Is nuclear the only way forward?

Irrespective of personal conviction in regards to the reality of Anthropogenic Global Warming it is unarguable that energy production and associated matters are major political, economic, social and environmental issues.

Two books that influenced me over the last year are Thorium, energy cheaper than coal by Robert Hargraves and Radiation and Reason, the Impact of Science on a Culture of Fear by Wade Allison. Both Hargraves and Allison are physicists, both are convinced that AGW constitutes a major threat to the world and both conclude that the major use of some form of nuclear energy is essential. However they emphasise different aspects of energy production as a consequence of their different specialisations.

Allison was originally a nuclear physicist but later moved into the medical applications of physics. He examines the ideas of risk, knowledge and confidence; the atomic nucleus and the fact that most nuclei are stable; and then moves to ionising radiation, its measurement and natural radiation.

In the central chapters 5, 6 and 7, he uses hard data from Hiroshima, Nagasaki and Chernobyl events and nuclear medicine to demonstrate inter alia that any radiation 'dose' below 100 millisieverts (mSv) is not injurious to humans, and that doses are not cumulative. The sample sizes are very large and the data have good accuracy; consequently his conclusions are convincing.

Knowledge of cell and DNA behaviour is used to explain the ways in which the humans (and other living things) have multiple defence mechanisms against damage, whether caused by chemical attack (oxidation) or by ionising radiation. That prevents low doses 'accumulating'.

The back cover of the book says, in part:

• 'A clear and positive scientific account of the effect of radiation on life that brings good news for the future of mankind'
• 'For more than half a century the view that radiation represents an extreme hazard has been accepted. This book challenges that view by facing the scientific questions "how dangerous is ionising radiation?" and "why are we so worried about radiation?"'
• 'The first question is answered in accessible language for the general reader and related directly to modern scientific evidence and understanding. Briefly radiation isabout a thousand times less hazardous than is suggested by current safety standards'. (My emphasis)

Allison bases all his work on measured quantities. Units used are defined and errors are small. All science should be like that. Robert Hargraves in Thorium energy cheaper than coal is an example of work that is numbers based. Not just what happens but also how much.

Hargraves is an expert on energy policy. His detailed knowledge is encyclopaedic and almost daunting; inevitably he approaches the energy issue differently from Allison. Allison's approach is biological/medical; Hargraves is concerned with methods of energy production and the costs of energy for each method.

In addition to concerns about AGW, Hargraves also worries about air pollution per se and rising population. He talks of 'an unsustainable world'. His basic thesis is that most countries cannot afford to stop using coal power stations and that they will not stop – unless a cheaper alternative is available; hence the title of the book. Furthermore he contends that birth rates will not drop until some level of prosperity is achieved. His graph of GDP per capita against number of children per woman for a large number of countries is entirely convincing.

Hargraves starts by dealing with 'energy and civilisation'. He argues that the availability of energy is strongly linked to historic rises in living standards. But he asserts that present levels of energy production, let alone further increases, are unsustainable using current methods. He examines every imaginable method of production and develops a cost for each of them in cents per kilowatt hour (the 'unit' that your electricity meter measures). Examples are:

• 'Energy cheaper than coal must be < 5.6 cents/kwh'.
• 'Electricity cheaper than natural gas must be < 4.8 cents/kWh'
• 'Electricity cheaper than that from wind must be < 18 cents/kWh'
• 'Energy cheaper than from solar must be < 24 cents/kWh'.

He then analyses storage systems. Most are of small capacity in comparison to grid demand and automatically raise the final price of the energy. He notes that hydro power opportunities are limited and that pumped storage requires two (large) reservoirs.

The Uranium isotope 235 is said to be 'fissile'. When a U235 nucleus is hit by a neutron it splits roughly in half, gives out enormous energy, and spits out a lot more neutrons which in turn hit other U235 nuclei and so on. Controlled, that 'chain reaction' provides useful heat; uncontrolled it gives a big bang. Thorium is not fissile, it is said to be 'fertile'. When a neutron hits a Thorium 232 nucleus it makes its eyes water but it only spits out one particle and then later another which transmutes it into a Uranium 233 atom – which is fissile and a form of chain reaction then starts producing energy. So it is breeding its own fuel. A small amount of Uranium is needed to kick start the process.

Hargraves argues strongly that the best bet for producing energy cheaper than coal is the Liquid Fluoride Thorium Reactor LFTR. There is nothing new in the idea; much research and construction of reactors went on in the 1950s and 1960s. A good example was the Oak Ridge Lab (USA) molten salt reactor experiment which operated successfully for 4 years up to 1969. Work on LFTRs and similar has taken place in many countries. 'Since 1996 India has operated its experimental Kamini 30kw reactor… and… India's national strategy is to produce 30% of its electricity from thorium by 2050'.

Hargraves claims that LFTR reactors have many advantages over 'normal' Pressurised Water Reactors PWRs. Examples are:

• It promises to be able to produce electricity cheaper than coal
• LFTR reactor 'cleans' itself of products that damage a PWR; for example Xenon, which affects efficiency, simply bubbles out.
• A PWR operates at 160 atmospheres, whereas a LFTR works at normal atmospheric pressure so LFTR is safer.
• LFTR operates at much higher temperatures, a fact that increases efficiency of electricity production.
• LFTR produces less than 1% of the radiotoxic wastes compared to PWR.
• LFTR does not produce material suitable for bomb manufacture, it is hence proliferation resistant. (Hargraves places a high priority on non-proliferation.)
• Thorium is effectively an inexhaustible resource.

In keeping with his aim of 'energy cheaper than coal', Hargraves discusses in some depth a number of reactors that are under consideration across the world. Two that interested me are: (a)Denatured Molten Salt Reactor DMSR also uses Thorium; it could be a cheap source and is 'likely to be the first molten salt reactor to reach the market', but it requires more U235 to keep it running than LFTR. (b)The Toshiba Westinghouse AP 1000 which is a PWR reactor but is far superior to older reactors due to over 50 years of experience and development.

China is moving rapidly down the nuclear road. It has 14 plants in operation and 25 under construction, with a capacity of 60GW rising to 200 GW by 2030. In comparison the Three Gorges hydropower project which displaced well over a million people generates 18GW. China is using best ideas from everywhere – AREVA (Europe), Toshiba/Westinghouse, Pebble Bed reactors based on German work and fast breeder reactors from Russia. Notably the country has set up and funded a project to develop Thorium LFTR reactors. Hargraves claims that then Premier Wen Jiabao says that China will accelerate …nuclear energy and 'put an end to blind expansion in industries such as solar energy and wind power'.

Both books see nuclear power as the best hope. Radiation and Reason demolishes the fashionable Linear No Threshold LNT theory; asserts that current maximum permitted radiation levels are far too low – with no gain in safety – and that raising them to levels based on the science of today not the1960s would drastically reduce the cost of nuclear power. Thorium: energy cheaper than coal, using rather different data, also derides LNT as a fallacy; and remarks that guidelines have 'needlessly displaced thousands of people from areas near Fukushima where radiation levels are well below the safe level of 100mSv/yr'. Hargraves contends that only a very cheap energy source can displace coal, and that his analysis demonstrates that the only possible source is nuclear.

Both books are important and thoroughly recommended. Radiation and Reason is perhaps the easier read because it mainly concentrates on one issue – that low radiation is not dangerous. Thorium energy cheaper than coal is arguably a harder read because of complexity, but open it anywhere and you will find fascinating information. Particularly interesting is Appendix B which is a 2005 Moir and Teller paper advocating an 'underground power plant based on molten salt technology'. Teller died before publication so this was his last hurrah.

Both authors emphasise that 'Safety is boring but Fear sells'. Such an unscientific reaction stands in the way of progress. It is to be hoped that these books will start a move towards an acceptance that there is very good news –nuclear power is by far the safest way to produce energy. In particular leaders of groups such as Greenpeace, Friends of the Earth, A.C.F should read them and alter their current anti nuclear power position. They would do well to harken to Barak Obama who in a statement on March 26^th 2012 lauded the 'astonishing benefits that nuclear technology has brought…' and that:

...and, of course, it's the energy – the clean energy – that helps cut the carbon pollution that contributes to climate change.'