The Japanese operator of a stricken nuclear plant said Saturday it has started dumping a mineral into the sea that absorbs radioactive substances, aiming to slow down contamination of the ocean.

Tokyo Electric Power Co. (TEPCO) said it had begun dropping zeolite near a water outlet from the Fukushima Daiichi plant -- which has been leaking radiation since it was crippled by a March 11 quake and tsunami -- from Friday.

The mineral has wide-ranging industrial applications, including nuclear waste processing.

Officials hope it will help to reduce the spread of radioactive materials from the plant into the Pacific, though the effectiveness of the measure was not yet clear.

The mineral has been used to help mitigate other nuclear accidents, including the 1979 Three Mile Island nuclear accident in the United States.

Officials from 50 nations to meet for Chernobyl anniversary
Kiev (AFP) April 16, 2011 - Officials from some 50 countries are due in the Ukrainian capital Kiev on Tuesday for events ahead of the 25th anniversary of the Chernobyl nuclear disaster, organisers said.

"Representatives of some 50 countries, including presidents and prime ministers, will participate in the events" on April 19, a week before the April 26 anniversary of the disaster, Ukrainian foreign ministry spokesman Oleg Voloshyn told AFP.

Among those taking part will be European Commission President Jose Manuel Barroso, who will open a summit on civilian nuclear use, and French Prime Minister Francois Fillon, who will be among those leading efforts to raise 740 million euros ($1.06 billion) to help pay for the construction of a new concrete shelter over the ruins of the Chernobyl site.

Organisers said Russian Prime Minister Vladimir Putin and Kazakh President Nursultan Nazarbayev are also expected to take part.

April 26 will mark 25 years since the fourth reactor at a nuclear power station in the Ukrainian city of Chernobyl exploded, contaminating a swathe of Europe, with Ukraine, Belarus and Russia the worst affected.

The anniversary comes amid global concern over nuclear power after the Fukushima Daiichi plant in Japan's northeast was crippled by the devastating March 11 earthquake and tsunami.