India's Most Advanced Nuclear Reactor Approaches Finish Line (NDTV)

[eppur_se_muova]

This development now marks the use of plutonium as a nuclear fuel and more importantly the first steps at using thorium as an atomic energy source.
Written by Pallava Bagla
Updated: July 30, 2024 5:32 pm IST

New Delhi:

India's atomic energy program has crossed a big hurdle, the country's most advanced and most complex nuclear reactor the Prototype Fast Breeder Reactor (PFBR) located at Kalpakkam in Tamil Nadu has finally got approval from India's atomic regulator to start loading the nuclear fuel and then to go ahead and initiate the controlled chain reaction. "It is a huge milestone for India's self-reliant atomic energy program," confirmed Dinesh Kumar Shukla, Chairman of the Atomic Energy Regulatory Board who added that the "PFBR is an inherently safe reactor".

This development now marks the use of plutonium as a nuclear fuel and more importantly the first steps at using thorium as an atomic energy source. India has limited reserves of uranium and all plutonium is anyways generated in atomic plants as natural plutonium does not exist, on the other hand, India has huge reserves of thorium and hence the country is mastering and developing complex technology to use thorium as fuel. Experts say if India can tap thorium as a fuel, the country can be assured of energy independence and find the potential 'akshay patra' for energy that will last for more than three centuries.

A fast breeder reactor is very unique and to a layperson these defy basic logic since breeder reactors produce more fuel than they consume and that is why some describe these reactors as an endless source of energy. The word 'fast' in these reactors comes from the use of high-energy fast neutrons. India has a functional Fast Breeder Test Reactor (FBTR) at Kalpakkam that has been functioning for the last 39 years.
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The Fast Breeder Reactor (FBR) will initially use the Uranium-Plutonium Mixed Oxide (MOX) fuel. The Uranium-238 "blanket" surrounding the fuel core will undergo nuclear transmutation to produce more fuel, thus earning the name 'Breeder'. The use of Throium-232, which in itself is not a fissile material, as a blanket is also envisaged in this stage. By transmutation, Thorium will create fissile Uranium-233 which will be used as fuel in the third stage. FBR is thus a stepping stone for the third stage of the program paving the way for the eventual full utilization of India's abundant thorium reserves.
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more: https://www.ndtv.com/science/prototype-fast-breeder-reactor-indias-most-advanced-nuclear-reactor-approaches-finish-line-6223347


NOTE: This is a mainstream press source so emphasizes politics, regulation, and a bit of boosterism over technological depth. Still interesting to see an update.

India apparently has a huge portion of the earth's thorium deposits, mostly as placer sand deposits produced by erosion of thorium-containing rocks.

Here's an interesting little tidbit from Wikipedia:

Thorium has been produced in excess of demand from the refining of rare-earth elements.[29]

https://en.wikipedia.org/wiki/Occurrence_of_thorium

[NNadir]

1. I very much support this fuel cycle proposal, and have long felt that heavy water reactors with mixed....

...thorium/uranium fuels represent a path forward to addressing the issues of depleted uranium valorization to generate the plutonium we will need to slow extreme global heating.

India has a fleet of heavy water reactors (of the CANDU type, of which they are knockoffs) and thus is well situated to exploit this option. The ²³³U that will be generated can be exported and mixed down with depleted uranium and eliminate the expensive and somewhat problematic enrichment systems.

The fast neutron cycle is, of course, a key to succeeding.

All this said, the Kalpakkam reactor is a straight up sodium cooled reactor; these reactors have been a mixed bag, with the scaled up Monju in Japan and the Superphenix in France having not succeeded commercially or in service. The BN-600 in Russia and the EBRII in the US did better. (The Oklo SMR is built around the EBRII technology.)

In discussions with my son I understand a problem that I hope has been considered with Kalpakkam; specifically materials science issues. One of the things that generates a lot of complaints by my son's Ph.D. advisor is that innovative materials are not considered in nominally "new" reactor types, and that people tend to do things the way they've always been done, because they've always been done that way. This is a very bad reason to do something, because it's always been done that way, particularly in light of systems that did not live up to expectations.

Personally, I feel that we need to move beyond sodium as a fast reactor coolant. Before I die, I want to be sure to leave ideas about better options in my son's head. There are many better options I think.

[eppur_se_muova]

2. "... do things the way they've always been done, because they've always been done that way"

All too prevalent, in so many spheres of human activity.

I remember once reading an ostensible aphorism of "tradition is a set of answers to which we have forgotten the questions", and my immediate reaction was, "do we know the questions are still relevant ?". I believe the context was traditional marriage and family customs, and probably being used to justify something like brideprices for virgins.

Sad to think that in a field built on so many scientifically determined principles, the path of least thought would still be in play.

[NNadir]

3. Well, we have to keep in mind that the worst nuclear reactor is still better than the best fossil fuel plant.

One has to navigate a number of issues in dealing with complex technology; one of those is the supply chain. It's probably cheaper and easier to do things the old way; more difficult to be innovative, since efforts at innovation can be costly simply because not everything works the first time.

There are some innovative approaches in the new era of nuclear creativity. For example, although I'm not really a FLIBE (BeF₂/LiF eutectic) kind of guy, Kairos has made an effort to bring this new supply chain issue forward for its high temperature reactors. For FLIBE it is probably still true that the optimal structural material is probably that developed in the 1960's, the nickel alloys Inconels and/or Hastelloys. (I say that without being, as my son is, a materials scientist.)

In my own thinking, I have tended not to pay much attention to sodium cooled fast breeders in any other than a general sense. I'm more of a "breed and burn" kind of guy, which work rather like a candle, as Sekimoto put it, although I would modify the concept by employing liquid metal fuels, low melting plutonium alloys, of which there are many of note. This would require, I admit, quite a bit of research, almost certainly costly research.