Russia repeated an offer first made two years ago to help Japan clean up its radiation-ravaged Fukushima No. 1 nuclear station, welcoming Tokyo Electric Power Co.'s decision to seek outside help.

As Tepco pumps thousands of tons of water through the wrecked Fukushima station to cool the melted cores of three reactors, the tainted runoff was found to be leaking into groundwater and the ocean. The approach to cooling and scrapping the plant will need to change and include technologies developed outside Japan if the cleanup is to succeed, said Vladimir Asmolov, first deputy director general of Rosenergoatom, Russia's state-owned nuclear utility.

"In our globalized nuclear industry, we don't have national accidents, they are all international," Asmolov said. Since the Liberal Democratic Party took power in December and Shinzo Abe became the prime minister, talks on bilateral cooperation on the Fukushima cleanup have turned "positive" and Russia is ready to offer its assistance, he said from Moscow last week.