Fast-breeder reactors - a dying breed

By M. V. Ramana

Near the town of Kalkar in Germany, close to the border with Holland, a new amusement park is being built by a Dutch entrepreneur for about $ 3 crores. What is different about this park is that it was originally supposed to be Germany's first full-size, commercial fast-breeder reactor. After completing construction of the reactor and spending over $ 500 crores, in 1991 the German Government decided to abandon the project.

Germany is not alone in renouncing fast-breeders. The trend started with the United States - the first country to build a breeder reactor. In the late 1970s, even after devoting the bulk of energy research and development funding to breeders for two decades, it stopped the programme.

France and the UK, despite pursuing large breeder programmes for several decades, have no plans of constructing any more. Japan has not restarted the Monju reactor that was shut down after a sodium fire in December 1995. Among countries that have constructed breeders, Russia is isolated in supporting further development. But given its financial condition, the large amounts of money required are not forthcoming.

These setbacks for fast-breeder reactor programmes around the world have not deterred the Department of Atomic Energy (DAE). Recently, after two decades of painfully slow progress with a fast-breeder test reactor (FBTR), the DAE has proposed to build a 500 MW Prototype Fast-Breeder Reactor (PFBR), to be followed by many such reactors. The DAE argues that we need breeder reactors because India's uranium resources are limited. While the latter fact is true (at least given current uranium extraction technology), the conclusion drawn about the necessity for breeders is mistaken.

Mere availability of an energy resource cannot determine a country's energy strategy. If that were to be the case, then clearly we could derive the required power from solar photovoltaic cells, for example. The Ministry of Non-Conventional Energy Sources estimates that the potential for solar energy using photovoltaic cells is about 20 MW/sq. km. Thus, less than 5,000 sq. km. (less than one-six hundredth of India's total area) would suffice, utilising present and easily available technology, for producing India's current installed electricity capacity. But it would be extremely expensive and uneconomical at the present time.

Fast-breeder reactors have the same problem - they are expensive, largely due to important safety concerns. These reactors generate a large amount of heat in a very small volume and use molten metals to remove the heat. The PFBR will use liquid sodium. Since sodium is opaque and burns on contact with air or water, designing reactors and their maintenance to take these properties into account has made them costly to build and maintain. It also makes them susceptible to serious fires and long shutdowns - the French Superphenix reactor operated for less than one year during the first 10 years after it was commissioned.

Unlike small test reactors (such as the FBTR in Kalpakkam), large fast-breeder reactors often have what is called a positive sodium void co-efficient. What this means is that, if for some reason the sodium were to heat up and vapourise, then it would increase the reactivity of the core of the reactor. If the operating system failed to insert control rods fast enough, the increased reactivity would, in turn, heat up the sodium further; this chain could ultimately cause a fuel meltdown into a supercritical configuration and a small nuclear explosion.

Similarly, because the fuel is plutonium that is about 30,000 times more radioactive than uranium-235, safety precautions are required during fabrication of fuel. Just fabricating mixed oxide (MOX) fuel has proven to be several times as expensive as the total cost of uranium fuel used in heavy water reactors (such as the MAPS reactors in Kalpakkam). The costs of reprocessing and recovering plutonium run to millions of rupees per kg of plutonium. And the core needs 2000 kg of plutonium initially before becoming operational.

All these factors make breeder-generated electricity very expensive.

Costs apart, what role can breeders play in satisfying future electricity demands? A study by Mr. Rahul Tongia and Mr. V. S. Arunachalam (ex-scientific adviser to the Prime Minister) found that even under optimistic assumptions, it would be the middle of the next century before breeders using the oxide fuel proposed for the PFBR contribute even 20% of the total electricity generated at that time (Current Science, 25 September 1998). Even assuming the use of metallic fuel - not used by DAE so far - this would be reached only by the end of this century.

If it will take a century before these breeders come to play a non-negligible role, then one has to allow for highly probable advances in technology and consequently lower prices for renewable sources of energy, such as solar and wind power. Prudence demands greater investments in researching such technologies, which are safe and sustainable, and the institution of an active programme of energy efficiency improvements and demand side management.

Breeders started by being the reactors that would satisfy humanity's energy needs. The subsequent saga of breeder reactors has shown that hope to be impractical. Paraphrasing a saying from the electronic chip industry may best summarise the persistent belief among some nuclear engineers that breeders are the panacea for energy needs: Breeders are the reactors of the future, and always will be. It is time to learn from history and abandon that pursuit.

(The writer is a research associate at the Program on Science and Global Security, Princeton University, U.S.)

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