The Los Angeles Times reported in the last half hour:
High radiation levels at the Fukushima Daiichi power plant have forced workers to abandon at least temporarily their desperate efforts to spray water from helicopters and water cannons in a last-ditch effort to cool the plants and stave off a meltdown.
The Times also reported that efforts to cool down the reactors and spent fuel pools have had little effect:
Helicopters supplied by Japan’s military dumped only four loads of seawater, totaling about 30 tons, on the plant, before abandoning the effort Thursday morning, although officials said they would resume efforts when possible. Most of the water missed the reactors.
And the Times had a discouraging update on efforts to rig an electrical transmission line to the crippled plant:
In another disappointment, officials of Tokyo Electric Power Co., which owns the plant, said that a new power line being strung to the plant from the country’s electric grid would not be completed until Friday at the earliest. Officials had originally hoped to start connecting the new line Thursday afternoon.
It gets worse:
The helicopters also took new pictures of the spent fuel pools on the roofs of the reactor buildings and have apparently confirmed fears that the pool at reactor No. 4 has boiled dry.
The Times explained the significance of this:
The spent fuel pool is a particular source of concern because it contains at least 135 tons of fuel rods, more than is in any of the reactors. Moreover, the fuel rods are not inside a containment vessel. If they start burning, the ash will be released directly into the environment.