Operators of the Fukushima nuclear plant say the level of highly radioactive water has dropped slightly, a day after they began removing water from one of the reactor buildings.
About 200 tonnes of water in a tunnel have been pumped out. Tens of thousands of tonnes of radioactive water have accumulated, hampering efforts to restore cooling systems.
French specialists have been studying the plant at close hand. The reactor maker Areva is stepping up its role by providing equipment to clean up the water.
Chief Executive Anne Lauvergeon said plant operators TEPCO hoped for the water treatment to start before the end of May.
“If we manage to bring this about as soon as possible, it will effectively be a world record at that speed,” she told a news conference.
Chemicals will be injected into the contaminated water, causing radioactive substances to separate and fall to the bottom.
Large quantities of water were used to prevent meltdown after the tsunami.
The operators hope to stabilise the plant over the next nine months.