Long-term fix vital for nuclear waste

Michael Richardson, For The Straits Times 25 Jan 10;

THE Pacific Sandpiper, a specially built cargo ship with safety features far in excess of those found on conventional vessels, left Britain's Barrow port bound for Japan last week.

The security surrounding its departure indicates that something out of the ordinary is aboard. The Pacific Sandpiper and several sister ships make no port calls on their voyages between Europe and Japan because they carry potentially lethal nuclear material.

In the Sandpiper's hold on this journey to Japan via the Panama Canal is only one item of cargo - a giant cylinder weighing more than 100 tonnes. Inside are 28 stainless steel containers, each nearly one-third of a metre thick. They are packed with 14 tonnes of highly radioactive waste that has been turned into solid glass form to make it safer and easier to handle.

It is the first of a series of such shipments planned for the next few years to Japan from Britain's Sellafield nuclear storage and reprocessing complex. Three years ago, a dozen similar shipments from France to Japan were completed.

Used fuel from nuclear power reactors that generate about one-third of Japan's electricity has been shipped to Europe for reprocessing since 1969, while vitrified waste has been sent back to Japan since 1995. There have been over 170 of these ocean shipments without any incident involving the release of radioactivity.

But the elaborate and costly arrangement casts light on two of the most problematic aspects of civilian nuclear power: how to prevent the spread of nuclear weapons material and know-how to terrorists and rogue states, and how to store nuclear waste safely for the long term.

With the number of power reactors expected to rise from today's 435 in 31 countries to nearly 570 in 42 countries by 2020, and with much of this expansion expected to take place in Asia and the Middle East, the need for safeguards on material that could be used to make nuclear weapons is obvious.

Recycling fuel from nuclear reactors under strict national and international regulations is one method being developed. When uranium oxide fuel has been used in a reactor for three or four years, it becomes less efficient and is replaced with fresh fuel.

The spent fuel can then be chemically treated to recover usable uranium, associated plutonium and radioactive waste, a system known as reprocessing. Although expensive, this cycle provides up to 25 per cent more energy from the original uranium. It also reduces the volume of high-level waste to about one-fifth of what it would otherwise be.

Eventually, advances in reprocessing and a new generation of fast reactors may be able to recover and reburn even more of the fissile and radioactive material from used fuel, further reducing waste and reducing the proliferation risk.

So far, about 90,000 tonnes of used fuel from commercial power reactors have been reprocessed, mainly in Britain, France and Russia. By 2030, another 400,000 tonnes of used fuel are likely to pile up, an average of 20,000 tonnes a year. At present, annual global reprocessing capacity is about 3,800 tonnes per year for normal uranium oxide fuel, and about 1,700 tonnes for other nuclear fuels, according to the World Nuclear Association.

Much of the spent fuel piled up by 2030 will be in Asia. Japan, India, China and South Korea aim to emulate the main reprocessing centres in Europe and Russia. They see the technology as the key to a lucrative nuclear service industry as well as being one that is vital to their own energy security.

Meanwhile, power reactors in most countries have been built without safe long-term underground storage arrangements being put in place, mainly because of the high cost involved and public resistance at potential sites.

In the United States, which generates 20 per cent of its electricity from nuclear power, opponents of a plan for a national repository beneath Yucca Mountain in Nevada have stymied it for years.

A recent analysis by the US Government Accountability Office said it could cost US$67 billion (S$94 billion) to build the Yucca facility and operate it for 150 years.

High-level radioactive waste is accumulating at a rate of about 12,000 tonnes per year worldwide. When used fuel is removed from a reactor, it must cool for up to 50 years under water or in dry storage, where circulating air gradually removes the heat.

The level of both radioactivity and heat from spent fuel, or from the dangerous waste material extracted from the fuel during reprocessing, falls rapidly in these years down to about one-thousandth of the level when the fuel was removed from the reactor.

During this period, storage may be at one central place, as in Britain's Sellafield complex, or at the reactor site where the spent fuel was removed, as in the US. But either way, the time for permanent storage of the most toxic waste deep underground in geologically stable rock, salt or clay in countries that have been generating electricity from nuclear power for decades is fast approaching.

Without a long-term solution, the pile of radioactive 'rubbish' will become so big and so widely dispersed that it may be impossible to manage safely.

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