In India to achieve a higher economic growth rate, the electricity generation capacity has to increase considerably in the coming years – and for this we need to fully utilise all options that are available. The challenges for hydrocarbon based fuels are adverse effect on the climate and limited resources. Thus, there is more focus to utilise the nuclear energy option and it should contribute in more share. Major goal of the Department of Atomic Energy in India has been to carry out research and development in this field, to develop the required technologies to harness nuclear energy and to install nuclear power stations. India stands at the thirteenth place world-wide in generating electricity from nuclear source. (Table 1)
India is vigorously pursuing the nuclear energy programme. Tarapur Atomic Power Plant-1 was the first Nuclear power plant in India. This plant is situated in Boisar, Maharashtra since Oct-1969. Presently, India has 22 operating reactors in 7 nuclear power plants with an installed capacity of 6780 MW (Table 2). Nuclear power produced a total of 35 TWh and supplied 3.22% of Indian electricity in 2017. The availability factor of Indian reactors was 69.4% in the years 2015-2017. (Table 3)
Nuclear generation has increased by 22.90% during 2019-20. The Atomic Energy Commission envisages a target of 500 GW of nuclear energy generation by 2060. In India, there are 22 operating commercial nuclear power reactors with an installed capacity of 6780 MW. At the end of December 2020, the gross generation is 33,948 Million units, having capacity factor 84% and availability factor 87%. Out of 22 operating reactors, 14 reactors of the Nuclear Power Corporation of India Limited (NPCIL), viz. TAPS-1&2,RAPS-1 to 6, NAPS-1&2,KAPS-1&2 and KKNNP-1&2 with total installed capacity of 4,380 MW, are fuelled with imported fuel and are under IAEA safeguards. Eight reactors, viz, MAPS-1&2, KGS-1 TO 4, TAPS-3&4 with total installed capacity of 2,400 MW, are fuelled with domestic fuel. Many more reactors under various stages of construction totaling 6,200 MW capacity and another twenty are in different stages of planning and implementation.
Several analysts have argued that given India’s limited and low-grade uranium reserves, the development of the nuclear programme beyond 10,000 MW would imply increasing dependence on uranium imports. However, this viewpoint tends to overlook the logic of India’s three stage nuclear power programme planned by Dr. Homi Bhabha, which envisages large-scale utilization of India’s significant thorium reserves. Uranium dependency would be for a limited period of time till India graduates to the thorium cycle. As far as India’s three stage nuclear power generation is concerned, we are just at the beginning of the second stage. India is among the very few countries pursuing this technology.
The potential of nuclear power
The challenge for the nuclear community is to assure that nuclear power remains a viable option in meeting the energy requirements of the century. It could be a major provider of electricity for base load as well as for urban transport in Megacities. It can play a role in non-electric applications in district heating, process industries, maritime transport, water desalination, hydrogen production, and for applications in remote areas. It can contribute substantially to the security of energy supply and it has the potential to be an almost inexhaustible long-term energy resource through the use of breeder reactors.
Authoritative comparative assessments illustrate the potential of nuclear power to mitigate energy-related health and environmental damage, it can be shown to be one of the most environmentally acceptable means of generating electricity. If external factors, such as the societal costs of climate change, environmental damage, and health effects were included in all analyses, a clear nuclear advantage would arise over fossil fuels and the economic competitiveness of nuclear power in a radically changing financial environment would escalate.
If a significant contribution from nuclear power is to take place by the middle of the next century, a large amount of new generating capacity would be required, averaging as high as 20 new units annually. There are a number of issues relevant to the fuel cycle and the type of reactor desired that must be dealt with now, in order to provide the best conditions for an increased nuclear role. Following are the key factors that determine the future fuel cycle and nuclear reactor strategies.
Maximizing resource utilization: Known and likely resources of uranium should assure a sufficient nuclear fuel supply in the short and medium term, even with reactors operating primarily on once-through cycles with disposal of spent fuel. However, as uranium demand increases and reserves are decreased to meet the requirements of increased nuclear capacity, there will be economic pressure for the optimal use of uranium in a manner that utilizes its total potential energy content per unit quantity of ore. A variety of means are available to accomplish this during the enrichment process and at the operational stage. Thorium could also be a valuable energy resource in the longer term.
Uranium fuel cycle: Isotopic separation technology enables lowering the U-235 content in the enrichment process waste tailings. This results in extraction of more of the original 0.7% fraction of this fissionable isotope existing in the natural uranium ore that consists primarily of non-fissionable U-238. At the operational stage, higher fuel burn-up cycles will utilize more of the U-235 contained in the enriched uranium fuel elements – concurrently reducing the amount of spent fuel relative to the energy produced. However, reprocessing of spent fuel instead of disposal would allow the recycling of generated plutonium through mixed oxide fuel in thermal reactors as well as in fast breeder reactors and also make available uranium with its fissionable isotopes that are contained in spent fuel. Recycling provides the best use of available uranium resources.
Thorium fuel cycle: Although uranium is likely to remain the main natural resource for nuclear power systems, in the longer term the use of fertile thorium as a feed material is possible. While uranium contains a fissionable isotope, thorium does not. It must be enriched with either fissionable U-235 or plutonium to start the fuel cycle. The U-233 that is subsequently generated in the reactor from thorium conversion is fissionable. The thorium fuel cycle, with its lower operating fuel temperatures, has advantages in the physical performance of fuel elements and also with respect to the characteristics of the core physics. The existence of indigenous thorium in a number of countries that have limited uranium deposits would make this an attractive option. Thorium-based fuel cycles have been developed in a number of countries.
Maximizing economic benefits: As fuel costs are relatively low, reduction of overall costs by decreasing development, siting, construction, operation, and initial financing expenses is essential to the overall economic viability of nuclear energy. Removing the uncertainties and variability in licensing requirements, particularly before commissioning, would allow for more predictable investment and financial strategies.
Development, Capital costs: The need to reduce high initial capital costs will encourage economies in siting and construction. It will lead to multi-unit sites at existing locations that will also maximize infrastructure investments. Plant size and unit power levels will be matched to regional needs and the choice of suppliers will be based on long-term economics rather than on short-term advantages. In the operational area, reduction in costs will require high availability and load factors brought about by high quality systems, long core fuel cycle periods, short shutdown times and the ability to rapidly return to power. There will be a continued evolution of separate organizations providing various plant and fuel cycle services, particularly on a regional basis.
Licensing: Some of the high capital costs of new facilities and extended construction periods are related to the uncertainties and demands in licensing requirements. Uncertain waste management and decommissioning requirements and costs deter investments. These factors may lead to a rationalization of the licensing process leading to more certainty in regulation and a concurrent decrease in the time from site selection to operation.
Finance: Innovative and novel investment strategies will be needed to meet evolving and changing investment goals. The large initial capital investments required for nuclear power projects could be easier to raise in the framework of multinational funding arrangements. Build, operate and transfer arrangements maybe used in developing countries that allow for adequate returns on non-domestic investments before shifting ownership.
Maximizing environmental benefits: Although nuclear energy has distinct advantages over today’s fossil burning systems-in terms of fuel consumed, pollutants emitted and waste produced-further reducing environmental concerns can have a major influence on public attitudes. Reactor systems and fuel cycles can be adjusted to minimize waste production. Advanced technologies to contain and immobilize high-level waste are under development. But, of most significance, programmes are currently in place to demonstrate the adequacy of deep underground disposal of high-level waste. The necessary technology exists for these reactors and their associated chemical separation plants. Thorium fuel cycle results in less long-lived isotopes and lower disposal requirements.
Maximizing reactor safety: With more than 442 reactors operating for more than 20 years on average, nuclear power generally has an excellent safety record. Three accidents-Three Mile Island in 1979, Chernobyl in 1986 and Fukushima in 2011, demonstrated that a very severe nuclear accident has a potential to cause national and regional radioactive contamination. The safety concerns coupled with the associated regulatory requirements will, in the near term, continue to exert a strong influence on nuclear power development. In order to reduce the magnitude of real and perceived accidents, a number of approaches will be used in new facilities. Enhancing the integrity of the reactor vessel and reactor systems will also decrease the likelihood of onsite consequences. International collaboration will provide reactor and system designs that incorporate globally accepted safety and engineering standards. It will contribute to assuring safety worldwide and encourage country-of-origin licensing as an acceptable basis for national licensing of imported reactors. A wide range of international agreements, non-binding safety standards and international review and advisory services already exists. The safety record of Indian nuclear plants is no exception – and experience gained in overcoming the consequences of a few incidents has helped confirm validity of the safety features. Though these safety standards are excellent, there is a need to further improve them – to obviate the need for public evacuation after a severe accident, which contributes to the negative public mind-set about nuclear energy.
Important safety issues are radiation effects, radiation waste management, decommissioning and accident risks in reactors. These have been adequately addressed and improvements continue. The radiation doses to operating personnel and the public during normal operation are well within limits prescribed by the Atomic Energy Regulatory Board. Nowhere in the world have the effects of radiation been noticeable in normal operation of nuclear facilities. Radiation waste is isolated from the biosphere while the gases from fossil plants are entering the atmosphere. India developed the technology for radiation waste management well in time and new breakthroughs are not required.
Safety features of the Indian Thorium Advanced Heavy Water Reactor Design: The Indian thorium fuelled Advanced Heavy Water reactor has been designed with safety as top priority. It has several innovative and passive safety features that would effectively shut down the reactor in the event of any foreseeable accident. Along with the conventional active shutdown capabilities such as scramming or flooding the reactor with coolant, the reactor also has several passive shutdown systems that will automatically activate in the event of a hot shutdown, prolonged shutdown, or Loss of Coolant Accident (LOCA). During normal operation, coolant is circulated by natural convection instead of pumps, so a loss of power will not cause a loss of coolant. If a loss of coolant accident did happen, the rising temperature would cause the automatic release of a reactor poison into the system, which would kill the reaction. If this system was to fail, and the temperature continued to rise, the large gravity driven water pool at the top of the reactor building would automatically start flooding the bottom the reactor cavity, effectively submersing the whole reactor core. If the reaction rate continues to increase, there is enough coolant to keep there is enough coolant to keep the reaction in check for 72 hours, more than enough time for the operator to step in and manually shut down the reactor.
Satisfying key policy needs: Energy independence along with non-proliferation concerns and excess military plutonium are high on the list of policy factors at the national and international level that strongly influence the nuclear option. In a political world, energy independence through security of energy supply and a balanced mix of energy sources are paramount national interests. With nuclear power, security of supply concerns is lessened as adequate strategic inventories can be relatively easily established with low financial costs. Today’s global energy mix has an almost 90% fossil component. Clearly, where indigenous fossil fuel resources are lacking, nuclear energy can contribute substantially to the energy mix in India.
The overall safety is much better than it was 10 years ago, but we still have vulnerabilities in safety, as well as in security. In the nuclear domain, the role of the government goes beyond setting national energy goals. Nuclear energy, if produced safely, offers promise. The requirement hence is to fast-track civilian nuclear expansion while maintaining the highest standards of nuclear safety and security. Nuclear power has the potential for playing a major role in India’s quest for more power.
Nuclear power is likely to remain a major part of India’s energy plan. Though it has had some success, notably the development of some expertise over most steps in the nuclear fuel chain, India’s atomic energy programme has not achieved any of its promises. The most important failure has been that after more than 70 years, nuclear power constitutes only less than three per cent of the nation’s electricity generation capacity. To some extent, this has been a result of international sanctions imposed on India. The limited amount of nuclear electricity generated has been at a relatively high cost.
India aims to supply 9% of its electricity needs with nuclear power by 2032 and 25% by 2050. The reactor construction costs have not dropped over the years, and despite their claims of improved construction practices, show little evidence of learning. India is blessed with aplenty of sunshine and a nearly inexhaustible resource of Thorium. Our future depends on how efficiently these two resources are utilised. With India’s entry into international nuclear cooperation, the opportunity for a rapid growth in the installed capacity helps in accumulating fissile inventory at a faster pace. In the meantime, several enabling indigenous technologies have been developed for thorium utilization. Focused developments in Solar and Thorium energy can lead to a stage, when India will not have to look onwards for meeting its energy demands for several centuries, in harmony with environment. We should not protect the environment; we should create a world where the environment doesn’t need protection.
Dr. Gopalkrishna D. Kamalapur
The author is a Professor at the Department of Electrical and Electronics Engineering in S D M College of Engineering and Technology, Dharwad-580002