Japanese nuclear officials say radiation levels inside a nuclear power plant have surged to 1,000 times their normal levels after the cooling system failed.
The nuclear safety agency said early Saturday that some radiation has also seeped outside the plant, prompting calls for further evacuations of the area. Some 3,000 people have already been urged to leave their homes, as the government declared its first-ever state of emergency at a nuclear plant.
The cooling system for a reactor at the Fukushima Daiichi power plant failed on Friday after a massive earthquake caused a power outage.
The continued loss of electricity has also delayed the planned release of vapor from inside the reactor to ease pressure. Japan's nuclear safety agency said pressure inside one of six boiling water reactors at the Fukushima Daiichi plant had risen to 1.5 times the level considered normal. Hours after the evacuation order, the government announced that the plant in northeastern Japan will release slightly radioactive vapor from the unit to lower the pressure in an effort to protect it from a possible meltdown.
Bottom line: There may be not one but two units at risk. They’re both on last-ditch, fail-safe systems that rely on limited-life batteries to keep cooling water flowing and covering the core. The operators are in a race against time to replace them or to get electric power either from repaired or replaced back-up generators or restored access to the grid. We don’t know the status of any of these efforts.
Without continuously circulating cooling water, the still very hot reactor core will slowly (over hours) boil away the remaining cooling water, and that could eventually leave the reactor core and its radioactive fuel rods uncovered. We don’t know how far along we are in that sequence. What happens after that can lead to an uncontrolled meltdown and releases of radiation.
“Controlled” radiation releases, through filters (we don’t know their effectiveness), have already been used to relieve pressure inside the reactor. [There's a report they've lost any other ability to control pressure.] suspect most has been contained inside a massive containment structure, which is designed to withstand everything except the things they didn’t plan for, like the loss of everything. We’re there.
There have already been pressure buildups inside the reactor (or containment?) that exceed its design capacity. We don’t know what it’s real limits are, and we don’t know what damage the earthquake caused to its integrity.