18:10 JST March 20: The operator of Japan’s overheating, leaking nuclear plant backed off a tricky venting of radioactive gas from a troubled reactor Sunday as concerns grew about wider contamination of food and water.
After the cascading troubles at the Fukushima plant appeared to lessen Saturday, pressure inside the vessel holding the reactor of Unit 3 rose again Sunday, dealing a setback to the government and forcing officials to consider the dangerous venting. Nuclear safety officials said one of the options could release a cloud dense with iodine as well as the radioactive elements krypton and xenon.
The plant’s operator, Tokyo Electric Power Co., temporarily suspended the plans Sunday after the pressure inside the reactor stopped climbing, though it was at a relatively high level.
"It has stabilized," Tokyo Electric manager Hikaru Kuroda told reporters. Kuroda said temperatures inside the reactor reached 572 Fahrenheit (300 degrees Centrigrade) and the option to release the highly radioactive gas inside – a maneuver he called a "dry vent" – is still under consideration if pressure rises.
The higher reactor pressure may have been caused by a tactic meant to reduce temperatures – the pumping of seawater into the vessel, Kuroda said.
Using seawater to douse Unit 3 and the plant’s five other reactor vessels or their nuclear fuel storage pools was a desperate measure since it’s corrosive, damaging the finely milled machine parts. The government acknowledged Sunday that the entire complex would be scrapped once the emergency is resolved.
"It is obviously clear that Fukushima Dai-ichi in no way will be in a condition to be restarted," Chief Cabinet Secretary Yukio Edano told reporters.