Japan has stopped the flow of radioactive water from the No. 2 reactor at the Fukushima Daiichi nuclear plant into the Pacific Ocean. Now on to the next crisis: The plant’s operator, Tokyo Electric Power Co., is now considering injecting nitrogen gas into the No. 1 reactor to prevent a hydrogen explosion. The New York Times reports on a confidential assessment from the Nuclear Regulatory Commission, which predicts several more problems at Fukushima Daiichi: growing stress on containment vessels as they fill with radioactive water; possible explosions due to the release of hydrogen and oxygen gas from seawater within the reactors; and blockages due to semi-molten rods and salt buildup in the reactors.