• Electrical India
  • Oct 5, 2015

Nuclear Power
And The Challenge Of Climate Change

The challenge is that we need to reduce greenhouse gas emissions and other pollutants – and yet provide affordable power to allow for improved standards of living to the global population...

- Shah Nawaz Ahmad

 Climate change is now a universal concern. The story goes something like this:

  The Greenhouse Effect: Carbon dioxide is transparent to the Sun’s light, but absorbs and re-radiates the heat energy emitted by the earth.

  Global Warming: The re-radiated heat warms the Earth until the net energy influx and output are balanced.

  Climate Change: The additional heat energy has a complex effect on the climate and consequentially the biosphere.

  This theory is not new, has been developing for a long time. Natural greenhouse effect is universally accepted. Without natural greenhouse effect, average global temperatures would be around 33oC colder. However, in recent years concentration of carbon dioxide (CO2), methane and other greenhouse gases (GHGs) in the atmosphere has been rising. At least 80% of the world’s electricity must be low-carbon by 2050 to give the world a realistic chance of keeping warming within 2oC according to the latest (5th) IPCC Synthesis report. The crux of the matter is, fossil fuel based power generation is one of the largest contributors to climate change through carbon dioxide emission.

  It is also a well known fact that there is a strong direct correlation between per capita energy consumption and Human Development Index (HDI). As developing nations seek to raise their standards of living, the world will need greatly increased energy supply in the next 20 years, especially cleanly-generated electricity. Also, we need to recognise that electricity demand is increasing twice as fast as overall energy use and is likely to rise by more than two-thirds between 2011 & 2035. The challenge is that we need to reduce greenhouse gas emissions and other pollutants – and yet provide affordable power to allow for improved standards of living to the global population.

  Indian cities are amongst the most polluted cities in the world, causing immense damage to health. Also, India's per capita electricity consumption is amongst the lowest in the world. Thus, there is an urgent need to increase electricity generation, as also to clean up the environment.

  So what are the options for non-polluting, carbon free power generation?

  Hydro is the classic renewable but have geographical and water use limitations. Presently solar & wind are on the upsurge. But let's face the facts. Solar & wind generated electricity is intermittent. Wind’s capacity factor is around is 30%, and solar is at 25%. This is not likely to improve substantially till viable energy storage devices are developed.
This leaves nuclear as a principal well established and proven alternative, particularly for bulk electricity production. There are already 437 reactors in operation world-wide, providing 11% of the world's electricity. Another 65 reactors are under construction.

  Given the present scenario and severe need for electricity, in the near & intermediate term, most countries will need to have a power mix, which will need to include fossil fuels, renewables & nuclear. In the long term, fossil fuels will need to be eased out, and greater share has to be taken by renewables and nuclear. India is also following this route, the debate is how much of which?

  And if we follow this pragmatic route, we find that renewables and nuclear stand on the same side of the carbon divide. The nuclear industry holds a unique place in the world economy, both in its: fundamental benefits of delivering clean, reliable, affordable energy on a large scale; and in the challenges it faces, – which range from the technological sophistication of its products, high capital cost of its plants, complexity of its supply chain, and – concerns raised by some sections of the general public over this form of energy.

  It is also important to remember that nuclear energy also plays a vital role in other sectors too. Nuclear and radiation technology is vital for more than just providing electricity. It also has applications in medicine, industry, transport, agriculture, and it helps us learn more about our universe and can even be found inside your home.

  For example, more than 30 million nuclear medicine procedures are carried out throughout the world every year. These involve the use of radioisotopes, such as technetium-99m, usually produced in research reactors. Russia keeps its shipping lanes open during winter with a fleet of nuclear-powered ice-breakers. NASA’s Curiosity Rover uses plutonium as an energy source. Many household smoke detectors use the radioactive isotope americium-241. A nuclear reactor produces and controls the release of energy from splitting the atoms Uranium and a few other elements.

  The principles for using nuclear power to produce electricity are the same for most types of reactors. The energy released from continuous fission of the atoms of the fuel is harnessed as heat in either a gas or water, and is used to produce steam. The steam is used to drive the turbines, which produce electricity (as in most fossil fuel plants).

Schematic of a nuclear electricity generating power plant...

  I would like to add that radioactivity is a natural phenomenon and there have been many natural reactors. The world's first nuclear reactors operated naturally in a uranium deposit about two billion years ago. These were in rich uranium ore-bodies and moderated by percolating rainwater. The 17 known at Oklo in West Africa, each less than 100 kW thermal, together consumed about six tonnes of that uranium. It is assumed that these were not unique worldwide.

  Any electricity generation policy will seek to deliver reliable, safe, affordable and clean power to its people. Let us see how the various power options fit into this scheme of things. Energy security and energy independence are also of concern to planners.

  One measure of reliability is the Overall Plant Load Factor. The world-wide average load factors are in the range of 25% for Solar, 30% for wind, 65% for coal and 90% for nuclear. Hydro capacities are affected by water use policies and rainfall, so the range can be very wide. This intermittency brings with it costs – economic and environmental, i.e., the need for backup generation. 

  Nuclear is a bulk production (base load) source suitable for industrial & process requirements, while renewables like solar and wind are more suitable for distributed loads. These high load factors also help the economics of nuclear plants. (The need of the hour for renewables is to develop bulk electricity storage systems). Indian nuclear power plants have regularly operated at 90% capacity factor.

  Nuclear power plants are perhaps the safest in terms of death-rates per Terra-Watt-hours (TWh) of electricity production. 

Typical values are:-

  One of the reasons for the above is the degree of tight regulation of the industry by national regulators, wide sharing of knowledge of safety standards & good practices encouraged by UN bodies like the IAEA (International Atomic Energy Agency) and International Industry organisations like WNA (World Nuclear Association) & WANO (World Association of Nuclear Operators).

  A measure of the international confidence in nuclear power, let me state that before Fukushima accident worldwide there were 434 reactors in operation, 72 under construction and 173 were planned. As of March 2015 the figures are: In Operation-437, Under Construction-65, and Planned-165. Nuclear continues to generate 11% of the world's electricity as before. Even in Japan, nuclear restarts are now being authorised.

  Fortunately nuclear accidents have been very few & far between. Though Fukushima got massive coverage press coverage, the point to note is that there have been no deaths due to radiation. In the other two major incidents, there were no deaths at TMI. In Chernobyl & 30 rescuers died (28 due to acute radiation exposure) & 100 rescuers were injured. Over 6000 children with thyroid cancers were reported, but luckily only 15 were fatal. (This was traced to intake of contaminated milk). There were no detectable cases of other cancers, incidence or mortality, that could be attributed to radiation from Chernobyl. These are the facts of the most severe of nuclear accidents.

  Radiation is a big subject, but just a few words here. The energy source of our renewables is the sun, which actually is generating energy through a nuclear fusion reaction! ‘The earth is the aggregate of fusion products’. Unstable fusion products undergo decay process & form stable elements. In a sense earth is the 'radioactive waste' from the fusion power plant in universe. That is why we see background radiation on earth, that is why we see natural reactors on earth, as mentioned earlier. Indian plant data shows that a nuclear power plant during normal operation adds more or less, to the background radiation; which is the typical figure internationally too.

  When we talk of waste, we need to talk both about the volume of waste, our ability to handle it and the ill effects of coming into contact with this waste. The quantity of fuel needed to generate a certain amount of power depends on its calorific value, and obviously if you put in a lot of fuel you would generate a lot of waste. Typically, a 1000 MWe (Mega Watt Electrical) plant needs 2,000,000 tons of coal, or 1,960,000,000 gallons of oil, or 27 tonnes of Uranium. A coal plant will generate, on an average 400,000 tons of ash, as well as considerable amounts of particulate matter and injurious elements such as As, Hg, Cr, Cd. In addition, it will produce 4- 5,000,000 tons of CO2 per year. {Carbon emissions impose a huge cost on society by threatening the basic elements of life --access to water, food production, health and the environment. Economists have estimated these 'social costs' at anywhere from US$8 per ton to as high as US$100 per ton of CO2. We do need to develop clean coal and carbon capture technologies}

  A typical 1000 MWe light water reactor will generate (directly and indirectly): 200-350 m3 low- and intermediate-level waste per year. It will also discharge about 20 m3 (27 tons) of used fuel per year, which corresponds to a 75 m3 disposal volume following encapsulation if it is treated as waste. Where that used fuel is reprocessed, only 3 m3 of vitrified waste (glass) is produced, which is equivalent to a 28 m3 disposal volume following placement in a disposal canister. Safe & secure storage of these, much smaller quantities, over a long period of time is now considered feasible and practical. (India has adopted the reprocessing route, so the lower volumes will govern in the country). Another thing we need to remember that when the life cycle CO2 balance of a plant is taken into account nothing is No-Carbon. Life Cycle Green House Gas Emission when measured as CO2 equivalent per GWh (Giga-Watt-hours) is estimated to be as follows;- Solar PV- 65, Nuclear-28, Wind-26 & hydro-26!! For fossil fuel it is:- Lignite-1069, Coal-888, Oil-735 and Natural Gas-500.

  The economics of nuclear power has been a point of discussion, for a long time. High capital cost of new plants requires long term financial instruments and tight project management and control of construction times. What works in favour of nuclear is high plant load factors achieved world-wide, long design life, low running costs, ready availability of Uranium & non-volatility in its price.

  Structured life extension programmes have resulted in increased operating lives of plants, typically from original 40 years' design life to around 60 years; with minimal monetary investment. Such plants also deliver cheap power. India's oldest plants Tarapur Atomic Power Plant (TAPP) Units 1 &2, I understand, supply the cheapest non-hydel power! New plants are being simplified in design, have longer design life, and are modular in construction, all of which should lead to more competitive plants. 

  Energy security remains a high priority for all nations, and this is equally true for India. Indeed the nuclear route, envisaging ultimate use of thorium can lead to Energy Independence for India. India has about 30% of the world's Thorium and the potential for power generation is huge (See figure). The Department of Atomic Energy (DAE) has worked strenuously, and today India is a world-leader in this area. Though commercial Thorium use is some way into the future, it nevertheless holds great promise.

  Thorium is not fissile; it needs to be converted to Uranium 233. Indian approach is the new classic 3 stage programme. The fuel from Stage 1 Thermal PHWR reactors is reprocessed and used in Stage 2 Fast Breeder reactors. During operation, the Thorium blanket in the reactor will be converted into fissile Uranium-233. (See figure).
India has a long-standing, comprehensive and robust nuclear programme, which covers all aspects of the nuclear fuel cycle. Currently, India is building several 700 MWe PHWRs & one 500 MWe FBR. This is an indigenous programme, where Indian authorities have designed & constructed the reactors & operate the same. This programme is well under way.

  The Manmohan-Bush deal opened the way for international nuclear commerce. In addition to the Russian reactors, India proposes to build nuclear power plants with the cooperation of France & USA. The intention is that these additional plants will increase nuclear power manifold, helping India to meet its climate commitments to a certain degree, while providing much needed electricity.

  However, acceleration of the nuclear programme and introduction of these different technologies throw up many challenges. These relate to the absorption of the technology itself, building the necessary man-power, arranging finances, liability and compensation issues, becoming part of the international nuclear regime and aligning Indian laws in harmony with International agreements and conventions.

  The Indian nuclear power track record, both of DAE/ NPCIL and the industry, bodes well for the success of this assimilation; but it remains a challenge nevertheless. In due course Indian entities can contribute in a significant way to international nuclear commerce. That would be a really win-win situation, for India and the world.

Shah Nawaz Ahmad is Senior Adviser, India, Middle East and South-East Asia World Nuclear Association.

What's your view on this article? Please comment your feedback!