Japan earthquake: the nuclear crisis is not over yet
Japan says disaster has been averted at the Fukushima nuclear plant but serious questions remain
The Japanese authorities have told the International Atomic Energy Agency (IAEA) that the levels of radioactivity outside the Unit 1 reactor at the Fukushima Daiichi power plant are falling and that there was no rupture in the unit’s containment vessel that would have led to a large-scale release of radiation. However, it now appears that the cooling systems in the No 3 reactor have also failed.
Sea water and boron are being pumped into the Unit 1 vessel with the aim of preventing a meltdown of the fuel inside. For the time being, the threat of a meltdown has receded. It is not immediately clear if the same is going to be done at the No 3 reactor.
It is the first time such desperate measures have been employed. Olli Heinonen, the former head of the IAEA’s safeguards department now at Harvard University, told me that the seawater has to be continually pumped out of the vessel as well as being pumped in, and he has so far seen no confirmation that the temperature of the water is stable or dropping.
Heinonen said that the equipment being used to do the pumping has necessarily been improvised, and will be therefore be highly vulnerable to aftershocks.
He also pointed out that there has been no word so far on the spent fuel at the site which would be kept in pools at the reactor. Any breakdown in the cooling system could cause the spent fuel to melt, with the risk of a significant release of radioactivity.
There is widespread uneasiness despite the reassuring noises coming from the authorities over the situation, in part because of the industry’s history of ignoring warnings and covering up safety problems.