Akwaaba!

Attributes of Nuclear Energy

Introduction
I wish to state that the facts and figures used in this or any subsequent discussions are from competent and verifiable sources such as the Inter-governmental Panel for Climate Change (IPCC), the ExternE Project of the EU-15, several scientific institutions, and certain eminent individuals.

Let us first refer to the Kyoto Protocol, which requires the industrialized countries, the main culprits of climate change, to curb their carbon emissions to save the earth from the ominous catastrophe. In view of that, the working group on the Mitigation Options of the IPCC that met in Accra in 2001 proposed the use of carbon-free technologies based on solar, wind and nuclear energies. The report also states that solar and wind energies are diffuse and so intermittent. On the other hand, nuclear is described as a mature option that can effectively replace coal for generation of base-load electricity, provided public concerns (radiation, cost, Chernobyl and high-level wastes) are addressed.

Such concerns are fuelled by misconception, and without some basic knowledge about nuclear reactors, it is not easy to explain the Chernobyl accident (a synonym of nuclear safety) in the right perspective without comparing it to the other major nuclear accident that happened at the Three Mile Island in Pennsylvania in the USA in 1979. So facts and figures are used here to lessen people’s fear on this option in this era of nuclear energy.

Safe and Clean
When it was announced in the House of Commons in London at the beginning of 2008 that several new reactors would be built, the following attributes for nuclear energy were used: “safe, clean, affordable and reliable energy to meet the twin challenges of energy security and climate change”. Of course, the announcement invoked the anger of many people. Against this backdrop, it is worth mentioning the views of the following iconic environmentalists Prof. James Lovelock and Dr. Patrick Moore. The former, who is now 88 years old, can be described as the father of the Green Movements. Please see for your perusal his views in Attachment-2.

Dr. Moore, a co-founder of Greenpeace, said before the U.S. House Congressional Panel on Energy Resources in April 2005 that: “There is now a great deal of scientific evidence showing nuclear power to be an environmentally sound and safe energy.” An example of such scientific evidence could be the ten-year ExternE Project of the EU-15. It was on the external costs (socio- environmental damages) brought about by fuels used for power generation. The results in Table 1, show that nuclear is more environmentally friendly than hydro even in cold countries. Hence in the tropics, where dams are the sources of various water borne diseases, nuclear should be an attractive option.

To underline the fact that nuclear is safe and clean, and that coal is the problem for the environmental agencies and the IPCC, let us look at coal and nuclear plants, each with an output power of 1000MWe (about the designed output of Akosombo). A 1000MWe coal plant requires daily about 8000 tons and emits daily several thousand tonnes of emission made up of carbon dioxide, sulphur dioxide, nitrous oxides and fly-ash laced with toxic metals such as lead and mercury. Such emissions degrade the environment and cause thousands of premature deaths annually in industrialized countries. It must be underlined also that coal-fired plants emit more radiation than nuclear power plants.

In contrast, a modern 1000MWe nuclear plant requires every 18-24 months only about 27 tons of fresh nuclear fuel. The radioactive products (high level nuclear wastes) created during operation are securely contained in the fuel, which is well isolated from the environment. It is written in the ExternE Project that: “Nuclear power involves relatively low external costs due to its low influence on global warming and of its low probability of accidents in the EU power plants,”
Another study of great interest undertaken by the Paul Scherer Institute in Switzerland was on ‘Accidental Deaths’, where the number of deaths for a given energy source used in power production was compared to the amount of electric energy produced by the source. The result in Fig 1 shows that nuclear has the least number of accidental deaths or accidents, and that agrees with the findings of the ExternE Project. The worst case is for hydro. Certainly the frequent deaths associated with the Akosombo Dam give credence to the results of this study.

Please compare closely Table 2 with Fig. 2 to appreciate that in countries such as the UK, the USA and France, with a lot of nuclear industries, about 84% of their background radiation exposure is from natural sources, out of which radon, (ubiquitous gas) accounts for about 50%. The remaining 16% of the background radiation is man-made, out of which sources from hospitals alone account for about 15% (about 12% from X-ray and 3% from Nuclear Medicine). The last 1% is due to commercial products (TV and smoke detectors), radioisotopes used in industries and irradiation from nuclear industries. It is a fact that the amount of radiation people receive from nuclear industries in one year is far less than what they receive in an hour of watching TV or travelling by air.

Abundant, Affordable and Reliable
Nuclear produces electric energy more abundantly than any other option, and it does so with a very small amount of fuel. If the said 27-ton uranium fuel needed for about 18-12 month operation is 3.5% enriched then the weight of the actual fuel (isotope U-235) that undergoes fission to produce the necessary heat is only 945kg. I must also add that, if the used or spent fuel (27 ton) is recycled, about 96% of it can be reused.

The fact that energy released in fission is very colossal, can be explained from Albert Einstein’s famous equation (E=mc2). It shows that a small loss of mass is converted to an enormous amount of energy because the ‘c’ in the equation is the speed of light, a very large figure (c=300 000 000meter per second) before it is squared. If nuclear generated electricity is so abundant, it has to be affordable and dispatch-able (or reliable). In other words, nuclear energy is said to have a very high capacity factor.

Capacity Factor (CF) is the ratio of the actual energy generated by a given power plant in a year to its potential. A 1000MWe plant can potentially produce in a year 1000MWe x 8760hour= 8760GWh of electricity. The higher the CF, the higher is the returns on the investments made on the power plant.
A 1000MWe reactor, that works non-stop for some 18 months before it is stopped for 4-6 weeks for refuelling and maintenance, may have a CF of about 90%, and can produce annually about 7884GWh of electricity. Compare this to Akosombo (designed capacity of 1038MWe) that produced 3219GWh in 2003, - corresponding to a CF of less than 40% of its potential in that year. But where there is energy-mix, hydro is the ideal option for peak load generation because it can be brought on or off line more instantaneously than others
The CF for wind power ranges mainly from 20-35%, and 15-25% for solar power. In the BBC News World Edition, posted on the website on 25-02-05, Professor Pfaffenbeger of the Bremen Energy Institute in Germany said: “The specific problem is that you cannot always have the wind when you need the energy”. He added: “That is why at the moment more than 15% of our capacity is wind power, but produces only 3% of our energy”. In fact the average CF for wind power in Germany is about 20%.

The Production Cost of a power plant depends on its capital, operation and maintenance and fuel cost (see Fig. 3). For nuclear and gas, the capital cost accounts for 60 and 16% whereas the fuel cost accounts for about 16 and 72% of the production cost respectively. Hence it is cheap to build a gas plant, but very expensive to run it. Let us note that natural gas is so tied to oil that, the price of oil mostly moves in tandem with that of gas. So if the price for a barrel of oil, which was about $30-40 in March, 2003 is now over $125, it can be concluded that the price of gas has at least doubled, making NP very attractive option. That could be the principal reason for the resurgence of nuclear energy worldwide.

Fig. 4 shows that in the EU-15 nations (with the exception of the UK), not endowed with indigenous energy sources like the USA or Canada, nuclear is the largest single option for power production at affordable cost. In the UK nuclear was competitive with gas and coal. A UK Royal Academy of Engineering’s report of 2004, given in Table 3, shows that in that year the unit costs in pence/kWh for gas, nuclear and coal were 2.2, 2.3, and 2.5 respectively. But when carbon-tax was taken into account, the unit costs for gas and coal generated electricity became 3.4 and 5.0 pence/kWh respectively.


Dr. Isaac Acquah,

Vienna, 06-08-2008

 

 

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