India’s Nuclear Dream Is Finally Coming True

[00:00:00]In the depths of space, long before the creation of the Earth, the merger of two neutron stars created energies a billion times higher than the light of every star in our galaxy put together. In this neutron-rich environment, elements absorb neutrons and before they could decay, >> [music] >> another and another until they took on somewhat stable forms expelled away from the merger event towards the interstellar nebula that would later coalesce into the Sun and planets [music] that make up the solar system that humans came to inhabit. Geological processes came to settle almost 16% of the thorium in India, mostly concentrated in the coastal monazite sands, but strangely, very little uranium made it to our shores. This quirk of fate meant that when our nuclear energy program was conceived, the creators had to think of a future in which the country would be able to supply its [music] own nuclear fuel. The problem was obvious and its solution simple in theory at least. Thorium is not fissile, but it has a potential to turn into something fissile. So, in stage one, we'd build pressurized heavy water reactors with natural uranium containing 0.72% uranium 235 as fuel and breed plutonium 239 from uranium 238. In stage two, we'd build fast breeder reactors where we would burn plutonium 239 and create uranium 233 from thorium alongside more plutonium 239 from uranium 238. And in stage three, the journey would be in its final stretch.

[00:01:31]Uranium 233 as fuel breeding more uranium 233 from thorium and energy independent nation. So, we've had stage one pressurized heavy water reactors for decades now. And just a few weeks ago, stage two finally began. On 6th April, the prototype fast breeder reactor at Kalpakkam finally achieved criticality.

[00:01:50]Not just a demonstration plant, but one that will put energy on the grid within a few years.

[00:01:57]Every nuclear reactor generates heat [music] and eventually boils water. It's how they generate and transfer this heat that makes each of them different. So, here's what sets the prototype fast breeder reactor >> [music] >> or the PFBR apart. The fuel is plutonium-uranium oxide. [music] The plutonium-239 used in this reactor was bred in stage one from uranium-238, which when bombarded with neutrons turns into plutonium-239. If you're not sure what beta decay is, let me tell you.

[00:02:26]It's basically the transformation of a neutron to a proton and an electron, which increases the atomic number by one, shunting the element right on the atomic table. So, hitting things with neutrons lets us turn one element into another. Plutonium-239 can sustain a controllable chain reaction only in the fast spectrum. So, we can't use water to transfer heat like we did in stage one pressurized heavy water reactors. Water slows down neutrons, pushing them into the thermal spectrum. Thermal spectrum neutrons are more readily absorbed by other elements like the uranium-238 itself. So, they don't allow plutonium-239 to sustain a controlled chain reaction. So, for stage two, scientists had to swap the water out for sodium. Now, you're probably thinking, "Sir, have they thought this through?

[00:03:10]Isn't sodium one of the most reactive elements in existence, reacting violently with both air and water, which are two of the most common things around?" And if you're thinking that, you're absolutely right. [music] Spot on. Right on the money. In fact, issues with sodium coolants have always plagued this class of reactor. Superphenix in France and the Monju reactor in Japan both ran into issues with sodium leakage. But fortunately, due to our somewhat belated arrival to this stage, we've had the opportunity to study those failures and put in preventative measures to keep the same fate that befell those reactors from happening to us. Though, especially in the case of Superphenix, that was definitely not why it failed. The molten sodium in the PFBR is inside the reactor vessel or another way to imagine it is that the reactor core containing fuel rods and control rods is submerged [music] within liquid sodium. The primary coolant pumps drive the sodium from the cold pool through the reactor. This heats them up and then the pressure from the pumps pushes the sodium from the hot pool through four heat exchangers [music] which further transfers this heat from reactor core to the secondary sodium loops. They're basically playing hot potato with the reactor core's heat.

[00:04:20]>> You take it. No, I you take it. No, I it's too hot. I need water.

[00:04:24]>> Yeah, I can take this. No problem.

[00:04:26]Ah!

[00:04:28]>> So yeah, the water dies in the end. It's ghost. Steam runs a turbine and that's how we get electricity. That's the technical explanation. All right, so I think you kind of know how this reactor works now. Core hot, submerged in sodium, pump circulates the sodium, sodium gets hot, transfers to non-radioactive sodium, then steam.

[00:04:45]Clear so far? But where is the breeding?

[00:04:47]This just seems like a regular reactor with sodium instead of water to make things more exciting, [music] I guess. Well, this thing we showed earlier, it's not just for design. This is a blanket radially arranged around the reactor core. This absorbs a fast spectrum neutron to turn into uranium 239 for about 24 minutes, then decaying into neptunium 239 >> [music] >> which decays again after 56 hours into plutonium 239, a long-lived isotope with a half-life of 24,000 years which we can then reprocess and use as stage two's primary fuel. The fuel makes fuel. So why do we even need the [music] stage three again? I mean, we've kind of got the self-sustaining process going.

[00:05:29]Unfortunately, as we discussed at the start of the video, India is rich in thorium but poor in uranium. We depend on other countries for it like Russia, Kazakhstan, and Australia and maybe soon Canada. So in stage three, we will put thorium into a blanket >> [music] >> and just like uranium 238, it will absorb a neutron and then undergo successive [music] beta decays to turn into uranium 233, which has a half-life of 150,000 years. With uranium 233 as a primary fuel, we can keep breeding more of it using thorium. On stage three's completion, these reactors will be able to account for all of India's electricity requirements for 900 to 3,000 years, I guess, depending on whether you're the kind of person who leaves the light on or off when you enter the house. There's a long way to go, but the much-delayed second phase is finally underway. And once low-power testing is completed, this reactor will be followed by two more in the same power plant. These are not small reactors. 500 MW electric means it can power around 200,000 homes. And why you see so much excitement globally around this is because this is the only way we can produce clean, firm, stable base-load electricity in the here and now. From far-away galaxies, massive packets of energy race through the universe to land in our backyard. And ever since we found out, generations of scientists have been dreaming of cracking them open to get at the energy within. Gifts from the cosmos that we must now learn to unseal at a planetary scale. Uranium was somewhat easy.

[00:07:04]Thorium has been a tougher nut to crack aside from small experimental setups.

[00:07:09]And do note that they have not actually done it yet. But given what they've already accomplished, it is not too far to extrapolate that this is the dawn of the coming of the thorium age. I hope you guys enjoyed this video. We will be back soon with more, for real this time.

[00:07:26]Bye.