Tepco, the company which runs the Fukushima plant, has evacuated 800 of its personnel. The move illustrates how life-threatening work at the plant has become. Fires and explosions have resulted in 15 workers being injured. Far more hazardous, though, are the high levels of radiation.
**Heroes**
The permissible level of exposure to radioactivity is 50 Sv per year. Wim Turkenburg from Utrecht University says that the radiation levels are far higher now the plant has been damaged and radioactive material has escaped. Would he describe the remaining staff as heroes?
*“I understand the radiation level to be high, around 400 Sv per hour, while workers are only allowed to be exposed to 50 Sv per year… So all the people that are still there have been exposed to extremely high radiation and will develop all sorts of illnesses associated with radioactivity. You can certainly call them heroes.”*
Folkert Draaisma of the Nuclear Research and Consultancy Group (NRG) based in Petten, north of Amsterdam, qualifies the hero status somewhat. He doesn’t believe people’s lives are being recklessly put at risk. *“You can’t talk about people being sacrificed here. That was indeed the case at Chernobyl, where people were sent onto the roof without planning or protection. Of the 245 workers who were exposed to over 1,000 Sv, 28 have since died.”*
**Lead barriers**
Even at Fukushima, not all the work can be done from the safety of monitoring rooms. After the fire in reactor 4 was brought under control, the next job was to cool the uranium in the reactors using techniques such as pumping seawater inside the buildings. The special clothing worn by workers offers little protection. They could, in the event of high radiation levels, work behind lead barriers which absorb the radioactivity. The protective clothing also has a meter to measure the radiation. *“After being exposed to more than 400 Sv, a worker is pulled out,”* explains Mr Draaisma.
The latest weather forecasts indicate that the radioactive material is being blown out to sea. The radiation levels are also reported to differ from one place to another in the vicinity of the plant. Despite these facts, it is impossible to gauge the precise risks run by staff who have remained at Fukushima. But Mr Turkenburg says it is crucial that they do remain because, if the reactor is left unmanned, the situation could get worse.
*“There would be cooling problems again and nothing could be done. The reactor would dry out again and the whole thing would melt. Then, even larger amounts of radioactivity would escape into the local area and would be spread over larger areas by the wind.”*
**Radiation sickness**
Three Fukushima workers have already been hospitalised with radiation-linked symptoms. *“After really high levels of radiation, you can become ill with radiation sickness [acute radiation syndrome],”* says Mr Draaisma. *“The radiation affects the gastrointestinal tract.”* Exposure to very high amounts of radioactivity (around 10,000 Sv) can prove fatal in a short period of time, while 100 Sv per year can be carcinogenic.
