Japanese officials desperate to contain an ever-growing crisis at the Fukushima nuclear power station are looking to use artificial permafrost to stop radioactive water from leaking. The idea is to build a mile-long wall of frozen earth around Fukushima’s toxic reactor buildings to stem the groundwater contamination; the most experienced specialists in the field say the plan should work.

The Japanese firms involved appear to be taking a go-it-alone approach. Two weeks ago, a top official at Tokyo Electric Power (Tepco) signaled that the utility behind the Fukushima disaster would seek international assistance with the Fukushima water contamination crisis.