NUCLEAR FUSION DREAM MAKES A GREAT LEAP

Since mid-’50s, nuclear fusion (the same process that powers the stars) has allowed the dream of clean and virtually limitless energy, fuelled by two easily available forms of hydrogen, and producing almost no radioactive waste and no emissions of greenhouse gases. That would save a world threatened by climate change and an expected three-fold increase in global energy demand. However, it has always presented huge technical challenges, such as the management of a massive infrastructure or the design of ways of extracting net energy from it. Despite this, nuclear fusion benefits are so vast that it’s no wonder that scientists have spent half a century (and billions of dollars) into developing the right technology.

An important leap forward was made a week ago when researchers with the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, in California, announced that they reached a long-sought milestone. For the first time, the fuel used to trigger fusion in their reactor was capable of producing more energy than required to initiate fusion. This work, published in Nature magazine, crosses a crucial threshold on the ongoing pursuit toward wielding the power of nuclear fusion. Although the experiment did not yield a big amount of energy (around 1%), it brings us one step closer to a controlled and sustainable fusion reaction.

The nuclear power plants around the world today use fission, which works by splitting heavy atoms (such as those of uranium) and extracting the energy released. On the contrary, nuclear fusion produces a big deal of energy by “joining” two light atoms (hydrogen) together. This reaction takes place every day in the stars and the Sun which, deep at their core, contain a natural fusion reactor. Indeed, one of the challenges that makes fusion extremely difficult to control is the harnessing of the plasma that this process generates, as it reaches temperatures of millions of degrees.

The Livermore reactor is complex, and the way it works can be summarized into two fundamental steps:

1. Approaching hydrogen atoms: The two forms of the hydrogen fuel (deuterium and tritium) sit inside a plastic pellet in a cylinder. A huge amount of energy must be injected into the fuel to drive the hydrogen nuclei close together to overcome the electrical repulsion that keeps them apart. At the Livermore reactor this energy is provided by 192 laser beams.

2. Trying to trigger ignition: The lasers then heat up the cylinder, which re-emits the energy as X-rays. That causes the outer plastic shell to explode, raising the density of the fuel inside high enough to trigger fusion. The more energy the hydrogen atoms receive, the more fusion happens, and, ultimately, a chain reaction takes place and the fusion becomes self-sustaining. This is known as ignition. Although scientists have not yet achieved ignition (because only a very small amount of the laser’s power makes it to the hydrogen atoms), this work details how to obtain a net gain of energy within the fuel itself, which is a very important step on the way to ignition.

Plenty of work still remains for fusion researchers. According to them, only 1/200th of the energy that the lasers generate is delivered to the hydrogen fuel, which is not enough to set off a chain reaction. In that sense, scientists have to time their laser pulses to give the hydrogen the right kick. Moreover, scientists found it was extremely difficult to generate the right pressure and temperatures inside the hydrogen gas required for fusion. In order to do so, the plastic shell has to collapse perfectly symmetrically, and its design should be flawless.

The most ambitious scientific venture ever is starting to look more possible. The international nuclear fusion project, known as ITER, under construction in France, will also attempt to generate fusion energy by trapping the hydrogen plasma in a donut-shaped magnetic chamber (a completely different approach than what has been achieved at Livermore laboratories). Meanwhile, the NIF team is cautiously optimistic of their achievements and future prospects. Fusion-energy generation still remains a distant goal (first commercial nuclear fusion power plants are expected for 2050s), but it has never been worked on so enthusiastically.

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source: https://lasers.llnl.gov/science/energy-for-the-future

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NUCLEAR POWER TO FIGHT CLIMATE CHANGE

If four of the world’s top climate and energy scientists gather to write an open letter, this letter should attract considerable attention and interest. But if this letter calls on world leaders to support development of safer nuclear power systems, then it should immediately be a worldwide priority.

The letter, signed by climatologist James Hansen, atmospheric scientist Ken Caldeira, meteorologist Kerry Emanuel and climate scientist Tom Wigley, is addressed “to those influencing environmental policy but opposed to nuclear power”. The four scientists wrote that the “continued opposition to nuclear power threatens humanity’s ability to avoid dangerous climate change […] there is no credible path to climate stabilization that does not include a substantial role for nuclear power”. It is noteworthy that one signer, Ken Caldeira, now a distinguished climatologist, was arrested during the 1979 anti-nuclear protest that emerged after the famous Three Mile Island accident in the USA.

Probably the biggest problem our generation will face in the near future is that we are running out of petroleum, we can’t even regulate its cost but, on the contrary, we are absolutely dependent on it. At the same time it is urgent to considerably reduce greenhouse gas emissions. The world needs to manage the growing global energy demand without using the atmosphere as a waste dump. However, although fossil fuels are the main and direct cause of global warming they are, by far, less frowned upon than atomic power in society.

The letter exposes scientific arguments in favour of nuclear power in clear and straightforward language. The authors don’t hide its risks (“we understand that today’s nuclear plants are far from perfect…”) but say those are much smaller than the risk of an extreme climate change. They point to developments, such as new safety systems or modern technology to solve the waste disposal problem to make new power plants safer and even cheaper than existing ones. However, they stress the importance of financial encouragement to make nuclear energy socially beneficial.

What about renewable energies? Ecologists agree that global warming is a threat to earth and humans, but many are against atomic power and believe that new forms of renewable energy will be able to supply the energy the world needs within the next few decades. The signers aren’t opposed to renewable energy sources, but want environmentalists to understand that “realistically, they cannot on their own solve the world’s energy problems”. I agree.

In conclusion, from my perspective this letter is a breath of fresh air for people not limited to simply oppose fossil fuels and promote renewable energy. The problem of energy is too important to be left to emotions that absolutely do not correspond to 21st century nuclear technology. We need facts, and this letter definitely can help realize people about the difficult choices that climate change presents us.

Imatge

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DOES ANYONE UNDERSTAND THE QUANTUM THEORY?

Niels Bohr, one of the fathers of the quantum theory, said in 1922: “If quantum mechanics hasn’t profoundly shocked you, then you haven’t understood it”. And I would add here: Even if you found it disconcerting, you probably didn’t understand it either. This statement can be extended to scientists working in the field as well. Richard Feynman quoted: “I can safely say that nobody understands quantum mechanics”.

The situation hasn’t essentially changed since Feynman’s time, but the question has become more dramatic. The quantum theory was developed at the start of the twentieth century; it has changed enormously the scientific view on nature, the life of many generations and will likely continue to do so in the future. Around the 30% of the gross world product depends on our limited comprehension of quantum mechanics; wherever there is a transistor, a magnetic resonance, a computer or a laser, there will be the quantum theory behind. And yet the strange thing is that we have no clue how any of its fundamental principles (tunnel effect, wave-particle duality, the Copenhagen interpretation…) actually work. Ask a bunch of physicists about the meaning of the quantum theory; their answers will probably display little consensus.

For more than 100 years most physicists and chemists have used quantum mechanics to calculate with incredible precision many different phenomena, but nobody has successfully explained where it comes from. The quantum world continues to be an imaginary world that defies logical sense, a place where anything can happen, and it raises all kinds of weird questions that push the limits of our imagination. It tries to convince us, for example, that objects like electrons exist simultaneously in two places at the same time. That’s why, for some researchers, quantum theory issues are not truly scientific questions that can be analysed by experiment, but philosophical ones that might depend on personal preference.

Quantum mechanics perturbed Einstein so much that he refused to accept it during many years of his life. When the fathers of the quantum theory (Bohr, Heisenberg, Schrödinger…) came up with a description of the quantum world in which certainties were replaced by mere probabilities, Einstein protested with his very famous quote: “God does not play dice”. Einstein may have gone wrong with his particular approach, but he was right in feeling a resolved sense of anxiety regarding the reality which the quantum world encloses. Perhaps he couldn’t bear the feeling that one of the most successful theories of history is, at its deepest level, a complete mystery.

Maybe our mistake is in trying to use everyday common sense to explain an unworldly universe that simply cannot be encapsulated in our finite minds. It’s been said that, as a quantum physicist or chemist, you don’t ever come to understand the quantum universe in any intuitive sense; you just get used to accepting it. In the words of physicist David Mermin, scientists should continue to “shut up and calculate” and give appropriate explanations of the unbelievable agreement with experiment data that the theory provides us. Because, once you accept its weirdness, quantum theory becomes a fantastically useful tool. 

Imatge

 

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HOW CAN CHEMISTS SELL CHEMISTRY TO SOCIETY?

The progress of mankind in the last 150-200 years, extremely much higher than in the previous 5000 years, is thanks in large part to chemistry. Over these last 200 years the chemical industry has absolutely transformed human life. The products of chemistry underlie the very base of modern civilization. No one can imagine aircrafts without alloys, medicine without drugs, crops without fertilisers or any plastic-made artefact without plastics. And yet chemists have to deal with an increasingly distrustful society whose reactions to chemistry range from suspicious to neurotic.

The main problem is that almost any criticism of chemical technology relies on emotions, and if there is one thing we have learnt from marketing is that is much easier to sell emotions than facts. Emotions and fear come out of the usual fear of the unknown, of things that don’t make intuitive sense. Primary and high school offer only a superficial venture into chemistry and in college, unless you study chemistry or a related degree, there is only some limited approach to the field.

The media in all of its forms (bloggers, journalists, filmmakers…) know how to exploit this and only report on the negative aspects of chemistry and chemicals, greatly skewing the danger presented by chemicals. Statistics, context and objective evidence are often neglected while anecdotal data and generalizations always rule. An example is the introduction of nonsensical terms like “chemical-free” or “eco-friendly” to suggest a product is safer or better in some way. The word “chemical” has begun to take on the meaning toxic and synthetic, and that’s what public read it as. In that sense, chemistry needs more journalists talking about it in a constructive, disinterested and “non-populistic” way. Good chemistry journalism should transmit the fact that, on balance, chemistry has done much more good than harm.

Imatge

It’s difficult to counter misunderstandings about chemistry, especially if we consider that we are fighting emotions with evidence. Here are some hints on what we, the chemists, can do about this issue:

1. First of all, and very important, chemists in particular need to be critical of chemicals too. No one else understands better their bad side-effects and benefits; thus, we have to be vocal critics on the safety of drugs, food additives and any sort of chemistry-made material.

2. For the same reason, chemists should be first to talk to scientists and organisations that are not being honest in their interactions with society. Those with scientific expertise certainly have a better capacity to do this than do non-scientists.

3. Chemists should not act in a defensive way when an anti-chemistry point is made. They need to join in the debate, ask questions and find out where/how the other person got their information and why they are concerned.

4. And finally, chemists should not try to convert everyone to be a chemist. This means it doesn’t help to lecture people about chemistry. Instead, their aim should be to provide people with the basic skills and tools, so they can make their own judgements.

Whatever the strategy, it’s crucial that we’re intelligent about the way we navigate our chemical world. There is no doubt that fighting against chemical superstition will be a permanent concern for chemists in the future.

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NUCLEAR POWER: FROM MARIE CURIE TO ANGELA MERKEL

The Fukushima disaster in 2011 turned the German people against nuclear energy, and chancellor Angela Merkel immediately announced the shuttering of all the reactors by about 2022 or 2023 (quite before their life expectancy). In any case, Germany is ending its nuclear era and changing deeply a structure that has developed over more than 100 years.

It all began February 26, 1896. French physicist Antoine Henri Becquerel was interested in the phenomenon of fluorescence, in which some materials glow when exposed to sunlight. Physicist Wilhelm Röntgen had recently discovered X-rays; He found that, when exposing a fluorescing material (an uranium compound called potassium uranyl sulfate) to the sun, it emitted invisible spontaneous radiation, capable of passing through opaque objects, the same as X-rays. He called this radiation radioactivity. The mechanism of this phenomenon was studied more profoundly between 1898 and 1902 by Pierre Curie and Marie Slodovska, a Polish and naturalized-French physicist and chemist that took up her husband’s name. In 1903, for their work, Marie Curie, her husband Pierre, and Henry Becquerel, were awarded the Nobel Prize for Physics. However, the work of Marie Curie with radioactivity was done in ignorance of its effect on human health. She and her daughter Irene died from leukaemia induced by exposure to high levels of radioactivity.

Ernest Rutherford established in 1911 that radioactivity depended on the atomic nucleus. Two years later, Niels Bohr proposed the atomic model that nowadays seems to us so intuitive: The negatively charged electrons confined to an atomic shell that encircles a positively charged atomic nucleus (made of protons and neutrons). Meanwhile Max Planck, Albert Einstein and Wolfgang Pauli formulated the theory (quantum mechanics) that would cast some light on these stunning breakthroughs. In the 1930s, Enrico Fermi and Otto Hahn carried out experiments where heavy elements, such as uranium, were bombarded with neutrons and split into lighter atoms, realizing huge amounts of energy. By 1935 the two men had already discovered slow neutrons, which have properties important to the operation of nuclear reactors. The artificially induced nuclear fission was born.  

In the beginning of the 40s, Hitler criticized what he called the “Jewish physics”. He drove Fermi, Einstein, Pauli Bohr and many other scientists into exile. They ended up participating, directly or indirectly, in the invention of the atomic bomb, in the so-called Manhattan Project, headed by Robert Oppenheimer. Planck and Hahn rested in Germany and fell under suspicion. And others, such as Werner Heisenberg, collaborated in the failed development of a German nuclear reactor. Electricity generation from nuclear power was finally achieved in 1951.

How did Einstein, Bohr, Heisenberg or Oppenheimer see the role of the emerging technoscientific knowledge? What would have been their opinion nowadays on the nuclear “affair”? More important, which is our position concerning atomic power? Critics argue Merkel’s decision was emotional, not practical. I agree. However, it might be true that the nuclear fission era has finally come to an end. It’s time to direct our efforts towards the establishment of nuclear fusionImatge

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THE PURSUIT OF THE PERFECT CATALYST

Catalysis provides powerful tools for efficiently and selectively making/breaking chemical bonds, which is essential for converting raw materials (basic chemicals) into useful products for society in an eco-friendly fashion. Despite the huge developments of catalysis in the past few decades, there are still many challenges ahead.

Many chemical transformations rely on valuable metals like palladium, platinum, ruthenium or rhodium as catalysts. But such metals are rare, expensive and sometimes toxic. This is why, for years, scientists have dedicated many efforts to develop methods of catalysis using cheap, earth-abundant and non-polluting metals like iron, copper or cobalt. It is not easy, especially if we consider that catalysts based on precious metals have enabled highly selective synthesis of a wide range of chemicals.

In the recent years separate teams of researchers have developed catalysts based on cheap metals that can perform impressive reactions traditionally based on earth-scarce and precious metals. For example, in one study, University of Girona researchers showed that common, environmentally benign iron complexes catalyse water oxidation to give O2 and H2. Water oxidation catalysis is crucial for the development of clean and abundant energy vectors such as hydrogen fuel cells based on sunlight. In another investigation, University of Toronto researchers developed an iron catalyst that efficiently mediates the production of alcohols and amines. These chemical compounds are ubiquitous in perfumes and medications.

The highly effective catalysis by nature’s enzymes has inspired scientists to imitate it. A proper understanding of how enzymes (nature’s catalysts) work holds out the promise of artificial catalysts for virtually any organic reaction of interest. Enzymes are more than just highly evolved catalysts: They display extremely high selectivity and are capable of increasing reaction velocities up to 1010 times. Moreover, biocatalytic reactions are usually carried out under physiological conditions, that is, at a temperature not higher than 36ºC, neutral pH and atmospheric pressure. Last but not least, enzyme catalysed transformations are less toxic, polluting and energy consuming than conventional human-designed methodologies (mainly those using valuable metals). Therefore it is not surprise that enzymes have served as a dominant source of inspiration in the pursuit of the “perfect” catalyst.

There are countless different approaches to the perfect catalyst, and there is no exclusive single “recipe” for success. 

Imatge

 

source: http://dugi-doc.udg.edu/bitstream/handle/10256/3655/qbis.pdf?sequence=1

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CATALYSIS AND ITS GREAT VALUE FOR SOCIETY

The production of petrochemicals derived from crude oil, the synthesis of small molecules that act as drugs and have specific functions in our body or the removal of waste and toxic products from the environment. These chemical transformations (and countless others), with a huge value for society, have a thing in common: They are catalysed.

The word “catalysis” may be familiar with you because it helps to produce cleaner car exhaust. This is actually true, but it just one application among many. What is, in fact, a catalyst? A catalyst makes a chemical reaction (such as the manufacture of a drug) happen, go faster, in a more selective way and usually with less waste. A catalyst is a molecule synthesized by humans (often made of metals) or it can be natural occurring (enzymes). In catalytic process, a very small amount of this foreign material increases the velocity of a chemical reaction without being consumed in the course of the transformation. Catalysis is at the heart of chemistry as it provides very powerful tools for converting basic chemicals (primer materials) into useful products for society in a sustainable manner.

Nowadays, catalysis is ubiquitous in many industrial areas: in the petrochemical industry, where catalysts play a crucial role in the “cracking” process (the breaking up of large hydrocarbon molecules into smaller and more useful units). This industry produces a wide range of consumer products, including gasoline, cosmetics, fertilizers, detergents, synthetic fabrics, asphalt or plastics. Catalysis permits the transformation of raw materials into these products in an easier, faster and “greener” fashion. Also in the pharmaceutical industry, where catalysis strongly helps, for instance, to reduce the number of steps involved in the synthesis of medications, thus increasing the efficiency of the process and promoting financial viability for the manufacturer. On the other hand, catalytic chemistry is used in many different ways to treat hazardous materials released to the environment. When toxic substances contact the suitable catalyst they can be filtered out or converted into more “eco-friendly” materials. This is the case of vehicle exhausts: A catalytic converter, consisting of an active metal, promotes the conversion of the pollutants from the internal combustion engines into less toxic substances (carbon dioxide, water and nitrogen).

However, the grand challenge for catalysis in the 21st century will be energy production. The high fossil fuel costs, the need to increase the use of biomasses, the introduction of the use of more environment-friendly energy vectors (such as hydrogen fuel cells), the development of new ideas to combine chemical and electrical energy production (more preferably using waste and residues as raw materials) or the extension of the use of solar energy will push to speed up the transition towards more effective renewable energy technologies. And catalysis is the core technology to achieve these objectives. Catalysis is an enabling factor for the transition to a new smart-energy world.

During the past years there has been growing interest in the improvement of catalysts in order to increase process efficiency, reduce energy and produce cleaner products. In the next post we will discuss on the different ways to fulfil this aim. Image

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