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Fukushima fallout: Reader riposte



13 April 2011 14:55

Richard Broinowski writes:

In her comment on my riposte to George Monbiot, Martine Letts disputes both my view about the severity of radiation sustained by Japanese workers at Fukushima and inhabitants in surrounding prefectures, and indeed the severity of the damage to the reactors themselves.

On the first, it is pointless to argue the toss about who received what doses and how it will affect them. This is way too premature. The crisis is far from over. An increasing number of workers, many unskilled, are being sought to work in the highly radioactive environment of the Fukushima plant. Efforts to cool the reactors and spent fuel and reduce the dangers of further radioactive releases will need to be intense over many months. Decommissioning the damaged facilities will take years.

What we do know is that the Japanese authorities, both in TEPCO and government, have attempted to put the most favourable gloss on what took place to prevent panic, and have produced wildly conflicting estimates of radiation release, many very low. But an independent Austrian monitoring body has claimed that in their panic the Japanese missed the venting in the first three days of the crisis of substantial quantities of Iodine 131 (estimated at 20% of what vented at Chernobyl) and Cesium 137 (20-60% of the amount released at Chernobyl).

Meanwhile the US Nuclear Regulatory Commission (NRC), which is closely monitoring events at Fukushima, recommended an exclusion zone of 80 kilometres, much wider than the 20 kilometres recommended by Japanese authorities. A wider evacuation zone has been vindicated by radiation measurements at various sites outside the 20km zone, such as the village of Iitate, 43 km from the plant, where measured levels of radioactivity have been comparable to those in mandatory evacuation zones around Chernobyl.

As for the potential damage to the reactors and spent fuel, Martine makes the surprising assertion that the accident at Chernobyl was 'much more serious than Fukushima could ever have been'. Fukushima is not yet over, and we won’t know for a long time how serious it really is. What we do know is that the cores of three reactors have already suffered partial melt-downs, and so have the considerably greater number of irradiated spent fuel rods in the storage pool in a fourth.

A British scientist, John Large, suggests that it was actually a fission event that occurred in that pool. Reactor number three is also fuelled with MOX, which contains much more Plutonium than in conventionally-fuelled light-water reactors, and emits greater volumes of long-lasting carcinogenic ionising radiation.

The Fukushima plant has around 1760 tonnes of in-use and spent reactor fuel; the Chernobyl No.4 reactor which exploded had 180 tonnes. The NRC's most recent confidential assessment is reported in the New York Times (5 April) to express concern about a wide array of new threats at the site that could persist indefinitely.

These include risk of rupture of already damaged, water-laden containment structures with ongoing aftershocks; and explosions within the same structures, made more likely by the extensive damage to fuel elements impairing cooling.  

I suggest that rather than focus on the psychological fears people suffer from the illusory effects of radiation as Martine suggests, we should stop trying to minimise both the extent of damage at Fukushima and the short and long term carcinogenic and mutagenic damage that has already been caused, and that will continue well into the future.