Among the many problems plaguing the cleanup at Fukushima is the threat of radioactive water spilling from the site. The Japanese government is now ramping up its efforts to contain this problem, by flicking the switch on an underground ice wall that will enclose the failed nuclear facility to slow the spread of contaminated material.
An ice wall might sound like something out of science fiction, but is actually an engineering technique that has been used for tunnel boring and mining, albeit on a smaller scale. Refrigerated brine cooled to -30 degrees Celsius (-22 ° F) will be pumped through pipes plunging 30 m (98.5 ft) into the ground, freezing the soil and eventually sealing the four reactors damaged in the 2011 earthquake and tsunami inside a 1,500 m (5,000 ft) barrier.
Scientists have recently detected elevated levels of radiation in seawater samples collected near the reactors, and even as far away as the US west coast, confirming that there is an ongoing release of toxic materials from the plant. Workers at Fukushima have already filled purpose-built steel tanks with tons of toxic water from the reactors, but there are some areas that they simply can’t access as radiation levels remain dangerously high, so high in fact that even robots sent in to investigate are having their wiring fried.
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