The Nuclear Regulatory Commission is warning that nuclear plants in the central and eastern United States face previously unforeseen threats from major earthquakes. The NRC says it has ordered new seismic tests to see if all 96 reactors in eastern and central states can withstand the earth movements predicted under a government model. Critics of the nuclear industry says the tests will only delay the upgrades needed to withstand earthquakes. The news comes as the operators of Japan’s earthquake-stricken Fukushima nuclear plant say they have contained a new radioactive leak of eight tonnes of water inside one of their reactors.