Environmentally friendly electricity from nuclear energy

By Dr Zivayi Chiguvare
March 2014
Other Articles

Nuclear energy is usually associated with the nuclear bombs that destroyed the cities of Hiroshima and Nagasaki at the end of the Second World War, the Chernobyl accident in the Soviet Union, and the Fukushima disaster in Japan. Seldom is nuclear energy associated with the electricity that we use in our homes and industries on a daily basis. Many people have heard about radioactivity and the harmful effects that this can have to humans, including how cancer causing it is, and how reproductive health would be compromised by exposure to such radiation. There is however a brighter side to nuclear energy.

 

 

Nuclear energy is the only proven technology that can deliver base load electricity continuously on a large scale, 24 hours a day, 7 days a week, regardless of the weather, without producing carbon dioxide emissions, carbon monoxide, sulphur oxides nor nitrogen oxides to the atmosphere. Other parts of the nuclear fuel cycle do produce carbon, but uranium-fuelled nuclear energy produces comparable amount of carbon across its life cycle as hydro and a bit less than wind energy, and significantly less than solar power and all forms of fossil-fuelled electricity. One kilogram of uranium-235 can theoretically produce about 20 terajoules of energy (2×1013 J), assuming complete fission; as much energy as 1500 tonnes of coal. Fuel transportation costs are less, and there is less impact on our environment from mining. Nuclear power plants require very little space and can be situated close to where their power output is needed.

 

 

Energy / Power Source

Life-cycle emissions

(gram-equivalents of CO2 per kWh)

1

Hydropower

2 to 48

2

Nuclear power

2 to 59

3

Wind power

7 to 124

4

Solar photovoltaic power

13 to 731

5

Natural gas fired power

389 to 511

6

Coal fired power

790 to 1,182

 

 

Table 1 Lifecycle emissions per energy source.  Source: IEA

 

In these days of advocacy towards low carbon economies, many countries are resorting to generating electricity using nuclear energy, as an easier way of becoming self sufficient in terms of energy provision, and reducing dependency on imported fossil fuels.  A huge demand for low-cost, environmentally-friendly alternative energy sources is envisaged in the near future, and nuclear power is expected to satisfy this requirement.  Many parts of the developing world are short of power and are building large numbers of nuclear power stations.

 

The first commercial nuclear power stations started operation in the 1950s. As of January 2014, 30 countries worldwide were operating 436 nuclear reactors for electricity generation, with over 370,000 MWe of total capacity.  About 72 new nuclear plants are under construction in 15 countries with an installed capacity of 72,612 MWe. Nuclear power plants provided 12.3 percent of the world’s electricity production in 2012. There are about 240 research reactors used for the production of medical and industrial isotopes, as well as for training, in 56 countries, with more under construction. The use of reactors for marine propulsion is mostly confined to the major navies, providing power for submarines and large surface vessels.

 

By January 2014, 13 countries relied on nuclear energy to supply at least 25 % of their total electricity.Thisis a large amount of energy. France gets around 75 % of its power from nuclear energy, while Belgium, Czech Republic, Hungary, Slovakia, Sweden, Switzerland, Slovenia, Ukraine South Korea, Bulgaria and Finland normally get more than 30% of their power from nuclear energy. In the USA, UK, Spain and Russia almost 20 % is from nuclear, while Japan relies on nuclear power for about 25 % of its electricity. In fact, through regional grids, many more countries use nuclear-generated power. For instance, Italy and Denmark get almost 10% of their power from nuclear. Even within the Southern African Power Pool (SAPP) some of the electricity imported from South Africa could be from nuclear sources.

 

Nuclear power stations work similarly to fossil fuel-burning stations, except that a “chain reaction” inside a nuclear reactor produces the heat instead. The reactor uses Uranium rods as fuel, and the heat is generated by nuclear fission: fast neutrons bombard the nucleus of uranium atoms, which split roughly in half and release energy as heat. Uranium-235 is the only naturally occurring fissile isotope. Carbon dioxide gas or water is pumped through the reactor to take the heat away, this then heats water to make steam. The steam drives turbines which drive generators. Modern nuclear power stations use the same type of turbines and generators as conventional power stations.

 

Uranium mines operate in twenty countries, though about half of world production comes from just ten mines in six countries, namely Kazakhstan, Namibia, Canada, Australia, Niger and Russia. The Husab deposit in Namibia is one such feasible Uranium ore body.  The ultimate available uranium worldwide is believed to be sufficient for at least the next 85 years.

 

 

 

 

Fig. 1 (a) World’s known reserves; (b) 27,851 tons of Uranium was produced in 2011

 

Uranium itself isn’t particularly radioactive, so when the fuel rods arrive at the power station they can be handled using thin plastic gloves. A rod can last for several years before it needs replacing. Nuclear power costs about the same as coal, but it produces small amounts of very dangerous waste which must be sealed up and buried for many thousands of years to allow the radioactivity to die away. During that time it must be kept safe from earthquakes, flooding, terrorists etc. This is difficult. Nuclear power is reliable, but a lot of money has to be spent on safety - if something goes wrong, a nuclear accident can be a major disaster.

 

All parts of the world are involved in nuclear power development: The Chinese government plans to increase nuclear generating capacity to 58 GWe with 30 GWe more under construction by 2020. India’s target is to have a  14.5 GWe nuclear capacity on line by 2020 as part of its national energy policy. Russia plans to increase its nuclear capacity to 30.5 GWe by 2020, using its world-class light water reactors. Finland and France are both expanding their fleets of nuclear power plants with the 1650 MWe EPR from Areva, two of which are also being built in China. Several countries in Eastern Europe are currently constructing or have firm plans to build new nuclear power plants (Bulgaria, Czech Republic, Hungary, Romania, Slovakia, Slovenia and Turkey).  UK government energy paper in mid-2006 endorsed the replacement of the country’s ageing fleet of nuclear reactors with new nuclear build, and four 1600 MWe French units are planned for operation by 2023, etc.

 

In Africa only South Africa is committed to plans for further conventional nuclear power reactors, and Nigeria has sought the support of the IAEA to develop plans for two 1000 MWe reactors. Namibia is one of the top five world producers of Uranium for power plants, but does not have its own nuclear power plant. Namibia however is a heavy importer of electricity (up to 60 %) from the SAPP, and this for only 34-5 % of her population with access to electricity. The demand for electricity will continue to increase in the foreseeable future. It must be noted that Uranium is not renewable; once we have dug it all up and used it in a nuclear power plant, it is not there anymore, it does not regenerate. It will not be available for future generations. PF

 

Sources:

Richard (Rick) Mills, rick.mills@aheadoftheherd.com; www.aheadoftheherd.com

http://swakopuranium.com/ob-au-gen.php

WNA, data to publication date.
IAEA.
Nuclear Engineering International, May 2013 (load factors)