Radiation threat uncertain as blasts rock Fukushima reactors

There was a hydrogen explosion on Saturday morning at reactor 1, followed by a similar blast at reactor 3 this morning and the extent of radiation exposure to the surrounding area it is not currently known.

The problems seems to have been caused by the tsunami, rather than the earthquake per se, which damaged the plant’s back-up diesel generators that pump water into the reactor to cool it after automatic shut down.

The Engineer will be covering the situation, but for a breakdown of how reactors are engineered to deal with seismic shaking see Friday’s coverage of the event.