Alarmist coverage of the latest attempt to contain radioactive contamination at Fukushima Daiichi distracts from the fact that the nuclear incident was never more than a sideshow to the true scale of the tsunami tragedy
It’s been almost two and a half years since the Tohoku earthquake, which triggered the tsunami that swept across Japan, causing massive loss of life and destroying towns and villages. The best-known, but perhaps least serious, consequence of the tsunami is back in the news: the continuing efforts to contain radioactivity from the nuclear reactor meltdowns at the Fukushima Daiichi power station.
Some readers might be wondering how I could describe what’s officially the worst nuclear accident since Chernobyl as the least serious consequence of the tsunami. I’m not implying that the incident wasn’t serious. But the way it was — and continues to be — covered is out of all proportion. Over 18,500 people lost their lives as a result of the tsunami. Of those, the number attributable to Fukushima is zero, despite the meltdowns continually being described as ‘deadly’ and radiation levels as ‘lethal’. It all adds to the continuing demonisation of nuclear power, which is — to say the least — unhelpful.
The latest developments concern the containment of water which has been used to cool the molten remains of the plant’s affected reactors. This is being stored in tanks by Tokyo Electric Power (TEPCO), which maintains the plant. Some of these tanks have been discovered to be leaking, leading to radioactive elements reaching the ocean. The latest attempt to contain these leaks, led by the Japanese government rather than TEPCO, is a proposal to create a ‘freeze-wall’ by burying coolant pipes in the soil surrounding the plant to a depth of around 30m, then pumping in salted water at -40°C to freeze the groundwater. This effectively creates a permafrost zone which, the engineers claim, will be able to stop contaminated water from leaking out of the protected zone, and equally stop clean water from leaching in and becoming contaminated.
Despite breathless coverage descibing this as a ‘desperate attempt’ and a ‘crazy plan’ this is actually a well-established technique, used to stabilise loose ground for excavations, for example. It’s been used in London (on the excavation of the new Jubilee Line stations) and at CERN, in the construction of the huge caverns that house the Large Hadron Collider’s detectors. It also has a pedigree in the nuclear sector: it’s used in uranium mining, and has been used to contain nuclear waste at the Oak Ridge National Laboratory in the US. Ice is an effective radiation shield against alpha and beta radiation, and it’s the latter which is believed to be the major problem with the Fukushima water.
It’s certainly ambitious — the Fukushima freeze wall will be the largest ever created, and will have to last for much longer than they are generally used for — and expensive, because the coolant needs to keep flowing to keep the ground frozen; costs are estimated at over £300m, which includes equipment to remove contaminants from the water. But ‘desperate’? ‘Crazy’? Hardly.
As Neil Hyatt, professor of nuclear waste management at Sheffield University points out, the major challenge at Fukushima is to decontaminate the water by removing the radioactive isotopes and stabilising them into a form suitable for long-term storage and disposal — there is significant expertise in this in the UK, based around vitrification techniques developed at Sellafield. The ice-wall will have to be thoroughly tested to minimise porosity; it’s unlikely to be a completely impervious barrier, but should be able to keep the flow of isotopes down to a level which will not lead to dangerous radiation dosages.
As for the effect on the nuclear sector outside Japan, the lessons seem to be the same ones drawn from the Fukushima incident itself. Ensure that regulators are not too close to the companies maintaining and operating nuclear facilities; use the best possible techniques for containing radioactivity (if TEPCO’s storage tanks had been welded, rather than riveted and sealed with rubber, it’s likely that the leaks would have been much less severe, or might not have occurred at all). Overall, it’s a salutory lesson in planning for the worst, because if you don’t, it’ll cost you more to clean up the mess than it would have cost to put the safeguards in originally.
But it shouldn’t be an argument against the deployment of nuclear. Once again, the reactors at Fukushima Daiichi were old, scheduled for shutdown; their newer neighbours at Fukushima Daiini worked perfectly. The nuclear incident was never more than a sideshow to the natural disaster of the tsunami. It was a tragedy of the intersection of human settlements and plate tectonics, not of the nuclear industry.