, we dumped barrels of waste in old mines. Then we realised these places can become swamped in groundwater, which risks carrying radioactive material back to the surface. The latest ploy is to stuff it deep below ground in places where no water can get at it. Encased in concrete, nuclear waste can be stored in these deep geological repositories for generations. This is the “best available technology” backed by an “international consensus”, says Neil Hyatt at the University of Sheffield, UK. Could we do better? Hyatt is investigating bespoke materials into which the radioactive material can be mixed instead of concrete. He takes different ceramics and bombards them with lots of radiation to simulate how they will cope far into the future. “You drive the material to become amorphous in a matter of hours,” says Hyatt. He has recently shown that materials based on calcium, zirconium, titanium and oxygen perform well. Even better, why not harness the power of the radioactive waste rather than hide it away? That’s the goal of an approach called transmutation. The idea is to take the heavy elements such as plutonium — by far the longest-lived kind of radioactive waste — and bombard them with neutrons from a particle accelerator. That splits the nuclei into less hazardous chemicals that are only dangerously radioactive for about 100 years. It also releases energy, so is a way of getting more out of the waste. The idea has never quite come off, largely because the heavy nuclei must be separated from the rest of the waste for it to work. But in 2017, researchers at the Tokyo Institute of Technology reported that the need for separation can be avoided by instead using a moderator that slows down the release of neutrons, allowing the unseparated waste to absorb them better. Perfect that process and we won’t need to hide our nuclear waste anymore. 1 September 2018 | NewScientist | 33
Nuclear come down Despite all its costs, nuclear is still cheaper than some common energy sources. But the cheapest renewables do undercut it
After quick growth in the 1970s and 80s, the amount of power produced by nuclear plants has fallen over the past decade 3000
Coal, with carbon capture and storage
2500
TWh
2000 1500
Asia
Offshore wind
South America
Nuclear (pressurised water reactor)
North America
East Europe and Russia
Large-scale solar PV
63
West and central Europe
Onshore wind
61
SOURCE: WORLD NUCLEAR ASSOCIATION,IAEA POWER REACTOR INFORMATION SERVICE (PRIS)
These economics are part of the reason why, after decades of growth, installed nuclear capacity around the world has plateaued since around 2000, even falling in some places as nuclear plants reach the end of their lives and few new ones are built (see chart, above). Belgium, Germany, Switzerland and Spain have all committed themselves to phasing out nuclear power entirely. In July, the UK government’s independent advisers on infrastructure trashed nuclear power, arguing that investing in renewables is cheaper. “The cost coming down so quickly on renewables means you may have a limited window for strong growth for nuclear power,” says Brent Wanner at the International Energy Agency. But renewables are not without their drawbacks. In June and July, the UK experienced a wind drought, where wind power was down 40 per cent compared with the same period a year earlier despite there being more turbines. True, such niggles may be solved with better batteries or other methods of storing power. But even then, renewables may not be as cheap as they appear on paper. Erecting enough solar panels or wind turbines to match the output of a nuclear plant would take up vast tracts of land. They also only last around 25 years, rather than the 60 or more offered by atom-smashers. Plus, turbines need to be decommissioned, just as nuclear plants do. A recent UK government report estimated the cost of decommissioning the 37 offshore wind farms being built or already operating across the country. It put 34 | NewScientist | 1 September 2018
95
Gas, based on a closed-cycle turbine
20 16
20 12
20 08
20 04
20 00
19 96
19 92
19 88
19 84
19 80
19 76
19 72
0
100
Africa
1000 500
136
the price of removing all the infrastructure associated with the turbines, such as concrete moorings, at up to £3.6 billion. In other words, energy cost statistics can obscure more than they reveal. There are efforts to produce “levelised costs”, which account for as many variables as possible, including, say, the cost of planning infrastructure. The UK government’s latest such figures show that the cost of offshore wind and nuclear are similar (see chart, above right). Onshore wind is much cheaper, but it faces roadblocks in the shape of restricted access to land and limited community support.
“The time taken to build a nuclear plant has doubled over the past 50 years” There is hope that advanced nuclear reactors might be better value. Take the EPR reactor design, which should produce the same power from 17 per cent less uranium compared with a mid-class pressurised water reactor, one of the most common types. Yet it is a long-term goal. The technology needs financial help to get up and running. Hinkley Point C, which will feature a pair of EPR reactors, is a case in point. There are only a handful of other EPR plants being built globally, the first of which, in China, was connected to the grid at the end of June. But construction of that plant, known as Taishan 1, began almost a decade ago. That
G_Nuclear comeback
82
Whole-lifetime costs of energy, assuming commissioning in 2025 (£/MWh) SOURCE: DEPARTMENT FOR BUSINESS, ENERGY AND INDUSTRIAL STRATEGY, 2016
speaks of the real problem with nuclear plants, as uncovered in a study from Joana PortugalPereira at Imperial College London and her colleagues. They compiled a database of nuclear reactors built between 1955 and 2016 and the costs involved in constructing them. They found the length of time taken to build new plants doubled over the past 50 years. Jacopo Buongiorno at the Massachusetts Institute of Technology and his colleagues have analysed why. It is not the materials or technologies themselves that are the problem. Each reactor is bespoke, and installation takes serious time and money, from digging the foundations and otherwise preparing the site to pouring the concrete. In principle, smaller and more uniform reactors should be cheaper. That’s the notion behind what are called small modular reactors or SMRs. They would be built to standardised designs and prefabricated before shipping around the world, making installation much more routine. The most-talked-about firm developing this technology is NuScale, headquartered in Oregon. Its design involves a jacket of water that circulates and cools an inner reactor by convection. This is simpler than relying on pumps to move the water and makes it easier to produce many copies of the reactor quickly and cheaply. NuScale has yet to build a working reactor, but it has passed the first and most challenging phase of a design certification review by the US Nuclear Regulatory Commission. Full approval may be granted
as soon as 2020. But because the firm won’t make any money from its reactors for years, it needs serious financial backing. What has plenty of people interested is that NuScale now has that backing. The US recently announced $60 million in federal funding for nuclear research and development and two‑thirds of that has gone to NuScale to help it finalise its designs.
The firm aims to have its first SMR running by 2026. In the meantime, it may be joined by another company with experience building nuclear reactors, Rolls-Royce. The company has traditionally produced these for military submarines, not civil projects, but says it is keen to develop SMRs for global export. Yet these are a long and uncertain game. One pro-nuclear think tank says they could eventually produce electricity for as little as £28 per MWh. However, the UK government’s estimates suggest that even by 2031 they will be a third more expensive than conventional nuclear. For Buongiorno, they also neglect an obvious innovation. If preparing the land for a reactor is the problematic part of nuclear power, well, just put them on the ocean. “We think an offshore concept can slash costs quite dramatically,” he says. In 2015, Buongiorno and his colleagues published their own idea for a floating nuclear plant, which would send electricity to shore along an undersea cable. Floating plants could take advantage of seawater for cooling.
WILL ROSE/GREENPEACE
Nuclear-on-sea
Having so much water around them would be particularly useful for cooling during an overheating accident. And the plants are already a reality. Russia launched the first purpose-built facility a few months ago and China has also expressed an interest in building its own fleet. Wanner reckons there is something in it. He agrees that floating plants could have more favourable economics than traditional designs. They offer portability too. Plants could be towed to remote communities or offshore engineering operations. They might even provide a zero-carbon way of supplying
URANIUM IN THE WATER Every year, some 67,000 tonnes of uranium is mined from the ground, most destined to fuel nuclear power stations. You might think that entails a lot of carbon emissions associated with the diggers. In fact, analyses suggest that is not much of a problem. Only about 1 gram of carbon dioxide is emitted per kilowatt-hour of energy generated. Even so, uranium mining has its downsides, sometimes allowing radioactive material to
seep into rivers. One long-considered alternative is to mine the stuff from seawater instead. Every 100,000 kilograms of ocean water holds 3 grams of uranium, meaning the seas have 500 times the amount known to exist on land. In 2017, Gary Gill and his colleagues at the Pacific Northwest National Laboratory in Washington set up an experiment to extract it. They submerged clumps of acrylic fibres in three tanks and pumped seawater through them for a
month. The fibres trapped a range of elements, including uranium. In June this year, they reported that they had managed to retrieve 5 grams of powdered uranium, known as yellowcake, the largest amount ever retrieved from seawater. Based on that, “we think we can produce it for about $250 per kilogram of uranium”, says Gill. That’s about five times the price of mined uranium, but Gill believes he can make his ocean-extracted variety competitive, given time.
This Russian floating nuclear power plant is set to support oil exploration in the Arctic
the power needed to install wind turbines. At first blush, floating nuclear might sound a terrible idea. What if radioactive material spilled into the ocean? Yet Buongiorno says the plants would enjoy “inherent protection” from earthquakes and tsunamis, the forces that caused the nuclear accident in Fukushima. And he says that, in principle, it is possible to design vessels that are resistant to deliberate attacks, including explosions and small torpedoes. But it would be possible to destroy the plant if an enemy tried hard enough. Julius Trajano at Nanyang Technological University in Singapore has also pointed out that it couldn’t access backup power in an emergency and a radioactive leak would be harder to contain. However safe and affordable nuclear power might become, the truth is that its public reputation is awful. And that might be the deciding factor, at least in Western countries. That is a key point for those prophesying the worldwide demise of nuclear. There are still 56 plants being built, nearly a third of them in China, with others planned in India and South Korea. The West may fret over whether nuclear can be reinvented as a small, cheap source of power. But elsewhere, the attraction of big atomic energy is still as great as on that sunny day in 1956. ■ Chris Baraniuk is a freelance science and technology journalist based in London 1 September 2018 | NewScientist | 35
Q
UEEN Elizabeth II climbed the five metal steps to the platform and spoke a few words into a microphone. She pulled a lever and the deed was done. A giant dial on a nearby building began to spin, as electricity sparked into life. She had just opened the UK’s first atomic power station, Calder Hall. The crowd clapped and cheered on that sunny day in 1956. But a gloom has since descended on nuclear power. There’s the radioactive waste, the decommissioning and the accidents, from Chernobyl to Fukushima. As concern about climate change increased, nuclear’s one saving grace became that it is carbon free. But now, the cost of much renewable energy has fallen below that of nuclear. These days we produce little more power from nuclear than we did 20 years ago. So just as we need as much clean energy as we can get, it seems we are spurning our best developed source of it. Is it really time to call time on nuclear? The cheers around Calder Hall in 1956 had nothing on the spirit of optimism that surrounded the birth of nuclear power a decade earlier. Scientists had worked out that splitting heavy atoms released huge amounts of energy that could be used for more than just bombs. There was talk of everything from nuclear-powered moon shuttles to plutonium-heated swimming pools. Over 32 | NewScientist | 1 September 2018
the following two decades, nuclear reactors big enough to match a coal power station’s power output came online in more than 30 countries. Much of the technology’s bad rap today in Europe and the US centres on the mountains of waste those plants have since produced. Nuclear reactors typically bombard uranium with neutrons to induce an ongoing process of fission, where the uranium atoms split into smaller pieces, releasing lots of heat. That heat is used to generate electricity, with highly radioactive elements leftover. There might be new ways of dealing with the waste (see “Trash to treasure”, right), although there still remain the huge costs, spread over decades, associated with decommissioning the reactor itself. But other developments are making the economics of nuclear power look extremely shaky. The cost of electricity is generally quoted per megawatt-hour (MWh), with 1 MWh being roughly the power a tumble dryer uses in a year. The UK government has guaranteed that the owners of Hinkley Point C nuclear power station, whose construction has begun in Somerset, will be able to sell their electricity for £92.50 per MWh. Meanwhile, some onshore wind turbines are being commissioned on the assumption that they will sell their energy at about £30 per MWh. >
The power plants at Tihange will close as Belgium phases out nuclear energy
INDUSTRYANDTRAVEL / ALAMY STOCK PHOTO
TRASH TO TREASURE As bugbears go, nuclear waste is a big one. The trouble is, it remains dangerous for so long. Even thousands of years from now, exposure will cause radiation sickness, which means skin rashes, vomiting and death, depending on the dose. In the early days, we dumped barrels of waste in old mines. Then we realised these places can become swamped in groundwater, which risks carrying radioactive material back to the surface. The latest ploy is to stuff it deep below ground in places where no water can get at it. Encased in concrete, nuclear waste can be stored in these deep geological repositories for generations. This is the “best available technology” backed by an “international consensus”, says Neil Hyatt at the University of Sheffield, UK. Could we do better? Hyatt is investigating bespoke materials into which the radioactive material can be mixed instead of concrete. He takes different ceramics and bombards them with lots of radiation to simulate how they will cope far into the future. “You drive the material to become amorphous in a matter of hours,” says Hyatt. He has recently shown that materials based on calcium, zirconium, titanium and oxygen perform well. Even better, why not harness the power of the radioactive waste rather than hide it away? That’s the goal of an approach called transmutation. The idea is to take the heavy elements such as plutonium — by far the longest-lived kind of radioactive waste — and bombard them with neutrons from a particle accelerator. That splits the nuclei into less hazardous chemicals that are only dangerously radioactive for about 100 years. It also releases energy, so is a way of getting more out of the waste. The idea has never quite come off, largely because the heavy nuclei must be separated from the rest of the waste for it to work. But in 2017, researchers at the Tokyo Institute of Technology reported that the need for separation can be avoided by instead using a moderator that slows down the release of neutrons, allowing the unseparated waste to absorb them better. Perfect that process and we won’t need to hide our nuclear waste anymore. 1 September 2018 | NewScientist | 33
Nuclear come down Despite all its costs, nuclear is still cheaper than some common energy sources. But the cheapest renewables do undercut it
After quick growth in the 1970s and 80s, the amount of power produced by nuclear plants has fallen over the past decade 3000
Coal, with carbon capture and storage
2500
TWh
2000 1500
Asia
Offshore wind
South America
Nuclear (pressurised water reactor)
North America
East Europe and Russia
Large-scale solar PV
63
West and central Europe
Onshore wind
61
SOURCE: WORLD NUCLEAR ASSOCIATION,IAEA POWER REACTOR INFORMATION SERVICE (PRIS)
These economics are part of the reason why, after decades of growth, installed nuclear capacity around the world has plateaued since around 2000, even falling in some places as nuclear plants reach the end of their lives and few new ones are built (see chart, above). Belgium, Germany, Switzerland and Spain have all committed themselves to phasing out nuclear power entirely. In July, the UK government’s independent advisers on infrastructure trashed nuclear power, arguing that investing in renewables is cheaper. “The cost coming down so quickly on renewables means you may have a limited window for strong growth for nuclear power,” says Brent Wanner at the International Energy Agency. But renewables are not without their drawbacks. In June and July, the UK experienced a wind drought, where wind power was down 40 per cent compared with the same period a year earlier despite there being more turbines. True, such niggles may be solved with better batteries or other methods of storing power. But even then, renewables may not be as cheap as they appear on paper. Erecting enough solar panels or wind turbines to match the output of a nuclear plant would take up vast tracts of land. They also only last around 25 years, rather than the 60 or more offered by atom-smashers. Plus, turbines need to be decommissioned, just as nuclear plants do. A recent UK government report estimated the cost of decommissioning the 37 offshore wind farms being built or already operating across the country. It put 34 | NewScientist | 1 September 2018
95
Gas, based on a closed-cycle turbine
20 16
20 12
20 08
20 04
20 00
19 96
19 92
19 88
19 84
19 80
19 76
19 72
0
100
Africa
1000 500
136
the price of removing all the infrastructure associated with the turbines, such as concrete moorings, at up to £3.6 billion. In other words, energy cost statistics can obscure more than they reveal. There are efforts to produce “levelised costs”, which account for as many variables as possible, including, say, the cost of planning infrastructure. The UK government’s latest such figures show that the cost of offshore wind and nuclear are similar (see chart, above right). Onshore wind is much cheaper, but it faces roadblocks in the shape of restricted access to land and limited community support.
“The time taken to build a nuclear plant has doubled over the past 50 years” There is hope that advanced nuclear reactors might be better value. Take the EPR reactor design, which should produce the same power from 17 per cent less uranium compared with a mid-class pressurised water reactor, one of the most common types. Yet it is a long-term goal. The technology needs financial help to get up and running. Hinkley Point C, which will feature a pair of EPR reactors, is a case in point. There are only a handful of other EPR plants being built globally, the first of which, in China, was connected to the grid at the end of June. But construction of that plant, known as Taishan 1, began almost a decade ago. That
G_Nuclear comeback
82
Whole-lifetime costs of energy, assuming commissioning in 2025 (£/MWh) SOURCE: DEPARTMENT FOR BUSINESS, ENERGY AND INDUSTRIAL STRATEGY, 2016
speaks of the real problem with nuclear plants, as uncovered in a study from Joana PortugalPereira at Imperial College London and her colleagues. They compiled a database of nuclear reactors built between 1955 and 2016 and the costs involved in constructing them. They found the length of time taken to build new plants doubled over the past 50 years. Jacopo Buongiorno at the Massachusetts Institute of Technology and his colleagues have analysed why. It is not the materials or technologies themselves that are the problem. Each reactor is bespoke, and installation takes serious time and money, from digging the foundations and otherwise preparing the site to pouring the concrete. In principle, smaller and more uniform reactors should be cheaper. That’s the notion behind what are called small modular reactors or SMRs. They would be built to standardised designs and prefabricated before shipping around the world, making installation much more routine. The most-talked-about firm developing this technology is NuScale, headquartered in Oregon. Its design involves a jacket of water that circulates and cools an inner reactor by convection. This is simpler than relying on pumps to move the water and makes it easier to produce many copies of the reactor quickly and cheaply. NuScale has yet to build a working reactor, but it has passed the first and most challenging phase of a design certification review by the US Nuclear Regulatory Commission. Full approval may be granted
as soon as 2020. But because the firm won’t make any money from its reactors for years, it needs serious financial backing. What has plenty of people interested is that NuScale now has that backing. The US recently announced $60 million in federal funding for nuclear research and development and two‑thirds of that has gone to NuScale to help it finalise its designs.
The firm aims to have its first SMR running by 2026. In the meantime, it may be joined by another company with experience building nuclear reactors, Rolls-Royce. The company has traditionally produced these for military submarines, not civil projects, but says it is keen to develop SMRs for global export. Yet these are a long and uncertain game. One pro-nuclear think tank says they could eventually produce electricity for as little as £28 per MWh. However, the UK government’s estimates suggest that even by 2031 they will be a third more expensive than conventional nuclear. For Buongiorno, they also neglect an obvious innovation. If preparing the land for a reactor is the problematic part of nuclear power, well, just put them on the ocean. “We think an offshore concept can slash costs quite dramatically,” he says. In 2015, Buongiorno and his colleagues published their own idea for a floating nuclear plant, which would send electricity to shore along an undersea cable. Floating plants could take advantage of seawater for cooling.
WILL ROSE/GREENPEACE
Nuclear-on-sea
Having so much water around them would be particularly useful for cooling during an overheating accident. And the plants are already a reality. Russia launched the first purpose-built facility a few months ago and China has also expressed an interest in building its own fleet. Wanner reckons there is something in it. He agrees that floating plants could have more favourable economics than traditional designs. They offer portability too. Plants could be towed to remote communities or offshore engineering operations. They might even provide a zero-carbon way of supplying
URANIUM IN THE WATER Every year, some 67,000 tonnes of uranium is mined from the ground, most destined to fuel nuclear power stations. You might think that entails a lot of carbon emissions associated with the diggers. In fact, analyses suggest that is not much of a problem. Only about 1 gram of carbon dioxide is emitted per kilowatt-hour of energy generated. Even so, uranium mining has its downsides, sometimes allowing radioactive material to
seep into rivers. One long-considered alternative is to mine the stuff from seawater instead. Every 100,000 kilograms of ocean water holds 3 grams of uranium, meaning the seas have 500 times the amount known to exist on land. In 2017, Gary Gill and his colleagues at the Pacific Northwest National Laboratory in Washington set up an experiment to extract it. They submerged clumps of acrylic fibres in three tanks and pumped seawater through them for a
month. The fibres trapped a range of elements, including uranium. In June this year, they reported that they had managed to retrieve 5 grams of powdered uranium, known as yellowcake, the largest amount ever retrieved from seawater. Based on that, “we think we can produce it for about $250 per kilogram of uranium”, says Gill. That’s about five times the price of mined uranium, but Gill believes he can make his ocean-extracted variety competitive, given time.
This Russian floating nuclear power plant is set to support oil exploration in the Arctic
the power needed to install wind turbines. At first blush, floating nuclear might sound a terrible idea. What if radioactive material spilled into the ocean? Yet Buongiorno says the plants would enjoy “inherent protection” from earthquakes and tsunamis, the forces that caused the nuclear accident in Fukushima. And he says that, in principle, it is possible to design vessels that are resistant to deliberate attacks, including explosions and small torpedoes. But it would be possible to destroy the plant if an enemy tried hard enough. Julius Trajano at Nanyang Technological University in Singapore has also pointed out that it couldn’t access backup power in an emergency and a radioactive leak would be harder to contain. However safe and affordable nuclear power might become, the truth is that its public reputation is awful. And that might be the deciding factor, at least in Western countries. That is a key point for those prophesying the worldwide demise of nuclear. There are still 56 plants being built, nearly a third of them in China, with others planned in India and South Korea. The West may fret over whether nuclear can be reinvented as a small, cheap source of power. But elsewhere, the attraction of big atomic energy is still as great as on that sunny day in 1956. ■ Chris Baraniuk is a freelance science and technology journalist based in London 1 September 2018 | NewScientist | 35