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Combating Climate Change with Nuclear Energy

Dr Victor Luca

The International Energy Agency and other institutions make available databases covering all aspects of energy generation and consumption. Each year they publish a volume entitled Global Energy Outlook in which they make projections.

Figure 1. Total global electricity consumption projected out to 2030 and compared with total renewable energy generation.

Figure 1 has been created from IEA data and shows the global energy consumption in TWh projected out to 2030 (blue). On the graph is also plotted in green is the renewable energy (hydro and non-hydro) generation in TWh. It can be seen that the two lines are diverging. In other words if present trends continue, the two lines will never meet. That is, we are consuming significantly more energy on an annual basis than is being added from all renewables. Today most of the electricity contributing to the blue line (60%) is produced by burning fossil fuels. Until the two lines in the graph intersect it is clear that we are not going to decarbonize electrical energy production. For this to happen we would essentially need to replace all annual 29,000 TWh required by 2030 by renewables. Yet today, renewables, which includes hydro, only accounts for about 8,200 TWh of generation. So we are far short of where we need to be. Today non-hydro renewables account for only 10.8% of total electricity generation almost on par with nuclear energy.

Plagued by concerns of safety and costs the development of nuclear power plants peaked in 1976 and then decreased steeply. Thus we turned our backs on a power source that offers low emissions base-load electricity and a potentially important tool for the decarbonization of the planet. I believe that we now need to look a bit more objectively at this power source.

It is first worth briefly considering the impressive history of nuclear development. The first controlled thermonuclear reaction in which uranium atoms were ‘split’ (fission) was conducted at the University of Chicago by the Italian-American Enrico Fermi and his team on 2-Dec-1942. Within about 30 years the world had 216 large operational nuclear fission power reactors producing electricity. By the year 2000 that number had swelled to over 440 and nuclear plants which were producing about 17% of the world’s total electrical energy production. Peak reactor construction occurred during the mid-70s. In the two years 1975 and 1976 seventy reactors were connected to electrical power grids.

All of the fission reactors built to date have operated on an open fuel cycle meaning that the fuel is used only once. In principle, when spent fuel is discharged from a reactor the fuel still contains 95% of the energy content of the original fresh fuel and so the prospects for utilizing the remaining energy content is enormous. Development of processes for nuclear fuel recycle are well advanced. In fact partial recycling is already undertaken in many countries.

That the power of the atom could have been so quickly harnessed to produce such an enormous amount of energy represents nothing less than a scientific and technological miracle.

One of the most important aspects of nuclear fission energy is the energy density that can be achieved.

Figure 2 shows that to produce the same amount of wind and solar energy as can be produced from the 430 acres (1.7 km2) occupied by the Hinkley Point nuclear power plant would require 580x the amount of land for wind and 302x the amount of land for solar. The small footprint of nuclear energy relative to renewables such as wind and solar is the minimal requirement for land which could otherwise be used to grow food.

The Flamanville nuclear power plant in the Manche region of France occupies a mere square kilometer of land and will produce 4.25 GW of electrical power once the third Generation III+ EPR reactor is brought on line. This represents almost the total of New Zealand’s annual electricity needs. At its peak, nuclear energy accounted for up to 85% of France’s total electricity generation. France also became Europe’s largest energy exporter. The reason that France pushed nuclear energy so hard from the beginning was that it is a country lacking in other energy resources. It was a question of energy security. As a consequence of its use of nuclear energy France’s per capita GHG emissions are a fraction of New Zealand’s which ranks 16th in the world.

Traditional nuclear power reactors have capacity factors that exceed 90% meaning that they operate almost continuously producing the same amount of electricity regardless of the time-of-day and weather conditions. They are only really ever shut down very briefly for refueling and occasional inspection and maintenance. A typical current generation nuclear reactor has an operational lifetime of around 60 years.

Importantly, during operation, a nuclear plant emits negligible greenhouse gases or radiation. In fact radiation levels around a large operating nuclear plant are lower than those of a coal-fired power station.

Excluding events such Chernobyl and Fukushima, nuclear energy has an impeccable safety record that is comparable to that of solar and wind energy. Nuclear energy is in fact 350x safer than coal energy when measured in terms of annual deaths.

Of the two most significant nuclear safety events, Chernobyl cannot really be called an accident at all. It was the result of an inherently unstable reactor design with known flaws being pushed deliberately beyond its limits during testing. It has been suggested that the real culprit at the heart of the accident was the Soviet system itself that rewarded performance and indirectly and tacitly encouraged risk taking. I guess many of us have seen the HBO movie by now.

Fukushima was the result of a Tsunami caused by an earth quake that directly took more than 15,894 lives, injured 6,152, and displaced 228,863 and resulted in the disappearance of another 2,562. Not a single person was killed during the hydrogen explosions that destroyed the Fukushima nuclear plant. The plant itself was built near the sea and was protected by a sea wall that proved to be inadequate.

New generations of reactor designs will be impossible to melt down as they will have passive safety features. For instance, the pebble bed reactor design that has been around for decades will be fueled by tennis ball-sized spheres of graphite containing uranium. As the reactor heats up beyond a certain level the nuclear chain reaction slows and then stops. Physics simply doesn’t allow a melt-down.

Many people object to the nuclear waste produced by nuclear energy. This is a complex issue in which I have worked for more than two decades and I can assure folk that technical solutions do exist. For spent nuclear fuel, deep underground repositories (500 - 600m) in appropriate geological formations and employing multi-barrier containment systems, very deep bore-holes (4 - 5 km) and closure of the fuel cycle through recycling are all concepts that are well advanced. Long-term interim storage in above surface canisters is also well proven technology.

I always find it bemusing that we humans are paranoid about nuclear energy production that has an impressive safety record but are OK with coal burning with its shockingly bad safety record. Think Pike River mine.

At the same time we seem to be oblivious of the waste produced by coal-fired (or gas-fired) power plants. Aside from the soot, and fly ash (PM2.5) the emission of copious amounts of green-house gases is threatening organized human life on this planet. And make no mistake about it folks, the evidence couldn’t be clearer.

In fact, the major impediments to a large scale nuclear build out are not the potential for accidents, or the waste that is generated, it is the cost and time involved in licensing traditional large reactor designs and the final build costs. For example the Hinkley Point power plant consisting of two French-design EPR reactors will cost north of $22B by the time it is completed in 2026 and have a power output of 3.2 GW. This amount of electricity is enough to power close to one million homes.

These costs of nuclear reactor construction could be greatly reduced by streamlining the licensing process and through design standardization. This is how France built so many nuclear reactors in such a short time.

Other options for reducing costs are to scale down the reactor size so that all components can be built in a factory and simply shipped to site. This is what is behind initiatives to mass produce so-called Small Modular Reactors. For instance, Rolls-Royce SMR Limited has submitted its 470 MWe small modular reactor (SMR) design for entry to the UK's Generic Design Assessment (GDA) regulatory process. A Rolls-Royce-led UK SMR consortium aims to build 16 SMRs.

Patrick Moore, a co-founder of Greenpeace, now co-chairs a pro-nuclear power coalition. He has stated publicly that “my views have changed because nuclear energy is the only non-greenhouse-gas-emitting power source that can effectively replace fossil fuels while satisfying the world’s increasing demand for energy”. Other luminaries including James Hansen, Bill Gates, Jeff Bezos and many others are now backing nuclear power.

When in 2010 Time Magazine asked Stephen Hawking which scientific discovery or advance he would like to see in his lifetime, he replied without hesitation: "I would like nuclear fusion to become a practical power source. It would provide an inexhaustible supply of energy, without pollution or global warming." That is all very well but we are unlikely to even have a working prototype that produces more electrical energy than it consumes before 2030. Even the $20B ITER project will not produce any relevant amount of energy.

However, right now we have at our disposal mature and proven nuclear fission technology that in principle could be deployed at massive scale to help solve our energy and climate problems. What are we waiting for?

Author: I have been conducting materials chemistry research on various aspects of the nuclear fuel cycle within various governmental nuclear agencies for more than 20 years and the history of nuclear energy never ceases to amaze me. I have also conducted research on lithium ion batteries and the photoelectrocatalytic generation of hydrogen.

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