Strontium readings spike 6,500-fold in one day
FUKUSHIMA – Radiation levels in groundwater under Tokyo Electric Power Co.’s Fukushima No. 1 nuclear plant are soaring, Tepco said Friday after taking samples from an observation well.
Tepco said 400,000 becquerels per liter of beta ray-emitting substances such as strontium were detected in water sampled Thursday from the well located some 15 meters from a storage tank that leaked about 300 tons of highly radioactive water in August.
The level of becquerels, a record high for water in that well, was up 6,500-fold from the 61 becquerels found Wednesday.
Tepco was planning to pump groundwater up from different wells about 100 meters from the leaky tank for release into the Pacific before the water flows into the damaged reactor buildings and becomes heavily contaminated with radioactive materials.
But that plan appears in jeopardy because the sharp increase in the levels of radioactive materials in the observation well suggest the radioactive groundwater is spreading.
By law, water containing beta particle-emitting substances exceeding certain levels cannot be released into the sea. The upper limit is set at 30 becquerels per liter for strontium-90 and 60 becquerels for cesium-134.
Tepco also said water collected Thursday from a drainage ditch near the leaky tank contained 34,000 becquerels of beta particle-emitting substances per liter, compared with 2,300 becquerels the day before.
Water contaminated with radioactive materials flowed into the ditch when Typhoon Wipha hit the area this week, but then much of the water evaporated, leading to the surge in the density of beta particle-emitting materials there, Tepco officials explained.
It is believed some 400 tons of radioactive groundwater is flowing into the Pacific daily.
Officials said Thursday they will solicit proposals from both domestic and overseas nuclear experts and firms on how best to scrap the ruined reactors at Fukushima No. 1.
The International Research Institute for Nuclear Decommissioning will publicly seek ideas as early as this month, an institute official said.
While the body is not putting the entire decommissioning process out to tender, the move will be welcomed by the international community, which has long called for Japan to make better use of available expertise around the globe.
The institute, formed by nuclear-related firms and government-backed bodies in August to dismantle the crippled reactors, will screen decommissioning proposals and take the results to the government, the official said.
“We will set up a website in both Japanese and English to notify interested parties at home and abroad of our calls for decommissioning ideas so that we can offer more useful and practical proposals to the government,” the official said.