Sunday, 19 June 2011

Is it Safe to Abandon Nuclear Power?

Shut Down Nuclear Power!
For weeks after 23,000 Japanese citizens were killed by the tsunami on 11th March 2011, the world’s attention was focussed on the unfolding drama at the Fukushima nuclear power plant.  As a result of the events at Fukushima there has been a widespread call for the closing down of nuclear power stations in Europe.  Germany has stated that they will decommission their nuclear installations in 2022; in a recent referendum Italy has voted against nuclear power and the question is being raised regularly in France.  Such is the groundswell of public opinion that it almost appears to be a political "no-brainer" to be against nuclear power.

I feel that, before these decisions are taken in such a highly emotional context, there should be a cool realistic assessment of the risks and benefits of nuclear power.  The perception of a risk is not necessarily related to the reality and since it hinges on probabilities and estimates of consequences it can be very subjective.  Nevertheless, Risk Management is well understood and practised widely in many branches of industry, finance and medicine and people working in the nuclear industry are using these techniques as part of their day to day activities.

A Good Safety Record?
Between 1952 and 2011 there have been six incidents worldwide which have been classified as level 5 or more. To put this into a frame of reference, the scale of seriousness goes from 1 to 7. A Level 5 incident is described as: “A limited release of radioactive material likely to require implementation of some planned countermeasures. Several deaths from radiation”

The description of a level 7 incident is: “A major release of radio-active material with widespread health and environmental effects requiring implementation of planned and extended countermeasures”.

Fukushima is currently classified as a level 5 incident, Chernobyl was classified as level 7, the only time that this category has been used. Three Mile Island in Pensylvania (in 1979) was classified as level 5.  As you can see from the link at the start of the paragraph there have been others but I think it is true to say that in the West the perceived danger from nuclear reactors is based on these three major incidents.

Since the start of civilian nuclear power in 1952 there have undoubtedly been deaths as a result of radiation, both locally and outside the plant boundaries, but especially amongst the workers involved in the task of making a site safe after a release of radioactive materials.  Because of the delays between exposure and the development of cancers, however, it is difficult to find any reliable figures concerning deaths caused by these incidents over 63 years of the history of nuclear power. Estimates for the number of deaths due to the Chernobyl meltdown, and subsequent fire, range from 4,000 by the Atomic Energy Authority to half a million by Greenpeace. 

UK Road Accident Fatalities
By comparison road deaths are well documented. In the decade from 1999 to 2008 there were 32,173 deaths on Britain’s roads, (fortunately in the UK the numbers are falling, from 3,423 in 1999 to 2,538 in 2008).  Since the UK population is around 60 million people and the worldwide population is around 4 billion then one can calculate an approximate number for the global total of road deaths for the decade, say around 1 million people (allowing for a lower percentage of vehicle ownership in poorer countries) or 100,000/yr. Yet we accept the risks of travelling by road every day, whilst nuclear power is considered by many to be too dangerous to be allowed to continue.

What is the reason for the difference in the perception of these risks?
In order to compare risks you consider the probability of an event occurring, within a specified period of time, multiplied by an assessment of the consequences.  These might be measured in many ways from the financial to the human costs.  Clearly the damage that could be caused by a single nuclear incident, such as a major release of radioactive material, is potentially of a very high magnitude but this has to be considered against its probability.

If, for example, a nuclear accident had a world wide probability over a 63 year period of 6/63 of occurring in any one year and the consequences of such an accident were say 50,000 deaths, then each year there would be a potential for 50,000*6/63=4,761 fatalities/yr worldwide or, in other words, not quite double the total number of road deaths per year in the UK alone.  

The consequences of a single serious road accident would, however, be limited to a relatively small number of casualties.  This is the reason why many people are scared of nuclear power.  Although the probability of a serious event is relatively low, a single nuclear incident is capable of devastating the lives of hundreds of thousands of people in one event, either by turning them into refugees or making them live under the shadow of a radiation induced illness. Whilst we are all accustomed to, and accept, the steady heavy casualty rate on the world’s roads, the latter is less frightening and rarely hits the headlines.

What is the Risk of a Nuclear War?
Vertical scale is no of warheads
If you want to consider another scenario which has very serious consequences, what about a nuclear war!  Several countries like North Korea or Pakistan, with recent histories of conflict or politically instability, have nuclear weapons and others, like Iran, are seeking to make them. The devastating consequences of a nuclear conflict would be fully global and could reduce human life on this planet to a fraction of its current population. The graph shows the number of nuclear warheads held by the US and the USSR/Russia against time. I think it is very scary but the vigorous political campaigns for nuclear disarmament of the sixties don't seem to be very active today!

Forgo Nuclear Power and add to Global Warming?
Of course if nuclear power generation (which has the major benefit of being carbon neutral and therefore doesn't add to global warming) is abandoned, most of the generating capacity must be replaced. Is it possible to develop renewable sources and reduce consumption to replace the 30% or so of electricity generated by nuclear power in Germany?  Although Germany has announced aggressive targets for increasing the percentage of renewable energy, from 17% in 2010 to 35% in 2020 if these are not acheived the power currently generated from nuclear sources will be replaced by some renewable energy, by importing power from France, which generates 83% of its electricity from nuclear power, by importing more gas from Russia and by augmenting generation from coal burning power stations.

In other words, unless you can afford to invest very heavily in renewable energy production, and everyone accepts its associated inconveniences, closing nuclear power stations is likely to add to the carbon footprint of Europe and increase the inevitability of global warming! Now there’s a scenario with very serious irreversible consequences and an almost guaranteed probability, (although there are still people who don't believe it).  We already know that the north polar ice cap is shrinking and that glaciers are melting at a very high rate in Greenland, so the only question is when will the results be felt in mainland Europe!

How do you balance this risk and its consequences against those of a potential nuclear accident?  I hope that the politicians responsible for these difficult decisons are capable of thinking further than the next election and that they don't follow their instincts to chase the votes by taking the easy way out!

Fortunately other options exist even though, at the moment, they are not being actively pursued by western nations!


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