The pervasive fear of nuclear radiation leaks is misguided, argues Joseph Mariathasan

UK prime minister Theresa May’s decision to delay a final decision on the Hinkley Point nuclear power station is another stumbling block for nuclear power. Yet it can be argued nuclear power represents an invaluable source of energy that has been misrepresented in the public perception.

The Fukushima Daiichi radiation disaster in March 2011 epitomised the problems countries face in their attitudes to nuclear energy. The disaster led to all nuclear plants in Japan being shut down and 100,000 people being evacuated. There was worldwide news coverage and huge blame placed on the operator, TEPCO. Other nations such as Germany panicked and shut down their nuclear power plants, despite the absence of any problems. Subsequent German policy became to cease the use of nuclear energies.

Yet, despite the considerable escape of radiation, ranked in the most serious category in the Fukushima Daiichi radiation disaster, there has not been a single death, nor even a single health casualty, attributable to the leak. This, as Oxford professor Wade Allison argues in his book, “Nuclear is for life – a cultural revolution”, calls for an explanation.

The key message is that society’s attitudes to acceptable levels of radiation are massively out of kilter with the actual reality of the risks and the behaviour of radiation damage on living things. Allison’s argument is that the current approach to the impact of radiation on life is based on a fallacy. This is the idea that the damage caused is a linear function of the exposure – if you double the exposure, the damage is doubled. Clearly, when exposures are large enough, people and animals die of radiation sickness. But what if the exposure is millions of times smaller, close to background levels of radiation or less?

The current approach is the Linear No-Threshold (LNT) model of the relationship between radiation exposure and damage to health, which says a low dosage will cause commensurately less damage but still some damage. Allison argues this fallacy arose through the impact of Hermann Muller, an American geneticist. His work on the impact of X-rays on fruit flies led to the LNT model. But his lowest dose was 4,000 mGy – a dose high enough to have killed fire-fighters at Chernobyl. Other work has shown that the LNT model does not fit low-dose data for fruit flies.

The LNT model leads to the conclusion that if millions of people are exposed to radiation, no matter how low a level, there is an expectation there will be a certain number of deaths arising directly from the radiation exposure, and the number will be a function of the dose. Current approaches to nuclear safety are based on the LNT model. This leads to the objective of ensuring radiation is As Low as Reasonably Achievable (ALARA).

The adoption of the LNT and ALARA as the guiding principles of safety means radiation levels are set within a small fraction of naturally occurring levels. This is unrelated to any risk but comes from a political wish to say that the effects of radiation have been minimised. Allison argues that this analysis is fundamentally wrong because it misunderstands the impact of radiation on living things.

Life, as Allison argues, evolved in the presence of radiation, and the framework of living things reflects the necessity throughout the evolution of life to be able to deal with low levels of radiation. The impact on life comes in two stages. The first is that radiation impacts the atoms and molecules of which living tissue is made. This damage is linearly proportional to the amount of radiation energy absorbed.

The second stage is how that tissue responds to the trail of broken molecules if it is still alive. This is not at all linear. At high levels, it can destroy the ability of a cell to service itself, called cell death. If too many cells are killed, the entire organism may be at risk from Acute Radiation Syndrome (ARS). At low levels of radiation damage, most cells with damaged DNA are either repaired correctly by enzymes within hours or repaired with errors, such that they are no longer viable and fail to be reproduced.

ARS can be fatal within a few weeks. Otherwise, recovery is complete usually, once the cell cycle has been re-established. However, a few of those that suffer double strand breaks (DSBs) are incorrectly repaired and survive. These mutations may persist in abnormal chromosomes, whose behaviour is kept in check by the immune system. It is predominantly the failure of the immune system that gives rise to cancer. The process is the same whether the error was initiated by radiation or another source of chemical oxidation.

It is difficult to argue with Allison’s assertion that the treatment of radiation exposure has become confused as a result of political and historical events overwhelming the actual scientific evidence. There have been no deaths arising from radiation exposures in the Fukushima disaster, and, Allison argues, none is ever likely to arise. The public fear over anything relating to radiation levels has become so ingrained that a massive educational effort is required to change attitudes. In 2005, the French Academy of Medicine set out a full academic case for a complete change in the regulation of radiation[1]. That has still to be acted on.

If climate change arising from the burning of fossil fuels is the existential threat facing mankind, then ignoring the one source of power that can actually supply all of mankind’s energy needs out of misplaced fears would be the height of folly. You may not agree with Allison’s assertion that, even if there were another accident at a nuclear power plant, there would be no human radiation disaster. But that debate still needs to be conducted.

Joseph Mariathasan is a contributing editor at IPE

[1] 2005: Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionising radiation. French National Academy of Medicine