3D diagram of the Fukushima Daiichi nuclear plant locating stricken reactors and key facilities with timeline of events. [Photo/Agencies]

What is the current risk of radiation-related health problems in Japan to those near the reactor at the time, and those in other parts of Japan?

The actions proposed by the Government of Japan are in line with the existing recommendations based on public health expertise.

The Japanese government is asking people living within 20 km of the Fukushima Daiichi nuclear power plant to evacuate and those between 20 km and 30 km away from the plant are asked to stay indoors in unventilated rooms. People living farther away are at lower risk than those who live nearby.

This assessment can change if there are further incidents at these plants. However, radiation-related health consequences will depend on exposure. Exposure in turn is dependent on the amount of radiation released from the reactor, weather conditions such as wind and rain at the time of the explosion, the distance someone is from the plant, and the amount of time someone is in irradiated areas.