Nuclear Energy is essential for the survival and growth of modern human civilization. A reasonably good correlation exists between per capita energy consumption and quality of life, as indicated by the UN Human Development Index. India’s, three-stage nuclear energy program plays a crucial role in this regard. Read further to know more.
The Three-Stage Nuclear Program
The importance of nuclear energy, as a sustainable energy resource for our country, was recognized at the very inception of India’s atomic energy program more than four decades ago. A three-stage nuclear power program, based on a closed nuclear fuel cycle, was then chalked out
The three stages are:
- Natural uranium-fuelled Pressurised Heavy Water Reactors
- Fast Breeder Reactors (FBRs) utilizing plutonium-based fuel,
- Advanced nuclear power systems for utilization of thorium.
Stage 1: Pressurised Heavy Water Reactors
- The first stage involves using natural uranium to fuel PHWR to produce electricity and producing Plutonium-239 as a by-product.
- Kindly note here that the PHWRs were chosen for the first stage because, in the 1960s, India had an efficient reactor design in terms of uranium utilization.
- It was calculated that rather than going for the creation of Uranium Enrichment Facilities, it would be wiser to create heavy water production.
- 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 by-product plutonium-239 would be used in the second stage. First Stage: Following Reactors
- Boiling Water Reactor
- Pressurized Heavy Water Reactor
- Pressurized Water Reactor
Stage 2: Fast Breeder Reactors
- The second stage involves using plutonium-239 to produce mixed-oxide fuel, which would be used in Fast Breeder Reactors. Plutonium 239 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.
Fast Breeder Reactor:
- First at Kalpakkam in TN
- Uses Pu-239 as fuel and u-238 is converted into Pu-239
- Also known as the Fast Neutron Reactor
- No moderator
- Coolant is liquid Na
Stage3: Advanced Heavy Water Reactors
- The main purpose of stage 3 is to achieve a sustainable nuclear fuel cycle. The advanced nuclear system would be used as 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, the use of Thorium in the 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 with Uranium, Plutonium, or Uranium-233 (obtained after irradiation of Thorium).
- Thorium absorbs neutrons, which can more efficiently produce more Plutonium in a Fast Breeder Reactor for faster growth.
- Therefore, using Thorium in the first, or an early part of the second stage of the nuclear power program 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 until the later part of the second stage. Thorium is to be introduced only at an optimal point during the operation of Fast Breeder Reactors in the second stage.
- Thorium, for power generation, is to be used mainly in the third stage.
Goals of The Third Stage
Technologies pertaining to the utilization of thorium have been under development, mainly at BARC, right since the inception of our nuclear power program. The third stage of our program has to necessarily meet the following goals:
i) Utilisation of thorium as fuel on a commercial scale.
ii) Large-scale deployment of nuclear power in the country.
iii) Achieving good economic performance as compared to alternate options for energy generation.
iv) Attaining higher levels of transparent safety, through optimal utilization of inherent and passive safety features.
v) Utilising the proliferation-resistant potential of the thorium fuel cycle to the full extent.
vi) Providing adaptability to non-electrical applications, in particular, desalination and high-temperature processing applications, including those for the generation of non-fossil fluid fuels.
For a large country like India, long-term energy security, mainly based on indigenous resources, is an important and inevitable need, from economic as well as strategic considerations. Nuclear energy plays a vital role in this regard.
Article written by: Vivek Rajasekharan