Workers work on the construction of an iIn fading light and just a stone’s throw from the most terrifying scenes during Japan’s worst nuclear accident, engineers resumed their race against time to defeat the next big threat: thousands of tonnes of irradiated water. If all goes to plan, by next March Fukushima Daiichi’s four damaged reactors will be surrounded by an underground frozen wall that will be a barrier between highly toxic water used to cool melted fuel inside reactor basements and clean groundwater flowing in from surrounding hills. Up to 400 tonnes of groundwater that flows into the basements each day must be pumped out, stored and treated – and on-site storage is edging closer to capacity. Decommissioning the plant will be impossible until its operator, Tokyo Electric Power [Tepco] addresses the water crisis. Last month workers from Tepco and the construction firm Kajima Corp began inserting 1,550 pipes 33 metres vertically into the ground to form a rectangular cordon around the reactors. Coolant set at -30C will be fed into the pipes, eventually freezing the surrounding earth to create an impermeable barrier. More