India’s Three Stage Nuclear Power Programme

This programme was formulated in 1950s by Dr. Homi Bhabha to secure the country’s long term energy independence, via use of uranium and thorium reserves found in the monazite sands of coastal regions of South India. The ultimate focus is on Thorium Fuel Cycle. The three stages are as follows:

1. Pressurized heavy water reactor (PHWR)
2. Fast breeder reactor (FBR)
3. Advanced Heavy Water Reactor(AHWR)

Logics behind Stage 1 PHWR

• The first stage involved using natural uranium to fuel PHWR to produce electricity and producing Plutonium-239 as a byproduct. We note here that the PHWRs were chosen for the first stage because in 1960s, India had the efficient reactor design in terms of uranium utilisation. It was calculated that rather than going for creation of Uranium Enrichment Facilities, it would be wiser to create heavy water production facilities
• Moreover, using Pressurized Heavy Water Reactors rather than Light Water Reactors was also a correct and wise decision. While Pressurized Heavy Water Reactors used unenriched uranium, Light Water Reactors required enriched uranium. Further, India could domestically produce the components of PWHR, as opposed to LWRs. Furthermore the byproduct plutonium-293 would be used in the second stage.

Logic behind Stage 2: FBR

• The second stage involves using plutonium-239 to produce mixed-oxide fuel, which would be used in Fast Breeder Reactors. Plutonium 293 undergoes fission to produce energy, and metal oxide is reacted with enriched uranium reacts with mixed-oxide fuel to produce more plutonium-239.
• Furthermore once a sufficient amount of plutonium-239 is built up, thorium will be used in the reactor, to produce Uranium-233. This uranium is crucial for the third stage.

Logic behind Stage 3: AHWR

• The main purpose of stage-3 is to achieve a sustainable nuclear fuel cycle. The advance nuclear system would be used a combination of Uranium-233 and Thorium. Thus India’s vast thorium would be exploited, using a thermal breeder reactor.
• Thorium use was reserved for the last stage because despite having significant availability, use of Thorium in production of energy has been full of certain challenges. It cannot be used directly. Since it is a fertile material, it can be only used with added fissile material that can be enriched Uranium, Plutonium or Uranium-233 (obtained after irradiation of Thorium). Thorium absorbs the neutrons, which can more efficiently produce more Plutonium in Fast Breeder Reactor for a faster growth.

Therefore, using Thorium in the first, or an early part of second stage of nuclear power programme will adversely affect the rate of growth of nuclear power generation capacity in the initial periods. Due to these reasons, large scale deployment of Thorium was postponed till the later part of the second stage. Thorium is to be introduced only at an optimal point during operation of Fast Breeder Reactors in the second stage.  Thorium, for power generation is to be used mainly in the third stage

https://www.gktoday.in/wp-content/uploads-back/three-stage-nuclear-power-programme.png

Thus, the ultimate objective of the above programme is to create capacity to use Thorium for sustainable production of nuclear energy and make India energy independent.

Current Status: India’s AHWR

In 1984, India had built Purnima II, the first reactor of the world that handled U-233, part of the thorium fuel cycle. In 1996, India’s KAMINI wnet critically, which is only presently operating U-233 fuelled reactor operating in the world. At the same time, India is also working on several thorium reactor designs such as Compact High Temperature Reactor, the Innovative High Temperature Reactor, the Indian Molten Salt Breeder Reactor, and most famously, the Advanced Heavy Water Reactor.  In February 2014, India had announced design completion Advanced Heavy Water Reactor (AHWR) and it was said that by 2016, India will build a 300 MW prototype.  Further, it was also projected that the first megawatt of electricity would be generated by 2025. The AHWR will be fuelled by a mix of uranium-233 and plutonium — which will be converted from thorium by previously deployed and domestically designed fast breeder reactors. Currently, the projected date of creating energy from AHWR goes in 2030s. {read this for further knowledge}

We further note that India is developing two types of AHWR viz. AHWR and AHWR-LEU, where LEU stands for Low Enrichment Uranium.  Both the AHWR and AHWR-LEU use thorium-based oxide fuels, with the AHWR using both UO2/ThO2 and PuO2/ThO2 fuels simultaneously, while AHWR-LEU uses only UO2/ThO2 fuel.

Liquid Fluoride Thorium Reactor (LFTR)

The liquid fluoride thorium reactor is a modern incarnation of Thorium cycle based breeder reactor. The fuel used in such reactors is fluoride-based, molten, liquid salt of Thorium. The most notable and interesting thing about these Lifters (LFTRs, as they are spoken) is that they can achieve high operating temperatures at atmospheric pressure and can work at atmospheric pressure. This property changes the economics of nuclear power. In the light water reactors, the water deployed is under extremely high pressure. This implies that the light water reactors need to be sheathed in steel pressure vessels and placed in fortress-like containment buildings. The LFTR does not need all these.

In comparison to AHWR, LFTR offers several advantages of economy and ease of installation of nuclear reactor. The development of the LFTR could offer many advantages including the potential for low cost manufacture and very rapid scalability. Question is-Why India does not go for LFTR instead of AHWR? This question has not been clearly answered by Indian officials or policy makers. We note here that these days, China is very much interested in Thorium LFTR. All we can do is to hope that India will also appreciate the considerable advantages of Thorium LFTR over solid-fuel-rod Thorium systems which have many of the shortcomings of conventional MOX-fuel reactors.