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Posted in March 2011

A nuclear third way

This article by Julian Hunt and Graham O’Connor first appeared in The International Herald Tribune on Friday, March 25, 2011

Lord Hunt is a former fusion technology researcher, and a visiting professor at Delft University of Technology in the Netherlands. Graham O’Connor is a former senior scientist at the ITER (International Thermonuclear Experimental Reactor) project in France.

Nuclear power is here to stay, and the debate over its future should include ‘hybrid’ reactors.

The Fukushima disaster has inevitably prompted concern in many countries about nuclear power. But are the correct questions being asked?

A danger in the debate is that nuclear is often portrayed as a single, undifferentiated energy source. This is not only wrong, but also risks losing the opportunity we have to debate the role that new technologies – not only of fusion and fission, but also hybrid methods – can play in the energy mix in the 21st century.

Indeed, those who seek to write nuclear off completely are missing what could be extraordinary, breakthrough developments on the horizon with hybrid technologies that might – relatively shortly – completely reshape the way we think about nuclear energy.

The starting point for debate, for friends and foe of nuclear alike, should be the daunting energy problems many governments face. With growing challenges to energy security, the range of energy sources must be broadened, with greenhouse gas emissions reduced because of global warming. There is also a pressing need to reduce air, water and land pollution by coal and oil extraction and combustion (which continue to cause more deaths per year than nuclear power has in its entire history).

Renewables are a key part of the solution, but no country can be sure of the reliability of energies such as wind or solar in 20 to 50 years, given changed climatic conditions. Relying on neighboring countries for power also carries risks.

There seems to be no alternative but to include nuclear in the energy mix for at least decades to come. So, what do new generations of fission, fusion and hybrid offer?

• Fission
Modern power stations using fission, which harnesses energy from the radioactive decay of uranium and other fissile materials, are considerably safer than older ones such as Fukushima – constructed 30-40 years ago. This is because of stronger containment structures, more secure storage of spent fuel rods and emergency systems to prevent overheating. Further developments over the next 20 years will also reduce volumes of radioactive waste.

Because the supply of uranium may be limited, there are longer-term, controversial plans in some countries to construct ”fast breeder” reactors to recycle waste and use the fuel more efficiently. However, there are proliferation dangers associated with the plutonium byproduct.

Fission will only continue to be acceptable if the immediate risks of the current and planned systems are reduced. Despite improved safety, the rare, but catastrophic failures of technological and human operations such as Chernobyl cannot be dismissed. As Fukushima showed, there are also remaining risks from earthquakes, tsunamis, severe storms and even aircraft crashes – plus the dangers of fission associated with the storage of waste for over 10,000 years in geological repositories.

• Fusion
The principle of controlled thermonuclear fusion is to extract energy from processes similar to those occurring inside the Sun, where hydrogen atoms are fused together to form helium. This is a ”clean” process with negligible long-lived radioactive waste.

However, because of the great size needed for a ”pure” fusion reactor and the unsolved problem of fabricating materials to withstand the heat, the development challenges are substantial and may take decades to overcome.

• Hybrid
The long-term future of nuclear may lie with a still-little-known third option: combining nuclear fission (atoms splitting) and fusion (atoms merging) in a single ”hybrid” reactor. Indeed, without publicity, governments, agencies and research institutes are already moving tentatively in this direction.

Hybrid fusion was first proposed by the American Nobel laureate Hans Bethe to enable more widely available reserves of nuclear fuels other than uranium, such as thorium, to be used. Hybrid could become a reality within the next two decades – the Institute of Plasma Physics in China is planning to build a proof-of-principle prototype experiment by 2025.

The basic principle is that neutrons generated by fusion in the plasma core stimulate fission in the outer ”blanket” that contains uranium or other fissile materials (which could include nuclear waste). Because there is relatively less energy extracted from the plasma than in pure fusion, continuous operation can be engineered more readily.

The fission is well below critical mass and only operates when there is a current flowing in the plasma. This is why the system is safer.

The technology of maintaining the hybrid reactors has many advantages, and it uses a wider range of fuels. They do not produce the long-lived waste produced in fission because the high-energy neutron flux from the fusion process ”transmutates” these into isotopes that decay over a hundred rather than tens of thousands of years.

Not only does this eliminate some nuclear waste problems; it helps to rid the world of plutonium and other weapons-grade materials. Furthermore, if thorium is used, it cannot be converted into weapons-grade uranium.

While even modest-sized hybrid reactors could provide affordable and almost limitless energy, their power output can be controlled through the fusion process. Thus the operation is safe enough for a power station to be located even in countries prone to natural hazards.

Furthermore, the controllability would allow fusion-fission power to be used either as base load or more flexibly in combination with renewable energy, which is inherently more variable.

Many aspects of hybrid nuclear require further intense research – and economic analysis. Current collaboration between groups in Russia, China, the United States, South Korea and Britain needs to involve more countries.

While workable hybrid technology is still some way off, timeframes could be accelerated with the right commitments from the public and private sector.

This ”third nuclear way” deserves much wider understanding and support from governments, scientists, engineers and environmentalists alike if we are going to have the maturity of debate we so badly need about the role that nuclear can play in the energy mix over decades to come.

Domino-effect Japan kan ook in Nederland voorkomen

Dit artikel verscheen op WaterForum op 22 maart 2011

De gevolgen van de tsunami in Japan strekken zich uit tot ver buiten het getroffen gebied en treffen kerncentrales en de nationale energievoorziening en economie. Ook bij een watersnood en andere grote rampen in Nederland zijn zulke keteneffecten te verwachten, stellen onderzoekers Bas Jonkman (TU Delft/University of California, Berkeley) en Ties Rijcken (TU Delft).

Lees verder op de site van WaterForum.

Update 28 maart: Ook Cobouw besteedde aandacht aan dit onderwerp: ‘Effecten tsunami kunnen ook in Nederland voorkomen’

Japan and the Next Step for Disaster Preparedness

Modern technology saved thousands of lives Friday. Now we need to improve care for urban survivors.

This article by Julian Hunt and Simon Day appeared in the Wall Street Journal on Monday, March 14, 2011. Lord Hunt is visiting professor at Delft University of Technology and former director-general of the UK Met Office. Mr. Day is a researcher at the Aon Benfield Hazard Research Centre at University College London.

The 8.9 magnitude earthquake that struck Japan on Friday is the largest to hit the country in recorded history. It has numerous similarities, in both type and scale, to the 8.5 magnitude quake which struck Japan in 1896. Around 27,000 people are estimated to have been killed by that quake and the subsequent tsunami, which was some 25 meters high. In this case, the death toll could far exceed 1,000, most of those victims to the tsunami.

While that toll is tragically high, it is worth noting the scientific, technological and institutional developments that will have kept Friday’s earthquake and tsunami from claiming as many victims as previous disasters did. We now have a better understanding of the linkage between geophysical processes and detection technology, and have improved the education of, and communication to, at-risk communities.

All this is an undeniable mercy in allowing so many more people to survive such disasters than would have been possible before. But it also poses a new challenge for policy makers, one that came into focus over the weekend in Japan and that ought to be on the minds of disaster planners elsewhere: how best to care for hundreds of thousands, or even millions, of survivors who are dislocated by a severe natural disaster.

Japan shows how complex this question has become. Providing drinking water, food and shelter to those affected has become a major logistical challenge. Hundreds of thousands of Tokyo residents who live miles away from their houses and depend on modern urban transportation systems to get home each evening found themselves stuck in office buildings ill equipped to handle them.

This is a significant consequence of modern urbanization. The proportion of the world’s population living in urban areas is expected to reach between 60% and 70% later this century, from around 50% now. Japan is the epitome of this: Only 5% of the population works in agriculture (a proxy for rural residence), and around 80 million of Japan’s 127 million people are concentrated on the Pacific shore of Honshu island—the region that includes Tokyo.

Simultaneously, there is a movement toward very large cities with populations exceeding one million. In 1950, there were only 83 cities in the world of such a size, whereas this number had risen to 468 by 2007. There are now some 21 "mega cities" of greater than 10 million inhabitants—Tokyo is one of those.

The high concentration of people per square meter in urban areas, anywhere from 100 to 1,000 times the global average, can make populations more vulnerable to extreme natural hazards ranging from earthquakes to heat waves and floods. Even a localized disaster in a city can affect exponentially more people than a disaster hitting a similar land area in the countryside; the effect is magnified further for a region-wide disaster such as Friday’s earthquake.

The growing size of many urban areas also means that people sometimes cannot physically escape in the event of extreme hazards, as recent hurricanes and tsunamis in the United States and Indonesia have shown. Where attempts have been made to evacuate multi-million populations, lives have sometimes been lost in the transport systems as they seized up.

This means policy makers and architects face the question of how to provide refuge for those people during and after a disaster, and how those refuges should be integrated into the design of structures. The problem is much more difficult than simply building a bunker in the basement. Refuges have different roles for different types of disaster. For tsunamis, a shelter is usually only needed for a short period, as with high winds, tropical cyclones and landslides. For longer lasting disasters, such as volcanic eruptions, people have longer warning, and behave differently (for instance, bringing goods and even animals to the shelters in rural areas).

Regulators and engineers are only starting to grapple with this kind of question, but already some points are clear. Increasingly, communities in urban areas will have to understand and be prepared for risks of hazards and need to be involved in addressing them, in partnership with local and national government. This will involve training communities to deal with a range of potential natural disasters relevant to their local areas.

Structural engineers, planners and social scientists will also need to consider more urgently the design of appropriate shelters in urban and also in rural areas (for instance, parks and open areas may also act as refuges). This will require intensive study and resources to ensure good design and effectiveness. Careful study of unfolding events in Japan could help this effort over the long run.

The complexity of policies that are needed for dealing with these issues may be hard to envisage, and even harder to carry out. However, change is urgently needed and the longer we wait, the harder it will become to achieve and the more lives that will be lost.

© 2011 TU Delft