7 Août 2014
04.08.2014_No245 / News in Brief
4 Aug (NucNet): Almost 16,000 cubic metres of clean groundwater has been discharged into the Pacific Ocean near the Fukushima-Daiichi nuclear power station since operations began to reduce the accumulation of contaminated water by diverting uncontaminated groundwater around the reactor buildings, the Japan Atomic Industrial Forum said.
Since the discharge operation began on 21 May 2014, station operator Tokyo Electric Power Company (Tepco) has discharged groundwater 11 times, representing a total volume of 15,828 cubic meters, a statement said.
Tepco said “some time” would be needed to fully determine the effectiveness of the operation and that it would continue monitoring the situation. It said measurements at various observation wells showed levels of groundwater had dropped by about 10 centimetres.
Tepco began discharging groundwater into the Pacific Ocean after it installed a groundwater bypass system, which diverts the flow of naturally occurring groundwater between the hilltop behind Fukushima-Daiichi and the reactor buildings, which are close to the ocean.
The groundwater bypass system intercepts clean groundwater as it flows downhill toward the ocean, and reroutes it safely around the facility. The water is temporarily stored to verify its quality before it is released into the ocean.
The groundwater bypass system is one of several strategies being used to reduce the accumulation of contaminated water at the station. The aim is to substantially reduce the amount of groundwater flowing into the reactor building basements.
Another strategy is the construction of impervious underground “ice walls” in the grounds of the facility to try to slow the build-up of radioactive water.
The walls are being built by drilling shafts and inserting freezer pipes designed to freeze soil and prevent the flow of groundwater through the soil. Jaif said in a statement today that work on the walls is progressing, but they are not yet fully frozen and Tepco is looking at “additional measures” including adding dry ice to the shafts.
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