Tokyo Electric Power Co. discovered more radioactive water leaking into the sea Wednesday at its Fukushima Daiichi nuclear plant and quickly cemented a nearby pit.
According to a TEPCO release, one of the workers tasked with filling tunnels connecting units at the plant saw water flowing into a pit near the intake canal of unit 3. The basements of reactor buildings at the plant were flooded with water bearing varying levels of radioactive contamination following a March 11 earthquake, tsunami and station blackout.
Previously, water seeping into the network of tunnels, pipes and pits connecting the units had leaked into the ocean from cracks in the passageways. Those leaks were eventually sealed, but on Wednesday a TEPCO spokesman said significant levels of cesium were found in water seeping into the storage pit outside unit 3. Radiation at the pit water’s surface was measured at 1.5 millisieverts per hour. Subsequent seawater samples taken adjacent to unit 3 contained radioactive contaminants at levels 10,000 times legal limits.
By using fabric to fill conduits leading into the pit, and by filling the pit itself with concrete, TEPCO confirmed it had stopped the leak about 6 hours after it was discovered.