On 11 December 2013, the Nuclear Regulation Authority (NRA) of Japan provided the IAEA with an update on radioactivity in seawater at TEPCO's Fukushima Daiichi Nuclear Power Station (NPS).
This update states that the concentrations of Cs-134, Cs-137, total Beta and H-3 were relatively stable from 25 November to 1 December 2013 at the Nuclear Power Station, as well as cooperative activities with the IAEA on marine monitoring.
In addition, the NRA provided an update on the monitoring report for radioactivity obtained from sea water samples taken at a distance of two to 200 kilometers from TEPCO's Fukushima Daiichi NPS. During the period of 2 to 8 December 2013, the monitoring points, T-1 and T-2-1, located at the shoreline and directly adjacent to the NPS, indicated that the concentrations of all radionuclides (i.e. Cs-134, Cs-137, total Beta and H-3) were relatively stable.
The NRA also issued a news release on its activities to monitor removal of fuel from Unit 4.