If the landmark agreement on civilian nuclear cooperation between the United States and India has hit a roadblock, it is over India's fast breeder reactor programme.
It is an issue that India's nuclear scientists agree on unanimously.
They want the Manmohan Singh government to rebuff the US demand to place the country's fast breeder reactor programme under a civilian plan and open it up to International Atomic Energy Agency safeguards.
Here is what three top nuclear scientists have to say:
Anil Kakodkar, Chairman, Atomic Energy Commission: 'Putting the fast breeder reactor programme under IAEA safeguards will jeopardise India's strategic interests. The programme just cannot be put on the civilian list. This would amount to getting shackled.'
P K Iyengar, former chairman, AEC: 'Why is this government going back on its word? We are a nuclear weapon country and it is for us to decide (which reactors to put under IAEA safeguards).'
A N Prasad, former director, Bhabha Atomic Research Centre: 'As a (nuclear) weapon State, and a non-signatory to the NPT (nuclear Non Proliferation Treaty), India should be able to decide as to what we want to emphasise as our priorities; and a collective wisdom will help the government also.'
Washington insists that if the nuclear deal is to be clinched, the fast breeder test reactor and prototype fast breeder reactor at Kalpakkam near Chennai have to be thrown open to IAEA surveillance.
If you are wondering what the fuss is about, read on:
What is the fast breeder reactor programme?
The fast breeder reactor marks the second stage of the nuclear power programme in India. Unlike a thermal nuclear reactor, a breeder reactor generates more fissile plutonium than it consumes in the process of generating energy.
According to Dr A Gopalakrishnan, former chairman, Atomic Energy Regulatory Board, India has eight fast breeder reactors under construction now at Kalpakkam. By 2020 India will utilise thorium in these breeders as fissile material, which will enable the country to produce 1,55,502 GW energy per year.
The programme will help meet India's exploding energy needs.
How is the Kalpakkam station connected with the programme?
The Madras Atomic Power Station in Kalpakkam is the base for India's fast breeder reactor programme.
The centre built a small fast breeder test reactor in 1985.
In 1997, the Indira Gandhi Centre for Atomic Research, the research and development establishment of the Department of Atomic Energy at Kalpakkam, then successfully built a 40-megawatt sodium-cooled fast breeder test reactor in 1997.
In 2002, the Indian government announced the construction of the country's first 500 MW prototype fast breeder reactor.
What is the status of the project, now that it is under a cloud?
It is on full throttle. With a budget of Rs 3,492 crore (Rs 34.92 billion, approximately $0.7 billion), the project is a proof of India's capability to work on cutting edge nuclear technologies with very little foreign assistance.
How and why it is linked to the India-US nuclear deal?
The fast breeder reactor programme, apart from being a way to meet India's leapfrogging energy needs, is also a vital part of India's nuclear weapons programme -- it produces weapons-grade plutonium.
That is why the US wants it under the IAEA scanner.
Is it true that India is aiming at fast breeder reactors when the rest of the world is abandoning the technology?
Yes. And there is a reason for that. The Department of Atomic Energy in India sees fast breeder reactors as the technology that can secure the country's energy future because it can convert thorium nuclear fuel.
India is one of the few countries that use thorium as an alternative fuel for nuclear reactors. The reason is that India has been compelled to look beyond thermal nuclear reactors because of the scarcity of natural uranium in the country. Thorium is a nuclear fuel India is rich in.
Why have other countries lost interest in the fast breeder programme?
The fast breeder reactor was once considered the best energy source to meet growing electricity demands and to help conserve uranium resources.
Most developed nations have now abandoned the technology.
Experts say, first, fast breeder reactors are not cost competitive with thermal nuclear reactors.
Second, cheaper alternative energy sources are available across the world.
Third, accidents caused by liquid sodium leakage at the Monju reactor in Japan and the Superphenix in France forced countries like the US to turn down fast breeder reactor technology.
Fourth, there is a growing fear that weapons-grade plutonium could fall into wrong hands - read terrorists The global trend is towards smaller, reactors that are environment-friendly and proliferation-proof.
The US says Japan has opened its Joyo experimental breeder reactor and Monju prototype reactor to IAEA safeguards.
The Japanese fast breeder reactors are subject to full-time advanced verification systems such as neutron coincidence counters, radiation monitoring systems and fuel flow monitors, in addition to video surveillance by the IAEA.
The US wants similar safeguards for the Kalpakkam reactors.
What is India's argument?
India says the US cannot compare the Indian and Japanese fast breeder reactor programmes.
First, it says Japan's Atomic Energy Agency has the freedom to source components and nuclear technology from any part of the world. But the Department of Atomic Energy in India has to rely on its own resources and technologies for its nuclear programmes.
Second, India fears that putting its fast breeder reactor programme open to IAEA inspection will seriously compromise the quality and scope of ongoing nuclear research in India.
Third, India says there can be tremendous leakage of intellectual property we have indigenously developed -- as our reactors would be open to IAEA inspection.