Highly radioactive water from Japan’s crippled Fukushima nuclear plant is pouring out at a rate of 300 tonnes a day, officials said on Wednesday, as Prime Minister Shinzo Abe ordered the government to step in and help in the clean-up. The admission indicates that two and a half years after the plant was hit by a huge earthquake and tsunami, plant operator Tokyo Electric Power Co (Tepco), which only recently admitted water had leaked at all, has yet come to grips with the worst nuclear disaster since Chernobyl. Calling water containment at the Fukushima Daiichi station an “urgent issue”, Abe ordered the government for the first time to get involved to help struggling Tepco handle the crisis. The newly acknowledged leak from the plant 220 km northeast of Tokyo is enough to fill an Olympic swimming pool in barely a week. The water is spilling into the Pacific Ocean, but it was not immediately clear how much of a threat it poses. In the early weeks of the disaster, the Japanese government allowed Tepco to dump tens of thousands of tonnes of contaminated water into the Pacific in an emergency move. But the escalation of the long-running crisis raises the risk of an even longer and more expensive clean-up, which is already forecast to take more than 40 years and cost $11 billion. The admission also further dents the credibility of Tepco, which has been severely criticised for its failure to prepare for the massive 2011 tsunami and earthquake that devastated the plant, for a confused response to the disaster and for covering up shortcomings. “We think that the volume of water (leaking into the Pacific) is about 300 tonnes a day,” said Yushi Yoneyama, an official with the minister of economy, trade and industry, which regulates Tepco.