The Tokyo Electric Power Co. said Friday somewhere between 20 trillion to 40 trillion becquerels of the substance have leaked since May 2011 into the Pacific Ocean. A becquerel is defined as a unit of radioactivity, the quantity of radioactive material in which one nucleus decays per second.
The tritium leaked into water from the emergency cooling system at the Fukushima No. 1 nuclear power plant since the plant's nuclear crisis March 2011, the power company reported to the Nuclear Regulation Authority.
The normally allowed range of tritium allowed into the sea is 22 trillion becquerels a year, so the amount that has leaked since May 2011 is roughly within range, Kyodo News reported Saturday. Still, the toxic water was leaked in an uncontrolled manner.