As radiation continues to spread from the crippled Fukushima Daiichi nuclear plant, Japanese and US officials are considering novel measures to try to corral the contamination.
Skip to next paragraphSticky resin may help. On Thursday, Tokyo Electric Power (TEPCO) plans to test it, spraying this adhesive substance on an area of ground near the plant, said Japanese nuclear safety authorities on Wednesday. The idea is to glue down any fallen radioactive particles.
A giant tarp has also been proposed. Japanese Chief Cabinet Secretary Yukio Edano said nuclear experts might cover reactor buildings with a special material to try and stop emission of radioactive substances.
The US is readying a shipment of radiation-hardened robots to help the Japanese fight this problem, said Peter Lyons, acting assistant secretary of the US Department of Energy.
"We're moving expeditiously to ship not only the robots but also operators who [would] train Japanese operators," Dr. Lyons told a Senate committee on Tuesday.
That officials are considering such unusual approaches reflects the fact that, despite some progress in restoring electricity to the Fukushima complex, the nuclear crisis has no end in sight.
"We are not in a situation where we can say we will have this under control by a certain period," Mr. Edano told reporters at a Wednesday news briefing.
Highly radioactive water leak
The recent discovery of highly radioactive water in maintenance tunnels and reactor basements has quashed optimism in Japan that TEPCO might be on the verge of winning its nuclear battle.
On Wednesday, Japanese nuclear safety officials said that a sample of seawater taken some 300 yards from a plant wastewater outlet contained over 3,000 times the legal limit of radioactive iodine.
That suggests that the radioactive water found previously is now making its way into the ocean.
US officials believe that the radioactive water was an inevitable side effect of Japan's "feed and bleed" approach to cooling Fukushima nuclear reactors.
This method has involved pouring hundreds of tons of water onto the reactors via fire hoses and helicopter drops, in an attempt to prevent nuclear fuel rods from melting down.
This water is leaking out and finding its way into structures and soil near the reactor units.
"The exact flow path of that leakage has not been determined, but it's a result of the water that they've been injecting since shortly after the onset of the event," said Bill Borchardt, executive director for operations at the US Nuclear Regulatory Commission (NRC), at Tuesday's Senate hearing.
Possible reactor damage
The NRC believes that Fukushima Daiichi reactor units 1, 2, and 3 have experienced partial fuel damage due to overheating. Ominously, units 2 and 3 appear to have "some primary containment damage," said Mr. Borchardt.
In other words, they have been breached in some way and are leaking radioactivity.
Meanwhile, TEPCO chairman Tsunehisa Katsumata apologized for the trouble and anxiety cause by the Fukushima radiation leaks. He spoke to reporters on Wednesday in place of TEPCO's president, Masataka Shimizu, who has been hospitalized for stress-related health problems.
• AP material was used in this report.
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