Hidden from public, on the shores of the Bay of Bengal at Kalpakkam near Chennai, Indian nuclear scientists are in the final throes of starting a high-tech giant stove more than 15 years in the making.

This novel nuclear reactor is a kind of an 'akshaya patra', the mythical goblet with a never-ending supply of food.

The Department of Atomic Energy is getting ready to commission its ultra-modern indigenously designed and locally mastered fast breeder reactor.

Experts say to make nuclear energy sustainable, one sure shot way is to make fast breeder reactors mainstream.

Yukiya Amano, Director General of International Atomic Energy Agency (IAEA), Vienna, says "fast reactors can help extract up to 70 per cent more energy than traditional reactors and are safer than traditional reactors while reducing long lived radioactive waste by several fold." 

Easier said than done, since these reactors are also notoriously unstable and hence difficult to run reliably over long periods.

Called a 'Fast Breeder Reactor', these are a special kind of nuclear reactors that generate more atomic fuel than they consume as they work.

India has been running an experimental facility called a Fast Breeder Test Reactor (FBTR) now for 27 years.

This is a small nuclear reactor a forerunner for the monster that India has constructed at Kalpakkam called the Prototype Fast Breeder Reactor (PFBR). This will generate electricity commercially using the fast breeder route.

The world's only commercially operating fast breeder reactor is situated in the Ural Mountains of Russia at the Beloyarsk Nuclear Power Plant, not far from Russia's fourth largest city Yekateringburg.

The Russians today are the global leaders in fast breeder reactors having operated a fast breeder reactor called BN 600 since 1980.

In 2016, the Russian nuclear agency Rosatom commercially commissioned its big brother — the BN 800 fast breeder reactor.

This reactor produces about 800 MW of electricity and supplies it to the Ural region including the city of Yekateringburg.

While electricity that is produced is no different than any other electricity but the global community of atomic boffins is suitably chuffed about this unique achievement.

M Chudakov, now with the IAEA and well-known Russian fast breeder expert, calls "these reactors a bridge to the future as they can supply an almost unlimited supply of electricity".

All eyes are now on southern India where another global nuclear milestone is likely to be crossed this year.

Arun Kumar Bhaduri, Director of the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam says, "fast breeder reactors are far safer than the current generation of nuclear plants and that all efforts are being made to kickstart within this year India's first commercial fast breeder reactor at Kalpakkam." 

Such is the interest in fast breeder reactors that more than 700 of the best atomic scientists from over 30 countries gathered at Yekateringburg in IAEA's conference on the 'next generation nuclear systems for sustainable development'. The scientists deliberated on how to make nuclear energy last for several centuries.

Given India's expertise, the co-chair of the conference was Suresh Chetal, one of the early pioneers of fast breeder reactors who helped tame fast breeder reactors for New Delhi when he was at the IGCAR.

Many countries have dabbled with fast breeder reactors and have given up, first off the block was the US but it gave up since inherently American governments have an allergic response with re-processing of nuclear waste in addition since USA has enough supplies of fissile material there is no hunger to maximally extract energy from uranium.

Japan and France both had robust programs with fast breeder technology but repeated failure to safely handle liquid sodium forced them to more or less give up on fast reactors.

China is more than a decade behind India in trying to master this complex beast.

Russia invested heavily in developing the fast breeder technology but since it commissioned its first fast breeder reactor BN 600 in 1980 it suffered an economic meltdown as the former Soviet Union broke up and only recently Russia could gather enough resources to complete its upgraded fast breeder reactor BN 800.

Today the BN 800 is a flagship reactor that uses both uranium and plutonium as fuel and generates electricity that is supplied to the grid. A visit to the facility reveals a squeaky clean reactor where seasoned operators like Ivan Sidrow are also experimenters as they go about trying to design a bigger 1200 MW fast breeder reactor.

India's own PFBR is unique and rather different from the Russian fast breeder reactor though both use the same basic principle of physics.

Fast breeder reactors are called such not because they run faster but because the neutrons that sustain the atomic chain reaction travel at a much higher velocity than neutrons that help run the traditional atomic plants.

These are called breeders as they generate more fuel than they consume a fact hard to fathom since they seem to defy the laws of conservation of energy.

But a very unique quirk of elemental uranium makes this possible.

Nuclear reactors use a flavour of uranium called U-235 which unfortunately constitutes a minuscule quantity even in super purified uranium.

The larger component is what is called U-238 this flavour is the bulk but is essentially a waste product as the atomic reaction cannot be sustained by this elemental flavour.

In a fast breeder reactor the very special fast neutrons interact with the so called wasted uranium U-238 and converts it into a valuable resource. This is why fast breeders are akin to an 'akshaya patra'.

India's fast breeder reactor is even more unique as within it the country also deploys special rods of thorium which when they get exposed to or irradiated by fast neutrons they generate U-233 and a normally benign thorium turns into a valuable atomic material.

It is well known that India is very energy hungry and as economic growth takes place mega quantities of electricity will be required.

Unfortunately, nature has not been bountiful on India as the Indian land mass is not endowed with enough uranium but on the other hand the country has the world's second largest store of thorium.

Today the country in a well thought out strategy is mastering fast breeder reactors that can be an effective via media for utilising the vast thorium reserves.