On 21 February 2014, Japan provided the IAEA with an update on radioactivity in seawater at TEPCO's Fukushima Daiichi Nuclear Power Station (NPS).
This update on the daily monitoring by TEPCO of seawater near Fukushima Daiichi NPS indicates that the concentrations of all radionuclides (i.e. Cs-134, Cs--137, total Beta and H-3) were relatively stable from 10 to 18 February 2014 at the sampling points T-1 and T-2-1. The sampling points T-1 and T-2-1 near the Fukushima Daiichi NPS are sentinels to assess effects on the environment by incidents including a leakage of contaminated water. The Nuclear Regulation Authority has been closely observing the results of TEPCO's monitoring of seawater at these sampling points.
The updated information also provides details on the incidents of water leakage at the Fukushima Daiichi NPS that was reported by TEPCO to the Nuclear Regulation Authority of Japan (NRA) on 15 and 16 February 2014.
The NRA also provided an update on the sea area monitoring results for radioactivity obtained from sea water samples taken at a distance of two to 200 kilometers from TEPCO's Fukushima Daiichi NPS.