Since the March 2011 disaster, Fukushima No. 1 nuclear plant has been constantly monitored. The Tokyo Electric Power Company (Tepco) noticed a rise in the level of radioactive tritium in seawater within the harbor at the crippled plant. The samples were collected on June 21, 2013 and they contained around 1,100 becquerels of tritium per liter.
This is the highest level of tritium detected in seawater since the nuclear crisis occurred at the plant. One of the officials from the Nuclear Regulation Authority said that the groundwater containing radioactive substances might be dripping into the harbor from the plant site. The official went on to say that there is a need for a careful investigation, as the data collected by now are very limited.
Tepco stated that the sample with the highest tritium concentration was collected near the water intake, which was on the east side of the reactor 1 turbine building. It was also noticed that the level in the sample was more than double than that of the sample that was taken on June 10, 2013 in the same area.
The latest announcement was made after the utility detected high levels of radioactive tritium and strontium in groundwater from an observation well at the plant. The government also set a safety limit of tritium at 60,000 becquerels per liter of seawater.