Small nuclear reactors a new green option

Michael Richardson, For The Straits Times 17 May 10;

Nearly 440 big reactors in 30 countries generate 14 per cent of the world's electricity. There are at least 15 small reactors at an advanced stage of development in various countries which could help cut global emissions. -- PHOTO: AGENCE FRANCE-PRESSE

SENIOR Minister Goh Chok Tong recently outlined Singapore's plans for reaching eventual self-sufficiency in water supply for homes and industry.

Opening Sembcorp Industries' Newater plant, the fifth and largest so far, he said that reused water now met 30 per cent of total demand here and that this would rise to 40 per cent by 2020.

Beyond recycling, desalination promises unlimited supplies of fresh water for countries like Singapore, which can draw freely on water from the sea. The big drawback of desalination at present is the high cost of the energy-intensive process involved.

Nuclear power may offer a way forward, providing not just reliable and affordable electricity to the national grid, but also low-cost power for desalination, heat for a wide variety of industrial processes, and hydrogen fuel for urban transport - in other words, a package solution for Singapore.

Imagine a world in which many mid- sized cities and towns had their own small nuclear reactors to generate electricity and heat. By replacing plants using fossil fuel coal, natural gas or oil, these atomic generators - emitting almost no carbon dioxide, the main greenhouse gas from human activity - would make the world a more sustainable place. If done in time and on a sufficiently wide scale, this could help to avert a global climate change crisis.

The science and applied knowledge to do this are advancing fast. The International Atomic Energy Agency has estimated that global demand for small reactors could reach 500 to 1,000 units by 2040 as more urban centres, industries and remote communities seek low-carbon power not just for baseload electricity but also for low-cost heat to desalinate seawater, run energy-intensive mines and industries, and produce biomass-based ethanol and hydrogen - a zero-pollution transport fuel of the future.

Today, nearly 440 big reactors in 30 countries generate 14 per cent of the world's electricity. The spread of nuclear technology through small reactors would create new regulatory and proliferation challenges, but also help cut global warming emissions as the small reactors replace plants relying on fossil fuel.

There are at least 15 different small reactors, ranging from around 30MW to 300MW, in an advanced stage of development in Japan, the United States, Russia, China, South Korea, South Africa and Argentina. They are backed by many of the world's leading reactor designers and engineering companies.

The US Nuclear Regulatory Commission is preparing to start the process of approving the first of seven small reactor designs from October this year, beginning with Toshiba Corporation's Super-Safe, Small and Simple (4S) reactor - a 'nuclear battery' system, which will be offered in 10MW and 50MW versions.

The town of Galena in Alaska has given preliminary approval for Toshiba to install a 10MW 4S reactor, which the makers say will be able to operate continuously for 30 years without refuelling, something that normally takes place every few years with current large power reactors. After 30 years, the radioactive 4S fuel would be allowed to cool for a year. Then it would be removed for above-ground storage or underground disposal.

The whole 4S unit would be factory-built, transported to site and installed below ground level. Cooled by liquid metal sodium, it drives a high temperature steam cycle. Both the 10MW and 50MW versions are designed to produce heat at a constant 550deg C, suitable for power generation with electrolytic hydrogen production.

Hydrogen gas - whether burned in vehicle engines or used in fuel cells to generate electricity to drive vehicles - emits only water vapour in the exhaust.

However, hydrogen does not occur naturally. It has to be produced, mainly from natural gas. While inexpensive, this technique adds huge volumes of carbon emissions to the atmosphere.

Hydrogen can also be made by electrolysis, using electricity to split molecules of water into molecules of hydrogen and oxygen. This can be a low-carbon method if the electricity is generated from nuclear power or renewable energy sources, such as solar or wind.

However, it requires a water-splitting catalyst. Natural ones are enzymes used by plants during photosynthesis, but they are highly unstable. Commercially available metal catalysts, the best of which is the precious metal platinum, are stable but expensive. Platinum costs around US$2,000 (S$2,760) an ounce.

In what appears to be a major breakthrough, a team of scientists in the US recently announced they had discovered a metal catalyst about 70 times cheaper than platinum that could be used to split water molecules and produce hydrogen without organic additives and in different kinds of water, including sea water - the most abundant source of hydrogen on Earth.

Toshiba plans a worldwide marketing programme to sell 4S units. Eventually, it expects sales for hydrogen production to outnumber those for power supply as global demand for hydrogen for industry and as a pollution-free transport fuel rises rapidly.

Meanwhile, the US Energy Department announced in March that it was awarding US$40 million to two international groups to finish their conceptual designs and plans for next-generation reactors by August.

Both groups are proposing to build small reactors cooled by helium gas, which reaches temperatures of about 850deg C. The heat can be used not just to drive steam turbines to generate electricity but also for industrial and district heating.

Industrial applications include refining petrochemicals, plastic refining and hydrogen production - all areas of economic interest for Singapore.

The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies in Singapore.

Why it's not a solution
Straits Times Forum 24 May 10;

IN LAST Monday's commentary ('Small nuclear reactors a new green option') by Mr Michael Richardson, the small nuclear reactor technology was enthusiastically described as 'a packaged solution for Singapore' because not only will it provide the necessary energy for Singapore's future, but it will also reduce our dependence on fossil fuels.

Though I share the concern for the need to find an alternative energy source, I do not, however, share his enthusiasm for the small nuclear reactor technology.

# First, Mr Richardson emphasises that nuclear power can provide 'affordable electricity' for Singapore. However, historically, the promise that nuclear energy would be 'too cheap to meter' never materialised. This is because billions of dollars are needed to build a standard nuclear power plant, and much more to maintain and, later, decommission it.

Even though the small nuclear reactor is much cheaper - costing hundreds of millions instead of billions - it nonetheless produces electrical power only in the low megawatts range, rather than the gigawatts range a standard nuclear reactor produces. It is, therefore, unclear if electricity produced by the small nuclear reactor can ever be truly affordable.

# Second, if we pursue such small nuclear reactor technology, we are merely exchanging our reliance on fossil fuels for a reliance on uranium.

Mr Richardson asks us to imagine a pollution-free world filled with such small nuclear reactors. This vision is attractive but incomplete: for this will also be a world filled with new contests and strife to secure uranium, which by any estimate exists in far smaller quantities compared to the reserves of fossil fuels.

# Finally, the question remains on what Singapore ought to do with the radioactive spent nuclear fuels from such a small nuclear reactor. Although the option of reprocessing them exists, this will add new costs and will require nuclear expertise and containment facilities that we do not have now. Reprocessing inadvertently also produces plutonium, which can lead to unwanted nuclear proliferation.

From a citizen's perspective, do we want to burden the future generations of Singapore with such nuclear waste?

We have to be extremely cautious of this new technology even when it seems to promise us a source of green energy.

Jeffrey Chan

Advantages of small nuclear reactors
Straits Times Forum 29 May 10;

I WISH to offer a different perspective from Mr Jeffrey Chan ("Small nuclear reactor: Why it's not a solution", Monday).

The attractions of "third generation plus" small nuclear reactor technology are manifold. The reactor is the size of a bus and can be built in a factory, then shipped to a power plant where it can generate up to one-quarter the power of a large nuclear reactor but costs only one-tenth as much.

The other advantages are the reactor's compact modular design and much smaller containment vessel. A large storage area for fuel is also no longer required.

It will indeed be a wise decision for Singapore to adopt small nuclear reactors to help meet our ever-increasing electricity needs.

First, we do not have to work towards being completely free from reliance on fossil fuels. Instead our additional small nuclear reactors would balance the consumption of fossil fuels.

Nuclear power plants should be viewed as a means to mitigate the rampant consumption of fossil fuels, so as to reduce pollution. Such plants are not meant to completely replace fossil fuels. Looking to the future, uranium is a good counterbalance to fossil fuel.

Second, it is a myth that nuclear energy is "too cheap to meter". Nonetheless, it is a fact that the cost of electricity generated by nuclear energy is a fraction of that generated by burning fossil fuels.

Storage and reprocessing of spent fuel rods have become safer and more economical. Decommissioning of a nuclear plant after 30 to 40 years of service is part and parcel of the process. The benefits of cheaper and cleaner energy outweigh the justifications for more fossil fuel plants.

Third, large nuclear power plants do not necessarily suit nations with small land mass and high population density. Singapore is better off using uranium as an additional source. We should not be unduly worried about nuclear proliferation with a few small nuclear power plants here.

Come 2030, future generations would be thankful to our present leaders for their foresight in adopting small nuclear power plants to meet our electricity needs.

Paul Chan